Rectus Abdominis Tissue Transfer Treatment & Management

No specific preoperative vascular evaluation is required for patients who are to undergo rectus free tissue transfer. Appropriate informed consent is obtained by both the extirpative and reconstructive surgeons.

The flap can be harvested simultaneously by 2 teams. The defect size is measured or estimated, and a flap that is slightly larger than the defect is designed. Landmarks are palpated, which include the ribcage, pubis, and anterior superior iliac spine. The dissection does not extend beyond these landmarks. A unilateral flap that includes a periumbilical portion is created. This ensures capture of these perforators.

Depending on tissue requirements, the skin paddle can be designed vertically, totally overlying the rectus muscle, or obliquely, along an axis between the umbilicus and the tip of the scapula with much of the skin paddle lateral to the linea semilunaris. ^[8] This latter orientation is possible because of an axial blood flow pattern from the portion of skin overlying the muscle in the periumbilical area parallel along this axis. When designed in this manner, the lateral aspect of the flap is much thinner than the portion overlying the muscle and can be useful when the defect requires soft tissue of varying thickness.

The skin is incised, and cautery is used to dissect through the fat. Use caution when working with the rectus muscle because musculocutaneous perforators may be violated. Some surgeons prefer to place tacking sutures from the skin to the anterior sheath to preserve the viability of the perforators. The anterior rectus sheath is identified. The sheath is transected superiorly and inferiorly beneath the skin incision. The inferior incision is placed above the arcuate line in order to facilitate closure without the use of mesh. Laterally, the linea semilunaris is used as a landmark for the lateral sheath incision.

Preservation of as much sheath as possible is important to facilitate primary closure. The medial fascial incision is made in proximity to the linea alba, again taking care to preserve perforating vessels with dissection. A subfascial plane is then elevated superficially to the rectus muscle superior and inferior to the skin paddle. This allows wide exposure of the entire rectus muscle. Laterally, the muscle is elevated beginning superiorly to allow posterior dissection, leaving the posterior sheath intact. With continued inferior dissection, the vascular pedicle is identified along the lateral aspect of the muscle. Cautery is used to transect the muscle superiorly. Inferiorly, the pedicle is retracted for protection as the muscle is cut. With the flap attached only by the pedicle, the surrounding fascia is cleaned and the pedicle dissected until the external iliac vessels are reached.

When the flap is ready for transfer, the vessels are clamped and the pedicle is divided. The abdomen is closed in a primary fashion. Proper and careful closure of the anterior sheath is important to prevent a hernia (see the image below). Some surgeons routinely reinforce the closure with mesh; this is particularly important if the sheath has been violated inferior to the arcuate line. A suction drain is placed in the wound.

The rectus sheath is closed to prevent postoperative hernias. The defect is almost always closed primarily.

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The flap is inset in the defect site, and the pedicle is oriented to avoid tension or kinking. Suitable recipient vessels are identified and cleaned of adventitia. The anastomosis is performed under magnification in a routine fashion. At the completion of the anastomosis, venous clamps are released and retrograde flow through the anastomosis is observed. The artery is then released; papaverine may be placed on the vessels. The configuration of the pedicle is optimized, suction drains are placed, and wound closure is completed.

Patients are monitored closely in the hospital. The skin paddle is monitored frequently for signs of vascular compromise.

The ideal technique by which a flap can be assessed is only theoretical and can vary in practicality depending on the flap, patient, available equipment, and other factors. Based on individual preference, cost, and familiarity with monitoring techniques, various monitors are available. The criterion standard, direct visualization and assessment of capillary refill with or without a needle prick, is the most reliable in trained hands. Devices that may assist nurses or residents in monitoring a flap include a standard or laser Doppler device placed over the pedicle. Arterial problems usually manifest within 24 hours; venous congestion often manifests 48-72 hours postoperatively. Frequent evaluation and careful monitoring allow for early identification of problems.

Fluid balance and overall patient condition are also monitored. The authors use prophylactic antibiotics and steroids for 24 hours; many routinely use prophylactic antibiotics much longer. Aspirin (325 mg) is given rectally, orally, or per feeding tube starting on the first postoperative day; many administer the medication immediately after the patient leaves the operating room.

An oral diet is started (if the patient did not have a gastric tube) when bowel sounds are present. Postoperative ileus is common for a short time following surgery and generally resolves spontaneously. Ambulation is helpful for hastening the resolution of ileus, heralded by the return of bowel sounds.

A pillow is placed on the abdomen to assist with coughing. Stool softeners are also useful to minimize abdominal strain. We use an abdominal binder for 4 weeks.

Upon discharge from the hospital, the patient continues to take 1 aspirin each day unless contraindicated. The first postoperative visit generally occurs 1-2 weeks after release from the hospital. Flap viability is assessed. Any remaining sutures are removed. The recipient site is evaluated for complications. Removal of the feeding tube and/or tracheotomy tube, if still present, is considered. The patient is also evaluated by a speech pathologist, physical therapist, or other specialists, as required.

A study by Kagaya et al indicated that in patients who undergo reconstruction with a free rectus abdominis myocutaneous flap for total or subtotal maxillectomy, factors independently associated with flap volume loss include weight reduction, young age, and postoperative radiotherapy. The investigators also reported that fat volume remained stable in the study patients over time, while muscle volume was reduced to less than 40%, if influencing factors were absent. In addition, the report found that “the fat volume tended to gather toward the central-cranial direction, while the muscle volume gathered toward the cranial direction,” with the total flap volume gathering toward the central direction. ^[5]

Donor site complications are uncommon but possible. Hernias may occur when the rectus sheath has not been properly closed or is insufficient for adequate closure. Wound infections may also occur. A general surgeon may be of assistance in wound closure in patients at risk.

As with any microvascular surgery, free flap failure is a risk. A study by Kubo et al indicated that in free flap microsurgical head and neck reconstruction, disruption of the anastomosed blood vessels common after anastomosed site infection. The study, which included rectus abdominis, anterolateral thigh, radial forearm, jejunum, and latissimus dorsi flaps, found that vein disruption (without accompanying artery disruption) occurred in five out of 11 cases; artery and vein disruption, in two cases; and artery disruption (without accompanying vein disruption), in one case. ^[9]

Flap salvage following venous or arterial thrombosis is possible if early identification of vascular compromise leads to early (urgent) operative intervention. If thrombosis is identified and appropriately managed or pedicle geometry is optimized if twisting had occurred, the flap may be saved. Thrombectomy and revision of any thrombosed vessels are performed if required; occasionally, this necessitates vein grafting.

For flaps with venous congestion in patients who cannot be returned to the operating room immediately, leeches may be used to temporarily relieve the congestion. This technique should be used only very rarely for long-term salvage. Leeches work by removing the engorged blood from the flap and, thereafter, allowing artificial venous outflow through their bite in the patient's skin (ie, flap). An enzyme, hirudin, found in the leech saliva, enhances blood flow through the bite. This enzyme is a powerful anticoagulant and, together with removal of the tiny clot that forms at the bite site, allows flaps to slowly bleed for hours. Leeches can transmit Aeromonas hydrophila, a gram-negative rod, and patients should receive antibiotic prophylaxis that covers beta-lactamase–resistant organisms if leech therapy is used.

If one or all of the veins are thrombosed, the arterial anastomosis may be allowed to remain intact at the discretion of the surgeon. Venous drainage occurs through the unattached veins. The authors irrigate University of Washington solution (ie, streptokinase and heparin), which has been shown to improve flap survival, through the flap. Generally, systemic heparin should be started in the operating room and continued in the postoperative period for 7 days. Hematomas may occur as a result of anticoagulation. Drains should be placed carefully in the operating room and not removed until the heparin has been discontinued.

Survival of the flap is dependent on the immediate identification and treatment of complications. A flap survival rate of greater than 90-95% is expected in experienced hands. Flap complications occur in 0-20% of patients.

Patient prognosis and survival is more dependent on the primary tumor and oncologic treatment thereof than on the technique chosen for reconstruction. Postoperative radiotherapy is frequently administered when healing is complete.

Innervation of both sensory and motor supply to the flap is still being evaluated. It has yet to be proven efficacious with regard to improving speech or swallowing. It adds little to the surgery to reanastomose the nerves; thus, the drawbacks are few. Functional rehabilitation following total glossectomy or significant resection of the base of the tongue is vexing. Any advantage achieved by innervating the flap is worthwhile. ^{[10, 11]}

The routine use of mesh to reinforce the abdominal closure is also controversial. Certainly, the presence of a postoperative hernia is undesirable. Consultation with a general surgeon may be of value in achieving primary closure.