The relationship of detrusor instability and symptoms with objective parameters used for diagnosing bladder outlet obstruction: a prospective study.

Purpose: Detrusor instability is a common urodynamic finding in patients with prostatic obstruction. In prospective fashion we evaluated detrusor instability in patients with lower urinary tract symptoms attributable to benign prostatic hyperplasia and determined its possible association with the degree of obstruction.

Materials And Methods: A total of 459 men with a mean age plus or minus standard deviation of 60.4 +/- 9.4 years who were investigated for lower urinary tract symptoms at our facility answered an Arabic standardized version of International Prostate Symptom Score and underwent simple uroflowmetry, outpatient cystoscopy and transrectal ultrasound. Invasive urodynamics, including filling and voiding cystometry, was done with pressure flow analysis according to the Schäfer nomogram. Statistical significance was tested by the Mann-Whitney U and Wilcoxon rank sum tests.

Results: Of the 459 patients 108 (23.5%) had detrusor instability. Instability significantly affected patient symptom score and conception of quality of life. Moreover, instability significantly affected the degree of obstruction, as measured by the maximum flow rate, post-void residual urine, prostate volume and Schäfer grade of obstruction.

Conclusions: Detrusor instability affects patient symptoms and quality of life. It also signifies a more severe degree of obstruction in male patients with lower urinary tract symptoms and bladder outlet obstruction due to benign prostatic hyperplasia.