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Radial Forearm Free Flap

last modified on: Wed, 01/17/2024 - 09:17

Return to: Microvascular Surgery Protocols

GENERAL CONSIDERATIONS

  1. Indications
    1. The forearm flap has been used for just about everything imaginable in the area of head and neck reconstruction. Currently, we prefer this flap for reconstruction of defects involving the tongue, intraoral soft tissue, oropharynx, soft palate, hypopharynx, cervical esophagus, and selected cutaneous defects. This flap is now also being used in the reconstruction of extended hemilaryngeal defects.
  2. Contraindications
    1. See Microvascular Surgery General Considerations. The major contraindications to the use of this flap are inadequate collateral blood flow to the hand via the ulnar artery, certain identifiable radial artery anomalies, and prior surgical or traumatic injury to the radial artery. The nondominant arm should be used if possible; however, functional deficit following flap harvest is minimal.
  3. Pertinent Anatomy
    1. The forearm flap is a fasciocutaneous flap based on the fasciocutaneous perforators from the radial artery. The number of perforators is greatest between 12 and 20 cm from the takeoff of the radial artery, and these are the vessels captured in the distally located skin paddle. Another smaller group of perforators is located within several centimeters of the radial artery takeoff. Several recognized anomalies of radial artery anatomy exist, and the surgeon performing this flap should be aware of these. The venous drainage of the flap occurs via a superficial system including the cephalic vein or a median contribution to this vein and a deep system including the venae comitantes. These systems frequently anastomose via a communicating vein between the venae comitantes and the median basilic vein in the cubital fossa. Harvest of a large superficial vein proximal to this communicating vein allows use of both venous drainage systems. A study by Lui, et al, 2008 however demonstrates that there is no significant advantage to using a dual (superficial and deep) venous drainage system, as it did not influence flap survival rates when compared to superficial venous drainage only. Innervation of the flap is possible through the medial or lateral antebrachial cutaneous nerves. If needed, the superficial branch of the radial nerve may also be used as a vascularized nerve graft. The flap may be harvested with a rim of radius bone, no more than one-third the diameter of the radius and no longer than approximately 10 to 11 cm. The blood supply to the bone is derived from fascioperiosteal branches of the radial artery and a musculoperiosteal plexus in the area of the flexor pollicis attachment. The bone stock available is much less than in other osseous free flaps.

PREOPERATIVE PREPARATION

  1. Evaluation
    1. Exclude previous traumatic or surgical trauma to the donor site through history and careful physical exam. Inspect the hand for evidence of potential arterial anomalies.
    2. Perform an Allen test to ensure adequate ulnar collateral blood flow. Refill of the entire hand within 6 seconds is evidence of patent collateral flow. The patient should avoid hyperextending the fingers (as it can cause a false positive). Pressure on the radial artery must exceed 11 pounds for the test to be accurate. Some cases will appear equivocal (apparently slow refill), or the color of the hand will not appear to change during the test. In these cases, systolic digital blood pressure measurement will allow objective documentation of the status of the ulnar collateral flow. We obtain this test on all of our patients.
    3. With a magic marker write: "No IV No Needles" on the intended flap arm. Instruct the patient and family not to allow anyone to draw blood or start an IV in the intended flap arm.
    4. Communicate with the anesthesia team regarding the planned procedure so that no IVs or arterial lines are placed in the intended flap arm.
  2. Potential Complications
    1. See Microvascular Surgery General Considerations. The most frequent complication of this flap is incomplete healing of the skin graft placed to cover the donor site. While this problem is not infrequent and patients should be aware of it, it is rarely a major problem. Other potential complications include stiffness or weakness of the hand, numbness in the distribution of the superficial branch of the radial nerve, and cold intolerance of the hand. All patients should be aware that the skin-grafted donor site will look very abnormal for approximately two to three months until the skin graft has completely healed and the color begins to more closely approximate the color of the surrounding skin.

NURSING CONSIDERATIONS

  1. Room Setup
    1. See Free Flap Room Setup
      1. Standard arm boards for operating table x 3
    2. The room should be warmed prior to the patient's entry to maintain normothermia during anesthesia induction and positioning.
  2. Instrumentation and Equipment
    1. Standard
      1. Major Instrument Tray 1, Otolaryngology
      2. Major Instrument Tray 2, Otolaryngology
      3. Bipolar Forceps Trays
      4. Microsurgery Instrument Tray, Otolaryngology
    2. Special
      1. Dermatome set-up
      2. Lead hand instrument
      3. Latex-free rubber bandage, 6 in
      4. Steri-Cuff extension hose, 6 in
      5. Steri-Cuff pneumatic tourniquet cuff, 18 in
      6. Sterile soft roll
  3. Medications (specific to nursing)
    1. Heparin sodium injection, 1,000 units per ml, 10 ml vial
    2. Papaverine injection, 60 mg per 2 ml, 2-ml ampule
    3. PhysioSol irrigation solution, 500 ml (be sure the PhysioSol is in the warmer in sufficient time to be warm when the surgeon requests it)
  4. Prep and Drape (click for photos: Prep and Drape Radial Forearm Free Flap)
    1. Standard prep, 10% providone iodine
    2. Drape
      1. Prepare the head and neck separately from the arm
      2. Prepare the operative arm to include the axilla and place towels to separate from head incision
      3. Head drape
      4. Towels around face, neck, and chest
      5. Impervious drape under the arm on a "hand table"
      6. Split sheet
  5. Drains and Dressings
    1. Suction drain under flap: 10 mm
    2. Bolster consists of adaptic and fluff gauze
    3. Web roll applied loosely to arm from below elbow to wrist
    4. Ace bandage, elastic, 4 in and/or 6 in (8 to 10 layers)
    5. Plaster splint, 5 x 35
    6. SoftRoll, 4 in and 6 in used under the tourniquet during the surgery
    7. Sterile foam over the skin graft
  6. Special Considerations
    1. Heparin sodium injection 5,000 units in sodium chloride 0.9% 500 ml in syringe, Luer tip 5 cc syringe with 24-gauge IV cannula is used to irrigate vessels.
    2. Papaverine 60 mg in 500 cc sodium chloride 0.9% in a Luer tip 10 cc syringe with 18-gauge IV cannula will be used topically to irrigate for vasospasm.
    3. Use all measures to keep body temperature at least 37.6° (warming blanket, room temperature).
    4. See Skin graft protocol.

ANESTHESIA CONSIDERATIONS

  1. General
    1. Positioning: Table will be turned 180°. Flap arm is placed on two arm boards or ironing board supports at 90° to body. A Mayfield headrest may be used.
    2. Peripherals: No IV or arterial lines in flap arm. The anesthesia tubing must not be placed along the body on the flap side.
    3. Prep: The entire arm and hand on donor side are prepped including the axilla in continuity with the chest. The head and neck are prepped as required for the extirpative procedure. Sterile tourniquet is placed on upper arm.
  2. Specific
    1. No IV, blood draw, blood pressure cuff or other monitoring devices on flap arm
    2. See General microvascular protocol

OPERATIVE PROCEDURE

  1. Inflate tourniquet up to diastolic pressure and mark out veins and intended skin paddle. Deflate tourniquet, elevate and exsanguinate the arm using an Esmarch wrap, reinflate tourniquet to 250 mm Hg.
  2. Elevate the flap from ulnar to radial side toward the flexor carpi radialis in the plane just above the muscular fascia. Take care to leave paratenons intact on tendons. Do not incise proximal margin of flap.
  3. Elevate flap from radial to ulnar side to the brachioradialis tendon. Take care to preserve the superficial branch of the radial nerve and to capture the cephalic vein. Ligate and divide the radial artery and venae comitantes distally, proximal to their contributions to the superficial palmar arch. Incise skin on proximal margin of flap only through dermis and elevate skin proximal to the flap in the subdermal plane. This allows harvesting of a proximal "paddle" of subcutaneous tissue and preservation of the branches of the medial or lateral antebrachial cutaneous nerves running into the skin paddle. The extent of subcutaneous tissue harvested will depend on the reconstructive needs.
  4. Incise the skin over the cephalic vein proximally to the cubital fossa. Identify the venous branching pattern and perforating vein. Identify the main branch of the lateral antebrachial cutaneous nerve.
  5. Elevate the skin and subcutaneous paddles proximally off of the flexor carpi radialis and brachioradialis. Be careful to preserve the more proximal fasciocutaneous perforators.
  6. At this point, the flap with the vascular pedicle is elevated from distal to proximal by elevating the radial artery and venae comitantes with the skin and subcutaneous paddles.
  7. The tourniquet is released and hemostasis in the wound obtained.
  8. Define the venous anatomy at the cubital fossa. In most cases, the median basilic vein and continuation of the median vein contribution to the cephalic vein can be harvested proximal to the perforating vein. This anatomy allows two large veins to be harvested that drain both the deep and superficial systems. Occasionally, one large vein will be identified.
  9. The flap may be replaced and the vascular pedicle divided when the recipient site is prepared.
  10. Closure is performed by harvesting a 0.018-inch skin graft to cover the donor defect. The radial skin edge should be advanced to cover the exposed radial nerve; advancement of the ulnar skin edge should be avoided because the ulnar artery may be injured. If the paratenon over the flexor carpi radialis tendon appears tenuous, the medial margins of the superficial flexor group and flexor pollicis may be sutured together over this tendon; in our experience, this is rarely required. The proximal arm is closed over a 10 mm fully perforated suction drain. The skin graft is sutured in place with 4-0 chromic suture, and a bolster of adaptic dressing material and sterile foam is applied. The arm is wrapped in sterile Webril, and a volar plaster splint that places the wrist in approximately 45° of extension is placed. The splint is secured with a sterile ace wrap. A second option is using the Wound Vac system for closure. After placement of the STSG, interface is placed on the STSG site. The Wound Vac foam is then placed over this. Using standard Wound Vac protocol the site is sealed such that it is airtight. The wound vac is then set up and left in place until POD # 5. A small splint is placed as well, primarily to keep the hand in appropriate position to maintain the seal.

POSTOPERATIVE CARE

  1. See Microvascular Surgery General Considerations.
  2. Keep arm elevated on two pillows. The arm drain remains in place for approximately two to three days. The splint and skin graft bolster are removed after seven days, or after five days if the Wound Vac system is used.

REFERENCES

Allen EV. Thrombangiitis obliterans: methods of diagnosis of chronic occlusive arterial lesions distal to the wrist with illustrative cases. Am J Med Sci. 1929;178:237-244.

Brown MT, Cheney ML, Gliklich RL, et al. Assessment of functional morbidity in the radial forearm free flap donor site. Arch Otolaryngol Head Neck Surg. 1996;122: 991-994.

Cormack GC, Duncan MJ, Lamberty BGH. The blood supply of the bone component of the compound osteocutaneous radial artery forearm flap-an anatomical study. Br J Plast Surg. 1986;39:173-175.

Fenton OM, Roberts JO. Improving the donor site of the radial forearm flap. Br J Plast Surg. 1985; 38:504-505.

Frodel JL, Funk GF, Capper DT, et al. Osseointegrated implants: a comparative study of bone thickness in 4 vascularized bone flaps. Plast Reconst Surg. 1993;92:449-455.

Funk GF, Valentino J, McCulloch TM, et al. Anomalies of forearm vascular anatomy encountered during elevation of the radial forearm flap. Head Neck. 1995;17:284-292.

Kamienski RW, Barnes RW. Critique of the Allen test for continuity of the palmar arch assessed by Doppler ultrasound. Surg Gynecol Obstet. 1976;142:861-864.

Timmons MJ. The vascular basis of the radial forearm flap. Plast Reconst Surg. 1986;77:80-92.

Urken ML, Weinberg H, Vickery C, Biller HF. The neurofasciocutaneous radial forearm flap in head and neck reconstruction: a preliminary report. Laryngoscope. 1990;100: 161-173.

Valentino J, Funk GF, Hoffman HT, McCulloch TM. The communicating vein and its use in the radial forearm free flap. Laryngoscope. 1996;106:648-651.

Liu Y, Jiang X, Huang J, Wu Y, Wang G, Jiang L, Li W, Zhao Y. Reliability of the superficial venous drainage of the radial forearm free flaps in oral and maxillofacial reconstruction. Microsurgery. 2008;28(4):243-7.