Rectus Abdominis Muscle Flap
Originally described as a pedicled flap by Drever in 1977 and then as a free flap by Holmstrom in 1979, the rectus abdominis muscle flap is a common workhorse flap familiar to most plastic surgeons, with a reliable pedicle and simple dissection. A vertical, transverse, or oblique skin paddle can be harvested, but, for upper extremity coverage, this is commonly harvested as a muscle-only flap and covered with a split-thickness skin graft. Of the two pedicles, the deep inferior epigastric artery (DIEA) and its two venae comitantes are the most commonly dissected pedicle. The fascia can also be harvested to provide a gliding surface for tendons.
Upper extremity defects distal to the range for a pedicled latissimus flap, especially forearm and/or hand, such as extensive degloving or large defects where local flaps are inadequate ( Fig. 41.1 ).
Requiring soft-tissue coverage of exposed hardware or bony, tendinous, vascular, or neurologic structures due to trauma, oncologic resection, or wide débridement for necrotizing infections, chronic wounds, or ulcers.
Local flap options are limited due to prior radiation therapy damage.
Immediate flap coverage is appropriate for most oncologic defects but for other scenarios, confirmation of adequate debridement is critical prior to delayed flap coverage. In polytrauma patients, flap coverage should be delayed until the patient is hemodynamically stable.
There are no age restrictions.
Caution must be taken in patients with prior abdominal surgeries where the vascular pedicle or muscle itself may have been previously damaged, which may render the dissection difficult or the flap unusable.
There is a prior ventral hernia repair with mesh.
Patients with large ventral hernias or severe diastasis may have severely attenuated or damaged rectus muscles.
For athletes or very active patients for whom loss of abdominal strength may be detrimental to function, a muscle-sparing rectus or deep inferior epigastric perforator (DIEP) flap should be considered as an alternative.
The patient has a stoma that violates the rectus muscle.
The patient is pregnant.
Prior undermining for abdominoplasty or liposuction disrupts cutaneous perforators, and a myocutaneous flap should be avoided.
Prior thoracic radiation, coronary artery bypass graft (CABG) with harvesting of mammary vessels, and subcostal incisions may have compromised the superior epigastric pedicle.
An obese patient with a large pannus may have too much bulk for a skin flap.
Patients with excessive intraabdominal volume may be more likely to develop postoperative abdominal bulge/hernia and di? culty with closure if a large skin flap is harvested.
Free-tissue transfer is performed with caution in patients with hypercoagulable disorders.
Perform a physical examination for the presence of abdominal scars, hernias, or severe rectus diastasis, which may indicate compromised flap integrity.
Perform an Allen test to evaluate for radial versus ulnar artery dominance and hand perfusion.
Computed tomographic (CT) angiography may be useful preoperatively in patients with prior abdominal surgery, which may have compromised the vascular pedicle or muscle, and serves to identify perforators when a skin paddle is harvested or a DIEP flap is considered. Generally no imaging is needed for a muscle-only flap.
Consider angiography or CT angiography in posttraumatic defects to evaluate target vessels in the upper extremity that could be injured.
The paired muscles insert on the anterior fifth–seventh costal cartilages and the pubic symphysis.
The rectus sheath encompasses the muscle and is firmly adherent and therefore must be carefully dissected free along the tendinous intersections.
A relative area of weakness below the arcuate line should be recognized during closure.
Mathes-Nahai type II flap, the superior epigastric artery arises o? the internal mammary artery and joins the DIEA, which arises from the external iliac artery, entering the posterior rectus muscle infero-laterally ( Fig. 41.2 ).
The pedicle length is 7 cm (range 5–8 cm), and the artery is ~ 2–5 mm in diameter. The medial vein is commonly larger and can be traced to a point of convergence with the other venae comitantes.
The muscle is 6 cm (range 3–8 cm) wide, 1.5 cm thick, and 25 cm (range 23–30 cm) long. Up to 20–30% of the volume is lost due to denervation ( Fig. 41.3 ).
Rectus space hematoma or seroma may require needle aspiration or surgical drainage.
Abdominal bulge or hernia is uncommon and may require secondary correction.
Wound infection or dehiscence is especially likely in obese patients or patients with diabetes.
Flap thrombosis requires urgent surgical attention for salvage but is uncommon.
The muscle-only flap is thin and not easily debulked. The subcutaneous tissue in a myocutaneous flap can be too thick and require secondary lipocontouring.
The flap is insensate and nonfunctional.