Intraoperative Surgeon-Performed Ultrasound in Complex Partial Nephrectomy: Insights from Challenging Renal Tumors.

Introduction: Intraoperative ultrasound (IOUS) is increasingly utilized in nephron-sparing surgery for its ability to provide real-time, high-resolution imaging that enhances tumor localization and resection accuracy. Its role becomes particularly important in anatomically complex cases such as endophytic, multifocal, or recurrent renal tumors, as well as in patients with a solitary kidney. Methods: We conducted a retrospective analysis of 152 patients who underwent partial nephrectomy for localized renal tumors between January 2019 and December 2024. Patients were divided into two groups: Group A (n = 24) included patients with a solitary surgical kidney or tumor recurrence; Group B (n = 128) included patients with a contralateral functional kidney. IOUS was used in 31 cases (20%). Demographic, perioperative, and oncological outcomes were compared, with specific attention to the use and impact of IOUS. Results: IOUS was significantly more common in Group A (75%) than in Group B (10%) (p < 0.001), reflecting its preferential use in higher-complexity surgeries. The rate of positive surgical margins was low overall, with no significant difference between the IOUS and non-IOUS groups (3.2% vs. 1.7%; p = 0.54). IOUS was more frequently employed in cases involving medium/high RENAL nephrometry scores and multifocal tumors, contributing to improved intraoperative tumor delineation without increasing complication rates. Conclusions: IOUS enhances surgical precision and supports oncologic safety in both robotic and open partial nephrectomies, particularly in complex scenarios. Its use should be encouraged as a standard adjunct in conservative renal surgery, especially in patients with a solitary kidney, recurrent disease, or multifocal tumors.