Does Increasing Body Mass Index Correlate with Adverse Outcomes Following Posterior Cervical Fusions?

Obesity has been shown to be associated with higher rates of complications after lumbar spine surgery. However, the evidence regarding the impact of body mass index (BMI) on outcomes following posterior cervical fusions (PCFs) remains limited.

The 2012-2017 American College of Surgeons National Surgical Quality Improvement Program database was queried using Current Procedural Terminology code 22600 to identify PCFs. Patients undergoing anterior cervical spine surgery and surgery for deformity, malignancy, or infection were excluded. Patients with missing data with regard to weight, height, and 30-day outcomes were excluded. BMI (kg/m²) was categorized into 4 groups: 1) <25.0, 2) 25.0-29.9, 3) 30.0-34.9, and 4) ≥35.0. Multivariate regression analyses were constructed to assess independent impact of BMI on 30-day outcomes while controlling for baseline clinical characteristics.

Of 2786 patients with PCFs, 710 (25.5%) had BMI <25.0, 919 (33.0%) had BMI between 25.0 and 29.9, 655 (23.5%) had BMI between 30.0 and 34.9, and 502 (18.0%) had BMI ≥35.0. Following adjustment for baseline demographics and clinical characteristics, increased BMI was not associated with a higher risk of any adverse events, severe adverse events, minor adverse events, bleeding requiring transfusion, or readmissions within 30 days of surgery. BMI ≥35.0 versus BMI <25.0 was associated only with a higher risk of deep surgical site infections (odds ratio 4.61; P = 0.009).

With the exception of a higher rate of deep surgical site infections seen in obese patients, increased BMI does not seem to have a major impact on 30-day outcomes following PCFs.