Ultrastructure of detrusor and urethral smooth muscle in women with urinary incontinence.

Abstract

We performed a quantitative study to determine whether mixed urinary incontinence was associated with any ultrastructural changes in detrusor and urethral smooth muscle. Detrusor and urethral smooth muscle biopsy specimens were obtained at the time of laparotomy from 5 women aged 35 to 65 years with mixed urinary incontinence and from a control group of 5 continent women. Smooth muscle morphologic characteristics were assessed from a systematic random sample of electron micrographs. A further 16 urethral biopsy specimens were similarly analyzed to confirm the findings of the initial study. The electron-dense portion of the sarcolemma was smaller in urethral biopsy specimens taken from patients with intrinsic sphincter deficiency than in those from control subjects (chi(2)((1)) = 4.9; P =.027). No other morphologic characteristics were unique to patients with incontinence. Our study suggests that focal adhesion architecture is decreased in urethral smooth muscle of patients with intrinsic sphincter deficiency.