The impact of obesity on surgeon ratings and patient-reported outcome measures after degenerative cervical spine disease surgery

Objective: Obesity is a growing public health problem. A considerable number of patients undergoing cervical spine surgery are obese, but the correlation between obesity and surgical outcome is still unclear. In this study, we investigated the impact of body mass index (BMI) on patients' and surgeons' perception of spine surgery outcomes.

Methods: We analyzed a prospectively collected spine surgery registry with patient-reported outcome measures and surgeon ratings. Mixed-effects linear models and linear regression models were applied to investigate the relationship between different World Health Organization obesity classifications and surgical outcome.

Results: A total of 88 patients had surgery for degenerative cervical spine disease, with 97.72% follow-up at 3 months and 94.31% at 6 months postoperatively. Mean BMI was 27.92 ± 7.9 kg/m(2); 28.57% were overweight (BMI 25-29.9), and 31.57% were obese (Class I obesity, BMI 30-34.9). We found a positive correlation between BMI and VAS at 6 months (R = 0.298, P < 0.05) and between BMI and change in Neck Disability Index (R = 0.385, P < 0.01), suggesting that obese patients had less improvement and more pain 6 months postoperatively than nonobese patients. Overweight patients had worse MCS values (R = -0.275, P < 0.05) and obese patients had worse visual analog scale values 6 months after surgery (R = 0.284, P < 0.03). Interestingly, surgeon ratings matched the aforementioned results. Patients with greater BMI had worse surgeon ratings 3 and 6 months postoperatively (R = 0.555, P < 0.05), whereas normal-weight patients had better outcomes when rated from the surgeon's perspective (R = -0.536, P < 0.05).

Conclusion: Obese patients had worse postoperative patient-reported outcome scores and less overall patient-rated improvement compared with nonobese patients. Patients with BMI >25 reported less improvement after surgery both in the patients' and in the surgeons' perspectives.