Does Obesity Correlate with Postoperative Complications After Elective Posterior Cervical Spine Fusion?

Background: 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 has reported the influence of obesity in thoracolumbar surgery; however, the impact of obesity on postoperative complications after posterior cervical fusion (PCF) is unknown.

Methods: Consecutive patients who underwent cervical laminectomy and multi-level instrumented fusion for degenerative spinal conditions at an academic tertiary care hospital between 2012 and 2019 were evaluated. Patients were categorized into groups with a BMI ≥30.0 kg/m. The modified Japanese Orthopedic Association (mJOA) score, Nurick grading, complications, and postoperative radiographic factors were analyzed. 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 nonobese (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 vs. 38.1 mm, P = 0.04). The intraoperative estimated blood loss was higher among obese patients (561.1 vs. 391.2 mL, P < 0.001). There was no significant difference in absolute scores for neurologic outcomes and radiographic alignment at 12 months after surgery. However, obese patients had significantly more complications than nonobese patients 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 corroborate that PCF surgery provides significant improvement in neurologic and radiographic outcomes at 12 months after surgery for degenerative cervical spinal disorders. Obesity is a factor to consider in the pre-operative risk assessment.