ABSTRACT
Damage to the anal sphincters and the pelvic floor after vaginal deliveries is among the most common causes of surgically treatable incontinence. A generalized weakness of the sphincters and the pelvic floor due to a neurogenic damage is common after an obstetric tear. Anal ultrasonography revealed changes within either or both of the internal and external sphincters in many of these patients with tears, possibly related to the reduced sphincter function. The function of the anal sphincters has recently been evaluated prospectively with physiological techniques and anal ultrasonography. In many patients with incontinence after an obstetric tear the defect in the sphincter muscle can be identified clinically, whereas in others the sphincter defect is first diagnosed with anal ultrasonography. In addition to the mechanical sphincter defect, about 50% of the patients also have a “pudendal neuropathy” with an increased single fiber density and prolongation of the pudendal nerve terminal motor latency.
