Syndactyly
Overview
Syndactyly is the most common congenital malformation of the limbs, with an incidence of 1 in 2000-3000 live births. Syndactyly can be classified as simple when it involves soft tissues only and classified as complex when it involves the bone or nail of adjacent fingers. It is a shared feature of more than 28 syndromes, including Poland, Apert, and Holt-Oram syndromes. Syndactyly is a failure of differentiation in which the fingers fail to separate into individual appendages. This separation usually occurs during the sixth and eighth weeks of embryologic development. The root words of the term syndactyly are derived from the Greek words syn, meaning together, and dactyly, meaning fingers or digits.
Causes
Syndactyly occurs in the womb as a detour on the road to developing one thumb and four separate fingers on the hand. In the womb, the new hand starts out in the shape of a paddle, then splits into separate fingers. Sometimes the fingers don't split apart enough, and webbed fingers result: syndactyly. Sometimes a extra split forms and extra fingers result: polydactyly. Syndactyly and polydactyly are about equally common disorders. Combinations of both can occur as well - webbed extra fingers. Why does a child have this? It is not due to anything the mother did during pregnancy - it just happens. Sometimes these problems are in the genes and can be passed down generation to generation, but many times there is simply no known explanation.
Treatment
Medical Therapy Syndactyly requires surgical intervention. Full-term infants can be scheduled for elective surgical procedures as early as 5 or 6 months of age. Surgery before this age can increase anesthetic risks. Prior to that time, there is generally no intervention necessary if there are no problems. If there is an associated paronychia (see Image 26), which can occur with complex syndactyly, the parents are given instructions to wash the child's hands thoroughly with soap and water and to apply a topical antibacterial solution or ointment. Oral antibiotics are given when indicated. Surgical Therapy The timing of surgery is variable. However, if more fingers are involved and the syndactyly is more complex, release should be performed earlier. Early release can prevent the malrotation and angulation that develops from differential growth rates of the involved fingers.