Separation of pygopagus, omphalopagus, and ischiopagus with the aid of three-dimensional models.

BACKGROUND: The three-dimensional (3D) technique provides with accurate anatomical information. We present the separation surgeries for three different kinds of conjoined twins with the aid of three-dimensional techniques.

METHOD: For the pygopagus twins, a pelvic and lower vertebral model was made. For the omphalopagus and ischiopagus, their enhanced computed tomography (CT) scan images were transferred to the Computer-Assisted Surgery Planning System (CASP) (Hisense, Qingdao, China) to generate the 3D models.

RESULT: In the case of the pygopagus twins, the 3D model clearly showed that their coccyges were joined at a 120°angle from each other horizontally which suggested that the blind-end orifice on their back was a pilonidal sinus, which separated the normal sphincter into two halves. In the omphalopagus, the 3D model revealed one of the branches of each twin's hepatic vein was connected with the other's. The 3D model of the ischiopagus twins revealed that both of the twins had duplicated bladders and each baby's duplicated bladders united with one of the bladders of the other baby and a single rectum passing through the middle of the four bladders.

CONCLUSION: 3D techniques could provide more detailed anatomical information, which is helpful in planning procedures for such complicated separation surgery.

LEVELS OF EVIDENCE: Level IV.