Influence of Posture on Gait Parameters in Severe Symptomatic Lumbar Stenosis Before and After Decompression Surgery.

BACKGROUND: We searched to quantify the influence of sagittal vertical axis (SVA) on the improvement of spatiotemporal gait parameters using a gait motion analysis (GMA) before and after decompression surgery in patients suffering from lumbar spinal stenosis (LSS). METHODS: Thirty-nine patients with severe LisSS planned for lumbar decompression underwent a full-body biplanar radiographs (EOS) to quantify the SVA and have benefited from a 3-dimensional GMA 1 month before surgery (M0) and 6 month (M6) after surgery. The first step of this study was to confirm the validation of 3-dimensional sagittal vertical axis (3D SVA) for posture analysis. An analysis of modification of the 3D SVA and spatiotemporal gait parameters was then carried out in order to identify any correlation. RESULTS: Decompression surgery did not significantly improve 3D SVA between M0 and M6 (respectively 49.1 [50.3] vs. 49.84 [19.02], P = 0.42). Concerning spatiotemporal parameters, we found significant difference for all parameters between M0 and M6. A strong correlation (R2 > 0.65) between static SVA (EOS) and 3D SVA was demonstrated using a statistical regression equation. There was also a statistically significant correlation between SVA (static and 3-dimension) and improvement in spatiotemporal gait parameters after decompression surgery. CONCLUSIONS: This study analyses the relationship between postural change (SVA) and improvement in gait parameters measured during GMA before and after decompression surgery for LSS. This specific analysis of gait parameters may represent a prognostic assessment tool for the recovery of patients undergoing surgery for a LSS.

Observational, Multicenter Study of the Efficacy and Safety of Cervical Disk Arthroplasty With Mobi-C in the Treatment of Cervical Degenerative Disk Disease. Results at 10 years Follow-Up.

BACKGROUND: Cervical disk arthroplasty replacement (CDA) was developed to avoid specific disadvantages of cervical fusion. The purpose of this paper is to provide 10-year follow-up results of an ongoing prospective study after CDA. METHODS: Three hundred eighty-four patients treated using the Mobi-C (ZimVie, Troyes, France) were included in a prospective multicenter study. Routine clinical and radiologic examinations were reported preoperatively and postoperatively with up to 10-year follow-up. Complications and revision surgeries were also documented. RESULTS: At 10 years showed significant improvement in all clinical outcomes [Neck Disability Index, visual analog scale (VAS) for arm and neck pain, physical component summary of SF36, and mental component summary of SF36). Motion at the index level increased significantly over baseline (mean range of motion=7.6 vs. 8 degrees at five years and 6.0 degrees preoperatively; P <0.001) and 71.3% of the implanted segments remained mobile (range of motion>3 degrees). Adjacent disks were also mobile at 10 years with the same mobility as preoperatively. At 10 years, 20.9% of the implanted segments demonstrated no heterotopic ossification. Thirty-four patients (8.9%) experienced 41 adverse events, with or without reoperation during the first five years. We found only two additional surgeries after five years. We observed an increased percentage of working patients and a decrease in medication consumption. Regarding the overall outcome, 94% of patients were satisfied. CONCLUSIONS: Our 10-year results showed significant improvement in all clinical outcomes, with low rates of revision or failure. This experience in patients with long-term follow-up after CDA endorses durable, favorable outcomes in properly selected patients.

Walking Speed as an Alternative Measure of Functional Status in Patients with Lumbar Spinal Stenosis.

OBJECTIVE: The main objective was to compare estimated walking perimeter (WP) and actual WP during a free walking test (6-minute walk test [6MWT]) in patients with lumbar spinal stenosis (LSS). The second objective was to describe the correlation between measured gait parameters and functional parameters. METHODS: This was a single-center prospective study including 38 patients with symptomatic LSS (23 men, 15 women; mean age, 69.3 ± 7.9 years). The intervention was the 6MWT. For the main outcome measure, patients were first asked to verbally estimate their WP. Then, WP was evaluated using a 6MWT at a self-selected speed. In the absence of need to stop, and if a distance of 500 m was not reached, the test was extended to this distance. Specific functional scores (Oswestry Disability Index and Quebec Back Pain Disability Scale) were recorded, and a quality of life questionnaire was completed. RESULTS: WP was estimated to be less than 500 m in 21 of 38 patients, but only 7 patients actually stopped walking before reaching 500 m. The median estimate error in these patients was 200 m (interquartile range, 65-250). The shorter the estimated distance was, the greater the estimation error (r = -0.63, P=0.002). The average walking speed was slow. Functional parameters (Oswestry Disability Index and Quebec Back Pain Disability Scale) were weakly and inversely correlated with real WP (r = -0.44 and r = -0.31, respectively) and moderately inversely correlated with measured walking speed (r = -0.51, P = 0.001 for both). CONCLUSIONS: Direct measurement of free walking speed should be considered as a valid functional assessment in current practice for patients with LSS instead of estimated WP. To assist therapeutic decision-making, the most relevant type of walking test (duration, distance, velocity) needs to be determined.

Rare Complication of Percutaneous Technique: Intradural Cement Leakage and Its Surgical Treatment.

Popularity of percutaneous vertebroplasty and vertebral augmentation to treat vertebral compression fractures is increasing. Cement leakages are relatively common, but intradural cement leakage is rare. Few cases of intradural cement leakage have been reported in the literature, and emergency surgery has been reported to be <1%. A 64-year-old man with osteolytic vertebral compression fracture at L1, caused by a malignant tumor, had undergone a vertebral augmentation by craniocaudal procedure. Neurologic examination after the surgery revealed paralysis in both legs immediately postoperatively. Computed tomographic imaging revealed a large cement leakage into the spinal canal. The patient was referred to our department for emergency management. He was rapidly scheduled for surgical decompression by laminectomy. First, stabilization by a secure posterior short fixation was done. The laminectomy showed that insertion of a needle through the pedicle had breached the dura and had caused intradural cement leakage. As shown in the Supplementary Video, the piece of intradural cement was finally removed after posterior durotomy. This case demonstrates that even if percutaneous vertebroplasty is a relatively safe technique, it should be performed by well-trained physicians and with great care to prevent disabling complications.

Surgeon's and patient's radiation exposure during percutaneous thoraco-lumbar pedicle screw fixation: A prospective multicenter study of 100 cases.

HYPOTHESIS: Percutaneous pedicle screw fixations (PPSF) are increasingly used in spine surgery, minimizing morbidity through less muscle breakdown but at the cost of intraoperative fluoroscopic guidance that generates high radiation exposure. Few studies have been conducted to measure them accurately. MATERIAL AND METHODS: The objective of our study is to quantify, during a PPSF carried out in different experimented centers respecting current radiation protection recommendations, this irradiation at the level of the surgeon and the patient. We have prospectively included 100 FPVP procedures for which we have collected radiation doses from the main operator. For each procedure, the doses of whole-body radiation, lens and extremities were measured. RESULTS: Our results show a mean whole body, extremity and lens exposure dose per procedure reaching 1.7±2.8µSv, 204.7±260.9µSv and 30.5±25.9µSv, respectively. According to these values, the exposure of the surgeon's extremities and lens will exceed the annual limit allowed by the International Commission on Radiological Protection (ICRP) after 2440 and 4840 procedures respectively. CONCLUSION: Recent European guidelines will reduce the maximum annual exposure dose from 150 to 20mSv. The number of surgical procedures to not reach the eye threshold, according to our results, should not exceed 645 procedures per year. Pending the democratization of neuronavigation systems, the use of conventional fluoroscopy exposes the eyes in the first place. Therefore they must be protected by leaded glasses. LEVEL OF PROOF: IV, case series.

Improvement in Sagittal Balance After Decompression Surgery without Fusion in Patients with Degenerative Lumbar Stenosis: Clinical and Radiographic Results at 1 Year.

OBJECTIVE: To evaluate modifications in static spinal status after posterior decompression surgery without fusion in patients with symptomatic central canal stenosis. METHODS: From November 2014 to May 2016, 72 patients who underwent isolated decompression for lumbar spinal stenosis were enrolled prospectively in this single-center study. All of the patients had lateral full-body x-ray scans with the EOS system (EOS Imaging, Paris, France) before surgery and after 12 months of follow-up. Patients were classified into 3 groups according to their preoperative sagittal vertical axis (<50 mm, ≥50 mm, and <100 mm, ≥100 mm). RESULTS: SVA decreased significantly (SVA preoperative: 72.3 ± 43.1; SVA postoperative: 48.3 ± 46.8. P < 0.001). Lumbar lordosis increased significantly from 41.9 ± 13.4 in the preoperative period to 46.5 ± 14.8 at the last follow-up (P < 0.001). In the imbalance groups, the mean postoperative SVA decreased significantly compared with preoperative SVA (P = 0.004). Surgery led to a significant increase in lumbar lordosis in the 3 groups (P < 0.05). Nonetheless, a certain degree of residual imbalance persisted in the major imbalance group. In all of the groups, decompression surgery led to a significant improvement in clinical scores (P < 0.05). CONCLUSIONS: Our study showed an improvement in sagittal balance and lumbar lordosis after decompression surgery without fusion, even in patients with a preoperative SVA >100 mm. However, a certain degree of sagittal imbalance may persist after surgery in patients with major initial imbalance (SVA >100 mm). Nonetheless, after surgery, these patients experienced a clinical benefit comparable with that in the other groups.

Stand-alone ALIF with integrated intracorporeal anchoring plates in the treatment of degenerative lumbar disc disease: a prospective study on 65 cases.

PURPOSE: ALIF with cages is expected to restore disc height and stabilize the spine promoting fusion, while avoiding damage attributed to rod-pedicle screw fixation. However, it may be related to an increased risk of fusion failure and subsidence. A prospective study was conducted by five investigators across three centers to confirm performance of a PEEK cage for stand-alone ALIF in the treatment of lumbar degenerative disc disease (DDD). METHODS: Sixty-five patients, with back ± leg pain, requiring surgery for DDD, were included. Efficacy and safety were evaluated at 6 weeks, 3, 6, and 12 months post-operatively. Fusion and subsidence were assessed through CT-images at 12-month follow-up. Disc height was measured. Clinical outcomes included back and leg pain (VAS), disability (Oswestry Disability Index), Quality of Life (Short-Form 36), and adverse events. RESULTS: The fusion and the subsidence rates were 96.3 and 2.0 %, respectively. ALIF surgery restored anterior and posterior disc height compared to baseline. There were no device-related serious adverse events, and no revision surgeries. Clinical outcomes improved significantly through 12-month follow-up. CONCLUSION: Safety and efficacy of this stand-alone cage with integrated intracorporeal plates was confirmed through 12 months for treatment of degenerative conditions. The design of the cage and plates may contribute to the decreased subsidence rate observed.

Effects of lumbar artificial disc design on intervertebral mobility: in vivo comparison between mobile-core and fixed-core.

Although in theory, the differences in design between fixed-core and mobile-core prostheses should influence motion restoration, in vivo kinematic differences linked with prosthesis design remained unclear. The aim of this study was to investigate the rationale that the mobile-core design seems more likely to restore physiological motion since the translation of the core could help to mimic the kinematic effects of the natural nucleus. In vivo intervertebral motion characteristics of levels implanted with the mobile-core prosthesis were compared with untreated levels of the same population, levels treated by a fixed-core prosthesis, and normal levels (data from literature). Patients had a single-level implantation at L4L5 or L5S1 including 72 levels with a mobile-core prosthesis and 33 levels with a fixed-core prosthesis. Intervertebral mobility characteristics included the range of motion (ROM), the motion distribution between flexion and extension, the prosthesis core translation (CT), and the intervertebral translation (VT). A method adapted to the implanted segments was developed to measure the VT: metal landmarks were used instead of the bony landmarks. The reliability assessment of the VT measurement method showed no difference between three observers (p < 0.001), a high level of agreement (ICC = 0.908) and an interobserver precision of 0.2 mm. Based on this accurate method, this in vivo study demonstrated that the mobile-core prosthesis replicated physiological VT at L4L5 levels but not at L5S1 levels, and that the fixed-core prosthesis did not replicate physiological VT at any level by increasing VT. As the VT decreased when the CT increased (p < 0.001) it was proven that the core mobility minimized the VT. Furthermore, some physiologic mechanical behaviors seemed to be maintained: the VT was higher at implanted the L4L5 level than at the implanted L5S1 level, and the CT appeared lower at the L4L5 level than at the L5S1 level. ROM and motion distribution were not different between the mobile-core prosthesis and the fixed-core prosthesis implanted levels. This study validated in vivo the concept that a mobile-core helps to restore some physiological mechanical characteristics of the VT at the implanted L4L5 level, but also showed that the minimizing effect of core mobility on the VT was not sufficient at the L5S1 level.

Radiological analysis of 37 segments in cervical spine implanted with a peek stand-alone device, with at least one year follow-up.

BACKGROUND: High incidence of subsidence in cervical stand-alone cages was reported in the literature. PURPOSE: The goal of this study was to assess the radiological outcomes of a PEEK anchored stand-alone cage (MC+®) with a minimum of 1 year follow-up. STUDY DESIGN: A retrospective radiological evaluation. PATIENT SAMPLE: The study was conducted in 4 hospitals and involved 28 patients (37 levels) treated by ACDF (Anterior Cervical Discectomy and Fusion) for spondylotic radiculopathy and/or myelopathy. OUTCOME MEASURES: We analyzed fusion, disc height, cage or anchor micro plate migration, discal and segmental lordosis and subsidence. METHODS: All the patients were controlled at least one year after surgery with an average of 31 months. Antero-posterior and lateral X-rays were performed pre-operatively, immediate post-operatively, and at final follow up. The different radiographic measurements were performed with the assistance of software (SpineView®). CT-scans were performed for each case at final follow-up to assess the fusion. RESULTS: No migration or breakage was reported for either the cage or the anchor micro plate. The fusion rate was 94.1% at the final follow-up. No subsidence was observed. The disc height increased between preop and final follow-up from 23.3% to 44.3%, from 22.1% to 35.1% and from 38.3% to 51.5% for anterior, posterior and midline disc height respectively. Mean Functional Spinal Unit Lordosis increased from 0.9° preop to 3.0° at final follow-up. No new kyphotic situation could be noticed. At the final follow-up, 96% of the patients stated they would undergo the procedure again. CONCLUSION: With a high rate of proven fusion, restoration of disc height and spinal alignment in most cases, and absence of subsidence or migration, our radiological results with MC+® at more than 1 year of follow-up show the implanted device to be safe and effective for use in treating degenerative conditions of the cervical spine.

Trends in case-fatality rates in hospitalized nontraumatic subarachnoid hemorrhage: results of a population-based study in Dijon, France, from 1985 to 2006.

BACKGROUND: Subarachnoid hemorrhage accounts for 2% to 5% of all strokes and is associated with high morbidity and mortality rates. Reports in the literature show that case-fatality rates vary with time and according to geographical area. OBJECTIVE: The objective of the study was to evaluate the case-fatality rates in subarachnoid hemorrhage at 1 and 6 months and to determine trends in these rates over 22 years using a population-based registry. METHODS: The Dijon Stroke Registry has enabled us to perform a comprehensive analysis of subarachnoid hemorrhage diagnosed in a population of >150 000 inhabitants hospitalized between 1985 and 2006 in the Dijon University Hospital, which has both a neurosurgery unit and a neuroradiology unit. Diagnosis was based on clinical and neuroimaging features and, when necessary, on lumbar puncture. RESULTS: Case-fatality rates for hospitalized subarachnoid hemorrhages at 1 and 6 months were 15.59% (95% confidence interval [CI], 9.37-25.34) and 16.84% (95% CI, 10.33-26.78), respectively. From 1985 to 1995, case-fatality rates for SAH at 1 and 6 months were 17.1% (95% CI, 8.1-34.2) and 17.7% (95% CI, 9.6-31.3), whereas from 1996 to 2006, they were 20.2% (95% CI, 10.2-37.8) and 19.7% (95% CI, 11.1-33.6), respectively. CONCLUSION: Case-fatality rates for hospitalized subarachnoid hemorrhages in this population-based study remained stable over 22 years, suggesting that this stroke subtype is still a very severe disease despite early management. Most deaths occurred during the first 30 days. Further work is necessary to evaluate levels of prehospital case-fatality in our population-based registry.

Does core mobility of lumbar total disc arthroplasty influence sagittal and frontal intervertebral displacement? Radiologic comparison with fixed-core prosthesis.

BACKGROUND: An artificial disc prosthesis is thought to restore segmental motion in the lumbar spine. However, it is reported that disc prosthesis can increase the intervertebral translation (VT). The concept of the mobile-core prosthesis is to mimic the kinematic effects of the migration of the natural nucleus and therefore core mobility should minimize the VT. This study explored the hypothesis that core translation should influence VT and that a mobile core prosthesis may facilitate physiological motion. METHODS: Vertebral translation (measured with a new method presented here), core translation, range of motion (ROM), and distribution of flexion-extension were measured on flexion-extension, neutral standing, and lateral bending films in 89 patients (63 mobile-core [M]; 33 fixed-core [F]). RESULTS: At L4-5 levels the VT with M was lower than with F and similar to the VT of untreated levels. At L5-S1 levels the VT with M was lower than with F but was significantly different compared to untreated levels. At M levels a strong correlation was found between VT and core translation; the VT decreases as the core translation increases. At F levels the VT increases as the ROM increases. No significant difference was found between the ROM of untreated levels and levels implanted with either M or F. Regarding the mobility distribution with M and F we observed a deficit in extension at L5-S1 levels and a similar distribution at L4-5 levels compared to untreated levels. CONCLUSION: The intervertebral mobility was different between M and F. The M at L4-5 levels succeeded to replicate mobility similar to L4-5 untreated levels. The M at L5-S1 succeeded in ROM, but failed regarding VT and mobility distribution. Nevertheless M minimized VT at L5-S1 levels. The F increased VT at both L4-5 and L5-S1. CLINICAL RELEVANCE: This study validates the concept that the core translation of an artificial lumbar disc prosthesis minimizes the VT.