Spectrum of anorectal anomalies in pygopagus twins

Abstract

The literature lacks a concise description of the anorectal anomalies encountered in pygopagus twins. This is a retrospective literature review of 34 pygopagus twins highlighting their anorectal malformations. 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. 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.