Radial Forearm Free Flap
- Distal skin paddle of the forearm commonly used in head and neck surgery
- It is an extremely versatile flap allowing intricate folding of the skin, using two or more skin paddles/ islands, and incorporating vascularised tendon and/or bone (osteocutaneous flap)
Quick Facts | |
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Tissue | Skin + Fascia (optional bone + tendon) |
Artery | Radial Artery |
Vein | Venae comitantes of radial artery (small). Cephalic vein (optional but commonly used) |
Pedicle length | Can be taken off at the bifurcation of brachial artery |
Decision MakingEdit
IndicationsEdit
Common reconstructive applications include:
- Floor of mouth, tongue, soft and hard palate, buccal mucosa, pharynx and oesophagus
- Lips
- Orbit
- External skin defects
- Incorporating part of radius as osteocutaneous flap for premaxillary, maxillary, nasal, and selected mandibular defects
- Incorporating palmaris longus tendon sling to support lower lip reconstruction
AdvantagesEdit
- Very pliable, thin skin, especially at distal forearm (one of thinnest skin flaps)
- Usually very little soft tissue bulk
- Large flap may be harvested (30 x 15cm)
- Multiple skin islands can be used
- Sensory innervation possible
- Can incorporate radius bone or tendon
- Easy flap elevation
- Large, reliable, constant vessels
- Long pedicle usually available
- Distant location of donor site from head and neck resection permits simultaneous harvesting and resection
- Large distal size of vessel allows it to be used as a "flow-through-flap" for an additional flap to be attached distally
DisadvantagesEdit
- Potentially poor skin quality: in certain individuals the flap may be quite bulky, especially proximally; this can compromise certain reconstructions
- Donor site morbidity: loss of skin graft and tendon exposure; visible donor site and possible poor cosmetic result
- Vascular: atherosclerosis (seldomly); postoperative vascular compromise of hand (rarely)
Surgical AnatomyEdit
Venous SystemEdit
- Main superficial veins of the forearm (cephalic and basilic veins) lie deep to the fatty layer of the forearm (small venous tributaries may be found in subcutaneous tissue)
- Cephalic vein - most commonly used single vein for venous drainage of RFFFs
- Large + thick- walled
- Relatively constant location deep beneath the subcutaneous fat
- Drains the anterolateral forearm
- Pathway:
- Formed by the confluence of superficial veins on the dorsal aspect of the hand
- Vein then traverses the "snuffbox" area to lie over the lateral side of the distal forearm
- Then courses more medially towards the mid-lateral cubital fossa
- Associated structures:
- Accompanied by the lateral antebrachial nerve
- The superficial branch of the radial nerve lies in close proximity to the vein in the distal third of the lateral forearm and over the "snuffbox” area up to the lateral aspect of the dorsum of the hand
- Be aware that it is often used for IV access - may cause fibrosis and/or thrombosis of the vessel
- Basilic vein
- Runs on medial aspect of forearm
- Median (antebrachial) vein of the forearm
- Lies between cephalic and basilic veins
- Usually thin walled and more superficial in subcutaneous fat layer when compared to cephalic
- Occasionally it may be large and be a better drainage system to use for a flap
- Large variety of venous interconnections may be encountered in the cubital fossa
- The median cubital vein - runs obliquely from lateral to medial to connect the cephalic and basilic systems
- Usually there is a connection between the superficial veins and the deep brachial venous system in the cubital fossa (this is usually between the brachial venae comitantes and the median cubital vein or the cephalic vein)
- The forearm and cubital fossa are invested by the deep fascia
- In the cubital fossa it is strengthened by the bicipital aponeurosis
- The perforating vein connecting the superficial and deep venous systems lies lateral to the bicipital aponeurosis and the brachial vessels immediately deep to it
NervesEdit
- Superficial nerves accompany the superficial veins
- Superficial branch of the radial nerve - close to cephalic vein in "snuffbox" region
- The lateral antebrachial nerve - termination of musculocutaneous nerve (found between the flexor carpi radialis and palmaris longus tendons)
- Palmar cutaneous branch of the median nerve - arises just above the flexor retinaculum becoming cutaneous between tendons of palmaris longus and flexor carpi radialis
- Elevation of a very distal skin flap may injure this branch and cause sensory loss of the proximal mid-palm
MusclesEdit
- Radial artery runs in the lateral inter-muscular septum which separates the flexor and extensor compartments of the forearm
- Medially are the flexor carpi radialis (FCR) and the other forearm flexor muscles
- Laterally is the extensor compartment
- Important muscular relations to radial artery:
- Proximal third of forearm:
- Superficial to supinator, pronator teres and flexor digitorum superficialis (FDS)
- Distal third of forearm:
- Superficial to flexor pollicis longus (FPL) and pronator quadratus
- At the wrist the radial artery lies between the brachioradialis and flexi carpi radialis tendons
- Proximal third of forearm:
- Brachioradialis
- Key muscle when elevating this flap
- The muscle overlies the anterolateral side of the artery
- It is supplied by the radial nerve of the extensor compartment, even though it is an elbow flexor
- Bulky muscle belly lies anterior to, and covers, the radial artery in the proximal half of the forearm
- In the distal forearm the muscle becomes a flat tendon (tendon commonly covers the artery either partially or completely)
- Palmaris longus
- Tendon can be sacrificed without causing a functional deficit
- It is absent in around 13% of individuals
- Its tendon and muscle can be incorporated in a forearm flap for various reconstructive possibilities and it may therefore be an extremely valuable adjunct in complex reconstructions
Radial ArteryEdit
- The brachial artery bifurcates into ulnar and radial arteries
- Pathway of radial artery:
- Radial artery starts in the medial cubital fossa (1cm distal to the elbow crease, just medial to the biceps tendon)
- Then courses down the forearm in the lateral intermuscular septum (which separates the flexor and extensor compartments of the forearm)
- The radial artery courses down the forearm between the flexor carpi radialis and the brachioradialis (in lateral intermuscular septum)
- Terminated in the deep palmar arch
- Branches in the forearm:
- Radial recurrent artery close to its origin and distally
- Palmar carpal branch
- Superficial palmar branch
- Dorsal carpal branch (continuation of artery)
- Also giver off numerous muscular branches
- Septocutaneous perforators:
- Branches that supply the overlying fascia and skin
- Variable number (~12) - more in distal ⅓ of forearm
- Major perforator is usually found ≤2cm of the radial styloid process
- Periosteal blood supply to the distal radius is via branches to the deep flexor pollicis longus and pronator quadratus muscles; perforators also pass through the lateral intermuscular septum from the radial artery to the periosteum
Radius BoneEdit
- The distal 10 - 12cm of the anterolateral radius can be harvested as an osteocutaneous radial forearm free flap
- The shaft of the radius increases in size from proximal to distal and bows laterally
- The medial side of the shaft has a sharp interosseous border at the attachment of the interosseous membrane
- The wide distal end tapers into the pyramidal styloid process
Pre-operative PlanningEdit
- Harvesting the radial artery is associated with a remote possibility of vascular compromise causing claudication of the hand
- Confirm the presence of a radial arterial pulse
- Enquire about the patient’s occupation or leisure activities e.g. a pianist may be concerned about claudication
- Reynaud's disease is a pertinent medical condition
- Choice of arm depends on:
- Patient preference (usually contralateral to dominant hand)
- Previous IV lines, surgery, injury, scars, fractures or vascular compromise
- Ideally contralateral side to the resection to create enough space for 2 surgical teams
Assessment of palmar vascular archesEdit
Modified Allen Test
ConsentEdit
RisksEdit
Pain, infection, bleeding, bruising, swelling, scar (normal/hypertrophic/keloid), poor cosmetic result, delayed wound healing, failed free flap, failed skin graft to donor site, temporary or permanent sensory loss to hand (radial thenar region, metacarpal region of the dorsum of thumb or less commonly, of the dorsal hand), temporary or permanent stiffness/reduced function to hand, claudication
AlternativesEdit
Primary closure, local flap, alternative free-flap
Surgical InstrumentsEdit
- Tourniquet
- Shaver (if hair removal is needed)
- Arm table
Patient PositioningEdit
- Resection + elevation of flap can be done simultaneously as a 2-team approach to minimise the length of surgery
- Keep anaesthetic and other equipment at the foot of the bed to create more space
- Two bipolar and monopolar electrocautery systems are required
- Place the arm on an arm table
- Avoid hyperextending or hyperabducting the shoulder
- Shave the forearm
- Apply a tourniquet to the upper arm
- Adjust the operating table and/or the chairs so that the reconstructive surgeon and assistant are seated
Skin MarkingEdit
Surgical StepsEdit
- A tourniquet is placed on the upper arm and inflated to a pressure of 1.5x patient’s systolic pressure (usually 250 mmHg)
- The tourniquet should not be applied for more than 60 min
Subfascial flap elevationEdit
Vein selectionEdit
- The cephalic vein may be divided at any point along its course
- The cephalic vein may be dissected into the cubital fossa where connections may exist between one (or both) branches of the venae comitantes of the radial artery and, more commonly to the median cubital or the cephalic veins
- More rarely the deep and superfi- cial systems are anastomosed separately, utilising the cephalic and one of the large cubital veins
- Occasionally a very large dominant median vein of the forearm can be used
- Some avoid using venae comitantes for anastomoses, due to their small size
Flap disconnection and donor site closureEdit
- Deflate the tourniquet
- While awaiting reperfusion of the flap vasculature, the surgeon prepares the recipient vessels in the neck
- Control bleeding side-branches on the pedicle and on the flap with bipolar coagulation and/or clips before disconnecting the flap from its blood supply
- Attempt to advance skin to cover exposed tendons
- If primary closure is not possible (usually the case) a skin graft is required
- Skin grafts:
- Maintain epitenon over tendons
- Bury tendons by oversewing with deeper muscles
- Fix and immobilise skin grafts with sutures and dressing
- Volar splints should be applied to restrict movement of flexor tendons beneath skin graft
- Common sites for skin grafts:
- Inner upper arm
- Outer upper arm
- Thigh
- V-Y skin graft
Post-operative careEdit
- Graft is covered by a compression packing for at least 10 days
- Volar splint for 2 weeks
Follow-upEdit
ComplicationsEdit
- Long-term morbidity is often considered relatively minor and of secondary importance to oncology patients
- However, prolonged wound healing is inconvenient and may occasionally lead to significant morbidity
- Loss of skin graft
- Not uncommon to lose <25% of skin graft + for late wound breakdown to occur - both generally not considered graft failure and can be managed conservatively
- True graft failure can range from 10-20%
- "Biomechanical morbidity"
- Functional compromise and reduction in grip strength (10-20% weaker)[1]