summary Syndactyly is the most common congenital malformation of the limbs and is characterized by abnormal connections of digits of the hand. Diagnosis is made clinically. Treatment is usually digit release performed at ~ 1 year of age. Epidemiology Incidence 1 in 2,000 - 2,500 live births Demographics M > F Caucasians > African Americans Ray involvement 50% long-ring finger 30% ring-small finger 15% index-long finger 5% thumb-index finger Etiology Pathophysiology failure of apoptosis to separate digits Genetics autosomal dominant in cases of pure syndactyly reduced penetrance and variable expression positive family history in 10-40% of cases Associated conditions acrosyndactyly digits fuse distally and proximal digit has fenestrations (e.g., constriction ring syndrome) Poland Syndrome Apert Syndrome Carpenter syndrome acrocephalopolysyndactyly Classification Syndactyly Classification Simple Only soft tissue involvement, no bony connections Complex Side to side fusion of adjacent phalanges Complicated Accessory phalanges or abnormal bones involved in fusion Complete vs. Incomplete Complete syndactyly the skin extends to finger tips; with incomplete, skin does not extend to fingertips Treatment Operative digit release indications syndactyly perform at ~ 1 year of age acrosyndactyly perform in neonatal period Technique Digit Release if multiple digits are involved perform procedure in two stages (do 1 side of a finger at a time) to avoid compromising vasculature release digits with significant length differences first to avoid growth disturbances release border digits first (ring-little, and thumb-index) at <6mths because of differential growth rates between ring-little and between thumb-index digits middle-ring syndactyly can be released later (2yr old) as because middle and ring digits have similar growth rates thus if syndactyly involving index-middle and ring-small digits, release index-middle and ring-small first, and leave the central syndactyly (middle-ring) for 6 months later do all releases before school age bilateral hand releases perform simultaneously if child is <18mths (less active) perform staged if child is >18mths (more active, hard to immobilize bilateral limbs simultaneously) interdigitating zigzag flaps are created during release to avoid longitudinal scarring dorsal fasciocutaneous flaps to reconstruct the web use only absorbable sutures (5-0 chromic catgut) which have less inflammation Complications Web creep most common complication of surgical treatment (8-60%) causes early creep is most commonly caused by necrosis of the tip of the dorsal quadrilateral flap and loss of full-thickness skin graft placed in the web late creep (adolescence) is caused by discrepant growth between scar/skin graft and surrounding tissue during the growth spurt treatment reconstruct web space with local skin flaps Nail deformities