Clinical effectiveness of reduction and fusion versus in situ fusion in the management of degenerative lumbar spondylolisthesis: a systematic review and meta-analysis.

PURPOSE: To compare the clinical effectiveness of reduction and fusion with in situ fusion in the management of patients with degenerative lumbar spondylolisthesis (DLS). METHODS: The systematic review was conducted following the PRISMA guidelines. Relevant studies were identified from PubMed, Embase, Scopus, Cochrane Library, ClinicalTrials.gov, and Google Scholar. The inclusion criteria were: (1) comparative studies of reduction and fusion versus in situ fusion for DLS patients, (2) outcomes reported as VAS/NRS, ODI, JOA score, operating time, blood loss, complication rate, fusion rate, or reoperation rate, (3) randomized controlled trials and observational studies published in English from the inception of the databases to January 2023. The exclusion criteria included: (1) reviews, case series, case reports, letters, and conference reports, (2) in vitro biomechanical studies and computational modeling studies, (3) no report on study outcomes. The risk of bias 2 (RoB2) tool and the Newcastle-Ottawa scale was conducted to assess the risk of bias of RCTs and observational studies, respectively. RESULTS: Five studies with a total of 704 patients were included (375 reduction and fusion, 329 in situ fusion). Operating time was significantly longer in the reduction and fusion group compared to in situ fusion group (weighted mean difference 7.20; 95% confidence interval 0.19, 14.21; P = 0.04). No additional significant intergroup differences were noted in terms of other outcomes analyzed. CONCLUSION: While the reduction and fusion group demonstrated a statistically longer operating time compared to the in situ fusion group, the clinical significance of this difference was minimal. The findings suggest no substantial superiority of lumbar fusion with reduction over without reduction for the management of DLS.

Acute Cervical Radiculopathy Outcomes: Soft Disc Herniations vs Osteophytes.

OBJECTIVE: Prospectively evaluate the clinical outcomes of acute cervical radiculopathy with respect to soft disc herniations vs osteophytes. METHODS: Sixty consecutive patients who had had cervical radiculopathy for ≤1 month were enrolled in the study. Inclusion criteria were radicular pain greater than axial pain and a pain score ≥4 out of 10 on a numerical rating scale. Patients had at least one positive clinical finding: motor, sensory, or reflex changes. Plain films and magnetic resonance imaging were ordered. Follow-up was at 6 weeks and 3, 6, and 12 months. Outcomes included pain scores (neck and upper limb), neck disability index, medication use, opioid use, and need for surgery. Two attending musculoskeletal radiologists reviewed imaging findings for osteophytes vs soft disc herniations at the symptomatic level. RESULTS: More than 75% reduction in pain was seen in 77% of patients with soft disc herniations and 66% of patients with osteophytes (P > 0.05) at 12 months. A pain score ≤2 out of 10 within 6 to 12 months was seen in 86% of patients with soft disc herniations and 81% of patients with osteophytes (P > 0.05). Moderate or marked improvement at 12 months was seen in 85% of patients with soft discs and 77% of patients with osteophytes (P > 0.05). Baseline-to-12-month numerical rating scale pain scores of patients with soft discs vs osteophytes had overlapping confidence intervals at each follow-up. At 12 months, very few had undergone surgery (7% of patients with soft discs, 11% of patients with osteophytes; P > 0.05) or were on opioids (7% of patients with soft discs, 9% of patients with osteophytes; P > 0.05). CONCLUSIONS: The majority of patients, but not all patients, with acute radiculopathies improved with time. This was seen with both soft disc herniations and osteophytes.

The effect of capacitively coupled (CC) electrical stimulation on human disc nucleus pulposus cells and the relationship between CC and BMP-7.

PURPOSE: An in vitro study using human intervertebral disc nucleus pulposus cells to evaluate the effects of CC stimulation on disc-matrix macromolecule production. METHODS: Nucleus pulposus cells were cultured in alginate beads and treated with CC stimulation. The effect of BMP on CC stimulation of the cells was evaluated by applying a BMP blocker (noggin) or by applying additional BMP-7 to the culture. The mRNA levels of the disc extracellular matrix genes (collagen I, II, aggrecan) and BMPs were measured by real-time PCR. The protein levels of aggrecan, collagen II, and BMPs were determined by ELISAs and Western blots. Sulfated glycosaminoglycan (sGAG) content was assayed using the DMMB method. RESULTS: (1) CC stimulation upregulates the production of the disc-matrix macromolecular components: sGAG, aggrecan and collagen II; (2) CC stimulation increases the ratio of mRNA expression levels of collagen II to collagen I; (3) CC stimulation induces the expression of endogenous BMP-4 and BMP-7; (4) inhibition of BMP activity (using noggin) reduces CC-mediated upregulation of aggrecan and collagen II; (5) CC and BMP-7 act in synergy to increase the upregulation of disc-matrix macromolecules. CONCLUSION: CC stimulation upregulates the production of the intervertebral disc-matrix macromolecules aggrecan, collagen II, and sGAG by a mechanism involving BMPs. CC stimulation acts in synergy with BMP-7 to increase the upregulation of these disc-matrix macromolecules.

The effect of hubbing on the pull-out strength of lateral mass screws in the cervical spine: a biomechanical experiment.

STUDY DESIGN: This was a cadaveric biomechanical experiment. OBJECTIVE: To compare the pull-out strength of polyaxial screws that are either hubbed or not hubbed when inserted into the lateral mass. SUMMARY OF BACKGROUND DATA: It has been shown in a study on pedicle screws in the thoracic spine that "hubbing" the head of the screw against the dorsal laminar cortex results in significantly lower pull-out strength of the screws. MATERIALS AND METHODS: Fifteen segments of the human cervical spine (from C3 to C7) were prepared. Polyaxial screws 3.5 mm in diameter were used. On one side screws 12 mm in length were inserted until the screw head touched the lateral mass; they were then turned 2.5 more times until they were fully hubbed (hubbed screws). On the other side screws 14 mm in length were inserted until the screw head just touched the lateral mass (nonhubbed screws). The 2 mm difference in length was to ensure that the screws were buried to the same length. All screws inserted into the lateral masses underwent tensile pull-out by applying a tensile force down the long axis of the screw. The difference in pull-out strength between the 2 groups was evaluated using a nonparametric paired test (the Wilcoxon signed rank test), which compared side to side on each vertebra. RESULTS: One specimen was excluded because of cement breakage during the biomechanical test. A total of 14 vertebrae were tested. Four vertebrae in the hubbed group showed small fractures or cracks around the screw hole after screw insertion. In a side to side comparison, the hubbed screws had significantly lower pull-out strengths as compared with the nonhubbed screws (P=0.033). CONCLUSIONS: Hubbing of lateral mass screws lowers the potential pull-out strength of the screws as compared with the pull-out strength of nonhubbed screws. Thus, hubbing of lateral mass screws, on the basis of the parameters applied in this study, is not recommended.

Link protein N-terminal peptide binds to bone morphogenetic protein (BMP) type II receptor and drives matrix protein expression in rabbit intervertebral disc cells.

Intervertebral disc (IVD) degeneration and associated spinal disorders are leading sources of morbidity, and they can be responsible for chronic low back pain. Treatments for degenerative disc diseases continue to be a challenge. Intensive research is now focusing on promoting regeneration of degenerated discs by stimulating production of the disc matrix. Link protein N-terminal peptide (LPP) is a proteolytic fragment of link protein, an important cross-linker and stabilizer of the major structural components of cartilage, aggrecan and hyaluronan. In this study we investigated LPP action in rabbit primary intervertebral disc cells cultured ex vivo in a three-dimensional alginate matrix. Our data reveal that LPP promotes disc matrix production, which was evidenced by increased expression of the chondrocyte-specific transcription factor SOX9 and the extracellular matrix macromolecules aggrecan and collagen II. Using colocalization and pulldown studies we further document a noggin-insensitive direct peptide-protein association between LPP and BMP-RII. This association mediated Smad signaling that converges on BMP genes leading to expression of BMP-4 and BMP-7. Furthermore, through a cell-autonomous loop BMP-4 and BMP-7 intensified Smad1/5 signaling though a feedforward circuit involving BMP-RI, ultimately promoting expression of SOX9 and downstream aggrecan and collagen II genes. Our data define a complex regulatory signaling cascade initiated by LPP and suggest that LPP may be a useful therapeutic substitute for direct BMP administration to treat IVD degeneration and to ameliorate IVD-associated chronic low back pain.

The Role of Osteobiologics in Augmenting Spine Fusion in Unplated Anterior Cervical Discectomy and Fusion Compared to Plated Constructs: A Systematic Review and Meta-analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: To compare clinical and radiographic outcomes as well as complications of unplated vs plated anterior cervical discectomy and fusion (ACDF) surgery considering the role of osteobiologics in single- and multi-level procedures. METHODS: A systematic search of PubMed/MEDLINE, Scopus, CINAHL, EMBASE, CENTRAL, Cochrane and ClinicalTrials.gov databases was performed. Briefly, we sought to identify studies comparing unplated vs. plated ACDF for cervical degenerative disc disease reporting the use of osteobiologics in terms of clinical outcomes, radiographic fusion, and complications. Data on study population, follow-up time, type of cage and plate used, type of osteobiologic employed, number of levels treated, patient-reported outcomes (PROs), radiographic outcomes and complications were collected and compared. Relevant information was pooled for meta-analyses. RESULTS: Thirty-eight studies met the inclusion criteria. No significant difference was found in terms of clinical outcomes between groups. Unplated ACDF was characterized by reduced blood loss, operation time and length of hospital stay. Fusion was achieved by the majority of patients in both groups, with no evidence of any specific contribution depending on the osteobiologics used. Dysphagia was more commonly associated with anterior plating, while cage subsidence prevailed in the unplated group. CONCLUSION: Unplated and plated ACDF seem to provide similar outcomes irrespective of the osteobiologic used, with minor differences with doubtful clinical significance. However, the heterogeneity and high risk of bias affecting included studies markedly prevent significant conclusions.

Structural Allograft Versus Mechanical Interbody Devices Augmented With Osteobiologics in Anterior Cervical Discectomy and Fusion: A Systematic Review.

STUDY DESIGN: Systematic Literature Review. OBJECTIVE: Perform a systematic review evaluating postoperative fusion rates for anterior cervical discectomy and fusion (ACDF) using structural allograft vs various interbody devices augmented with different osteobiologic materials. METHODS: Comprehensive literature search using PubMed, Embase, The Cochrane Library, and Web of Science was performed. Included studies were those that reported results of 1-4 levels ACDF using pure structural allograft compared with a mechanical interbody device augmented with an osteobiologic. Excluded studies were those that reported on ACDF with cervical corpectomy; anterior and posterior cervical fusions; circumferential (360° or 540°) fusion or revision ACDF for nonunion or other conditions. Risk of bias was determined using the Cochrane review guidelines. RESULTS: 8 articles reporting fusion rates of structural allograft and an interbody device/osteobiologic pair were included. All included studies compared fusion rates following ACDF among structural allograft vs non-allograft interbody device/osteobiologic pairs. Fusion rates were reported between 84% and 100% for structural allograft, while fusion rates for various interbody device/osteobiologic combinations ranged from 26% to 100%. Among non-allograft cage groups fusion rates varied from 73-100%. One study found PEEK cages filled with combinations of autograft, allograft, and demineralized bone matrix (DBM) to have an overall fusion rate of 26%. In one study comparing plate and zero-profile constructs, there was no difference in fusion rates for two-level fusions. CONCLUSION: There was limited data comparing fusion outcomes of patients undergoing ACDF using structural allograft vs interbody devices augmented with osteobiologic materials to support superiority of one method.

Radiographic Risk Factors for Adjacent Segment Disease Following Anterior Cervical Discectomy and Fusion (ACDF): A Systematic Review and Meta-Analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVES: To assess the radiographic risk factors for adjacent segment disease (ASD) following anterior cervical discectomy and fusion (ACDF) for degenerative cervical spine pathologies. METHODS: PubMed, Embase and the Cochrane Library databases were searched up to December 2023. The primary inclusion criteria were degenerative spinal conditions treated with ACDF, comparing radiological parameters in patients with and without postoperative ASD. The radiographic parameters included intervertebral disc height, cervical sagittal alignment, sagittal segmental alignment, range of motion, segmental height, T1 slope, sagittal vertical axis (SVA), thoracic inlet angle (TIA), and plate to disc distance (PPD). Risk of bias was assessed for all studies. The Cochrane Review Manager was utilized to perform the meta-analysis. RESULTS: From 7044 articles, 13 retrospective studies were included in the final analysis. Three studies had "not serious" bias and the other 10 studies had serious or very serious bias. The total number of patients in the included studies was 1799 patients. Five studies included single-level ACDF, 2 studies included multi-level ACDF, and 6 studies included single or multi-level ACDF. On meta-analysis, the significant risk factors associated with ASD development were reduced postoperative cervical lordosis (mean difference [MD] = 3.35°, P = .002), reduced last-follow-up cervical lordosis (MD = -3.02°, P = .0003), increased preoperative to postoperative cervical sagittal alignment change (MD = -3.68°, P = .03), and the presence of developmental cervical canal stenosis (Odds ratio [OR] = 4.17, P < .001). CONCLUSIONS: Decreased postoperative cervical lordosis, greater change in cervical sagittal alignment and developmental cervical canal stenosis were associated with an increased risk of ASD following ACDF.

Surgeon Preference Regarding Wound Dressing Management in Lumbar Fusion Surgery: An AO Spine Global Cross-Sectional Study.

OBJECTIVE: To evaluate the global practice pattern of wound dressing use after lumbar fusion for degenerative conditions. METHODS: A survey issued by AO Spine Knowledge Forums Deformity and Degenerative was sent out to AO Spine members. The type of postoperative dressing employed, timing of initial dressing removal, and type of subsequent dressing applied were investigated. Differences in the type of surgery and regional distribution of surgeons' preferences were analyzed. RESULTS: Right following surgery, 60.6% utilized a dry dressing, 23.2% a plastic occlusive dressing, 5.7% glue, 6% a combination of glue and polyester mesh, 2.6% a wound vacuum, and 1.2% other dressings. The initial dressing was removed on postoperative day 1 (11.6%), 2 (39.2%), 3 (20.3%), 4 (1.7%), 5 (4.3%), 6 (0.4%), 7 or later (12.5%), or depending on drain removal (9.9%). Following initial dressing removal, 75.9% applied a dry dressing, 17.7% a plastic occlusive dressing, and 1.3% glue, while 12.1% used no dressing. The use of no additional coverage after initial dressing removal was significantly associated with a later dressing change (p < 0.001). Significant differences emerged after comparing dressing management among different AO Spine regions (p < 0.001). CONCLUSION: Most spine surgeons utilized a dry or plastic occlusive dressing initially applied after surgery. The first dressing was more frequently changed during the first 3 postoperative days and replaced with the same type of dressing. While dressing policies tended not to vary according to the type of surgery, regional differences suggest that actual practice may be based on personal experience rather than available evidence.

Riluzole for Degenerative Cervical Myelopathy: A Secondary Analysis of the CSM-PROTECT Trial.

Importance: The modified Japanese Orthopaedic Association (mJOA) scale is the most common scale used to represent outcomes of degenerative cervical myelopathy (DCM); however, it lacks consideration for neck pain scores and neglects the multidimensional aspect of recovery after surgery. Objective: To use a global statistical approach that incorporates assessments of multiple outcomes to reassess the efficacy of riluzole in patients undergoing spinal surgery for DCM. Design, Setting, and Participants: This was a secondary analysis of prespecified secondary end points within the Efficacy of Riluzole in Surgical Treatment for Cervical Spondylotic Myelopathy (CSM-PROTECT) trial, a multicenter, double-blind, phase 3 randomized clinical trial conducted from January 2012 to May 2017. Adult surgical patients with DCM with moderate to severe myelopathy (mJOA scale score of 8-14) were randomized to receive either riluzole or placebo. The present study was conducted from July to December 2023. Intervention: Riluzole (50 mg twice daily) or placebo for a total of 6 weeks, including 2 weeks prior to surgery and 4 weeks following surgery. Main Outcomes and Measures: The primary outcome measure was a difference in clinical improvement from baseline to 1-year follow-up, assessed using a global statistical test (GST). The 36-Item Short Form Health Survey Physical Component Score (SF-36 PCS), arm and neck pain numeric rating scale (NRS) scores, American Spinal Injury Association (ASIA) motor score, and Nurick grade were combined into a single summary statistic known as the global treatment effect (GTE). Results: Overall, 290 patients (riluzole group, 141; placebo group, 149; mean [SD] age, 59 [10.1] years; 161 [56%] male) were included. Riluzole showed a significantly higher probability of global improvement compared with placebo at 1-year follow-up (GTE, 0.08; 95% CI, 0.00-0.16; P = .02). A similar favorable global response was seen at 35 days and 6 months (GTE for both, 0.07; 95% CI, -0.01 to 0.15; P = .04), although the results were not statistically significant. Riluzole-treated patients had at least a 54% likelihood of achieving better outcomes at 1 year compared with the placebo group. The ASIA motor score and neck and arm pain NRS combination at 1 year provided the best-fit parsimonious model for detecting a benefit of riluzole (GTE, 0.11; 95% CI, 0.02-0.16; P = .007). Conclusions and Relevance: In this secondary analysis of the CSM-PROTECT trial using a global outcome technique, riluzole was associated with improved clinical outcomes in patients with DCM. The GST offered probability-based results capable of representing diverse outcome scales and should be considered in future studies assessing spine surgery outcomes.

Postoperative C5 Palsy after Anterior or Posterior Decompression for Degenerative Cervical Myelopathy: A Subgroup Analysis of the Multicenter, Prospective, Randomized, Phase III, CSM-Protect Clinical Trial.

STUDY DESIGN: Retrospective cohort study of prospectively accrued data. OBJECTIVE: To evaluate a large, prospective, multicentre dataset of surgically-treated DCM cases on the contemporary risk of C5 palsy with surgical approach. SUMMARY OF BACKGROUND DATA: The influence of surgical technique on postoperative C5 palsy after decompression for degenerative cervical myelopathy (DCM) is intensely debated. Comprehensive analyses are needed using contemporary data and accounting for covariates. METHODS: Patients with moderate to severe DCM were prospectively enrolled in the multicenter, randomized CSM-Protect clinical trial and underwent either anterior or posterior decompression between Jan 31, 2012, to May 16, 2017. The primary outcome was the incidence of postoperative C5 palsy, defined as onset of muscle weakness by at least one grade in manual muscle test at the C5 myotome with slight or absent sensory disruption after cervical surgery. Two comparative cohorts were made based on anterior or posterior surgical approach. Multivariate hierarchical mixed-effects logistic regression was used to estimate odds ratios (OR) with 95% confidence intervals (CI) for C5 palsy. RESULTS: A total of 283 patients were included, and 53.4% underwent posterior decompression. The total incidence of postoperative C5 palsy was 7.4% and was significantly higher in patients that underwent posterior decompression compared to anterior decompression (11.26% vs. 3.03%, P=0.008). After multivariable regression, posterior approach was independently associated with greater than four times the likelihood of postoperative C5 palsy (P=0.017). Rates of C5 palsy recovery were comparable between the two surgical approaches. CONCLUSION: The odds of postoperative C5 palsy are significantly higher after posterior decompression compared to anterior decompression for DCM. This may influence surgical decision-making when there is equipoise in deciding between anterior and posterior treatment options for DCM. LEVEL OF EVIDENCE: Therapeutic Level II.

Motor Strength Measurements Obtained Using an Inexpensive Spring Tensiometer and a Clinical Dynamometer Correlated Well: A Prospective Cohort Study.

OBJECTIVE: Manual muscle strength testing is the primary method for testing muscle strength in clinical settings but is highly subjective. An objective measure of muscle strength can be obtained using a handheld dynamometer, but its cost inhibits its widespread usage. We hypothesized that a spring tensiometer (ST) could be an objective tool that can be used as a viable alternative to a dynamometer. METHODS: Twenty-six outpatients were included, and the strengths of several muscle groups were measured using tensiometers and dynamometers. A paired t-test and Pearson's correlation coefficient and Bland-Altman plot analyses were used to estimate the reliability and measurement accuracy of both tools. Multiple regression analysis was performed to identify the factors contributing to the measurement gap between the two instruments. RESULTS: A total of 260 muscle force values were evaluated. Pearson's correlation coefficient and Bland-Altman analyses indicated that the measurements of the two instruments were strongly correlated and highly accurate. In the multiple regression analysis, the gap between the two instruments was significantly related to the original muscle strength and muscle part but was not significantly related to sex, age, body mass index, or laterality. For biceps and triceps muscle groups, the correlations were particularly strong and accurate, indicating that a tensiometer could be well substituted for a dynamometer. CONCLUSIONS: Our data show that a ST is similar to a dynamometer in terms of precision. A ST is an inexpensive alternative to a dynamometer and more accessible for clinical use than a dynamometer.

Clinical risk factors associated with the development of adjacent segment disease in patients undergoing ACDF: A systematic review.

BACKGROUND CONTEXT: Cervical fusion for degenerative disorders carries a known risk of adjacent segment disease (ASD), a complication that often requires surgical intervention to relieve symptoms. Proposed risk factors for development of ASD include both clinical and radiographic patient characteristics. However, the true impact of these risk factors is less understood due to limitations in sample sizes and loss to follow-up in individual studies. PURPOSE: To review and critically examine current literature on the clinical risk factors associated with development of ASD in the cervical spine following ACDF. STUDY DESIGN: Systematic Review and Meta-Analysis. METHODS: We systematically reviewed the literature in December 2019 according to the PRISMA guidelines. Methodological quality of included papers and quality of evidence were evaluated according to MINORS and GRADE framework. Meta-analysis was performed to compute the odds ratio(OR)with corresponding 95% confidence interval(CI)for dichotomous data, and mean difference(MD) with 95% CI for continuous variables. RESULTS: 6,850 records were obtained using database query. Title/abstract screening resulted in 19 articles for full review, from which 10 papers met the criteria for analysis. There were no significant differences in gender (OR 0.99, 95% CI 0.75-1.30), BMI (MD -0.09, 95% CI -0.46 to 0.29), smoking (OR 1.13, 95% CI 0.80-1.59), alcohol (OR 1.07, 95% CI 0.70-1.64), diabetes (OR 0.85, 95% CI 0.56-1.31), number of segments fused (OR 0.86, 95% CI 0.64-1.16), and preoperative JOA (MD -0.50, 95% CI -1.04 to 0.04). Age (MD 3.21, 95% CI 2.00-4.42), congenital/developmental stenosis (OR 1.94, 95% CI 1.06-3.56), preoperative NDI (MD 4.18, 95% CI 2.11 to 6.26), preoperative VAS (neck) (MD 0.54 95% CI 0.09-0.99), and preoperative VAS (arm) (MD 0.98, 95% CI 0.43-1.34) were found to be statistically significant risk factors. CONCLUSION: Patients with congenital stenosis, advanced age, and high preoperative NDI are at increased risk of developing ASD.

Does the choice of chemoprophylaxis affect the prevention of deep vein thrombosis in lumbar fusion surgery? A systematic review of the literature.

Introduction: To date, the available guidance on venous thromboembolism (VTE) prevention in elective lumbar fusion surgery is largely open to surgeon interpretation and preference without any specific suggested chemoprophylactic regimen. Research question: This study aimed to comparatively analyze the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) with the use of commonly employed chemoprophylactic agents such as unfractionated heparin (UH) and low molecular weight heparin (LMWH) in lumbar fusion surgery. Material and methods: An independent systematic review of four scientific databases (PubMed, Scopus, clinicaltrials.gov, Web of Science) was performed to identify relevant articles as per the preferred reporting in systematic reviews and meta-analysis (PRISMA) guidelines. Studies reporting on DVT/PE outcomes of lumbar fusion surgery in adult patients with UH or LMWH chemoprophylaxis were included for analysis. Analysis was performed using the Stata software. Results: Twelve studies with 8495 patients were included in the analysis. A single-arm meta-analysis of the included studies found a DVT incidence of 14% (95%CI [8%-20%]) and 1% (95%CI [-6% - 8%]) with LMWH and UH respectively. Both the chemoprophylaxis agents prevented PE with a noted incidence of 0% (95%CI [0%-0.1%]) and 0% (95%CI [0%-1%]) with LMWH and UH respectively. The risk of bleeding-related complications with the usage of LMWH and UH was 0% (95% CI [0.0%-0.30%]) and 3% (95% CI [0.3%-5%]) respectively. Discussion and conclusion: Both LMWH and UH reduces the overall incidence of DVT/PE, but there is a paucity of evidence analyzing the comparative effectiveness of the chemoprophylaxis regimens in lumbar fusion procedures. The heterogeneity in data prevents any conclusions, as there remains an evidence gap. We recommend future high-quality randomized controlled trials to investigate in this regard to help develop recommendations on thromboprophylaxis usage.

Surgeon Preferences Worldwide in Wound Drain Utilization in Open Lumbar Fusion Surgery for Degenerative Pathologies.

STUDY DESIGN: Cross-sectional survey. OBJECTIVE: Although literature does not recommend routine wound drain utilization, there is a disconnect between the evidence and clinical practice. This study aims to explore into this controversy and analyze the surgeon preferences related to drain utilization, and the factors influencing drain use and criterion for removal. METHODS: A survey was distributed to AO Spine members worldwide. Surgeon demographics and factors related to peri-operative drain use in 1 or 2-level open fusion surgery for lumbar degenerative pathologies were collected. Multivariate analyses by drain utilization, and criterion of removal were conducted. RESULTS: 231 surgeons participated, including 220 males (95.2%), orthopedics (178, 77.1%), and academic/university-affiliated (114, 49.4%). Most surgeons preferred drain use (186, 80.5%) and subfascial drains (169, 73.2%). Drains were removed based on duration by 52.87% of the surgeons, but 27.7% removed drains based on outputs. On multivariable analysis, significant predictors of drain use were surgeon's aged 35-44 (OR = 11.9, 95% CI = 1.2-117.2, P = .034), 45-54 (29.1, 3.1-269.6, P = .003), 55-64 (8.9, 1.4-56.5, .019), and wound closure using coaptive films (6.0, 1.2-29.0, P = .025). Additionally, surgeons from Asia Pacific (OR = 5.19, 95% CI = 1.65-16.38, P = .005), Europe (3.55, 1.22-10.31, P = .020), and Latin America (4.40, 1.09-17.83, .038) were more likely to remove drain based on time duration, but surgeons <5 years of experience (10.23, 1.75-59.71, P = .010) were more likely to remove drains based on outputs. CONCLUSIONS: Most spine surgeons worldwide prefer to place a subfascial wound drain for degenerative open lumbar surgery. The choice for drain placement is associated with the surgeon's age and use of coaptive films for wound closure, while the criterion for drain removal is associated with the surgeons' region of practice and experience.

Research Practices and Needs Among Spine Surgeons Worldwide.

OBJECTIVE: Resource allocation to research activities is challenging and there is limited evidence to justify decisions. Members of AO Spine were surveyed to understand the research practices and needs of spine surgeons worldwide. METHODS: An 84-item survey was distributed to the AO Spine community in September of 2020. Respondent demographics and insights regarding research registries, training and education, mentorship, grants and financial support, and future directions were collected. Responses were anonymous and compared among regions. RESULTS: A total of 333 spine surgeons representing all geographic regions responded; 52.3% were affiliated with an academic/university hospital, 91.0% conducted clinical research, and 60.9% had 5+ years of research experience. There was heterogeneity among research practices and needs across regions. North American respondents had more research experience (P = .023), began conducting research early on (P < .001), had an undergraduate science degree (P < .001), and were more likely to have access to a research coordinator or support staff (P = .042) compared to other regions. While all regions expressed having the same challenges in conducting research, Latin America, and Middle East/Northern Africa respondents were less encouraged to do research (P < .001). Despite regional differences, there was global support for research registries and research training and education. CONCLUSION: To advance spine care worldwide, spine societies should establish guidelines, conduct studies on pain management, and support predictive analytic modeling. Tailoring local/regional programs according to regional needs is advised. These results can assist spine societies in developing long-term research strategies and provide justified rationale to governments and funding agencies.

Representativeness of the American Spine Registry: a comparison of patient characteristics with the National Inpatient Sample.

OBJECTIVE: The American Spine Registry (ASR) is a collaborative effort between the American Academy of Orthopaedic Surgeons and the American Association of Neurological Surgeons. The goal of this study was to evaluate how representative the ASR is of the national practice with spinal procedures, as recorded in the National Inpatient Sample (NIS). METHODS: The authors queried the NIS and the ASR for cervical and lumbar arthrodesis cases performed during 2017-2019. International Classification of Diseases, 10th Revision and Current Procedural Terminology codes were used to identify patients undergoing cervical and lumbar procedures. The two groups were compared for the overall proportion of cervical and lumbar procedures, age distribution, sex, surgical approach features, race, and hospital volume. Outcomes available in the ASR, such as patient-reported outcomes and reoperations, were not analyzed due to nonavailability in the NIS. The representativeness of the ASR compared to the NIS was assessed via Cohen's d effect sizes, and absolute standardized mean differences (SMDs) of < 0.2 were considered trivial, whereas > 0.5 were considered moderately large. RESULTS: A total of 24,800 arthrodesis procedures were identified in the ASR for the period between January 1, 2017, and December 31, 2019. During the same time period, 1,305,360 cases were recorded in the NIS. Cervical fusions comprised 35.9% of the ASR cohort (8911 cases) and 36.0% of the NIS cohort (469,287 cases). The two databases presented trivial differences in terms of patient age and sex for all years of interest across both cervical and lumbar arthrodeses (SMD < 0.2). Trivial differences were also noted in the distribution of open versus percutaneous procedures of the cervical and lumbar spine (SMD < 0.2). Among lumbar cases, anterior approaches were more common in the ASR than in the NIS (32.1% vs 22.3%, SMD = 0.22), but the discrepancy among cervical cases in the two databases was trivial (SMD = 0.03). Small differences were illustrated in terms of race, with SMDs < 0.5, and a more significant discrepancy was identified in the geographic distribution of participating sites (SMDs of 0.7 and 0.74 for cervical and lumbar cases, respectively). For both of these measures, SMDs in 2019 were smaller than those in 2018 and 2017. CONCLUSIONS: The ASR and NIS databases presented a very high similarity in proportions of cervical and lumbar spine surgeries, as well as similar distributions of age and sex, and distribution of open versus endoscopic approach. Slight discrepancies in anterior versus posterior approach among lumbar cases and patient race, and more significant discrepancies in geographic representation were also identified, yet decreasing trends in differences suggested the improving representativeness of the ASR over the course of time and its progressive growth. These conclusions are important to underline the external validity of quality investigations and research conclusions to be drawn from analyses in which the ASR is used.

Catastrophic acute failure of pelvic fixation in adult spinal deformity requiring revision surgery: a multicenter review of incidence, failure mechanisms, and risk factors.

OBJECTIVE: There are few prior reports of acute pelvic instrumentation failure in spinal deformity surgery. The objective of this study was to determine if a previously identified mechanism and rate of pelvic fixation failure were present across multiple institutions, and to determine risk factors for these types of failures. METHODS: Thirteen academic medical centers performed a retrospective review of 18 months of consecutive adult spinal fusions extending 3 or more levels, which included new pelvic screws at the time of surgery. Acute pelvic fixation failure was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS: Failure occurred in 37 (5%) of 779 cases and consisted of either slippage of the rods or displacement of the set screws from the screw tulip head (17 cases), screw shaft fracture (9 cases), screw loosening (9 cases), and/or resultant kyphotic fracture of the sacrum (6 cases). Revision strategies involved new pelvic fixation and/or multiple rod constructs. Six patients (16%) who underwent revision with fewer than 4 rods to the pelvis sustained a second acute failure, but no secondary failures occurred when at least 4 rods were used. In the univariate analysis, the magnitude of surgical correction was higher in the failure cohort (higher preoperative T1-pelvic angle [T1PA], presence of a 3-column osteotomy; p < 0.05). Uncorrected postoperative deformity increased failure risk (pelvic incidence-lumbar lordosis mismatch > 10°, higher postoperative T1PA; p < 0.05). Use of pelvic screws less than 8.5 mm in diameter also increased the likelihood of failure (p < 0.05). In the multivariate analysis, a larger preoperative global deformity as measured by T1PA was associated with failure, male patients were more likely to experience failure than female patients, and there was a strong association with implant manufacturer (p < 0.05). Anterior column support with an L5-S1 interbody fusion was protective against failure (p < 0.05). CONCLUSIONS: Acute catastrophic failures involved large-magnitude surgical corrections and likely resulted from high mechanical strain on the pelvic instrumentation. Patients with large corrections may benefit from anterior structural support placed at the most caudal motion segment and multiple rods connecting to more than 2 pelvic fixation points. If failure occurs, salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.

Demographic, clinical, and operative risk factors associated with postoperative adjacent segment disease in patients undergoing lumbar spine fusions: a systematic review and meta-analysis.

BACKGROUND CONTEXT: Adjacent segment disease (ASD) is a potential complication following lumbar spinal fusion. PURPOSE: This study aimed to demonstrate the demographic, clinical, and operative risk factors associated with ASD development following lumbar fusion. STUDY DESIGN/SETTING: Systematic review and meta-analysis. PATIENT SAMPLE: We identified 35 studies that reported risk factors for ASD, with a total number of 7,374 patients who had lumbar spine fusion. OUTCOME MEASURES: We investigated the demographic, clinical, and operative risk factors for ASD after lumbar fusion. METHODS: A literature search was done using PubMed, Embase, Medline, Scopus, and the Cochrane library databases from inception to December 2019. The methodological index for non-randomized studies (MINORS) criteria was used to assess the methodological quality of the included studies. A meta-analysis was done to calculate the odds ratio (OR) with the 95% confidence interval (CI) for dichotomous data and mean difference (MD) with 95% CI for continuous data. RESULTS: Thirty-five studies were included in the qualitative analysis, and 22 studies were included in the meta-analyses. The mean quality score based on the MINORS criteria was 12.4±1.9 (range, 8-16) points. Significant risk factors included higher preoperative body mass index (BMI) (mean difference [MD]=1.97 kg/m2; 95% confidence interval [CI]=1.49-2.45; p<.001), floating fusion (Odds ratio [OR]=1.78; 95% CI=1.32-2.41; p<.001), superior facet joint violation (OR=10.43; 95% CI=6.4-17.01; p<.001), and decompression outside fusion construct (OR=1.72; 95% CI=1.25-2.37; p<.001). CONCLUSIONS: The overall level of evidence was low to very low. Higher preoperative BMI, floating fusion, superior facet joint violation, and decompression outside fusion construct are significant risk factors of development of ASD following lumbar fusion surgeries.

Long-Segmental Posterior Fusion Combined With Vertebroplasty and Wiring: Alternative Surgical Technique for Kummell's Disease With Neurologic Deficits-A Retrospective Case Series.

PURPOSE: Various surgical methods have been reported for Kummell's disease with neurologic deficits. The aim of this study was to introduce long-segmental posterior fusion (LPF) combined with vertebroplasty (VP) and wiring as an alternative surgical technique. MATERIAL AND METHODS: We retrospectively analyzed 10 patients undergoing posterior decompression and LPF combined with VP and wiring for Kummell's disease with neurologic deficits from January 2011 to December 2014. The radiologic outcomes included the local kyphotic angle (LKA) and segmental kyphotic angle (SKA). Clinical outcomes, including the visual analog scale (VAS), the Oswestry Disability Index (ODI) and the Frankel grade were assessed. Surgery-related complications were also evaluated. RESULTS: The mean age of the included patients was 77 ± 8 years with a mean follow-up period of 31.4 ± 4.9 months and a mean bone mineral density of -3.5 ± 0.7 (T-score). The mean operation time was 220 ± 32.3 minutes with a mean blood loss of 555 ± 125.7 mL. The preoperative LKA and SKA were significantly corrected postoperatively (37.9 ± 8.7° vs. 15.3 ± 5.3°, p = 0.005 for LKA; 21.3 ± 5.1° vs. 7.6 ± 2.8°, p = 0.005 for SKA) without a loss of correction at the last follow-up. The VAS and ODI were also significantly improved (7.7 ± 1.1 vs. 3.0 ± 1.6, p = 0.007 for VAS; 90.3 ± 8.9 vs. 49.6 ± 22.7, p = 0.007 for ODI). The Frankel grade of all patients was improved by at least 1 or 2 grades at the last follow-up. Surgery-related complications such as intraoperative cement leakage and implant loosening during the follow-up were not observed. CONCLUSIONS: LPF combined with VP and wiring might be an effective surgical option for Kummell's disease with neurologic deficits, especially for the elderly patients with morbidities. LEVEL OF EVIDENCE: level IV.