Introduction Third and fourth degree perineal tears will occur in a small proportion of vaginal deliveries. When found at the time of delivery, they are typically repaired primarily. Patients may subsequently suffer from faecal incontinence.

Method All patients with a third and fourth degree tear were referred for assessment. This included endoanal ultrasonography and estimation of incontinence with the Cleveland Clinic faecal incontinence score. Data from 2001 to 2013 were analysed.

Results 888 patients were included. Of these, 551 (62%) were found to have a sphincter defect. 333 (38%) had intact sphincters. The majority of these had normal looking sphincters on ultrasonography. The mean (SD) incontinence score for those with a defect was 4.3 (5.5). The mean incontinence score for those with no defect was 4.2 (5.8).

Conclusion The majority of patients had a sphincter defect. This suggests that there is a high failure rate from the primary repair. The high proportion of normal looking sphincters suggests that third and fourth degree tears may be over diagnosed. Despite the ultrasound findings, the incontinence scores for both groups were comparable.

Disclosure of interest None Declared.