CHAPTER 13: FLAPS Flashcards
Medial plantar flap - anatomy & usage
Cutaneous flap of glaborous skin
Artery - medial plantar perforator (landmark = medial cuneiform plantar surface) from medial plantar artery (from posterior tibial artery)
Veins - venae comitantes & superficial veins
Sensory - medial planatar or saphenous branch (if present)
Locate PT artery at behind medial malleolus Tom, Dick ANd Harry - from ant to post 1. Tib post 2. FDL 3. PT artery and tibial nerve 4. FHL
Flap usage
- small defects around medial malleolus, distal medial foot or medial first metatarsal head.
- Calcaneal defects if pedicle is traced back to PT
Medial plantar flap - raising
Flap 7 x 2cm
Doppler perforator
- flap can be designed eccentrically (if used for local rotation) or centrally (if free)
Axis of flap = plantar edge of the first metatarsal, first cuneiform, and navicular
- First incision made at plantar aspect of flap
- Enter fascia over abductor hallucis is entered
- Raise flap from plantar to dorsal
- Perforators between abductor hallucis and flexor hallucis tendons are identified and preserved
- abductor hallucis muscle is retracted and the perforators are followed to their origin on the medial plantar system
- superficial vein is traced from dorsal incision
- donor site closed directly / SSG
Flaps to look up
lateral arm flap
dcia
Complications of free fibula flap
- leave at least 6cm of proximal fibula to avoid destabilising knee and damage to common peroneal nerve
- CT angiography is recommended, as peroneal artery may be dominant in 8% patients (peroneal arteria magna) / the only perfusing artery in PVD or trauma pts
- identify and preserve lesser saphenous vein and sural nerve for skin paddle
can increase bone - bone contact with step / wedge osteotomy - Include cuff of soleus muscle or flexor hallucis longus muscle to improve reliability of skin paddle if skin perforators are small
- 6 to 8 cm of distal fibula must remain intact to stabilise ankle. In skeletally immature patients, perform a syndesmosis at the lateral malleolus following fibula harvest
Once fibula is visualised, dissection continues in a subperiosteal plane at superior margin of fibula until peroneal nerve is identified; then dissection may be continued superficial to periosteum to prevent iatrogenic deep peroneal nerve injury. - tibial nerve and posterior tibial artery must be identified before ligating vessels and harvesting flap
- keep operating field dry during dissection of FHL off the fibula and peroneal vessels, visualise and ligate all branching vessels from the peroneal bundle.
- ensure pedicle is not compressed, twisted or kinked. Use wide exposure of recipient site and inset under clear visualisation. Cover pedicle with SG if necessary
- After preparing fibula for inset, perform 1-2cm subperiosteal dissection to separate pedicle of flap and prevent kinking
- unicortical screws prevent pedicle injury.
What are the risks of free fibula flap?
- bleeding -> compartment syndrome
- damage to common? deep / superficial peroneal nerve
- sural nerve sacrificed - parasthesia lat foot and leg
- swelling, lymphoedema
- stiffness
- unstable ankle - problems with running
- flap failure
What is a flap?
A unit of tissue that maintains its own blood supply while being transferred from a donor site to a recipient site.
Most flaps can be classified according to:
- method of mvmt
- vascularity
- tissue composition
What kinds of local flaps are there?
Advancement - slides directly forward into defect
Rotation - semicircular flap rotated about a pivot point into a defect to be closed
Transposition - rotated laterally about a pivot point into an immediately adjacent defect
e.g. Z plasty, rhomboid (Limberg), Dufourmentel
Interpolation - rotates on a pivot point into a defect, with pedicle passing over or under intervening tissue e.g. deltopectoral, Littler NV digital pulp flap
What is a Z plasty?
What are the theoretical gains in length?
2 opposing triangular transposition flaps
Degrees % gain in length 30 25 45 50 60 75 75 100 90 120
What are distant flaps?
where donor and recipient sites are not close to one another
e.g. thenar, cross-leg, groin
When 2 sites cannot be approximated, flap can be ‘waltzed’
What is a free flap?
a unit of tissue with an artery and vein is divided and reanastomosed at the recipient site with blood flow re-established
what is an angiosome? Who described this?
Taylor and Palmer
- a composite unit of skin with its underlying deep tissue supplied by a source artery
What is the fasciocutaneous plexus?
Who described the the different vessel types that perforate the deep fascia to supply the fasciocutaneous plexus?
A communicating network of subfascial, intrafascial, suprafascial, subcutaneous and sub dermal vascular plexuses
Nakajima
- direct cutaneous branch of a muscular vessel
- septocutaneous perforator
- direct cutaneous
- musculocutaneous
- direct septocutaneous
- perforating cutaneous branch of a muscular vessel
Cutaneous flaps: how are they classified?
McGregor and Morgan
- Random pattern: based off the subdermal plexus, limited to 3:1 length:width ratio
- Axial pattern: contains a specific direct cutaneous artery within the longitudinal axis of the flap
(3. Reverse axial pattern flaps (reverse flow flap)
4. Island flap)
Nakajima: classified cutaneous flaps based on vascularisation
- cutaneous (equivalent to axial flap)
- fasciocutaneous
- adipofascial
- septocutaneous
- musculocutaneous
How are perforator flaps classified?
How are they named?
Direct / indirect
- Musculocutaneous (indirect)
- Septocutaneous (indirect)
- Direct cutaneous (direct)
Named after nutrient vessel (e.g. DIEP) unless multiple flap can be raised from the nutrient vessel e.g. ALT flap from descending branch of lat circ femoral
What are the advantages and disadvantages of perforator flaps?
Adv
numerous donor sites, versatile size and thickness
can incorporate muscle, fat bone into flap design
preserve muscle function
reduce donor site morbidity
Disadv
tedious pedicle dissection
perforator anatomy variable
increased risk of fat necrosis cf musculocutaneous flaps
