DOI: 10.1097/bpo.0000000000003297 ISSN: 0271-6798

The Effect of Liposomal Bupivacaine and Obesity on Postoperative Opioid Consumption in Children With Scoliosis

Emmanuel Ogu, Judy-Mae Lima, David Thornberg, Christopher McLeod, Amy McIntosh, Brandon Ramo, Chan-hee Jo, Jaysson T. Brooks

Background:

Liposomal bupivacaine (LB) is increasingly used in multimodal pain management protocols for the treatment of adolescent idiopathic scoliosis (AIS) with instrumented posterior spinal fusion (PSF), yet its efficacy in obese pediatric populations remains unclear. Obesity is associated with increased pain burden, potentially diminishing LB’s analgesic benefits. Therefore, the purpose of this study is to evaluate postoperative opioid consumption in AIS patients treated with LB.

Methods:

We conducted a retrospective cohort study of AIS patients aged 10 to 19 years who underwent PSF with intraoperative LB between 2020 and 2022 at a single institution. Patients were stratified by BMI percentile (underweight, healthy weight, overweight, and obese). Postoperative opioid consumption was quantified in morphine equivalents per kilogram (MME/kg) and analyzed for the first 24 hours and total inpatient stay. Pain scores, SRS-30 outcomes, and pain catastrophizing were assessed. Multivariable linear regression with backward selection was used to evaluate predictors of opioid use.

Results:

A total of 190 patients were included. In the first 24 hours, obese patients consumed less MME/kg ( β =−0.08, P =0.0290), but this association lost significance after backward selection. However, obese patients consumed significantly less total inpatient MME/kg than healthy-weight patients ( β =−0.50, P =0.0001), a difference that remained significant after backward selection. Increasing BMI percentile correlated negatively with total inpatient opioid use (ρ=−0.182, P =0.012). Male sex and higher pain scores were consistent predictors of early postoperative opioid use. There were no differences in pain scores, SRS-30 scores, or pain catastrophizing across BMI groups.

Conclusions:

Contrary to our hypothesis, obesity was associated with significantly lower postoperative opioid use over the total inpatient stay following PSF with LB. These findings suggest a possible opioid-sparing effect of LB in obese pediatric patients, potentially due to altered drug pharmacokinetics. Further prospective studies are needed to investigate the mechanisms underlying this effect.

Level of Evidence:

Level III—retrospective cohort study.

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