Considering the Effects of Age and Patient Factors on Subsidence and Implant Selection in Anterior Cervical Discectomy and Fusion: A Retrospective Cohort Study of 261 Patients.

Study design: Retrospective cohort study.

Objective: The purpose of this study is to assess the relative safety and efficacy of anterior cervical discectomy and fusion (ACDF) procedures and evaluate factors of concern among these patients. We hypothesized that patient age would be predictive of subsidence and all-cause revision.

Summary of background data: ACDF improves cervical alignment and patient outcomes. Although ACDF has a long record of safety and efficacy, revisions remain commonplace, particularly in multilevel fusions. Surgeons and patients would benefit from a greater ability to stratify patients and techniques preoperatively to reduce complications and reoperations.

Patients and methods: A retrospective chart review, over 10 years, of all patients over the age of 18 with neck pain and radiculopathy treated with ACDF, at operative levels C3-C7, was performed. Patients must have immediate postoperative and 6-month follow-up imaging. Exclusion criteria were operative levels C7-T1, trauma, infection, pathology, and a history of previous cervical spine surgery.

Results: In total, 261 patients were included in the final analysis. Radiographically, when compared with white patients, black patients had lower rates of fusion (P<0.001) and greater rates of pseudarthrosis (P=0.013) at 6-month follow-up. The use of titanium cages was significantly predictive of reduced subsidence when compared with the allograft (P=0.029). Greater age was associated with reduced rates of subsidence (P=0.036). When adjusted for race, BMI, and sex, initial height and age were not predictive of revision. Polyetheretherketone (PEEK) implants saw significantly greater rates of revision (P=0.009).

Conclusions: When adjusted for spacer material and number of fused levels, age is not independently predictive of pseudarthrosis, revision, or change in segmental height. Regardless of loss of segmental height, the choice of implant material may not significantly affect reoperation. Differences in rates of fusion and pseudarthrosis in black patients may be temporary; however, surgeons should consider careful monitoring of these patients to avoid unnecessary revisions.