Analysis of cervical sagittal alignment variations after lumbar pedicle subtraction osteotomy for severe imbalance: study of 59 cases.

OBJECTIVE: To evaluate postoperative changes within the cervical alignment following surgical lumbar correction by pedicle subtraction osteotomy (PSO) in patients affected with sagittal global malalignment disease. METHODS: This was a monocentric, radiographic, and prospective study. 79 patients, who underwent sagittal correction by PSO, performed an EOS imaging pre- and postoperatively between January 2008 and December 2013 at the University Hospital of Bordeaux. Inclusion criteria were a performed pre- and postoperative EOS imaging and a preoperative C7SVA > 5 cm. Were excluded patients who did not allow EOS with a viewable cervical spine due to hyperkyphosis. The study involved the analysis of pelvic, lumbar, thoracic, cervical, and cranial parameters before and after the surgery. RESULTS: 59 patients met the criteria. Mean follow-up was 38 months. The lumbar PSO significantly improved sagittal alignment including L1S1 lordosis, T1T12 kyphosis, and C7SVA (p < 0.001). We did not reported a significant change within cervical parameters after PSO (C2C7 lordosis 22.7°-21.5° p = 0.64, C1C7 lordosis 50.6°-48.8° p = 0.56, C1C2 angle 28.2°-27.9° p = 0.82, C7 slope stayed constant 32.3°-30.5° p = 0.47, OC2 angle 15.54°-15.56° p = 0.99). However, cranial slope decreased significantly (p < 0.05). We did not find correlation between lumbar lordosis and cervical lordosis variations (R = 0.265). Cervical lordosis was highly correlated with the C7 slope (R = 0.597) and with the Spino Cranial Angle (R = - 0.867). CONCLUSION: Reciprocal changes in cervical spine after PSO are difficult to approach. Maintaining a horizontal gaze involves locoregional mechanisms of compensation adapting to the slope of C7. The cranial system by decreasing the cranial slope allows the gaze alignment and is the first compensation mechanism to get involved after a loss of lumbar lordosis. Restoring optimal C7SVA is necessary to prevent the development of secondary cervical painful symptomatology when the cranial compensation is outdated.

Maverick total disc arthroplasty performs well at 10 years follow-up: a prospective study with HRQL and balance analysis.

PURPOSE: The treatment of low back pain associated to Disc Degenerative Disease (DDD) is still controversial. Segmental Fusion is the gold standard, but many studies have reported that motion-preserving devices bring substantial clinical benefits to patients. Concerns on the associated complications and on the long-term clinical effectiveness of such instrumentations are still present and have led recently to a decrease of the number of Lumbar Total Disk Replacements (TDR). The objective of this prospective study is to present the clinical and radiographic outcomes of the Maverick Lumbar disk prostheses (Medtronic, TE, Memphis, USA) at long-term follow-up. METHODS: Prospective, single center study of clinical outcome of the treatment with Maverick lumbar Prosthesis of patients with low back pain from DDD resistant to conservative treatment. Patients were examined preoperatively and at 3 months, 2 and 10 years post-operatively. Patients were examined preoperatively and at 3 months, 2 and 10 years post-operatively. Visual analog scale (VAS), Oswestry disability index (ODI) and 36-Item Short Form Health Survey questionnaire were assessed to study clinical outcomes. Radiographic studies allowed measurements of range of motion, adjacent segment disease and pelvic and lumbar parameters. RESULTS: From an initial cohort of 87 patients who underwent TDR between 2003 and 2007 with the Maverick prosthesis, 61 were available at Final follow-up (70%). The clinical outcomes measured by VAS and ODI showed a significant improvement in all the postoperative stages of the follow-up (FU). At 10 years-FU, ODI experienced a mean decrease of 21.1 points, VAS for back pain decreased up to 3.85 and substantial clinical benefit was reached for 55.6% of the patients. Although Mobility of the prosthesis was preserved in 76.8% of the cases, TDR was not clearly protective against ALD. CONCLUSIONS: A significant, clinically relevant, and lasting reduction of back pain has been achieved in patients who underwent a total disk arthroplasty or a Hybrid construct with Maverik prosthesis. TDR is a safe and effective technique to decrease pain in patients with one or two levels of DDD.

Meta-analysis of the effects of genetic polymorphisms on intervertebral disc degeneration.

INTRODUCTION: Chronic low back pain is a significant public health issue. Both its direct and indirect cost represents tens of billions of US dollars. Although chronic low back pain can be the result of many factors, the predominant cause is disc degeneration. Recent studies have shown genetic involvement in up to 74% of cases. This study aimed to evaluate genetic risk factors of disc degeneration by performing a systematic analysis of association studies. The objective is to provide a guide for practice by assessing the clinical relevance of current information. METHODS AND MATERIALS: We performed a meta-analysis of 3122 items collected from 6 databases. 74 articles were selected according to our inclusion criteria. 18 (24%) could be grouped into 16 meta-analyses of 16 mutations in 12 genes. The statistics of the meta-analysis were conducted through Revman 5.1 software. RESULTS: The items included are 10,250 cases and 14,136 controls. The GOLD range from 3.42 to 0.38. Two alleles were significantly associated with disc degeneration: IL-6 rs1800797 and MMP-9 rs17576 and one proved to be protective: IL-6 rs1800795. 13 meta-analyses did not yield significant results and methodological heterogeneity. DISCUSSION: The results highlight the lack of methodological rigor in most of the studies. The absence of international clinical and radiological classification of early disc degeneration, limits the homogeneity of studies. Understanding which populations are predisposed to this significant public health problem may change our approach to diagnostic and therapeutic methods. This work opens up enormous opportunities to provide a genetic solution and consider new diagnostic and therapeutic means to this public health problem.

Lumbar scoliosis associated with spinal stenosis in idiopathic and degenerative cases.

UNLABELLED: Degenerative de novo scoliosis is commonly present in older adult patients. The degenerative process including disc bulging, facet arthritis, and ligamentum flavum hypertrophy contributes to the appearance of symptoms of spinal stenosis. Idiopathic scoliosis has also degenerative changes that can lead to spinal stenosis. PURPOSE: The aetiology, prevalence, biomechanics, classification, symptomatology, and treatment of idiopathic and degenerative lumbar scoliosis in association with spinal stenosis are reviewed. STUDY DESIGN: Review study is based on a review of pertinent but non-exhaustive literature of the last 20 years in PubMed in English language. METHODS: Retrospective analysis of studies focused on all parameters concerning scoliosis associated with stenosis. RESULTS: Very few publications have focused specifically on idiopathic scoliosis and stenosis, and this was before the advent of modern segmental instrumentation. On the other hand, many papers were found for degenerative scoliosis and stenosis with treatment methods based on aetiology of spinal canal stenosis and analysis of global sagittal and frontal parameters. Satisfactory clinical results after operative treatment range from 83 to 96 % but with increased percentage of complications. Recent literature analysed the importance of stabilizing or not the spine after decompression in such situation knowing the increasing risk of instability after facet resection. No prospective randomized studies were found to support short instrumentation. Long instrumentation and fusion to prevent distabilization after decompression were always associated with higher complication rates. Imbalance patients with unsatisfactory compensation capacities were at risk of complications. CONCLUSIONS: Operative treatment using newly proposed classification system of lumbar scoliosis with associated canal stenosis is useful. Sagittal balance and rotatory dislocation are the main parameters to analyse to determine the length of fusion.

Clinical and radiological outcomes of lumbar posterior subtraction osteotomies are correlated to pelvic incidence and FBI index : Prospective series of 63 cases.

PURPOSE: Pedicle subtraction osteotomy (PSO) is one of the surgical options for treating alignment disorders of the fused spine (due to post-surgical fusion or related to arthritis). It enables satisfactory sagittal realignment and improved function due to economic sagittal balance. The aim of this study was to analyze clinical and radiological results of PSO after a minimum follow-up of 2 years and demonstrate the benefit of sub-group analysis as a function of pelvic incidence (PI). METHODS: A descriptive prospective single center study of 63 patients presenting with spinal global malalignment who underwent correction by PSO. Function was assessed by the Oswestry disability index (ODI), a visual analog scale of lumbar pain (VAS) and a SF-36 questionnaire. Radiographic analyses of pre- and post-operative pelvic-spinal parameters were performed on X-rays obtained by EOS(®) imaging after 3D modeling. Global analysis and analysis of sub-groups as a function of pelvic incidence were performed and the full balance integrated index (FBI) was calculated. RESULTS: this series showed a marked clinical improvement and significant progress of functional scores. Global post-operative radiological analysis showed a significant improvement in all pelvic and spinal parameters. The mean correction obtained after PSO was 31.7° ± 8.4°, hence global improvement of lumbar lordosis of 22°. The sagittal vertical angle (SVA) decreased from +9 cm before surgery to +4.3 cm after surgery. Sub-group analysis demonstrated greater improvement in pelvic tilt, sacral slope and spinal parameters of patients with a small or moderate pelvic incidence; all had an FBI index <10°. Most of the pelvic and spinal parameters of patients with a large pelvic incidence were insufficiently corrected and they had an FBI index >10° CONCLUSION: PSO is a surgical procedure enabling correction of multiplane rigid spinal deformities that require major sagittal correction. It was seen to be highly effective in patients with a small or moderate pelvic incidence (PI <60°) but was sometimes less effective in patients with large pelvic incidence due to insufficient lordosis correction. Clinical results were highly correlated with the value of the FBI index.

Normative values for the L5 incidence in a subgroup of transitional anomalies extracted from 147 asymptomatic subjects.

PURPOSE: Pelvic incidence angle is not always measurable due to lumbosacral transitional vertebrae (LSV). The fifth lumbar vertebra (L5) is rarely abnormal. The purpose of this study was to quantify from full-body standing X-rays, the L5 incidence angle (L5I) in a normal asymptomatic population and to correlate it with standard spino-pelvic parameters taking the sacrum (S1) as a reference. METHODS: One hundred and forty seven asymptomatic volunteers were enrolled. The ethics committee approved the study protocol. Subjects underwent a low-dose full spine X-ray. 3D reconstructions were obtained and L5I was measured using the upper L5 endplate as the reference instead of the S1 endplate. A group of subjects with LSV was identified and subdivided in two subgroups. Standard spino-pelvic parameters and normative values for the L5 parameters were obtained. Statistical correlations were calculated between the standard and L5 parameters as well as L5I with L1-L5 lordosis in both subgroups. RESULTS: Twenty two (14.96 %) subjects with LSV were found. Ten of these had an unidentifiable S1 endplate due to a sacralisation of L5. Mean values for the L5I, L5 tilt, L5 slope and L1-L5 lordosis were, respectively, 22.43, 4.65, 17.73, and 45.51 for normal subjects (N = 137) and 32.75, 6.63, 26.38, and 55.02 for sacralisation of L5 subjects (N = 10). Mathematical relationship found: L5I = 0.7641 * PI - 17.725 (R = 0.83) and L1-L5 = 0.67 * L5I + 30.7 (R = 0.64). CONCLUSION: This prospective study is first to provide normative spino-pelvic values at the L5 level in an asymptomatic population, particularly in case of (LSV) sacralisation of L5 (N = 10) where L5I and L1-L5 lordosis appears to be 10° more important than in normal population. We propose L5I as a new spino-pelvic parameter to restore in case of L5-S1 disk disease. These normative values will help to control peri-operatively the adequate lordosis restoration, in the presence of LSV.

Pedicle subtraction osteotomy in the thoracic spine and thoracolumbar junction: a retrospective series of 28 cases.

PURPOSE: Pedicle subtraction osteotomy is a well-described surgical technique for treatment of kyphotic deformity in the spine. It is not widely used for treatment of thoracic kyphosis. We present the first documented series of 28 patients who underwent this procedure in 3 international centers. These patients presented with severe deformity with a wide range of aetiologies. INDICATIONS: Kyphosis larger than 70 degrees, which is demonstrably rigid based on dynamic imaging. MATERIALS AND METHODS: 28 patients underwent surgery following pre-op neurological and radiographic assessment to fully assess the deformity. A triangular osteotomy was carried out using intraoperative navigation techniques. The patients were assessed post-operatively again with clinical and radiographic parameters at regular follow-up. RESULTS: The mean ODI score after surgery was 24.7 (16-42) while the pre-op was 53.4 (38-76). Mean thoracic kyphosis was improved from 64.2° (±20.1°) to 41.1° (±17.4°) resulting in a mean sagittal correction of 23.1°. Mean segmental correction at the PSO for all 28 cases was 17.8° (±8.1°). Stratified by region we found different values for the PSO correction: between T1 and T5 (6 cases) it was 17.5° (±5.4°) and between T6 and T9 (4 cases) 18.2° (±4.7°) and between T10 and L1 (18 cases) 26.2° (±5.2°). FBI index was 22.3° pre-op and improved to 7.8° post-op. Calculations were performed with Microsoft excel (2011 Microsoft, Redmond, WA). CONCLUSIONS: Global sagittal balance was statistically improved in this series as demonstrated by FBI and C7 SVA correction.

Insufficient restoration of lumbar lordosis and FBI index following pedicle subtraction osteotomy is an indicator of likely mechanical complication.

PURPOSE: Pedicle subtraction osteotomies (PSO) enable correction of spinal deformities but remain difficult and are associated with high complication rates. This study aimed to prospectively review different post-operative complications and mechanical problems in patients who underwent PSO as treatment for sagittal imbalance as sequelae of degenerative disc disease or previous spinal fusion. METHOD: This was a descriptive prospective single center study of 63 patients who underwent sagittal imbalance correction by PSO. Radiographic analysis of pre- and post-operative pelvic and spinal parameters was completed based on EOS images following 3D modeling. Global and sub-group analyses were completed based on the Roussouly classification. A systematic analysis of post-operative complications was conducted during hospital stay and at follow-up visits. RESULTS: Complications included 15 cases (20.2%) of bilateral leg pain, with transient neurological deficit in 6 cases (9.5%), and 9 cases (12.5%) of early surgical site infections. Intra-operative complications included five tears of the dura mater and two cases of excessive blood loss (>5,000 mL). Two mortalities occurred from major intracerebral bleeds in the early post-operative period. Mechanical complications were principally non-union (9 cases) and junctional kyphosis (3 cases). All 19 post-operative complications (28.1%) were revised at an average of 2 years following surgery. All mechanical complications were found in the patients who had insufficient imbalance correction and this was mainly associated with high PI (>60°) or a moderate PI (45-60º) combined with excess FBI pre-operatively that remained >10° post-operatively. CONCLUSION: Infection and neurologic complications following PSO are relatively common, and frequently reported in the literature. The principal cause of mechanical complications, such as non-union or junctional kyphosis, was insufficient sagittal correction, characterized by post-operative FBI >10°. The risks of insufficient correction are greater in patients with higher pelvic incidence and those patients who required very high correction.

Adjacent segment disease after anterior cervical interbody fusion: a multicenter retrospective study of 288 patients with long-term follow-up.

INTRODUCTION: Cervical discectomy with interbody fusion is a common procedure in spinal surgery. The resultant biomechanical alterations accelerate degeneration of the adjacent segment, but the contribution of natural degeneration to adjacent segment disease is unclear. OBJECTIVE: To assess the long-term rate of surgery to discs adjacent to cervical interbody fusion; and to assess the associated incidence of cervico-brachial neuralgia and radiological degeneration of adjacent discs. MATERIAL AND METHOD: A multicenter retrospective study included anterior cervical discectomy patients at a minimum of 10 years' follow-up. Clinical variables comprised pain, use of analgesics and surgical revision. Functional assessment was performed on the Neck Disability Index (NDI). Radiologic degeneration was assessed on the Goffin score based on cervical spine X-ray. RESULTS: Two hundred and eighty-eight patients were contacted and filled out the clinical questionnaire. Among the patients, 153 underwent radiological reassessment. Mean age was 46 years (range, 16-73 years). Mean follow-up was 14.5 years (12-18 years). The rate of surgical revision on a disc adjacent to the primary level was 5.9%. Frequent attacks of cervico-brachial neuralgia were reported in 20.5% of cases. Radiologic adjacent segment degeneration was found in 81.3% of cases over follow-up. There was a significant correlation between degree of radiologic adjacent segment degeneration and NDI (P=0.02). DISCUSSION: Degeneration adjacent to discectomy/fusion is partly due to aging. The present findings, however, agree with the literature and indicate accelerated degeneration in adjacent segments. These findings should be taken into account in treatment decision-making and suggest a possible interest of more physiological surgery such as arthroplasty. LEVEL OF EVIDENCE: IV - Multicenter retrospective study.