DETRUSOR CONTRACTILITY AND COMPLIANCE CHARACTERISTICS IN ADULT MALE-PATIENTS WITH OBSTRUCTIVE AND NONOBSTRUCTIVE VOIDING DYSFUNCTION

Purpose: To understand better the contractility and compliance charact eristics of the detrusor in patients with varying degrees of outlet ob struction, we analyzed urodynamic studies in elderly men with obstruct ive and nonobstructive voiding dysfunction. Materials and Methods: All patients were evaluated with video urodynamics, including cystometry, isometric tests, voiding profilometry and post-void residual measurem ent. Bladder compliance, detrusor contractility, detrusor reserve, det rusor instability and the severity of outlet obstruction were determin ed in each patient. Patients were stratified into 4 groups: urodynamic ally normal, detrusor instability, outlet obstruction and outlet obstr uction with detrusor instability. Results: A significant correlation w as found between the maximum isometric contraction pressure and the se verity of obstruction in 168 patients. Maximum isometric contraction p ressure was significantly greater in patients with than without obstru ction, independent of detrusor instability. Although compliance was no t significantly different among the groups, the proportion of patients with poor compliance (less than 30 ml./cm. water) was lowest in the n ormal group. The detrusor reserve was significantly less in patients w ith chronic retention (post-void residual more than 200 mi.) than in t hose with lower post-void residuals. Conclusions: The increase in detr usor contractility with increasing outlet obstruction suggests a compe nsatory response to obstruction. Furthermore, a decrease in bladder co mpliance does not appear to be a consistent finding in patients with o utlet obstruction, although the proportion of patients with poor compl iance is higher in the group with obstruction and/or detrusor instabil ity than in those with normal urodynamic findings. The decrease in det rusor reserve in patients with high post-void residual volumes suggest s that the detrusor reserve reflects the degree of detrusor decompensa tion.