Brief communication (Original). Anorectal physiology evaluation after male-to-female sex reassignment surgery

Background: Male-to-female sex reassignment surgery (MTF-SRS) is a treatment for gender identity disorders (GID) wherein the penis is removed and an epithelialized neovagina is created in the retroprostatic or rectovesical space. This is a space between the double layers of Denonvilliers’ fascia that contains motor, sensory, and autonomic nerves to the pelvic organs. Injury to these nerves may lead to anorectal dysfunction. However, there has been no objective study of anorectal physiologic changes after SRS.Objectives: To compare anorectal physiological parameters, before and after, male-to-female sex reassignment surgery (SRS) and to evaluate the effects of SRS on anorectal physiology.Methods: In 10 patients with MTF GID who underwent SRS at King Chulalongkorn Memorial Hospital, anorectal manometry was performed using a water perfused catheter (Mui Scientific, Ontario, Canada) and a state-of-the-art anorectal manometry system (Medtronic, Minneapolis, MN, USA) at the Gastrointestinal Motility Research Unit at 2 weeks before and 3 months after the SRS. Data were analyzed using PolygramNet software. Anal sphincter pressures (mmHg) with volume used to elicit rectal sensation (mL).Results: There was no significant change in the resting anal sphincter pressure, anal sphincter squeezing pressure, sustained squeezing pressure, and duration of squeeze, rectal sensation, and threshold of the desire to defecate affected by SRS. Cough reflex and rectoanal inhibitory reflex were normal both before and after SRS in all patient participants.Conclusions: Sex reassignment surgery seems to produce no effect on clinical anorectal functions. This was proven by absence of clinically significant changes in anorectal manometry.