Effect of naftopidil on urethral obstruction in benign prostatic hyperplasia: assessment by urodynamic studies.

Thirty-two patients with voiding dysfunction attributable to symptomatic benign prostatic hyperplasia were treated with naftopidil, an alpha 1-blocker, at doses of 25-75 mg/day for 4-6 weeks. The efficacy of the drug was assessed from the changes in urinary symptoms and urodynamic data. Total symptom scores were significantly reduced after treatment (P < 0.001). Average flow rate and maximum flow rate were significantly increased (P < 0.001 and P < 0.001, respectively), and residual urine volume, residual urine rate (ratio of residual urine volume/sum of voided volume and residual urine volume), and maximum urethral closure pressure were significantly (P < 0.05, P < 0.01, and P < 0.05, respectively) reduced, and at bladder capacity, the first desire to void was significantly (P < 0.05) increased. The pressure/flow study demonstrated no changes in intravesical pressure at maximum flow, but a significant (P < 0.05) reduction in minimum urethral resistance. A mild side effect (dizziness) was noted in one patient (3.3%), which soon disappeared after the dose was decreased. The efficacy was good or excellent in 21 of 30 patients (70.0%). The drug was evaluated to be promising in the treatment of bladder outlet obstruction due to benign prostatic hyperplasia.

Scintigraphic assessment of lower urinary tract function in children with and without outflow tract obstruction.

Analysis of lower urinary tract function with an extension of standard renography with 123I-hippurate was carried out in 199 children. Maximum bladder capacity, voiding and residual bladder volumes, average and maximum urine flow rates and urine flow patterns were estimated. The index of urine transport (IUT), representing the relationship between urine flow rate and bladder volume, was introduced as a measure of outflow capability. Of 129 children without evidence of outflow obstruction, 90% had a normal urine flow pattern; in 96% the average IUT was 0.8 or higher and in 87% the maximum IUT was 1.2 or higher. A sawtooth-shaped pattern with both normal and abnormal IUT values was observed in 10% of these children. In 63% of the children with outflow tract obstruction there was a low, flat urine flow pattern together with decreased IUT values. A sawtooth-shaped pattern with varying IUT values was observed in 15%, whereas in 20% the urine flow pattern and IUT values were normal. This extension of standard radionuclide renography as a method of screening lower urinary tract function is recommended. It is at least as good as conventional direct urine flow rate recording, it has the advantage of being non-invasive and it is also part of an established urological investigation.

Assessment of urethral resistance at external sphincter zone during voiding by static withdrawal urethrometrogram.

We investigated the intraurethral pressure changes at the external sphincter zone during voiding act and during an attempt to contract the anal sphincter on 26 neurologically intact subjects (normal group) and 12 cases after intrapelvic surgery (6 after amputatio recti and 6 after radical hysterectomy) (disturbed group). During voiding the pressure was decreased in 25 of 26 cases of the normal group, but was increased in 11 of 12 cases of the disturbed group. In contracting the anal sphincter, urethral pressure rose in all cases of both normal and disturbed groups. A significant positive correlation (p less than 0.01) was found in the urethral pressure changes between voiding and during the attempt to contract the anal sphincter in the disturbed group, but not in the normal group. It is supposed that the pressure decreased during voiding is an indication of not only normally functioning external urethral sphincter but also non-underactive detrusor, and that the pressure increase means either underactive detrusor or spastic external urethral sphincter due to detrusor-sphincter dyssynergia. To measure the urethral pressure changes at the external sphincter zone during voiding is thought to be useful for assessment of the urethral resistance at that zone.

The assessment of prostatic obstruction from urodynamic measurements and from residual urine.

One hundred and seventeen males over the age of 55 were investigated for possible prostatic obstruction. About half of the cases in this series could have been objectively classified as unobstructed or obstructed from the maximum flow rate alone. In about two-thirds of the cases obstruction could be satisfactorily assessed from the maximum flow rate together with the detrusor pressure at maximum flow. It was not helpful to combine these 2 measurements into a single urethral resistance factor. In the remaining one-third of the cases, obstruction could be objectively assessed only from a plot of detrusor pressure against flow rate throughout micturition. In many of these cases both the pressure and the flow rate were low and the main peculiarity was that the contractile power of the bladder was weak. Residual urine is a sign of an abnormality of bladder function rather than the direct result of urethral obstruction.