Efficacy of single antibiotic therapy versus antibiotic combination in implant-free staphylococcal post-surgical spinal infections: a retrospective observational study.

BACKGROUND: Post-surgical spinal infections (pSSIs) are a serious complication of spinal surgeries, with Staphylococcus spp. being one of the most prominent bacteria identified. Optimal antimicrobial therapy for staphylococcal spinal infections without spinal implants is not well documented. METHODS: This single center retrospective 7-year observational study described and compared the outcome (treatment failure or mortality rate one year after diagnosis) of 20 patients with staphylococcal-implant-free pSSI treated with single or combination antibiotics. RESULTS: Median duration of treatment was 40 days (IQR 38-42), with 6 days (IQR 5-7) on intravenous antibiotics and 34 days (IQR 30-36) on oral therapy. Four patients (20%) underwent new surgical debridement, all due to surgical failure, and 1 patient died within the first year without significant differences between both treatment group. CONCLUSION: This study raises the possibility of single antibiotic therapy for patients with implant-free post-surgical spinal infections due to Staphylococcus spp.

Influence of pelvic tilt correction on PJK occurrence after adult spinal deformity surgery.

INTRODUCTION: Many risk factors for proximal junctional kyphosis (PJK) have been reported in the literature, especially sagittal alignment modifications, but studies on pelvic tilt (PT) variations and its influence on PJK are missing. Aim of this study was to analyze the influence of pelvic tilt correction, after long fusion surgery for ASD patients, on PJK occurrence. METHODS: A monocentric retrospective study was conducted on prospectively collected data, including 76 patients, operated with fusion extending from the thoraco-lumbar junction to the ilium. Radiologic parameters were measured on fullspine standing radiographs preoperatively, postoperatively (<6 months) and at latest follow-up (before revision surgery or >2 years). All parameters were analyzed comparing patients with PJK (group "PJK") and without PJK (group "no PJK"). A further analysis compared patients with low (PT/PI<25th percentile, LowPT group) and high (PT/PI>75th percentile, HighPT group) preoperative pelvic tilt. RESULTS: « PJK ¼ patients had a greater lumbar lordosis and thoracic kyphosis correction (p=0,03 et <0,001 respectively) compared to the "no PJK" patients. Pelvic tilt was significantly lower postoperatively in the "PJK" group (p=0,03). Patients from the HighPT PJK group were significantly more corrected than patients from the HighPT noPJK group (p=0,003). CONCLUSION: Through the analysis of 76 patients, we showed that pelvic tilt did not seem to play a role in the setting of PJK after ASD surgery. Decreasing PT after surgery could be an element to watch out for in patients with PJK risk factors.

Optimization of radiation doses for open lumbar spinal fusion using C-arm fluoroscopy and impact on radiation-induced cancer: a pilot study.

PURPOSE: Intraoperative fluoroscopy use is essential during spinal fusion procedures. The amount of radiation dose should always be minimized. This study aimed to determine the feasibility of halving the frame rate from 12.5 to 6.25 frames per second (fps) and to quantify the reduction in the risk of developing radiation-induced cancer. METHODS: This pilot study included 34 consecutive patients operated for open lumbar posterolateral fusion (PLF) with or without transforaminal lumbar interbody fusion (TLIF). C-arm modes were changed from half-dose (12.5 frames per second (fps), group I) to quarter-dose (6.25 fps, group II). Age, body mass index, surgical procedure, number of treated levels, and complications were collected. Kerma area product (KAP), cumulative air kerma (CAK), and fluoroscopy time were compared. Effective dose and radiation-induced cancer risk were estimated. RESULTS: Eighteen and 16 patients were, respectively, included in group I and II. Demographic, surgical data, and fluoroscopy time were similar in both groups. However, CAK, KAP, and effective dose were significantly lower in group II, respectively, 0.56 versus 0.41 mGy (p = 0.03), 0.09 versus 0.06 Gy cm2 (p = 0.04), and 0.03 versus 0.02 mSv (p = 0.04). Radiation-induced cancer risk decreased by 47.7% from 1.49 × 10-6 to 7.77 × 10-7 after optimization. No complications were recorded in either group. CONCLUSION: This study demonstrates the feasibility of setting 6.25 fps for TLIF with and without PLF. By halving the fps, radiation-induced cancer risk could be almost divided by two, without compromising surgical outcome. Finally, after optimization, the risk of developing radiation-induced cancer was less than one in a million.

A comparison of idiopathic scoliosis surgery between teenage years and adulthood.

PURPOSE: Idiopathic scoliosis is an evolutive deformity during patient's life. In case of moderate deformity in a well aligned adolescent, it's a big concern to decide when to do the surgery. Objective of this work was to evaluate and compare clinical, radiological and surgical data of patients with adolescent idiopathic scoliosis operated in childhood (before 20 years) and those operated adults (after 35 years). METHODS: In this retrospective multicenter study, inclusion period extended from 2008 to 2018. Two groups were defined, those operated on before the age of 20 (YAIS), and those operated on after 35 years (OAIS). Demographic, radiographic and surgical data were collected. At follow-up, radiographic data and functional outcomes (VAS, SRS, SF12, Oswestry) were analyzed. Minimum FU was 5 years for young and 2 years for old patients. RESULTS: YAIS group included 364 patients, and OAIS group, 131 patients. In both groups, deformity was important (mean Cobb 63°). Vertebral osteotomies were significantly more frequent, fusions and length of stays were longer for old than young patients. Main Cobb correction was better in young than old (37 ± 10° vs 2 ± 13°, p = 0.03). Functional outcomes were better for young, operated patients than for operated groups after 35 years (SF12 PCS 50 ± 7 vs 39 ± 6, p = 0.02). The same trends were observed at longer follow-up. CONCLUSION: Surgery for idiopathic scoliosis seems to offer a better quality of life and deformity correction when it is performed at adolescence. After 35 years, surgery remains an acceptable therapeutic option, despite higher complication rate.

Sex-dependent evolution of whole-body postural alignment with age.

PURPOSE: The goal of this study was to explore sex-related variations of global alignment parameters and their distinct evolution patterns across age groups. METHODS: This multicentric retrospective study included healthy volunteers with full-body biplanar radiographs in free-standing position. All radiographic data were collected from 3D reconstructions: global and lower limb parameters, pelvic incidence (PI) and sacral slope (SS). Lumbar lordosis (LL), thoracic kyphosis (TK) and cervical lordosis (CL) were also assessed as well as the lumbar and thoracic apex, and thoracolumbar inflexion point. The population was divided into five 5 age groups: Children, Adolescents, Young, Middle-Aged and Seniors. RESULTS: This study included 861 subjects (53% females) with a mean age of 34 ± 17 years. Mean PI was 49.6 ± 11.1 and mean LL was - 57.1 ± 11.6°. Females demonstrated a PI increase between Young and Middle-Aged groups (49 ± 11° vs. 55 ± 12°, p < 0.001) while it remained stable in males. SS and LL increased with age in females while remaining constant in males between Children and Middle-aged and then significantly decreased for both sexes between Middle-Aged and Seniors. On average, lumbar apex, inflexion point, and thoracic apex were located one vertebra higher in females (p < 0.001). After skeletal maturity, males had greater TK than females (64 ± 11° vs. 60 ± 12°, p = 0.04), with significantly larger CL (-13 ± 10° vs. -8 ± 10°, p = 0.03). All global spinal parameters indicated more anterior alignment in males. CONCLUSION: Males present more anteriorly tilted spine with age mainly explained by a PI increase in females between Young and Middle-Aged, which may be attributed to childbirth. Consequently, SS and LL increased before decreasing at senior age.

Scoliosis.

Scoliosis is a three-dimensional spinal deformity that can occur at any age. It may be idiopathic or secondary in children, idiopathic and degenerative in adults. Management of patients with scoliosis is multidisciplinary, involving rheumatologists, radiologists, orthopaedic surgeons, and prosthetists. Imaging plays a central role in diagnosis, including the search for secondary causes, follow-up, and preoperative work-up if surgery is required. Evaluating scoliosis involves obtaining frontal and lateral full-spine radiographs in the standing position, with analysis of coronal and sagittal alignment. For adolescent idiopathic scoliosis, imaging follow-up is often required, accomplished using low-dose stereoradiography such as EOS imaging. For adult degenerative scoliosis, the crucial characteristic is rotatory subluxation, also well detected on radiographs. Magnetic resonance imaging is usually more informative than computed tomography for visualizing associated canal and foraminal stenoses. Radiologists must also have a thorough understanding of postoperative features and complications of scoliosis surgery because aspects can be misleading.

Pedagogy in spine surgery: developing a free and open-access virtual simulator for lumbar pedicle screws placement.

PURPOSE: Simulators for pedicle screws placement range from basic sawbones to virtual reality. Yet, they remain expensive and often require specific devices. No free online virtual simulator has yet been developed. The goal was to design a freely accessible Web-based simulator. METHODS: The computer simulator consisted of a lumbar spine, a red box hiding the pedicles and five pairs of screws. After inserting the screws, the red box was removed to assess their position. A validation study was conducted with 24 medical students randomized into a simulation and a control group. All had a basic course on pedicle screws. The 12 simulation group students performed two sessions on computer. All 24 students then conducted a final common step on sawbones. The number of misplaced screws, types of breaches, and simulation times were analyzed. RESULTS: In the final sawbones simulation, 96 real screws were studied. Control group misplaced 50% of their screws compared with only 20.8% in the simulation group (p < 0.05). More careful, simulation group students were slower to insert their real screws. Over the two computer simulations, the rate of misplaced screws decreased (12.5% vs. 38.3%), showing a good handling of the simulator. Students were able to analyze and correct their pedicle breaches. CONCLUSION: This tool is the first free online lumbar pedicle screws simulator. Simulation helped students to better position the final real screws on sawbones. This project showed it was possible to create a free educational tool with no special equipment. LEVEL OF EVIDENCE: Level 3.

Femoral neck version in the spinopelvic and lower limb 3D alignment: a full-body EOS® study in 400 healthy subjects.

BACKGROUND: The goal of this study was to better understand the variation of femoral neck version according to spinopelvic and lower limb 3D alignment using biplanar X-rays in standing position. METHODS: This multicentric study retrospectively included healthy subjects from previous studies who had free-standing position biplanar radiographs. Subjects were excluded if they presented spinal or any musculo-skeletal deformity, and reported pain in the spine, hip or knee. Age, sex, and the following 3D-reconstructed parameters were collected: spinal curvatures, pelvic parameters, sagittal vertical axis (SVA), T1 pelvic angle (TPA), spino-sacral angle (SSA), femoral torsion angle (FTA), sacro-femoral angle (SFA), knee flexion angle (KA), ankle angle (AA), pelvic shift (PS) and ankle distance. Femoral neck version angle (FVA) was calculated between horizontal plane projection of the bi-coxo-femoral axis and the line passing through the femoral neck barycenter and femoral head center. Analysis according to age subsets was performed. RESULTS: A total of 400 subjects were included (219 females); mean age was 29 ± 18 years (range: 4-83). Subjects with high pelvic tilt values presented significantly higher FVA than average and low-PT individuals, respectively, 7.8 ± 7.1°, 2 ± 9° and 2.1 ± 9.5° (p < 0.001). These subjects also presented lower lumbar lordosis values and higher acetabulum anteversion in the horizontal plane than the two other groups. SVA correlation with FVA was weaker (r = 0.1, p = 0.03) than SSA and TPA (r = - 0.3 and r = 0.3, respectively, p < 0.001). A strong correlation was found with femoral torsion (r = 0.5, p < 0.001). SFA (r = - 0.3, p < 0.001), pelvic shift (r = 0.2, p < 0.001) and ankle distance (r = 0.3, p < 0.001) were also significantly correlated. Multivariate analysis confirmed significant association of age, pelvic tilt, lumbar lordosis, pelvic shift, ankle distance and femoral torsion with FVA. CONCLUSION: Patients with lower lumbar lordosis present pelvic retroversion which induces a higher femoral neck version. This finding may help positioning implants in total hip replacement procedures. Higher pelvic shift, age, male gender and increased femoral torsion were also correlated with higher FVA. LEVEL OF EVIDENCE: II (Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding).

Sagittal correction after short percutaneous fixation for thoracolumbar compression fractures: comparison of the combination of SpineJack® kyphoplasty and fractured vertebra screw fixation.

PURPOSE: The aim of this study was to compare two percutaneous pedicle fixations for the treatment of thoracolumbar fractures: one associating a jack kyphoplasty (SpineCut) and the other using intermediate screws (Trident). METHODS: All adult patients treated for single-level Magerl/AO type A thoracolumbar traumatic fractures in four orthopaedic departments, with SpineCut or Trident, with a one year minimum follow-up, were retrospectively included. Neurological disorders and osteoporotic fractures were not included. The following data were collected: age, sex, Magerl/AO type, type of surgery, and complications. Radiological parameters were analyzed on pre-operative CT scan, and on standing X-rays before discharge, at three months and one year post-operative: vertebral wedge angle (VWA), regional kyphosis angle (RKA), and traumatic regional angulation (TRA: difference between RKA and physiological values for each vertebra). RESULTS: Eighty patients were included, with 42 patients in SpineCut group and 38 in Trident group. Mean age was 41 ± 15.7 years. TRA correction did not differ between the groups: respectively 11.2 ± 8.1° in SpineCut versus 10.2 ± 9.1° in Trident group (p = 0.52). TRA loss of correction between early post-operative and three months was statistically higher in Trident group: -4 ± 5.1° versus -1.5 ± 3.8° (p = 0.03). After 3 months, TRA correction loss was comparable between the groups. Multivariate analysis demonstrated that pre-operative VWA was the only factor significantly associated with early TRA correction loss (p = 0.01). VWA correction and loss of correction did not differ significantly between the groups. No complications were observed. CONCLUSION: Percutaneous pedicle fixations of traumatic thoracolumbar fractures associating jack kyphoplasty and intermediate screws are both safe and efficient techniques.

Implant removal after short percutaneous pedicle fixation associated with SpineJack® kyphoplasty: is correction sustained?

PURPOSE: This study objective was to evaluate sagittal correction loss after instrumentation removal in patients treated for thoracic or lumbar compression fractures treated with SpineJack® kyphoplasty associated with short percutaneous pedicle screw fixation. METHODS: This retrospective multicenter study was carried out in three major French trauma centers. All patients with a single type A thoracic or lumbar fracture, treated by the studied technique between 2017 and 2020, have been included. Demographic data, fracture type, removal procedure achievement and term were collected. Radiological parameters were measured at five timepoints: pre-operative, intra-operative, immediate post-operative, early post-operative (< 3 months) and at follow-up (1 year). Vertebral wedge angle (angle between the two endplates of the fractured vertebra) and traumatic regional angulation (TRA-calculated by subtracting regional kyphosis from the physiological reference values). RESULTS: 150 patients were included. Mean age was 48.6 ± 17.8 years. Average follow-up was 14.4 ± 3 months. 82 patients had secondary instrumentation removal. Mean time to removal was 6.4 ± 2.4 months. TRA correction loss between immediate post-operative and last follow-up was greater in removal group: 5.1 ± 5.6° versus 2.7 ± 4.7° (p = 0.01). Material was removed earlier in younger patients (p = 0.002). TRA correction loss was similar in the early and late removal groups (p = 0.83). Multivariate analysis identified only Magerl/AO A3 fractures as risk factor for loss of TRA correction (p = 0.007). CONCLUSION: Instrumentation removal was associated with good radiological outcomes with a non-significant loss of vertebral wedge angle and tolerable loss of traumatic regional angulation (+ 2.4° compared to the no-removal group), even if performed early.

The rib cage: a new element in the spinopelvic chain.

INTRODUCTION: This study analyzes anatomical variations of the thoracic cage (TC) according to spinopelvic alignment, age and gender using stereoradiography in erect position. METHODS: This retrospective multicentric study analyzed computed parameters collected from free-standing position bi-planar radiographs, among healthy subjects. Collected data were: age, gender, pelvic parameters (Pelvic Incidence, Pelvic Tilt (PT) and Sacral Slope), T1-T12 Kyphosis (TK), L1-S1 Lordosis (LL), curvilinear spinal length, global TC parameters (maximum thickness and width, rib cage volume, mean Spinal Penetration Index (SPI)), 1st-10th rib parameters (absolute and relative (to the corresponding vertebra) sagittal angles). RESULTS: Totally, 256 subjects were included (140 females). Mean age was 34 (range: 8-83). Significant correlations were found between TK and TC thickness (0.3, p < 0.001) and with TC Volume (0.3, p = 0.04), as well as rib absolute sagittal angle for upper and middle ribs (0.2, p = 0.02). Conversely, a -0.3 correlation has been exhibited between SPI and TK. Similar correlations were found with LL. PT significantly correlated with TC thickness (0.4, p = 0.003), SPI (-0.3, p = 0.03), and all rib relative sagittal angles. Among global TC parameters, only thickness and SPI significantly changed after 20 years (respectively, 0.39 and -0.52, p < 0.001). Ribs relative sagittal angle showed negative correlation with age in skeletally mature subjects (p < 0.001). CONCLUSION: This study demonstrates the correlation between TC anatomy and spinopelvic parameters, confirming its part of the spinopelvic chain of balance. Indeed, higher spinal curvatures were associated with lower SPI and higher TC thickness, TC volume and rib absolute sagittal angles.

Efficiency of a novel vertebral body augmentation system (Tektona™) in non-osteoporotic spinal fractures.

BACKGROUND: The restauration of the local kyphosis is crucial to thoracolumbar fractures outcomes. Recently, the Tektona™ (Spine Art) system, constituted by a flexible lamella for corporeal reduction has emerged as a promising solution for osteoporotic fractures. However, no study has yet focused on its results on traumatic fractures. METHODS: A retrospective longitudinal study on prospectively collected data was conducted on 53 patients that had a kyphoplasty by Tektona™, associated or not to percutaneous fixation. The data collected were clinical, surgical and scannographic (measurement of AVH, MVH and PVH (anterior/medium/posterior vertebral height), and RTA (regional traumatic angle) in°), preoperatively, post-operatively and at last follow-up. RESULTS: Fractures were mainly located at the upper lumbar spine and were AOSpine A3 type for 74%. The mean RTA was 12° in pre-operative, 4° in post-operative (p = 2e- 9), and 8° at the last follow-up (p = 0,01). The mean correction of RTA for the fixation group was - 10 ± 6° versus - 7 ± 4° for the kyphobroplasty alone group (p = 0,006). The mean correction for fractures located at T10-T12 was - 9 ± 3°, - 9 ± 5° for L1, - 8 ± 3° for L2 and - 5 ± 3° for L3-L5 (p = 0,045). CONCLUSIONS: The Tektona® system appears to be efficient for acute thoraco-lumbar fractures, comparable to other available systems, allowing a real intracorporeal reduction work. Its relevance, especially in the long term needs further investigation. The association of a percutaneous fixation allow to obtain a better correction of the RTA but did not seem to prevent the loss of correction at follow-up.

Global alignment taking into account the cervical spine with odontoid hip axis angle (OD-HA).

INTRODUCTION: Global alignment analysis is of upmost importance in adult spinal deformity patients (ASD). Numerous parameters exist in the literature to measure global alignment based upon C7 or T1. One common limitation of these parameters is that they neglect the cervical segment which is essential in spinal compensatory mechanisms and in horizontal gaze preservation. A recent stereoradiography analysis of asymptomatic subjects introduced a new 3D parameter (ODHA), defined as the angle between the vertical reference line and the line joining the odontoid tip (OD) to hip axis center (HA). Thus, the goal of this study was to analyze 3D global alignment of ASD patients using the new parameter odontoid hip axis angle and its relationship to other spinal parameters. METHODS: In this prospective study, 90 adult patients with lumbar scoliosis (Cobb > 20°) were included. All subjects underwent low dose biplanar X-rays with 3D spinal reconstructions. Based on published normative values of ODHA, we defined abnormally high value as mean ODHA of asymptomatic subject + 2SD (i.e., ODHA > 6.1°). Values of 3D radiographic parameters and ODI were compared between patients with ODHA > 6.1° and < 6.1°. RESULTS: Mean ODHA was 5+/- 3.6° (0.4° to 18.6°). 22 patients had abnormally high ODHA. They were older than the 68 other patients (68+/- 9y vs 53+/- 14y, p = 0.001), without any significant difference in terms of sex, BMI and rate of rotatory subluxation (54% vs 62%, p = 0.06). However, coronal and sagittal deformity was more important in patients with abnormal ODHA (larger Cobb angle, coronal malalignment, pelvic tilt and lower lumbar lordosis). Patients with abnormal ODHA had significantly worst ODI (50+/- 23 vs 30+/- 18, p = 0.0005). CONCLUSION: Extreme values of ODHA are observed in significantly older patients with significant functional impairment. In addition, in these patients with sagittal malalignment with loss of lumbar lordosis, who recruit compensatory mechanisms such as pelvic retroversion, the cervical area is also involved with a posture in cervical hyperlordosis to maintain the head over the pelvis. Thus, ODHA is an interesting parameter allowing a more comprehensive alignment measurement taking into account the mechanisms of compensation of the cervical spine to the pelvis.

Dynesys® dynamic stabilization outcomes in degenerative spine surgery.

Dynesys® is a dynamic device used for posterior stabilization of the lumbar spine. The objective of this study was to analyze the clinical and radiological outcomes at a 2-year minimum follow-up. In this retrospective study, patients operated between 2009 and 2016 with Dynesys® stabilization were included. 5 different etiologies were included: disc herniation, lumbar stenosis, revision for adjacent seg- ment disease (ASD), spondylolisthesis, and scoliosis. Clinical and radiological evaluations were performed. Postoperative complications and revisions were recorded. 136 patients were included: 34 for lumbar spinal stenosis, 19 for disc herniation, 29 degenerative spon- dylolisthesis, 41 revisions for ASD, and 13 scoliosis. Mean age was 64.8. Average clinical follow-up was 46 months. Postoperative clinical results showed a mean lumbar VAS of 3.07, a mean radicular VAS of 3.01 and an ODI score of 31.8%. The ASD rate was 16.2%, and overall revision rate was 11.8%. 2 cases (1.5%) of screw loosening were identified. Clinical outcomes, ASD rate and revision rate were more favorable in the spondylolisthesis and disc herniation groups. This study has one of the largest Dynesys® cohort in literature. Spinal dynamic stabilization by Dynesys® presents good long-term clinical and radiological out- comes with a lower rate of complications than pre- viously published cohorts and lumbar fusions. Best indications seem to be degenerative spondylolisthesis.

Relationships between radiographic parameters and spinopelvic muscles in adult spinal deformity patients.

INTRODUCTION: While the clinical impact of coronal and sagittal alignment in adult spinal deformity (ASD) patients (pts) is established, there is a paucity of data in terms of axial plane deformity and potential association between muscle degeneration and 3D deformity. The purpose of this study was to analyze spinopelvic muscles characteristics in association with the 3D deformity of ASD patients. METHODS: This is a prospective cohort study; primary lumbar scoliosis patients (Cobb > 20°) were enrolled and sustained a low-dose X-rays with 3D spinal reconstructions and a fat/water separation MRI (from C7 to the knee). Volumetric 3D reconstructions and fat infiltration (FI) of 6 muscles groups were performed. Relationships between muscular data, radiographic parameters and health-related quality of life were investigated. Patients were stratified and compared based on the SRS classification, the odontoid-hip axis (ODHA) angle (> or < 6.1°) and occurrence of rotatory subluxation. RESULTS AND DISCUSSION: Twenty-eight patients were enrolled with a mean age of 60 ± 16yo and mean body mass index of 26 ± 4 kg/m2 without differences between groups. There were a moderate sagittal malalignment and a Cobb angle of 45 ± 11° (table). Muscular volume was smaller in patients with more severe deformity (p > 0.05). Pts with ODHA > 6.1° or pelvic incidence minus lumbar lordosis > 10° had significantly higher FI for the 6 muscular groups, patients with pelvic tilt > 20° had significantly higher FI for erector spinae, hip flexors and extensors (p < 0.05). SF36-PCS significantly correlated with the muscular volume; SRS and Oswestry disability index correlated with the erectors spinae volume (p < 0.05). CONCLUSION: This study analyzed for the first time the relationship between 3D radiographic parameters and muscular characteristics in ASD. Sagittal malalignment is associated with increased FI and decreased muscle volumes with poor outcomes. These slides can be retrieved under Electronic Supplementary Material.

Full-body Postural Alignment Analysis Through Barycentremetry.

STUDY DESIGN: Multicentric retrospective. OBJECTIVE: The study of center of mass (COM) locations (i.e. barycentremetry) can help us understand postural alignment. This study goal was to determine relationships between COM locations and global postural alignment X-ray parameters in healthy subjects. The second objective was to determine the impact on spinopelvic alignment of increased distance between anterior body envelope and spine at lumbar apex level. SUMMARY OF BACKGROUND DATA: Unexplored relationship between COM location and spinopelvic parameters. METHODS: This study included healthy volunteers with full-body biplanar radiograph including body envelope reconstruction, allowing the estimation of COM location. The following parameters were analyzed: lumbar lordosis (LL), thoracic kyphosis (TK), cervical lordosis (CL), pelvic tilt (PT), Sacro-femoral angle (SFA), Knee flexion angle (KFA), sagittal odontoid-hip axis angle (ODHA). The following COM in the sagittal plane were located: whole body, at thoracolumbar inflexion point, and body segment above TK apex. The body envelope reconstruction also provided the distance between anterior skin and the LL apex vertebral body center ("SV-L distance"). RESULTS: This study included 124 volunteers, with a mean age of 44±19.3. Multivariate analysis confirmed posterior translation of COM above TK apex with increasing LL (P=0.002) through its proximal component, and posterior shift of COM at inflexion point with increasing TK (P=0.008). Increased SV-L distance was associated with greater ODHA (r=0.4) and more anterior body COM (r=0.8), caused by increased TK (r=0.2) and decreased proximal and distal LL (both r=0.3), resulting in an augmentation in SFA (r=0.3) (all P<0.01). CONCLUSIONS: Barycentremetry showed that greater LL was associated with posterior shift of COM above thoracic apex while greater TK was correlated with more posterior COM at inflexion point. Whole-body COM was strongly correlated with ODHA. This study also exhibited significant alignment disruption associated with increased abdominal volume, with compensatory hip extension. LEVEL OF EVIDENCE: II.

Does Spinal Surgery in Elderly Patients (Over 80 Years-Old) Lead to More Early Post-Operative Complications Than Lower Limb Prosthetic Surgery?

Purpose: Patients and surgeons may be reluctant on spinal surgery over 80 years old, fearing medical complications despite the possible improvement on quality of life. However, fewer reservations for lower limb prosthetic surgery (LLPS) seem to be arisen in this population. Is spinal surgery after 80 years-old responsible of more complications than lower limb surgery? Methods: The consecutive files of 164 patients over 80 years that had spinal surgery or LLPS were analyzed. The data collected pre-operatively were demographic, clinical and post-operatively the number and types of medical complications and length of stay. Results: The mean number of medical complications was 1.11 ± 0.6 [0-6] for spinal surgery and 1.09 ± 1.0 [0-3] for LLPS, (p = 0,87). The length of stay in orthopedic unit was comparable between the two groups: 10.7 ± 4.9 days [2-36] for SS and 10.7 ± 3.0 days [5-11] for LLPS (p = 0,96). Conclusion: The global rate of peri-operative complications and the length of hospital stay were similar between spinal surgery and lower limb prosthetic surgery. These results may be explained by the rising cooperation between geriatric specialist and surgeons and the development of mini-invasive surgical technics, diminishing the early post-operative complication rates.

Revision Strategy for Proximal Junctional Failure: Combined Effect of Proximal Extension and Focal Correction.

STUDY DESIGN: Retrospective review of a prospectively-collected multicenter database. OBJECTIVES: The objective of this study was to determine optimal strategies in terms of focal angular correction and length of proximal extension during revision for PJF. METHODS: 134 patients requiring proximal extension for PJF were analyzed in this study. The correlation between amount of proximal junctional angle (PJA) reduction and recurrence of proximal junctional kyphosis (PJK) and/or PJF was investigated. Following stratification by the degree of PJK correction and the numbers of levels extended proximally, rates of radiographic PJK (PJA >28° & ΔPJA >22°), and recurrent surgery for PJF were reported. RESULTS: Before revision, mean PJA was 27.6° ± 14.6°. Mean number of levels extended was 6.0 ± 3.3. Average PJA reduction was 18.8° ± 18.9°. A correlation between the degree of PJA reduction and rate of recurrent PJK was observed (r = -.222). Recurrent radiographic PJK (0%) and clinical PJF (4.5%) were rare in patients undergoing extension ≥8 levels, regardless of angular correction. Patients with small reductions (<5°) and small extensions (<4 levels) experienced moderate rates of recurrent PJK (19.1%) and PJF (9.5%). Patients with large reductions (>30°) and extensions <8 levels had the highest rate of recurrent PJK (31.8%) and PJF (16.0%). CONCLUSION: While the degree of focal PJK correction must be determined by the treating surgeon based upon clinical goals, recurrent PJK may be minimized by limiting reduction to <30°. If larger PJA correction is required, more extensive proximal fusion constructs may mitigate recurrent PJK/PJF rates.

Pre- and postoperative MRI analysis of central decompression in MIS fusion with lumbar stenosis.

OBJECTIVES: Mini-invasive approaches have grown substantially these last decades in spinal surgery, notably for lumbar decompressions and fusion, with advantages over open approaches in terms of morbidity reduction. However, to our knowledge, no study has measured on MRI the amount of central decompression obtained by MIS approach. The goal of this study was to precisely measure the decompression of central stenosis by unilateral MIS approaches. METHODS: The files of 42 patients that had a MIS lumbar fusion with central decompression for central stenosis were reviewed. All patients had a pre- and postoperative MRI that allowed on T2 axial images to classify the central stenosis, according to Schizas' classification, and measure the dural sac cross-sectional area (DSCA) and the anteroposterior diameter (DAP). The statistical analysis was made with paired t-test. RESULTS: Fifty-six levels were analyzed, mostly L4L5 (58%). The mean preoperative DSCA was 70.53mm2 and the mean postoperative DSCA was 172.2mm2. The mean preoperative DAP was 6.15mm and postoperative was 10.68mm. Preoperatively, the levels analyzed were rated B, C or D according to Schizas for 53 out of 56 levels and A1-4 for 51 out of 56 levels in postoperative. All the results were statistically significant (p<0.001). CONCLUSION: Decompression, assessed by MRI, seems to be equivalent by MIS approach to open laminarthrectomy. MIS approaches have been studied clinically in these indications with very satisfying results. As a conclusion, MIS approaches seems to be a relevant and efficient option in the treatment of lumbar degenerative stenosis. LEVEL OF EVIDENCE: IV, retrospective study.

Surgical treatment of degenerative lumbar spondylolisthesis: Effect of TLIF and slip reduction on sagittal alignment.

INTRODUCTION: The surgical treatment of lumbar degenerative spondylolisthesis (LDS) remains controversial. The aim of this study was to determine the effect of adding transforaminal lumbar interbody fusion (TLIF) to posterolateral fusion (PLF) on the local lordosis, sagittal alignment and potential complications. The second aim was to evaluate the effect of slip reduction on the same parameters. HYPOTHESIS: The initial hypothesis was that TLIF provides better correction of the local lordosis and that reducing the slip improves the global sagittal balance. METHODS: In this retrospective, single-center study, patients who had been operated on for LSD at one or two levels by laminectomy and PLF, with or without a TLIF cage, were included. Data collected consisted of age, sex, number of levels fused and whether or not a TLIF cage was used. Fusion was defined as the absence of indirect nonunion signs on radiographs at 2 years postoperative. The occurrence and time frame of any complications and the need for reoperation were documented. Lateral radiographs of the entire spine were analyzed preoperatively, in the early postoperative period (3 to 6 months) and at a minimum follow-up of 2 years. The following parameters were measured: pelvic parameters, C7 sagittal tilt (C7ST), spinosacral angle (SSA), maximum lumbar lordosis (LL), lordosis at slipped level (LS), slip percentage. The analysis compared patients treated by PLF and TLIF and determined the impact of slip reduction. RESULTS: One hundred and three patients were included in the study (71% women). The mean follow-up was 38 months. The mean age was 69 years. Seventy-seven patients (75%) underwent PLF. Comparing the preoperative and early postoperative data identified 5.4% better spondylolisthesis reduction in the TLIF group than the PLF group (-8.9±9.5% vs -3.5±7.6%; p=0.04) that was not maintained at the final follow-up. The fusion rate was comparable between groups: 94% in APL and 89% in TLIF (p=0.7). The overall complication rate was 46% in the TLIF group versus 33% in the PLF group (p=0.35). A comparison based on whether or not the slip was reduced found significant improvement in the reduction group of the SSA by more than 6° (6.8°±6° vs 0.5°±7.4°; p=0.04). The fusion rate was 91% in the reduced group and 95% in the non-reduced group (p=0.81); the complication rate was 44% versus 28% in the non-reduced group (p=0.10). CONCLUSION: This study shows that slip reduction helps to improve the sagittal alignment by increasing the SSA when treating LDS. Posterolateral fusion and TLIF produce comparable radiographic outcomes at 2 years postoperative in the segmental lordosis, slip reduction, global sagittal alignment and fusion rate. LEVEL OF EVIDENCE: IV.