Faculty Bibliography

PURPOSE/OBJECTIVE:Current decision-making in multilevel cervical fusion weighs the potential to protect adjacent levels and reduce reoperation risk by crossing the cervicothoracic junction (C7/T1) against increased operative time and risk of complication. Careful planning is required, and the planned distal and adjacent levels should be assessed for degenerative disc disease (DDD). This study assessed whether DDD at the cervicothoracic junction was associated with DDD, disc height, translational motion, or angular variation in the adjacent superior (C6/C7) or inferior (T1/T2) levels. METHODS:This study retrospectively analyzed 93 cases with kinematic MRI. Cases were randomly selected from a database with inclusion criteria being no prior spine surgery and images having sufficient quality for analysis. DDD was assessed using Pfirrmann classification. Vertebral body bone marrow lesions were assessed using Modic changes. Disc height was measured at the mid-disc in neutral and extension. Translational motion and angular variation were calculated by assessing translational or angular motion segment integrity respectively in flexion and extension. Statistical associations were assessed with scatterplots and Kendall's tau. RESULTS:DDD at C7/T1 was positively associated with DDD at C6/C7 (tau = 0.53, p < 0.01) and T1/T2 (tau = 0.58, p < 0.01), with greater disc height in neutral position at T1/T2 (tau = 0.22, p < 0.01), and with greater disc height in extended position at C7/T1 (tau = 0.17, p = 0.04) and at T1/T2 (tau = 0.21, p < 0.01). DDD at C7/T1 was negatively associated with angular variation at C6/C7 (tau = - 0.23, p < 0.01). No association was appreciated between DDD at C7/T1 and translational motion. CONCLUSION/CONCLUSIONS:The association of DDD at the cervicothoracic junction with DDD at the adjacent levels emphasizes the necessity for careful selection of the distal level in multilevel fusion in the distal cervical spine.

STUDY DESIGN/METHODS:A prospective case-control study. OBJECTIVE:To analyze global coronal malalignment (GCM) in degenerative lumbar scoliosis (DLS) and to prospectively investigate the performance of priority-matching correction technique on preventing postoperative coronal imbalance. METHODS:A total of 444 DLS inpatients and outpatients were recruited. GCMs were classified into 2 types: Type 1, GCM with thoracolumbar (TL/L) curve as the main contribution on coronal imbalance; Type 2, GCM with lumbosacral (LS) curve as the main contribution on coronal imbalance. Patients receiving priority-matching correction were assigned to Group P-M and receiving traditional correction were assigned to Group T form August 2020. The fundamental principle of priority-matching technique was to first correct the key curve contributing to coronal imbalance rather than the curve with greater magnitude. RESULTS:Type 1 GCM accounted for 45% and Type 2 GCM accounted for 55% of patients. Type 2 GCM was detected to have greater LS Cobb angle and L4 tilt. At 1-year follow-up, 29.8% of patients with Type 2 GCM, whereas 11.7% of patients with Type 1 GCM were observed to have postoperative coronal decompensation. Patients with postoperative imbalance were revealed to have greater preoperative LS Cobb angle and L4 tilt and smaller correction extent of LS curve and L4 tilt. 6.25% of patients developed postoperative coronal imbalance in Group P-M, whereas 40.5% developed in Group T. CONCLUSION/CONCLUSIONS:Highlighting priority and aggressive correction of the key curve to coronal imbalance, priority-matching technique was proved to be able to limit the development of postoperative coronal decompensation.

STUDY DESIGN/METHODS:Retrospective Upright MRI Study. OBJECTIVES/OBJECTIVE:Determine the relationship between lumbar disc herniation and presence of the nerve root sedimentation sign on upright kinematic MRI patients. METHODS:T2-weighted axial upright kMRI images of 100 patients with the presence of disc herniation in at least 1 lumbar disc between L1/L2 and L5/S1 were obtained. Sedimentation sign, spinal canal anterior-posterior (AP) diameter, disc height, disc herniation size, type of herniation, and zone of herniation were evaluated. A positive sedimentation sign was defined as having either the majority of nerve roots running ventrally or centrally in the canal or conglomeration of the nerve roots at the mid-disc level. Herniation types were defined as either no herniation, disc bulge, protrusion, extrusion, or sequestration. Zones of herniation were categorized as either central, lateral, or far lateral. RESULTS:The kappa value of intra-observer reliability was .915. The kappa value of disc levels with a negative sedimentation sign were seen more frequently (n = 326, 65.2%) than those with a positive sedimentation sign (n = 174, 34.8%). The spinal canal AP diameter was significantly decreased at the L3/L4 and L4/L5 level in patients with a positive sedimentation sign. Discs with a positive sedimentation sign had a larger average size of disc herniation compared to those with a negative sign at all levels. A relationship between positivity of the sedimentation sign and disc herniation type was significant at L2/L3, L3/L4, and L4/L5. CONCLUSIONS:Patients with a positive sedimentation sign were seen to have larger disc herniations and more severely degenerated discs.

Study design: This study constitutes a systematic review of the literature. Objective: The aim of this study was to identify and present all available studies that report on the costs of osteobiologics used in anterior cervical discectomy and fusion (ACDF). Methods: The literature was systematically reviewed to identify studies with specific inclusion criteria: (1) randomized controlled trials and observational studies, (2) in adult patients, (3) with herniated disc(s) or degenerative cervical spine disease, (4) reporting on either direct or indirect costs of using specific osteobiologics in an ACDF operation. (5) Only studies in English were included. The quality of the included studies was assessed using the MINORS and RoB 2.0 tools. Results: Overall, 14 articles were included; one randomized controlled trial and 13 observational studies. The most commonly used osteobiologics other than autograft/iliac crest bone graft (ICBG) were allograft and bone morphogenetic protein (BMP). None of the studies was reported to be industry-supported. There was considerable heterogeneity on the reported costs. Overall, most studies reported on surgery-related costs, such as anesthesia, operating room, surgical materials and surgeon"™s fee. Only two studies, both using allograft, reported the exact cost of the osteobiologic used (450 GBP, $700). Some of the studies reported on the cost of care during hospitalization for the surgical operation, such as radiology studies, emergency room costs, cardiologic evaluation, laboratory studies, pharmacy costs, and room costs. Only a few studies reported on the cost of follow-up, reoperation, and physical therapy and rehabilitation. Conclusion: Based on the data of this current systematic review, no recommendations can be made regarding the cost-effectiveness of using osteobiologics in ACDF. Given the high costs of osteobiologics, this remains a topic of importance. The design of future studies on the subject should include cost effectiveness.

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BACKGROUND CONTEXT/BACKGROUND: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/OBJECTIVE: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/METHODS: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/CONCLUSIONS:Patients with congenital stenosis, advanced age, and high preoperative NDI are at increased risk of developing ASD.

INTRODUCTION/UNASSIGNED: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/UNASSIGNED: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/UNASSIGNED: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/UNASSIGNED: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/UNASSIGNED: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.