Cross Finger Flap. A New Technique

Avulsion injuries of the thumb resulting in volar defects and loss of neurovascular bundles are presented. Treatment should aim at restoration of the skin and pulp with as near normal sensation as possible. A new technique is described using a cross-finger flap or flaps with transfer of the superficial terminal branch of the radial nerve. It is claimed that this gives near normal restoration of sensation to the tactile surface of the thumb. The fingers may be treated in the same way for similar injuries. Avulsion injuries are very common in trauma of the hand. They frequently occur in carpenters using various power driven tools. Particular problems are seen in those injuries where, not only the skin, but also the deeper structures uch as nerves, tendons or joints are involved. One either deals with the full thickness kin defect or undertakes an immediate reconstruction f the lost tissue. When one considers reconstruction, special importance must be given to the provision of skin possessing sensibility of the highest quality. Our primary aim in presenting this paper is to stress the importance of sensibility over the tactile surface of the thumb in the overall function of the hand with particular reference to pinch. The usual methods adopted in the treatment of these injuries are:-1. Local flap procedure 2. Free skin grafts 3. Conventional cross-finger flap 4. Innervated cross-finger flap using the superficial branch of the radial nerve 5. Distant skin flap Each of these techniques has its shortcomings as follows:- Local flaps are rarely feasible and entail the risk of painful scars. These are likely to be sensitive to pressure and interfere with function. There is the temptation when using a local flap to economise to such an extent hat there is a real risk of suturing with undue tension. This may result in partial necrosis aggravating the problem. A local flap should only be done when its success is ensured. Free skin grafts provide unsatisfactory cover in such cases. They tend to be hypersensitive and are very vulnerable to injury. Moreover, the pulp is not replaced giving a poor cosmetic appearance. This may have adverse psychological effects