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MIYAGAWA, I. Urethral Pressure Changes during Voiding. Tohoku J. exp. Med., 1984, 142 (4), 467-468 - Intraurethral pressure changes in the external sphincter zone during voiding were recorded using a specially constructed double lumen urethral catheter in 3 normal subjects. It was noted in all the 3 subjects that the urethral pressure in this zone dropped simultaneously with decrease of electromyographic activities of the external urethral sphincter when the subjects strained to void. It was ascertained for the catheter position to remain unchanged irrespective of voiding action during urethrometrography. -urethral pressure change; voiding

Between 1975 and 1984 we performed 17 bladder neck reconstructions with bladder neck suspension using intraoperative urethral pressure profilometry. Studies were done intraoperatively after bladder neck reconstruction and then they were repeated after bladder neck suspension. A continence length of 25 to 35 mm. and a urethral closure pressure of greater than 60 cm. water were obtained in all patients. Bladder neck suspension was noted to increase the continence length in all patients and allowed for at least a 2-fold increase in the closure pressures that were obtained. Urinary continence was assessed postoperatively from parental interviews. It seems important to achieve an initial closure pressure of at least 60 cm. water, while at the same time attempting to ensure anterior fixation. Intraoperative urethral pressure profilometry can serve as a valuable adjunct to bladder neck reconstruction by confirming the adequacy of bladder neck resistance after bladder neck reconstruction and again after bladder neck suspension.

Pressure changes in the urinary bladder due to respiration were measured in 75 bitches. The changes fell within a narrow range (0·5 to 2·5 cm water) and were unaffected by size or whether the bitches were entire or spayed. Significant differences were found, however, between continent (mean ± sd , 1·1 ± 0·4 cm water) and incontinent (mean ± sd , 1·4 ± 0·5 cm water) animals (P

Combined electromyographic and gas urethral pressure profilometry provide for rapid assessment of urethral function in neurological dysfunction of the detrusor muscle and urethra.

NISHIZAWA, O., MORIYA, I., SATOH, S., HARADA, T. and TSUCHIDA, S. Effect of Verapamil on the Lower Urinary Tract. Tohoku J. exp. Med. 1983, 140 (2), 223-224 - The effect of verapamil on the in-vivo bladder and urethra was investigated in female dogs. The bladder and urethral pressure responses to electrical stimulation of the pelvic and hypogastric nerves were decreased by verapamil.

It has been postulated that one factor involved in the pathophysiology of stress urinary incontinence is the sustained decrease in urethral closure pressure in response to a sudden increase in intra-abdominal pressure. Twenty-one patients with stress-related pressure decrease (group 1) and seven patients with stable pressures (group 2) were studied. Although closure pressure in group 1 decreased approximately 27% in response to a single cough in a static setting, when studied dynamically with pressure profiles before and after coughing, there was no pressure decrease seen. The evidence presented suggests that the phenomenon of pressure decrease is in actuality an artifact of measurement and not a true physiologic event. The degree of urethral mobility is related to the perceived pressure decrease.

A Lyodura sling operation for urinary stress incontinence was performed on 36 patients. The success rate was 89%, when success was defined as absence of objective urine loss at coughing or straining, with full bladder in the upright position and during a Urilos test, at least 6 months after surgery. Full urodynamic assessment, including urethral rest and stress profiles, were performed before, and 6 months after, surgery. Success of the operation depended mainly on enhancement of urethral pressure transmission. Functional length of the urethra and maximal urethral pressure did not influence the success rate. The procedure is especially suitable in patients with some degree of uterine or vaginal prolapse.