Perirenal fat stranding on preoperative imaging is associated with a prolonged operative time in pediatric radical...

To evaluate whether preoperative perirenal fat stranding is associated with operative time and outcomes in pediatric radical nephrectomy for primary renal tumors.

We retrospectively reviewed 30 children who underwent open radical nephrectomy at a single institution between 2000 and 2025. Because posterior perirenal fat thickness showed no variability, analyses focused on perirenal fat stranding (none, type 1, and type 2). Primary outcomes were operative time and intraoperative blood loss normalized to body weight. Secondary outcomes were intraoperative complications, tumor spillage, and postoperative complications within 30 days.

Posterior perirenal fat thickness was 0 in all patients. Fat stranding was absent in 13 patients, type 1 in 11, and type 2 in 6. Operative time was longer in the type 2 group than in the other groups (both p < 0.05), whereas blood loss did not differ significantly. Stranding severity was not associated with secondary outcomes or preoperative tumor diameter. In age-adjusted analysis, the association with operative time was attenuated and no longer significant.

Preoperative perirenal fat stranding is associated with prolonged operative time and may not be explained by tumor size alone. However, this association is attenuated after adjustment for age at surgery and should be interpreted cautiously.