Obesity does not impact clinical outcome but affects cervical sagittal alignment and adjacent segment degeneration in short term follow-up after an anterior cervical decompression and fusion

Obesity increases complications and cost following spine surgery. However, the impact on sagittal alignment and adjacent segment degeneration (ASD) after anterior cervical decompression and fusion is less understood. To compare clinical and radiographic outcomes after anterior cervical decompression and fusion between obese and nonobese patients. Retrospective cohort study. In all, 467 patients that underwent an anterior cervical decompression and fusion procedure from January 2008 through December 2015 were assessed. Surgery indications were radiculopathy, myelopathy, or myeloradiculopathy that had failed nonoperative treatments. Exclusion criteria included patients who had postoperative follow-up less than 6 months. Of 467 patients originally identified, 399 fulfilled the inclusion and exclusion criteria. The following patient-reported outcomes were obtained: Neck Disability Index and Visual Analog Scale scores for the neck and arm pain. Radiographic assessments included: C2–C7 lordosis, T1 angle, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, proximal and distal adjacent segment lordosis, ASD, and presence of fusion. Plain radiographs were performed preoperatively, immediately postoperatively, and final follow-up. Demographic information was collected on all patients. Baseline patient characteristics were compared using chi-squared analysis and independent sample t tests for categorical and continuous data, respectively. For analysis, patients were divided into 4 groups based on obesity stratification as defined by Center for Disease Control: body mass index (BMI)