LAUSR

INTRODUCTION With the increasing prevalence of obesity, there is a need to understand the impact of body mass index (BMI) on spine surgery outcomes. Previous literature reported the influence of obesity in thoracolumbar surgery; however, the effect of obesity on postoperative morbidity following posterior cervical fusion (PCF) is unknown. METHODS Consecutive patients who underwent decompressive cervical laminectomy and bicortical lateral mass screw-rod arthrodesis for degeneration at an academic tertiary care hospital between 2012-2019 were evaluated. Patients were categorized into groups with a BMI ≥30.0 kg/m2. The modified Japanese Orthopedic Association score (mJOA), Nurick grading, complications, and post-operative radiographic factors were used. Correlations between postoperative outcomes and obesity were calculated at baseline and 1-year. RESULTS A total of 275 patients were included, with 80 obese (29.1%) and 195 non-obese (70.9%) patients. At baseline, obesity was associated with worse myelopathy (mJOA score: 10.2 vs 13.1, p=0.04 and Nurick grading: 3.2 vs 1.1, p=0.05), and abnormal cervical radiographic alignment (C2-7 sagittal vertical axis: 43.9 mm vs 38.1 mm, p=0.04). The intra-operative estimated blood loss was higher among obese patients (561.1ml vs 391.2ml, p<0.001). There was no significant difference in absolute scores for neurological outcomes, and radiographic alignment at 12-months following surgery. However, obese patients had significantly more complications compared to non-obese group in terms of mechanical failure (6.3% vs 0.5%, p=0.05) and wound infection (8.7% vs 0.0%, p=0.04). CONCLUSIONS Our results corroborated that PCF surgery provided significant improvement in neurological and radiographic outcomes at 12-months after surgery for degenerative cervical spine disease.