Ge. Kopchok et al., NEW DEVICE FOR VISUAL NEODYMIUM-YAG LASER PROSTATE ABLATION - ACUTE AND CHRONIC CANINE EVALUATION, Lasers in surgery and medicine, 15(3), 1994, pp. 254-262
This canine study (n = 6) evaluated the acute and chronic effects of N
d:YAC; laser prostatectomy using a Prolase II fiber. The Prolase II de
vice consists of a 1,000 mu m quartz fiber which directs a cone of Nd:
YAG; laser energy, at 45 degrees to the aids of the fiber, into the pr
ostatic urethra under direct visual guidance [visual laser ablation of
prostate, (VLAP)]. Under visual guidance and saline irrigation, 60 se
conds of 60 watts of laser power was delivered at 3, 6, 9, and 12 o'cl
ock positions (14,400 J). One canine was instrumented but received no
laser energy (control). One prostate was harvested acutely. The remain
ing four laser-treated dogs were evaluated at 6 to 16 weeks. The histo
pathology of acute laser effects shows areas of necrosis with loss of
glandular structures and stromal edema. Surrounding this area was a zo
ne of degenerative glandular structures extending up to 12.6 mm into t
he prostate. Two of the four dogs developed urinary retention at 6.5 a
nd 9 weeks. On examination, both were found to have fibrotic stricture
s at the distal prostatic urethra with markedly dilated proximal prost
atic urethral lumens (1.98 and 2.8 cm). Two other dogs showed no signs
of urinary retention at sacrifice. Histopathology, both the 6 and 16
week laser-treated animals without urinary retention demonstrated dila
ted prostatic urethras with maximum cross-sectional diameters of 1.52
and 1.50 cm, respectively. However, the 16 week dog demonstrated mild
distal urethral narrowing by urethrogram. The control dog demonstrated
normal histology of the prostate at 16 weeks. This study demonstrates
the safety and initial results of a delivery device for transurethral
laser prostate ablation in a canine model. Further studies are needed
to evaluate the cause of the fibrotic urethral strictures in this mod
el and determine its clinical relevance. (C) 1994 Wiley-Liss, Inc.