Webbed Fingers and Toes (Syndactyly)

Overview

Syndactyly is a disorder in which children are born with fingers that are fused or webbed. Approximately half of all children with syndactyly have it in both hands (bilateral). Syndactyly typically affects the fingers. It occasionally affects the toes, although not as frequently.

While syndactyly can occur between any two or more fingers, it most commonly occurs between the middle and ring fingers. A stretch of skin that resembles webbing may join the fingers. In certain situations, the fused digits may resemble a single finger.

Syndactyly is a rather frequent condition. It affects around one in every 2000 infants. Boys are more likely to be affected than girls, and white children are more likely to be affected than Black or Asian babies.

A baby's hands develop in the shape of a paddle during pregnancy and then divide into individual fingers. This occurs extremely early in pregnancy, between the sixth and eighth weeks. If two or more fingers do not separate at this period, syndactyly occurs.

Syndactyly frequently runs in families. Children with syndactyly inherit the disorder from one or both parents.

Surgery is used to separate the linked fingers in syndactyly. Your child will most likely have this surgery between the ages of one and two.

What is Webbed Fingers and Toes (Syndactyly)?

The medical term for having webbed fingers or toes is syndactyly (digits). It is one of the most frequent birth abnormalities that affects the hands and feet of neonates.

Finger syndactyly is a type of congenital hand difference.

Your doctor will most likely identify your kid with syndactyly shortly after birth. It is handled differently depending on which of your baby's fingers or toes is afflicted and how they are fused together.

Syndactyly vs Polydactyly

Both syndactyly and polydactyly are congenital abnormalities that affect the hands and feet of newborns.

Syndactyly occurs when two (or more) of your child's fingers or toes fuse together, forming webbing. Polydactyly is characterized by the development of additional fingers or toes on your baby's hand or foot.

Polysyndactyly is a combination of both diseases that results in newborns with webbed and additional digits.

All of these diseases are often detected at birth and treated as soon as it is safe to do so. They normally have no long-term effects on newborns once they've been treated.

Who Does Webbed Fingers and Toes (Syndactyly) Affect?

Any newborn baby can be affected by syndactyly. Newborns who are assigned male at birth are twice as likely as babies who are assigned female at birth to have syndactyly. White newborns are more common than other ethnicities to be born with syndactyly.

If you have a family history of genetic diseases, your kid is more likely to have syndactyly, especially if any of your close family (such as grandparents, parents, or siblings) were born with merged fingers or toes.

Being born with syndactyly does not preclude your child from developing developmental abnormalities or other issues.

How Common is Syndactyly?

Syndactyly affects around one in every 2,000 newborns born each year. It is more frequent in the toes than in the fingers.

Half of all syndactyly instances are bilateral, meaning they affect fingers on both hands or both feet.

Even though it is one of the most frequent birth malformations, these disorders are still very uncommon. If you're worried about your baby being born with a birth defect, talk to your physician.

How Does Syndactyly Affect My Baby’s Body?

If your baby's digits are not separated, he or she may have difficulty utilizing them as they grow. This is particularly true for fingers that have been fused together.

Because most cases of syndactyly are treated when your child is very young (around a year old), they may never experience any effects or even be aware that they have it.

If your child is diagnosed with a genetic ailment or other birth defect at the same time as syndactyly, those disorders may have a long-term influence on their growth and development.

Types of Webbed Fingers and Toes (Syndactyly)

Your provider may use a few different terms to describe your baby's syndactyly in his or her fingers or toes. Which kind they have is determined by which of their fingers or toes is impacted — and how much of their digit is fused.

Simple syndactyly refers to fingers or toes that are merely joined by skin. Because of complex syndactyly, your child's bones, nerves, and blood vessels are all fused together. Simple syndactyly is more common than complex syndactyly.

Furthermore, your child may have complete or incomplete syndactyly. Complete syndactyly implies that their digits are fused together all the way from the base to the nailbed. Incomplete syndactyly indicates that the fusion only goes down a portion of their digit.

These terms are usually more for your provider to use to describe the syndactyly. No matter which type your baby is diagnosed with, your provider will explain how they can treat it.

What Causes Syndactyly?

Syndactyly is caused by changes in your baby's DNA during development. The biological building elements that parents pass on to their offspring are known as genes. They carry instructions for each cell in your body's development and function.

Anything that disrupts or modifies a gene while your kid is developing might cause physical changes. Sometimes we don't notice these alterations, and other times they create problems like syndactyly and other birth disorders.

If anything disrupts the genes responsible for the development of your baby's limbs, hands, and feet, they may be born with syndactyly. Environmental influences, as well as genetic abnormalities, can interfere with these genes (things that happen to or around a pregnant person).

Genetic disorders that frequently cause syndactyly include:

• Down syndrome.
• Apert syndrome.
• Poland syndrome.

Syndromes Associated With Syndactyly

Syndactyly can be seen alone or in conjunction with other anomalies such as polydactyly, cleft hands, ring constrictions, or craniofacial disorders.

The most well-known craniofacial condition is Apert syndrome. Poland syndrome is another possibility, in which the pectoralis muscle anomaly is present in conjunction with symbrachydactyly or other ipsilateral upper extremity defects. Syndactyly can be coupled with constriction band syndrome, although the origin of the syndactyly is different.

• Apert syndrome

Apert syndrome, also known as acrocephalosyndactyly, is an uncommon birth defect that affects one in every 160,000-200,000 live births. Apert syndrome is distinguished not only by the typical face deformities, but also by the concomitant upper- and lower-limb malformations. The abnormalities in the hands are mirror reflections of one other, and they share four characteristics:

• Radial deviation of a short thumb as a result of an abnormally shaped proximal phalanx (i.e., delta phalanx)
• Complex syndactyly of the index, long, and ring fingers
• Symbrachyphalangism of the central segments of the index, long, ring, and small fingers
• Simple syndactyly of the web space between the ring and small fingers

The web space between the thumb and index finger is varied, and the level of syndactyly at this web space is used to classify Apert syndactyly into three categories, as shown below.

Type I is the most prevalent and the mildest of the three. As a result of the proximal phalanx's delta phalanx, the thumb is foreshortened and correlated with radial clinodactyly. The initial web space is shallow, while being independent from the index finger.

A complex syndactyly includes the index, long, and ring fingers because of osseous or cartilaginous union of the distal phalanges. Simple syndactyly of the small and ring fingers is present; this syndactyly may be complete or incomplete. The distal interphalangeal (DIP) joint of the small finger is well formed and functional. Type I hands are often referred to as spade hands. 

Type II is more severe, with a simple partial or full syndactyly of the thumb with the index ray and no osseous union. The thumbnail matrix is still distinct from the index fingernail. The palm of the hand is big and concave. Type II has a more extensive bony union of the distal phalanges of the index, long, and ring fingers than type I. The ring finger-small finger syndactyly is simple but complete. Type II hands are sometimes known as mitten hands or spoon hands.

Type III is the most severe and, fortunately, the rarest variety. All five fingers have a tight osseous or cartilaginous union. All five nail plates are linked together, and longitudinal ridges suggest distinct underlying distal phalanges. The thumb and index ray are indistinguishable. Although linked by a shared fingernail, the tiny finger lacks an osseous union at the distal phalanx and maintains a basic but complete syndactyly. Metacarpal synostosis of the small and ring finger rays is usually present.

Type III hands have been termed rosebud or hoof hands. Radiographs are difficult to obtain and interpret because of the overlap of osseous structures.

• Poland syndrome

Poland syndrome is a sporadic congenital abnormality defined by the loss of the sternal head of the pectoralis major muscle, hypoplasia or aplasia of the breast or nipple, and axillary hair and subcutaneous fat shortage. There may be associated rib cage and ipsilateral upper extremity anomalies. Anomalies of the hand and fingers include symphalangism, syndactyly with hypoplasia, brachydactyly, and finger aplasia.

• Constriction band syndrome

The syndactyly observed in constriction band syndrome (also known as amniotic band syndrome) is not the product of embryonic differentiation failure. The fingers are already developed in this condition, and the injuries caused by the restricting amniotic bands force the fingers to heal together at the site of damage, resulting in post-injury syndactyly. The involvement might be little, with only a rudimentary tiny skin bridge joining the two fingers.

How Syndactyly is Diagnosed?

Despite the fact that many patients with syndactyly have been reviewed by numerous experts and referred by their primary care doctor, the hand surgeon should also collect a detailed prenatal, postnatal, and familial history. Aside from the hand, the head, face, chest, and lower extremities should also be inspected for abnormalities.

The hand evaluation should proceed systematically, as follows:

• Note and document the number of digits present, the level of web involvement, the length of the finger, and the appearance of the fingernails.
• Often, photographing or drawing a picture of the hands during the initial visit is helpful.
• Passively move the fingers to check for bony union; differential mobility occurs only if there is no underlying bony union. Fingernail fusions are frequently connected with bone union, and a wide fingernail may also imply latent polydactyly.
• The extent of the anomaly of tendons and neurovascular structures reflects the complexity of the syndactyly; in a simple complete or complex syndactyly involving only the distal phalanx, the underlying tendon and neurovascular structures are usually normal; however, in a person with brachysyndactyly or complicated syndactyly, the bifurcation of the nerves and digital vessels may be located more distally, or only one side may be present.
• Always obtain radiographs to help identify any other anomalies (e.g., bony synostosis, delta phalanx, or symphalangism).

X-rays and other imaging tests) e.g.MRI) may be done to examine the underlying anatomy of your child's hands and determine if the bones are joined.

Other regions of the body may require genetic testing and imaging to uncover relevant genetic disorders and abnormalities.

How is Syndactyly Treated?

The fused digits are surgically separated to treat syndactyly. Most newborns are treated for syndactyly around the age of a year.

Your child's fingers or toes will be separated by a surgeon (including any fused bones and other tissue). A skin graft is frequently performed to cover the split digits.

After surgery, your child may need to wear a splint or cast on their surgically repaired hand or foot to support their split fingers or toes. They may also require physical therapy to ensure that their hand or foot regains strength and can function normally following surgery.

Your provider or surgeon will advise you on the type of surgery your kid will require, as well as what you will need to do once their joined digits are separated.

• Nonsurgical syndactyly treatment:

Some children with minor syndactyly may never require surgery. This is mainly reserved for syndactyly affecting the toes. Your provider will determine if your kid need surgery to separate their digits.

It is uncommon for children to not require syndactyly surgery on their fingers since anything that limits their capacity to move can have an impact on the overall function of your child's hand.

Postoperative Care

The upper extremity is wrapped in a thick bandage that has been well-molded. A substantial amount of antibiotic ointment is administered directly to the skin graft, and the incisions are then covered with a nonadherent dressing material like Adaptik. (Because petroleum-impregnated cotton gauze products dry quickly and can adhere to the skin grafts with the first dressing change, the surgeon may wish to avoid them.)

Following this, gently lay cotton fluffs within the web space. The upper extremity is then covered with a thick, well-padded long arm dressing and strengthened with a fiberglass long arm splint. Absorbable sutures and adhesive strips are used to seal the skin-graft donor site, which is then covered with gauze and clear cellophane ad

The parents are instructed to remove the skin-graft donor site dressing on postoperative day 3. They may then start bathing the child and can get the donor site wet, with encouragement to wash this area with soap and water. The long arm splint is kept in place and is removed at 2 weeks. The utmost care should be taken when the dressing is removed. If there is any concern about the possibility of loss of the skin graft with an early dressing change at 2 weeks, the dressing is left in place for 3 weeks.

If any concern exists about the child being unable to tolerate a dressing change in the office, the dressing is removed intraoperatively, and the parents are directed to perform daily wound care. The parents change the dressing once a day for 2 weeks, gently washing their hands before each dressing change. During these changes, an antibiotic ointment is applied with a cotton swab to gently agitate any dried blood or residual drainage that is adhering to the sutures. The web spaces are dressed with 2 × 2 cotton gauze, laid into the web space to prevent scar adhesions and synechiae. This dressing is then reinforced with 2-in. (5-cm) gauze.

Stockinettes are then applied over the arms and secured to the patient's shirt at the shoulder with safety pins to prevent the patient from chewing or taking the dressing off. If the bandages stick to the sutures or to the wound, the parents are instructed to pour warm water with peroxide as needed to lift the dressing off atraumatically. The parents are instructed about scar management starting 6 weeks after surgery.

Follow-up Care

The hand surgeon will check your child two weeks after surgery and again six weeks afterwards. Your child's long arm cast will be removed during the two-week checkup. The majority of children will not require splinting or hand rehabilitation.

Throughout early childhood, your child will need to return to the hand surgeon for numerous annual visits to ensure she is developing proper hand function. This is especially important when she learns new abilities like writing and athletics.

Conclusion

The medical term for webbed or conjoined fingers or toes is syndactyly. Syndactyly is the most common limb malformation, affecting approximately one in every 2,000-3,000 children born each year.

Syndactyly can be classified as:

• Simple, where fingers are joined by skin and soft tissue.
• Complex, where the fingers are joined by bone.
• Complete, where the whole fingers are fused together to the tips.
• Incomplete, when fingers are joined only partially.

Most children's affected fingers are simply linked by skin; it is uncommon for the bones to be fused together.

Webbed fingers, if left untreated, can affect finger growth, hand function, and dexterity.