ABNORMAL INTERNAL ANAL-SPHINCTER FIBROSIS AND ELASTICITY IN FECAL INCONTINENCE

PURPOSE: We aimed to investigate the changes in the proportion of coll agen and in the elasticity of the internal anal sphincter in patients with neurogenic fetal incontinence. METHODS: Collagen content was stud ied in ten patients with neurogenic fecal incontinence (mean age, 51.5 years) and ten controls (age, 58.6 years) using histologic techniques to determine differences between incontinence and health and to deter mine the effect of aging. Changes in elasticity were also measured in 8 controls (mean age, 63 years) and 13 patients with neurogenic incont inence (mean age, 60 years) by recording the in vitro length-tension r elationship of the freshly excised internal anal sphincter. RESULTS: I ncontinent patients had a significantly higher collagen content than c ontrols (55 percent vs. 33 percent; P = 0.013). In incontinent patient s the amount of collagen and the patients' ages correlated significant ly (P = 0.001). There was a greater increase in stable tension per inc rease in muscle length in the strips from incontinent patients compare d with controls. CONCLUSIONS: Changes in fibrous tissue content are li kely to influence muscle tone and responsiveness of the sphincter in f ecal incontinence.