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
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
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
Bilobed
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
2013: Modified folding radial forearm flap in soft palate and tonsillar fossa reconstruction
Secondary defect
Primary closure of the forearm defect is possible
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