Syndactyly is classified as Type II, failure of differentiation / separation
Syndactyly is the webbing or fusion of two or more digits and is one of the most common congenital deformities of the hand. Surgical release of the digits is the only treatment for syndactyly. Early release can prevent malrotation and angulation that develops as the child grows. Therefore early intervention is important. Releases are recommended to begin between the ages of 6 months to 1 year.
Cause: Syndactyly is a result from failure of the interdigit mesenchymal tissue to undergo apoptosis (programmed cell death) during the 6th through 8th weeks of gestation.
Syndactyly is often an autosomal dominant trait.
5 different presentations of Syndactyly:
- Incomplete: The webbing terminates proximally, does not extend the full length of the digit
- Complete: The webbing extends to the fingertips, the full length of the digit
- Simple: Only soft tissue lies between the syndactylized digits
- Complex: Syndactylized digits have bony or cartilaginous fusions
- Complicated: There may be missing or extra phalanges or musculotendinous or neurovascular abnormalities
* Synonychia – is when two or more fingers share a common nail. This can involve fusion of two or more nails of the fingers or toes.
Time to Play the Brain Game:
Q) What comic actor claims to have webbed toes?
A) Dan Aykroyd
Surgery for Syndactyly:
The surgeon faces challenges for these interdigital separation surgeries because the patient can have nerve and blood vessel anomalies associated with the congenital deformity. Vessels can be entwined or absent. If both sides of a digit are affected, only one side can be separated at a time to avoid vascular insufficiency. Staged surgeries may be necessary. There is a shortage of skin because the separated fingers have a greater surface area than the syndactylized digits, therefore additional skin coverage is almost always needed. There are many types of reconstructive surgical options that include the use of split-skin grafting, full thickness skin grafts, or local skin flaps.
This strawberry shows how the surgical wound will require full coverage with flaps or skin grafting.
There is no gold standard operation for syndactyly releases. However, all methods employ a common set of techniques and guidelines:
- Divide the fingers using triangular / zig zag incisions
- Identify the neurovascular bundle and take great care not to injure
- Harvest the skin graft from a hairless region with the best color match
- Full thickness grafts are preferred over split grafts because full thickness grafts are less likely to contract
- Most common donor site is the inguinal region
- Resurface the surgical wound with flaps or grafts
- Suture flap or graft into place
- Use a meticulous approach for the reconstruction for preservation of the vascular supply
- If more than one digit is syndactylized and staged surgeries are needed, then the surgeon should release a border digit to optimize function of the hand
- When resurfacing the web space it is critical that there is good blood flow to the area
- Web space reconstruction is based on the appearance of the web spaces of the other digits
Magnifying loupes are used by many hand surgeons for better visualization during surgery. With a range of 2.5 to 4 times the magnification the doctor can see intricate details of the work area and perform delicate surgeries on a small scale. This special eyewear is expensive and is customized for each surgeon. The surgeon selects the magnification level needed, style and fit.
Time to Play the Brain Game:
Q) Where is syndactyly most common – between which fingers?
A) 3rd web space or middle and ring fingers.