The influence of obesity on patient reported outcome scores and complication rates following single-level microdiscectomy.

Abstract

Purpose: In recent clinical practice, a rise in patients with multiple comorbidities including obesity has being identified among those being considered for elective spinal surgery. Literature shows conflicting results regarding the influence of obesity on patient-reported outcomes following single-level microdiscectomy. The aim of the study is to assess if Body Mass Index (BMI) is an appropriate determining factor of Patient-Reported Outcome Scores (PROMs) and complication rates following single-level microdiscectomy, and to determine if a weight reduction from obese to overweight could reduce complication rates and improve PROMs.

Material and methods: This retrospective study was conducted for a randomised sample of single-level microdiscectomy procedures completed between January 2012 to May 2023 at the University Hospitals Plymouth neurosurgery department. Ninety patients were randomly selected into three groups of 30 based on their BMI. Out of the 90 patients, 63 were eligible, having had a complete set of data, 36.51% were classed as obese (BMI $\ge$ 30), 41.27% as overweight (BMI 25-29) and 22.22% as normal-BMI (BMI $\le$ 24.9).

Results: Patients classed as having an obese BMI showed the greatest improvement of their PROMs, with their Visual Analogue Score (VAS) for leg pain showing a mean improvement of 6.263 out of 10. Importantly, the pre-operative mean leg pain was higher for obese patients than overweight and normal-BMI ones. Likewise, the obese patients' Oswestry Disability Index (ODI) showed a mean improvement of 29.091%. In regard to complication rates, obese patients experienced the highest complication rate, with 17.39% of obese patients experiencing complications compared to 7.69% and 7.13% of overweight and normal-BMI patients respectively.

Conclusion: The increased rate of complications among obese patients underlines the importance of weight reduction. The findings also indicate that BMI is not the sole determinant for better surgical outcomes, as obese patients showed the greatest improvements in their PROM scores.