Pygopagus conjoined twins: A case report and neurosurgical nuances in separation surgery

Background: Conjoined twins are univitelline, monochorionic, and monoamniotic, with imperfect division. The estimated worldwide prevalence is 1.47/100,000 births, with approximately 50% resulting in live births. They are classified according to the most prominent site of fusion. Pygopagus twins are joined at the sacral region and are the third most common variation, representing 6–19% of conjoined twins. Pygopagus twins may have a fused spinal canal and spinal cord, presenting a neurosurgical challenge during separation surgery. Case Description: We report the case of conjoined twins diagnosed prenatally by ultrasound, who, on radiological investigation after birth, were identified as pygopagus twins with fusion of the lumbosacral vertebral canal and a “U”-shaped spinal union. They underwent successful separation surgery using neuromonitoring. Conclusion: Pygopagus twins with a fused spinal canal and spinal cord are a neurosurgical challenge during separation surgery. It is a rare condition; therefore, meticulous planning is essential for a good prognosis.