Microsurgical Anastomosis of the Scapula Bone

37 Microsurgical Anastomosis of the Scapula Bone

Rainer Schmelzeisen and Friedrich W. Neukam

Introduction

The scapula region offers the unique possibility of allowing the harvest of one or two soft-tissue flaps in combination with a vascularized bone graft (Sieverberg, Banis, and Acland, 1985; Swartz et al., 1986). Different aspects of the flap can be mobilized independently from each other, yet vascularized via one pedicle. Since the medial aspect of the scapula is rather thin and often has to be placed at the upper border of the mandible, the bone graft is frequently not suitable for insertion of dental implants (Schultes, Gaggl, and Karcher, 2002). The skin of the scapula offers a good color match with that of the head and neck area, and has the added advantage of being thin and pliable (Smith et al., 2007).

Anatomical Considerations

The vascular supply of the scapula region is derived from the subscapular artery, which divides into thoracodorsal and circumflex scapular artery 1–2cm below the axillary artery. The circumflex scapular artery passes through the triangular space bordered by the teres major and minor muscles and by the long head of the triceps muscle. The artery supplies the infraspinatus muscle and the lateral border of the scapula at the proximal aspect of the bone. The inferior third of the lateral border of the scapula is vascularized by the angular branch of the thoracodorsal artery (Fig. 37.1).

After it has passed through the muscular triangle, the circumflex scapular artery divides into a descending cutaneous branch (the parascapular flap), and a transverse cutaneous branch (the scapula flap) (Fig. 37.2).

Harvesting

For harvesting a combined osteocutaneous flap, the parascapular orientation of the soft-tissue pedicle offers a safe vascular supply.

For harvesting the bone, the teres major muscle must be cut at the scapula tip. However, some muscular attachment has to be left on the bone to avoid interference with the periosteal blood supply. In general, it is sufficient to harvest 2–2.5cm from the lateral border to match the height of the mandible. The inferior third of the scapula is nourished by the angular branch of the thoracodorsal artery. This autonomous vascularization does not allow an osteotomy, if it is necessary to bend the bone graft (Fig. 37.3). The disadvantage of the soft-tissue pedicles of the scapula region, in common with most free flaps, is that there is no sensory supply.

Indications

The scapula region offers unique opportunities for reconstruction of skin, bone, subcutaneous tissue, and, especially, combinations of bone and soft tissues. Among all flaps derived from the head and neck area, the texture and color of the skin at the scapula region almost perfectly match the texture and color of the facial skin. Although the skin is relatively thick, it is not as bulky as that of myocutaneous grafts, or free flaps from the iliac crest. In general, scapula grafts should always be considered for complex soft-tissue defects, or combined bone and soft-tissue defects, as long as neither massive volume augmentation nor large bone volume are required (Fairbanks and Hallock, 2002).

Isolated de-epithelized scapula soft-tissue grafts may also be used and are ideal for tissue augmentation, for example, in patients with hemifacial microsomia.

Combined osteocutaneous flaps are suitable for reconstruction of the posterior aspect of the mandible and the ascending ramus, when implant insertion is not a requirement. The soft-tissue pedicle may be used for reconstruction of the floor of the mouth or for extraoral lining. As the scapular and parascapular skin and the bone can be mobilized independently from each other, the flaps are ideal for reconstruction of combined oral and extraoral defects (Coleman et al., 2000). Only rarely will there be a need to harvest bone grafts alone.

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