Kei Miyamoto MD PhD, Orthopaedic Surgeon, Spine Surgeon

Abstract: STUDY DESIGN: Retrospective analysis of factors related to kidney-type interbody spacer subsidence (SS) in transforaminal interbody fusion (TLIF). OBJECTIVE: To determine the risk factors for SS in TLIF using kidney-type spacers. SUMMARY OF BACKGROUND DATA: SS into the vertebral body, a major complication of TLIF, has not been studied extensively. METHODS: Between July 2004 and May 2006, 54 consecutive patients with lumbar dysplastic changes or degenerative disc diseases underwent TLIF using 82 kidney-type spacers with iliac bone grafts. All were followed-up for more than 2 years (mean, 2 y, 11 mo). SS was defined as disc height loss >2 mm. Risk factors analyzed for SS included spacer location in the intervertebral space (IVS, anterior, center, and posterior), sex, age, body mass index, and disease (spondylolisthesis, degenerative disc disease). Clinical outcomes were assessed using the Japanese Orthopedic Associated Score for back pain, as were adjacent segment disorder and nonunion. RESULTS: Of the 82 spacers, 66 were located in the center of the IVS and 16 anteriorly. There were 18 SS. Spacer position at the center of the IVS (P<0.001) and older age (P<0.001) were significantly associated with SS, with the first 2 factors having a synergistic effect. Adjacent level disorder (n=5) and nonunion (n=3) were observed only in patients with spacers positioned at the center of the IVS. CONCLUSIONS: Kidney-type spacers should be located in the anterior portion of the IVS to prevent subsidence of the intervertebral body, especially in patients with elderly age.

Abstract: STUDY DESIGN.: Comparison of magnetic resonance imaging (MRI) and computed tomography-myelography (CTM) for cervical intracanalar dimensions. OBJECTIVE.: To compare the capability and reproducibility of MRI and CTM in measuring the cross-sectional morphology of intracanalar lesions of the cervical spine. SUMMARY OF BACKGROUND DATA.: The relative advantages and disadvantages of MRI and CTM in measuring cervical intracanalar dimensions are poorly understood. METHODS.: MRI and CTM were used to measure cervical disc levels in 45 subjects with various cervical spinal diseases. Measurements included dural area, dural anteroposterior (A-P) diameter, dural right-left (RL) diameter, cord area, cord anteroposterior (A-P) diameter, cord right-left (RL) diameter and cerebrospinal fluid (CSF) space (anterior and posterior). Each section was graded by 2 orthopedic surgeons for degree of stenosis (Grades, 0-3), and the intra- and interobserver reproducibility of these measurements (intraclass correlation coefficients: ICC) was assessed. RESULTS.: In both CTM and MRI, intra- and interobserver reproducibility (ICC) ranged from 0.702 to 0.989, suggesting that both imaging methods are reproducible. Importantly, CTM measurements of dural area, dural A-P diameter, dural RL diameter, and CSF space (anterior and posterior) were slightly, but significantly (P < 0.001), larger than MRI measurements. In contrast, MRI measurements of cord area, cord A-P diameter, and cord RL diameter were slightly, but significantly (P < 0.001), larger than CTM measurements. Degree of stenosis was significantly more severe in MRI than in CTM. CONCLUSION.: Both CTM and MRI provided reproducible measurements of cervical intracanalar dimensions. Measurements of dura were slightly larger in CTM, whereas measurements of spinal cord were slightly larger in MRI, making stenosis more severe in MRI than in CTM. The clinical relevance of these slight differences requires further examination.

Abstract: STUDY DESIGN: A study was performed using an axial loading device in healthy young subjects. OBJECTIVE: To determine whether sagittal alignment during axial loading using a compression device can accurately simulate the standing posture. SUMMARY OF BACKGROUND DATA: Axial compression devices are widely used for simulation of standing position during magnetic resonance imaging (MRI) or computed tomography (CT) scans. However, images taken during axial loading have not been compared with those obtained in a standing posture. METHODS: The study population comprised 14 asymptomatic healthy volunteers (7 men and 7 women: age 21-32, mean 27 years). Lumbar lateral radiograph films obtained in the standing posture (standing condition), lumbar CT images with axial loading using a DynaWell compression device (axial loading condition), and CT images without loading (control) were compared. Changes in spinal length, lumbar disc height, segmental lordotic angle, and total lumbar lordotic angle were compared among the conditions. RESULTS: Spinal length was significantly decreased in both the axial loading and standing conditions compared with controls. The magnitude of the changes was greater in the standing condition than in the axial loading condition. Segmental lordotic angle at L2/3 and L3/4 was significantly increased in both axial loading and standing conditions. However, disc lordotic angle at L5/S was significantly decreased in the axial loading condition, while the standing condition showed no significant change. Consequently, the pelvic angle showed a significant decrease in the axial loading condition. CONCLUSION: The compression device simulates the lumbar segmental alignment change from supine to standing posture in L1/2, L2/3, L3/4, and L4/5. However, in L5/S, axial loading using the DynaWell altered lumbar segmental alignment with a kyphotic change, while no significant difference was observed in this level between standing and supine positions. Awareness of these phenomena are essential for accurate interpretation of imaging results.

Abstract: STUDY DESIGN: A prospective study on the clinical outcomes in patients with tuberculous spondylitis treated by a 2-stage operation (posterior and anterior) using posterior spinal instrumentation. OBJECTIVE: To evaluate the clinical outcomes of the 2-stage surgical treatment (first stage: placement of posterior instrumentation and second stage: anterior debridement and bone grafting) for tuberculous spondylitis. SUMMARY OF BACKGROUND DATA: There have been few reports describing the effects of 2-stage surgical treatment for tuberculous spondylitis. METHODS: Ten patients (5 men and 5 women) with tuberculous spondylitis were treated by 2-stage operations. Age at the initial operation was 64.6+/-14.8 years (average+/-SD) (range: 47 to 83 y). The clinical outcomes were evaluated before and after the surgery in terms of hematologic examination, pain level, and neurologic status. Bone fusion and changes in sagittal alignment were examined radiographically. RESULTS: All patients showed suppression of infection, bony fusion, relief of pain, and recovery of neurologic function. No significant changes were observed in kyphosis angle at the final follow-up. There were no incidences of severe complications or recurrence. CONCLUSIONS: Our results showed that posterior and anterior 2-stage surgical treatment for tuberculous spondylitis is a viable surgical option for cases in which conservative treatment has failed. However, the changes in sagittal alignment showed that this strategy provides limited kyphosis correction.

Abstract: The number of participants in thoracic or abdominal examinations using multi-detector-row CT (MDCT) has been increasing recently. If the degree of progress of osteoporosis can be estimated using these images, it may be useful as it will allow predictions of vertebral fractures without an additional radiation exposure. The aims of this study were to investigate segmental variations in bone mineral density (BMD) distributions of thoracic and lumbar vertebral bodies and to show specific differences according to age and gender. A large database including 1,031 Japanese subjects for whom MDCT was used to examine various organs and tissues was utilized in this study for trabecular BMD at thoracic and lumbar vertebrae. In relationship to vertebral level, L3 had the lowest trabecular BMD. BMD tended to gradually increase from L3 to T1 in all age categories. Also, there was a moderate correlation between vertebrae whose distance from each other was great whereas there was a high correlation between adjacent vertebrae. It may be appropriate to use an arbitrary vertebra as a first approximation for assessing vertebrae that are in the area of predilection for the fracture; however, to better understand their behavior, it may be necessary to measure BMD directly in this region. This study showed trabecular BMD distribution at healthy thoracic and lumbar vertebrae in Japanese subjects and specific differences in age and gender. Improved knowledge about vertebral BMD may help with the diagnosis of primary osteoporosis using MDCT.

Abstract: BACKGROUND: Little epidemiological research on characteristics of upper extremity injuries resulting from snowboarding has been conducted, particularly in relation to snowboarding stance, falling direction, and the side of the body where the injury occurs. HYPOTHESIS: Snowboarding stance and the direction of the fall may influence the frequency of the side or the location of the upper extremity injury. STUDY DESIGN: Descriptive epidemiology study. METHODS: This study analyzed the information obtained from 1918 patients with fractures or dislocations of the upper extremity (excluding the fingers and scapula) sustained during snowboarding/sliding between 2000 and 2008. Diagnosis, injured part and side, stance (regular or goofy), and falling directions were prospectively analyzed. Associations among these parameters were also analyzed. RESULTS: As characterized by skill level, patients were beginners (57.9%), intermediates (38.0%), and experts (4.0%). Eighty-eight percent had not received instruction from licensed instructors. Diagnoses included wrist fractures (53.7%), upper arm fractures (16.8%), shoulder dislocations (11.5%), and elbow dislocations (9.8%). In sum, 1742 (90.8%) patients were in regular stance when they fell, whereas 176 (9.2%) were in goofy stance. There was a significant difference in the prevalence of the injured side between the 2 stances. When the injured sides were classified according to the sliding direction, wrist fractures (61.7%) occurred on the side opposite the sliding direction, whereas shoulder dislocations (65.6%), upper arm fractures (82.9%), and elbow dislocations (79.8%) occurred on the same side as the sliding direction. When the injured sides were classified according to the falling direction, wrist fractures (68.1%) and elbow dislocations (63.5%) occurred because of backward falls, and shoulder dislocations (68.9%) and upper arm fractures (60.7%) occurred because of forward falls. CONCLUSION: Two snowboarding stances as well as 2 falling directions had a significant influence on the frequency of the injured side in the upper extremity.

Abstract: BACKGROUND: The number of patients suffering from degenerative diseases in the lumbar spine is increasing in Japan. Although various scales to measure disability or quality of life in patients with low back pain and/or lumbar diseases are currently available, it has been shown that one questionnaire is not always compatible with another. Our purpose is to evaluate the association and differences between the Japanese version of the Roland-Morris Disability Questionnaire and the Japanese Orthopaedic Association score for low back pain. METHODS: These two scales were examined and compared using data from 602 patients with low back pain and/or lumbar disease. The associations between the Japanese version of the Roland-Morris Disability Questionnaire and each subscale in the Japanese Orthopaedic Association score in back pain dominant group and leg pain dominant group, and with respect to six pathological conditions (i.e., sciatica, spondylosis, spondylolisthesis, lumbar spinal canal stenosis, muscular pain, traumatic pain) were analyzed. RESULTS: While the Japanese version of the Roland-Morris Disability Questionnaire and the Subjective and Activities of daily living (ADL) subscale of the Japanese Orthopaedic Association score showed a good correlation (r > 0.60), the Japanese version of the Roland-Morris Disability Questionnaire and the Clinical subscale showed a weak correlation (r = 0.35). Among the six pathological conditions, the correlation between the Japanese version of the Roland-Morris Disability Questionnaire and the Japanese Orthopaedic Association score was the lowest (r = 0.66) in the lumbar spinal canal stenosis category. CONCLUSIONS: The clinical signs in patients with low back pain and/or lumbar diseases are not associated closely with the Japanese version of the Roland-Morris Disability Questionnaire. Therefore, a combination of the Japanese version of the Roland-Morris Disability Questionnaire and the Japanese Orthopaedic Association score can provide wide-ranging assessment of the level of impairment in patients with low back pain and/or lumbar diseases.

Abstract: Although cervical anterior osteophytes accompanying diffuse idiopathic skeletal hyperostosis (DISH) are generally asymptomatic, large osteophytes sometimes cause swallowing disorders. Surgical resection of the osteophyte has been reported to be an effective treatment; however, little study has been given to the recurrences of osteophytes. A prospective study was performed for seven patients who underwent surgical resection of cervical anterior osteophytes for the treatment of recalcitrant dysphagia caused by osteophytes that accompanied DISH. The seven patients were six men and one woman ranging in age from 55 to 78 years (mean age = 65 years). After a mean postoperative follow-up period of 9 years (range: 6-13 years), surgical outcomes were evaluated by symptom severity and plain radiographs of the cervical spine. On all operated intervertebral segments, the effect of postoperative intervertebral mobility (range of movement > 1 degree) on the incidence of recurrent osteophytic formation (width > 2 mm) was analyzed by Fisher's exact test. Complete relief of the dysphagia was obtained within one month postoperatively in five patients, while it was delayed for 3 months in two patients. All of the patients developed recurrent cervical osteophytic formation, with an average increase rate of approximately 1 mm/year following surgical resection. Of the 20 operated intervertebral segments, the incidence of recurrent osteophytes was significantly higher (P = 0.0013) in the 16 segments with mobility than in the four segments without mobility. Five of the seven patients remained asymptomatic, although radiological recurrence of osteophytes was seen at the final follow-up. The two remaining patients complained of moderate dysphagia 10 and 11 years after surgery, respectively; one of these two required re-operation due to progressive dysphagia 11 years postoperatively. In patients with cervical DISH and dysphagia, surgical resection of osteophytes resulted in a high likelihood of the recurrence of osteophytes. Therefore, attending surgeons should continue to follow these patients postoperatively for more than 10 years in order to assess the regrowth of osteophytes that may contribute to recurrent symptoms.

Abstract: We report 2 cases of transforaminal lumbar interbody fusion for failed Graf ligamentoplasty. Both patients had residual or recurrent low back pain and leg pain after Graf ligamentoplasty, caused by lumbar segmental instability or narrowing of their intervertebral foramens. The pain improved markedly after the revision surgery. We recommend transforaminal lumbar interbody fusion for failed Graf ligamentoplasty, as it provides rigid interbody bony fusion and obviates complete exposure of the dural sac or dural tube.

Abstract: STUDY DESIGN: Retrospective study of clinical outcomes of 1-staged combined cervical and lumbar decompression for patients with tandem spinal stenosis (TSS). OBJECTIVE: To describe middle-term clinical outcomes of this procedure. SUMMARY AND BACKGROUND DATA: Little is known with regard to the clinical outcomes of 1-staged combined cervical and lumbar decompression for TSS. METHOD: Surgical intervention, perioperative complications, and clinical outcomes were reviewed in 17 TSS patients who underwent 1-staged combined cervical and lumbar decompression and were followed-up for more than 3 years. Clinical symptoms were evaluated using the Japan Orthopaedic Association Score for back pain (JOA-B) and cervical myelopathy (JOA-C) and activity of daily life, before surgery, at 6 months postoperatively, and at final follow-up. Patient satisfaction was determined at final follow-up. RESULTS: The JOA-B, JOA-C scores, and activities of daily life improved significantly 6 months after surgery, but ultimately deteriorated. At 6 months, the improvement ratios in JOA-B and JOA-C scores were positively correlated. Complications involving other parts of the body significantly influenced clinical deterioration. Twelve patients (71%) were satisfied. CONCLUSIONS: One-staged combined cervical and lumbar decompression for TSS provided fair results, even for elderly patients. Although reasons other than spinal pathology affected symptom deterioration at final follow-up, most patients expressed satisfaction at middle-term follow-up periods.

Abstract: We describe a 44-year-old woman who was diagnosed in childhood with vitamin D-resistant rickets, and who had paraparesis due to multiple spinal canal stenoses between C5 and L1 with ossification of the posterior longitudinal ligament and the yellow ligament. She was treated surgically with laminoplasty of the C2 through C7 levels and laminectomy from T8 through T11. Four months later, she underwent anterior fusion using an ilium graft by thoracotomy from the T12 to L1 levels. Six months after surgery, her symptoms improved. After 5 years, and with oral vitamin D, no progression of symptoms has been observed.

Abstract: STUDY DESIGN: A case report describing thoracic intervertebral disc degeneration and spondylolisthesis associated with a Schmorl node in a young athlete, which was successfully treated by anterior interbody fusion (AIF). OBJECTIVE: To describe a rare pathologic condition with a clinical outcome of a surgical intervention. SUMMARY OF BACKGROUND DATA: Intervertebral degeneration and spondylolisthesis of the lower thoracic spine associated with a Schmorl node in a young athlete has not been reported. METHODS: A 19-year-old male amateur soccer player presented with severe back pain during motion. This pain was associated with intervertebral disc degeneration, spondylolisthesis, and a Schmorl node at the Th11/12 level. He was surgically treated by AIF. RESULTS: The AIF resulted in a solid fusion, an improvement in sagittal alignment, and amelioration of symptoms. CONCLUSION: The AIF procedure was effective for lower thoracic symptomatic intervertebral disc degeneration and spondylolisthesis associated with a Schmorl node.

Abstract: INTRODUCTION: Spinal injuries resulting from entering into water usually occur in the cervical region, with few reported in the thoracolumbar region. Although the mechanism of cervical spine injury caused by diving is known, less is known regarding the mechanism of upper lumbar spine injury. MATERIALS AND METHODS: The study subjects were five patients (mean age, 32.8 years), inexperienced in diving from heights, who were referred for burst fractures (Denis type B) at L1 caused while jumping into a river from a 12-m-high bridge between 2004 and 2005. Three patients were treated surgically and two were treated conservatively. Their clinical outcomes were reviewed and the mechanism of upper lumbar spine injury was discussed. RESULTS: No patient experienced neurological deficit or low back pain after treatment, and all returned to their previous activities within 1 year. Impact with the surface of the river with back and hip flexed may be a major cause of upper lumbar spine injury. CONCLUSIONS: To minimize the incidence of upper lumbar burst fracture during recreational high jumping into water, it is important that jumpers, especially inexperienced jumpers, should be instructed to jump with their backs and hips straight.

Abstract: INTRODUCTION: Spinal shortening is indicated for osteoporotic vertebral collapse. However, this surgical procedure has not been indicated for more than two vertebral levels that are not adjacent. We experienced a rare case of paraparesis due to osteoporotic vertebral collapse of two vertebral bodies with a normal vertebra in between and treated successfully by the double-level posterior shortening procedure. MATERIALS AND METHODS: A 79-year-old woman suffered from delayed paraparesis 2 years after L1 and Th11 vertebral body compression fracture. Plain X-ray photographs showed Th11 and L1 vertebral body collapse, Th7 compression fracture and a kyphosis angle of 30 degrees from Th10 to L2. Plain magnetic resonance imaging showed spinal canal stenosis at Th11 and L1 vertebral body levels. She was treated by double-level posterior spinal shortening using pedicle screw and hook systems. RESULTS: After the procedure, the patient's kyphosis angle decreased to 10 degrees and her back pain, leg pain, and sensory deficits improved. She was able to walk by herself. Although new vertebral compression fractures occurred at L4 and L5 in the follow-up period, there has been no deterioration of the neurological symptoms 5 years after the operation. CONCLUSION: Delayed paraparesis after double-level thoracolumbar vertebral collapse due to osteoporosis was treated successfully by double-level posterior spinal shortening using a pedicle screw and hook system.

Abstract: STUDY DESIGN: A case report of atypical mycobacterial spinal osteomyelitis. OBJECTIVE: To describe a rare case of spinal osteomyelitis and associated thoracolumbar kyphoscoliosis caused by atypical mycobacteria, and successful treatment by a 2-stage surgical intervention. SUMMARY OF BACKGROUND DATA: Vertebral osteomyelitis caused by atypical mycobacteria is very rare. METHODS: The patient was an 18-year-old woman with vertebral osteomyelitis of Th12-L1 caused by Mycobacterium avium complex. Plain radiographs revealed vertebral collapse of Th12, scoliosis, and kyphosis. RESULTS: Two-stage surgical treatment (first: posterior instrumentation; second: anterior debridement and bone graft) was performed. At 5 years after surgery, the patient is almost free of the preoperative symptoms with no evidence of disease recrudescence. Plain radiograph film demonstrated amelioration of scoliosis and kyphosis, and consolidation of the anterior bone graft. CONCLUSION: A rare case of intractable spinal osteomyelitis due to atypical mycobacteria in a nonimmunocompromised patient was treated successfully with 2-stage surgical treatment.

Abstract: BACKGROUND: Several mechanisms of how abdominal belts affect the trunk have been postulated, but very little is known about how the belts affect the cross-sectional shape of the trunk during trunk muscle exertions. METHODS: To evaluate the effects of abdominal belts on the cross-sectional shape of the trunk during contraction of the trunk muscles, CT images at the third lumbar vertebra level of 20 healthy males (age: 23-45 years) under 8 different conditions (combinations of performing or not performing the Valsalva maneuver after full inhalation or at neutral respiratory state, while wearing or not wearing a 100-mm-wide abdominal belt) were evaluated. The cross-sectional shapes of the trunk seen on CT images taken at the level of the 3rd lumbar vertebra were compared using three-way ANOVA. FINDINGS: Wearing the belt decreased the cross-sectional area of the trunk, and wearing it while performing the Valsalva maneuver and during inhalation compressed the postero-lateral part of the trunk and made the trunk nearly round by increasing the ratio of the anterior-posterior width to the right-left width. INTERPRETATION: A wide belt cinched around the abdomen exerts external hoop tension on the trunk and stiffens the trunk. When the belt is worn during the Valsalva maneuver after deep inhalation, the posterolateral portion of the trunk is compressed and the trunk becomes circular.

Abstract: INTRODUCTION: A case of combined epiconus and cauda equina syndrome due to multilevel spinal canal stenosis of the thoracolumbar spine is reported. METHODS: A 76-year-old man with multilevel spinal canal stenosis of the thoracolumbar spine (Th11-12, L2-S) who showed symptoms of epiconus syndrome was reported. First, we performed anterior decompression and fusion at the thoracolumbar junction (decompression: Th11-12, fusion: Th10-L2), which ameliorated his symptom partially. However, he presented cauda equina symptoms. Then, he underwent posterior spinal decompression (L3-5) and fusion (Th12-L5). RESULTS: After anterior decompression, several symptoms disappeared. However, motor and sensory disturbance below L4 and bladder-bowel disturbance remained. We then performed a secondary operation. At three years' follow-up, he was able to walk with the aid of a cane. CONCLUSIONS: Combined epiconus and cauda equina syndrome due to multilevel spinal canal stenosis was treated by combined two-stage anterior and posterior decompression. In this case, multilevel decompression via anterior and posterior approaches was necessary to relieve the symptoms.

Abstract: Spondylolysis affects mostly the lower lumbar spine and rarely the upper lumbar spine. In a literature research, we found that the descriptions of spondylolysis of the upper lumbar spine had been reported mainly with the outcomes of conservative treatment using lumbosacral supports. However, an indication of surgical treatment has rarely been reported. Ravichandran et al reported 2 cases of spinal fusion, decompression or a combination of these procedures, but the procedures have not proved satisfactory in cases of upper lumbar spondylolysis. We found no reports of segmental wire fixation and bone grafting for upper lumbar spondylolysis. Herein, we report spondylolysis of the second lumbar vertebra in a 27-year-old man. He presented with pain and tenderness at the L2 spinous process, and swollen paravertebral muscles. The patient first became aware of lumbago at age 24 years. Much of his work involved heavy labor. He was diagnosed with spondylolysis of L2 and treated conservatively by a general orthopedist from age 25 to 27 years, but without improvement. We performed segmental wire fixation of the transverse and spinous processes of L2, followed by a bone graft. Six months after surgery, the lumbago had resolved and the patient was able to return to work. Three years after surgery, his pain is completely resolved. This is the first report in the English literature in which a successful indication for symptomatic spondylolysis in the upper lumbar spine is described.

Abstract:

Abstract: STUDY DESIGN: A case report of ossification of the posterior longitudinal ligament (OPLL) combined with ossification of the ligamentum flavum, or yellow ligament (OYL), in the upper thoracic spine. OBJECTIVE: To describe a rare clinical entity and its management pitfalls in a patient with upper thoracic myelopathy due to combined OPLL and OYL. METHODS: A 52-year-old woman developed paresthesia and paraparesis of both legs. One month prior to admission she fell and became unable to walk. She was diagnosed as having upper thoracic myelopathy due to combined OPLL and OYL and was treated by two-stage anterior and posterior spinal decompression. Posterior decompression was achieved first by laminoplasty at C3-Th1 and laminectomy of Th2 and Th3. RESULTS: After posterior decompression, her symptoms immediately and dramatically improved. However, symptoms recurred after she was able to achieve a sitting or standing position. We then performed anterior decompression at Th2, which again improved her symptoms. At two years post-surgery, she is ambulatory with the use of a cane. CONCLUSION: Upper thoracic myelopathy due to OPLL and OYL was treated by combined 2-staged anterior and posterior decompression. In this case, posterior decompression alone was inadequate to relieve the symptoms of this pathological condition.

Abstract: INTRODUCTION: The effectiveness of segmental wire fixation technique in repairing lumbar spondylolysis has already been reported. However, whether the technique can be indicated for spondylolysis associated with spina bifida, which is occasionally found with spondylolysis, is not well known. In this study, the authors report the mid-term clinical outcome of the procedure performed in patients with symptomatic lumbar spondylolysis associated with spina bifida occulta. MATERIALS AND METHODS: Among 20 patients with symptomatic lumbar spondylolysis who underwent segmental wire fixation between 1996 and 2001, four patients associated with spina bifida occulta were evaluated with an average of 32 months follow-up. Bony union at spondylolysis sites and spina bifida was evaluated using plain X-rays and computed tomography (CT) scans. Clinical symptoms were assessed using Japanese Orthopedic Association scores for back pain (JOA scores) and Henderson's evaluation of functional capacity. RESULTS: The radiographic examinations of the latest follow-ups revealed the following results. Pars defect; in three cases with bilateral defect, one case healed bilaterally and two healed only unilaterally. One case with unilateral defect healed. Spina bifida; two cases showed bony union and two showed no union. Of the four patients operated, two were rated excellent with the remaining two good according to Henderson's evaluation. The recovery rate of JOA score was averaged at 69.7 +/- 23.5%. No serious complications were noted. CONCLUSIONS: In four cases associated with lumbar spondylolysis and spina bifida, segmental wire fixation provided satisfactory clinical outcomes.

Abstract: BACKGROUND CONTEXT: Chronic, continuous stress at the junction of a stable/unstable site of the spine in diffuse idiopathic skeletal hyperostosis (DISH) has been reported to cause a nonunion. Back pain resulting from the nonunion has been rarely reported and few operative treatments have been suggested. PURPOSE: To report and discuss the pathogenesis, treatment, and surgical outcome of a rare cause of back pain. STUDY DESIGN: Case report of back pain caused by a single lumbar segment is lacking bony union at the caudal end of a fused spine associated with diffuse idiopathic skeletal hyperostosis. METHODS: Back pain in a 66-year-old man who had suffered for 10 years worsened. The back pain and thigh pain became intolerable, and the left buttock and thigh became numb. Radiographs and computed tomography images showed continuous hyperostosis in the anterior aspect of the vertebral bodies from C2 to L2. At the caudal adjacent level of these fused segments, L2/3 level was mobile and had canal stenosis. Decompression and posterior lumbar interbody fusion (PLIF) were performed. RESULTS: The pain disappeared soon after the operation. The nonunited segment showed bony union at the 5-year follow-up. CONCLUSIONS: PLIF may be an option for surgically treating symptomatic nonunited lumbar segments at the caudal end of a fused spine with DISH in cases unresponsive to conservative treatment.

Abstract: INTRODUCTION: Recently, solitary fibrous tumors occurring in spine-related lesions have been reported. However, the destruction of vertebral bodies by this type of tumor has not been reported. MATERIALS AND METHODS: A 71-year-old female presented with pain from a mass on the right side of her neck. Plain radiographs of the cervical spine showed collapse of the C5 vertebral body and dislocation of the C4 vertebral body. The MRI image showed a large mass surrounding C4 and C5, which had low signal intensity in the T1W image and high signal intensity in the T2W image. At first, resection of the tumor and spinal fusion was performed by anterior approach. RESULTS: Histology revealed a solitary fibrous tumor with proliferating spindle cells. Immunohistochemistry showed positive stains for vimentin and CD34. One year postoperatively, a local recurrence manifested extensive destruction of the C4 and C5 vertebral bodies. Then, palliative surgery with posterior cervical instrumentation and radiation therapy were performed. Because the destruction proceeded and the rods were broken 2 years after, she underwent additional occipito-cervical instrumentation. CONCLUSIONS: This is the first report of a solitary fibrous tumor that involves the destruction of the spinal structure. An extensive destruction of the vertebral body by the solitary fibrous tumor needs to be aware in treating this tumor with spinal involvement.

Abstract: BACKGROUND CONTEXT: Prader-Willi syndrome is a rare disease associated with a variety of musculoskeletal abnormalities, including scoliosis, joint hyperlaxity, and delayed bone age. To the authors' knowledge, only a few cases of surgical treatment for scoliosis associated with Prader-Willi syndrome have been reported. PURPOSE: To report a rare case of scoliosis associated with Prader-Willi syndrome and the effect of surgical treatment and to review the literature on this condition. STUDY DESIGN/SETTING: Case report of a patient treated in Gifu, Japan. METHODS: The patient, a 16-year-old girl with Prader-Willi syndrome, had severe scoliosis with triple curves (T1 to T5, 43 degrees T5 to T11, 60 degrees; T11 to L3, 52 degrees), making it difficult for her to maintain balance while standing or walking. She underwent surgical correction and fusion for the scoliosis via the posterior approach. She was followed up for 2 years, and her clinical symptoms and plain X-ray films were evaluated. RESULTS: The thoracic curve was corrected to 21 degrees (correction rate, 65%) and the lumbar curve to 28 degrees (correction rate, 46%). Her symptoms were relieved. CONCLUSION: A case of scoliosis with Prader-Willi syndrome was successfully treated surgically using a posterior approach and minimizing possible risks associated with surgery in patients with this syndrome.

Abstract: We report the case of a 7-year-old boy with thoracolumbar scoliosis and central core disease who had a history of malignant hyperthermia. He had scoliosis with Cobb's angle deteriorating to 67 degrees (thoracic) and 59 degrees (lumbar). A provocation test of general anesthesia was performed to confirm no hyperthermic reaction. Then, he underwent surgical correction by a posterior approach. The thoracic curve was reduced to 38 degrees and the lumbar curve to 42 degrees . He has been followed up for 2 years without any complications. This is the first report with a detailed description of perioperative management on surgical treatment of scoliosis associated with central core disease.

Abstract: STUDY DESIGN: A comparative study of aggrecanases and aggrecan fragmentation profile in the human intervertebral disc at early and advanced stages of disc degeneration. OBJECTIVE: To determine differences in the content of the aggrecanases and the profile of aggrecan fragmentation in early and advanced stages of disc degeneration using cadaveric human intervertebral discs. SUMMARY OF BACKGROUND DATA: Aggrecanases and aggrecanase-generated aggrecan fragments have been found in human degenerated discs. However, the association between the grade of disc degeneration and the content of the aggrecanases and the profile of aggrecan fragments has not been well studied. METHODS: A total of 108 cadaveric donor spines were assessed by MRI T2 imaging and graded based on the Thompson scale. Twelve donor spines (average age, 63 years), each specifically exhibiting 2 different stages (Grade 2 and Grade 4) of disc degeneration at different disc levels, were included in this study. After harvesting the preselected discs, tissue samples were obtained from the center of the nucleus pulposus (NP) and the middle zone of the anulus fibrosus (AF). The amount of the aggrecanases, specifically ADAMTS-4 and ADAMTS-5, and the pattern of aggrecan fragmentation in the isolated tissues were assessed by western blot using specific antibodies. RESULTS: In both NP and the AF tissues, the amount of ADAMTS-4 detected was higher in disc tissues with a higher level of degeneration (Grade 4) than in Grade 2 disc tissues with a lower level of degeneration. However, the amount of ADAMTS-5 detected did not differ between the 2 disc tissue grades. The aggrecan fragmentation analysis of these samples demonstrated the presence of aggrecanase-mediated fragmentation in both groups; however, there was no apparent difference in the aggrecan fragmentation profile between discs at early and advanced stages of disc degeneration. CONCLUSION: Aggrecanases are involved in aggrecanolysis at both the early and advanced stages of disc degeneration. The aggrecan fragmentation profile analysis demonstrates the involvement of aggrecanases, as well as that of matrix metalloproteinases and/or cathepsins, during disc degeneration.

Abstract: A patient with postlaminectomy kyphosis with a neurological deficit which developed following the initial surgical treatment is reported. A 49-year-old man, complaining of neck pain, sought treatment in 1995. An extramedullary cervical spinal tumor was diagnosed and C2-C4 laminectomy and resection of the tumor were performed. Recurrence of the tumor was seen 1 year later and a second tumor resection and radiation therapy were performed. One year after the second resection of the tumor, X-rays of the cervical spine revealed kyphosis. Anterior spinal fusion without instrumentation was performed followed by immobilization using a halo vest for 4 months. However, pseudoarthrosis and progression of the kyphosis occurred postoperatively. Iliac bone grafting at the pseudoarthrosis site and posterior internal fixation with lateral mass plates was performed. Bony fusion between the graft and C6 vertebra was obtained after these procedures, but the neurological deficits were not completely resolved. Clinicians who treat spinal cord tumors may learn from this treatment failure.

Abstract: A vertebral hemangioma with dural compression and neurological deficit is rare. We report a symptomatic lumbar vertebral hemangioma which was successfully managed with total spondylectomy. The patient was a 31-year-old man whose chief complaint was low back pain. He had a slight sensory disturbance in the right thigh. Plain radiography and magnetic resonance imaging (MRI) revealed a tumor in the second lumbar vertebra, which extended into the spinal canal, compressing the dura. A percutaneous needle biopsy did not provide a pathological diagnosis. Before surgery, the arteries feeding the tumor were embolized using coils. We performed a total spondylectomy of the second lumbar vertebra with anterior reconstruction with a glass ceramic spacer and posterior instrumentation. The intraoperative pathological examination revealed a hemangioma of the lumbar spine. At the 4-year follow-up examination, the patient is completely asymptomatic without evidence of tumor recurrence.

Abstract: STUDY DESIGN: In vitro assessment of the effects of recombinant human osteogenic protein-1 (rhOP-1) on the proteoglycan metabolism of human intervertebral disc cells. OBJECTIVES: To determine whether rhOP-1 is effective in stimulating the cell proliferation and proteoglycan metabolism of human intervertebral disc cells cultured in alginate beads. SUMMARY OF THE BACKGROUND DATA: OP-1 has been shown to stimulate the proteoglycan and collagen synthesis of rabbit intervertebral disc cells in vitro. In vivo, a single injection of rhOP-1 restored the disc height of a degenerated disc in the rabbit anular-puncture model. The effect of rhOP-1 on human intervertebral disc cells remains unknown. METHODS: Human nucleus pulposus and anulus fibrosus cells were isolated from the discs of 4 cadaveric spines and one surgical specimen. After preculture for 7 days, alginate beads containing nucleus pulposus and anulus fibrosus cells were cultured for 21 days in media containing 10% fetal bovine serum with 0, 100, or 200 ng/mL rhOP-1 and supplements. The synthesis and accumulation of proteoglycans and the DNA content were biochemically assessed. RESULTS: The addition of rhOP-1 to the media resulted in the prevention of a decreased cell number during culture. Treatment with rhOP-1, compared with the control condition (10% fetal bovine serum), significantly upregulated proteoglycan synthesis and accumulation in alginate beads in all cases tested. A longer exposure over 14 days to rhOP-1 resulted in a pronounced response. The retention of newly-synthesized proteoglycan was higher in the rhOP-1-treated cells than in the control. CONCLUSIONS: rhOP-1 was effective in stimulating the cell proliferation and proteoglycan metabolism of human intervertebral disc cells in vitro. The results supported the hypothesis that an in vivo injection of rhOP-1 may increase the metabolic activity of disc cells or prevent apoptosis of disc cells in a degenerated disc. However, the requirement for a long exposure to rhOP-1 for human cells may suggest the need for a prolonged supply of rhOP-1 by a drug delivery system or by repeated injections.

Abstract: STUDY DESIGN: The axonal growth potential of dorsal root ganglion (DRG) neurons in an organ culture system was investigated. OBJECTIVE: To examine the effects of neuronal injury and tumor necrosis factor-alpha (TNF-alpha) on the axonal growth potential of 2 types of nociceptive DRG neurons: nerve growth factor (NGF)-sensitive and glial cell line-derived neurotrophic factor (GDNF)-sensitive neurons. SUMMARY OF BACKGROUND DATA: Nerve ingrowth into the disc is recognized to be one of the causes of discogenic pain. Almost all of these disc-innervating neurons are NGF-sensitive. The axonal growth potential of NGF-sensitive neurons has not been investigated. METHODS: Adult Sprague-Dawley rats were used for immunohistochemistry (n = 7) and cell viability studies (n = 6). Bilateral L3-L5 DRGs, which were successfully removed without damage, were noncultured or cultured in serum-free medium containing TNF-alpha at 0, 0.01, 0.1, and 1 ng/mL for 48 hours (n = 5, each treatment). The DRGs were then immunostained for activating transcription factor 3 (ATF3, a marker for injured neurons) or double-stained for growth-associated protein 43 (GAP-43, a marker for axonal growth) with calcitonin gene-related peptide (CGRP, a marker for NGF-sensitive neurons) or isolectin B4 (IB4, a marker for GDNF-sensitive neurons). Cell viability was assessed by a lactate dehydrogenase (LDH) assay and an MTS assay (n = 6, each treatment). RESULTS: Immunoreactive evidence of injured neurons (ATF3 positive) was frequently observed in cultured DRGs, but never in noncultured DRGs. The percentage of neurons exhibiting axonal growth potential (GAP-43 immunoreactive) was significantly higher for NGF-sensitive neurons than for GDNF-sensitive neurons at any concentration of TNF-alpha. More than 95% of the cultured neurons were viable. CONCLUSIONS: The results suggest that the cultured DRG neurons exhibit pathologic changes similar to those found in injured neurons. NGF-sensitive neurons, which include disc-innervating neurons, may have a greater potential to extend their axons in response to neuronal injury under pathologic conditions in the presence of TNF-alpha than GDNF-sensitive neurons.

Abstract: INTRODUCTION: Factors influencing clinical outcomes of osteosynthesis for elderly patients with Garden stage I and II femoral neck fractures are not well understood. MATERIALS AND METHODS: To determine the factors influencing the clinical outcomes of in situ osteosynthesis in non-displaced femoral neck fractures in the elderly, radiographs and clinical data of patients were retrospectively analyzed. The subjects were 49 patients with femoral neck fractures (Garden stages I and II), who underwent osteosynthesis, with correctly inserted screws and with more than 2 years of follow up. The relationships between preoperative anteroposterior X-ray parameters including Garden stage, the presence or absence of spikes, the Singh grade, the Garden alignment index, the degree of impaction at the fracture site (the capital impaction index) and postoperative outcomes were analyzed. RESULTS: Among the 49 cases, there were eight unsuccessfully treated patients, two with non-union and six with late segmental collapse. The "without spikes" fracture type (P < 0.05) and the degree of capital impaction when the capital impaction index (P < 0.0001) was greater than the mean plus the standard deviation, were significantly associated with unsuccessful outcomes. CONCLUSION: Excessive shortening at the fracture site on the anteroposterior radiograph in the femoral neck fracture of Garden stages I and II can be used to predict poor outcomes from in situ osteosynthesis.

Abstract: STUDY DESIGN: The reliabilities of and correlations among 5 standard methods of assessing cervical sagittal alignment were evaluated. OBJECTIVE: To investigate the reliabilities of and correlations among 5 standard methods of assessing cervical sagittal alignment. SUMMARY OF BACKGROUND DATA: Although various cervical sagittal alignment assessment methods are widely used, their relative reliability and intercorrelation have not been reported. METHODS: From 442 lateral cervical radiographs, 40 with lordotic, 40 with straight or sigmoid, and 40 with kyphotic alignment were selected. Two orthopedic surgeons independently evaluated the sagittal alignment in each group twice using CCL, C1-C7 Cobb, C2-C7 Cobb, sagittal tangent, and the Ishihara methods. Intraobserver and interobserver reliabilities were confirmed and the correlations among the 5 methods were measured. RESULTS: Intraobserver and interobserver reliabilities for all 5 methods were good. In the lordotic group, the correlations among all 5 methods were consistently strong (r = 0.731 to 0.922). In the straight or sigmoid group, the correlations were weak to moderate among the CCL, C2-C7 Cobb, sagittal tangent, and Ishihara methods but tended to be weak between these 4 methods and the C1-C7 Cobb method (r = -0.245 to 0.777). In the kyphotic group, the correlations were also weak to moderate among the same 4 methods, and were statistically insignificant between them and the C1-C7 Cobb. CONCLUSIONS: The correlations among the CCL, C1-C7 Cobb, C2-C7 Cobb, sagittal tangent, and Ishihara methods are strong when lordosis is retained; otherwise, they are moderate to poor. In the kyphotic group, C1-C7 Cobb has no significant correlation with the other 4 methods.

Abstract: OBJECTIVE: Platelet-rich plasma (PRP) is a fraction of plasma that contains high levels of multiple growth factors. The purpose of this study was to examine the effects of PRP on cell proliferation and matrix synthesis by porcine chondrocytes cultured in alginate beads, conditions that promote the retention of the chondrocytic phenotype, in order to determine the plausibility of using this plasma-derived material for engineering cartilage. DESIGN: PRP and platelet-poor plasma (PPP) were prepared from adult porcine blood. Adult porcine chondrocytes were cultured in the presence of 10% PRP, 10% PPP or 10% fetal bovine serum (FBS) for 3 days. Cell proliferation, proteoglycan (PG) and collagen synthesis were quantified, and the structure of newly synthesized PG and collagen was characterized. RESULTS: Treatment with 10% PRP resulted in a small but significant increase in DNA content (+11%, vs FBS; P<0.01; vs PPP; P<0.001). PG and collagen syntheses by the PRP-treated chondrocytes were markedly higher than those by chondrocytes treated by FBS or PPP (PG; PRP: +115% vs FBS; +151% vs PPP, both P<0.0001, collagen; PRP: +163% vs FBS; +163% vs PPP, both P<0.0001). Biochemical analyses revealed that treatment with PRP growth factors did not markedly affect the types of PGs and collagens produced by porcine chondrocytes, suggesting that the cells remained phenotypically stable in the presence of PRP. CONCLUSION: PRP isolated from autologous blood may be useful as a source of anabolic growth factors for stimulating chondrocytes to engineer cartilage tissue.

Abstract: BACKGROUND: Although attention has been paid to the relationship between the changes in blood circulation in erector spinae muscles and back pain, little is known about their hemodynamics in several various comparable postures with and without loading. Studies on hemodynamics of erector spinae muscles using near-infrared spectroscopy have been performed on subjects and patients mainly in forward flexion positions. METHODS: Two near-infrared spectroscopes were used to measure oxygenated hemoglobin, deoxygenated hemoglobin, and total hemoglobin in bilateral erector spinae muscles at L2-3 in subjects in 9 postures, and holding no load, 10 kg or 20 kg in maximum flexed and lateral bending. Those three values in each posture and loading condition were expressed as a percentage of their corresponding values obtained in the standing upright position, and designated and statistically analyzed as %Oxy-Hb, %Deoxy-Hb and %Total-Hb, respectively. FINDINGS: %Total-Hb and %Oxy-Hb in maximum flexion were the most decreased. In maximum lateral bending, %Oxy-Hb only in the contralateral erector spinae muscles was decreased. When the load was 20 kg, the decreases in %Oxy-Hb were the largest in maximum flexion and lateral bendings. INTERPRETATION: Using two near-infrared spectroscopes allowed us to measure simultaneously the hemodynamics of bilateral muscles. They demonstrated different responses in each side. Asymmetrical posture and loading were accompanied by asymmetrical changes of the bilateral erector spinae muscles. Stretched muscle had less blood volume and oxygenation, both of which decreased with increasing load. These results showed that these postures and conditions might lead to fatigue of the ES muscles.

Abstract: STUDY DESIGN: Report of seven cases. OBJECTIVE: There is no general consensus on the best surgical procedures for late-onset complications of cervical operations. We reported seven patients who had been treated effectively by multilevel anterior corpectomy and fusion (ACF) as revision surgery of the cervical spine. SETTING: Gifu University Hospital, Gifu, Japan. METHOD: Multilevel ACF using autogenous fibular strut graft as revision surgery was performed on seven patients: four patients having disorders of adjacent discs after anterior discectomy and fusion and three patients having postlaminoplasty disorders. Japanese Orthopedic Association scores (JOA scores) of the cervical myelopathy and severity of radicular and axial pains were used to evaluate outcomes. RESULTS: Rigid osseous fusion was achieved in all patients. JOA scores of the cervical myelopathy and the radicular pain, which had worsened just before the revision surgery, were improved significantly. CONCLUSION: In the present seven patients who had variety of pathological conditions with various previous surgeries, multilevel ACF using strut graft was effective as a revision procedure in ameliorating their symptoms.

Abstract: STUDY DESIGN: We report a successful extensive transoral anterior decompression for an elderly patient with myelopathy and occipitalgia due to severe atlantoaxial vertical subluxation and posterior subluxation of the axis associated with rheumatoid arthritis (RA). OBJECTIVE: To describe the treatment of an exceptional pathological condition involving severe vertical subluxation. SETTING: University-affiliated hospital in Gifu, Japan. METHODS: A 73-year-old woman was referred to our clinic because of myelopathy and occipitalgia due to severe atlantoaxial vertical subluxation and posterior subluxation of the axis associated with RA. Plain radiographs revealed severe atlantoaxial vertical subluxation and sagittal magnetic resonance (MR) imaging revealed severe compression of the spinal cord at the level of the C2/3 disc space due to both posterior subluxation of C2 and rheumatoid pannus at the C2/3 disc space. As MR images demonstrated that the C2/3 disc space was located just behind the retropharyngeal wall, we performed successful anterior decompression from C2 to C3 via the standard transoral approach without mandibular osteotomy. RESULTS: The patient has been followed for 4 years and her symptoms are currently much improved without further surgical treatment. CONCLUSIONS: The present case illustrates that severe atlantoaxial vertical subluxation and posterior subluxation of the axis associated with RA can be treated successfully by anterior decompression of C2 and C3 via the standard transoral approach.

Abstract: INTRODUCTION: The treatment of methicillin-resistant Staphylococcus aureus (MRSA) spondylodiscitis is reported to be far more difficult than that of non-MRSA spondylodiscitis. At present, there seems to be no standard protocol for the treatment of MRSA spondylodiscitis cases in which conservative management has failed. MATERIALS AND METHODS: Between 1998 and 2001, five patients (aged 48-73 years; average: 63.8 years; SD: 9.9) with MRSA spondylodiscitis were treated surgically after conservative treatment had failed. Posterior spinal instrumentation was performed for all five patients, three of whom also underwent anterior debridement and bone graft. All the patients had neurological deficits and severe pain. To assess the invasiveness of the operation, we evaluated operating time, blood loss, and complications. Pain (verbal rating scale; VRS), neurological status (Frankel type), activities of daily living (ADL) (the Barthel index), WBC, CRP, and ESR in the preoperative, postoperative and final follow-up periods were used to evaluate the surgical outcomes. RESULTS: Although we encountered several postoperative complications including deep wound infections, at the final follow-up visit, the neurological deficits, activities of daily living, Barthel index, and VRS had improved in all the patients. Changes in WBC, CRP, and ESR revealed suppression of infection in all patients. CONCLUSION: Surgical treatment for MRSA spondylodiscitis with posterior spinal instrumentation provided patients with satisfactory final outcomes.

Abstract:

Abstract: BACKGROUND CONTEXT: Using biochemical, histological, and radiological parameters in a rabbit model of intervertebral disc (IVD) degeneration, the intradiscal injection of a growth factor, such as osteogenic protein-1 (OP-1), has been shown to regenerate the IVD. However, very little is known about how such a biological therapeutic approach affects the biomechanical properties of the degenerated IVD. PURPOSE: To investigate the effects of an intradiscal injection of OP-1 on the biomechanical properties of IVDs in the rabbit annular-puncture disc degeneration model and to determine their relationship to biochemical properties. STUDY DESIGN/SETTING: In vivo study on the effects of intradiscally administered OP-1 on the biomechanical and biochemical properties of IVDs in the rabbit annular-puncture disc degeneration model. METHODS: New Zealand White rabbits (n=16) underwent annulus fibrosus (AF) puncture, using an 18-gauge needle, at L2-L3 and L4-L5 (L3-L4: nonpunctured control). Four weeks later, the punctured discs received an injection of either 5% lactose (10 microL) or OP-1 (100 microg/10 microL of 5% lactose) into the nucleus pulposus (NP). The disc height was radiographically monitored biweekly. After sacrifice and removal of bone-disc-bone complexes 8 weeks postinjection, the dynamic viscoelastic properties of the IVDs were tested by applying a cycle of sinusoidal strain in uniaxial compression at six loading frequencies (0.05 to 2 Hz). The biochemical properties of the dissected IVDs were then analyzed and correlated with the biomechanical properties. RESULTS: A single injection of OP-1 significantly restored disc height when compared with the lactose-injected discs (OP-1 vs. lactose, p<.001). The elastic modulus of the IVDs in the OP-1-injected discs was significantly higher than that in the lactose-injected discs at all frequencies (mean: +43%, p<.001). The viscous modulus in the OP-1-injected discs was significantly higher at 0.05, 0.2, 0.5, and 1 Hz (mean: +55%, p<.001) and showed higher tendencies at other frequencies (p=.08-.09). For both moduli, no significant differences were observed between the OP-1-injected and the nonpunctured control discs. The OP-1 injection significantly increased the proteoglycan (PG) content in the NP and AF, and the collagen content in the NP (p<.001-.05). Both elastic and viscous moduli showed significant positive correlations with PG content in the NP and collagen content in the NP and AF (Rho=.357-.466, p=.010-.047). CONCLUSIONS: We have shown for the first time that an injection of the growth factor, OP-1, restored the biomechanical properties of IVDs in a rabbit model of IVD degeneration. Comparing biomechanical with biochemical data suggests that the OP-1-induced biomechanical restoration was a consequence of increased activities of anabolic pathways that resulted in biochemical changes in the IVD.

Abstract: STUDY DESIGN: An in vivo study on the effects of an agent for scar prevention in a dog laminectomy model. OBJECTIVE: To examine the anti-adhesion properties of a thrombin-based hemostatic gelatin (FLOSEAL; Baxter International Inc., Deerfield, IL). SUMMARY OF BACKGROUND DATA: Postlaminectomy dural adhesion sometimes causes symptomatic problems. Although a new type of hemostatic agent, a thrombin-based hemostatic gelatin, has been developed, its effect on postlaminectomy scar prevention is unknown. METHODS: A 4-level lumbar laminectomy was performed on 11 adult mongrel dogs. There were 2 levels randomly chosen to receive the thrombin-based hemostatic gelatin treatment, while the remaining levels were untreated (control). Dogs were euthanized 8 weeks after surgery. To assess the tenacity of adhesion between the dura and scar, peel-off testing was performed. Gross, biochemical, and histologic analyses were then used to examine the samples. RESULTS: Peel-off stiffness was significantly decreased in the treatment group (64.8% of the control, P = 0.032; 2-tailed unpaired t test). Histologically, there was significantly less scar tissue formation in the treatment group (P = 0.04). The gross analyses showed a trend toward a smaller amount of scar tissue and tenacity of adhesion between the dura and scar in the treatment group. Biochemically, there was a trend toward a lower collagen cross-links content in the treatment group (P = 0.07). CONCLUSIONS: The thrombin-based hemostatic gelatin decreases the tenacity of adhesion between the dura and scar at laminectomy sites.

Abstract: STUDY DESIGN: This is a report of a 12-year-old girl treated surgically for scoliosis associated with bilateral hip dislocation in Larsen syndrome. OBJECTIVE: To describe a rare case of scoliosis associated with Larsen syndrome and bilateral hip dislocation that was treated surgically with follow-up for 15 years. SUMMARY OF BACKGROUND DATA: There are few reports of the long-term follow-up of cases involving surgically treated scoliosis associated with bilaterally dislocated hips. METHODS: The patient's spine showed a right thoracic curve (T5-T12) with a Cobb angle of 77 degrees and did not show pelvic obliquity on an anterior-posterior radiograph film. On the sagittal alignment of her spine, the thoracic spine showed an abnormal lordosis (T5-T12: 19 degrees), and the lumbar spine had a hyperlordosis (L1-S1: 57 degrees) with a large lumbosacral angle (72 degrees ). We performed a posterior spinal fusion between T4 and L2 using Cotrel-Dubousset Instrumentation, anticipating the restoration of normal lumbar and cervical lordosis, as well as thoracic kyphosis. RESULTS: The Cobb angle of thoracic scoliosis improved from 77 degrees to 28 degrees, and a thoracic kyphosis of 12 degrees (T5-T12) was obtained. Subsequently, on the sagittal plane, the lumbosacral angle (sacral anteflexion) decreased from 72 degrees to 52 degrees, comparable to that of patients with hip dislocation, and the lumbar lordotic angle increased from 57 degrees to 66 degrees. The restoration of thoracic kyphosis resulted in an increase of lumbar lordosis and decrease of sacral anteflexion. At the 15-year follow-up,although the thoracic scoliosis (T5-T12) had increased to 36 degrees, good coronal and sagittal balance had been maintained. The patient is asymptomatic in her spine and hip. CONCLUSIONS: A case of scoliosis associated with dislocated hips in a patient with Larsen syndrome was successfully treated with posterior correction surgery. Fusion surgery between T4 and L2 provided an ideal sagittal balance of the total spine, while preserving 4 lumbar mobile segments.

Abstract: STUDY DESIGN: In vitro studies on the effects of recombinant human growth and differentiation factor-5 (rhGDF-5) on matrix metabolism of bovine intervertebral disc cells and an in vivo study on the effect of rhGDF-5 in the rabbit anular puncture model. OBJECTIVE: To determine the reparative capacity of rhGDF-5 on the intervertebral disc. SUMMARY OF BACKGROUND DATA: The in vitro and in vivo effects of rhGDF-5, a crucial protein in the developing musculoskeletal system, on repair of the degenerated intervertebral disc remain unidentified. METHODS: In vitro, bovine nucleus pulposus and anulus fibrosus cells were cultured with or without rhGDF-5 (100 or 200 ng/mL). On days 7, 14, and 21, the contents of deoxyribonucleic acid and proteoglycan, and the synthesis of proteoglycan and collagen were assessed. In vivo, 16 adolescent New Zealand white rabbits received anular punctures in 2 lumbar discs. Four weeks later, phosphate buffered saline or rhGDF-5 (10 ng, 1 and 100 mug) was injected into the nucleus pulposus. The rabbits were followed up for 16 weeks for disc height, magnetic resonance imaging, and histologic grading. RESULTS: In vitro, rhGDF-5 increased the deoxyribonucleic acid and proteoglycan contents of both cell types significantly after day 14. rhGDF-5 at 200 ng/mL significantly stimulated proteoglycan synthesis (nucleus pulposus: +138%, anulus fibrosus: +24%) and collagen synthesis (nucleus pulposus: +95%, anulus fibrosus: +23%) at day 21. In vivo, the injection of rhGDF-5 resulted in a restoration of disc height, improvement of magnetic resonance imaging scores, and histologic grading scores with statistical significance (P < 0.05-0.001). CONCLUSION: A single injection of rhGDF-5 has a reparative capacity on intervertebral discs, presumably based on its effects to enhance extracellular matrix production in vitro.

Abstract: We report a displaced femoral shaft fracture that occurred with no sign of contact-induced, stress, fatigue, or previous abnormal bone pathology in a 19-y-old man who kicked the ground instead of the ball when playing soccer. After examination to rule out abnormal bone pathology, intramedullary nailing was performed. Bone union was achieved and he could return to recreational soccer. Among soccer injuries, the occurrence of displaced femoral shaft fractures in the absence of stress, fatigue, or pathological fracture is rare. Awareness of such a rare cause of displaced femoral shaft fracture would help clinicians in the field of sports and soccer medicine.

Abstract: BACKGROUND CONTEXT: A case of spondyloepiphyseal dysplasia congenita (SEDC) with thoracolumbar kyphosing scoliosis and a clinical outcome of the patient's surgical treatment are reported. PURPOSE: We report a rare case and the effect of surgical treatment on the kyphosing scoliosis with SEDC with a review of literature. STUDY DESIGN/SETTING: SEDC is a rare disease and has a variety of spinal deformities. To our knowledge, a case of surgical treatment for the kyphosing scoliosis with SEDC was not reported before. METHODS: The patient, a 27-year-old woman, complained of severe back pain and dyspnea. She was operated on in 1997 for severe kyphosing scoliosis, using segmental spinal instrumentation and strut bypass graft. She was followed for 6 years, and clinical symptoms and plain X-ray films were investigated. RESULTS: Her kyphosis was corrected from 116 degrees to 86 degrees at the final follow-up; otherwise, her scoliosis was almost unchanged. Her symptoms were relieved. CONCLUSIONS: A case of SEDC with thoracolumbar kyphosing scoliosis was successfully treated by segmental spinal instrumentation and anterior strut bypass graft.

Abstract: STUDY DESIGN: The effects of a halo vest on the gait were studied. The motions of the head, shoulder girdle, trunk, and hip were analyzed with the vest and tong either connected by bars or unconnected. OBJECTIVE: To analyze effects of wearing a halo vest using three-dimensional motion analysis. SUMMARY OF BACKGROUND DATA: We have little information on the effects of halo vests on gait. METHODS: Twenty-eight healthy male volunteers participated (age, 32 +/- 7.2; average +/- SD). The halo tong and vest were applied in a noninvasive way. Gait patterns and three-dimensional motions of the head, shoulder girdle, trunk, pelvis, and hip in control and halo vest gaits were analyzed using rectangular force plates and a VICON system (Vicon Motion System Ltd., Oxford, UK). RESULTS: The halo vest decreased the gait speed; it increased the duration of strides and decreased the length of strides. It also decreased the motions between the shoulder girdle and the trunk, the trunk and the pelvis, and decreased the motion of the hip in 3 planes. CONCLUSION: Our study provides preliminary evidence that halo vests increase stride time and decrease stride length and reduce motions between the shoulder girdle and the trunk, the trunk and the pelvis, and decreases the motion of the hip.

Abstract: Cervical vertebral involvement of clear cell meningioma is very rare. We report a case of clear cell meningioma in the cervical vertebral body in a 72-year old male. Seven years prior to this presentation, the patient underwent palliative surgery and posterior instrumentation for a cervical vertebral tumor at C5, which had been diagnosed as a metastatic renal cell carcinoma. On this admission, the patient presented with severe neck pain. Examination revealed hypesthesia on the left in a C6 nerve root distribution. Plain X-rays and MRI revealed an enlarging tumor in the C5 and C6 vertebral bodies. The tumor was resected via an anterior approach followed by fusion using a strut bone graft. Histological examination of the surgical specimen diagnosed a clear cell meningioma. Postoperatively, the patient achieved pain relief and resolution of the neurological deficit. At follow-up two years postoperatively, he remains asymptomatic. We emphasize that cervical clear cell meningioma with involvement of the vertebral bodies may mimic metastatic renal cell carcinoma.

Abstract: BACKGROUND CONTEXT: Although posterior lumbar interbody fusion (PLIF) for degenerative lumbar diseases is routine, there are few reports on double-level PLIF. PURPOSE: To evaluate the clinical outcomes of double-level PLIF. STUDY DESIGN/SETTING: A retrospective study of operated cases in Gifu, Japan. PATIENT SAMPLE: Nineteen patients (8 men and 11 women, 59.5+/-10.2 years) who underwent double-level PLIF between 1996 and 2001. OUTCOME MEASURES: Operation time, blood loss, complications, the Japanese Orthopaedic Association (JOA) score for back pain and lumbar sagittal alignment were evaluated. METHODS: Patients were examined retrospectively at follow-ups of 3.6+/-1.7 years. Primary diseases were spondylolisthesis, spinal canal stenosis, degenerative scoliosis and herniated intervertebral disc. Fusion areas were L3 to L5 in 15 cases and L4 to S1 in 4 cases. RESULTS: The mean JOA score increased from an initial score of 12.9+/-3.5 to 21.3+/-4.9 at the final follow-up. There was a positive correlation (R=0.718, p<.001) between the increase in lordotic angle and the increase in the JOA score. Several parameters suggested that the surgical invasiveness was not minimal. CONCLUSION: Double-level PLIF provided satisfactory results and preserved lumbar spine lordosis.

Abstract: Multiple thoracic disc herniations are rare and there are few reports in the literature. Between December 1998 and July 2002, we operated on 12 patients with multiple thoracic disc herniations. All underwent an anterior decompression and fusion through a transthoracic approach. The clinical outcomes were assessed using the Frankel neurological classification and the Japanese Orthopaedic Association (JOA) score. Under the Frankel classification, two patients improved by two grades (C to E), one patient improved by one grade (C to D), while nine patients who had been classified as grade D did not change. The JOA scores improved significantly after surgery with a mean recovery rate of 44.8% +/- 24.5%. Overall, clinical outcomes were excellent in two patients, good in two, fair in six and unchanged in two. Our results indicate that anterior decompression and fusion for multiple thoracic disc herniations through a transthoracic approach can provide satisfactory results.

Abstract:

Abstract: STUDY DESIGN: Report of a rare case of an elderly patient with late onset of Arnold Chiari malformation type I with associated syringomyelia that was successfully treated with foramen magnum decompression. OBJECTIVE: To report this rare case along with a literature review. SETTING: Gifu, Japan. METHODS: A 69-year-old woman with a 4-year history of dull pain in her right arm was referred to the clinic. After physical and radiographical examinations, she was diagnosed with Arnold Chiari malformation type I with associated syringomyelia. A foramen magnum decompression by the removal of the outer layer of the dura mater was performed. RESULTS: At 2 years postoperatively, MRI revealed a decrease in the size of the syringomyelia. Her symptoms had also remarkably improved. CONCLUSIONS: A rare case of symptomatic Arnold Chiari malformation type I with associated syringomyelia in an elderly woman was successfully treated with foramen magnum decompression by the removal of the outer layer of the dura mater.

Abstract: The present study was performed to evaluate the effects of erector spinae muscle fatigue on trunk repositioning accuracy. Trunk repositioning accuracy in forward and lateral flexion was measured in 25 healthy men using a 3-Space Fastrak (Polhemus Inc., Colchester, VT, USA) with a transmitter on the sacrum and a sensor on Th9. The subjects reproduced 1/3, 1/2, and 2/3 maximum forward and lateral flexion angle of the trunk before and immediately after fatiguing of the erector spinae muscle by repetitive maximum isokinetic trunk exertion. Average trunk repositioning errors in all the positions were measured. The results indicated that, in both forward and lateral flexion, the trunk repositioning error was significantly (p<0.05) greater after the fatiguing procedure than under normal conditions (paired t-test). In conclusion, fatigue of the erector spinae muscles significantly decreases the trunk repositioning accuracy in both forward and lateral flexion.

Abstract: STUDY DESIGN: Case report of a severe upper cervical cord compression and tetraparesis by a massive cervical exostotic osteochondroma in a patient with multiple exostoses-mental retardation syndrome (Langer-Giedion syndrome; LGS). OBJECTIVE: To describe this very rare pathological condition and the results of surgical intervention. SETTING: Gifu, Japan. METHODS: A 23-year-old man was referred to our clinic because of progressing tetraparesis. He had previously been diagnosed with hereditary multiple exostoses and mental retardation. As he had not complained of any symptoms, his family only noticed the tetraparesis after advanced deterioration. His face possessed the pathognomic features of LGS. A postmyelogram CT scan demonstrated an exostotic mass arising from the left-side C2 pedicle with associated severe spinal cord compression. He was diagnosed with LGS. Hemilaminectomy on the left side and resection of the osteochondroma were performed. RESULTS: At 5 years postoperatively, a neurological examination showed the full return of all motor functions. The CT scan revealed no intracanalar recurrence of the tumor. CONCLUSION: In this case of severe tetraparesis due to cervical osteochondroma, decompression by hemilaminectomy provided excellent results. In patients with LGS and intracanalar osteochondroma, the neurological deficit may be masked by mental retardation. Hence, awareness of this pathological condition will help clinicians diagnose it at an early stage.

Abstract: BACKGROUND: There is little information about the relationship between the changes of hemodynamics and the morphologic changes of the erector spinae muscle. METHODS: Fifty healthy male volunteers participated. Ultrasonography was used to measure muscle thickness, and near-infrared spectroscopy was used to measure tissue blood volume and its oxygenation in the erector spinae muscle at L3 in six different relaxed trunk postures (flexed 20 degrees , flexed 40 degrees, flexed maximum, neutral posture, extended 20 degrees, and extended maximum of the lumbar spine). We also evaluated the reproducibility of the near-infrared spectroscopy measurements. FINDINGS: Near-infrared spectroscopy gave highly reproducible measurements. The thickness of the erector spinae muscle and the total and oxygenated hemoglobin were simultaneously increased during relaxed extension and decreased during relaxed flexion. Changes in the thickness of the erector spinae muscle with various lumbar curvature were similar in pattern to the changes in tissue blood volume and its oxygenation. INTERPRETATION: The erector spinae muscles' thickness, tissue blood volume, and its oxygenation are simultaneously increased during relaxed extension and decreased during relaxed flexion, as demonstrated by non-invasive near-infrared spectroscopy and ultrasonography. These findings might afford a better understanding of the pathomechanics of posture-related back symptoms. RELEVANCE: The erector spinae muscles' thickness, tissue blood volume, and its oxygenation are simultaneously increased during relaxed extension and decreased during relaxed flexion, as shown by non-invasive near-infrared spectroscopy and ultrasonography. Changes in hemodynamics and morphology of the erector spinae muscles in asymptomatic subjects are given for further research on the pathomechanism of back pain.

Abstract: STUDY DESIGN: In vitro study on the effects of pulsed low intensity ultrasound on the cellular metabolism of bovine intervertebral disc cells. OBJECTIVE: To determine whether pulsed low intensity ultrasound has effects on cell proliferation and extracellular matrix metabolism by bovine intervertebral disc cells. SUMMARY OF BACKGROUND DATA: The application of pulsed low intensity ultrasound is known to be effective in stimulating fracture and cartilage repair. However, the effects of pulsed low intensity ultrasound on intervertebral disc cells are not known. METHODS: Cells of the nucleus pulposus and inner and outer anulus fibrosus were enzymatically isolated from bovine coccygeal tissue and precultured in alginate beads for 14 days. In the ultrasound group, pulsed low intensity ultrasound was administered to the culture for 20 minutes daily for an additional 20 days. The control group was cultured in the same way but without administration of ultrasound. Cell viability, DNA content, proteoglycan and collagen synthesis, and proteoglycan content at days 10 and 20 after the initiation of treatment were evaluated. Characterization of newly synthesized collagen and proteoglycan was performed. RESULTS: No significant differences in cell viability and DNA content were observed between the two groups. On day 20, proteoglycan synthesis was increased by the application of pulsed low intensity ultrasound in nucleus pulposus and inner and outer anulus fibrosus cells (24%-26% increase, P < 0.001). The application of pulsed low intensity ultrasound increased proteoglycan content in alginate beads containing inner and outer anulus fibrosus cells (P < 0.05). Collagen synthesis by cells isolated from all three zones of the intervertebral disc was increased by the application of pulsed low intensity ultrasound (16%-19% increase, P < 0.05-0.0001). CONCLUSIONS: The application of pulsed low intensity ultrasound stimulated extracellular matrix metabolism in intervertebral disc cells. Pulsed low intensity ultrasound may prove useful for the physical stimulation of cell metabolism for tissue engineering of intervertebral disc tissue.

Abstract: The surgical outcomes of 13 patients who were diagnosed with cervical spondylotic myelopathy were reviewed retrospectively. Mean patient age at surgery was 83 years. The severity of cervical spondylotic myelopathy was evaluated using the Japanese Orthopaedic Association score. Daily activities were evaluated using the Barthel index. The preoperative JOA score and Barthel index were 7.8 and 63.5, respectively. The mean JOA score and Barthel index maximum recovery rate were 35% and 24%, respectively. The results of this study imply that surgery for patients with cervical spondylotic myelopathy aged > 80 years is warranted.

Abstract: STUDY DESIGN: Case report of a solitary fibrous tumor in the occipitocervical region. OBJECTIVE: To describe a rare clinical entity and successful management in a patient with solitary fibrous tumor in the occipitocervical region. SUMMARY OF BACKGROUND DATA: Solitary fibrous tumor is a rare spindle cell neoplasm of adults that arises most commonly in the pleura. Recently, this tumor has been reported in a number of other sites. However, its occurrence in the occipitocervical region is rare. METHODS: The patient presented with a painless mass in the left posterior neck. Resection of the tumor was performed. RESULTS: Histopathological study revealed features of a solitary fibrous tumor. Clinical follow-up review for 2.5 years shows no evidence of recurrence or metastasis. CONCLUSION: A case of extrapleural solitary fibrous tumor in the occipitocervical region was reported. Solitary fibrous tumor should be considered in the differential diagnosis in a tumoral mass of this region.

Abstract: We report a case of an 80-year-old woman with dropped head syndrome associated with cervical spondylotic myelopathy. She could not keep her cervical spine in a neutral position for >1 minute. She had a disturbed gait and severe kyphotic deformity in her thoracic spine. Magnetic resonance imaging revealed severe compression of the spinal cord due to cervical spondylotic change. Laminoplasty from C2 through C6 levels was performed. One year after operation, she could keep her cervical spine in a neutral position easily. Her gait was also improved. The symptoms did not recur during 4 years of follow-up. We surmise that to maintain daily activities, she had to extend her cervical spine owing to the thoracic kyphotic deformity, resulting in compression of the spinal cord. The compression led to weakening of the cervical extensor muscles. Cervical laminoplasty was effective.

Abstract: AIM: We investigated the association of habitual long-distance running with the thickness of skeletal muscles and subcutaneous fat in the body extremities and trunk in middle-aged men using ultrasonography. METHODS: Three groups of healthy middle-aged men [mean (SD), 62.1 (2.8) years] took part in this investigation: a high-level group of 11 master runners who had competed in a 42.195 km race and run 51.6 (21.7) km every week, an intermediary-level group of 10 master runners who had competed in a 5-20 km race and run 9.3 (4.9) km every week, and a low-level group of 7 untrained men who continued to do no systematic training. The muscle thickness at 8 sites and the subcutaneous fat thickness at 10 sites were measured by B-mode ultrasonography, and were compared among the 3 groups. RESULTS: The high-level group had 10.0(-1)5.2% higher values for muscle thickness at the erector spinae, hamstrings, tibialis anterior, and triceps surae, compared with the intermediary-level and the low-level groups (p<0.05-0.001). The thickness of the subcutaneous fat about the rectus abdominis and external oblique was lower in the high-level group than in the intermediary-level and the low-level groups (p<0.05). CONCLUSIONS: Middle-aged male master athletes who habitually run at a high level have more muscle thickness in the lower extremities and trunk, and less subcutaneous fat thickness in the central regions of the body than do middle-aged men who habitually run at an intermediary level or do not run at all.

Abstract: The purpose of this study was to quantitatively evaluate spontaneous body sway during maximum grasping maneuver with a hand dynamometer, which we sometimes encounter in clinical practice. The postural reaction of the whole body during maximum grasping maneuver was analyzed in 26 right-handed healthy male volunteers using a three-dimensional motion analysis system (VICON system, Oxford Metrics, UK) and force plates. We found that the gravity center of the body moved toward the grasping side. Also, voluntary rotation of the trunk and flexion of the neck was observed during grasping on each side.

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Abstract: STUDY DESIGN: An observational study of the changes in thickness of the erector spinae (ES) muscle in three different trunk postures. OBJECTIVE: To use ultrasonography to evaluate the thickness of the ES muscle in three different trunk postures. BACKGROUND: Although there has been extensive study of the morphology of the ES muscle during prolonged trunk flexion, we have little information about the changes in thickness of these muscles in various postures of the lumbar spine. Ultrasonography has never been used to measure the thickness of ES muscle. METHODS: We studied 30 volunteers with no history of lower back problems. We used ultrasonography to measure the thickness of the ES muscle at each lumbar level (L1, L2, L3, L4, and L5) in maximum flexion, neutral posture, and maximum extension. We tested the reliability of this method by evaluating intraobserver and interobserver differences in 13 subjects. RESULT: The high correlation between intraobserver and interobserver measurements in the 13 subjects demonstrated that the method provides sufficient reproducibility. When the trunk was flexed maximally, the thickness of the ES muscle was significantly decreased at each lumbar vertebral level. When the trunk was extended maximally, the thickness of the ES muscle was significantly increased at each lumbar vertebral level. CONCLUSION: The thickness of the ES muscle decreases as the lumbar spine flexes and increases as it extends. We used ultrasonography successfully for quantitative evaluation of changes in thickness of the ES muscle with postural changes in the lumbar spine.

Abstract: The authors discuss the cases of three patients in whom thoracic paraplegia developed after lumbar spinal decompressive surgery for slight lumbar spinal canal stenosis. Careful computerized tomography myelography and magnetic resonance imaging examination of the thoracic spine revealed another compressive lesion (spinal cord tumor, disc herniation, osteophyte of vertebral body, and ossification of the ligamentum flavum). Additional thoracic decompressive surgery provided partial amelioration of each patient's neurological condition. The authors suggest that to avoid such a complication physical and radiographic examination of the thoracic spine should be performed preoperatively if the lumbar imaging is inconclusive.

Abstract: BACKGROUND: Although segmental wire fixation has been successful in the treatment of nonathletes with spondylolysis, no information exists on the results of this type of surgery in athletes. PURPOSE: To evaluate the outcome of surgical repair of pars interarticularis defect by segmental wire fixation in young athletes with lumbar spondylolysis. METHODS: Between 1993 and 2000, 20 athletes (6 women and 14 men; average age, 23.7) with lumbar spondylolysis were treated surgically with this technique. They were actively engaged in sports such as baseball, tennis, and golf. Nineteen athletes had one level of spondylolysis and one athlete had two levels. The level of spondylolysis was L4 in 2 athletes and L5 in 19. The average follow-up period was 3.5 years (range, 1.3 to 8.6). Surgical outcome was evaluated by radiographic examination, the Japanese Orthopaedic Association score, preoperative and postoperative sports activity levels and intensities, and the presence of complications. RESULTS: Bony fusion at the site of spondylolysis was obtained in all cases, and the Japanese Orthopaedic Association score was increased significantly after surgery (preoperatively, 21.2 +/- 3.9; postoperatively, maximum 27.7 +/- 1.0; recovery rate, 80.4%). All of the patients returned to their sports activities, although at varying degrees. No severe complications were noted. CONCLUSION: We recommend this technique in cases of lumbar spondylolysis in athletes who hope to resume their sports activities.

Abstract: STUDY DESIGN: We report on a 69-year-old male who had severe back pain due to spontaneous symptomatic pseudoarthrosis at the T11-T12 intervertebral space with diffuse idiopathic skeletal hyperostosis. OBJECTIVE: To describe a rare clinical entity and successful treatment by spinal fusion with a 4-year follow-up. SUMMARY OF BACKGROUND DATA: There have been a few reports of spontaneous symptomatic pseudoarthrosis of an intervertebral space associated with diffuse idiopathic skeletal hyperostosis, but there have been no reports of surgical treatment for this clinical condition. METHODS: Plain radiographs of the patient, who was admitted to our hospital with severe back pain but no history of trauma, revealed manifestations of diffuse idiopathic skeletal hyperostosis and a pseudoarthrosis at the T11-T12 intervertebral space. Posterior instrumentation from T9 to L2 and anterior bone grafting at the T11-T12 intervertebral space were performed. RESULTS: The patient has been followed for 4 years and is currently asymptomatic. CONCLUSIONS: A rare case of spontaneous symptomatic pseudoarthrosis at the T11-T12 intervertebral space with diffuse idiopathic skeletal hyperostosis was treated successfully by spinal fusion.

Abstract: STUDY DESIGN: A retrospective analysis was performed of the clinical outcomes of patients with pyogenic or tuberculotic spondylitis who were treated with two-stage surgery (first stage: placement of posterior instrumentation; second stage: anterior debridement and bone grafting). OBJECTIVE: To evaluate the clinical outcomes of the abovementioned two-stage surgical treatment for pyogenic or tuberculotic spondylitis. SUMMARY OF BACKGROUND DATA: Although several methods of surgical treatment for pyogenic and tuberculotic spondylitis have been reported, there have been few reports of two-stage surgical treatment. METHODS: Eight patients (7 male, 1 female) with pyogenic or tuberculotic spondylitis (pyogenic: 6; tuberculotic: 2) were treated by two-stage surgery (first: placement of posterior instrumentation, second: anterior debridement and bone graft). Age at the time of surgery was 63.5 +/- 9.91 years (average +/- SD) (range: 47 to 77 years). Most of the patients had systemic problems, such as pneumonia, diabetes mellitus, or chronic renal failure. First, posterior spinal instrumentation was placed. Then, anterior debridement and bone grafting were performed. Patients were evaluated before and after surgery in terms of pain level, hematologic parameters, neurologic status, and Barthel index. RESULTS: Average duration of surgery for both procedures was less than 4 hours. Changes in the pain level, blood parameters, and Barthel index demonstrated significant clinical improvement in all patients. Posterior wound infection occurred in two patients who were in poor general condition. CONCLUSIONS: This two-stage surgical treatment for pyogenic or tuberculotic spondylitis provided satisfactory results and can also be used in patients who are in poor general condition.

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Abstract: STUDY DESIGN: This study was designed to validate a translated version of the Roland-Morris Disability Questionnaire (RMDQ). OBJECTIVE: To validate the Japanese version of the RMDQ (JRMDQ) for Japanese patients with low back pain (LBP) and/or lumbar spinal diseases (LD). SUMMARY OF BACKGROUND DATA: To assess the effect of interventions, a scale that directly assesses disabilities in patients with LBP and/or LD and that can be used internationally needs to be established in Japan. MATERIALS AND METHODS: To promote the JRMDQ, the RMDQ was translated into Japanese and then back-translated. In four hospitals, 320 patients with LBP and/or LD were examined. At first, they were examined using the JRMDQ, the Japanese Orthopedic Association (JOA) score, and the visual analogue scale (VAS). The repeatability of the JRMDQ was evaluated in 55 patients by two examinations within 2 weeks. To examine the validity of the JRMDQ, the correlation between the JRMDQ and other scales was calculated in all 320 patients. RESULTS: The JRMDQ demonstrated significant repeatability (R = 0.810, P < 0.0001). The JRMDQ and other scales demonstrated significant correlations (JRMDQ-JOA, R = -0.772; JRMDQ-ADL items of JOA score, R = -0.790; JRMDQ-VAS, R = 0.447, P < 0.0001). CONCLUSIONS: The JRMDQ is a repeatable and valid questionnaire for assessing disabilities caused by LBP and/or LD. The JRMDQ is equivalent to the English RMDQ.

Abstract: STUDY DESIGN: This study focused on the effects of leg length discrepancy on the motion of the normal spine during gait in healthy male volunteers who wore a heel-raising orthotic device on the right foot. OBJECTIVE: To evaluate the effect of leg length discrepancy on the changes in curvature of the normal spine during gait. SUMMARY OF BACKGROUND DATA: There are few published data on the effects of leg length discrepancy on the motion of the normal spine during gait. METHODS: An orthotic device that raised the heel by 3 cm was used to simulate leg length discrepancy. Twenty-two healthy male volunteers participated (age: 28.2 +/- 6.1 years, average +/- SD). The dynamic curvatures of the spine under two conditions (without and with a heel-raising orthotic device; normal gait and heel-raising gait) were evaluated during gait. The leg length discrepancy values without and with the device were measured and analyzed using a VICON system (Oxford Metrics, United Kingdom). RESULTS: The spine showed an asymmetrical lateral-bending motion during heel-raising gait as compensation for the leg length discrepancy. Maximum lateral bending angle of the thoracic spine was 4.2 +/- 1.4 degrees in heel-raising gait, whereas it was 3.0 +/- 1.0 degrees in normal gait. Maximum lateral bending angle of the lumbar spine was 8.1 +/- 2.8 degrees in heel-raising gait, whereas it was 6.1 +/- 2.1 degrees in normal gait. The maximum bending angle and bending velocity were significantly larger in the heel-raising gait than in normal gait. CONCLUSION: Patients who have leg length discrepancy due to disorders in the lower extremities are at greater risk of developing disabling spinal disorders due to exaggerated degenerative change. Therefore, treatment for leg length discrepancy may be helpful in preventing degenerative spinal changes.

Abstract: STUDY DESIGN: Report of a case of subarachnoid hematoma associated with neurofibromatosis type 2 (NF2) in a 10-year-old girl. OBJECTIVE: To report a rare case of subarachnoid spontaneous hematoma associated with NF2, with no evidence of trauma. SETTING: Gifu, Japan. METHODS: The patient presented with severe leg pain. MRI revealed a subarachnoid hematoma at the level of L2 and a spinal cord tumor at the level of T6. The subarachnoid hematoma had low and high heterogeneous signal intensity on the T1-weighted image and low signal intensity on the T2-weighted image, indicating the presence of extracellular methemoglobin. The tumor and hematoma were resected. RESULTS: Pathological analysis demonstrated that the surgical specimen removed from the area of L2 was a hematoma and the specimen from T6 was a neurinoma. At follow-up 1 year after surgery, the girl remained neurologically asymptomatic. CONCLUSIONS: This rare case of spinal subarachnoid hematoma was associated with NF2. MRI was useful in establishing the diagnosis.

Abstract: STUDY DESIGN: A 9-year-old boy with severe myelomeningocele kyphosis was treated by kyphectomy using a surgical threadwire. OBJECTIVE: To describe a new method of kyphectomy for severe kyphotic deformity in a child with myelomeningocele using a surgical threadwire. SUMMARY OF BACKGROUND DATA: Although several methods of kyphectomy for severe kyphotic deformity in children with myelomeningocele have been reported, few of these methods allow preservation of the nonfunctioning dural sac and cerebrospinal fluid flow, with the aim of reducing complications. METHODS: The preoperative kyphotic angle was 113 degrees. There was repeated skin ulceration over the apex of the kyphos. Kyphectomy at the Th12 to L3 vertebral levels was performed using a surgical threadwire (T-saw, developed by Tomita and colleagues in 1996), preserving the entire dural sac. RESULTS: The T-saw allowed anterior dissection of the dural sac over the length of the planned resection, thus preserving cerebrospinal fluid flow throughout the entire subarachnoid space. The kyphotic angle was decreased to 10 degrees after the operation, and the postoperative clinical course was uneventful. At the 2-year follow-up assessment, the kyphotic angle was 10 degrees according to plain radiograph. At this writing, the boy is able to maintain a sitting position without any difficulty. CONCLUSIONS: For this child with myelomeningocele, kyphectomy using a surgical threadwire (T-saw) provided a satisfactory result without any major complication.

Abstract: We report a case of atlantoaxial vertical subluxation with mandibular micrognathia associated with juvenile rheumatoid arthritis. The patient was treated by odontoidectomy via the transoral approach and required a sagittal split mandibular osteotomy because of the mandibular micrognathia. The clinical outcome was excellent.

Abstract: STUDY DESIGN: Case report of a rare form of hypertrophy of the thoracic posterior longitudinal ligament (HPLL), causing paraparesis. OBJECTIVE: To describe this very rare pathological condition in the thoracic spine and the results of surgical intervention. SETTING: A department of orthopaedic surgery in Japan. METHODS: A 61-year-old man presented with acute paraparesis associated with HPLL in the thoracic region. A radiographic and pathological review of the case was conducted. Anterior decompression was performed, and he was followed for 3 years after the operation. RESULTS: Pathologic examination of the surgical specimen revealed proliferation of fibrocartilage and calcification. The patient's paraparesis ameliorated after the operation. CONCLUSION: For this case of myelopathy due to HPLL in the thoracic spine, urgent decompression gave excellent results. Clinical awareness of HPLL may aid correct diagnosis and prompt therapy.

Abstract: We describe two cases of spinal arachnoid cyst associated with syringomyelia and report the clinical results after surgical treatment using excision of the cyst without a shunt operation for the syringomyelia. Case 1 is a 73-year-old woman who presented with a spastic gait and numbness of her bilateral lower extremities. Magnetic resonance imaging (MRI) showed the presence of a spinal arachnoid cyst extending from T3 to T8 and syringomyelia from T8 to T10. The cyst had compressed the spinal cord anteriorly. We excised the cyst without applying a shunt tube for the syringomyelia. Case 2 is a 68-year-old woman who presented with gait disturbance and numbness of her left lower extremity. MRI indicated that the spinal cord had been compressed anteriorly by a spinal arachnoid cyst extending from T10 to T11. Syringomyelia existed just caudal to the cyst at T11. In our surgical treatment, we excised only the cyst. In both cases, neurologic examination after the operation showed amelioration of the condition. Postoperative MRI indicated that the spinal cord had moved to the center, its original position, and the syringomyelia had decreased in size. Conclusively, spinal arachnoid cyst associated with syringomyelia can be treated by simple excision of the cyst without shunting the syrinx if the decompression effect resulting from removal of the cyst is sufficient.

Abstract: STUDY DESIGN: Two case reports of intramedullary teratoma in the spinal cord of adults, and a review of the literature. OBJECTIVE: To investigate and describe unusual cases of spinal teratoma using MRI to define features that may be used to avoid misdiagnosis. SETTING: A department of orthopedic surgery in Japan. METHODS: One patient, a 37-year-old woman, was referred because of gait disturbance. She was evaluated by myelography, CT scan with myelography, and MRI. T12 through L1 laminoplasty was performed and the tumor was subtotally removed. The other patient, a 56-year-old man, was referred because of muscle weakness and sensory disturbance. MRI revealed multiple spinal tumors. C4 through C6 laminoplasty and T12 through L2 laminoplasty were performed, and the tumors in these regions were subtotally removed. RESULTS: In Case 1, the postoperative course was excellent, and histological examination of the resected specimen revealed a spinal teratoma consisting of ectodermal and mesodermal elements. In Case 2, the symptoms were resolved after surgery, and ectodermal, mesodermal and endodermal elements were revealed. CONCLUSIONS: Although intramedullary teratomas are very rare in adults, they need to be considered in differential diagnosis.

Abstract: Alexander disease is a rare, degenerative disorder of the central nervous system. It is characterized clinically by spasticity, seizures, dementia, loss of developmental milestones, and macrocephaly. Here we describe a 13-year-old boy with Alexander disease and severe scoliosis. The patient initially presented at 9 months of age, with profound mental retardation and a history of seizures. When he was 7 years old, a pediatrician had diagnosed Alexander disease (hypotonia, macrocephaly, and progressive low-density white matter predominantly in the frontal region on computed tomography examination). From the age of 10, thoracolumbar scoliosis had gradually become severe. Because treatment using a corrective brace would have produced major problems because of the patient's mental retardation, the scoliosis was successfully treated surgically, by careful posterior spinal fusion with instrumentation, and an autologous iliac crest bone graft. A 64 degrees curve was corrected to 18 degrees (72% correction). Scoliosis with Alexander disease is considered to be very rare because patients with the disease seldom survive long enough to develop spinal deformities.

Abstract: STUDY DESIGN: This study focused on the effects that abdominal belts have on the sagittal section of the abdominal and pelvic cavity during contraction of the trunk muscles. Fast magnetic resonance imaging was used during the Valsalva maneuver by 11 healthy men. OBJECTIVE: To evaluate the effect of an abdominal belt on the geometric changes in the sagittal section during Valsalva maneuvers. SUMMARY OF BACKGROUND DATA: Several hypotheses about the effect of an abdominal belt have considered intraabdominal pressure, which has a hydraulic effect on the diaphragm, providing stability to the spine. However, there is little information on changes in the sagittal section of the abdominal and pelvic cavity. METHODS: Eleven male volunteers without back problems were studied with fast magnetic resonance images. Sagittal section images of the abdominal and pelvic cavity were obtained under six conditions: without the belt at rest, at full inhalation, and at full inhalation with Valsalva, as well as with the belt at rest, at full inhalation, and at full inhalation with Valsalva. RESULTS: When the belt was worn, the sagittal section area of the abdominal and pelvic cavity did not change, but its shape did. Also, the anteroposterior diameter of the abdominal and pelvic cavity increased at its upper part and decreased at its middle part, elevating the liver and diaphragm. Additionally, the lever arm length of the intraabdominal pressure increased significantly. CONCLUSIONS: Fast magnetic resonance imaging quantified the effect of an abdominal belt on the abdominal geometric changes during the Valsalva maneuvers with the patient in a supine position.

Abstract: OBJECTIVES: To determine the types and causes of upper extremity injuries sustained while snowboarding. DESIGN: A prospective survey of snowboarders with upper extremity injuries, especially fractures and dislocations. PARTICIPANTS: Between 1995 and 2000, we analyzed and interviewed 6,837 injured snowboarders and 2,175 injured skiers, and a total of 2,742 snowboarders and 361 skiers with fractures or dislocations of the upper extremities were studied. RESULTS: The ratio of upper extremity injuries to all injury types was significantly higher in snowboarders (40%, p < 0.001). Shoulder dislocations accounted for 5.5% of all injuries in skiers but 71% of all dislocations. In comparison, 6.5% of snowboarders' injuries were shoulder dislocations, representing 50% of all dislocations. It was noted that dislocation of the elbow joint was a more characteristic injury of snowboarders (30%) than of skiers (3%). The most frequently fractured site in skiers was the clavicle (32% of all fractures), and in snowboarders, it was the wrist (62% of all fractures). The most frequently affected side of the snowboarders' upper extremity was the left, with the exception of wrist fractures. With the exception of wrist fractures, the edge side that caused the accident was the opposite of the side that was injured. Most snowboarders did not have initial instruction from professional instructors (93%) and did not use protective equipment (87%). CONCLUSIONS: The results of this study indicate that the upper extremity injuries are much more common in snowboarders than skiers. In particular, upper extremity fractures in snowboarders are three times more common than in skiers. Furthermore, in snowboarding, wrist fractures have a different underlying cause compared with other upper extremity injuries.

Abstract: The authors describe a simple, new method for removing broken pedicle screws. Under microscopic visualization a straight, narrow slot is etched in the broken surface of the pedicle screw by using a power drill with a 2-mm diamond burr. A minus screwdriver is then inserted into the slot, and the broken screw is rotated and removed. There is no need to enlarge the screw hole around the broken screw or to use any special devices. The authors succeeded in removing broken screws in two cases, and there were no complications. This method allows preservation of both the pedicle and the screw hole. Consequently, it is possible to insert new pedicle screws into the same hole without losing the strength and stability of pedicle screw fixation. The authors recommend this simple and new method for removal of broken pedicle screws.

Abstract: OBJECTIVE: To evaluate the effects of abdominal belts on lifting performance, muscle activation, intra-abdominal pressure and intra-muscular pressure of the erector spinae muscles. DESIGN: Simultaneous measurement of intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles was performed during the Valsalva maneuver and some isometric lift exertions. BACKGROUND: While several hypotheses have been suggested regarding the biomechanics of belts and performance has been found to increase when lifting with belts, very little is known about the modulating effects on trunk stiffness. At present, there is no reason to believe that spine tolerance to loads increases with belts. METHODS: An abdominal belt designed for weightlifting was used. Intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and myoelectric activities of trunk muscles (erector spinae, rectus abdominis and external oblique) were measured simultaneously during the Valsalva maneuver as well as three types of isometric lifting exertions (arm, leg and torso lift). A paired t-test was used to analyze for statistical differences between the two conditions (without-belt and with-belt) in intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and in the integrated EMG of the trunk muscles. RESULTS: Intra-muscular pressure of the erector spinae muscles increased significantly by wearing the abdominal belt during Valsalva maneuvers and during maximum isometric lifting exertions, while maximum isometric lifting capacity and peak intra-abdominal pressure were not affected. Integrated EMG of rectus abdominis increased significantly by wearing the abdominal belt during Valsalva maneuvers (after full inspiration) and during isometric leg lifting. CONCLUSIONS: Wearing abdominal belts raises intra-muscular pressure of the erector spinae muscles and appears to stiffen the trunk. Assuming that increased intra-muscular pressure of the erector spinae muscles stabilizes the lumbar spine, wearing abdominal belts may contribute to the stabilization during lifting exertions.

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Abstract: The aim of this study was to investigate the prevalence of subjective complaints among two groups of health care personnel. Using a mail questionnaire, 63 male orthopedists and 78 male general surgeons were asked to respond to questions on their subjective musculoskeletal complaints as well as their age, occupational career, and daily working time. In the final analysis, 54 orthopedists and 63 general surgeons who were aged < or = 59 years and had worked for at least 5 years in clinical practice were considered. The mean age was 43.3 (SD 7.6) years for the orthopedists and 41.8 (SD 9.5) years for the general surgeons. Their mean employment time was 18.1 (SD 8.9) years and 16.6 (SD 9.5) years, respectively. The average working time per day was 9.5 h. In general, the orthopedists had a higher prevalence of subjective complaints than the general surgeons. Problems in the shoulders and lower back were the most frequently reported complaints, followed by neck problems. There were significant differences (P < 0.05) between the two groups regarding stiffness in the shoulders, stiffness in the lower back, pain in the neck, and numbness in the fingers. When subjective complaints were compared between the junior (employment time: < 20 years) and senior (employment time: > or = 20 years) staff, the junior orthopedists had significantly higher prevalence rates for stiffness in the shoulders, pain in the neck, and stiffness in the lower back.(ABSTRACT TRUNCATED AT 250 WORDS)