Comparison between total disc replacement and hybrid construct at two lumbar levels with minimum follow-up of two years.

INTRODUCTION: Lower back pain due to degenerative disc disease is a therapeutic challenge in young patients. Although arthrodesis is currently the gold standard for surgical treatment, improvement in total disc replacement techniques makes it possible to preserve segmental mobility with good results in one-level surgery. Nevertheless, the French National Health Authority does not recommend total disc replacement for multilevel surgery. Thus, hybrid constructs that combine one-level disc replacement with arthrodesis have been developed for multilevel indications. HYPOTHESIS: The outcome of two-level lumbar disc arthroplasty does not differ from hybrid constructs. METHODS: The clinical and radiographic outcomes of disc arthroplasty were compared to hybrid constructs for two-level degenerative disc disease in 72 patients after a continuous follow-up of at least 2 years. The patients were divided into two groups that were similar for the indication and type of implants. RESULTS: There was no statistical difference in pain relief (-3.9 points versus -3.5 points for lumbar VAS) or reduction in ODI (-29.5% versus -27.0%) between TDR and hybrid constructs, respectively. There was no statistical difference in range of motion at the level of arthroplasty (8.4° versus 7.6°) and no kinematic dysfunction was identified. The re-operation rate at two years for persistent lumbar pain was respectively 6.7% for two-level disc arthroplasty and 4.3% for hybrid constructs. The complication rate was 4.8% and 8.7% respectively. DISCUSSION: No difference was found in this comparison of two homogeneous series between two-level disc arthroplasty and hybrid constructs for the treatment of degenerative disc disease after two years of follow-up. Two-level disc arthroplasty may be an alternative for young patients depending on an evaluation of long-term results. LEVEL OF EVIDENCE: Cohort observational study level III.

Does the type of sagittal spinal shape influence the clinical results of lumbar disc arthroplasty?

INTRODUCTION: It has been suggested that the indication for lumbar total disc replacement (LTDR) takes into account the local parameters, such as the type of disc disease demonstrated on MRI and the presence or absence of facet joint osteoarthritis. The type of preoperative sagittal curvature could also be taken into account. This study reports the clinical results of LTDRs depending on the type of sagittal spinal alignment. MATERIAL AND METHODS: Eighty patients were included in this prospective study, with a mean age of 41.7years (range, 27-56years). The clinical analysis took into account the lumbar VAS, the Oswestry Disability Index (ODI), and the preoperative frequency of painkiller use, at 1year and at the last follow-up. The satisfaction index, return to work, and willingness to undergo the same treatment were also collected. The radiological study included the analysis of lumbar-pelvic parameters to distribute the patients according to the Roussouly classification. RESULTS: The mean follow-up was 59.1months (range, 14-96months). The type 1 group included four cases. Reduction of the VAS, the ODI score, and the frequency of painkiller use at the last follow-up were significant in type 2 and 3 patients, and non-significant for type 4. Eighty-five percent of type 2 patients and 87.5% of type 3 patients were satisfied or very satisfied with the surgery versus only 68% of the type 4 patients. In addition, 63% of the type 4 patients declared they would be willing to undergo the same treatment again versus 85% of the type 2 patients and 82.5% of the type 3 patients. It should also be noted that 67% of the patients in this series returned to work. DISCUSSION AND CONCLUSION: This study underscores the influence of the type of sagittal curvature on the clinical results of LTDR, with type 4 patients showing inferior clinical results because of a higher rate of residual lower back pain. The indication in LTDR should be reconsidered for discogenic lower back pain in type 4 patients.

Intraoperative determination of lumbar prosthesis endplate lordotic angulation to improve motion.

The aim of total disc replacement (TDR) is to restore and maintain closer-to-physiology motion. Therefore, the factors that influence postoperative intervertebral motion have to be controlled. Factors such as disc height (DH), postoperative segmental lordosis (SL), implant design and positioning are still recognized to be influent. Otherwise, range of motion (ROM) distribution, between flexion and extension, appear to be influenced by obtaining parallel bearing surfaces, which depends on prosthesis endplate lordotic angulation. To assess in vivo the correlation between an intraoperative parameter (intraoperative segmental lordosis: ISL) and a postoperative parameter (postoperative segmental lordosis: PSL). To determine the advantage of ISL measurement on the improvement of the prosthetic endplate lordotic angulation choice. Radiological comparison between intraoperative and postoperative segmental parameters. Fifty-seven patients who received a TDR at one level, L4-L5 or L5-S1, with different prosthetic endplate lordotic angulations (0°, 5°, and 10°). Twenty-one consecutive patients underwent intraoperative measurement (ISL) on a lateral view, with a spacer at the mid-vertebral bony endplates (Group 1). ISL was correlated using a linear correlation test with PSL. Group 1 postoperative prosthesis endplate lordosis (PEL: angle between the bearing surfaces) were compared to those of 46 patients without intraoperative measurement (Group 2). The mean ISL and PSL angles were 12.2° (7-21°) and 13.9° (8-23°), respectively. We observed a strong linear correlation between ISL and PSL (r=0.78, P <0.006). In Group 1, PEL varied between -1° and 11°, and between -3.7° and 17.8° in Group 2. For 80% of the patients in Group 1, the PEL was less than 5°, versus 33% of the patients in Group 2. Only prostheses with PEL less than 5° had a preserved extension curve in ROM distribution (+3°). Intraoperative measurement of ISL has emerged as a key factor in predicting PSL in TDR. The percentage of parallel bearing surfaces was increased by a prosthesis endplate lordotic angulation choice guided by ISL measurement. This study confirmed the advantage of choosing the adequate lordotic angulation of the prosthesis endplate to restore a physiological motion distribution between flexion and extension.

Intraoperative neurophysiologic monitoring in spine surgery. Developments and state of the art in France in 2011.

Intraoperative spinal cord monitoring consists in a subcontinuous evaluation of spinal cord sensory-motor functions and allows the reduction the incidence of neurological complications resulting from spinal surgery. A combination of techniques is used: somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), neurogenic motor evoked potentials (NMEP), D waves, and pedicular screw testing. In absence of intraoperative neurophysiological testing, the intraoperative wake-up test is a true form of monitoring even if its latency long and its precision variable. A 2011 survey of 117 French spinal surgeons showed that only 36% had neurophysiological monitoring available (public healthcare facilities, 42%; private facilities, 27%). Monitoring can be performed by a neurophysiologist in the operating room, remotely using a network, or directly by the surgeon. Intraoperative alerts allow real-time diagnosis of impending neurological injury. Use of spinal electrodes, moved along the medullary canal, can determine the lesion level (NMEP, D waves). The response to a monitoring alert should take into account the phase of the surgical intervention and does not systematically lead to interruption of the intervention. Multimodal intraoperative monitoring, in presence of a neurophysiologist, in collaboration with the anesthesiologist, is the most reliable technique available. However, no monitoring technique can predict a delayed-onset paraplegia that appears after the end of surgery. In cases of preexisting neurological deficit, monitoring contributes little. Monitoring of the L1-L4 spinal roots also shows low reliability. Therefore, monitoring has no indication in discal and degenerative surgery of the spinal surgery. However, testing pedicular screws can be useful. All in all, thoracic and thoracolumbar vertebral deviations, with normal preoperative neurological examination are currently the essential indication for spinal cord monitoring. Its absence in this indication is a lost opportunity for the patient. If neurophysiological means are not available, intraoperative wake-up test is a minimal obligation.

Minimally invasive management of thoraco-lumbar fractures: combined percutaneous fixation and balloon kyphoplasty.

STUDY DESIGN: Retrospective review of prospectively collected data. BACKGROUND: There is no consensus regarding the ideal treatment of thoraco-lumbar spine fractures without neurological compromise. Many surgical techniques have been described but none has proved its definite superiority. The main drawback of these procedures is directly related to the morbidity of the approach. As minimally invasive fixation combined with balloon kyphoplasty for treatment of thoraco-lumbar fractures is gaining popularity, its efficacy has yet to be established. PURPOSE: The purpose of this study is to report operative data, clinical and radiological outcomes of patients undergoing minimally invasive management of thoraco-lumbar fracture at our institutions. METHODS: Forty-one patients underwent percutaneous kyphoplasty and stabilization for treatment of single-level fracture of the thoracic or lumbar spine. All patients were neurologically intact. There were 20 males and 21 females with an average age of 50 years. RESULTS: The mean follow-up was 15 months (3-90 months). The mean operative time was 102 minutes (range 35-240 minutes) and the mean blood loss was <100mL. VAS was significantly improved from 6.7 to 0.7 at last follow-up. Vertebral kyphosis decreased by 16° to 7.8° postoperatively (P<0.001). Local kyphosis and percentage of collapse were also significantly improved from 8° to 5.6° and from 35% to 16% at last follow-up. Fifteen leaks have been identified, three of which were posterior; all remained asymptomatic. No patient worsened his or her neurological condition postoperatively. CONCLUSION: Percutaneous stabilization plus balloon kyphoplasty seems to be a safe and effective technique to manage thoraco-lumbar fractures without neurological impairment.

Development of a per-operative procedure for concentrated bone marrow adjunction in postero-lateral lumbar fusion: radiological, biological and clinical assessment.

PURPOSE: Addition of bone marrow to the bone graft in the postero-lateral lumbar arthrodesis is a widely used technique. Bone marrow brings stem cells and growth factors contained in the platelets, favorable for bone growth. Adjunction of concentrated bone marrow should create better conditions and may increase bone growth. METHODS: Simple blind randomized clinical, prospective, monocentric trial was conducted. Fifteen patients underwent lumbar arthrodesis. During surgery, a fraction of the bone marrow harvested was centrifuged. One side received this concentrate with autologous bone and ceramics; the other side received the same graft with unconcentrated bone marrow. A quantitative study, realised with a volume calculating software on CT-scan images, determined the cortical bone volume in the graft post-operatively and at 3 months. The osteoprogenitor cells, nucleated cells and platelet concentrations were determined. RESULTS: The biological study found an average concentration of six times for the nucleated cells, 3.5 times for the platelets and 2.2 times for the osteoprogenitor cells. The comparison of the mean cortical bone volumes post-operatively and at 3 months was not significantly different. CONCLUSIONS: Despite the concentration obtained, there was no increase of bone growth by adding concentrated bone marrow. However, the number of stem cells in bone marrow was low and maybe a stronger concentration is needed to obtain a difference. The 3D reconstruction of the graft and the analysis of the graft's volume using a novel software was efficient according to the similarity of the graft's volume post-operatively in all patients.

Does thoracoscopic anterior release of rigid idiopathic scolioses associated with correction by posterior instrumentation result in better long-term frontal and sagittal balance?

INTRODUCTION: The aim of treatment of scolioses is to reduce deformities and restore balance in the spine. HYPOTHESES: In rigid forms of scoliosis, associating anterior release could provide greater frontal and/or sagittal plane correction and improve balance in the spine. PATIENTS AND METHODS: This study compared correction and long-term balance on two planes between two homogeneous groups of idiopathic rigid scolioses treated with and without thoracoscopic release. The study included rigid scolioses with less than 35% reducibility and a Cobb angle of more than 60°, who all underwent posterior correction using a rod rotation technique. There were 29 patients, 14 who underwent a one-step procedure (group A) and 15 a two-step procedure (group B), with the subgroups of kyphoscolioses and lordoscolioses determined in each group. Frontal balance, Cobb angle, thoracic kyphosis and the Jackson plumbline were measured on pre- and postoperative X-rays and at the final follow-up. RESULTS: The mean long-term final follow-up was 144 months for group A and 54 months for group B. Frontal plane correction was identical in groups A and B. Frontal balance was preserved in all cases at the final follow-up. Sagittal balance was not modified with or without anterior release. The thoracoscopic release step resulted in an additional correction of 15.5° (23%) of thoracic hyperkyphosis in patients with kyphoscoliosis (P=0.003). DISCUSSION: Thoracoscopy did not improve short term results in the Cobb angle or frontal or saggital balance. Nevertheless, enhanced correction of thoracic hyperkyphosis was obtained with this procedure. In this study, the association of thoracoscopic anterior release with posterior correction by rod rotation to treat rigid scolioses did not appear to improve results, except for the correction of thoracic hyperkyphosis.

Open wedge high tibial osteotomies: Calcium-phosphate ceramic spacer versus autologous bonegraft.

INTRODUCTION: Valgus tibial osteotomy (VTO) is a well-known procedure for the treatment of medial compartment femoro-tibial osteoarthritis. Good and very good results have been reported with calcium phosphate wedges, which avoid the inconveniences of autologous grafts use. The hypothesis of this study is that with equivalent results in the treatment of osteoarthritis of the knee, the use of calcium phosphate wedges (BMCaPh) to fill the bone defect created by osteotomy would result in fewer specific complications and less pain associated with autologous grafts (AUTO) harvesting. PATIENTS AND METHODS: This prospective, controlled, randomised study included one arm that received a macroporous, biphasic calcium phosphate wedge (BMCaPh group) and one arm that received an autologous tricortical graft (AUTO group) for filling. The same plate with locked screws was used for fixation in all cases. All patients underwent at least two years of clinical and radiographic post-operative follow-up. RESULTS: Forty patients were included. Loss of correction occurred in six of the twenty-two patients in the BMCaPh group (27%), resulting in three early surgical revisions, compared to one loss of correction in the AUTO group. Lateral cortical hinge tears were a risk factor for loss of correction for the entire cohort and in the BMCaPh group. (relative risk 13.3 [1.9-92]. Moreover, union took significantly longer and pain lasted significantly longer in the BMCaPh group, although results were comparable at 6 months. DISCUSSION: A significant number of undesirable events (loss of correction) occurred in this study, limiting the number of included patients. Nevertheless, the results show that although there was no difference in the two groups for overall complications, number of revisions all causes combined, or clinical results, filling with BMCaPh was less tolerated and increased the risk of loss of correction when local mechanical conditions of the knee were unfavourable (lateral cortical hinge tears). Moreover, although it is not possible to draw a conclusion because of methodology bias in this study, early weight-bearing resumption on the knee also seemed to favour these complications. LEVEL OF EVIDENCE: Level II. Prospective randomized study.

[Correction of stiff thoracic idiopathic adult scoliosis. Prediction from the traction radiograph]. / Réduction des scolioses idiopathiques raides de l'adulte.

PURPOSE OF THE STUDY: The aim of this study was to determine the predictive value of the traction radiograph in adults with stiff curve (preoperative Cobb angle>60 degrees and reduction of less than 35% with traction) thoracic scoliosis. We wanted to compare this predictive value with that observed in reducible scoliosis. MATERIAL AND METHODS: A traction radiograph was obtained using a standard protocol with dynamometric control of the force applied. Patients with stiff scoliosis had 47 thoracic curves and 11 thoracolumbar curves (with primary anterior release for ten thoracic curves and eight thoracolumbar curves) and patients with reducible scoliosis had 56 thoracic curves. Cortre-Dubousset instrumentation was used for treatment in all patients. RESULTS: The postoperative Cobb angle for the stiff curves (without anterior release) was strongly correlated with the preoperative angle with traction (r=0.91; p<0.0001). The correlation between the postoperative Cobb angle and the preoperative Cobb angle without traction was less pronounced (r=0.86; p<0.0001). The traction radiographs were less predictive of the Cobb angle correction than the postoperative Cobb angle. The difference was 17.5+/-7 degrees , which corresponds to a supplementary gain in reduction after surgery. For the thoracic curves alone, the differences between the traction Cobb angle and the postoperative Cobb angle was 14.5 degrees for stiff curves and 6.5 degrees for reducible curves. Furthermore, the correlation between the Cobb angle with traction and the postoperative Cobb angle was stronger for stiff curve thoracic scoliosis (r=0.90) than reducible thoracic scoliosis (r=0.78). DISCUSSION AND CONCLUSION: The standard traction radiographs were highly predictive of postoperative reduction of stiff thoracic and thoracolumbar curves treated by segmental instrumentation. The postoperative result can thus be estimated with a margin of error of +/-7 degrees . For the stiff curves, the postoperative Cobb angle was 17.5 degrees on average less than predicted on the traction radiograph (on average 20% supplementary gain in reduction). This angle gain, which was greater for stiff than reducible curves, corresponds to the determining effect of release occurring with stiff curves. Finally, because of the stronger correlation between the traction Cobb angle and the postoperative Cobb angle for stiff curves, the predictive value of the traction radiograph is greater for stiff curves than for reducible curves. In conclusion, one of the contributions of the traction radiograph, which results from the predictability of the postoperative angle with a small margin of error, is to enable adequate prediction of the postoperative outcome for a given patient or a specific sub-group of patients, e.g. with or without anterior release.

Influence of bone environment on ceramic osteointegration in spinal fusion: comparison of bone-poor and bone-rich sites.

Quantitative experimental data showed differences in bone quality and ceramic incorporation between bone-rich and bone-poor implantation sites. Bone in-growth was significantly lower for ceramic implanted at a lumbar intertransverse than a laminar site. Bone-marrow enrichment of the lumbar intertransverse site (regarded as bone-poor) greatly facilitated ceramic osteointegration. The vertebral interbody site, despite theoretical richness in osteogenic precursor cells, might be bone-poor at the time of grafting as compared to the reference iliac crest site. These data have important clinical implications concerning the potential benefit of enriching both bone-poor and bone-rich sites.

Intraspinal metallosis causing delayed neurologic symptoms after spinal instrumentation surgery.

STUDY DESIGN: Two cases of intraspinal metallosis causing delayed neurologic symptoms secondary to spinal instrumentation surgery are reported. OBJECTIVE: To present an unusual delayed neurologic complication after spinal instrumentation surgery. SUMMARY OF BACKGROUND DATA: Metal-related complications caused by orthopedic implants have long been a concern in the field of arthroplasty or internal fixation of fractures, but no such complications have been reported for spinal instrumentation. METHODS: Retrospective case report of two patients with degenerative scoliosis who presented with delayed neurologic symptoms months to years after uneventful, but without secondary degenerative changes or dislodgement of the implants. RESULTS: In both reported cases, a granulation-tissue mass characterized by marked metallosis had been formed in the spinal canal adjacent to a loosened laminar hook. CONCLUSIONS: Intraspinal metallosis should be kept in mind as a rare cause of delayed neurologic symptoms after spinal instrumentation surgery. With the metal implants in place, myelography was the sole informative examination for diagnosis.

[In vitro assessment of combining osteogenic cells with macroporous calcium-phosphate ceramics]. / Etude in vitro de l'association de cellules ostéogènes avec une céramique en phosphate de calcium macroporeuse.

PURPOSE OF THE STUDY: Bone grafts or bone substitutes are required to fill bone defects resulting from trauma or surgical resection of tumors. Calcium-phosphate ceramics are synthetic bone substitutes which promote new bone formation by osteoconduction. These ceramics possess osteoconductive properties but have no intrinsic osteoinductive capacity. They are unable to induce new bone formation in extraossesous sites. One solution to develop bone substitutes with osteogenic properties would be to associate biomaterials with osteoprogenitors. MATERIALS AND METHODS: We studied the in vitro osteogenic potential of human bone-marrow cells cultured on macroporous calcium phosphate (CaP) ceramic, examining stromal cell proliferation and differentiation. Osteogenic differentiation was evaluated in terms of alkaline phosphatase activity and immunological characterization of the extracellular fibrillar matrix formed by these cells. The specimens were examined by scanning and transmission electron microscopy. RESULTS: Human bone-marrow cells proliferated on CaP ceramic. The proliferating bone-marrow cells expressed an osteoblastic phenotype as shown by alkaline phosphatase activity and synthesis in ceramic pores of an extracellular matrix composed of fibronectin, osteocalcin and collagen I. In addition, numerous microcrystals of apatite precipitated on the fibrillar matrix, producing a mineralized fibrillar network within the ceramic. CONCLUSION: This study demonstrates that human bone-marrow cells cultured on macroporous CaP ceramic do not lose their osteoblastic phenotype even after 21 days of culture, and that they can induce osteogenesis in a CaP ceramic in vitro. This type of new "hybrid material" appears promising for the future.

Efficacy of nerve root versus interspinous injections of glucocorticoids in the treatment of disk-related sciatica. A pilot, prospective, randomized, double-blind study.

STUDY OBJECTIVES: Pilot study comparing the short-term efficacy on pain and functional impairment of nerve root sheath versus interspinous glucocorticoid injections in patients admitted to a French rheumatology department for disk-related sciatica or femoral neuralgia. PATIENTS AND METHODS: Thirty patients with refractory nerve root pain (sciatica, n = 29; femoral neuralgia, n = 1) for a mean of four months were randomized to nerve root injection (n = 17) or interspinous injection (n = 13) of the same mixture of 0.10 g of lidocaine hydrochloride and 3.75 mg of cortivazol. Both injection methods were performed under analgesia and benzodiazepine sedation to maintain double blinding. Each patient was evaluated daily during the first seven days of bed rest in the hospital, then after discharge on postinjection day 28. RESULTS: Prompt pain relief was obtained in both groups. On day 1, the mean pain scale score (0-100) fell from 70 +/- 3.9 to 26 +/- 5.6 in the nerve root group and from 63 +/- 4 to 23 +/- 4.7 in the interspinous group. These results were sustained on D7 and D28. CONCLUSIONS: The unusually high level of efficacy of glucocorticoid injection in our study may be ascribable in part to strong placebo and Hawthorne effects and in part to the intrinsic effects of the injections. Whether nerve root injection is superior over interspinous injection remains unproven.

A synthetic porous ceramic as a bone graft substitute in the surgical management of scoliosis: a prospective, randomized study.

STUDY DESIGN: A prospective randomized study. OBJECTIVES: To assess the clinical and radiologic performances of a synthetic ceramic as a bone graft substitute in scoliosis surgery. SUMMARY OF BACKGROUND DATA: Surgery on the skeleton frequently requires harvesting of autogenous bone grafts from the pelvis, but this procedure often is complicated by problems. METHODS: Fifty-eight patients with idiopathic scoliosis, ages 13 to 25 years, were treated by posterior correction and arthrodesis using Cotrel-Dubousset instrumentation. Posterior spinal fusion was performed using local bone grafts combined with autogenous iliac bone grafts in 30 patients, and combined with porous biphasic calcium phosphate ceramic blocks comprising hydroxyapatite and tricalcium phosphate in another 28 patients. The patients were observed for a minimum of 24 months after surgery, with a mean postoperative observation time of 48 months. The results were assessed clinically and radiographically. RESULTS: Patients in the ceramic group had a lower average blood loss than those in the iliac graft group. They also were free from postoperative local complications in the iliac region, which were experienced by a significantly high proportion of patients belonging to the iliac graft group. Radiography demonstrated successful incorporation of the ceramic blocks within 12 months. The correction of the deformity was maintained similarly and satisfactorily in both groups. CONCLUSIONS: These results justify and favor the use of calcium phosphate ceramics as bone graft substitutes for instrumented posterior spinal fusion in teenagers and young adults. Potentially hazardous harvesting of pelvic bone is no longer necessary for such operations.

[Neurogenic mixed evoked potential monitoring during scoliosis surgery: retrospective analysis of 149 cases]. / Utilisation des potentiels évoqués mixtes neurogènes durant la chirurgie des scolioses: analyse rétrospective à propos de 149 cas.

INTRODUCTION: We report a retrospective analysis of spinal cord monitoring with neurogenic mixed evoked potentials (NMEPs) combined with somatosensory evoked potentials (SSEPs) in 149 patients undergoing surgery for spinal deformity. MATERIAL AND METHODS: 149 patients (104 females and 45 males), mean age 28 yrs (13-72 yrs) were studied. NMEPs were elicited by electrical spinal cord stimulation in the rostral part of the surgical field, via two needle electrodes set in the epidural space and in the interspinous ligament above. They were recorded from the sciatic nerve at the knee and the sural nerve at the ankle. SSEPs were recorded from the scalp after stimulation of the posterior tibial nerve at the ankle. A decrease in amplitude of more than 50 p. 100 and/or an increase in latency of more than 10 p. 100 were defined as significant warning criteria. RESULTS: No false-negative result was observed. NMEP modifications did not reach critical value in 143 cases. In 6 cases, significant changes were observed. Moving the stimulation electrodes along the spinal cord allowed spinal lesion localization and helped the surgeon to perform the adapted maneuver, clearly avoiding the occurrence of postoperative neurological defect in 5 of the 6 cases. CONCLUSION: NMEP monitoring is a sensitive and specific method useful for detecting an impending lesion of the spinal cord. NMEPs are also helpful in localizing the spinal level of the lesion. They represent a primary choice tool for neuromonitoring during scoliosis surgery.

Successful monitoring of neurogenic mixed evoked potentials elicited by anterior spinal cord stimulation through thoracoscopy during spine surgery.

STUDY DESIGN: Neurogenic mixed evoked potentials were recorded after thoracoscopic spinal cord stimulation in patients undergoing video-assisted spine surgery. OBJECTIVE: To demonstrate the feasibility and value of thoracoscopic spinal cord monitoring. SUMMARY OF BACKGROUND DATA: Video-assisted thoracic surgery recently has been proposed as a new technique for thoracic spine surgery. It can be used for anterior spinal release of patients with severe spinal deformities and for thoracic hernia removal. METHODS: Five patients undergoing video-assisted thoracic surgery for spinal fusion were studied. Neurogenic mixed evoked potentials were elicited by electrodes seated into intervertebral discs through thoracoscopy and recorded from peripheral nerves of the lower limbs. Moreover, the study included the case of a patient with a thoracic hernia who underwent video-assisted thoracic surgery with combined thoracoscopic neurogenic mixed evoked potential and standard somatosensory evoked potential monitoring. RESULTS: Neurogenic mixed evoked potentials were recorded consistently after spinal cord stimulation in all patients. For the patient with a thoracic hernia, neurogenic mixed evoked potentials suddenly disappeared, whereas somatosensory evoked potentials were not significantly modified, leading to surgery interruption. Neurogenic mixed evoked potentials progressively reappeared after a 30-minute delay. Postoperation examination revealed a Brown-Sequard's syndrome with incomplete right motor deficit. CONCLUSIONS: Neurogenic mixed evoked potentials evoked by anterior stimulation through thoracoscopy are of interest for spinal cord monitoring when posterior electrical stimulation is impossible, and they provide reliable information regarding spinal motor pathways.

[Neurologic complications of surgical treatments]. / Les complications neurologiques des traitements chirurgicaux.

Neurological complications during correction of scoliosis remain a rare but very severe event. Prevention by analysis of risk factors pre-operatively and assessment of complications per-operatively could be done using wake-up test and evoked potential monitoring, to emphasize short term prevention of these complications. A clear information must be given to the patient and his family before such an operation.