< The Scapula Bone Flap

MICROSURGEON.ORG

atlas of microsurgery techniques and principles
Scapula Bone or Osteocutaneous Flap

The Scapula Bone Flap

Anatomic considerations

Tissue:
Not typically taken alone, the lateral and inferior aspect of the scapula can be harvested in combination with the scapular, parascapular, dorsal thoracic, latissimus, TAP or serratus flaps. Alternatively the bone can be combined with multiple soft tissue flaps based on a combination of territories being fed by the subscapular artery to form a complex chimeric flap.
Blood Supply:
There are two alternate blood supplies to harvest scapula bone:
A. Angular scapula branch from the thoracodorsal artery (most common origin). This branch can arise from the serratus artery (common) or the subscapular (more rare). The long leash of this pedicle allows for more mobility of the bone flap.
B. Bone branches from the circumflex scapular system to the mid-lateral scapula. These have a short leash.
Variations:
Two bone flaps can be harvested for a so-called bipedicle bone flap (see Coleman and Sultan, Plast Recon Surg 87:685, 1991) that is used in combination with a soft tissue flap off the subscapular axis.
Pedicle length:
Pedicle anatomy is dependent upon the flap the scapula bone is combined with. Since it arises from the subscapular vascular pedicle, the leash the flap is harvested on can be quite long.

The scapula bone flap is usually taken in combination with another soft tissue flap from the subscapular artery tree, to form a chimeric flap. As defined by Hallock (Plast Recon Surg 117:151e, 2006), a chimeric flap "consists of multiple otherwise independent flaps that each have an independent vascular supply, with all pedicles linked to a common source vessel".

Vascular Anatomy

The lateral aspect of the scapula, inferior to the glenoid fossa, is supplied by a vascular pedicle originating from the subscapular arterial system. From 1 to 2 centimeters wide and up to 10 centimeters long, although thin, the bone can have applications when small vascularized bone grafts are indicated.

The angular branch artery from the thoracodorsal system (or less commonly serratus) supplies inflow to the inferior lateral scapula and the angle. Again the flap size is limited to a maximum width of 2 centimeters.

Scapula Bone Flap

The arterial branches to the lateral scapula originate on the circumflex scapular artery or the subscapular artery and sprout to the lateral edge of the scapula.

The arterial branches to the lateral scapula originate on the subscapular artery

Scapula Bone Flap

An angular branch can take origin from the latissimus artery, serratus branch or the subscapular artery.

Operative Procedure

The patient is prepped in the lateral decubitus position or the prone position. Marking for the soft tissue chimeric flap are made and the incision must keep in mind access to the scapula.

During harvest of the subscapular axis soft tissue flap, the surgical dissection is incorporated to the superficial lateral or inferior scapula and the overlying infraspinatus and teres minor muscles. The arterial branches to the lateral scapula (flap B below) are dissected to the subscapular artery axis or the branches to the angle of the scapula (flap A below) are used for a more inferiorly base bone flap. The line of osteotomy required for the scapula is exposed through the muscle and periosteum. The osteotomy is performed with a small oscillating saw.

Scapula Bone Flap

The lateral scapula bone segment is harvested with a soft tissue flap(s) based on the subscapular axis. Flap A is harvested via the angular branch artery and flap B from the lateral scapula branches off the circumflex scapular artery.

The scapula bone flap can be harvested with any one of the following flaps (or combination of these) to form a chimeric flap: