Radial forearm free flap - Fasciocutaneous

Considerations

• • Anatomy 

    • Tissue harvested 

      • Skin - Keep in mind: The volar forearm is hair bearing

      • Fascia

      • +/- bone

      • +/- sensory innervation - lateral antebrachial cutaneous nerve

    • Pedicle

      • Radial artery and its perforators 

        • Branch of the brachial artery

      • Venae comitantes x 2 +/- cephalic vein

      • Length: up to 20 cm 

      • Caliber: 2-2.5 mm  

    • Forearm anatomy

      • YouTube (8:08) - The nerves in the forearm and the hand - Excellent cadaver dissection showing both musculature and nerves

    • YouTube (16:08) - Forearm Muscles Part 1 - Anterior (Flexor) Compartment - Anatomy Tutorial

      • Musculature

      • Brachioradialis

      • Flexor carpi radialis

      • Palmaris longus

      • Nerves

      • Superficial branch of radial nerve

      • Lateral antebrachial cutaneous nerve

  • Indications by defect 

    • Oral cavity

    • Oropharynx

    • Hypopharynx 

    • Skin +/- low volume soft tissue +/- bone of face 

    • Skull base

  • Advantages 

    • Thin and pliable

    • Effective for contouring concavities and convexities  

    • Includes skin paddle

      • May include muscle, tendon, bone, and sensory nerve 

    • Tolerant of radiation therapy 

    • Allows two team approach 

      • One team for the flap harvest and one for the cancer extirpation 

  • Laterality 

    • If possible, choose the hand opposite the patient's preferred handedness

• Allen's test

  • • Examines radial and ulnar artery flow and continuity into the palmar arch system 

      • Relax the hand and fingers, avoid finger hyperextension 

      • Occlude both the radial and ulnar arteries, then release 

      • Refill of the entire hand within 6 seconds is evidence of patent collateral flow; See 1991: The Allen's test: analysis of four methods

• • Be wary of radial sided vascular insufficiency

    • • In the case of radial artery discontinuity, the radial forearm flap may still be harvested if the radial defect is reconstructed using reverse saphenous vein or cephalic vein grafting

  • Flap design

• • • Size

      • The size is determined based on the defect

      • Dr. M often starts by marking 9 x 12 cm flap and tailors down the flap as needed 

    • Beavertail 

    • 2009: Beavertail modification of the radial forearm free flap in base of tongue reconstruction: technique and functional outcomes

    • Bilobed

      • 1994: A new bilobed design for the sensate radial forearm flap to preserve tongue mobility following significant glossectomy 

    • 2004: Functional outcomes after hemiglossectomy and reconstruction with a bilobed radial forearm free flap

    • 2010: Double bilobed radial forearm free flap for anterior tongue and floor-of-mouth reconstruction

    • Folded

    • 1995: Folded free radial forearm flap for reconstruction of full-thickness defects of the cheek

    • 2001: Soft-Tissue reconstruction of the face using the folded/multiple skin island radial forearm free flap

    • 2013: Modified folding radial forearm flap in soft palate and tonsillar fossa reconstruction

• • Secondary defect 

• • • Primary closure of the forearm defect is possible

      • 2004: Primary closure of radial forearm flap donor defects with a bilobed flap based on the fasciocutaneous perforator of the ulnar artery 

    • Often, STSG from the ipsilateral thigh is required 

Preparation

• Order and post sign: No IV / blood draw from the donor arm

  • Most importantly, communicate to the patient and family re this point both before and on the day of surgery

  • Communicate with the Anesthesia team re this point

• Special equipment

  • Esmarch bandage

  • Webril padding 

  • Tourniquet

  • Dermatome

  • Casting materials vs splint

  • Microvascular tray  

• Positioning

  • Place the donor arm on the operating board in 90 degree abduction at the shoulder

• Marking

  • Mark the course of the radial artery

  • Mark the course of the cephalic vein

  • After determining the defect, design the flap on the forearm

    • Generally, center the flap over the radial artery

    • Consider the hair-bearing skin 

  • Mark a lazy S incision extending from the antebrachial fossa to the proximal apex of the flap

    • Optional: Form a notch near the antebrachial fossa 

Procedure

• Place the Webril and tourniquet just proximal to the antebrachial fossa

• Exsanguinate the arm with the elastic (Esmarch) bandage

• Inflate the tourniquet to 250 mm Hg

• Incise the periphery of the flap, beginning on the medial (ulnar) aspect of the flap and extending in a curvilinear fashion into the proximal forearm with the number 15 blade

• Carry the dissection down medially to the flexor carpi radialis (FCR) in a subfascial dissection to expose the intermuscular septum

• Follow the FCR into the proximal arm

• Identify the pedicle proximally and dissect it free

• Incise the lateral (radial) aspect of the skin down through the skin and subcutaneous tissue to the brachioradialis muscle (BR)

• Dissect on the BR in the subfascial plane, with the superficial branch of the radial nerve, which lies on the lateral aspect of the BR muscle, identified and preserved

  • Stay on the muscle

• Dissect the intermuscular septum containing the pedicle off of the BR

  • If there is no concern for ulnar artery viability, the distal pedicle can be divided at this point

• Identified the cephalic vein proximally and either harvest it with the flap or leave it intact

• Identify the lateral antebrachial cutaneous nerve (LABC) in proximity and harvest it if required for neural anastomosis

• Identify and divide (cauterize or clip) tiny perforating vessels that provide the blood supply to the radius

  • Otherwise, they will bleed when tourniquet pressure is released

  • If bone harvest is planned, these 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. It is safe to take 40% of the diameter of the radius. Care is taken not to shear the vessels from the bone during harvest

• Dissect the skin paddle and the pedicle free from all surrounding subcutaneous tissue

• Identify the pedicle as one artery and one vein if possible

  • If it is not possible to identify the venous pedicle to one vessel, two venous anastomoses can be done or, if the venae comitantes are of adequate caliber, venous drainage can be based on only one branch

• Release the tourniquet 

• Obtain hemostasis in the donor wound 

• The vessels may be further cleaned of their adventitia under loupe visualization

• At an appropriate time, ligate the pedicle proximally, and insert the flap in the defect

  • If bone was harvested, an orthopedic surgeon may plate the remaining radius

• The donor site defect may be minimized using a purse-string suture of 3-0 Vicryl - or - by approximating the corners with deep buried 3-0 Vicryl

• Carefully close the donor site with a split-thickness skin graft (or acellular dermis) harvested from the ipsilateral thigh

  • See Split thickness skin graft (STSG) page

  • Cover 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

• Dress the arm with Mepitel One Safetac silicone dresing followed by the sponge (use multiple if needed) inside a prep kit wrapped in xeroform placed on top of the skin graft. On top of this will be the wound vac sponge that should be stapled all around to help apply pressure to the graft site. 

  • Loosely wrap with Kerlix

  • Cover with Webril. Take care to thoroughly pad the bony prominence of the wrist. 

• Splint the arm with an A-line cast 

  • Keep the hand in safe position, think "beer can" position 

  • Wrap with ACE bandage

Sample operative report

The patient was already on the OR table. The resection was previously completed and will be noted separately. A safety check was previously performed.

The *** forearm and *** lateral thigh were prepared in standard sterile fashion at the beginning of the case. The Webril was placed around the upper arm followed by the sterile tourniquet and it was connected to the tourniquet. The arm was then exsanguinated with the Esmarch bandage. 

The skin paddle was designed at the distal aspect of the forearm, centered on the radial artery. Its dimensions were *** cm by *** cm, shaped as a ***.

The incision was made first on the ulnar aspect through the skin down to the level of the paratenon and then over the paratenon from the ulnar aspect. The radial portion of the incision was made through skin down to the level of the muscle fascia. The flap was rolled onto the brachioradialis tendon to include the cephalic vein in its lateral (radial) aspect. The flap was elevated over the brachioradialis. The radial artery and venae comitantes were clamped, divided, and ligated with #3-0 silk ties. The flap was elevated from distal to proximal direction; Perforating vessels were clamped, divided, and ligated with #3-0 silk ties or ligated with hemoclips and divided. 

The incision was made through the skin from the antecubital fossa to the proximal portion of the flap. The soft tissue was elevated off the soft tissue of the flap so that the cephalic vein would be included in the flap itself. The soft tissue was divided on both sides of the vein down to the level of the musculature and then reflected medially. The brachioradialis tendon was elevated away from the underlying vessels, and this was traced superiorly. Again, any perforating vessels were clamped, divided, and ligated with #3-0 silk ties or ligated with hemoclips and divided. The communicating branch from the deep system to the antecubital vein was identified and preserved. The venae comitantes were then divided superior to the connection to the communicating vein, such that the communicating vein remained intact and drained into the antecubital vein.

The radial artery was identified and dissected until it exited from the brachial artery. The tourniquet was then let down. The total tourniquet time was *** minutes. The flap was seen to be bleeding well at this point in time. Any bleeding was controlled with bipolar cautery or ligation with #3-0 silk ties or hemoclips. After *** minutes, the flap was then disconnected from the arm. The antecubital vein and radial artery were clamped, divided, and ligated. The vessels were irrigated with heparinized saline until the effluent through the vein ran clear.

The forearm defect was irrigated was saline and Bacitracin irrigant. The proximal portion of the incision was closed in two layers using buried interrupted #3-0 Polysorb in the deep layer and running subcuticular #5-0 Biosyn to approximate the skin. 

A split-thickness skin graft was harvested from the *** lateral thigh with a deduct of 16/1000 inch. The lateral thigh was dressed with *** Benzoin and Tegaderm.

The STSG was placed into the forearm defect in the arm and inset with simple #5-0 Fast absorbing gut.  Once the peripheral edges were sutured into place on the arm, small "pie crust" incisions were completed on the STSG over the muscle aspect, while leaving STSG over the paratenon intact. Quilting stitches were placed into the underlying muscles. *** Xeroform was then made into little rolls and placed between the tendons followed by a big bolster dressing. The arm was then placed into a splint in a safe position and wrapped with *** Kerlix followed by an ACE wrap. *** Doppler refill on the thumb was less than 2 seconds at the end of release of the tourniquet.

Meanwhile the flap was brought into the head and neck. It was inserted into place into the defect using #3-0 Polysorb in a vertical mattress fashion. 

The vessels were then brought down into the neck. The *** vein and the *** artery were selected as the recipient vessels. The adventitial tissue was cleaned on the donor and recipient vessels. The recipient artery was approximated to the radial artery and then anastomosed using simple interrupted #9-0 Nylon on the MV100 needle. *** The recipient vein was approximated to the antecubital vein and sutured in a running fashion using #9-0 Nylon on the MV100 needle. The vessels were released. Excellent flow to the flap was visualized. The flap was pink and bleeding well on skin scratch.

*** drains were placed into the neck. The *** drain was loosely sutured to keep it off the vessels and flap. These were secured to the skin using #3-0 Nylon. 

The neck was irrigated with a copious amount of saline. No further bleeding was encountered. No evidence of a chyle leak was seen.

The flaps were then replaced. The *** lip was repaired with 3-0 Polysorb deeply and on the lip mucosa, 5-0 Chromic on the vermillion and 5-0 Surgipro on the skin. The platysma and the subcutaneous tissue layers were closed using #3-0 Polysorb and the skin was closed using #5-0 Surgipro. 

The NG tube was placed through the nasal cavity into the stomach. It was then sutured to the membranous nasal septum using a #3-0 Nylon. The patient's mouth was then suctioned. The endotracheal tube was then removed and a *** #6 LPC Shiley tracheostomy tube was inserted and sutured to the skin at four points using *** #3-0 Nylon. 

The patient was cleaned and transferred to the Intensive Care Unit in satisfactory condition. No complications were encountered. Final needle and sponge counts were correct.

Post-op

• • See Free flap - Admission protocol page

  • Forearm donor site care

  • Examine the neurovascular integrity of the fingers 

  • Elevate the arm on two pillows 

  • Remove arm drain once output is appropriate, usually POD 3

  • Remove cast POD 5

    • If skin graft present, leave Mepitel in place; Replace Xeroform, Telfa, Kerlix wrap

  • Activity: NWB x 5 days, partial weight bearing x 5 days

• Complications 

  • Donor site 

    • Hand ischemia 

    • Radial nerve injury

    • Hypoesthesia over dorsum of hand

    • Hematoma

    • Graft loss 

  • Recipient site 

    • Fistula 

    • Stricture

    • Flap loss 

Pearls & Pitfalls

• • Pearls

    • Identify the pedicle between medial head of the brachioradialis and the flexor carpi radialis

    • Dissect the radial artery to its origin, but divide it distal to the radial recurrent artery

  • Pitfalls

  • Avoid injuring the dorsal branch of the radial nerve, which exits into the distal forearm from underneath the brachioradialis muscle

Links

• YouTube (5:30) - Radial forearm harvest (AHNS)

  • YouTube (7:39) - Radial Forearm Flap by Microsurgery Made Easy - Instructional cadaver dissection 

• YouTube (14:22) - Radial Forearm Flap HD

• Microsurgeon.org - The Radial Forearm Flap

• eMedicine - Radial Forearm Tissue Transfer

• Iowa Head and Neck Protocols - Radial Forearm Free Flap

• UTMB - Microvascular Free Flaps Used in Head and Neck Reconstruction