Congenital syndactyly is a malformation of the hand with a high incidence, which is an abnormal connection of adjacent fingers, and about half of the patients have bilateral symmetrical hand malformation;
The clinical classification of syndactyly is based on the tissue structure of the syndactyly
①Simple syndactyly: only the skin and connective tissue of adjacent fingers are connected, and the skin between the fingers has different widths, and the X-ray shows clear boundaries between the syndactyly, so it is also called soft tissue syndactyly.
②Complex syndactyly: In addition to continuous skin and soft tissue connection between two or more fingers, there is also fusion between finger bones, or neurovascular and muscular tendon connection, so it is also called bony syndactyly;
The degree of juxtaposition is divided into
①Complete syndactyly: from the base of the adjacent fingers to the tip of the fingers are completely connected.
(2) Incomplete syndactyly: only part of the adjacent finger is connected.
③Composite syndactyly: the syndactyly is combined with other deformities, such as acral syndactyly, short syndactyly, split syndactyly, multifidus syndactyly, and annular sulcus syndactyly. Apert syndrome is also characterized by multiple syndactyly, and the hand deformities include unilateral shortening of the index, middle and ring fingers, multiple simple incomplete syndactyly, and hand hypoplasia. Qixing Zhou, Department of Plastic and Reconstructive Surgery, Wuhan Women’s and Children’s Health Care Center
The goal of surgery is to restore hand function and improve morphology, and to prevent or minimize postoperative sequelae. Although juxtaposition is not a very complex procedure, it is often not treated as well as it should be because the principles and techniques are not taken seriously. Preoperatively, the development, deformity and fusion of the finger bones should be understood, and x-rays should be taken routinely. In young infants, there is not enough ossification of the finger bones, and the fusion of the finger bones is not seen on the X-ray, but sometimes the cartilage connection of the finger bones is seen intraoperatively, and whether the finger bones are fused or not has different requirements for flap design and skin implantation.
Timing of surgery
The timing of treatment for syndactyly should be based on the form and degree of syndactyly, the general health of the child, the safety of anesthesia and the parents’ requirements.
(1) For simple incomplete syndactyly with 2 or 3 fingers, the operation is simple and does not require long-term fixation after the operation. The parents of the children choose early surgical treatment because, in addition to striving for better functional recovery, psychological health development is also a major influencing factor;
(2) types of syndactyly, radial or ulnar syndactyly because of unequal fingers restrict each other’s activities and affect the development, too long can make the fingers flexion contracture, rotation deformation, should be operated within a few months after birth (3m ~ 6m). The development of the fingers (especially the thumb and index finger) should be brought closer to the physiological state as early as possible, because angular, rotational and flexion deformities may occur. These deformities are difficult to correct and prevention of these deformities is preferable to the possible movement and contracture of the distal phalanges. In particular, such patients often require multiple surgeries, and choosing the timing of surgery too late may affect the patient’s admission to daycare or school; (3) complex juxtaposed fingers involve the fusion of skeletal components, with more vascular, neural and tendon variants, and surgery at too young an age is more difficult and risky to perform. Therefore, surgery should be performed after 6 months of age;
(4) Complete syndactyly of more than two fingers requires staged surgical correction, and the treatment period is long and should not be too late. It is safer to operate on multiple fingers in stages and not to separate multiple fingers at one time to prevent vascular malformation and necrosis of the separated fingers, but to release the marginal fingers first and then release the other fingers after 6 months;
(5) For multiple finger incomplete juxtaposition, if the surgical technique is skillful, it is possible to separate all the fingers at once, paying attention to the protection of the intrinsic blood vessels.
Thorough finger splitting
When performing a finger-splitting operation, the fingers should be completely separated to the base of the normal finger web. If the finger webs are not completely separated, the finger will remain partially united. A normal web should have a sloping skin fold of significant width and length, covering 1/3-1/2 of the length of the proximal phalanx.
Reconstruction of the finger webs
In a normal adult, the finger webs start from the dorsal aspect of the distal metacarpal head and run in a slope towards the palm, connecting to the palmar skin at the transverse palmar finger line. There are many types of finger web reconstruction, such as triangular flap, rectangular flap, V-tip flap, and bipedal flap, etc. Short procedure, simple flap design, and minimal recorrection probability are the main criteria for evaluating the merits of the procedure. The flippers are deepened and widened by 0.3~0.5 compared to the adjacent normal flippers to allow room for growth, thus reducing the possibility of shallow flippers and even incomplete syndactyly after growth and development of the child.
Serrated incision and skin grafting
The skin between the juxtaposed fingers should be cut in a serrated pattern, avoiding a straight incision, otherwise, a linear scar contracture will be formed. When designing a serrated flap, the site of the flap should be designed according to different situations, and usually the flap should cover the joint area as much as possible. The traumatic surface of the syndactyly should not be forced to close under tension, but should be grafted with a full-thickness skin flap, so as not to cause increased scar widening or local skin necrosis, or even total finger necrosis.
Syndesmosis with fused end phalanges
When separating the malleolus, a skin flap and a fascial flap of subcutaneous tissue should be cut in the finger belly at the same time and staggered to cover the two bony exposed traumas respectively, paying attention to their blood circulation; then the skin should be implanted on the subcutaneous tissue flap, and the pressure packing force should not be too large to avoid necrosis of the fascial flap caused by excessive pressure. The end bone exposure needs to be covered by local flap, and if there is soft tissue covering around it, it can also be repaired by skin grafting.
Postoperative treatment
Postoperative Bactrim is applied externally to the affected area without packing, thin cotton strips of oil gauze are wrapped around the affected finger, gauze bandages are wrapped with appropriate pressure, small splints are fixed in the straightened position of the finger, medication is changed 2-3 weeks after surgery, sutures are removed, and active functional exercise of the finger is performed.