Osteocutaneous Radial Forearm Flap Free Tissue Transfer Treatment & Management

Discuss the rigors of extensive surgery and potential complications with each patient. The patient must be prepared to remain in the hospital for 7-10 days postoperation.

Once the donor arm is chosen, avoid all future venipunctures, arterial line, and blood pressure cuff placements. Shave the donor forearm and lay the arm on an arm board. Usually, position the arm 30-45° from the body until harvest. At this time, move the arm approximately 90° from the body so that 2 surgeons can operate on either side of it. Place an appropriately sized tourniquet on the upper arm and check the cuff's function. Use of a tourniquet is optional but helpful, especially during radius bone harvest. Because the patient is usually placed in a supine position, the volar aspect of the forearm remains pointing superiorly.

Then, sterilely prepare the arm and drape it in separate limb drapes while the arm is wrapped in a stockinette. Complete these steps before preparing the clean-contaminated head and neck region. Also, prepare and drape the upper thigh to allow split-thickness skin graft (STSG) harvest for coverage of the forearm donor site. Until the harvest is initiated, cover the leg and arm with sterile drapes to prevent cross-contamination from the head and neck. A separate operating room (OR) instrument table and scrub nurse should be available during harvest so that harvest can occur concurrently with the extirpative procedure to minimize anesthetic and operative time.

Anesthetize and monitor the patient as indicated for the long procedure. To allow for intraoperative nerve stimulation, avoidance of muscle relaxants is preferred. Administer IV antibiotics, systemic steroids, and histamine-2 receptor antagonists.

Osteocutaneous radial forearm free flap harvest

Sterilely uncover the surgical donor site of the arm and draw the skin paddle on the volar aspect of the forearm, as shown below. The size and shape of the paddle depend on the needs of the head and neck defect. The paddle is proximally biased about 2 cm proximal to the wrist crease. The paddle is also ulnarly biased but insufficient to disrupt the perforators in the lateral intermuscular septum to the skin. These 2 positional biases aid in cutaneous coverage of the internal fixation plate hardware of the donor radius described below.

Next, exsanguinate the arm with elastic dressing and elevate it while the tourniquet cuff is inflated to well above arterial pressure (ie, 270 mm Hg). Remove the elastic bandage.

Perform the medial longitudinal skin incision first. Make this incision (as all skin incisions) with a number 15 scalpel. Then, perform subfascial dissection medially to laterally using tenotomy scissors, as shown in the image below. Make the proximal and distal incisions after confirming the defect size in the head and neck recipient site. Take care proximally to avoid the medial antebrachial cutaneous nerve traveling in the muscular fascia. Distally, exercise caution lateral to the flexor carpi ulnaris tendon to avoid damage to a superficially running ulnar artery pedicle. As dissection proceeds laterally, subfascial dissection occurs over the palmaris longus tendon (if present) and the flexor carpi radialis tendon. Maintain the paratenon on these tendons to assist with STSG take during wound closure.

Make the radial longitudinal skin incision and perform lateral-to-medial subfascial dissection over the large brachioradialis (BR) tendon, shown below. Take care to preserve the dorsal radial nerve. The radial artery pedicle can run close to the BR tendon medial margin; use exceptional caution in separating the lateral intermuscular septum from the medial border of this tendon. Next, widely undermine the BR tendon and retract it laterally. Distally, dissect the radial artery pedicle and place a vessel loop around it. Because of the ulnar-biasing, the cephalic vein and lateral antebrachial nerve are not frequently included in the harvest but can be, depending on need. The fasciocutaneous paddle should now be pedicled by only the lateral intermuscular septum and the radial artery pedicle.

Proximally, make a linear or curvilinear incision from the skin paddle to the antecubital fossa. Then, perform subcutaneous dissection to elevate skin flaps medially and laterally. The medial antebrachial cutaneous nerve can then be followed to the antecubital fossa prior to harvest. Also, follow the radial artery pedicle to the antecubital fossa using microclips or bipolar cautery on small vascular branches between the pedicle and underlying musculature. Those branches lying deep to the skin paddle must be preserved because they feed the underlying radius periosteum. Typically, clean the pedicle and follow it proximally to the radial artery's takeoff from the brachial artery. The paired venae comitantes frequently coalesce into a single larger vein near the antecubital fossa. If a superficial vein is preserved from the fasciocutaneous paddle, it can be followed into the antecubital fossa. These veins frequently connect to the deeper venous network as well.

Next, release the flexor digitorum superficialis (FDS) from the distal medial radius and retract it medially to visualize the flexor pollicis longus (FPL). Using a scalpel, split the FPL and periosteum over the longitudinal midline of the volar radial surface (on the ulnar side of the lateral intermuscular septum). Determine this midline by means of palpation, remembering that the radius enlarges distally.

Next, accurately determine the required length of radius bone from the head and neck defect and measure along the exposed radius. Generally, harvest the vascularized bone graft between the pronator teres (PT) and BR tendon insertions, remembering that the distal osteotomy must be made at least 2.5 cm proximal to the radius styloid process to allow insertion of at least 2 bicortical screws during internal fixation. Proximally, the bone can be harvested beyond the PT insertion, but the PT tendon must be reinserted to the remaining radius bone and/or fixation plate. (Using this technique, as much as 12 cm of radius bone has been harvested.) Mark the proximal and distal osteotomies by sharply incising the periosteum in a beveled fashion, so that the resulting bony defect is beveled somewhat concavely.

Use a fine-blade oscillating saw to make the longitudinal radius cut, as in the image below. Irrigate copiously with antibiotic-containing saline irrigation. The longitudinal radius cut is placed to allow harvest of approximately 50% of the radius circumference. Usually, cutting is started proximally. Because of the curvature of the radius and increased radius circumference distally, the frequency of harvesting too much of the radial circumference proximally is minimized. Next, make the proximal and distal beveled osteotomies with the saw, as shown below. Avoid past-cutting because this can weaken the remaining radius bone. Incise the dorsal periosteum lateral to the intermuscular septum and under or lateral to the retracted BR tendon, completing the bone-graft harvest.

Release the tourniquet and allow the OCRFFF to perfuse on its pedicle until its transfer to the recipient site. Bleeders are managed with bipolar cautery or hemoclips. Confirm adequate perfusion of the entire flap. First, clamp the distal pedicle and again confirm hand perfusion before actual pedicle sacrifice. Use silk ties and/or medium hemoclips during pedicle sacrifice, both proximally and distally. Then, transfer the OCRFFF to the head and neck recipient site for inset and microvascular anastomoses. Up to 2 osteotomies have been performed subperiosteally in the radius graft without vascular compromise to the bone graft.

Prophylactic internal fixation of donor radius and wound closure

Prophylactic internal fixation can be performed most efficiently after reinflating the arm tourniquet. Expose the dorsal radius proximally and distally. Position an appropriately sized 3.5-mm low-contact dynamic compression plate (AO Synthes, Davos, Switzerland) over the radius and bend it to the contour of the bone, as depicted in the image below. Typically, 14- to 18-hole plates are required, depending on the length of the harvested radius graft. Distally, retract the radial wrist extensors (ie, abductor pollicis longus, extensor pollicis brevis, extensor carpi radialis longus, extensor carpi radialis brevis) laterally and place at least 2 standard bicortical screws.

Proximally, visualize the supinator (S). With long-bone harvests, elevate this muscle subperiosteally and place the plate beneath it. Take care to protect the posterior interosseous nerve, a branch of the deep radial nerve that pierces the S. Place at least 2 (usually 3) bicortical screws proximally. To avoid the creation of additional stress risers, do not place screws in the defect cavity. See the image below.

Using a dermatome, harvest an STSG (0.015-in thickness) from the prepared thigh. Then, mesh the STSG and bring it up to the donor arm. Dress the leg with Xeroform gauze (Sherwood Medical, St Louis, Mo) or an occlusive dressing.

Reinsert the PT tendon into the remaining radius or fixation plate as necessary. Using absorbable sutures, suture the FPL remnant over the radius defect and plate. The FDS can usually be brought over the flexor carpi radialis (FCR) tendon to the radial skin edge. This method provides a second muscular layer over the bony donor site and helps the STSG take on the FCR tendon. Then, cover the defect with a 1.0:1.5 meshed STSG. Cover the donor site with Xeroform gauze, cotton balls, and a gauze wrap. Finally, apply a rigid plaster ulnar-gutter splint and wrap with an elastic bandage.

Perfusion of the flap and the hand are closely monitored, as is the motor and sensory neural integrity of the hand and fingers.

Keep the donor arm elevated. Take down the arm splint 5-7 days postoperatively and dress the donor site with a fresh Xeroform gauze and cotton wrap dressing for protection during healing. Remove the arm sutures and/or staples approximately 10 days postoperatively. Encourage the patient to perform normal movements with the donor arm after splint removal.

Monitor the arm and leg wounds during routine postoperative follow-up as dictated by the head and neck problem. Encourage normal wrist activity; physical therapy is needed only if limited range of motion or decreased strength is encountered. Postoperative radiographs of the donor arm are needed only to investigate arm symptoms.

Microvascular free flaps always carry the risk of ischemia and flap loss. Early detection of vascular compromise and expeditious flap revision is important and can result in overall success rates greater than 95%. As with the fasciocutaneous radial forearm free flap (FCRFFF), the most common donor site complication is poor split-thickness skin graft (STSG) take over the flexor carpi radialis tendon. This problem usually responds readily to wet-to-dry dressings and rarely requires debridement or regrafting.

Complications from the harvest of the radius bone include donor radius fracture, decreased range of motion, and decreased strength. Werle et al report eliminating radius fractures by using keel-shaped osteotomies and prophylactic plating of the donor radius bone.^[8] Their results have been reproduced by other authors. Kim et al looked at donor and recipient site complications in 52 patients who underwent osteocutaneous radial forearm free flap (OCRFF) for oromandibular and maxillofacial reconstruction.^[2] In their series, only one fracture of the donor site occurred, which was subsequently repaired without sequelae. With careful closure of the forearm, paying attention to the muscle coverage of the plate, these authors had no incidences of plate exposure in the forearm.

In more than 100 consecutive cases, the authors experienced no cases of symptomatic radius fractures that required any intervention. Interestingly, one patient fell on an outstretched donor arm on postoperative day 7 and suffered a humerus fracture; the plated radius was uninjured.

The rate of major surgical complications at the donor site was comparable or better for the radius bone harvest compared with a harvest of the fibula and scapula osteocutaneous flaps (7% vs 16%). Only 1 patient (0.9%) required plate removal because of hardware loosening, and 2 patients required another surgical intervention at the donor site. None of the above complications resulted in any further sequelae.

Limitations of wrist range of motion and strength have not been significant. Mean grip and pinch strength were at least 84% of the unoperated, and usually dominant, arm. Wrist range of motion was at least 87% of the control side. Again, operated arms are usually the nondominant arm, which may have decreased values at baseline. Any minimal limitation has generally been overcome with physical therapy. One case of an attritional tear of the extensor pollicis longus tendon tear from the end of a fixation plate placed too ulnarly occurred. This patient required repair and plate removal without sequelae. No instances of infection or loosening of donor arm hardware have occurred.

Thigh STSG donor sites become intermittently infected and require local wound care and topical antibiotics. However, they usually heal without difficulties.

As was shown in the authors' recent review, when compared with other commonly used osteocutaneous free flaps in head and neck reconstruction, patients with osteocutaneous radial forearm free flap (OCRFFF) had significantly fewer problems with wound infections, breakdown, and postoperative fistulae at the primary site. Also, at the authors' institution, OCRFFF patients had a shorter postoperative rehabilitation time as demonstrated by the length of ICU and total hospital stay. A similar percentage of patients were rehabilitated with tissue-borne dental prostheses in the OCRFFF group to the percentage for other osteocutaneous free flap groups without any problems with mandibular or bone graft fractures. When the prophylactic internal fixation technique is performed, as described in the previous section, donor site morbidity of the OCRFFF procedure is similar to that seen in the fasciocutaneous free flap procedure.

In a review by Clark et al, nonplated donor radii were shown to have sustained an unacceptably high fracture rate (18% among males and 32% among females).^[9] In addition, patients with nonplated donor radii had been wearing immobilizing splints for 6-8 weeks, whereas patients with prophylactically plated donor radii had their casts removed on postoperative day 5 and had been encouraged to resume normal activity thereafter.

Reconstitution and remodeling, which are both evidence of bone healing, are observable radiographically by 5 months postoperatively, with bony remodeling seen as early as 3 months postoperatively.

The soft tissue characteristics of the fasciocutaneous paddle are nearly ideal for intraoral reconstruction and yield improved function compared with the pectoralis major myocutaneous flap. The available bone is adequate for small-to-medium segmental mandibular defects, with the primary disadvantage being its inability to support osseointegrated implants. As previously mentioned, because of insurance and cost restrictions, the percentage of the authors' patients who are able to afford this type of rehabilitation is low.

Even in the setting of heavily radiated tissues, such as when treating patients with advanced mandibular osteoradionecrosis, reconstruction using OCRFFF achieves excellent functional results.

The possible integration of osseointegrated implants into the osteocutaneous radial forearm free flap (OCRFFF) radius bone graft would make it an even more desirable flap. The OCRFFF can readily tolerate a tissue-borne prosthesis and help rehabilitate mastication to a certain extent.

Hatoko et al described the use of calcium phosphate cement to fill the radius bone defect after harvesting radial forearm osteocutaneous flap in 5 patients.^[10] The maximum size of harvested radius was 10x50 mm, and the maximum volume required was 3-4 mL. No plating was used, but postoperative fixation of the forearm continued for 14 days. Postoperative radiographs revealed a uniform high-density mass that filled the bone defect, with only a 5% volume reduction at 5 months, suggesting the need for overfilling the defect.

However, further studies of bone replacement that compare the use of calcium phosphate cement with internal fixation of the radius bone are necessary before adopting the technique because of the success and paucity of symptoms associated with the use of prophylactic internal fixation alone.

The authors' goal is to reintroduce this useful and versatile flap as a viable reconstructive option to the head and neck surgery community. Because of the orthopedic technology and principles that currently exist, the flap's stigmatization because of unacceptable donor site morbidity should be only historical. Future applications should become evident as the OCRFFF regains popularity.