Faculty Bibliography

STUDY DESIGN/METHODS:Systematic literature review. OBJECTIVE:To analyze the literature and describe the evidence supporting osteobiologic use in revision anterior cervical discectomy and fusion (ACDF) surgery. METHODS:A systematic search of PubMed/MEDLINE, EMBASE, Cochrane library, and ClinicalTrials.gov databases was conducted for literature reporting the use of osteobiologics in revision ACDF. We searched for studies reporting outcomes of using any osteobiologic use in revision ACDF surgeries (independently of the number of levels) in the above databases. RESULTS:There are currently no studies in the literature describing the outcome and comparative efficacy of diverse osteobiologic agents in the context of revision ACDF surgery. A majority of the current evidence is based only upon studies involving primary ACDF surgery. CONCLUSION/CONCLUSIONS:The current study highlights the paucity of literature evidence on the role of diverse osteobiologics in revision ACDF, and foregrounds the need for high-quality evidence on this subject.

STUDY DESIGN/METHODS:Methodological study for guideline development. OBJECTIVE:AO Spine Guideline for Using Osteobiologics (AO-GO) project for spine degenerative pathologies was an international, multidisciplinary collaborative initiative to identify and evaluate evidence on existing use of osteobiologics in Anterior Cervical Fusion and Decompression (ACDF). The aim was to formulate precisely defined, clinically relevant and internationally applicable guidelines ensuring evidence-based, safe and effective use of osteobiologics, considering regional preferences and cost-effectiveness. METHODS:Guideline was completed in two phases: Phase 1- evidence synthesis; Phase 2- recommendation development based on the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. In Phase 1, key questions identified by a panel of experts were addressed in a series of systematic reviews of randomized and non-randomized studies. In Phase 2, the GRADE approach was used to formulate a series of recommendations, including expert panel discussions via web calls and face-to-face meetings. DISCUSSION/CONCLUSIONS:AO-GO aims to bridge an important gap between evidence and use of osteobiologics in spine fusion surgeries. Owing to differences in osteobiologics preparation and functional characteristics, regulatory requirements for approval may vary, therefore it is highly likely that these products enter market without quality clinical trials. With a holistic approach the guideline aims to facilitate evidence-based, patient-oriented decision-making processes in clinical practice, thus stimulating further evidence-based studies regarding osteobiologics usage in spine surgeries. In Phase 3, the guideline will be disseminated and validated using prospectively collected clinical data in a separate effort of the AO Spine Knowledge Forum Degenerative in a global multicenter clinical study.

STUDY DESIGN/METHODS:Systematic Review and Meta-Analysis. OBJECTIVES/OBJECTIVE:To compare complication incidence in patients with or without the use of recombinant human Bone Morphogenic Protein-2 (BMP2) undergoing anterior cervical discectomy and fusion (ACDF) for degenerative conditions. METHODS:A systematic search of eight online databases was conducted using PRISMA guidelines. Inclusion criteria included English language studies with a minimum of 10 adult patients undergoing instrumented ACDF surgery for a degenerative spinal condition in which BMP2 was used in all patients or one of the treatment arms. Studies with patients undergoing circumferential fusions, with non-degenerative indications, or which did not report post-operative complication data were excluded. Patients with and without BMP2 were compared in terms of the incidence of dysphagia/dysphonia, anterior soft tissue complications (hematoma, seroma, infection, dysphagia/dysphonia), nonunion, medical complications, and new neurologic deficits. RESULTS:= .66), and additional medical complications (RR = 1.53, CI 95% .98-2.38, P = .06) were not found to be statistically different between the groups. CONCLUSIONS:This meta-analysis identified a high rate of arthrodesis when BMP2 was used in ACDF, but confirmed increased rates of dysphagia and anterior soft tissue complications. Surgeons may consider reserving BMP2 implementation for cases with a high risk of non-union, and should be aware of the risk of airway compromise.

STUDY DESIGN/METHODS:Systematic literature review. OBJECTIVES/OBJECTIVE:In this study we assessed evidence for the use of osteobiologics in single vs multi-level anterior cervical discectomy and fusion (ACDF) in patients with cervical spine degeneration. The primary objective was to compare fusion rates after single and multi-level surgery with different osteobiologics. Secondary objectives were to compare differences in patient reported outcome measures (PROMs) and complications. METHODS:After a global team of reviewers was selected, a systematic review using different repositories was performed, confirming to PRISMA and GRADE guidelines. In total 1206 articles were identified and after applying inclusion and exclusion criteria, 11 articles were eligible for analysis. Extracted data included fusion rates, definition of fusion, patient reported outcome measures, types of osteobiologics used, complications, adverse events and revisions. RESULTS:Fusion rates ranged from 87.7% to 100% for bone morphogenetic protein 2 (BMP-2) and 88.6% to 94.7% for demineralized bone matrix, while fusion rates reported for other osteobiologics were lower. All included studies showed PROMs improved significantly for each osteobiologic. However, no differences were reported when comparing osteobiologics, or when comparing single vs multi-level surgery specifically. CONCLUSION/CONCLUSIONS:The highest fusion rates after 2-level ACDF for cervical spine degeneration were reported when BMP-2 was used. However, PROMs did not differ between the different osteobiologics. Further blinded randomized trials should be performed to compare the use of BMP-2 in single vs multi-level ACDF specifically.

STUDY DESIGN/METHODS:Systematic literature review. OBJECTIVES/OBJECTIVE:To analyze the evidence available reporting complications in single or two-level anterior cervical discectomy and fusion (ACDF) using a demineralized bone matrix (DBM), hydroxyapatite (HA), or beta-tricalcium phosphate (β-TCP). METHODS:A systematic review of the literature using PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov databases was performed in August 2020 to identify studies reporting complications in one or two-level ACDF surgery using DBM, HA, or β-TCP. The study was reported following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. RESULTS:A total of 1857 patients were included, 981 male and 876 female, across 17 articles; 5 prospective, and 12 retrospectives. We noted heterogeneity among the included studies concerning the study design and combination of graft materials utilized in them. However, we noted a higher incidence of adjacent segment disease (17.7%) and pseudoarthrosis (9.3%) in fusion constructs using DBM. Studies using β-TCP reported a higher incidence of pseudoarthrosis (28.2%) and implant failures (17.9%). CONCLUSIONS:Degenerative cervical conditions treated with one or two-level ACDF surgery using DBM, HA, or β-TCP with or without cervical plating are associated with complications such as adjacent segment disease, dysphagia, and pseudarthrosis. However, consequent to the study designs and clinical heterogeneity of the studies, it is not possible to correlate these complications accurately with any specific graft material employed. Further well-designed prospective studies are needed to correctly know the related morbidity of each graft used for achieving fusion in ACDF.

STUDY DESIGN/METHODS:Systematic review. OBJECTIVES/OBJECTIVE:The aim of this study is to analyze the complications related to multilevel anterior cervical discectomy and fusion (ACDF) using osteobiologics other than bone morphogenetic protein (BMP). METHODS:A systematic review of the literature was conducted using PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov databases. The search to identify studies reporting complications in multilevel ACDF surgery using osteobiologics other than bone morphogenetic protein was performed in August 2020. The study was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). RESULTS:A total of 584 articles were found after searching the databases and removing duplicates. Next, screening was performed in a double reviewer process, and 153 eligible articles-with 4 retrospective studies-in full-text were selected; these met all inclusion criteria. A total of 197 patients received 3-level ACDF, while 72 patients received 4-level ACDF. Osteobiologics were used in all selected articles, allograft was used in 4 studies, autologous bone graft was utilized in 3 articles, and hydroxyapatite was used in 1 article. The main complications reported were dysphagia, adjacent segment disease, and pseudarthrosis. CONCLUSIONS:Given the limited evidence, no conclusions on complications in multilevel ACDF using osteobiologics other than BMP could be made. However, descriptively, the most common complications found were dysphagia, adjacent segment disease, and pseudoarthrosis. Further prospective studies separately analyzing complications in multilevel ACDF by osteobiologics and a number of treated levels are needed.

STUDY DESIGN/METHODS:Systematic review. OBJECTIVE:Examine the clinical evidence for the use of osteobiologics in hybrid surgery (combined anterior cervical discectomy and fusion (ACDF) and total disc replacement (TDR)) in patients with multilevel cervical degenerative disc disease (DDD). METHODS:PubMed and Embase were searched between January 2000 and August 2020. Clinical studies investigating 18-80 year old patients with multilevel cervical DDD who underwent hybrid surgery with or without the use of osteobiologics were considered eligible. Two reviewers independently screened and assessed the identified articles. The methodological index for non-randomized studies (MINORS) tool and the risk of bias (RoB 2.0) assessment tool were used to assess risk of bias. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) was used to evaluate quality of evidence across studies per outcome. RESULTS:Eleven studies were included. A decrease in cervical range of motion was observed in most studies for both the hybrid surgery and the control groups consisting of stand-alone ACDF or TDR. Fusion rates of 70-100% were reported in both the hybrid surgery and control groups consisting of stand-alone ACDF. The hybrid surgery group performed better or comparable to the control group in terms of adjacent segment degeneration. Studies reported an improvement in visual analogue scale for pain and neck disability index values after surgery compared to preoperative scores for both treatment groups. The included studies had moderate methodological quality. CONCLUSIONS:There is insufficient evidence for assessing the use of osteobiologics in multilevel hybrid surgery and additional high quality and controlled research is deemed essential.

PURPOSE/OBJECTIVE:To evaluate the relationship between nerve root retraction time, post-operative radiculitis and patient reported outcomes. METHODS:Patients who underwent single- or multi-level lumbar discectomy between 2020 and 2022 for lumbar disk herniations were prospectively followed with pre-operative, interoperative and post-operative variables including radiculitis and patient reported outcomes including VAS, ODI and CAT domains Pain interference, Pain intensity and Physical function. Intraoperative nerve root retraction time was recorded. Paired sample two-tailed t-test and multivariate regression were utilized with p < 0.05 being significant. RESULTS:A total of 157 patients who underwent single- or multi-level endoscopic lumbar discectomy. Average patient age was 44 years, and 64% were male patients. Nerve retraction time ranged from 4 to 15 min. Eighteen percent reported new radiculitis at 2-weeks post-operatively. In patients with new-onset radiculitis 79.2% reported significantly worse VAS leg at 2 weeks post-operative (4.2 vs. 8.3, p < 0.001) compared to 12.5% who had improved VAS leg (9.3 vs. 7, p = 0.1181). Patients with radiculitis and worse VAS scores had substantially longer nerve retraction time (13.8 ± 7.5 min) than patients with improved VAS leg (6.7 ± 1.2 min). At 6 months, patients with longer nerve retraction time had no significant improvement in the ODI or CAT compared to the baseline. CONCLUSIONS:This is the first study in discectomy literature to show that new onset radiculitis and poorer outcomes in VAS leg correlate with longer nerve retraction time at early and later time points.

BACKGROUND/UNASSIGNED:Management of lumbar degenerative spondylolisthesis with decompression-only procedure has been performed for its added benefit of a shorter duration of surgery, lower blood loss, and shorter hospital stay. However, reported failure rates for decompression-only procedures vary depending on the methods utilized for decompression. Hence, we aim to identify the failure rates of individual methods of decompression-only procedures performed for degenerative lumbar spondylolisthesis. METHODS/UNASSIGNED:An independent systematic review of 4 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 guidelines. Studies reporting on failure rates defined by reoperation at the index level following decompression-only procedure for degenerative lumbar spondylolisthesis were included for analysis. Studies were appraised using ROBINS tool of Cochrane, and analysis was performed using the Open Meta[Analyst] software. RESULTS/UNASSIGNED:The overall failure rate of decompression-only procedure was 9.1% (95% confidence interval [CI] [6.5-11.7]). Furthermore, open decompression had failure rate of 10.9% (95% CI [6.0-15.8]), while microendoscopic decompression had failure rate of 6.7% (95% CI [2.9-10.6]). The failure rate gradually increased from 6.9% (95% CI [2.0-11.7]) at 1 year to 7% (95% CI [3.6-10.3]), 11.7% (95% CI [4.5-18.9]), and 11.7% (95% CI [6.6-16.7]) at 2, 3, and 5 years, respectively. Single level decompression had a failure rate of 9.6% (95% CI [6.3-12.9]), while multilevel decompression recorded a failure rate of 8.7% (95% CI [5.6-11.7]). CONCLUSION/UNASSIGNED:High-quality evidence on the decompression-only procedure for degenerative spondylolisthesis is limited. The decompression-only procedure had an overall failure rate of 9.1% without significant differences between the decompression techniques. LEVEL OF EVIDENCE/UNASSIGNED:Level IV. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND CONTEXT/BACKGROUND:Several studies have shown that factors such as insurance type and patient income are associated with different readmission rates following certain orthopaedic procedures. The literature, however, remains sparse with regard to these demographic characteristics and their associations to perioperative lumbar spine fusion outcomes. PURPOSE/OBJECTIVE:The purpose of this study was to assess the associations between hospital type, insurance type, and patient median income to both 30-day complication and readmission rates following lumbar spine fusion. PATIENT SAMPLE/METHODS:Patients who underwent primary lumbar spine fusion (n = 596,568) from 2010-2016 were queried from the National Readmissions Database (NRD). OUTCOME MEASURES/METHODS:Incidence of 30-day complication and readmission rates. METHODS:All relevant diagnoses and procedures were identified using International Classification of Disease, 9th and 10th Edition (ICD-9, 10) codes. Hospital types were categorized as metropolitan non-teaching (n = 212,131), metropolitan teaching (n = 364,752), and rural (n = 19,685). Insurance types included: Medicare (n = 213,534), Medicaid (n = 78,520), private insurance (n = 196,648), and out-of-pocket (n = 45,025). Patient income was divided into the following quartiles: Q1 (n = 112,083), Q2 (n = 145,755), Q3 (n = 156,276), and Q4 (n = 147,289), wherein quartile 1 corresponded to lower income ranges and quartile 4 to higher ranges. Statistical analysis was conducted in R. Kruskal-Wallis tests with Dunn's pairwise comparisons were performed to analyze differences in 30-day readmission and complication rates in patients who underwent lumbar spine fusion. Complications analyzed included infection, wound injury, hematoma, neurological injury, thromboembolic event, and hardware failure. RESULTS:< .001). Patients in Quartile 4 experienced significantly greater rates of hematoma formation compared to those in Quartiles 1 and 2 and were more likely to experience a thromboembolic event compared to all other groups. CONCLUSION/CONCLUSIONS:Patients undergoing lumbar spine fusion at metropolitan non-teaching hospitals and paying with private insurance had significantly lower 30-day readmission rates than their counterparts. Complications within 30 days following lumbar spine fusion were significantly higher in patients treated at metropolitan teaching hospitals and in Medicare and Medicaid beneficiaries. Aside from a few exceptions, however, patient income was generally not associated with differential complication rates.