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OBJECTIVE Anterior cervical discectomy and fusion (ACDF) is an established treatment for cervical degenerative disc disease; however, the procedure can cause loss of cervical spine range of motion and potentially accelerate adjacent segment degeneration. Cervical disc arthroplasty (CDA) seeks to preserve native motion of the cervical spine, which can theoretically reduce the incidence of adjacent level degeneration. The literature regarding the relative efficacy of ACDF versus CDA remains inconsistent. In this study, the authors investigate the difference in outcomes between ACDF and CDA and identify factors contributing to the heterogeneity in the literature. METHODS The Ovid, Embase, Scopus, Cochrane, and ClinicalTrials.gov databases were systematically searched from inception to September 5, 2023, for randomized controlled trials (RCTs) comparing ACDF and CDA for degenerative disc disease. Studies were extracted by two authors and verified by a third. Random-effects meta-analysis was performed. The primary outcome was the difference in clinical outcomes between the two surgical groups. The secondary outcomes were the differences in radiological outcomes, surgical characteristics, complication rates, and hospital lengths of stay. The study was registered with the International Prospective Register of Systematic Reviews (PROSPERO; registration no. CRD42023469204) and adhered to the PRISMA guidelines. RESULTS From 584 articles uploaded to the Covidence platform for screening, 35 studies derived from 25 RCTs were included in this systematic review and meta-analysis. A total of 4530 patients were treated with ACDF (2081) and CDA (2449). Forty-six percent of the patients (2063) were male, and the mean age of the study cohort was 45 ± 3 years. In terms of the primary outcome, CDA showed higher rates of neurological and overall success. Regarding the secondary outcomes, CDA demonstrated a significantly lower rate of adjacent level disease, higher rate of heterotopic ossification, and greater range of motion at the operated level. Additionally, CDA had lower rates of reoperation but significantly longer operative times than ACDF. The inclusion of myelopathic patients and variations in follow-up between the surgical groups contributed to the observed effect heterogeneity among studies. CONCLUSIONS In this study, CDA showed comparable or potentially greater success in overall and neurological outcomes, along with a lower incidence of adjacent level degeneration and reoperation rates but longer operative times.

Abstract Little is known about risk factors for central nervous system (CNS) relapse in mature T-cell and natural killer cell neoplasms (MTNKNs). We aimed to describe the clinical epidemiology of CNS relapse in patients with MTNKN and developed the CNS relapse In T-cell lymphoma Index (CITI) to predict patients at the highest risk of CNS relapse. We reviewed data from 135 patients with MTNKN and CNS relapse from 19 North American institutions. After exclusion of leukemic and most cutaneous forms of MTNKNs, patients were pooled with non-CNS relapse control patients from a single institution to create a CNS relapse–enriched training set. Using a complete case analysis (n = 182), including 91 with CNS relapse, we applied a least absolute shrinkage and selection operator Cox regression model to select weighted clinicopathologic variables for the CITI score, which we validated in an external cohort from the Swedish Lymphoma Registry (n = 566). CNS relapse was most frequently observed in patients with peripheral T-cell lymphoma, not otherwise specified (25%). Median time to CNS relapse and median overall survival after CNS relapse were 8.0 and 4.7 months, respectively. We calculated unique CITI risk scores for individual training set patients and stratified them into risk terciles. Validation set patients with low-risk (n = 158) and high-risk (n = 188) CITI scores had a 10-year cumulative risk of CNS relapse of 2.2% and 13.4%, respectively (hazard ratio, 5.24; 95% confidence interval, 1.50-18.26; P = .018). We developed an open-access web-based CITI calculator (https://redcap.link/citicalc) to provide an easy tool for clinical practice. The CITI score is a validated model to predict patients with MTNKN at the highest risk of developing CNS relapse.