Incidence of perinephric hematoma after percutaneous nephrolithotomy

To identify the incidence of, risk factors for, and subsequent complications of perinephric hematomas after percutaneous nephrolithotomy.

We retrospectively analyzed patients who had undergone CT within 5 days of surgery for evidence of perinephric hematomas. Hematoma severity was graded on a 4-point system in which 0 = no blood, 1 = subcapsular blood, 2 = perinephric blood that does not or minimally displaces the kidney, 3 = blood that displaces the kidney > 2 cm, and 4 = blood that extends into the retroperitoneum. Univariate analysis was performed to identify significant preoperative, intraoperative, or postoperative risk factors.

A total of 202 patients underwent percutaneous nephrolithotomy and were imaged with CT within 5 days of surgery. Of these, 140 (69%) were grade 0, 55 (27.2%) had localized bleeding (grades 1 or 2), and 7 (3.5%) had extensive bleeding (grades 3 or 4). Complications developed postoperatively in 13 of the patients in groups 1 to 4, including persistent fever longer than 12 hours after surgery in 8 patients, ileus in 2 patients, transfusion of packed red blood cells in 2 patients, and hydrothorax necessitating a chest tube in 1 patient. No patient had surgical or percutaneous intervention. At 3-month follow-up, no patients had symptoms or needed further imaging. Placement of a ureteral stent at the conclusion of the procedure occurred in a significantly higher number of patients in groups 1 to 4 (P = 0.009). The remaining factors were not significantly different. Subset analysis revealed a significantly greater hemoglobin decline in patients with extensive hematomas, groups 3 and 4, compared with groups 0 to 2 (P = 0.001).

Perinephric hematomas occur in nearly one-third of patients undergoing percutaneous nephrolithotomies but are extensive only 11% of the time. Hematomas are not associated with an increased incidence of clinically relevant complications. There does not appear to be any indication for serial imaging during hospitalization or at 3-month follow-up.