Urinary fistulae after partial nephrectomy.

OBJECTIVE: To report the risk factors and natural history of urinary fistula (UF) after partial nephrectomy (PN), as their incidence has been reported to be 3-6% in large series of PN but there are few reports of the risk factors associated with the development of UF after PN, and the natural history of UF in a large group of patients. PATIENTS AND METHODS: This was a retrospective review of 1118 PN at one tertiary-care institution. Most patients had a drain placed in the perinephric space after surgery. Fifty-two patients were identified as having a UF if they had persistent flank drainage for >14 days after surgery, or presented with evidence of a UF after the drain had been removed. Risk factors for development and the course of the UF are reported.
RESULTS: Fifty-two patients developed a UF after PN (4.4%, 95% confidence interval, CI, 3.5-6.1%) The rate of a persistent urine leak (defined as drain fluid consistent with urine for >2 weeks after surgery) was 4.0 (95% CI 2.9-5.3)%. The overall rate of delayed UF presentation was only 0.4 (0.09-0.9)%. Patients who developed a UF had larger tumours (3.5 vs 2.6  cm, P= 0.03), a higher estimated blood loss (400 vs 300  mL, P < 0.001), and longer ischaemia time (50 vs 39  min, P < 0.001) than patients who did not develop a UF. Differences in tumour histology, laterality, multifocality, type of surgery (laparoscopic vs open), and intraoperative collecting system entry were not statistically different in patients who did or did not develop a UF. Patients with tumours of >2.5  cm were twice as likely to develop a UF than patients with tumours of <2.5  cm (P= 0.02). Most patients were managed conservatively with a percutaneous drain until the UF resolved, if they were asymptomatic. Overall, in 36 patients (69%) the fistula resolved with no intervention, while 16 (31%) required intervention. Stenting was the commonest intervention (15%). No patient required re-operative open surgery.
CONCLUSION: The rate of development of UF after PN is low. Tumour size, blood loss and ischaemia time were all associated with the development of a UF. In most patients with a urine leak immediately after surgery the UF will resolve with no intervention, and can be managed conservatively with patience, in the absence of clinical symptoms.