title: Incidence of perinephric hematoma after percutaneous nephrolithotomy.
abstract: OBJECTIVE
  To identify the incidence of, risk factors for, and subsequent complications of perinephric hematomas after percutaneous nephrolithotomy.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Urology, Sharp Community Medical Group, La Jolla, California 92037, USA. rchichakli@yahoo.com
authors.forename: Ramsey
authors.initials: R
authors.lastname: Chichakli
authors.forename: Rebecca
authors.initials: R
authors.lastname: Krause
authors.forename: Bryan
authors.initials: B
authors.lastname: Voelzke
authors.forename: Thomas
authors.initials: T
authors.lastname: Turk
mesh_terms: D006406:Hematoma / Q000453:epidemiology* / Q000209:etiology* / Q000473:pathology; D006801:Humans; D015994:Incidence; D007430:Intraoperative Care; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000009:adverse effects*; D011182:Postoperative Care; D011183:Postoperative Complications; D011300:Preoperative Care; D014481:United States / Q000453:epidemiology