Surgical Risk and Patient-Reported Outcomes in 3- and 4-Level Anterior Cervical Discectomy and Fusion: A Comparative Study

Abstract

Introduction: The existing literature on anterior cervical diskectomy and fusion (ACDF) predominantly focuses on 1- and 2-level procedures, leaving limited data comparing outcomes of 3- versus 4-level standalone ACDFs. Thus, the aim of this study was to compare surgical outcomes and patient-reported outcome measures (PROMs) of 3- versus 4-level ACDF. Methods: Patients who underwent 3- or 4-level ACDF within a single academic health system (2014 to 2020) were retrospectively identified. Surgical outcomes and PROMs were evaluated, including the 0 to 10 numeric rating scale for neck and arm pain, Short Form-12, Modified Japanese Orthopaedic Association (mJOA), and Neck Disability Index (NDI). Patients were excluded if they did not have complete preoperative or 1-year postoperative mJOA scores, underwent ACDF for tumor/trauma/infection, or had concomitant posterior cervical fusion. Results: A total of 256 patients were included (46 4-level ACDFs). Patients undergoing 4-level ACDF had higher BMI (30.8 vs. 28.9; P = 0.032) and a greater prevalence of myelopathy (45.7% vs. 33.3%; P = 0.018) but were otherwise demographically similar to 3-level ACDF patients. Four-level ACDF patients had a higher dysphagia rate (20% vs. 8.6%; P = 0.033) and a higher 30-day ED visit rate (6.5% vs. 0%; P = 0.005) but similar readmission rates and all other surgical outcomes. Patients with 4-level ACDF had better 6-month NDI scores but worse 1-year mJOA scores. All other PROM comparisons and deltas were similar at all time points. Conclusion: Patients undergoing 4-level ACDF had higher BMI and a greater prevalence of myelopathy than those undergoing 3-level ACDF; 4-level ACDF was associated with a higher rate of dysphagia and early postoperative ED utilization, but not readmissions. The groups otherwise did similarly with respect to surgical outcomes and PROM improvements. These findings suggest that extending fusion from three to four levels was not associated with increased surgical risk or inferior short-term functional or pain outcomes compared with 3-level ACDF.