Radial Forearm Tissue Transfer Treatment & Management

An informed consent is obtained.

A 2-team approach may be used. The arm is marked based on the estimated defect size. The cephalic vein is also marked because it usually decompresses with tourniquet inflation and may be difficult to visualize. The arm is exsanguinated with an elastic wrap, and the tourniquet is inflated to 250 mm Hg.

A number 15 blade is used to incise the periphery of the flap, extending in a curvilinear fashion into the proximal forearm. The subfascial plane is identified and elevated laterally to the FCR and medially to the BR. The pedicle is identified distally between these tendons and ligated. Further distal elevation reveals the superficial branch of the radial nerve, which lies on the lateral aspect of the BR. Medially, it courses to the undersurface of the muscle and should be preserved. The plane between the BR and FCR is then dissected carefully, with adequate retraction allowing for identification of the pedicle on the undersurface of the BR.

Tiny perforating vessels that provide blood supply to the radius are identified and cauterized or clipped; otherwise, they bleed when tourniquet pressure is released. If bone is harvested, the distal perforators are preserved and followed to the radius. The bone is cut obliquely (keel shaped) so as not to overcut and weaken the radius. Care is taken not to shear the vessels from the bone during harvest. The pedicle can be followed to the antecubital fossa.

The cephalic vein is identified proximally. The LABC is identified in proximity and harvested if required for neural anastomosis. Further dissection between the FCR and BR allows for complete elevation and skeletonization of the pedicle. The tourniquet is released, and the vessels are further cleaned of their adventitia under loupe visualization.

At an appropriate time, the pedicle is ligated proximally, and the flap is inset in the defect. The donor site defect is minimized with a purse-string suture of 3-0 Vicryl. The donor site is carefully closed with a split-thickness skin graft that covers any tendon denuded of paratenon with nearby muscle prior to skin grafting. A skin graft that has been pie crusted by hand rather than run through a mesher has a better cosmetic appearance.

Suitable recipient vessels in the neck should previously have been identified. The vessels are cleaned of adventitia under the binocular microscope. Using microvascular techniques, the anastomoses are then performed. The authors use a 9-0 nylon suture for the arterial anastomosis and either 9-0 nylon or a venous anastomotic device for the venous anastomosis or anastomoses. The vascular clamps are removed from the vessels, and flow is reestablished and verified. Papaverine is placed on the pedicle, and closure is completed. Suction drains are carefully placed in the neck and secured with sutures to avoid direct contact with the pedicle. If a Doppler is to be used for postoperative assessment, a suture is placed to mark the pedicle site.

The arm is dressed with Xeroform and a bolster and loosely wrapped with Kerlix. A plaster volar splint is fabricated and secured with an elastic bandage. A feeding tube is placed if necessary, and the patient is transferred to the recovery room. An intensive care bed may be necessary, depending on the experience of the nursing personnel.

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

The ideal technique by which a flap can be assessed is only theoretical and practically varies depending on the flap, the 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 needle prick, is the most reliable in trained hands. Devices that may assist nurses or residents in monitoring a flap include a standard Doppler placed over the pedicle or a laser Doppler.

Recently, use of the implantable Doppler has become more common. This Doppler can be implanted on the artery or the vein. It is very sensitive to a change in flow. Perhaps it's most useful in getting personal at the bedside to examine the flap. Arterial problems usually manifest within 24 hours; venous congestion often develops 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. An aspirin (325 mg) is administered rectally, orally, or per feeding tube starting on the first postoperative day; many administer the medication immediately after the patient leaves the operating room.

The splint on the arm is changed on the fifth postoperative day, and the skin graft is evaluated. A lightweight splint is fabricated by physical therapy, and the patient wears this until the skin graft site is healed completely. Active physiotherapy is instituted to ensure recovery of wrist and hand function.

Upon discharge from the hospital, the patient is continued on one aspirin each day unless contraindicated. The first postoperative visit generally occurs 1-2 weeks after release from the hospital. Flap and skin graft viability are assessed. Any remaining sutures are removed.

The donor and recipient sites are 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, and other specialists, as required. Patients generally resume an oral diet when the flap has been used in the oral cavity or pharynx approximately 2-3 weeks following discharge assuming no complications arise. Continuing dental/oral surgery evaluation and management, when appropriate, allows for placement of dentures or implants at an appropriate time.

The primary problem with the radial forearm free flap is the cosmetic outcome of the donor site. The surgical defect almost always requires skin grafting. Aggressive attempts at primary closure can result in compartment syndrome, a dreaded complication. Methods to decrease the defect size have been reported and may improve cosmetic outcome. Meticulous attention to closure is the most reliable technique for optimizing the cosmetic result the donor site. Tendon exposure with delayed wound healing has been reported in up to 40% of patients. Basing the flap more on the radial side and covering the tendons with proximal muscle has drastically reduced the frequency of this complication to less than 10% of cases.

Recent reports of the use of cadaveric dermis on the wound have been presented. This provides a better cosmetic result but may take up to 3 months to heal. Covering the dermis with a thin split-thickness skin graft or substituting a full-thickness skin graft have not been shown to increase cosmetic or functional outcome. Problems with the skin graft donor site are rare, but infection and delayed healing are possible.

Donor site infection or hematomas are possible but rare. The authors do not routinely place drains in the arm, although many surgeons rely on closed suction drains to evacuate any blood from the mid and proximal forearm. Compartment syndrome is a rare but serious problem. The arm should not be closed under significant tension in an effort to avoid a skin graft. Patients undergoing these flaps do not usually notice a subjective loss of range of motion or function in the arm. However, an objective decrease in absolute strength can often be measured. Radial forearm osteocutaneous flaps (see the image below) may result in fracture of the radius. Prophylactic intraoperative plating and postoperative casting are of benefit and have minimized this complication.

As with any microvascular surgery, free flap failure is a risk. 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 thrombosed vessel(s) are performed if required; occasionally, this necessitates vein grafting.

For flaps with venous congestion where patients cannot be returned to the operating room immediately, leeches may be used to temporarily relieve the congestion. This technique should rarely be used for long-term salvage. Leeches work by removing the engorged blood from the flap and thereafter allowing an artificial venous outflow through their bite in the patient's flap skin. Blood flow through the bite is enhanced by an enzyme, hirudin, found in the leech saliva. 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 when used, and patients should prophylactically receive an antibiotic that covers beta-lactamase resistant organisms if leech therapy is used. Blood loss can be significant, and the hemoglobin should be carefully monitored. Leeches are placed directly on the flap at intervals throughout the day. When they are sated, they fall off the flap and are discarded as medical waste.

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 (streptokinase and heparin), shown to improve flap survival, through the flap. Systemic heparin should generally be started in the operating room and continued in the postoperative period for 7 days. Hematomas may develop as a result of anticoagulation. Drains should be placed carefully in the operating room and not removed until the heparin has been discontinued.

The radial forearm flap is extremely reliable. The overall flap success rate of microvascular free tissue transfer in larger series is 90-98%. Nevertheless, all microvascular procedures are dependent on the experience of the surgeon and various patient factors. A take-back rate of 10% is expected, and about half of these flaps are successfully salvaged.

The reliability of the flap and the ability to reinnervate the flap via the lateral or medial antebrachial cutaneous nerves has been well established.^[3] The functional implications of such reinnervation have yet to be determined. Techniques for improving donor site morbidity are also being evaluated. Improving cosmesis through different grafting materials and suture techniques will ultimately make this flap even more appealing.