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What is Syndactyly?
Syndactyly is a common birth defect: the child is born with two fingers (or two toes) stuck together. The fingers can be glued simply to the base or else glued to the end, along their entire length. The two fingers can even have a common nail. This pathology affects one in 2 children. In the vast majority of cases, it is benign and can be corrected by a simple surgical operation, if necessary. Usually, the fingers involved are the middle and ring fingers. More rarely, it can be the ring finger and the little finger, or the index and middle fingers.
In the case of classic syndactyly, which is called skin syndactyly, the two fingers are simply connected by skin. But there are also cases of complex syndactyly, where the bones of the two fingers have fused.
A common form: glued toes and webbed feet
Syndactyly of the toes are even more common than those of the fingers. It is estimated that one in 800 people have one. For the foot, syndactyly almost always concerns the second and third toe, and much more rarely the big toe. Most of the time, the toes are only glued at the base, giving the foot a slightly webbed appearance. This form of syndactyly is often familial.
What is the cause of syndactyly?
The embryo’s fingers form between the 4th and 6th week of pregnancy. At this point, his hand still only looks like a small palette. Normally, some cells disappear spontaneously in order to leave a space between the fingers. But in some cases, this phenomenon does not occur, which will later lead to syndactyly. The origin of this disorder cannot be identified with certainty. In some cases, this is a hereditary transmission but most often, the cause is external : a viral illness, taking medication or exposure to an x-ray.
Syndactyly: surgical treatment sometimes necessary
If hand syndactyly is not managed, the child will have to deal with functional disability : he will have less ease in his movements than if his fingers were completely independent. Besides, aesthetic discomfort is not to be neglected either: the feeling provoked by the vision of syndactyly can vary from compassion to rejection and will be a source of suffering for the child. These problems can be avoided by simple surgery. Syndactyly of the toes, on the other hand, does not cause functional impairment and does not require surgery during the first years of life. If later, once a teenager or adult, the person concerned considers this unaesthetic feature, they may then have recourse to surgery.
Syndactyly: how is surgery performed?
The surgery for simple syndactyly consists of cut the skin to separate the two fused fingers and sew them up individually. If the fusion is restricted to the base of the fingers, a well calculated incision will allow them to be stitched together properly. If the fusion exceeds the first phalanx, it will then be necessary to have recourse to a skin graft which will be sought in the fold of the groin of the child, in the fold of the wrist or in the fold of the elbow.
After the operation, the child will keep a bandage on for a week or two, then he will naturally start to move and use his fingers. Normally, a single operation, performed under general anesthesia and around the age of one year, is sufficient to overcome it. The child does not retain any sequelae. Sometimes one or more additional operations may be necessary as the child grows, for example if the corner of the fingers moves away from the palm.
Namely
For a complex syndactyly where the bones of the fingers are fused, the operation follows the same principle, but in addition, the bone is split in two and the ligaments are repositioned around each joint. This operation requires a little more sustained follow-up.
A special case: amniotic syndactyly
In a child with amniotic syndactyly, the fingers are fused at the end but not at the base. The origin of this pathology is different that of the syndactyly described previously: it is supposed that “amniotic bands” present in the uterus surround the baby’s fingers like strings and make them merge. So far, it is not known which element present in the uterus could play this role. This malformation must be operated on as soon as possible after birth to separate the tips of the fingers. A second operation will follow a little later to correct the corners of the fingers.