Separation of pyopagus conjoined twins: a New Zealand neurosurgical experience.

Conjoined twins represent a rare form of incomplete embryonic separation. They are classified into eight different subtypes, with 18% representing pyopagus conjoints. History is scattered with accounts of the various types of conjoints and it is only recently that strategies have been devised to enable surgical separation of such twins. It is estimated that approximately 20 cases of separation of pyopagus twins have been performed. We provide a historical look at pyopagus conjoint twins and report our neurosurgical experience of Australasia's first separation of pyopagus twin girls.