BACKGROUND: Neurosurgeons are familiar with the challenges presented by 
craniopagus twins, but other types of conjoined twins may also have 
neurosurgical implications. We report our experience in the management of 
ischiopagus and pygopagus conjoined twins.
METHODS: This is a retrospective review of the management of conjoined twins at 
Red Cross Children's Hospital in Cape Town, South Africa.
RESULTS: Twenty-three pairs of symmetrical conjoined twins were managed over a 
40-year period (1964-2003), of which 16 (70%) were separated. Of these cases, 6 
are the focus of this study, namely 4 pairs of ischiopagus twins and 2 pairs of 
pygopagus twins seen between 1993 and 2003. In 2 cases, there was direct 
involvement of the nervous system at the site of union, with 1 pair of 
ischiopagi manifesting end-to-end union of their spinal cords, while a pair of 
pygopagi had back-to-back fusion of the conus. Another pair of ischiopagi had a 
fused dural sac without joined neural elements, but one of these children 
developed syringomyelia 2 years after separation. Neuroimaging was invaluable in 
detecting these abnormalities. The one pair of ischiopagi who died before 
separation were HIV positive and had severe brain atrophy and cystic 
encephalmalacia at autopsy. Nine of the 12 children (75%) had bony abnormalities 
of the spine remote from the area of conjunction. The most common finding was 
the presence of hemivertebrae, usually in the thoracic spine. Six children 
manifested scoliosis, which has already progressed in the oldest two. Technical 
aspects such as timing and sequence of separation, the division of neural 
tissues and reconstruction are discussed, as are the long-term complications of 
their spinal abnormalities.
CONCLUSIONS: Ischiopagus and pygopagus conjoined twins manifest an interesting 
array of spinal abnormalities, which present challenges, not only at the time of 
separation, but also in their long-term management.