Association Between the Renal Nephrometry Score and Perioperative Outcomes Following Laparoscopic Partial Nephrectomy: A Retrospective Study

BackgroundLaparoscopic partial nephrectomy is an established surgical approach for localized renal tumors, providing oncological control while preserving renal function.However, anatomical tumor complexity may influence surgical difficulty and perioperative outcomes.The Radius, Exophytic/Endophytic properties, Nearness to the collecting system or sinus, Anterior/Posterior location, and Location relative to the polar lines (R.E.N.A.L.) nephrometry score provides a standardized assessment of renal tumor complexity.This study aimed to evaluate the association between R.E.N.A.L. nephrometry score complexity and perioperative outcomes in patients undergoing laparoscopic partial nephrectomy. MethodsWe conducted a retrospective observational study including 77 patients who underwent laparoscopic partial nephrectomy for suspected renal tumors at Mohammed V Military Teaching Hospital in Rabat, Morocco, between January 2021 and March 2025.Patients were stratified into three groups according to their R.E.N.A.L. nephrometry scores: low (4-6), moderate (7-9), and high (10-12) complexity.Perioperative outcomes, including warm ischemia time, estimated blood loss, conversion to radical nephrectomy, positive surgical margins, and postoperative complications, were compared across the three groups. ResultsThe median patient age was 49 years, and the median tumor size was 4.18 cm.Tumors were classified as low complexity in 36 patients (46.8%), moderate complexity in 26 (33.8%), and high complexity in 15 (19.5%).Median warm ischemia time increased significantly with anatomical complexity, from 15 minutes in the lowcomplexity group to 25 and 28 minutes in the moderate-and high-complexity groups, respectively (p < 0.001).Conversion to radical nephrectomy was significantly associated with increasing tumor complexity, occurring in 2.8%, 7.7%, and 33.3% of patients, respectively (p = 0.010).Positive surgical margins were observed in four of the 69 patients who underwent completed laparoscopic partial nephrectomy (5.8%), with rates of 0%, 8.3%, and 20.0% across the three complexity groups, respectively (p = 0.035).No statistically significant associations were observed between tumor complexity and estimated blood loss (p = 0.33) or postoperative complications (p = 0.321). ConclusionsHigher R.E.N.A.L. nephrometry scores were significantly associated with prolonged warm ischemia time, increased intraoperative conversion to radical nephrectomy, and higher positive surgical margin rates among completed laparoscopic partial nephrectomies.No statistically significant associations were observed with estimated blood loss or postoperative complications.These findings support the potential utility of the R.E.N.A.L. score in preoperative surgical planning, although larger studies with multivariable analyses are warranted.