Annals of'Burns and Fire Disasters - vol. IX - n. 3 - September 1996

THE TREATMENT OF ELECTRICAL BURNS IN THE VOLAR PART OF THE ADIOCARPAL REGION

Beiba GA.

Clinic of Plastic Surgery and Burns, U.C.H.T, Tirana, Albania

SUMMARY. In electrical bums in the volar part of the radiocarpal region, with damage to the u1nar and radial arteries, it is of great importance to preserve the posterior interosseous artery. It is this artery, together with the dorsal carpal arch and other anastomoses, that ensures vascularization of the hand. A regional anatomical description is given in relation to different stages of the surgical protocol. An evaluation is made of early necrectomy, decompression of the muscle compartment, ligation of damaged vasal stumps, surgical re-exploration, and the closure of wounds with skin grafts. The treatment of electrical trauma in this region of the body is debated on the basis of the description of a number of cases.

Electrical injuries in the radiocarpal region create many problems for both patient and surgeon. The involvement of various anatomical structures and the depth of the lesions not only jeopardize hand function but often raise the question whether to preserve the hand or not. The decision of the surgical staff is a constant source of debate, but if the question were clearly put - i.e., "will the patient accept in this first phase of treatment the hand without function or a prosthesis?" - the discussion could be more rapidly concluded. In fact all our patients have preferred the first alternative. In consultations with them and their families, we have noted that there is usually a strong desire to preserve the hand, even if only for external appearance. This logic seems to be justified, as nobody can readily accept the trauma of amputation of the hand, since it is natural to hope for functional improvement at a later stage.
Apart from the involvement of nervotendinous forniations, vascularization of the hand is compensated when only one of the two arteries of the hand is damaged. This article will consider cases in which although both main arteries were damaged vascularization of the hand was maintained within the normal range. The importance is stressed of the interosseous arterial system, as well as some aspects of surgical treatment.

In the period 1992-1993 we treated eight cases of electrical bums in the radiocarpal region. In three of the cases, in view of the deep tissue destruction, we performed amputation in the upper part of the antebrachial region. In the other five cases the electrical trauma was concentrated in the volar part of the radiocarpal region, with damage to the two main arteries. In one of these five cases the injury was located only in the radiocarpal region, while in the other four the injury also affected other parts of the body (mean BSA, 11.5%). In these five patients (all male, average age 22.4 yr) necrectomy was performed either on the day of admission or the following day.
Each patient required on average three operations:

complete necrectomy of all injured zones, muscular decompression, preservation of posterior interosseous arteries, ligation of damage vasal stumps exploration necrectomy of the radiocarpal region skin graft on the wounds, including the radiocarpal region In two patients, at the end of the operation, we used an autotransplant as a biological dressing, while in the third patient it was necessary to apply an osteosynthesis, as the radiocarpal articulation was open. On discharge, the patients had a consolidated transplant and vascularized but nonfunctioning hands, because of the injury to the nerves and the main flexor tendons. Only some slight extensor movement of the fingers was seen. The mean hospitalization period for the five patients was 63.3 days. At the last follow-up we did not observe any disturbances of the veDolymphatic circulation or the appearance of neurotrophic lesions.

In the event of complete destruction of the radial and ulnar arteries in volar electrical trauma in the radiocarpal region, anatomical considerations suggest that it may be possible to vascularize the hand by means of the interosscous system, and in particular through the posterior interosseous artery. This artery is located in the posterior part of the forearm, and if not affected by the electric current it assumes great importance for the maintenance of vascularization of the hand through the dorsal carpal arch. It is an artery of considerable diaiiieter (0.9-2.7 mm)l and the blood flow through it is potent, also because the circulation of blood ceases in the radial and ultiar arteries, while the blood flow is unchanged in the brachial artery in the antecubital fossa.
Absence of injury to both the interosseous arteries creates the possibility of uniform distribution of blood in the hand. In most cases the volar location of the trauma prevents the functioning of the anterior interosseous artery, leaving the hand dependent on the posterior artery. In this description of the vascular anatomy of blood circulation from the origin in the posterior interosseous artery as far as the fingers, we shall also consider problems of a surgical nature.
The common interosscous artery springs frotn the ulnar artery at the level of the radial tuberosity and divides immediately into the posterior and anterior interosseous arteries. The posterior artery passes below the supinator muscle and enters the posterior compartment of the forearm. The entry point is situated between the middle and proximal thirds of the line from the lateral epicondyle to the radioulnar articulation.',' The posterior interosseous artery is accompanied on its way by the posterior interosseous nerve and two veins. The pediele is situated throughout its length in the septum between the extensor digiti minimi and extensor carpi ulitaris muscles.
At the wrist the posterior interosseous artery anastomoses with the dorsal carpal arch and the vascular plexus around the ultiar head (Fig. 1).' Up to this level arterial circulation is of axial type, like radial and ulnar circulation, while beyond it the anastomosis is dominant. This we can consider an intermediate mechanism to reach the palmar arches, an absolute necessity for digital vascularization. Thus, from the dorsal carpal arch spring the dorsal metacarpal arteries, which anastomose with the palmar rnetacarpal arteries in the distal level of the metacarpus. The palmar metacarpal arteries are branches of the deep palmar arch and at the same time anastomose with the digital artery of the superficial palmar arch .

1. Dorsal carpal arch.

2. Anastomosis between dorsal metacarpal arteries and palmar metacarpal arteries.

3. Anastomosis between palmar metacarpal arteries and common digital arteries.

The method of surgical treatment makes use of certain techniques whose function is to preserve vascularization of the hand. Immediate necrectomy accompanied by decompression of the muscular compartments',' has to be performed as soon as the patient's condition permits it. One aim of this procedure is to preserve the pronator quadratus muscle and, if this is not damaged, to stimulate carpal anastomosis of both interosseous arteries, and also to regulate the posterior interosseous circulation when this functions alone. Decompression in the posterior compartment of the forearm and the practising of small skin incisions are not justified, as these procedures would irreparably damage the vascularization of the hand. We are of the opinion that the preservation of the septocutaneous arteries in this region also contributes to hand vascularization. During the same surgical operation, we ligate the radial and ultiar arteries in order to prevent late acute haemorrhage.

As with all electrical burns, the surgeon is right to perform new local explorations for the realization of full necrectomy, thus creating conditions for quick granulation. Excision as far as the carpal bones, the opening of articulations and the removal of a carpal bone can all be performed without hesitation, when the indications are complete. Although we are working on a bony plane, we have observed that granulation is not late - on the contrary, there may be hypergranulation if covering is delayed. Finally, closure of the wound is performed with a middle-thickness transplant.
With regard to this last aspect of the wound closure by epidermo-dermic transplant, we believe, taking the whole surgical protocol into consideration, that this is the best technique. In the literature there are discussions of the comparative merits of epidermo-dermic transplants and immediate flaps.'-' We however would stress that the localization of electrical burns in the radiocarpal region prevents good flap transfer. In conclusion, we underline that electrical burns of the radiocarpal region must be analysed individually with a view to saving the extremity. We have not entered into the general problems that such burns create in the patient. According to statistics a certain proportion of burn patients suffer orthopaedic traumas,' while our electrical burn patients presented concussion caused by high falls. The overall treatment of such patients is generally successful -satisfactory for the surgeon and acceptable for the patient.

RESUME. UAuteur soutient l'importance, dans les brûlures électriques de la partie palmaire de la région radiocarpienne, avec des lésions dans les artères cubitale et radiale, de préserver l'artère interosseuse postérieure. Cette artère, avec le réseau artériel carpien dorsal et d'autres anastomoses, assure la vascularisation de la main. Après avoir décrit l'anatomie régionale par rapport aux phases successives du protocole chirurgical, l'Auteur évalue la nécrectomie précoce, la décompression du compartiment musculaire, la ligature des moignons vasculaires lésés, la réexploration chirurgicale, et la réparation des lésions avec des greffes cutanées. Enfin il considère le traitement des traumatismes électriques dans cette région du corps à la lumière de la description de divers cas.

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