Complex syndactyly is generally defined as abnormal digital interconnection by bone, but sometimes simple syndactyly with complicated cutaneous, musculotendinous or neurovascular interconnections should be considered complex as well. Additionally, complex syndactyly involving anomalous bones (delta phalanx, brachiphalangism...) falls in different category called "complicated". 35 patients with complex or complicated congenital syndactyly are studied and 58 children with cutaneous syndactyly due to burns and epidermolysis bullosa are analyzed as well.