Urodynamic evaluation of lower urinary tract function in cats after perineal urethrostomy with minimal and extensive dissection.

Perineal urethrostomy was performed in five male cats with minimal, sharp intrapelvic transection of the ischiocavernous and ischiourethralis muscles and ventral penile ligaments, and in five male cats with extensive blunt intrapelvic dissection and sharp muscle transection. Urethral pressure profiles and cystometrograms with simultaneous fine wire electrode sphincter electromyography were performed in sedated cats before surgery and on days 14 and 28. Premicturition pressure, urethral opening pressure, maximum detrusor pressure, total volume infused, and residual volume were measured during cystometry, and maximal urethral closure pressure was measured during profilometry. A grading of (+), (++), or ( ) was used to represent the intensity of electromyographic activity. There was no difference between minimal and extensive dissection for any cystometrogram or profile variable at days 14 or 28. Urethral opening pressure and maximal detrusor pressure during cystometrography were higher in preoperative studies than after minimal or extensive dissection. Sphincter electromyography after surgery was not significantly different from preoperative results in either surgical group. The results of this study indicate that neither sharp nor blunt intrapelvic dissection significantly alters the postoperative urodynamic status in male cats.