B. M. Lindeman1,2, A. A. Gawande2, F. D. Moore2, N. L. Cho2, G. M. Doherty2, M. A. Nehs2 1University Of Alabama At Birmingham,Surgery,Birmingham, AL, USA 2Brigham And Women’s Hospital,Surgery,Boston, MA, USA
Introduction:
No objective criteria exist to guide surgeons about which minimally invasive approach (laparoscopic transabdominal [LA] or retroperitoneoscopic [RP]) to adrenalectomy is optimal. We aimed to determine whether anthropometric imaging characteristics could predict optimal adrenalectomy approach based on operative time and estimated blood loss (EBL).
Methods:
A retrospective cohort study was conducted for all adult patients undergoing minimally-invasive adrenalectomy between 2014-2016 (n=113) at one tertiary-care hospital where both LA and RP adrenalectomy are performed. Anthropometric measurements included distances between the skin and Gerota’s fascia at the 12th rib tip (S-GF), the adrenal and upper border of the kidney (A-K), the adrenal and tip of 12th rib (A-R), the 12th rib and top of the iliac crest (R-IC), and perinephric fat thickness (PNF) on CT or MRI. The effect of these characteristics as well as patient BMI, gender, age, tumor size, and diagnosis on operative time and estimated blood loss (EBL) were analyzed independently with Pearson’s correlation or ANOVA, as appropriate. A multivariable linear regression model was also constructed to identify independent predictors of operative time after adjustment.
Results:
Half of patients underwent LA (n=56) while half had an RP approach (n=57). Median age was 57 years; 60% were female. Endocrine disorders were the most common adrenalectomy indication (51%) and mean tumor size was 3.2cm. Only 36% of patients had a BMI <25; 39% had a BMI >30. Patients with a higher BMI were significantly more likely to undergo LA (p=0.03). Increasing lesion size was modestly correlated with longer operative time (r=0.296) independent of operative approach. Bivariate analysis demonstrated that S-GF distance and PNF were moderately correlated with operative time (r=0.464 and 0.494, respectively) for RP procedures. The product of the S-GF and PNF variables was used to generate a Posterior Adiposity Index (PAI), and the PAI demonstrated a strong correlation with operative time for RP procedures (r=0.608). No other demographic or anthropometric variables were associated with increased operative time or EBL on bivariate analyses. Multivariate analysis revealed that larger lesions (p=0.025) and increasing PAI (p=0.019) were associated with longer operative time, with PAI ≥12 conferring the greatest risk (p=0.004).
Conclusion:
Patients undergoing RP adrenalectomy for smaller lesions and with body habitus conferring a PAI <12 had significantly shorter operative times. Surgeons can utilize data from preoperative imaging to calculate the Posterior Adiposity Index to determine whether an RP or LA approach would be optimal.