title: Routine postoperative imaging is important after ureteroscopic stone manipulation.
abstract: OBJECTIVE
  Improved fiber optics and advanced intracorporeal lithotripsy devices have significantly decreased the incidence of complications during ureteroscopic procedures. Despite recent reports suggesting that radiographic imaging may not be necessary in all individuals after routine ureteroscopy silent obstruction may develop in some, ultimately resulting in renal damage. We determined the incidence of postoperative silent obstruction at our institution and assessed the need for routine functional radiographic studies after ureteroscopy.
  
  
  METHODS
  We retrospectively reviewed the charts of 320 patients who underwent a total of 459 ureteroscopic procedures for renal or ureteral calculi in a 3-year period. Complete followup with imaging was available for 241 patients (75%). Average patient age was 47.2 years. The variables of interest reviewed included preoperative pain, preoperative obstruction, targeted calculous site, stone-free rate, postoperative pain and postoperative obstruction. Mean followup was 5.4 months (range 2 to 43).
  
  
  RESULTS
  A total of 241 patients with complete followup were identified in this analysis. Preoperative pain was present in 202 patients (84%) and 168 (70%) had preoperative obstruction. Overall targeted calculous clearance was successful in 73% of the patients and an additional 15.8% had residual fragments less than 4 mm. The renal, proximal or mid and distal ureteral stone-free rate was 32.1%, 81.9% and 90.5%, while in an additional 46.4%, 6.3% and 6.7% of cases, respectively, residual fragments were less than 4 mm. Of the 241 patients 30 (12.3%) had obstruction postoperatively due to residual stone in 25 (83.3%), stricture in 3 (10%), edema of the ureteral orifice in 1 (3.3%) and a retained encrusted stent in 1 (3.3%). Postoperatively obstruction correlated with postoperative pain in 23 of the 30 patients (76.7%). Pain was present postoperatively in 30 of the 211 patients (14%) without evidence of ureteral obstruction postoperatively. However, silent obstruction developed in 7 patients (23.3%) or 2.9% of the total cohort. All 7 patients underwent secondary ureteroscopy to alleviate obstruction. A single patient ultimately received chronic hemodialysis for renal failure, 1 was lost to followup and in 5 there was documented successful resolution of the cause of obstruction.
  
  
  CONCLUSIONS
  Our analysis suggests that silent obstruction remains a potentially significant complication after stone management. Relying on postoperative pain to determine the necessity of postoperative imaging places patients at risk for progressive renal failure due to unrecognized obstruction. Therefore, we recommend that imaging of the collecting system should be performed by excretory urography, spiral computerized tomography or ultrasound within 3 months after routine ureteroscopic stone treatment to avoid the potential complications of unrecognized ureteral obstruction.
authors.affiliation: Comprehensive Kidney Stone Center, Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Alon Z
authors.initials: AZ
authors.lastname: Weizer
authors.forename: Brian K
authors.initials: BK
authors.lastname: Auge
authors.forename: Ari D
authors.initials: AD
authors.lastname: Silverstein
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Delvecchio
authors.forename: Ricardo M
authors.initials: RM
authors.lastname: Brizuela
authors.forename: Philipp
authors.initials: P
authors.lastname: Dahm
authors.forename: Paul K
authors.initials: PK
authors.lastname: Pietrow
authors.forename: Bertram R
authors.initials: BR
authors.lastname: Lewis
authors.forename: David M
authors.initials: DM
authors.lastname: Albala
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Preminger
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy; D008297:Male; D008875:Middle Aged; D019233:Retreatment; D015607:Stents; D014057:Tomography, X-Ray Computed; D014514:Ureteral Calculi / Q000000981:diagnostic imaging / Q000628:therapy*; D014517:Ureteral Obstruction / Q000000981:diagnostic imaging* / Q000209:etiology / Q000628:therapy; D018666:Ureteroscopy; D014567:Urography