The Thoracoacromial/Cephalic Vascular System for Microvascular Anastomoses in the Vessel-Depleted Neck

Objective  To review our experience with use of the thoracoacromial/cephalic (TAC) system in the free flap reconstruction of complicated head and neck defects.

Design  Case series.

Setting  Tertiary care referral center.

Population  A consecutive sample of 11 patients requiring free flap reconstruction of head and neck defects using the TAC system for microvascular anastomoses was identified by medical chart review.

Intervention  Free flap reconstruction of complicated defects of the head and neck using the TAC vascular system for microvascular anastomoses.

Main Outcome Measures  Free flap survival and microvascular thrombosis.

Results  Of 11 patients using TAC anastomoses, all had complete survival of free flaps. No complications related to anastomotic failure were identified.

Conclusions  The TAC system provides a reliable source of undisturbed vessels when cervical vessels are unusable or absent.

FREE FLAP reconstruction of defects of the head and neck has become a commonly used technique. The presence of adequate blood vessels for anastomoses is vital to the success of these procedures. However, in patients with previous ablative or reconstructive surgery, extensive trauma, wide surgical excisions, or irradiated tissues, it may be difficult or impossible to find suitable vessels in the cervical area.

Sporadic studies in the literature have looked primarily at techniques to facilitate venous anastomoses in the vessel-depleted neck. Several articles have looked at the cephalic vein as an alternative vessel for venous anastomoses.^1-3 There is a paucity of literature on techniques for arterial anastomoses in the vessel-depleted neck and in particular on the use of the thoracoacromial system as a reliable arterial source for free flap reconstructions of the head and neck.

We reviewed our experience with use of the thoracoacromial/cephalic (TAC) system in the free flap reconstruction of complicated head and neck defects and found this to be a reliable and invaluable technique. The anatomy and application of this technique are discussed.

Eleven patients requiring TAC anastomoses were identified through review of operative records. These patients' medical charts were evaluated to identify patient background, indication for surgery, previous surgical or medical interventions, type of resection, type of reconstruction, use of vein grafts, operative complications, anastomotic difficulties, postoperative complications, and free flap survival.

After the initial portion of the procedure was completed, access was gained to the TAC system by creating a curved incision over the area of the deltopectoral groove in such a fashion as to preserve and stage the area of the deltopectoral flap (Figure 1). Skin and fascia were then elevated as if elevating the deltopectoral flap until the deltopectoral groove and the lateral aspect of the clavicular head of the pectoralis major muscle were exposed. Dissection was then taken into the deltopectoral groove, where the cephalic vein was identified. The vein was dissected as far into the arm as was necessary to allow transposition over the clavicle and into the neck for tension-free anastomoses.

Attention was then turned to dissection of the thoracoacromial system. A horizontal incision was made across the pectoralis muscle, dividing its lateral attachment to the clavicle (Figure 1). Careful dissection in the plane deep to the pectoralis major muscle and superficial to the pectoralis minor muscle was undertaken to identify the main trunk of the thoracoacromial system and its takeoff from the axillary artery. Usually, several branches of the thoracoacromial artery can be identified and preserved for anastomosis. In an effort to preserve the viability of the pectoralis major muscle flap, the pectoral branch was usually preserved if an alternative branch was of suitable dimensions.

If a pectoralis major muscle flap had been elevated during previous surgery, then the pectoral branch of the thoracoacromial artery often could be identified on the surface of the elevated pectoralis muscle. This branch was then traced retrograde to its origin at the thoracoacromial artery. The pectoral branch, thoracoacromial artery, or one of the other identified branches was then used for anastomoses.

Patient backgrounds are summarized in Table 1. Table 2 details previous surgical interventions. Table 3 indicates the reconstruction method and vascular supply used. Of 11 patients using the TAC anastomoses, all had complete survival of free flaps. No complications related to anastomotic failure were identified. Two representative patients are described in greater detail in the following subsections.

This patient originally had cutaneous squamous cell cancer on the right shoulder and neck. The tumor was excised, and he experienced recurrence approximately 1 month later and subsequently underwent Mohs surgery. A recurrence was again experienced approximately 3 months later. At that time, he was referred to our institution (The Mount Sinai Hospital). On examination, the patient had a large right neck mass with a fungating appearance. No other abnormalities were noted. The patient had an extensive resection with neck dissection, leaving a large defect (Figure 2). The defect included complete exenteration of the posterior triangle to the level of the brachial plexus, including removal of all usable posterior triangle vessels. A planned delayed reconstruction after final pathology results were obtained was then undertaken using a combined parascapular fasciocutaneous and latissimus dorsi myocutaneous free flap. A pedicled flap reconstruction was considered, but the size of the defect required free tissue transfer for adequate coverage. Anastomoses were performed to the thoracoacromial artery and cephalic vein, which were used preferentially owing to their proximity to the ablative defect. The results of this reconstruction are demonstrated in Figure 3.

This patient was originally treated with an organ preservation radiation therapy and chemotherapy protocol for laryngeal cancer. He subsequently developed evidence of recurrent and persistent laryngeal cancer. He then underwent salvage total laryngectomy and bilateral selective neck dissections with placement of a pectoralis major muscle flap over the pharyngeal closure. After surgery, the patient developed a pharyngocutaneous fistula with wound breakdown and exposure of the carotid artery. A formal pharyngostome was created with cervical skin flaps. This closure subsequently broke down with exposure of the carotid artery. A superiorly based trapezius myocutaneous flap was then brought into the neck for carotid coverage, and the skin from this flap was used to recreate a pharyngostome. This flap pulled away from the posterior pharyngeal wall, again leading to carotid artery exposure. The wound was treated conservatively with packing, and the patient was scheduled for reconstruction of the pharynx using a gastro-omental artery free flap. At the time of surgery, extensive exploration of the neck to find adequate blood vessels for anastomosis revealed that the previous neck dissection, radiation therapy, and salivary leak had left no reliable vasculature in the ipsilateral or contralateral neck. This procedure was performed using the TAC system for vascular supply (Figure 4). The patient did well after surgery.

Reconstruction of the head and neck in the presence of a vessel-depleted neck is becoming a common problem with the increased use of free flaps. The cephalic vein has recently been described as a "lifeboat" for head and neck reconstruction.¹ Horng and Chen¹ reported their experience with 3 patients requiring free flap reconstruction. The cephalic vein was the recipient vein in 2 cases and was used in continuity with a radial forearm flap in a third case. A later study² presented 11 cases of cephalic vein transposition for head and neck reconstruction with excellent results. The advantages of the transposed cephalic vein technique include the ability to span long distances in the head and neck, thereby eliminating the need for vein grafts and anastomosing to a vessel outside an irradiated field.⁴ In addition, the cephalic vein is often an excellent size match for microvascular anastomoses. In our series, the cephalic vein was used preferentially because of its simple dissection and the length of the vessel that allows for transposition over the clavicle to reach virtually any area of the ipsilateral neck.

The anatomy of the cephalic vein has been described in detail elsewhere.³ The radial continuation of the dorsal venous arch forms the origin of the cephalic vein. The cephalic vein then crosses the tendon of the extensor pollicis longus and ascends across the radial border of the wrist. The cephalic vein next turns anteriorly to parallel the anterior border of the brachioradialis muscle and the radial artery and its venae commitantes. In the antecubital fossa, the median cubital vein obliquely ascends as a major branch to connect with the basilic vein and the deep venous system. This anastomotic network provides the various options for venous outflow for the radial forearm flap. The cephalic vein next follows the lateral bicipital groove to enter the deltopectoral groove between the respective muscles. The cephalic vein usually accompanies the deltoid arterial branch of the thoracoacromial axis, where it pierces the brachial fascia to leave the subcutaneous level. Deep in the deltopectoral triangle, the cephalic vein perforates the costocoracoid membrane at the upper border of the pectoralis minor muscle to empty finally into the axillary vein. The cephalic vein has been reported to cross anterior to the clavicle to penetrate to cervical fascia and end in the external jugular vein.³

To our knowledge, there have been no previous reports of the thoracoacromial system being used as an arterial source for free flap reconstruction of the head and neck. Seikaly et al⁵ recently detailed the thoracoacromial axis as a vascular supply for the clavipectoral osteomyocutaneous free flap. Other articles^6-8 have commented on the thoracoacromial axis as a recipient vascular supply for reconstruction of other areas, including the breast and thoracic esophagus.

The anatomy of the thoracoacromial system has been well described.⁹ The thoracoacromial artery consistently arises as a branch off the second part of the axillary artery. It classically divides into 4 named branches: the pectoral, deltoid, clavicular, and acromial arteries. The thoracoacromial venous system generally mirrors the arterial branching, although more variability has been reported. Through cadaver studies,⁹ the diameters of the branches of the thoracoacromial arterial system have been found to range from 1.2 to 2.4 mm; the diameter of the thoracoacromial arterial trunk was found to have a diameter of 2.5 to 7.0 mm. In our series, the branches of the thoracoacromial arterial system could be dissected distally to achieve enough length to transpose the artery over the clavicle into the neck while maintaining an adequate lumen for anastomosis.

The pectoral branch of the thoracoacromial artery is the main vascular pedicle on which the pectoralis major muscle flap is based. This becomes a consideration when using the TAC system for 2 reasons. First, when a pectoralis muscle flap has not been elevated during a previous procedure, thought must be given to the possibility of requiring a pectoralis muscle flap in the future. Using another branch of the thoracoacromial artery for anastomosis can preserve the vascular pedicle to the pectoralis major muscle flap. We successfully preserved the pectoral branch and later used the pectoralis muscle in 1 patient. Second, when the patient has had a pectoralis major muscle flap elevated at a previous procedure, there may be distortion of the usual anatomy of the TAC system. Three of 10 patients in our study were in this category. In each situation, the TAC system could be dissected and used. In some respects, dissection was actually facilitated in this situation as the pectoral branch of the thoracoacromial artery was readily exposed due to its location on the previously elevated pectoralis muscle flap. This branch was then easily traced to the main trunk of the TAC system.

In conclusion, we report our experience using the TAC system for microvascular anastomoses in 11 patients requiring free flaps for head and neck reconstruction in the presence of a vessel-depleted neck. The TAC system provides a reliable source of undisturbed vessels when cervical vessels are unusable or absent. The substantial drawback of this technique is the potential loss of the major vascular pedicle to the pectoralis major muscle myocutaneous flap, thereby preventing its future use, if required. However, with selective dissection of other branches of the thoracoacromial artery, the pectoral branch can be preserved. If a pectoralis major muscle flap has been elevated during a previous procedure, it is still possible to use the TAC system provided that adequate time has passed for neovascularization to occur. Exposure of the TAC system is not technically complicated and should be included in the armamentarium of any surgeon performing complicated head and neck reconstructions.

Accepted for publication November 27, 2001.

This study was presented at the annual meeting of the American Head and Neck Society, Palm Desert, Calif, May 14, 2001.

Corresponding author and reprints: Jeffrey R. Harris, MD, Department of Surgery, 2D, University of Alberta, WC Mackenzie Centre, 8440 112 St, Edmonton, Alberta, Canada T6G 2B7 (e-mail: jharris@powersurfr.com).