Congenital syndactyly: a reappraisal.

Digital syndactyly is a common congenital anomaly and is associated with other anomalies affecting the digits, the hand, the arm or even the entire body. In the past it has been considered a single entity. However, recent information provided by experimental embryology, studies of morphogenesis and other sources, suggests that there are at least two distinct entities: primary syndactyly due to interference with the sequence of events that normally culminate in the division of digits into discrete parts and secondary syndactyly due to readhesion of adjacent digits as a result of close contact between raw surfaces. Primary syndactylyl may arise de novo, or it may occur as a manifestation of a mutation phenomenon or as a genetically controlled syndrome. Secondary syndactyly is the result of mechanical adhesion of adjacent parts involved in a general reparative or healing process. The initial insult leading to amputation of a portion of the digits may or may not be genetically controlled; adhesion is fortuitous. Management of syndactyly is determined by the complexity of the malformation. For simple cutaneous syndactyly the surgeon should make a zigzag incision and provide a rectangular, proximally based flap for the floor of the web, usually before the child is 2 years of age. A full- or split-thickness skin graft should be applied to the defects. For complex deformities involving several digits and associated with postural or osseous malformation, several operative procedures may be required. The surgeon must be vigilant to note and correct the sequelae resulting from recurrent contractures and imbalances associated with growth.