Physiological and functional evaluation of the transposed human pylorus as a distal sphincter.

BACKGROUND/AIMS: Studies evaluating the human pylorus as a sphincter are scanty and contradictory. Recently, we have shown technical feasibility of transposing the human pylorus for end-stage fecal incontinence. This unique cohort of patients provided us an opportunity to study the sphincter properties of the pylorus in its ectopic position.

METHODS

Antro-pylorus transposition on end sigmoid colostomies (n = 3) and in the perineum (n = 15) was performed for various indications. Antro-pylorus was assessed functionally (digital examination, high resolution spatiotemporal manometry, barium retention studies and colonoscopy) and by imaging (doppler ultrasound, MRI and CT angiography) in its ectopic position.

RESULTS

The median resting pressure of pylorus on colostomy was 30 mmHg (range 28-38). In benign group, median resting pressure in perineum was 12.5 mmHg (range 6-44) that increased to 21.5 mmHg (range 12-29) (P = 0.481) and 31 mmHg (range 16-77) (P = 0.034) on first and second follow-up, respectively. In malignant group, median post-operative pressures were 20 mmHg (range 14-36) and 21 mmHg (range 18-44) on first and second follow-up, respectively. A definite tone and gripping sensation were felt in all the patients on digital examination. On distal loopogram, performed through the diverting colostomies, barium was retained proximal to the neo-pyloric valve. Both perineal ultrasound and MRI showed viable transposed graft. CT angiography and color doppler studies confirmed vascular flow in the transposed position.

CONCLUSIONS

The human pyloric valve can function as a tonic sphincter when removed from the gastroduodenal continuity.