What causes webbed toes in humans?
Usually, surgeons will correct webbed digits when children are quite young to prevent complications.
Most corrective surgeries are successful and give the child full function of their digits on a hand or foot that appears normal.
What are the causes?
Syndactyly refers to toes or fingers not separating during fetal development.
Image credit: pschemp, (2006, July 22).
Syndactyly is one of the most common birth abnormalities, affecting an estimated 1 in every 2,000–3,000 children born each year.
It occurs when the toes or fingers do not separate correctly during fetal development.
Syndactyly can also occur when the skin or another body structure does not heal properly after a significant injury, such as a burn.
Syndactyly often presents as webbing, so people often refer to the condition as webbed toes or fingers.
The majority of cases of webbed toes occur when the skin fails to separate during fetal development.
However, more severe cases of syndactyly may also involve other parts of the body, including:
- blood vessels
Syndactyly may appear as a symptom of another syndrome or medical condition, but most cases are non-syndromic, meaning that they have no apparent cause.
Currently, there are 300 different syndromes linked to syndactyly, most of which are genetic conditions. The most common ones include:
- Down syndrome
- Apert syndrome
- Crouzon syndrome
There is a well-established genetic basis for some types of syndactyly, and most people would consider webbed toes to be an inherited condition. However, researchers still do not understand the full range of factors that cause the condition to develop because each case is different.
According to the available research, boys are more likely to develop syndactyly than girls. And Caucasian children seem to be more likely to develop webbed digits than children from other ethnic backgrounds.
Although it can affect any of the toes or the spaces between them, syndactyly most frequently develops between the second and third toes.
What are the main symptoms?
Each person with syndactyly tends to experience different symptoms, as webbed toes may be:
- Unilateral or bilateral: Impacting only one side of the body or both.
- Severe, moderate, or mild: With digits almost entirely fused, with digits partially fused, or with only minor webbing between digits.
- Symmetric or asymmetric: Appearing alike and in the same region on both sides of the body, or appearing dissimilar or in different places on each side of the body.
- Simple or complex: Involving only two digits or a few bones, or including multiple digits or bones.
- Painful or asymptomatic.
Minor cases may not interfere much with toe or foot movement and function. However, if the toes are severely webbed or fused, the condition can be disabling.
What are the treatment options?
Surgery during infancy is a common treatment for webbed toes.
In most cases, it is possible to correct webbed toes surgically, and this usually occurs between the ages of 12 and 18 months before full development has happened.
It is best to fix webbed toes before they can cause any joint malformation.
A doctor will usually order an X-ray or ultrasound of the webbed area to determine exactly which structures it involves and the best surgical approach.
They may also order blood tests and chromosomal tests to check whether the webbing relates to another condition, or is syndromic, particularly if a child has other physical signs of a genetic syndrome.
The exact surgical procedure to correct webbed toes depends on the severity of the webbing and the structures it involves.
Typical surgical procedure
In most cases, once the child is unconscious, the surgeon will cut through the webbing in a zigzag manner along the midline point.
Cutting the webbing in this way will help to prevent the scarring from interfering with healthy growth and development. If any structures other than the skin are fused, the surgeon will carefully work to divide them as they make the zigzag cuts.
The surgeon will sometimes stitch skin grafts, or transplanted pieces of healthy skin, over the top of the exposed wounds to protect them as they heal. This will also minimize scarring by reducing tension as the wound heals. The surgeon will usually take skin grafts from the child's inner groin area or the back of the upper arm.
They will then wrap layers of bandages around the affected area, or fix it in a cast that will cover and immobilize the corrected toes to protect them from injury as they heal. In total, most surgeries to repair webbed digits take 2–5 hours.
Most children will have to stay in the hospital for a few days after the surgery. There is usually some bruising, swelling, and nail discoloration on the toes. After discharge from the hospital, children are likely to need pain medications as they recover.
In the majority of cases, it is possible to treat syndactyly successfully.
It typically takes a month or so before children can begin to put pressure on the separated toes and 3–6 months before they fully heal from surgery, depending on the extent of the procedure.
As webbed toes can interfere with proper development, lead to disability, and possibly cause self-esteem issues, most insurance plans cover part of the cost of corrective surgery.