The pathogenesis of genitourinary prolapse and stress incontinence of urine. A histological and histochemical study.

Histological and histochemical analysis of biopsy samples of pubococcygeus muscle obtained from asymptomatic women and from women with stress incontinence of urine, with or without genitourinary prolapse, have been compared. In the asymptomatic women both age and parity appeared to be related to the morphological features of the samples and in particular those obtained from the posterior part of the pubococcygeus. In the symptomatic women there was a significant increase in the number of muscle fibres showing pathological damage which were obtained from the posterior part of the pelvic floor. The range of diameters of both Type I and Type II fibres obtained from this region was significantly different between symptomatic and asymptomatic women. These findings may be attributable to partial denervation of the pelvic floor in patients with urinary stress incontinence with or without genital tract prolapse.