InterStim for Fecal Incontinence

InterStim treats fecal incontinence by controlling the nerves that innervate the muscles that control continence.

The two muscles that maintain continence of stool and gas are the internal anal sphincter and the external anal sphincter. Injury to either or both muscles during childbirth can result in fecal incontinence. Direct injury is the result of trauma to the muscles. Indirect injury is the result of trauma to the nerve supply to the muscles.

InterStim affects the sacral nerves. The external anal sphincter is stimulated by the sacral nerves. The internal anal sphincter is inhibited by the sacral nerves. The InterStim battery is an intermittent pulse generator or IPG that stimulates the device’s leads along the sacral nerve. The setting on the IPG is adjusted until continence is achieved by stimulating the external anal sphincter and decreasing the inhibition of the internal anal sphincter.