Every time Indian-born paediatric Surgeon Askar Kukkaddy meets the three-year-old twins Abbey and Sarah, a sense of pride like adrenaline rushes through him. Naturally so as Askar had performed a marathon 22-hour surgery for separating the pygopagus twins, when the twins were just five months old at Waikato Hospital, Auckland, New Zealand.  Interestingly, at the time of the surgery in 2004, there were less than 30 reported cases. 
Pygopagus (meaning joined at the lower back, spine and pelvis) is one of the rarest forms of conjoined twins.  Comments Askar, "If you consider that conjoined twins are born at the rate of 1 in 2,00,000 live births there would be twins born with pygopagus about 1 in over 3 million live births!" The fact that these two girls were conjoined twins was revealed only recently. Askar points out that the term Siamese twins should never be used while describing conjoined twins.