Urodynamic characterization of nonobstructive voiding dysfunction in symptomatic elderly men

Purpose: The pathogenesis of lower urinary tract symptoms in men without bl adder outlet obstruction has not been well characterized. Therefore, we def ined the urodynamic abnormalities associated with symptomatic nonobstructiv e voiding dysfunction, and determined the relationship between age and type of dysfunction. Materials and Methods: Video urodynamic studies of symptomatic men without outlet obstruction were examined. The criterion for a normal bladder outlet -was a pressure gradient across the prostatic urethra, of 5 cm. water or le ss in the absence of distal stricture. A maximum isometric contraction pres sure less than 60 cm. water was regarded. as impaired detrusor contractilit y. Detrusor instability was defined as involuntary detrusor contractions du ring filling or the inability to suppress a detrusor contraction after init iation of flow, Patients were categorized into 4 groups based on the urodyn amic findings. Results: Of 193 men (mean age 69.6 +/- 10.5 years) 40.9% had detrusor insta bility (group 1), 31.1% had impaired contractility (group 2), 10.8% had det rusor instability and impaired contractility (group 3), and 17.1% were urod ynamically normal. (group 4). Average patient age was significantly lower i n group 4 than all other groups. Bladder capacity was lowest in group 1, an d group 3 had the lowest voiding efficiency. Maximum flow rate, bladder com pliance and symptom scores were not different among the 4 groups. The preva lence of detrusor instability with and without impaired contractility incre ased, while the proportion of patients without urodynamic abnormalities dec reased with age. Bladder contractility did not correlate with age. Conclusions: The nonobstructed patient population comprises several groups that are functionally distinct while symptomatically similar. Thus, treatme nt of nonobstructed cases based on symptoms may lead to inappropriate pharm acological therapy and unsuccessful clinical outcomes.