title: Endoscopic assessment and prediction of prostate urethral disintegration after histotripsy treatment in a canine model.
abstract: OBJECTIVE
  Histotripsy is a nonthermal focused ultrasound technology that uses acoustic cavitation to homogenize tissue. Previous research has demonstrated that the prostatic urethra is more resistant to histotripsy effects than prostate parenchyma, a finding that may complicate the creation of transurethral resection of the prostate-like treatment cavities. The purpose of this study was to characterize the endoscopic appearance of the prostatic urethra during and after histotripsy treatment and to identify features that are predictive of urethral disintegration.
  
  
  METHODS
  Thirty-five histotripsy treatments were delivered in a transverse plane traversing the prostatic urethra in 17 canine subjects (1-3/prostate ≥1 cm apart). Real-time endoscopy was performed in the first four subjects to characterize development of acute urethral treatment effect (UTE). Serial postprocedure endoscopy was performed in all subjects to assess subsequent evolution of UTE.
  
  
  RESULTS
  Endoscopy during histotripsy was feasible with observation of intraurethral cavitation, allowing characterization of the real-time progression of UTE from normal to frank urethral disintegration. While acute urethral fragmentation occurred in 3/35 (8.6%) treatments, frank urethral disintegration developed in 24/35 (68.5%) within 14 days of treatment. Treating until the appearance of hemostatic pale gray shaggy urothelium was the best predictor of achieving urethral fragmentation within 14 days of treatment with positive and negative predictive values of 0.91 and 0.89, respectively.
  
  
  CONCLUSIONS
  Endoscopic assessment of the urethra may be a useful adjunct to prostatic histotripsy to help guide therapy to ensure urethral disintegration, allowing drainage of the homogenized adenoma and effective tissue debulking.
authors: Department of Urology, University of Michigan, Ann Arbor, MI 48109, USA.
authors: George R
authors: GR
authors: Schade
authors: Nicholas R
authors: NR
authors: Styn
authors: Timothy L
authors: TL
authors: Hall
authors: William W
authors: WW
authors: Roberts
mesh_terms: D000818:Animals; D004285:Dogs; D004724:Endoscopy / Q000379:methods*; D008297:Male; D023421:Models, Animal; D011184:Postoperative Period; D011467:Prostate / Q000473:pathology* / Q000601:surgery*; D014464:Ultrasonic Therapy / Q000379:methods*; D014521:Urethra / Q000473:pathology* / Q000601:surgery*