title: Photoselective vaporization prostatectomy: experience with a novel 180 W 532 nm lithium triborate laser and fiber delivery system in living dogs.
abstract: OBJECTIVE
  We studied vaporization parameters, and anatomical and histopathological outcomes of photoselective vaporization of the prostate with the novel GreenLight™ XPS™ 180 W, 532 nm lithium triborate laser and MoXy™ fiber in a survival model of living dogs. We compared these findings with those of the existing GreenLight HPS™ 120 W 532 nm lithium triborate laser photoselective vaporization of the prostate in living dogs.
  
  
  METHODS
  Eight dogs underwent antegrade photoselective vaporization of the prostate with the 180 W laser delivered through a new 750 μm (vs the existing 600 μm core diameter), 50% larger, spot sized, side firing fiber. Four dogs were sacrificed 3 hours and 8 weeks postoperatively, respectively. We recorded laser energy and time. Prostates were sectioned, measured and histologically analyzed after hematoxylin and eosin, triphenyltetrazolium chloride or Gomori trichrome staining and compared with a normal control.
  
  
  RESULTS
  Photoselective vaporization of the prostate with the 180 W laser bloodlessly created a 76% larger cavity (mean 11.8 vs 6.7 cm(3), p = 0.014), vaporized tissue at a 77% higher rate (mean 2.3 vs 1.3 cm(3) per minute, p = 0.03) and did so in 37% less time per volume vaporized (0.5 vs 0.8 minutes per cm(3), p = 0.003). Hematoxylin and eosin, and triphenyltetrazolium chloride staining histologically revealed a 33% thicker mean coagulation zone vs that of 120 W laser photoselective vaporization of the prostate (2.0 ± 0.4 vs 1.5 ± 0.3 mm, p <0.005). In prostates healed for 8 weeks postoperatively hematoxylin and eosin, and Gomori trichrome staining showed re-epithelialized cavities with negligible submucosal fibrosis compared with a normal prostate.
  
  
  CONCLUSIONS
  GreenLight XPS 180 W 532 nm lithium triborate laser photoselective vaporization of the prostate with the MoXy fiber has a significantly higher vaporization rate and speed with a deeper hemostatic coagulation zone but favorable tissue interaction and healing equal to those of HPS 120 W laser photoselective vaporization of the prostate in dogs.
authors.affiliation: Department of Urology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Reza S
authors.initials: RS
authors.lastname: Malek
authors.forename: Hyun Wook
authors.initials: HW
authors.lastname: Kang
authors.forename: Yihlih Steven
authors.initials: YS
authors.lastname: Peng
authors.forename: Douglas
authors.initials: D
authors.lastname: Stinson
authors.forename: Michael T
authors.initials: MT
authors.lastname: Beck
authors.forename: Ed
authors.initials: E
authors.lastname: Koullick
mesh_terms: D000818:Animals; D004285:Dogs; D007150:Immunohistochemistry; D017075:Laser Coagulation / Q000295:instrumentation / Q000379:methods; D053685:Laser Therapy / Q000295:instrumentation / Q000379:methods* / Q000401:mortality; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008297:Male; D023421:Models, Animal; D009929:Organ Size; D011183:Postoperative Complications / Q000473:pathology / Q000503:physiopathology; D011467:Prostate / Q000473:pathology* / Q000601:surgery*; D011468:Prostatectomy / Q000295:instrumentation* / Q000379:methods / Q000401:mortality; D011897:Random Allocation; D015996:Survival Rate; D014835:Volatilization