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Constantin Schizas


cschizas@hotmail.com

Journal articles

2009
Evangelia M Tsapakis, Eleftherios Tsiridis, Alistair Hunter, Zakareya Gamie, Nikolaos Georgakarakos, Panos Thomas, Constantin Schizas, Robert M West (2009)  Modelling the effect of minor orthopaedic day surgery on patient mood at the early post-operative period: a prospective population-based cohort study.   Eur Psychiatry 24: 2. 112-118 Mar  
Abstract: OBJECTIVE: The effect of minor orthopaedic day surgery (MiODS) on patient's mood. METHODS: A prospective population-based cohort study of 148 consecutive patients with age above 18 and less than 65, an American Society of Anaesthesiology (ASA) score of 1, and the requirement of general anaesthesia (GA) were included. The Medical Outcomes Study - Short Form 36 (SF-36), Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) were used pre- and post-operatively. RESULTS: The mean physical component score of SF-36 before surgery was 45.3 (SD=+/-10.1) and 8 weeks following surgery was 44.9 (SD=+/-11.04) [n=148, p=0.51, 95% CI=(-1.03 to 1.52)]. For the measurement of the changes in mood using BDI, BAI and SF-36, latent construct modelling was employed to increase validity. The covariance between mood pre- and post-operatively (cov=69.44) corresponded to a correlation coefficient, r=0.88 indicating that patients suffering a greater number of mood symptoms before surgery continue to have a greater number of symptoms following surgery. When the latent mood constructs were permitted to have different means the model fitted well with chi(2) (df=1)=0.86 for which p=0.77, thus the null hypothesis that MiODS has no effect on patient mood was rejected. CONCLUSIONS: MiODS affects patient mood which deteriorates at 8 weeks post-operatively regardless of the pre-operative patient mood state. More importantly patients suffering a greater number of mood symptoms before MiODS continue to have a greater number of symptoms following surgery.
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C Schizas, J M Duff, E Tessitore, A Faundez (2009)  Non fusion techniques in spinal surgery   Rev Med Suisse 5: 230. 2574-2577 Dec  
Abstract: In order to prevent adjacent segment degeneration following spinal fusion new techniques are being used. Lumbar disc arthroplasty yields mid term results equivalent to those of spinal fusion. Cervical disc arthroplasty is indicated in the treatment of cervicobrachialgia with encouraging initial results. The ability of arthroplasty to prevent adjacent segment degeneration has yet to be proven. Although dynamic stabilization had not been proven effective in treating chronic low back pain, it might be useful following decompression of lumbar spinal stenosis in degenerative spondylolisthesis. Interspinal devices are useful in mild lumbar spinal stenosis but their efficacy in treating low back pain is yet to be proven. Confronted with a growing number of new technologies clinicians should remain critical while awaiting long term results.
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Constantin Schizas, Dimitrios Triantafyllopoulos, Victor Kosmopoulos, Kosmas Stafylas (2009)  Impact of iliac crest bone graft harvesting on fusion rates and postoperative pain during instrumented posterolateral lumbar fusion.   Int Orthop 33: 1. 187-189 Feb  
Abstract: This study aims to evaluate the influence of bone harvesting on postoperative pain and fusion rates. Group 1 patients received iliac crest bone graft (ICBG) either alone or augmented with local bone. Group 2 received only local bone. No statistical significance was found in radiological union or in the Oswestry Disability Index scores. Visual Analogue Scale scores showed less pain in group 2. Logistic regression showed no correlation between residual pain and occurrence of fusion. Harvesting ICBG did not appear to increase fusion rates and no relation was found between radiological non-union and pain.
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Victor Kosmopoulos, Tony S Keller, Constantin Schizas (2009)  Early stage disc degeneration does not have an appreciable affect on stiffness and load transfer following vertebroplasty and kyphoplasty.   Eur Spine J 18: 1. 59-68 Jan  
Abstract: Vertebroplasty and kyphoplasty have been reported to alter the mechanical behavior of the treated and adjacent-level segments, and have been suggested to increase the risk for adjacent-level fractures. The intervertebral disc (IVD) plays an important role in the mechanical behavior of vertebral motion segments. Comparisons between normal and degenerative IVD motion segments following cement augmentation have yet to be reported. A microstructural finite element model of a degenerative IVD motion segment was constructed from micro-CT images. Microdamage within the vertebral body trabecular structure was used to simulate a slightly (I = 83.5% of intact stiffness), moderately (II = 57.8% of intact stiffness), and severely (III = 16.0% of intact stiffness) damaged motion segment. Six variable geometry single-segment cement repair strategies (models A-F) were studied at each damage level (I-III). IVD and bone stresses, and motion segment stiffness, were compared with the intact and baseline damage models (untreated), as well as, previous findings using normal IVD models with the same repair strategies. Overall, small differences were observed in motion segment stiffness and average stresses between the degenerative and normal disc repair models. We did however observe a reduction in endplate bulge and a redistribution in the microstructural tissue level stresses across both endplates and in the treated segment following early stage IVD degeneration. The cement augmentation strategy placing bone cement along the periphery of the vertebra (model E) proved to be the most advantageous in treating the degenerative IVD models by showing larger reductions in the average bone stresses (vertebral and endplate) as compared to the normal IVD models. Furthermore, only this repair strategy, and the complete cement fill strategy (model F), were able to restore the slightly damaged (I) motion segment stiffness above pre-damaged (intact) levels. Early stage IVD degeneration does not have an appreciable effect in motion segment stiffness and average stresses in the treated and adjacent-level segments following vertebroplasty and kyphoplasty. Placing bone cement in the periphery of the damaged vertebra in a degenerative IVD motion segment, minimizes load transfer, and may reduce the likelihood of adjacent-level fractures.
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Constantin Schizas, Nicolas Tzinieris, Elefterios Tsiridis, Victor Kosmopoulos (2009)  Minimally invasive versus open transforaminal lumbar interbody fusion: evaluating initial experience.   Int Orthop 33: 6. 1683-1688 Dec  
Abstract: The aim of this study was to compare our experience with minimally invasive transforaminal lumbar interbody fusion (MITLIF) and open midline transforaminal lumbar interbody fusion (TLIF). A total of 36 patients suffering from isthmic spondylolisthesis or degenerative disc disease were operated with either a MITLIF (n = 18) or an open TLIF technique (n = 18) with an average follow-up of 22 and 24 months, respectively. Clinical outcome was assessed using the visual analogue scale (VAS) and the Oswestry disability index (ODI). There was no difference in length of surgery between the two groups. The MITLIF group resulted in a significant reduction of blood loss and had a shorter length of hospital stay. No difference was observed in postoperative pain, initial analgesia consumption, VAS or ODI between the groups. Three pseudarthroses were observed in the MITLIF group although this was not statistically significant. A steeper learning effect was observed for the MITLIF group.
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Aurelie Quintin, Constantin Schizas, Corinne Scaletta, Sandra Jaccoud, Stefan Gerber, Maria-Chiara Osterheld, Lucienne Juillerat, Lee Ann Applegate, Dominique P Pioletti (2009)  Isolation and in vitro chondrogenic potential of human foetal spine cells.   J Cell Mol Med 13: 8B. 2559-2569 Aug  
Abstract: Cell therapy for nucleus pulposus (NP) regeneration is an attractive treatment for early disc degeneration as shown by studies using autologous NP cells or stem cells. Another potential source of cells is foetal cells. We investigated the feasibility of isolating foetal cells from human foetal spine tissues and assessed their chondrogenic potential in alginate bead cultures. Histology and immunohistochemistry of foetal tissues showed that the structure and the matrix composition (aggrecan, type I and II collagen) of foetal intervertebral disc (IVD) were similar to adult IVD. Isolated foetal cells were cultured in monolayer in basic media supplemented with 10% Fetal Bovine Serum (FBS) and from each foetal tissue donation, a cell bank of foetal spine cells at passage 2 was established and was composed of around 2000 vials of 5 million cells. Gene expression and immunohistochemistry of foetal spine cells cultured in alginate beads during 28 days showed that cells were able to produce aggrecan and type II collagen and very low level of type I and type X collagen, indicating chondrogenic differentiation. However variability in matrix synthesis was observed between donors. In conclusion, foetal cells could be isolated from human foetal spine tissues and since these cells showed chondrogenic potential, they could be a potential cell source for IVD regeneration.
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Felix Neumayer, Victor Kosmopoulos, Constantin Schizas (2009)  Management of a post-operative multi-resistant infectious spondylitis associated with a kyphotic deformity.   Acta Orthop Belg 75: 4. 566-570 Aug  
Abstract: Anterior spinal infection (prevertebral abscess and/or discitis) after posterior instrumentation for vertebral fractures is a challenging complication, since a new implant may become necessary anteriorly, in a septic environment. Generally accepted management guidelines are yet to be established. The authors present a case of posterior instrumentation for fractures of T12 and L1, complicated after 9 months with an anterior infection (prevertebral abscess and discitis) with extended-spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli). This case is unique in that the multi-resistant organism was isolated only after the second stage of infection treatment, which consisted of anterior débridement and anterior implantation of titanium cages and rods. In this particular case, infection was controlled despite implantation of multiple cages, screws and rods, and fusion was achieved, by means of intravenous antibiotic treatment for 12 months. At the latest follow-up, 24 months post surgery, there was no evidence of infection. This problem case may be helpful for surgeons confronted with spinal deformities secondary to infections with multi-resistant organisms.
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Constantin Schizas, Noël Foko'o, Maurice Matter, Sebastien Romy, Everard Munting (2009)  Lymphocoele: a rare and little known complication of anterior lumbar surgery.   Eur Spine J 18 Suppl 2: 228-231 Jul  
Abstract: Lymphocoele is a rare and little known complication with only a handful of reports available. We report two cases of lymphocoele after anterior lumbar surgery that have occurred in two different centres and discuss diagnosis and management options. The first case is that of a 53-year-old male patient undergoing two level anterior lumbar interbody fusion (ALIF) for disabling back pain due to disc degeneration in the context of an old spondylodiscitis. He developed a large fluid mass postoperatively. Fluid levels of creatinin were low and intravenous urography ruled out a urinoma suggesting the diagnosis of a lymphocoele. Following two unsuccessful drainage attempts he underwent a laparoscopic marsupialization. The second case was that of a 32-year-old female patient developing a large fluid mass following a L5 corpectomy for a burst fracture. She was treated successfully with insertion of a vacuum drain during 7 days. Lymphocoele is a rare complication but should be suspected if fluid collects postoperatively following anterior lumbar spine procedures. Chemical analysis of the fluid can help in diagnosis. Modern treatment consists of laparoscopic marsupialization. Lymph vessel anatomy should be borne in mind while exposing the anterior lumbar spine.
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2008
Victor Kosmopoulos, Constantin Schizas, Tony S Keller (2008)  Modeling the onset and propagation of trabecular bone microdamage during low-cycle fatigue.   J Biomech 41: 3. 515-522  
Abstract: Relatively small amounts of microdamage have been suggested to have a major effect on the mechanical properties of bone. A significant reduction in mechanical properties (e.g. modulus) can occur even before the appearance of microcracks. This study uses a novel non-linear microdamaging finite-element (FE) algorithm to simulate the low-cycle fatigue behavior of high-density trabecular bone. We aimed to investigate if diffuse microdamage accumulation and concomitant modulus reduction, without the need for complete trabecular strut fracture, may be an underlining mechanism for low-cycle fatigue failure (defined as a 30% reduction in apparent modulus). A microCT constructed FE model was subjected to a single cycle monotonic compression test, and constant and variable amplitude loading scenarios to study the initiation and accumulation of low-cycle fatigue microdamage. Microcrack initiation was simulated using four damage criteria: 30%, 40%, 50% and 60% reduction in bone element modulus (el-MR). Evaluation of structural (apparent) damage using the four different tissue level damage criteria resulted in specimen fatigue failure at 72, 316, 969 and 1518 cycles for the 30%, 40%, 50% and 60% el-MR models, respectively. Simulations based on the 50% el-MR model were consistent with previously published experimental findings. A strong, significant non-linear, power law relationship was found between cycles to failure (N) and effective strain (Deltasigma/E(0)): N=1.394x10(-25)(Deltasigma/E(0))(-12.17), r(2)=0.97, p<0.0001. The results suggest that microdamage and microcrack propagation, without the need for complete trabecular strut fracture, are mechanisms for high-density trabecular bone failure. Furthermore, the model is consistent with previous numerical fatigue simulations indicating that microdamage to a small number of trabeculae results in relatively large specimen modulus reductions and rapid failure.
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Constantin Schizas, Dimitrios Triantafyllopoulos, Victor Kosmopoulos, Nikos Tzinieris, Kosmas Stafylas (2008)  Posterolateral lumbar spine fusion using a novel demineralized bone matrix: a controlled case pilot study.   Arch Orthop Trauma Surg 128: 6. 621-625 Jun  
Abstract: INTRODUCTION: Intertransverse posterolateral fusion along with instrumentation is a common technique used for spinal fusion. Iliac crest bone graft (ICBG) offers good fusion success rates with a low risk for disease transmission but is, however, linked with certain morbidity. In an effort to eliminate or reduce the amount of iliac graft needed, bone substitutes including demineralized bone matrix (DBM) have been developed. This study evaluates a novel DBM (Accell Connexus used in one or two-level instrumented posterolateral lumbar fusion. MATERIALS AND METHODS: A total of 59 consecutive patients were studied as two groups. Group 1 consisted of 33 patients having Accell Connexus used to augment either ICBG or local decompression material. Group 2 consisted of 26 consecutive patients, operated prior to the introduction of this novel DBM, having either ICBG alone or local decompression material. Fusion was assessed by two independent observers, blinded to graft material, using standardized criteria found in the literature. All adverse events were recorded prospectively. RESULTS: The results show no statistically significant differences between the two groups in fusion rates, complications, surgery duration, ODI, or pain on VAS. Logistical regression showed no relation between fusion and age, smoking status or comorbidities. Furthermore, no adverse events related to the use of the novel DBM were observed. CONCLUSION: The results from this study demonstrate that the novel DBM presented performs equally as well as that of autologous bone, be it either ICBG or a local decompression material, and can therefore be used as a graft extender.
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Victor Kosmopoulos, John McManus, Constantin Schizas (2008)  Consequences of patient position in the radiographic measurement of artificial disc replacement angles.   Eur Spine J 17: 1. 30-35 Jan  
Abstract: Accurate clinical measurement of spinal range of motion (ROM) is essential in the evaluation of artificial disc performance. The effect of patient placement with respect to the X-ray beam source is yet to be reported and may be an influencing factor in radiographic artificial disc angle measurements. This study aims to evaluate how radiographic patient placement influences artificial disc angle measurements. An anatomically accurate synthetic L4-L5 motion segment was instrumented with an artificial disc and two pins. The instrumented motion segment was mounted onto a frame allowing for independent rotation and elevation while holding the artificial disc angle and anatomical position between L4 and L5 fixed. Analyses included descriptive statistics, evaluation of uncertainty, intra- and inter-observer, and a 2-way analysis of variance (ANOVA). The mean angle measurement range at the various positions was 1.26 degrees for the pin, and 2.74 degrees for the artificial disc endplates. The centered patient position had the highest inter- and intra-observer reliability. ANOVA results showed elevation effects to be statistically significant (P = 0.021), and rotational effects to be extremely statistically significant (P < 0.0001) for the pin angles. In terms of the mean artificial disc angle, however, the ANOVA showed a highly statistically significant interaction term (P = 0.002). A significant difference was found in the angle measurements of a fixed artificial disc prosthesis based on a sample of patient radiographic placement positions. Since it is important to assess the success of an artificial disc replacement by evaluating the relatively small ROM present, it is crucial to aim at minimizing the error by placing the patient parallel to the plate with the beam centered not at the mid lumbar spine, but at the level of the arthroplasty, for both flexion and extension views.
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Robert J Macfarlane, Boon Han Ng, Zakareya Gamie, Mohamed A El Masry, Stylianos Velonis, Constantin Schizas, Eleftherios Tsiridis (2008)  Pharmacological treatment of heterotopic ossification following hip and acetabular surgery.   Expert Opin Pharmacother 9: 5. 767-786 Apr  
Abstract: Heterotopic ossification is a common complication following total hip arthroplasty and surgery following acetabular trauma. It is associated with pain and a decreased range of movement. Prophylaxis is achieved by either non-steroidal anti-inflammatory drug treatment or localised irradiation therapy. The objective of this study was to evaluate the evidence for pharmacological agents used for the prophylaxis of heterotopic ossification following hip and acetabular surgery. The study used a comprehensive literature search to identify all major clinical studies investigating the pharmacological agents used in the prophylaxis of heterotopic ossification following hip and acetabular surgery. It was concluded that indometacin remains the 'gold standard' for heterotopic ossification prophylaxis following total hip arthroplasty and is the only drug proven to be effective against heterotopic ossification following acetabular surgery. Following total hip arthroplasty, other non-steroidal anti-inflammatory drugs, including naproxen and diclofenac, are equally as effective as indometacin and can be considered as alternative first-line treatments. Celecoxib is also of equal efficacy to indometacin and is associated with significantly fewer gastrointestinal side effects. However, serious concerns were raised over the safety of selective cyclooxygenase-2 inhibitors for the cardiovascular system and these should be used cautiously.
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J Saksena, V Kosmopoulos, C Schizas (2008)  An intramedullary alignment guide lodging within the femoral canal during total knee arthroplasty: a case report.   J Orthop Surg (Hong Kong) 16: 1. 114-116 Apr  
Abstract: The usual complications of total knee arthroplasty include thrombo-embolism, infection, and loosening. We report an unusual and potentially serious complication of an intramedullary guide lodging within the femoral canal during the procedure. Considering the risk of fracture and additional exposure, the guide was not removed and was cut in situ. The rest of the operation was completed successfully and the patient made an uneventfully recovery.
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C Schizas, F Neumayer, V Kosmopoulos (2008)  Incidence and management of pulmonary embolism following spinal surgery occurring while under chemical thromboprophylaxis.   Eur Spine J 17: 7. 970-974 Jul  
Abstract: Patients undergoing spinal surgery are at risk of developing thromboembolic complications even though lower incidences have been reported as compared to joint arthroplasty surgery. Deep vein thrombosis (DVT) has been studied extensively in the context of spinal surgery but symptomatic pulmonary embolism (PE) has engaged less attention. We prospectively followed a consecutive cohort of 270 patients undergoing spinal surgery at a single institution. From these patients, only 26 were simple discectomies, while the largest proportion (226) was fusions. All patients received both low molecular weight heparin (LMWH) initiated after surgery and compressive stockings. PE was diagnosed with spiral chest CT. Six patients developed symptomatic PE, five during their hospital stay. In three of the six patients the embolic event occurred during the first 3 postoperative days. They were managed by the temporary insertion of an inferior vena cava (IVC) filter thus allowing for a delay in full-dose anticoagulation until removal of the filter. None of the PE patients suffered any bleeding complication as a result of the introduction of full anticoagulation. Two patients suffered postoperative haematomas, without development of neurological symptoms or signs, requiring emergency evacuation. The overall incidence of PE was 2.2% rising to 2.5% after exclusion of microdiscectomy cases. The incidence of PE was highest in anterior or combined thoracolumbar/lumbar procedures (4.2%). There is a large variation in the reported incidence of PE in the spinal literature. Results from the only study found in the literature specifically monitoring PE suggest an incidence of PE as high as 2.5%. Our study shows a similar incidence despite the use of LMWH. In the absence of randomized controlled trials (RCT) it is uncertain if this type of prophylaxis lowers the incidence of PE. However, other studies show that the morbidity of LMWH is very low. Since PE can be a life-threatening complication, LMWH may be a worthwhile option to consider for prophylaxis. RCTs are necessary in assessing the efficacy of DVT and PE prophylaxis in spinal patients.
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Tobias Lindner, Andrew J Cockbain, Mohamed A El Masry, Paul Katonis, Evgenios Tsiridis, Constantin Schizas, Eleftherios Tsiridis (2008)  The effect of anticoagulant pharmacotherapy on fracture healing.   Expert Opin Pharmacother 9: 7. 1169-1187 May  
Abstract: BACKGROUND: There is in vitro and in vivo evidence that anticoagulants impair normal bone metabolism, and it is widely believed that this may impair fracture healing. However, there are only a few heterogeneous in vivo animal studies confirming this and the mechanisms are not fully understood. OBJECTIVE: To review the literature concerning the effects of anticoagulants on fracture healing, and to present current understanding of the mechanisms involved by reviewing in vivo studies of bone biology and in vitro studies of bone cells. METHODS: A systematic search of Medline and other databases was combined with manual searching of bibliographies of key papers to identify relevant studies in the English and German languages. CONCLUSION: There is strong evidence that warfarin, heparin and aspirin retard fracture healing. The preferential use of low molecular weight heparins is advocated to minimise this. Fondaparinux has not shown any impairment in vitro. Further studies of fondaparinux, the timing of anticoagulation therapy and the mechanisms of action of these agents are of paramount importance.
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Victor Kosmopoulos, Kosmas Stafylas, John McManus, Constantin Schizas (2008)  Radiographic total disc replacement angle measurement accuracy using the Oxford Cobbometer: precision and bias.   Eur Spine J 17: 8. 1066-1072 Aug  
Abstract: Total disc replacement (TDR) clinical success has been reported to be related to the residual motion of the operated level. Thus, accurate measurement of TDR range of motion (ROM) is of utmost importance. One commonly used tool in measuring ROM is the Oxford Cobbometer. Little is known however on its accuracy (precision and bias) in measuring TDR angles. The aim of this study was to assess the ability of the Cobbometer to accurately measure radiographic TDR angles. An anatomically accurate synthetic L4-L5 motion segment was instrumented with a CHARITE artificial disc. The TDR angle and anatomical position between L4 and L5 was fixed to prohibit motion while the motion segment was radiographically imaged in various degrees of rotation and elevation, representing a sample of possible patient placement positions. An experienced observer made ten readings of the TDR angle using the Cobbometer at each different position. The Cobbometer readings were analyzed to determine measurement accuracy at each position. Furthermore, analysis of variance was used to study rotation and elevation of the motion segment as treatment factors. Cobbometer TDR angle measurements were most accurate (highest precision and lowest bias) at the centered position (95.5%), which placed the TDR directly inline with the x-ray beam source without any rotation. In contrast, the lowest accuracy (75.2%) was observed in the most rotated and off-centered view. A difference as high as 4 degrees between readings at any individual position, and as high as 6 degrees between all the positions was observed. Furthermore, the Cobbometer was unable to detect the expected trend in TDR angle projection with changing position. Although the Cobbometer has been reported to be reliable in different clinical applications, it lacks the needed accuracy to measure TDR angles and ROM. More accurate ROM measurement methods need to be developed to help surgeons and researchers assess radiological success of TDRs.
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2007
Constantin Schizas, Nicolas Theumann, Victor Kosmopoulos (2007)  Inserting pedicle screws in the upper thoracic spine without the use of fluoroscopy or image guidance. Is it safe?   Eur Spine J 16: 5. 625-629 May  
Abstract: Several studies have looked at accuracy of thoracic pedicle screw placement using fluoroscopy, image guidance, and anatomical landmarks. To our knowledge the upper thoracic spine (T1-T6) has not been specifically studied in the context of screw insertion and placement accuracy without the use of either image guidance or fluoroscopy. Our objective was to study the accuracy of upper thoracic screw placement without the use of fluoroscopy or image guidance, and report on implant related complications. A single surgeon inserted 60 screws in 13 consecutive non-scoliotic spine patients. These were the first 60 screws placed in the high thoracic spine in our institution. The most common diagnosis in our patient population was trauma. All screws were inserted using a modified Roy-Camille technique. Post-operative axial computed tomography (CT) images were obtained for each patient and analyzed by an independent senior radiologist for placement accuracy. Implant related complications were prospectively noted. No pedicle screw misplacement was found in 61.5% of the patients. In the remaining 38.5% of patients some misplacements were noted. Fifty-three screws out of the total 60 implanted were placed correctly within all the pedicle margins. The overall pedicle screw placement accuracy was 88.3% using our modified Roy-Camille technique. Five medial and two lateral violations were noted in the seven misplaced screws. One of the seven misplaced screws was considered to be questionable in terms of pedicle perforation. No implant related complications were noted. We found that inserting pedicle screws in the upper thoracic spine based solely on anatomical landmarks was safe with an accuracy comparable to that of published studies using image-guided navigation at the thoracic level.
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Victor Kosmopoulos, Constantin Schizas (2007)  Pedicle screw placement accuracy: a meta-analysis.   Spine (Phila Pa 1976) 32: 3. E111-E120 Feb  
Abstract: STUDY DESIGN: A meta-analysis of the published literature was conducted specifically looking at accuracy and the postoperative methods used for the assessment of pedicle screw placement in the human spine. OBJECTIVES: This study specifically aimed to identify postoperative methods used for pedicle screw placement assessment, including the most common method, and to report cumulative pedicle screw placement study statistics from synthesis of the published literature. SUMMARY OF BACKGROUND DATA: Safety concerns have driven specific interests in the accuracy and precision of pedicle screw placement. A large variation in reported accuracy may exist partly due to the lack of a standardized evaluation method and/or the lack of consensus to what, or in which range, is pedicle screw placement accuracy considered satisfactory. METHODS: A MEDLINE search was executed covering the span from 1966 until 2006, and references from identified papers were reviewed. An extensive database was constructed for synthesis of the identified studies. Subgroups and descriptive statistics were determined based on the type of population, in vivo or cadaveric, and separated based on whether the assistance of navigation was employed. RESULTS: In total, we report on 130 studies resulting in 37,337 total pedicle screws implanted, of which 34,107 (91.3%) were identified as accurately placed for the combined in vivo and cadaveric populations. The most common assessment method identified pedicle screw violations simply as either present or absent. Overall, the median placement accuracy for the in vivo assisted navigation subgroup (95.2%) was higher than that of the subgroup without the use of navigation (90.3%). CONCLUSIONS: Navigation does indeed provide a higher accuracy in the placement of pedicle screws for most of the subgroups presented. However, an exception is found at the thoracic levels for both the in vivo and cadaveric populations, where no advantage in the use of navigation was found.
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Constantin Schizas, Jacky Michel, Victor Kosmopoulos, Nicolas Theumann (2007)  Computer tomography assessment of pedicle screw insertion in percutaneous posterior transpedicular stabilization.   Eur Spine J 16: 5. 613-617 May  
Abstract: Percutaneous insertion of cannulated pedicle screws has been recently developed as a minimally invasive alternative to the open technique during instrumented fusion procedures. Given the reported rate of screw misplacement using open techniques (up to 40%), we considered it important to analyze possible side effects of this new technique. Placement of 60 pedicle screws in 15 consecutive patients undergoing lumbar or lumbosacral fusion, mainly for spondylolisthesis, were analyzed. Axial, coronal, and sagittal reformatted computer tomography images were examined by three observers. Individual and consensus interpretation was obtained for each screw position. Along with frank penetration, we also looked at cortical encroachment of the pedicular wall by the screw. Thirteen percent of the patients (2/15) had severe frank penetration from the screws, while 80% of them (12/15) had some perforation. On axial images the incidence of severe frank pedicle penetration was 3.3% while the overall rate of screw perforation was 23%. In coronal images the overall screw perforation rate rose to 30% while the rate of severe frank pedicle penetration remained unchanged. One patient (6.6%) suffered S1 root symptoms due to a frankly medially misplaced screw, requiring re-operation. This study has shown that percutaneous insertion of cannulated pedicle screws in the lumbar spine is an acceptable procedure. The overall rate of perforation in axial images is below the higher rates reported in the literature but does remain important. Frank penetration of the pedicle was nevertheless low. It remains a demanding technique and has to be performed with extreme care to detail.
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Victor Kosmopoulos, Nicolas Theumann, Stefano Binaghi, Constantin Schizas (2007)  Observer reliability in evaluating pedicle screw placement using computed tomography.   Int Orthop 31: 4. 531-536 Aug  
Abstract: Pedicle screw insertion in spinal surgery is a demanding technique with potential risks to neurological structures, for example, within the spinal canal. Assessing screw placement in clinical practice has been performed using plain radiographs and/or mainly axial computed tomography (CT) images. Screw placement using CT image reconstructions in multiple planes has been described, but its reliability has yet to be studied. This study aimed at addressing the clinical issue of interobserver and intraobserver reliability in the use of axial and coronal CT images for the assessment of pedicle screw placement. Fifty nine pedicle screws were studied by two experienced radiologists on two separate occasions. Screw placement was classified as "in", "out" or "questionable". On average, 88% and 92% of the screws were classified as "in" by the first and second radiologist, respectively. Intraobserver agreement strength was almost perfect for both observers using either axial or coronal images. Interobserver agreement strength was almost perfect (axial) and substantial (coronal) in the first reading and substantial (axial, coronal) in the second reading. Assessing screw placement in more than one CT imaging plane is not only useful but reliable. Routine use may enhance reporting quality of screw placement by surgeons and radiologists.
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B M Jolles, R Garofalo, L Gillain, C Schizas (2007)  A new clinical test in diagnosing quadriceps tendon rupture.   Ann R Coll Surg Engl 89: 3. 259-261 Apr  
Abstract: INTRODUCTION: Extensor mechanism ruptures might be easily overlooked and misdiagnosed, and delayed diagnosis of quadriceps tendon rupture is frequent. However, the literature recommends early surgical repair within 72 h. PATIENTS AND METHODS: This paper describes a new simple clinical diagnostic test that directly evaluates the integrity of the distal 5 cm of the quadriceps tendon itself. It consists of inserting a needle in the tendon, proximal to the suspected rupture and mobilising the knee joint. RESULTS: The suspected ruptured quadriceps tendons with a positive 'needle' diagnostic test were confirmed intra-operatively. CONCLUSIONS: This minimally invasive and easily available technique should be considered in the diagnostic work-up and treatment planning of patients with suspected tears of the quadriceps tendon.
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Constantin Schizas, Victor Kosmopoulos (2007)  Percutaneous surgical treatment of chance fractures using cannulated pedicle screws. Report of two cases.   J Neurosurg Spine 7: 1. 71-74 Jul  
Abstract: Chance fractures are relatively rare injuries and can be treated either conservatively, with a cast, or surgically, especially when posterior ligament injury is present. This paper presents two cases of lumbar Chance fractures treated using recently developed percutaneous cannulated pedicle screws. The first patient suffered associated abdominal injuries that required surgery, while the second had associated stable spinal fractures. Intraoperative blood loss was minimal. Both patients progressed to osseous union without implant failure. Following minimally invasive implant removal 9 months after injury, both patients remained asymptomatic without any evidence of instability on flexion and extension images obtained during their latest follow-up. This technique may be useful in selected cases in which bone grafting is not necessary; it allows early mobilization and stable fixation while minimizing morbidity.
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Aurelie Quintin, Nathalie Hirt-Burri, Corinne Scaletta, Constantin Schizas, Dominique P Pioletti, Lee Ann Applegate (2007)  Consistency and safety of cell banks for research and clinical use: preliminary analysis of fetal skin banks.   Cell Transplant 16: 7. 675-684  
Abstract: Current restrictions for human cell-based therapies have been related to technological limitations with regards to cellular proliferation capacity, maintenance of differentiated phenotype for primary human cell culture, and transmission of communicable diseases. We have seen that cultured primary fetal cells from one organ donation could possibly meet the exigent and stringent technical aspects for development of therapeutic products. We could develop a master cell bank (MCB) of 50 homogenous ampoules of 4-5 million cells each from one fetal organ donation (skin) in short periods of time compared to other primary cell types. Safety tests were performed at all stages of the cell banking. MCB ampoules could create a working cell bank to be used for clinical or research use. Monolayer culture of fetal skin cells had a life span of 12-17 passages, and independent cultures obtained from the same organ donation were consistent for protein concentration (with 1.4-fold maximal difference between cultures) as well as gene expression of MMP-14, MMP-3, TIMP-3, and VEGF (1.4-, 1.9-, 2.1-, and 1.4-fold maximal difference between cultures, respectively). Cell cultures derived from four independent fetal skin donations were consistent for cell growth, protein concentration, and gene expression of MDK, PTN, TGF-beta1, and OPG. As it is the intention that banked primary fetal cells can profit from the potential treatment of hundreds of thousands of patients with only one organ donation, it is imperative to show consistency, tracability, and safety of the process, including donor tissue selection, cell banking, cell testing, and growth of cells in upscaling for the preparation of cell transplantation.
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2006
Constantin Schizas, Liliana Belgrand, Michael Norberg (2006)  Surgical treatment of radicular pain using minimally invasive techniques   Rev Med Suisse 2: 92. 2931-2933 Dec  
Abstract: Radicular pain can be caused by disc herniation, lateral stenosis, isthmic spondylolisthesis with foraminal stenosis, or foraminal encroachment due to asymmetrical disc degeneration or scoliosis. Surgery is indicated following failure of conservative treatment. Minimally invasive discectomy is indicated for subjects presenting with radicular pain with or without neurological deficit and appropriate sized herniation in MRI. It offers equivalent efficacy but quicker recovery than microdiscectomy. Minimally invasive fusion is indicated for radicular pain due to foraminal compression in isthmic spondylolisthesis, asymmetric disc degeneration or scoliosis. It allows decrease in blood loss and postoperative pain. A less invasive technique should nevertheless not replace properly conducted conservative treatment.
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E Mouhsine, M Wettstein, C Schizas, O Borens, C - H Blanc, P - F Leyvraz, N Theumann, R Garofalo (2006)  Modified triangular posterior osteosynthesis of unstable sacrum fracture.   Eur Spine J 15: 6. 857-863 Jun  
Abstract: We report preliminary results for unstable sacral fractures treated with a modified posterior triangular osteosynthesis. Seven patients were admitted to our trauma center with an unstable sacral fracture. The average age was 31 years (22-41). There were four vertical shear lesions of the pelvis and three transverse fracture of the upper sacrum. The vertical shear injuries were initially treated with an anterior external fixator inserted at the time of admission. Definitive surgery was performed at a mean time of 9 days after trauma. The operation consisted in a posterior fixation combining a vertebropelvic distraction osteosynthesis with pedicle screws and a rod system, whereby the transverse fixation was obtained using a 6 mm rod as a cross-link between the two main rods. Late displacement of the posterior pelvis or fracture was measured on X-ray films according to the criteria of Henderson. The patients were followed-up for a minimum time of 12 months. Four patients who presented with a pre-operative perineal neurological impairment made a complete recovery. No iatrogenic nerve injury was reported. One case of deep infection was managed successfully with surgical debridement and local antibiotics. All patients complained of symptoms related to the prominence of the iliac screws. The metalwork was removed in all cases after healing of the fracture, at a mean time of 4.3 months after surgery. No loss of reduction of fracture was seen at final radiological follow-up. The preliminary results are promising. The fixation is sufficiently stable to allow an immediate progressive weight-bearing, and safe nursing care in polytrauma cases. The only problem seems to be related to prominent heads of the distal screws.
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Ali Djahangiri, Raffaele Garofalo, François Chevalley, Pierre-François Leyvraz, Michael Wettstein, Olivier Borens, Constantin Schizas, Elyazid Mouhsine (2006)  Closed and open grade I and II tibial shaft fractures treated by reamed intramedullary nailing.   Med Princ Pract 15: 4. 293-298  
Abstract: OBJECTIVE: To evaluate the results of closed and open grade I and II tibial shaft fractures treated by reamed nail and unreamed nailing. SUBJECTS AND METHODS: Between 1997 and 2000, 119 patients with tibial shaft fractures were treated with reamed tibial nails. Postoperatively 96 patients (70 closed and 26 grade I and II open fractures) were followed clinically and radiologically for up to 18 months. The nail was inserted either by patellar tendon splitting or by nonsplitting technique. The nail was inserted after overreaming by 1.5 mm. Postoperatively, patients with isolated tibial fracture were mobilized by permitting partial weight bearing on the injured leg for 6 weeks. Patients with associated ankle fractures were allowed to walk with a Sarmiento cast. RESULTS: Postoperatively, 6 (6.3%) patients developed a compartment syndrome after surgery. In 48 (50%) cases, dynamization of the nail was carried out after a mean period of 12 weeks for delayed union. Overall, a 90.6% union was obtained at a mean of 24 weeks without difference between closed or open fractures. Two (2.1%) patients with an open grade II fracture developed a deep infection requiring treatment. A 9.4% rate of malunion was observed. Eight (8.3%) patients developed screw failure without clinical consequences. At the last follow-up, 52% of patients with patellar tendon splitting had anterior knee pain, compared to those (14%) who did not have tendon splitting. CONCLUSION: Reamed intramedullary nail is a suitable implant in treating closed as well as grade I and II open tibial shaft fractures.
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Constantin Schizas, Nicolas Theumann (2006)  An unusual natural history of a L5-S1 spondylolisthesis presenting with a sacral insufficiency fracture.   Eur Spine J 15: 4. 506-509 Apr  
Abstract: Sacral insufficiency fractures have been described in association with conditions leading to osteoporosis. No association with spondylolisthesis has been described to date. A 60-year-old patient with known lumbosacral isthmic spondylolisthesis presented with exacerbation of symptoms initially thought to be linked to her known spinal pathology. Plain radiography, computer tomography, MRI and bone scan confirmed the presence of a recent sacral insufficiency fracture with anterior angulation. Conservative treatment resulted in improvement of symptoms after 6 months. Care should be taken when considering older patients for more aggressive treatment if they present with exacerbation of back pain and sciatica in the presence of a pre-existing spondylolisthesis. A suspicion of insufficiency fracture should be raised if risk factors exist and further investigations ordered in particular if plain radiography is normal. Lumbosacral fusion might be inappropriate in this setting.
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Elyazid Mouhsine, Raffaele Garofalo, François Chevalley, Biagio Moretti, Nicolas Theumann, Olivier Borens, Nicola Maffulli, Constantin Schizas, Michael Wettstein (2006)  Posttraumatic coccygeal instability.   Spine J 6: 5. 544-549 Sep/Oct  
Abstract: PURPOSE: To report the middle term results of partial coccygectomy in a consecutive series of 15 patients with chronic coccygodynia. METHODS: Fifteen patients with chronic coccygodynia were referred to our outpatient clinics. The patients were investigated with dynamic lateral radiography and magnetic resonance imaging (MRI). We diagnosed a posttraumatic coccygodynia with instability of the coccygeal segment and performed a partial coccygectomy after failure of the conservative treatment. RESULTS: All patients underwent subjective and objective assessment after a mean time of 2.8 years from surgery. There were 11 excellent, 3 good, and 1 fair results. The mean time of improvement was 15 weeks, and no further improvement was observed after 6 months. CONCLUSION: Partial coccygectomy is a good therapeutic option for posttraumatic coccygodynia. Dynamic radiography is a useful tool to differentiate posttraumatic from idiopathic coccygodynia. MRI may be useful for further evaluation of the patients after inconclusive dynamic radiography.
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P de Goumoëns, C Schizas, A K L So (2006)  Low back pain in 2006: back to the root   Rev Med Suisse 2: 65. 1268-70, 1272-4 May  
Abstract: Low back pain is a major burden for health care. According to the International Classification of Function, it is a disability of complex origin. Risk factors for chronification are of psychosocial and not physical nature. Primary targets of treatment should be physical fitness and the self-management of problem by the patient. Awareness of the psychosocial factors (yellow, blue and black flags) which can disturb occupational reintegration should be developed. Rehabilitation is based on measures to modify patient's beliefs and fitness. The prescribed treatment should aim to relieve pain, correct disability, prevent relapses, inform and educate the patient. Every low back pain sufferer which does not improve in 1 month should be sent to a team skilled in handling this kind of problem.
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2005
Eleftherios Tsiridis, Amir Ali Narvani, Constantin Schizas (2005)  Through-the-nail technique.   Acta Orthop Belg 71: 2. 223-226 Apr  
Abstract: Ipsilateral fractures of the neck of the femur and the femoral shaft are uncommon injuries and they present considerable challenge as the concurrent survival of the femoral head and union of the femoral shaft fracture is of paramount importance. We present a young male patient who sustained a Garden IV fracture of the neck of his right femur following a road traffic accident, with the fracture being adjacent to an ipsilateral intramedullary nail inserted 10 years previously for a midshaft femoral fracture; the nail was broken, with its proximal fragment lying behind the greater trochanter. The patient was operated on within 6 hours from the injury. An attempt was made to remove the nail but this was abandoned as warring iatrogenic bone loss was encountered, due to the proximity of the fracture to the nail entry point. Instead, three cancellous lag-screws were inserted to fix the fracture in a triangular fashion. Two screws placed posteriorly behind the nail, and one anterior screw through the nail.
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N Theumann, A Uske, E Mouhsine, C Schizas, F Chevalley, P Schnyder, S Binaghi (2005)  Percutaneous vertebroplasty   Rev Med Suisse 1: 27. 1780-1784 Jul  
Abstract: Although vertebroplasty was initially a treatment of vertebral haemangioma or metastases, this procedure is now frequent option to the treatment of osteoporotic vertebral fractures. In this review article, we will discuss the indication, the techniques and the follow-up of the vertebroplasty. This is a risky procedure, which should be performed by experimented physicians working with high-resolution fluoroscopic equipments, by biplane fluoroscopy, to reduce the risk and irradiation to the patient. According to the available follow-up studies, there is clear evidence of a strong improvement of quality of life after vertebroplasty by rapid decreasing of back pain at least during the first six months. Other new studies will analyze the long-term follow-up after vertebroplasty.
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Constantin Schizas, Elefterios Tsiridis, Joyti Saksena (2005)  Microendoscopic discectomy compared with standard microsurgical discectomy for treatment of uncontained or large contained disc herniations.   Neurosurgery 57: 4 Suppl. 357-60; discussion 357-60 Oct  
Abstract: OBJECTIVE: Minimally invasive spinal techniques have been developed for years in an attempt to minimize trauma. However, most endoscopic techniques have been unable to address uncontained or large contained disc herniations. The aim of this prospective study was to compare the results of microendoscopic discectomy (MED) and microsurgical discectomy in the treatment of patients with uncontained or large contained disc herniations. METHODS: An independent observer reviewed the treatment of 28 patients. The study group included 14 consecutive patients who underwent MED and 14 consecutive patients who underwent microsurgical discectomy for radicular pain secondary to uncontained or large contained disc herniations during the same period. Patients were followed up for an average of 12 months. They were assessed by use of Oswestry disability questionnaire and low back pain outcome score. RESULTS: The average outcome score improvement was of clinical significance in both patient groups. No difference in the scores was found between the two groups. Patients in the MED group required less postoperative analgesia during their stay. One patient in the MED group had a dural tear. CONCLUSION: MED is at least as effective as microsurgical discectomy for treatment of uncontained or large contained disc herniations, although the advantages over the open technique are short lived and did not reach significance. Nonetheless, for the surgeon accustomed to endoscopic techniques, MED seems to be a safe procedure.
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C Schizas, E Mouhsine, F Chevalley, Ns Theumann, J Duff (2005)  Surgical indications in spinal trauma   Rev Med Suisse 1: 46. 2978-2981 Dec  
Abstract: Surgical indications in spinal trauma remain a controversial topic. In general, unstable cervical injuries such as displaced odontoid fractures, burst fractures or tear drop fractures require surgical intervention. Thoracolumbar compression injuries without posterior wall involvement or significant kyphosis can be treated conservatively. Surgery is indicated in fractures-dislocations and burst fractures with significant canal narrowing and/or major kyphosis. The role of emergency decompression as well as that of steroids remain uncertain since no study to date has convincingly proven their efficacy.
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2004
Constantin Schizas, Pierre de Goumoëns, Bruno Fragnière (2004)  Rheumatoid arthritis of the cervical spine: surgical management   Rev Med Suisse Romande 124: 9. 575-578 Sep  
Abstract: Cervical spine involvement in patients suffering from rheumatoid arthritis significantly increases with time. This progression results in C1-C2 instability, vertical subluxation, subaxial spine subluxation or a combination of those three types of instability. It can remain asymptomatic or present with pain and/or neurological symptoms. Surgical treatment could be indicated in the presence of C1-C2 instability greater than 6 mm or even grater than 3 mm if there is associated vertical subluxation. Surgery can be associated with significant mortality and morbidity. In the presence of myelopathy surgical results can be particularly unfavourable with a mortality as high as 50%. It seems therefore important to proceed to surgical stabilisation quite early in order to prevent the onset of neurological involvement. Primary fusion extending to the upper thoracic spine should also be considered in selected patients in order to avoid the onset of caudal instability which can present with late development of progressive myelopathy.
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2003
Constantin Schizas, Caridad Ballesteros, Pratik Roy (2003)  Cauda equina compression after trauma: an unusual presentation of spinal epidural lipoma.   Spine (Phila Pa 1976) 28: 8. E148-E151 Apr  
Abstract: STUDY DESIGN: A case report is presented. OBJECTIVE: To describe a case of a spinal epidural lipoma presenting as a cauda equina compression syndrome secondary to trauma. SUMMARY OF BACKGROUND DATA: Epidural lipomas are rare lesions that present as back pain with progressive neurologic symptoms. METHODS: A patient presenting with cauda equina compression after an injury was investigated and treated surgically. The clinical follow-up period was 3 years. RESULTS: Imaging of the lumbar spine showed an extradural mass compressing the cauda equina. The patient underwent emergency surgery, and an adipose mass was removed. Neurologic recovery was observed and maintained 3 years after surgery. CONCLUSIONS: Previously asymptomatic epidural masses such as lipomas can present with neurologic deficit after trauma. Appropriate imaging can help in the diagnosis and management of such cases.
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2001
E Tsiridis, J Kohls-Gatzoulis, C Schizas (2001)  Avulsion fracture of the extensor carpi radialis brevis insertion.   J Hand Surg Br 26: 6. 596-598 Dec  
Abstract: Avulsion of the extensor carpi radialis brevis at wrist level is rare. We present a case of an avulsion fracture involving the extensor carpi radialis brevis insertion at the base of the middle finger metacarpal.
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1998
C G Schizas, I A Kramers-de Quervain, E Stüssi, D Grob (1998)  Gait asymmetries in patients with idiopathic scoliosis using vertical forces measurement only.   Eur Spine J 7: 2. 95-98  
Abstract: This study aimed at identifying measurable asymmetries during gait and relating them to the spinal deformity in subjects with idiopathic scoliosis. We investigated 21 patients aged between 10 and 26 years for gait asymmetries using force plates. All subjects completed five walking cycles over two force plates measuring vertical ground reaction forces. Among the parameters measured were contact time and magnitude of the two peaks of the vertical forces as well as the rate of application of those forces. Published gait data on normal subjects were used as a control group. In 20 subjects an asymmetry of at least one gait parameter was noted. Multiple regression analysis showed, however, that there was no relation between the noted gait asymmetry and the curve direction, curve magnitude or vertebral rotation. This suggests that although functional asymmetries of the central nervous system have been described in patients with idiopathic scoliosis, they do not appear to have a reproducible effect on gait.
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1995
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