The Association of Preoperative Bone Mineral Density and Outcomes After Anterior Cervical Discectomy and Fusion A Systematic Review

Study Design: This is a systematic review. Objective: To evaluate anterior cervical discectomy and fusion (ACDF) outcomes and complications as a function of preoperative bone mineral density (BMD). Summary of Background Data: Preoperative BMD optimization is commonly initiated before lumbar spinal fusion, but the effects of BMD on ACDF are less known. Consequently, it remains unclear whether preoperative BMD optimization is recommended before ACDF. Methods: This systematic review included relevant clinical articles using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched PubMed, Web of Science, SCOPUS, and MEDLINE from database inception until October 1, 2023. Eligible studies included those evaluating low BMD and outcomes after ACDF. All articles were graded using the Methodological Index for Non-Randomized Studies (MINORS) scale and Critical Appraisal Skills Programme (CASP) assessment tools. Results: The initial retrieval yielded 4271 articles for which 4 articles with 671 patients were included in the final analysis. The mean patient age was 56.4 +/- 3.9 years, and 331 patients (49.3%) were female. A total of 265 (39.5%) patients had low BMD (T score<-1.0) before ACDF. Preoperative low BMD was associated with cage subsidence in single-level ACDF (odds ratio (OR) 2.57; P=0.063; 95% Confidence Interval (CI): 0.95-6.95), but this result did not reach statistical significance. Osteoporosis (T score<-2.5) was associated with the development of adjacent segment disease following ACDF (OR 4.41; P<0.01; 95% CI: 1.98-9.83). Low pre-operative BMD was associated with reoperation within 2 years (P<.05) and strongly associated with pseudarthrosis (OR: 11.01; P=0.002; 95% CI 2.4-49.9). Conclusions: Patients with low BMD who undergo ACDF have higher rates of subsidence, adjacent segment disease, and pseudarthrosis than those with normal BMD. Given the individual and system-wide burdens associated with these complications, some patients may benefit from preoperative BMD screening and optimization before undergoing ACDF.