The brachioradialis myocutaneous flap

M. F. LAI, B. V. KRISHNA and A. D. PELLY

Plastic Surgery Unit, Prince of Wales Hospital, Randwick, Sydney, Australia

Summary -The vascular anatomy and the cutaneous territorial definition of the brachioradialis myocutaneous flap has been studied by cadaver dissection and intra-arterial injection of methylene blue dye.

A case is presented in which a proximal brachioradialis myocutaneous flap, based on the vascular pedicle arising from the radial recurrent artery just distal to the elbow level, was used to cover an exposed open elbow joint.

The advantages and disadvantages of this flap are briefly discussed.

The use of muscle flaps in reconstructive surgery can be traced back to Tansini’s report in 1896 of the latissimus dorsi flap in breast surgery. Little further interest was shown or progress made in this field until the last decade since when an increasing number of new muscle flap procedures have been published with a precise definition of the vascular anatomical basis of each flap.

In a recent paper, John Lendrum (1980) from Manchester. reported the use of the proximal part of the brachioradialis muscle to cover a compound fracture dislocation of the elbow, but the vascular anatomy and territorial limits of the flap were not described. Faced with an almost identical clinical problem we decided to study in detail the vascular anatomy based on ten cadaver dissections and dye injection studies.

Anatomy

The brachioradialis is the most superficial muscle on the radial side of the forearm, forming the lateral border of the cubital fossa. It arises from the upper two-thirds of the lateral supracondylar ridge of the humerus and from the front of the lateral intermuscular septum. The muscle fibres end in a flat tendon above the mid-forearm which is inserted into the lateral aspect of the lower end of the radius. The nerve supply comes from the radial nerve (C5 and C6) and its action is to flex the elbow, especially in mid-pronation.

In our dissections to define precisely the blood supply to the brachioradialis muscle vascular pedicles from the radial recurrent and radial arteries were identified. A vascular pedicle of significant size came from the radial recurrent artery close to its origin from the radial artery (Figs. 1 and 2). Smaller inconsistent branches

Fig. 1 Anatomical dissection to show the rudlal recurrent artery (marked by a loop of thread) arising from the radial artery. Note the sizable muscular branch to the brachic>- radialis branching off immediately and the several smaller branches and the radial reccurent artery passing upwards between the brachioradialis and brachialis rnu~cles.

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Fig. 2 Diagrammatic representation of the site and origin of the radial recurrent artery and its branch to the brachio- radialis muscle.

were given off as the radial recurrent artery coursed between the brachialis and brachio- radialis to anastomose with the profunda brachii artery. Injection of methylene blue dye into the radial recurrent artery revealed the vascular territorial limits of the brachioradialis myocutane- ous flap (Figs. 3 and 4). This covers approxi- mately the posterolateral lower half of the upper arm and the lateral upper third of the forearm. Thus by preserving the vascular supply from the radial recurrent artery (through its main vascular pedicle and its smaller inconsistent branches) the proximal part of the brachioradialis muscle with or without its overlying skin may be raised as a flap and transposed to cover the exposed elbow.

Case Report

A man aged 72, a known asthmatic, was admitted with full-thickness burns over the right chest wall, shoulder, axilla, arm and upper forearm, involving 15 yO of the total body surface. Following initial resuscitation, removal of sloughs and skin grafting we were left with the problem of an exposed right elbow joint open on its postero-lateral aspect (Fig. 5).

After excision of some residual sloughs the proximal part of the brachioradialis muscle with a random- pattern cutaneous extension was raised, based on the radial recurrent artery. The distal limit of the flap

reached mid-humeral level (Fig. 6). The nerve to the brachioradialis was sacrificed in the process. This flap was then transposed over the exposed elbow joint and the donor defect was split-skin grafted (Fig. 7). The post-operative course was uneventful (Fig. 8).

Discussion

This flap allowed us to cover the elbow joint in a one-stage procedure. It avoided the need for a two-stage lateral chest flap which might have caused shoulder stiffness, increased the risk of axillary contracture and would have restricted chest movements in this asthmatic patient.

There are however certain disadvantages. When used as a myocutaneous flap the patient is

Fig. 3 An injection of methylene blue dye in the cadaver indicates the skin vascular territorial limits of the brachio- radialis myocutaneous flap.

THE BRACHlORADIALIS MYOCUTANEOUS FLAP

Fig. 4 Another view to show the proximal and distal cutaneous territorial Ilmits of the brachioradialis myw clltanwus flap.

Pig. 5 An open exposed elbow joint following full-thichness burn\.

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Fig. 6 A brachioradiahs myocutaneous flap has been raised. based on the radial recurrent artery. Note the donor defect on the upper limb.

Fig. 7 The brachloradialis myocutaneous flap has been transposed to cover the exposed elbow joint. The Ilap donor defect has been skin grafted.

Fig. 8 Four weeks later.

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left with only split-skin graft cover over the radial nerve and an unsightly contour defect at the flap donor site. These objections would obviously be less valid if the brachioradialis muscle alone was used.

Theoretically either the proximal or distal parts of the brachioradialis muscle based on the radial recurrent artery could be used to cover defects in the cubital fossa (Fig. 9). Medial epicondylar cover might be difficult due to tension and/or torsion of the vascular pedicle. To date we have no clinical experience of these possible applications.

Lendrum, J. (1980). Alternatives to amputation. Annuls of’ the Royal College qf Surgeons of England, 62, 95.

Tansini, I. (1896). Nuovo process0 per I’amputazione della mammella per cancre. Reformn Medica, 12, 3.

The Authors

M. F. Lai, FRCSEd, FRACS. B. V. Krishna. FRACS, Microsurgery Research Fellow. A. D. Pelly. FRCS, FRACS, Consultant Plastic Surgeon.

Request for reprints to: Mr M. F. Lai, FRCSEd, FRACS, Plastic Surgery Unit, Prince of Wales Hospital. Randwick, Sydney. Australia 203 I.

Fig. 9 Cadaver dissection to show the possible application of this muscle flap to cover the cubital fossa.