Perirenal fat thickness is a powerful predictor for surgical outcomes of transperitoneal laparoscopic adrenalectomy

Objectives: Laparoscopic adrenalectomy has been the gold standard surgical procedure. However, the adaptation criteria for malignant tumors and predictors of perioperative outcomes are not well defined. Therefore, this study tried to identify valid predictors for perioperative outcomes of laparoscopic adrenalectomy and consider the adaptation criteria. Methods: We retrospectively reviewed the preoperative and perioperative data of 216 patients who underwent transperitoneal laparoscopic adrenalectomy in our hospital. Preoperative factors associated with perioperative outcomes were analyzed using multiple regression analysis. Results: Among 216 patients, 165 (76.4%), 26 (12.0%), and 25 (11.6%) were suspected of having benign tumors, pheochromocytoma, and malignant tumors, respectively. Median tumor size was 25.0 mm (interquartile range 18.0-35.0); median perirenal fat thickness was 9.2 mm (interquartile range 4.9-15.6) on preoperative computed tomography scans. The median operative time was 145.5 min (interquartile range 117.5-184.0) and the median estimated blood loss was 0.0 mL (interquartile range 0.0-27.3). Perirenal fat thickness (p < 0.001), tumor size (p < 0.001), and malignant tumors (p = 0.020) were associated with operative time, and perirenal fat thickness (p = 0.038) and malignant tumors (p = 0.002) were associated with estimated blood loss. Conclusions: Perirenal fat thickness, tumor size, and malignant tumors are valid predictors of the surgical outcomes of transperitoneal laparoscopic adrenalectomy. As only perirenal fat thickness is associated with both surgical outcomes except for malignant tumors, it is a powerful predictor. Transperitoneal laparoscopic adrenalectomy for large malignant adrenal tumors with thick perirenal fat should be performed with caution.