Primary and Secondary Anal Sphincter Repair

Abstract

Anal sphincter disruption during vaginal delivery remains the commonest reason for performing an anal sphincter repair in women. There is now considerable evidence to suggest that occult mechanical trauma to the anal sphincter sustained during childbirth1–3 is a major etiological factor in the development of fecal incontinence.4 Unfortunately, it has not been established whether these injuries are genuinely occult or possibly undiagnosed and therefore missed at delivery. Taken literally, the terms “primary” and “secondary” anal sphincter repair can be somewhat confusing as they may not always refer to a first and second attempt at sphincter repair; a primary repair is usually performed in the immediate postpartum period following a recognized obstetric anal sphincter rupture. When an anterior repair of the anal sphincter is performed to treat fecal incontinence (usually months or years later), it is regarded as a secondary sphincter repair even though a direct primary repair may or may not have been attempted in the postpartum period. As fecal incontinence may only manifest for the first time many years after the initial obstetric injury, it is not always possible to establish whether a primary repair was performed or if the injury was occult or indeed, just missed. Therefore, in this context, a secondary repair refers to a repair performed secondary to the development of symptoms of fecal incontinence. In the UK, primary repair of a fresh tear is conducted by obstetricians whereas secondary repairs are predominantly performed by colorectal surgeons.