Effectiveness of Mayo Adhesive Probability Score in Prediction of Surgical Complexity and Perioperative Outcomes during Laparoscopic Transperitoneal Simple Nephrectomy: A Prospective Observational Study

Introduction: The Mayo Adhesive Probability (MAP) score is a preoperative Computed Tomography (CT)-based scoring system developed to predict the presence of Adherent Perinephric Fat (APF), a known contributor to increased surgical difficulty. While extensively studied in partial nephrectomy, its application in Laparoscopic Transperitoneal Simple Nephrectomy (LTSN) remains unvalidated. Aim: To evaluate the effectiveness of the MAP score in predicting surgical difficulty and perioperative outcomes in patients undergoing LTSN. Materials and Methods: The present prospective observational study was conducted at the Department of Urology, IPGME&R ,Kolkata, West Bengal, India, from July 2024 to March 2025. Fifty patients undergoing LTSN for benign non-functioning kidneys were enrolled. Preoperative MAP scores were calculated from CT imaging. Patients were categorised into three groups: Low (0-1), Moderate (2-3), and High (4-5) MAP scores. Surgical difficulty was graded using a novel composite score based on intraoperative and postoperative parameters. Statistical analysis included the Kruskal-Wallis test and Spearman’s rank correlation using Statistical Package for Social Sciences (SPSS) v25, considering the ordinal nature of MAP scores and non-parametric data distribution. and a p-value <0.05 was considered statistically significant. Results: A total of 50 patients were included in the study, with a mean age of 53.2±10.6 years and a mean Body Mass Index (BMI) of 26.1±3.4 kg/m². Based on MAP score stratification, 12 (24.0%) patients were categorised into the Low MAP group (0-1), 23 (46.0%) patients into the moderate MAP group (2-3), and 15 (30.0%) patients into the high MAP group. A statistically significant association was observed between MAP scores and all intraoperative and postoperative difficulty markers. The high MAP group had the longest operative time (170.53±30.1 min), greatest blood loss (569.27±107.02 mL), maximum haemoglobin decline (2.05±0.48%), highest complication rate (73.3%) and prolonged hospital stay (7.53±1.36 days). The Low MAP group showed favourable metrics across all parameters (operative time 107.5±22.13 min, blood loss 258.25±37.68 mL, complications in 16.7%, and hospital stay 3.92±1.08 days). Kruskal-Wallis test confirmed statistical significance (p<0.001). Conclusion: The MAP score is a validated, reliable preoperative tool for predicting surgical difficulty in LTSN. High MAP scores are significantly associated with increased surgical complexity, prolonged operative time, blood loss, and postoperative complications.