Anal sphincter function after total mesorectal excision is comparable to that of healthy subjects: results of a matched pair analysis.

Aim: The aim of this paper was to compare healthy subjects and patients after total mesorectal excision concerning anal resting/squeeze pressure and surface-electromyography of the sphincter.

Methods: Forty patients (9 female/31 male) after total mesorectal excision due to low or middle rectal cancer were compared to a sex-, age- and BMI-matched group of healthy volunteers by means of anorectal pull-through manometry using a microtip-transducer system and by means of endoanal surface electromyography using a bipolar plug electrode.

Results: Resting pressure (59.2 ± 3.1 mmHg vs. 68.3 ± 4.3 mmHg; P=0.056) and squeeze pressure (127.3 ± 3.2 mmHg vs. 128.9 ± 4.6 mmHg; P=0.78) were comparable between patients after total mesorectal excision and healthy volunteers whereas surface electromyography amplitude (9.5 ± 0.4 µV vs. 13.9 ± 0.6 µV; P=0.01) was significant lower in patients after total mesorectal excision compared to healthy subjects. Correlation between squeeze and resting pressure as well as between squeeze pressure and surface electromyography were weaker in patients after total mesorectal excision compared to healthy controls.

Conclusion: Objective measurable sphincter pressure after total mesorectal excision seems to be comparable to that of healthy subjects whereas surface-electromyography is significant higher in healthy subjects.