# The impact of body mass and posterior adiposity indices in robotic adrenalectomy

## TL;DR

This study found that higher body mass index increases operation time for transabdominal robotic adrenalectomy but does not affect retroperitoneoscopic approaches.

## Contribution

The study is the first to evaluate the impact of BMI and PAI on robotic adrenalectomy outcomes across both transabdominal and retroperitoneoscopic approaches.

## Key findings

- Higher BMI correlates with longer operative time in transabdominal robotic adrenalectomy.
- BMI ≥25 is associated with longer length of stay but not increased complications.
- Posterior Adiposity Index does not predict operative time in retroperitoneoscopic robotic adrenalectomy.

## Abstract

Robotic adrenalectomy is performed via transabdominal (TA) or retroperitoneoscopic (RP) approaches, but the impact of body mass index (BMI) on robotic adrenalectomy outcomes in either approach is unclear. Posterior Adiposity Index (PAI), predictive of operative time in RP adrenalectomy, remains unevaluated with the robotic platform. This study assessed the impact of patient BMI and PAI on surgical outcomes in patients undergoing either TA or RP robotic adrenalectomy.

This was a single-institution retrospective cohort study of adult patients who underwent robotic adrenalectomy from 5/1/2018 to 6/17/2024. Patients were analyzed by approach and BMI. The primary outcome was operative time. Secondary outcomes included estimated blood loss (EBL), length of stay (LOS), and complications within 30 days. The correlation of operative time to PAI, BMI, and patient characteristics was assessed.

149 patients (age 55 yrs. [IQR:42,66], 70% female) underwent 98 TA and 51 RP robotic adrenalectomies. Patients who underwent TA robotic adrenalectomies had larger nodules, higher BMI, and greater EBL; operative time, LOS, and complications were similar. Patients with elevated BMI (BMI ≥ 25) had similar preoperative characteristics to those with normal BMI (BMI < 25); they had longer operative times (129 min [107, 156] vs. 118 [90, 134], p = 0.045) and LOS (1 [1,1] vs 1 [1,1] p = 0.015) including two patients with 8-day LOS, but similar EBL (5 [5,10] vs. 10 [5,23], p = 0.828) and complication rates (15% vs 5%, p = 0.477). Among TA, but not RP, patients, BMI weakly correlated with operative time (\documentclass[12pt]{minimal}
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\begin{document}$$\rho$$\end{document}ρ = 0.320, p < 0.005). PAI did not correlate with operative time.

This retrospective cohort study evaluating the impact of BMI and PAI on surgical outcomes in patients undergoing robotic adrenalectomy demonstrated that while elevated BMI (BMI ≥ 25) appears to prolong TA robotic adrenalectomy, PAI is not predictive of operative time in RP robotic adrenalectomy.

The online version contains supplementary material available at 10.1007/s00464-025-12416-7.