Lower Limb Flaps

Arteries in the lower leg► Common Femoral Artery

Medial circumflex femoral artery Lateral circumflex femoral artery

(+ ascending and descending branches0

► Profunda Femoris Perforating brs of PF Descending genicular artery

► Popliteal Artery Ascending branch Genicular arteries (4)

► Anterior Tibial Artery Anterior tibial recurrent artery Medial malleolar arteries

► Dorsalis Pedis Artery and Arcuate Artery Deep plantar branch of DP Dorsal metatarsal and digital

arteries Medial and lateral tarsal arteries

► Peroneal Artery Perforating branch of peroneal

artery Lateral malleolar artery

► Posterior Tibial Artery Medial plantar artery Lateral plantar artery Plantar arch, plantar metatarsal

and digital arteries

Femoral artery

Anteromedial thigh flap► Femoral artery lies in subsartorial canal for its lower 2/3, and in this

portion gives off muscular and fasciocutaneous branches Perforators pass around both borders of sartorius to form a plexus at the level

of the deep fascia with an axis along the border of sartorius Range in size from 0.5-1mm Ø 80% cases the largest perforator passes around the superomedial border of

sartorius in the apex of the femoral triangle►Additionally also supplies muscle, so it’s diameter is 0.5-1.2mm►Accompanied by a vein►Supplies an area of 7x12cm on anteromedial thigh, with upper part of ellipse

overlying the apex of the femoral triangle► Area is supplied by the medial anterior cutaneous nerve of the thigh

Crosses medially in front of artery at the apex of the femoral triangle Can be raised as an innervated flap

► Type B fasciocutaneous flap Raised by identifying perforator first, the adjusting the flap position to be

centred over the artery

Saphenous flap► Saphenous artery is one of three terminal branches of descending genicular branch of femoral

artery Given off from medial side of femoral artery immediately before if enters the adductor hiatus Runs under sartorius and sends cutaneous branches anterior and posterior to muscle Runs under insertion of tendon to emerge posteriorly and continue in lower leg, usually only for about

12cm► 1.5-2mmØ, paired vc’s + GSV► Safe dimensions are 6x20cm, allowing primary closure of defect► Raised proximal to distal to visualise vessels and their relationship to tendon first► Can raise distally based flap, useful in stump wound breakdown

Lateral circumflex femoral artery

Tensor Fascia Latae►Origin – ASIS + iliac crest►Insertion – Lateral condyle of tibia via fascia lata►Innervation – Superior gluteal nerve (L4,5)►Action – Abducts, medially rotates and flexes thigh.

Hip stabiliser and assists in keeping knee extended ►Type I muscle

Branch off ascending branch of lateral circumflex femoral artery

Single artery 2-3mm diameter, paired venae comitantes Enters muscle on deep surface 9cm below ASIS

Rectus femoris► Type II bipennate muscle supplied primarily by LCFA► Origin: AIIS and deep/reflected part from superior acetabular rim► Insertion: Tibial tuberosity via superior part of patella, separated from femur by

suprapatellar bursa. Deepest layer of quadriceps tendon► Innervation: Br of Femoral nerve (L3,4), deep group, usually double

Upper branch gives a proprioceptive branch to hip (Hiltons law)► Action: Extend knee, stabilise hip joint and assists iliopsoas flex hip► Reliable vascular pedicle and considerable length (7x40cm)

Pedicle generally arises 5cm below top of symphysis pubis and runs downwards for 5-8cm before piercing the muscle on posteromedial border at junction of proximal and middle thirds

Divides into superior and inferior branches ► Rotation point is 7cm below inguinal ligament► Muscle is necessary for fully functional knee extension, so is not expendable except in spinal

patients (when gracilis or TFL can be used)► Skin paddle is based over lower 2/3 of muscle► Skin paddle sensation is supplied by intermediate anterior cutaneous nerve of thigh

Vastus lateralis► Type II muscle with dominant proximal pedicle from LCFA augmented by multiple

perforators from the posterior compartment► Origin: Greater trochanter, lateral lip of linea aspera of femur► Insertion: Tibial tuberosity via patella. Middle layer of quadriceps tendon► Innervation: Br of femoral nerve (L2,3,4), deep group► Action: Extends knee► Descending br LCFA runs down behind anterior edge of VL with nerve supply and

terminates in muscle in 90%, skin in 10%► As branches enter the muscle, multiple neurovascular hila are formed. One into

proximal third, three in proximal and middle third 60% cases, branches pierce deep fascia over anterior part of muscle and supply skin 40% cases septocutaneous perforators given off in intermuscular septum to reach deep

fascia (see ALT flap)► Main use is in repair of trochanteric pressure sores and salvage of hip wound

Can be raised as a free flap► Raised as from an incision slightly lateral to a line from ASIS to superolateral

aspect of patella

Anterolateral thigh flap► Type B fasciocutaneous flap► Supplied by descending branch of lateral circumflex femoral artery, usually

associated with 2 vc’s Length 8 – 16cm, diameter 2-3mm

► Pedicle transverses obliquely in groove between rectus femoris and vastus lateralis along with nerve to vastus lateralis

► Cutaneous perforators usually found in inferolateral quadrant of 3cm circle with centre at midpoint ASIS to superolateral corner of patella Can be septocutaneous or musculocutaneous perforators Can be raised as super thin, fasciocutaneous or musculocutaneous flap

► Maximum dimensions 12x8cm, with most distal part of flap at least 4cm above proximal end of patella

► Can incorporate anterior branch of lateral cutaneous nerve of thigh to create sensory flap

Profunda femoris artery

Gracilis► Origin – inferior pubic ramus, just below fascia lata► Insertion – subcutaneous surface of tibia, just behind sartorius► Innervation – obturator nerve

Single nerve with multiple fascicles to different portions of muscle (so useful in facial reanimation)

► Action – adduct thigh, flexes leg, assists medial rotation► Type II muscle

Adductor branch of profunda femoris or descending branch of MCFA Main pedicle 1-2mm diameter, paired vc’s One or to minor pedicles from superficial femoral artery enter muscle distally Pedicle courses from medial to lateral, and enters the deep surface about

10cm inferior to pubic tubercle (junction of upper 1/3 and lower 2/3) – pivot point

► Usually used as muscle only flap, but can be used as musculocutaneous flap with skin island over superior half of muscle

Hamstring flaps► Hamstring musculocutaneous flaps

were developed for treatment of ischial pressure sores, but can be transposed to anterior thigh

► VY musculocutaneous unit advancements have the advantage of being able to be re-elevated and advanced should pressure sores recur

► Can be raised on all 4 hamstring components or only biceps or semitendinosis

► Can be constructed to maintain innervation via posterior cutaneous nerve of thigh

► Large skin islands up to 12x35cm extending past the muscle borders can be raised

►Biceps femoris Origin: Long head from ischial

tuberosity, short head from linea aspera of lateral supracondylar line of femur

Insertion: Lateral side of head of fibula. Tendon is split by fibular collateral ligament of knee

Innervation: Long head is tibial division of sciatic nerve (L5-S2), short head is common peroneal branch of sciatic nerve (L5-S2)

Action: Flex leg and rotate laterally, extends thigh

Arterial supply: Type II. Major branches from the first profunda perforator at upper third junction. Branches from second perforator to lower part of long head and to short head. No anastomoses between short and long head. Further minor supply from inferior gluteal artery, MCFA, sup lat genicular artery

►Semitendinosis Origin: Ischial tuberosity Insertion: Medial surface of

superior part of tibia, just below gracilis

Innervation: Tibial part of sciatic nerve (L5-S2)

Action: Extend thigh, flex leg and rotate medially, extend trunk when thigh and leg are flexed

Arterial supply: Type II. Primary dominant pedicle from first profunda perforator and smaller pedicle superior to this from MCFA. Also small branches from inferior gluteal to origin, and inferior medial genicular to insertion

Lateral thigh flaps► Lateral thigh flaps are based on the perforators from profunda femoris, each of which

terminates by dividing into two branches at the point of the insertion of the lateral intermuscular septum into the femur (deep to origin of short head of biceps femoris)

► One of these branches pierces lateral intermuscular septum to supply vastus lateralis, the other runs on posterior aspect of intermuscular septum towards the iliotibial tract

► Consistent large perforator from 1st profunda perforator within 3cm of lower border of gluteus maximus (may be through the muscle), often the largest of the perforators Can raise skin flaps of up to 8x25cm, usually pedicled (superior lateral thigh flap) due to the

relationship to gluteus insertion► Also branch from 3rd profunda perforator (ED 1-1.5mm) at midpoint between greater

trochanter and lateral femoral condyle (middle thigh flap) Usually raised as a free flap due to long pedicle length Raised without deep fascia, so small area but thin and can be innervated As most perforators run anteriorly, best to plan this flap with only 1/3 – ¼ behind lateral

intermuscular septum► Venous drainage is by paired vc’s of the cutaneous perforators that tend to join as they

approach the femur► Nerve supply of the area is the lateral femoral cutaneous nerve

Emerges from beneath lateral end of inguinal ligament and divides into 2 branches that run down the iliotibial tract

Popliteal artery

Gastrocnemius

►Origin Medial head – Popliteal surface of femur, superior

to medial condyle Lateral head – Lateral aspect of lateral condyle of

femur►Insertion – Posterior surface of calcaneus via

tendocalcaneus (Achilles tendon)►Innervation –Tibial nerve (S1,2)►Action – Plantarflexes ankle, raises heel

during walking, flexes knee joint

►Mathes + Nahai Type I for each head Each head supplied by a sural artery, which arises from

popliteal artery at or slightly above the joint line and is 2-5cm long►Occasionally arises from common trunk, or lateral sural arises with

inferior lateral or middle genicular artery►Artery to medial head run directly to muscle►Artery to lateral head passes anterior to popliteal vein and tibial

nerve, may give off branches to plantaris and soleus as well as a small vessel accompanying surely nerve

3mm diameter with paired vc’s, one of which can be up to 4mm diameter

Enters each head at level of tibial condyles (pivot point), with nerves posterior to artery in 90% cases

Within the muscles each sural artery divides into two branches which run longitudinally between muscle fibre bundles and often subdivide further

►Medial head can reach to lower third femur, whereas lateral head has a smaller arc of rotation

Soleus

►Origin – Inferior end of lateral supracondylar line of femur and oblique popliteal ligament

►Insertion – Posterior surface of calcaneus via tendocalcaneus (Achilles tendon)

►Innervation –Tibial nerve (S1,2)►Action – Plantarflexes ankle and steadies leg

on foot

►Mathes + Nahai Type II muscle Dominant proximal supply from popliteal artery

branches and a secondary distal supply from branches of posterior tibial artery

Reverse flap has been described to cover heel defects, but it’s reliability is questionable

►Used to cover middle third tibial defects►Bipennate muscle, so can be split into larger

medial flap and a smaller lateral hemisoleus flap

Popliteo-posterior thigh flap► Inconstant vessel from proximal part of

popliteal artery, so Doppler assessment is important

► Generally reaches deep fascia 8-10cm above plane of knee with paired vc’s and ascends in midline May anastomose with br of inferior gluteal

artery that accompanies the posterior cutaneous nerve of the thigh

► Can raise flap as high as gluteal crease, and defect can be primarily closed if width < 10cm

► Arc of rotation allows coverage of patella, calf and sides of upper quarter of leg

► Elevation begins inferiorly, taking skin and deep fascia and septum between biceps femoris and semitendinosis

Lateral genicular flap

►Islanded flap based on cutaneous termination of superior lateral genicular artery, but may have some supply from inferior anastomotic (or Bourgery’s) artery

►Emerge along fascial septum, and then fan out above the iliotibial tract

►Unnecessary to raise iliotibial tract unless it is required in part of the reconstruction

Lower lateral thigh flap

►Essentially a lateral genicular flap with a broad pedicle overlying the lateral intermuscular septum that may incorporate the 4th PFPA

►Can raise flap up to 25cm long if at least two vessels, but 20cm vertically by 10cm horizontally is considered safe

►Raised leaving thin layer of loose areolar tissue over iliotibial tract to allow successful skin grafting

►Exposure and mobilisation of pedicle if required necessitates division of vastus lateralis and short head of biceps

(Lower) Posterolateral thigh flap

►Lower lateral thigh flap raised with a broad pedicle to include the vertical midline branch of the popliteal artery

Lower leg

Calf fasciocutaneous►Commonly raised on perforators

from posterior tibial arteries Emerge from between soleus and

FDL 5-6 perforators given off, tend to

be larger proximally Branch on reaching deep fascia

which spread anteroposteriorly and slightly inferiorly

►Can also be raised off peroneal artery from posterior peroneal septum

► Important to raise flaps with fascia. Generally only 3:1 . Can be distally based and/or islanded

Neurofasciocutaneous flaps► Sural or saphenous nerves► Rely on vasanervorum and vasovasorum

for supply of a distally based flap► Skin island marked along axis of sural nerve

and small saphenous vein, with rotation point 5-7cm above lateral malleolus

► Can raise up to 10x13cm flap with delay procedures

► Allows flap coverage without sacrificing major vessels

► Flap raised with deep fascia and SSV with subcutaneous pedicle 4cm wide. Medial sural nerve left intact

► Can be made sensate by inclusion of lateral sural nerve and retrograde dissection of adequate stalk length

► Useful in heel and Achilles tendon coverage

Fibular osteocutaneous flap► Type C osteofasciocutaneous flap► Nutrient vessel to the fibula is given off about 7cm from the origin of the

artery and penetrates the bone on the posterior or medial surface, posterior to interosseous membrane

► Nutrient foramen lies in middle third of bone on average 17cm from styloid process of fibula

► Cutaneous perforators pass along the posterior peroneal septum to reach the skin

► Can run through part of FHL +/- soleus, so most surgeons take a cuff of muscle posterior to septum in raising the flap

► Largest perforators lie between 10 and 20cm below the head of the fibula► Skin ellipse marked so that 1/3 is anterior to septum, 2/3 behind (max

dimensions are 5cm anterior, 10cm posterior), centered on 10-20cm below fibular head

► Posterior edge dissected first, then anterior, the bone mobilised► Distal 5cm of fibula should be left to maintain the ankle mortise► Can raise free fibula with epiphysis

Supramalleolar flap►Distally based flap raised on anterior perforating branch of

peroneal artery Pierces intermuscular septum about 5cm above lateral malleolus and

divides into deep br and superficial cutaneous br SCB emerges between EDL and peroneus brevis and directs branches

proximally to supply an area of 8x16cm►Planned around pivot point as described above, with lateral

border no further posterior than line of fibula►Adequate rotation may require a back cut in the line of the 5th

toe►Flap raised from anteromedial edge, preserving the

superficial peroneal nerve, then down to deep fascia

Lateral calcaneal flap►Based on the calcaneal branches of the peroneal

artery in the foot►Follows peroneus longus tendon about 1cm

posterior to it, 5-8mm anterior to Achilles tendon at the ankle down to 3cm inferior to tip of fibula before continuing to tuberosity of 5th metatarsal before anastomosing with lateral plantar artery

►Venous drainage of the area is via the lesser saphenous vein, and innervation by sural nerve (lies anterior to SSV)

►Can be raised islanded or reverse flow

Dorsalis pedis► Cutaneous supply of DP proper is a strip 2-3cm wide from extensor retinaculum to

half way along interosseous space Distal to this is supplied by 1st dorsal metatarsal artery, which lies beneath EHL tendon,

and can have a deep origin in up to 20% cases Lateral to this area is supplied by the lateral tarsal and arcuate arteries, which cannot be

included in the flap as they are deep to EDB and the long extensor tendons So usual flap plan relies on subcutaneous anastomoses between these supplies Distal end is prone to necrosis, so delay procedures are common

► Planned with proximal end of flap at inferior extensor retinaculum, distal end is proximal to web spaces, lateral extent is the borders of the foot

► Paired vc’s accompany the dorsalis pedis► Innervation of the area is by the superficial peroneal nerve, with 2PD 15mm► Plane of elevation must leave enough paratenon for split skin graft take► Transposition flaps utilising just the skin supplied by the 1st dorsal metatarsal

artery are useful in managing foot scars and local tissue loss, and reverse flow dorsalis pedis flaps can be used in managing midfoot amputation stumps

Lateral plantar► Posterior tibial artery consistently divides into medial and lateral plantar

branches at about the posterior edge of the sustentaculum tali► LPA gives off several calcaneal branches that pierce FDB and plantar

aponeurosis near the attachment to medial tubercle of calcaneus before running distally between FDB and flexor accessorius until lateral border of plantar aponeurosis

► The LPA supplies lateral border of 5th toe and curves medially to form the deep plantar arch

► Sensory innervation of the sole is by lateral plantar nerve in the lateral third and by medial plantar nerve in the medial two thirds

► This supply allows rotation/advancement flaps of the calcaneal branches or the entire lateral part of the sole to cover heel defects (FDB musculocutaneous flap) Has also been raised retrograde to cover 4th + 5th metatarsal heads

Medial plantar► MPA runs between abductor hallucis and FDB, and sends cutaneous supply to

medial sole via perforators that pass superior and (mainly) inferior to abductor hallucis

► Medial sole is innervated by medial plantar nerve (tibial nerve usually divides proximal to the posterior tibial artery, and the nerve usually runs medial to the artery)

► Venous drainage of the area is via the GSV and paired vc’s that accompany the MPA

► The flap is planned to avoid weight bearing areas and not to extend above the tuberosity of the navicular bone Lateral edge of abductor hallucis is the axis along which cutaneous perforators emerge,

and so the flap axis (surface marking is centre of heel to the medial sesamoid of the great toe, or the medial edge of the plantar aponeurosis)

Proximal incision to the sustentaculum tali may be required for dissection of the pedicle Flaps can be raised up to 10cm long x 7cm wide

► Flaps can be raised proximally or distally based, and in combination with lateral plantar artery

Toe flaps

►Multiple options based on plantar digital arteries and nerves Complete toe transfer (or paired toe transfer) Pulp transfer (+/- nail bed) Homodigital neurovascular island flap Composite PIP or MCP joint