Faecal incontinence: manometric and radiological changes following postanal repair

Ten patients with idiopathic faecal incontinence underwent postanal repair based on clinical assessment of their symptoms. Their manometric and radiological values before surgery were compared with values from 10 normal volunteers and then the changes following surgery were examined and correlated with the clinical results. Anal manometry was performed using a multilumen, low compliance, perfused catheter system. Anorectal angles and perineal descent were established radiologically. Pre-operative manometry demonstrated significant reduction in maximum and squeeze pressure (median 77 mmHg versus 200 mmHg), the volume required to inhibit the rectoanal reflex (median 40 mL versus 70 mL), and the volume retained in the saline continence test (median 400 mL versus 1500 mL). The majority of patients had obtuse anorectal angles (six of 10 at rest), and abnormal perineal descent (eight of 10 on straining). Nine patients have been improved clinically following surgery. Postoperative manometry and radiology have been performed in seven patients and have shown no significant changes. Anal manometry and radiology are objective means of documenting faecal incontinence although their role in selecting patients for surgery is not yet determined. Postanal repair is effective in restoring continence, although the parameters measured have not explained the mechanism of this effect.