Risk factors and management of urine leaks after partial nephrectomy. 
As nephron sparing surgery is used more frequently for select renal tumors, the incidence of urine leaks will likely increase.  To our knowledge the risk factors of and management strategies for urine leaks have not been studied.  We report our experience with the risk factors of and management for urine leaks after open and laparoscopic partial nephrectomy.  We retrospectively reviewed the records of 127 consecutive patients who underwent partial nephrectomy between 2001 and 2007, including 70 with open and 57 with laparoscopic partial nephrectomy, as performed by 3 surgeons.  Urine leak was defined as drain output consistent with urine greater than 48 hours after laparoscopic partial nephrectomy.  Of the patients 21 experienced a urine leak after partial nephrectomy, including 13.3% overall, and 10.5% after laparoscopic and 18.5% after open partial nephrectomy.  Patients with a urine leak had significantly greater tumor size (3.2 vs 2.4 cm, p <0.044), endophytic locations (57% vs 19%, p <0.00027) and repair of collecting system defects during partial nephrectomy (95% vs 56%, p <0.00072).  There was no association with the number of tumors removed, estimated blood loss, ischemia time, body mass index, age or other surgical complications.  The median duration of urine leak was 20 days.  While most urine leaks resolved with prolonged drainage, 38% of cases required further intervention.  Patient age at surgery was the only factor that correlated with prolonged (greater than 30 days) urine leak.  Urine leak is a complication unique to partial nephrectomy that is more commonly noted when a larger endophytic mass involves the renal collecting system.  Most leaks resolve with prolonged drainage or replacement of a ureteral stent.