title: Locked Deflection During Flexible Ureteroscopy: Incidence and Elucidation of the Mechanism of an Underreported Complication.
abstract: OBJECTIVE
  Flexible ureteroscopy (URS) is widely implemented with a well-defined safety profile and low complication rates. Although rare, locked deflection of a flexible ureteroscope in the upper tract is a potentially serious complication with poorly understood etiology and is likely underreported.
  
  
  METHODS
  We attempted to capture all cases of locked deflection during URS by performing an anonymous, online computer survey targeting members of the Endourological Society. The Manufacturer and User Facility Device Experience (MAUDE) database and published literature were queried to find additional cases. The indication for URS, method of ureteroscope removal, patient outcomes, incident reporting, and explanations provided by the manufacturer or third party repair service were obtained whenever possible.
  
  
  RESULTS
  In total, 10 cases of locked deflection during flexible URS were identified. Survey responses were obtained from 250/2424 (10.3%) endourologists polled. Locked deflection was noted by 8/250 (3.2%). The reported literature and MAUDE database identified one case each. Successful removal was noted in four using retrograde manipulation techniques while a percutaneous approach was used in three patients. Open surgery was needed in two cases because of resultant ureteral avulsion, and in one case, an open ureterotomy was needed for ureteroscope extraction. According to our survey, locked deflection was reported to the patient in 4/8 cases, the hospital in 3/8 cases, and the Food and Drug Administration (FDA) 0/8 cases. The two cases reported outside of our survey both notified the FDA. The minority of respondents (2/8), including our group, felt improper surgical technique was responsible for resultant locked deflection. Specifically, removal of a completely deflected ureteroscope through a stenotic infundibulum should be avoided. Rather, in such a situation, the ureteroscope should be straightened under fluoroscopy before being withdrawn.
  
  
  CONCLUSIONS
  Locked deflection of a flexible ureteroscope is rare and underreported. Some cases are attributed to surgical technique, and awareness is crucial for avoidance of this complication.
authors.affiliation: Department of Urology, Thomas Jefferson University , Philadelphia, Pennsylvania.
authors.forename: Scott G
authors.initials: SG
authors.lastname: Hubosky
authors.affiliation: Department of Urology, Thomas Jefferson University , Philadelphia, Pennsylvania.
authors.forename: Amar J
authors.initials: AJ
authors.lastname: Raval
authors.affiliation: Department of Urology, Thomas Jefferson University , Philadelphia, Pennsylvania.
authors.forename: Demetrius H
authors.initials: DH
authors.lastname: Bagley
mesh_terms: D000328:Adult; D004868:Equipment Failure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D014481:United States; D014515:Ureteral Diseases / Q000175:diagnosis*; D020709:Ureteroscopes / Q000592:standards*; D018666:Ureteroscopy / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data