The Impact of Obesity on Postoperative Opioid Consumption after a Single-Level Anterior Lumbar Interbody Fusion

Presented at SMISS Annual Forum 2014
By Abbas Naqvi BS
With Kern Singh MD, Sreeharsha V. Nandyala BA, Alejandro Marquez-Lara MD, Islam Elboghdady , Eric Sundberg MD, Hamid Hassanzadeh MD, Anton Jorgensen MD, Sriram Sankaranarayanan MD,

Disclosures: Abbas Naqvi BS None Kern Singh MD A; CSRS Resident Grant. B; DePuy, Zimmer, Stryker, CSRS, ISASS, AAOS, SRS, Vertebral Column - ISASS. D; Avaz Surgical, LLC, Vital 5, LLC. F; Zimmer, Stryker, Pioneer, Lippincott Williams & Wilkins, Th, Sreeharsha Nandyala BA None, Alejandro Marquez-Lara MD None, Islam Elboghdady None, Eric Sundberg MD None, Hamid Hassanzadeh MD None, Anton Jorgensen MD None, Sriram Sankaranarayanan MD None,

Introduction:
There is perception bias regarding the narcotic requirements to achieve appropriate postoperative pain relief in obese patients. Understanding the differences in narcotic consumption based upon the patient’s body mass index (BMI) is important to reduce the risk of toxicity and side effects that may result from weight-based narcotic dosing.

Aims/Objectives:
To evaluate the differences in opioid utilization between obese and non-obese patients in the setting of a single-level anterior lumbar interbody fusion (ALIF).

Methods:
A cohort of 58 patients who underwent a primary single-level ALIF procedure for degenerative spinal pathology was retrospectively analyzed. Patients were stratified based upon their body mass index (Obesity: BMI>30.0Kg/m2) and assessed with regards to patient demographics, comorbidity burden, smoking status, intraoperative parameters, in-hospital outcomes, and cumulative and daily (postoperative day (POD) oral morphine equivalent (OME) doses received. Statistical analysis was performed with a chi-squared test for categorical variables and Student-Test for continuous variables. OME means were compared utilizing non-parametric analysis to adjust for skewedness. A p-value of <0.05 denoted statistical significance.

Results:
Of the 58 ALIF procedures included in this analysis 26 (44.8%) were performed on obese patients (BMI: 35.3±4.6 Kg/m2) and 32 (55.2%) on non-obese patients (BMI: 24.5±2.6 Kg/m2). There were no significant differences in patient demographics, comorbidity burden, procedural times, rates of peri-operative complications, and length of hospitalization between cohorts. Daily OME dose did not significantly differ between discharge days regardless of patient BMI. Similarly, the cumulative narcotic consumption was comparable between obese and non-obese patients on all discharge days. (POD 1: 53.1±20.9 vs 28.3±13.1, p=0.26; POD 2: 70.7±35.0 vs 119.8±222.7, p=0.94; POD 3: 169.5±205.8 vs 122.3±35.6, p=0.95).

Conclusions:
This analysis demonstrated that obese patients demand comparable narcotic amounts as non-obese patients following a single-level ALIF. Weight-based opioid dosing for obese patients may not be warranted in the immediate postoperative period to achieve appropriate pain control after anterior lumbar arthrodesis.