Impact of Severe Obesity on Outcomes in Single-Level Anterior Cervical Discectomy and Fusion (ACDF): A Large-Scale Comparative Study

Background: Anterior cervical discectomy and fusion (ACDF) is a common procedure for cervical radiculopathy and myelopathy. Severe obesity (BMI ≥ 40 or BMI ≥ 35 with comorbidities) is associated with increased perioperative risks. This study examines the impact of severe obesity on outcomes in patients undergoing single-level ACDF. Methods: Data from the Nationwide Inpatient Sample (2016–2019) were analyzed, including 85,585 patients who underwent single-level ACDF. Patients were classified as severely obese (n = 4935) or non-obese (n = 80,650). Outcomes such as length of stay, complications, and in-hospital mortality were compared using SPSS and MATLAB, with a significance level of p < 0.05. Results: Severely obese patients were younger (54 vs. 55.7 years, p < 0.001) and had more comorbidities like type 2 diabetes (38% vs. 17.8%, p < 0.001) and obstructive sleep apnea (31.1% vs. 9.5%, p < 0.001). They experienced longer hospital stays (1.92 vs. 1.65 days, p < 0.001) but similar in-hospital mortality (0.1%, p = 0.506). Severe obesity was linked to higher odds of complications, including increased risks of dehiscence (OR 8.2), respiratory failure (OR 6.5), myocardial infarction (OR 5.5), Horner syndrome (OR 4.7), pulmonary edema (OR 4.5), and dural tears (OR 4.1). Risks of acute kidney injury, pulmonary embolism, and dysphonia were also elevated in severely obese patients. Conclusion: Severe obesity is associated with higher complication rates and longer hospital stays following ACDF. Tailored perioperative management is essential to mitigate these risks and improve outcomes in this high-risk population.