Syndactyly - Hand - Orthobullets

Introduction

Most common congenital malformation of the limbs
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
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

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-ring-small digits, releae index-middle and ring-small first, and leave the central syndactyly (middle-ring) for 6months 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