The dynamic continence challenge – a simple test to predict faecal continence before colostomy closure

Background. A common problem in clinical practice is predicting whether a patient will be continent after treatment of a severe perineal injury. Several tests have been described. Anal manometry is unreliable; continence can be normal with low pressures, and poor with high or normal pressures. Endo-anal ultrasound only illustrates anatomical sphincter integrity. The saline continence test involves the quite unphysiological instilling of saline into the rectum, and assessing seepage. What is needed in the prediction of continence is a normal stool simulator. Method. We propose the use of powdered instant mashed potato reconstituted with water to the consistency of faeces. About 100 - 150 ml is introduced into the rectum using a catheter-tipped syringe. The patient is instructed to walk around for half an hour. On return the underwear is examined for any soiling. If there is no leakage the colostomy may be reversed. Results. Over the past 15 years, 53 patients have undergone this test. In 47 patients there was no leakage, all had their stomas reversed, and none was incontinent during follow-up. Conclusion. The dynamic continence challenge is an accurate physiological test that allows clinicians to simulate the effects of colostomy reversal and assess a patient’s continence before actually proceeding to the reversal.