DYNAMIC URINARY GRACILOPLASTY IN MALE GOATS - A STUDY ON HISTOLOGY AND URETHRAL PRESSURES

The purpose of this study was to investigate the feasibility of dynami c bulbous urinary graciloplasty with respect to graciloplasty histolog y and urethral pressures. Two adult male goats underwent a pulled-thro ugh bulbous urethral graciloplasty with implant of electrodes and a pu lse stimulator. Afterwards, a stimulation protocol was applied to have the fatiguable type II fibers replaced by fatigue-resistant type I fi bers. Urethral pressure profilometry as well as analysis of histology was performed afterwards and compared with preoperative biopsies and p reoperative recorded urethral pressures. Successful conversion from ty pe II into type I muscle fibers was observed; the percentage of type I fibers increased from 29% to 83%. The percentage of connective tissue increased from 8% to 16%. No stricturing of the bulbous urethra was o bserved. The urethral pressures before stimulation increased from a me an of 107 cm H2O without stimulation, to 187 cm H2O with stimulation f or the two goats. After training, the urethral pressure increased from a mean of 85 cm H2O without stimulation, to 118 cm H2O with stimulati on. In male goats, successful dynamic urinary graciloplasty at the bul bous urethra is feasible. The achieved muscle fiber conversion guarant ees fatigue-resistance, necessary for a continuous sphincteric muscle contraction. The maximal urethral pressures, however, are lower than t hose without stimulation. (C) 1997 Wiley-Liss, Inc.