The chest wall defects can be divided into the simple skin and soft tissue defects, the defects in chest wall support structure such as ribs and sternum, and the full-thickness chest wall defect according to the extents of the defects. The classification according to the extents of the defects may provide guidance for the repair of the chest wall layer by layer.

The chest wall defects can be divided into sternal defect, anterior chest wall defect, lateral chest wall defect, and posterior chest wall defect according to the positions of the defects. The classification according to the positions of the defects can offer help in selection of skin flaps for repair. It is noteworthy that the transverse rectus abdominis myocutaneous (TRAM) flap often can’t reach the upper end of the chest wall, and the forced application will result in distal flap necrosis.

The partition of chest wall defect generally refers to the partition of anterior chest wall. For selection of therapeutic regimen, the anterior chest wall can be divided into eight regions. The upper boundary of the anterior chest wall is the clavicle, the lower boundary is the margin of the hypochondrium, the lateral sides are bilateral axillary lines, and the anterior chest wall is divided into three parts such as left, middle, and right parts through the midclavicular lines; then through the horizontal line at the lower boundary of the third rib and the xiphoid process level, the chest wall is divided into three parts, such as upper, middle, and lower parts, so that the chest wall is divided into eight regions (Fig. 16.2).

The wounds after resection of tumor in the resection can be repaired with local skin flap; the design of the skin flap is to contain blood vessels as far as possible, such as lateral chest wall flap and intercostal flap; and when the random pattern skin flap is used, attention should be paid to the length-to-width ratio of the skin flap.

The latissimus dorsi muscle is a flat and triangular muscle with its flat and wide aponeurosis starting from the lower six thoracic vertebras, all lumbar vertebras, sacral vertebras, supraspinous ligament, and posterior iliac crest. The muscle fibers are divided into two parts, such as the upper horizontal part and the inferior oblique part, and aggregate toward the upper outer side and end at the spine of the lesser tubercle of the humerus. The latissimus dorsi myocutaneous flap has a blood supply from multiple sources, including the thoracodorsal artery, intercostal artery, and lumbar artery as well as their accompanying veins, of which the thoracodorsal vessels are the main nutrient vessels. The thoracodorsal artery is the terminal branch of the subscapular artery. The subscapular artery is given off from the third section of the axillary artery and passes through the armpit to run downward, subsequently gives off the circumflex scapular artery, and, finally, becomes the thoracodorsal artery. The thoracodorsal artery and vein run under the myolemma at the inner surface of the latissimus dorsi muscle; after entering into the muscle, they are divided into the lateral branch and the medial branch; the lateral branch runs downward at 2–3 cm behind the anterior margin of the muscle bell, and the medial branch is parallel to upper margin of the muscle and run inward. The motor nerve of the latissimus dorsi muscle is the thoracodorsal nerve, which accompanies with the blood vessels to enter into the muscle.

The latissimus dorsi myocutaneous flap pedicled with the thoracodorsal artery, and its rotational arc can reach up to the head and neck, shoulder, upper limb, and ipsilateral chest. It has a wide range of clinical applications, is one of skin flaps with most extensive range and most versatile functions in the body which are available for free transplantation or pedicled transplantation, and is commonly used for repair of a large area of skin and tissue defects and the defects which are associated with muscle defects and require carrying out functional reconstruction and the breast reconstruction.

An oblique line which is parallel to the anterior margin of the latissimus dorsi muscle is drawn at 2 cm behind the anterior margin of the latissimus dorsi muscle, and it is the body surface projection of the thoracodorsal vessels. The myocutaneous flap is designed along the body surface projection line. The transplanting method and harvesting range for latissimus dorsi myocutaneous flap are determined according to the wound status in the donor site. The more commonly used design methods include the latissimus dorsi myocutaneous flap which takes the skin on the waist and back as the main donor site and the transverse latissimus dorsi myocutaneous flap which takes the upper half back of the transverse skin as the main donor site. When the surgery is performed, the patient takes the lateral position or hemilateral position, the skin tissue is incised for the armpit along the anterior margin of the latissimus dorsi muscle, the anterior margin of the latissimus dorsi muscle is exposed, the clearance behind the muscle is bluntly dissected, and the thoracodorsal artery, vein, and nerve can be exposed. The blunt dissection is continuously performed toward the distal end, the travel path of the neurovascular bundle in muscle is determined, the end point of the muscle is cut off, the desired width and length are harvested, and the latissimus dorsi myocutaneous flap is formed to repair the wound. The donor site is directly sutured or treated with skin transplantation.

According to the need of the repair, the rectus abdominis myocutaneous flap can be designed as longitudinal rectus abdominis myocutaneous flap and transverse rectus abdominis myocutaneous flap. For repair of the chest wall defects, the longitudinal rectus abdominis myocutaneous flap is more commonly used, and it is required to confirm that the internal thoracic vessels are not damaged before surgery; otherwise it is needed to selectively use other skin flaps for repair. The lower abdominal TRAM flap is mostly used for breast reconstruction.

The rectus abdominis muscle is located on both sides of the abdominal midline and is separated by the abdominal white line. It starts from the pubic symphysis and pubic bone, travels upward, and ends at the front of the sternum xiphoid periosteum and the fifth to seventh costal cartilages. The whole length of rectus abdominis muscle is divided into several muscle bellies by three to four transverse tendinous intersections; the tendinous intersections are closely integrated with the anterior sheath of the rectus abdominis muscle. The blood supply of the rectus abdominis myocutaneous flap is mainly from the superior and inferior epigastric arteries; the superior epigastric artery is a direct continuation of the internal thoracic artery, and it passes through the sternocostal triangle downward to reach the rectus abdominis muscle, penetrates into the muscle from behind the rectus abdominis muscle, and is anastomosed with the branch of the inferior epigastric artery near the navel; the inferior epigastric artery is given off from the medial wall of the external iliac artery below the inguinal ligament, at the junction of the inner two fifth and the outer three fifth of the inguinal ligament, and it runs obliquely toward the upper inner side behind the transversalis fascia, after crossing the lateral margin of the rectus abdominis muscle; it goes up to enter into the rectus abdominis muscle from behind the muscle and forms into the terminal branch near the area beside the navel. In the process of running within the muscle, both the superior and inferior epigastric arteries give off myocutaneous perforators to feed the skin tissue on the surface and are anastomosed respectively with the branches of lateral perforators of the posterior intercostal arteries, the anterior cutaneous branches of lumbar arteries, superficial epigastric artery, and superficial iliac circumflex artery. The rectus abdominis muscle is subject to control of the lower six pairs of intercostal nerves.

When the longitudinal rectus abdominis myocutaneous flap is designed, the myocutaneous flap ranges up to the xiphoid process and down to the site above the pubic symphysis. The medial side is the abdominal midline, and the lateral side can exceed the lateral margin of rectus abdominis muscle. The skin tissue, fascia, and the anterior layer of anterior sheath of the rectus abdominis muscle are incised layer by layer. When the superior epigastric artery is taken as the pedicle, the rectus abdominis muscle is transversely cut off at the distal end of the myocutaneous flap, and the inferior epigastric artery and vein are ligated and severed; the dissection is performed at the deep surface of the rectus abdominis muscle to the pedicle of the xiphoid myocutaneous flap, and the pedicle of skin should have enough length to facilitate rotation. The navel is retained in situ. The incised anterior sheath of the rectus abdominis muscle is sutured, and the abdominal donor site is closed and sutured (Fig. 16.7). If the required tissue volume is large, the TRAM flap in the lower abdomen can be used.

The pectoralis major is fan shaped with a large range, and the starting point is divided into three parts such as clavicular part, sternocostal part, and abdominal rib part. The clavicular part starts from the medial half of the clavicle, and the muscle fibers travel obliquely toward the lower outer side; the sternocostal part starts from the front of upper six costal cartilages on the lateral side of the sternum, and in general, the muscle fibers travel parallelly and outwardly; the abdominal rib part starts from the anterior sheath of rectus abdominis muscle and the distal ends of fifth to seventh ribs, and the muscle fibers travel obliquely toward the upper outer side. Three parts of muscle fibers aggregate outwardly to form a flattened tendon to the end of the crest of the greater tubercle of the humerus. The blood supply of the pectoralis major muscle comes from multisource; there are three main sources: the thoracoacromial artery, the pectoral branch of the axillary artery, and the perforating branches of the internal thoracic artery. The pectoralis major muscle is mainly controlled by the lateral pectoral nerve and the medial pectoral nerve.

There are mainly two methods of chest defects repairment with pectoralis major muscle: The first method is to take the perforating branch of the internal thoracic artery as the pedicle to form the myocutaneous flap, and then the myocutaneous flap is turned over reversely to repair the wound. The second method is to take the thoracoacromial artery as the pedicle to form the myocutaneous flap to repair the wound.

The marking method for the body surface projection of thoracoacromial artery approach is shown in Fig. 16.11, ab is the connecting line between the shoulder peak to the xiphoid process, the point o is the point of intersection between the line cd made from the clavicle midpoint and the connecting line ab, both lines are vertical, and the cob line is the body surface travel path of thoracoacromial artery.

The myocutaneous flap is designed along the body surface line according to the need of repairing the defects, the range of the design reaches upward to the level of armpit crimple and downward to the level of the xiphoid process, the inner boundary reaches the sternal margin, and the outer boundary reaches the anterior axillary line. When the surgery is performed, the pedicle skin is incised firstly, and then the skin and the full-thickness pectoralis major muscle are incised along the outer margin of the skin flap, and the myocutaneous flap is separated at the deep surface of fascia propria. After the pectoralis major muscle is lifted up, the blunt dissection is performed at the deep surface of the pectoralis major muscle to the pedicle, and after the neurovascular bundle locating at the deep surface of pectoralis major muscle is found, the skin at the medial margin of the skin flap is incised along the design line and the full-thickness pectoralis major muscle; the pectoralis major myocutaneous flap is formed and transferred to repair the wound.