Syndactyly (Webbed Toes or Fingers)
What You Need to Know
Syndactyly occurs when toes or fingers don’t separate as they should while a baby forms in the womb. The most common type — simple syndactyly — occurs when skin and soft tissue connect the digits. Treatment for syndactyly includes surgery to separate the webbed toes or fingers. After surgery, a child may need physical and occupational therapy.
What is syndactyly?
Syndactyly (pronounced sin-) is a type of congenital limb difference that is present at birth. At least two toes or fingers (digits) don’t separate as they should while a baby forms in the womb. The digits fuse together, creating a webbed appearance.
Approximately 1 in 2,000 newborns have a form of syndactyly, with webbed toes occurring more often than webbed fingers. For about half of children with syndactyly, webbed digits occur in both feet or both hands (bilateral syndactyly).
Some children with syndactyly also have:
- Rotated or angled fingers
- Unformed nailbeds
How is syndactyly diagnosed?
A prenatal ultrasound sometimes detects syndactyly in unborn babies. More commonly, webbed toes or fingers are noticeable after birth. An X-ray can determine the type and extent of the fusion. A doctor may also order a genetic test (a type of blood test) to check for gene mutations or conditions that cause syndactyly.
Syndactyly Types
Syndactyly typically fuses together the second and third toes or the middle and ring fingers. But it can affect other digits, including the big toe or thumb. The skin between the fused digits may look like webbing.
There are different types of syndactyly. Imaging tests, such as X-rays, can show which type a child has based on how the digits fuse and the extent of their fusion.
Fusion Types
Types of fusion include:
- Simple syndactyly: Skin fuses the digits together. This type is the most common.
- Complex syndactyly: Bones, nerves and blood vessels fuse the digits together.
- Complicated syndactyly: The fused fingers have extra bones, tendons or ligaments.
Extent of Fusion
In addition, the extent of the fusion may be:
- Incomplete (partial): A small section of the digits fuses together.
- Complete: The digits fuse together from the base to the nailbed.
Related Limb Differences
Some children have syndactyly along with one of these congenital limb differences:
- Extra digits (polydactyly)
- Short or undeveloped digits (symbrachydactyly)
What causes syndactyly?
In most cases, syndactyly occurs without a specific cause. Something affects bone or soft tissue formation while a baby develops in the womb. Less commonly, a child inherits a mutated gene from a parent that causes webbed digits.
Boys and white children are more likely to have syndactyly. Children with certain genetic disorders are also more at risk. These conditions include:
- Congenital constriction band syndrome
- Cornelia de Lange syndrome
- Craniofacial abnormalities
- Fetal hydantoin syndrome
- Down syndrome (trisomy 21)
- Poland syndrome
- Smith-Lemli-Optiz syndrome
Syndactyly Treatments
Syndactyly is treatable with surgery, which takes place during early childhood. Children with webbed fingers need surgery to separate fingers, improve hand function and ensure that digits grow as they should.
However, separating the toes can improve how the foot looks. Talk to your doctor about the best treatment for your child.
Syndactyly treatments include:
Syndactyly Surgery
Separating fused bones, nerves and blood vessels (complex syndactyly) is more involved than separating skin (simple syndactyly). Surgery to separate fused digits typically takes place when a child is between 6 months and 2 years old.
A doctor may need to reconstruct or reposition digits, as well as perform a skin graft. This procedure involves taking skin from one part of a child’s body and attaching it to the newly treated area. The grafted skin helps heal the wound.
Depending on the severity of the condition, some children may need staged surgical procedures.
What is the outlook for children with syndactyly?
Children who get surgery for syndactyly often have good function and movement of the treated foot or hand. The digits usually grow as expected. Untreated webbed toes do not typically cause problems. But untreated webbed fingers can negatively affect how well a person can use their fingers and hands throughout their lives.
