Spectrum of anorectal anomalies in pygopagus twins

Abstract

Background/purpose: The literature lacks a concise description of the anorectal anomalies encountered in pygopagus twins.

Methods: This is a retrospective literature review of 34 pygopagus twins highlighting their anorectal malformations.

Results: Overall pygopagus twins represent 17% of all conjoined twins. Live-birth pygopagus twins are more commonly female (86%), whereas stillborns are commonly male (80%). Half of the twins had nonfused rectums, and half had fused rectums. The nonfused had 2 rectums (80%) or one rectum and one rectovaginal fistula (20%). The fused had high (46%) or low (54%) rectal junctions. All reported living male pygopagus twins have had nonfused rectums. All can be managed applying the principles of posterior sagittal anorectoplasty.

Conclusions: In general, live-born male pygopagus twins are likely to survive with a nonfused rectum and good bowel function, whereas live-born female pygopagus twins have a good chance of surviving with a fused rectum (high or low), which requires appropriate operative reconstruction.