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FRCS Plastic Surgery > CHAPTER 13: LOCAL, PEDICLED AND FREE FLAPS > Flashcards

CHAPTER 13: LOCAL, PEDICLED AND FREE FLAPS Flashcards

0
Q

Describe the different theories of the TRAM flap angiosomes.

A

Zone 1 - ipsilateral DIEA musculocutaneous perforators supplies the anatomical territory

Hartrampf 1982.
Zone 2 = contralateral to midline.

Holm 2006.
Zone 2 = lateral to zone 1 (anatomical territory of SCIA). Perfusion from DIEA crosses 1 set of choke vessels.
Zone 3 = contralateral to midline = dynamic territory.

Zone 4 - perfusion crosses 2 sets of choke vessels

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1
Q

Name the vascular plexuses of fascia, subcut tissue and skin.

A
  1. Subfascial - under deep fascia
  2. Prefascial - superficial to deep fascia. Main supply = fc vessels, predominant in limbs.
  3. Subcutaneous - superficial fascia. Main supply mc vessels, predominant in torso.
  4. Subdermal - main plexus supplying skin.
  5. Dermal - mainly arterioles, important in thermoregulation.
  6. Subepidermal - nutrition and thermoregulation.
    N.B. epidermis contains no blood vessels.
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2
Q

What is the delay phenomenon?

A 
Any preop manoeuvre that results in increased flap survival.
1. Increased axiality of blood flow.
2. Tolerance to ischaemia.
3. Sympathectomy vasodilatation theory.
4. Intraflap shunting hypothesis.
5. Hyperadrenergic state.
Unifying theory (Pearl) - all 5.
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3
Q

What is an angiosome?

A

A 3D composite block of tissue supplied by a named artery.

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4
Q

How is blood flow controlled by the muscular tone of vessels?

A
  1. Myogenic theory
    - pressure of blood within vessels (increased intraluminal pressure, vessels constrict).
  2. Neural innervation
    - sympathetic control of arterioles, AVAs and pre-capillary sphincters. (Cutaneous blood flow is reduced by increased tone of arterioles, decreased AVA tone and increased pre-capillary sphincter tone.)
  3. Humoral factors
    (- Epinephrine, norepinephrine, serotonin, TXA2, PG cause vasoconstriction.
    - Histamine, bradykinin and PGE1 cause vasodilatation, as does low O2, high CO2 and acidosis).
  4. Temperature - heat causes vasodilatation and increased flow through AVAs, bypassing capillaries.
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5
Q

How does blood reach the skin?

A
  • Deep vessels supply
  • Interconnecting vessels which supply
  • Vascular plexuses of fascia, sc tissue and skin.
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6
Q

Who are the names associated with describing angiosomes?

A

Manchot 1889.
Salmon 1930.
Taylor and Palmer - coined angiosome.

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7
Q

What is the onterconnecting system composed of?

A
  1. Fasciocutaneous (or septocutaneous) vessels
    - directly traverse fascial septa, e.g. limbs.
  2. Musculocutanous vessels
    - indirectly to skin via multiple perforating muscular branches, e.g. torso.
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8
Q

What are the anatomical, dynamic and potential territories of an artery?

A

Anatomical - area into which vessel ramifies before anastomosing with adjacent vessels.
Dynamic - area into which fluorescein extends into after injection into artery.
Potential - area that can be included if flap was delayed.

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9
Q

What are choke vessels?

A

Vessels that pass between anatomical territories.

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10
Q

How are flaps monitored?

A
  1. Clinical - subjective: colour, cap refill, warmth, turgor, scratch test
    Temp difference >3 degrees = significant
  2. Vital dye
    Fluorescein
  3. Photoelectric
    US doppler
    Doppler venous coupler
    Laser doppler
  4. Metabolic
    transcutaneous O2 tension (measures O2 partial pressures)
    Photoplethysmography - pulse ox, infrared light measures fluid vol by different light absorption by skin, disappointing results clinically
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11
Q

What is the theory of flap delay?

A

Flap delay: surgical interruption of a portion of the blood supply to a flap at a preliminary stage (10d - 3wks) before transfer

  1. Conditions flap to ischaemia
  2. Opens choke vessels

Tissue expansion is also form of delay

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12
Q

What different types of local flaps are there?

A
  1. Advancement
    - Simple e.g. Moberg
    - VY e.g. Atasoy, Venkataswamy / Evans step advancement (blood supply comes from deep tissue through a subset pedicle
    - Keystone - trapezoidal flaps used to close elliptical defects, blunt dissection maintains perforators, lateral deep fascial margin is incised to increase mobilisation, 2 ends of donor site are closed as VY advancements.
    - bipedicled (e.g. von Langenbeck mucoperiosteal flap, posterior auricular bipedicle flap)
    - Burrow’s triangle excision / Z plasty
  2. Pivot flaps with SSG of donor site
  3. Transposition flaps with direct closure of donor site e.g. rhomboid, Dufourmentel
  4. Interpolation flaps - flap raised from local bridge and pedicle is passed under / over skin bridge
  5. Rotation
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13
Q

What happens to blood flow when a flap is transferred?

A

Homeostasis is disrupted, including

  • loss of sympathetic innervation
  • ischaemia (anaerobic metabolism, lactate, superoxide radical, changes in blood viscosity and clotting)

Ischaemia induced reperfusion injury is direct cytotoxic injury from free radicals during flap ischaemia. Fat and bone can tolerate ~3hrs, muscle and GI mucosa much less.

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14
Q

Flaps to look up

A

lateral arm flap

dcia

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15
Q

How are muscle and musculocutaneous flaps classified?

A

Mathes and Nahai (1981 PRS).

  1. single pedicle.
  2. dominant and minor (unreliable) pedicles.
  3. 2 dominant.
  4. multiple segmental.
  5. 1 dominant, secondary segmental pedicles (can raise on either).
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16
Q

Compound and composite flaps

A 
Contains diverse tissue components
Solitary composite
Siamese
Conjoint
Sequential
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17
Q

Tell me about MC vs FC flaps

A

all demonstrate marked increase in blood flow
decrease in bacterial concentration MC>FC (count = 100 vs 10000)
collagen deposition MC>FC

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18
Q

How are flaps classified by composition?

A 
Cutaneous.
Fasciocutaneous.
Fascial.
Musculocutaneous.
Muscle.
Osseocutaneous.
Osseous.
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19
Q

Bone flaps

A

supplied by their nutrient vessels
can reconstruct large defects, withstand DXT and implantation
e.g. fibula (peroneal artery), radius (radial), iliac crest (DCIA)

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20
Q

Medial plantar flap - anatomy & usage

A

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
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21
Q

Who classified fasciocutaneous flaps?

A

Mathes
Direct cutaneous pedicle
Septocutaneous
Musculocutaneous

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22
Q

What are Langer’s lines and what did Borges describe?

A

Langer (19th century) made circular awl wounds in cadavers which resulted in elliptical defects due to skin tension.
Borges termed:
RSTL - parallel to rhytids, perpendicular to underlying muscle fibres.
LME - parallel to underlying muscle fibres, perpendicular to RSTLs.

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23
Q

Design a bilobed flap

A

Esser (1918) - 2 flaps designed 90 degrees to each other

Zitelli - 45 degrees

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24
Q

How do you classify flaps?

A 
Circulation.
Composition.
Contiguity.
Contour.
Conditioning.
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25
Q

What is a Z plasty?

What are the theoretical gains in length?

A

2 opposing triangular transposition flaps

Degrees            % gain in length
30                             25
45                             50
60                             75 
75                             100
90                             120
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26
Q

Who classified muscle flaps?

A 
Mathes and Nahai
I One dominant pedicle
II Dominant pedicle & minor pedicle (s)
III Two dominant pedicles
IV Segmental pedicles
V One dominant & secondary segmental pedicles
I TFL
II Gracilis
III Rectus abdominis, gluteus maximus
IV Sartorius
V Latissimus dorsi
27
Q

What are distant flaps?

A

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’

28
Q

Draw a 5 flap plasty.

A

BACED

29
Q

Draw a 4 flap plasty.

A

CADB

30
Q

Medial plantar flap - raising

A

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
31
Q

What factors contribute to increase flap survival?

A

Physical
warm, well filled, pain free

Pharmacological

  1. Anticoagulants: heparin, thrombolysis (streptokinase, t-PA), leeches
  2. Vasodilators: Ca channel blockers, topical GTN, topical lignocaine
  3. Antiinflammatory agents: aspirin
32
Q

What is a flap?

A

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:

  1. method of mvmt
  2. vascularity
  3. tissue composition
33
Q

Innervated flaps: functional muscle and sensory flaps

A

functional muscle: motor nerve coated after free flap transfer
e.g. gracilis, LD, serratus, pec minor

34
Q

What other flaps do you know of?

A

Neurocutaneous & venocutaneous flaps - based on perforating arteries accompanying cutaneous nerves and veins (e.g. sural, saphenous)

Venous flaps - supplied through a venous pedicle
Type I - single-pedicled: in & outflow through single vein
Type II - bipedicled ‘flow-through’ flap
Type III - arterialised venous flap: artery anastomosed to vein proximally and vein outflow distally

35
Q

How are perforator flaps classified?

How are they named?

A

Direct / indirect

  1. Musculocutaneous (indirect)
  2. Septocutaneous (indirect)
  3. 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

36
Q

How are flaps classified by contiguity?

A

Local - donor site adjacent to defect.
Regional - within the same region.
Distant.

37
Q

How do you classify flaps by circulation?

A

Random

Axial

  • direct (e.g. deltopectoral - IMA, groin - SCIA)
  • fasciocutaneous,
  • musculocutaneous,
  • venous.
38
Q

What are the risks of free fibula flap?

A
  • 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
39
Q

Cutaneous flaps: how are they classified?

A

McGregor and Morgan

  1. Random pattern: based off the subdermal plexus, limited to 3:1 length:width ratio
  2. 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

  1. cutaneous (equivalent to axial flap)
  2. fasciocutaneous
  3. adipofascial
  4. septocutaneous
  5. musculocutaneous
40
Q

Design a keystone flap

A

.

41
Q

What is the Mathes and Nahai classification of FC flaps?

A

Type A - direct cutaneous pedicle. e.g. groin, SIEA, dorsal metacarpal artery flaps.
Type B - septocutaneous. e.g. scapular, parascapular, lateral arm, PIA flaps.
Type C - musculocutaneous. e.g. median forehead, nasolabial, ALT (usually).

42
Q

What is a z-plasty?

A 
Transposition of 2 adjacent triangular flaps.
Purpose:
1. increase length of scar.
2. break up straight line scar.
3. realign scar.
43
Q

How are flaps classified by tissue composition?

A 
Fascial and fasciocutaneous flaps
Muscle and myocutaneous flaps
Vascularised bone flaps
Visceral flaps
Innervated flaps
Compound and composite flaps 
Prefabridcated flaps
44
Q

What is the fasciocutaneous plexus?

Who described the the different vessel types that perforate the deep fascia to supply the fasciocutaneous plexus?

A

A communicating network of subfascial, intrafascial, suprafascial, subcutaneous and sub dermal vascular plexuses

Nakajima

  1. direct cutaneous branch of a muscular vessel
  2. septocutaneous perforator
  3. direct cutaneous
  4. musculocutaneous
  5. direct septocutaneous
  6. perforating cutaneous branch of a muscular vessel
45
Q

What is the best orientation for a surgical incision?

A

Parallel to RSTL / rhytid.
Perpendicular to LMEs.
Parallel to direction of hair growth.
Pinch test.

46
Q

How are flaps classified by contour (how they are transferred into defect)?

A
  1. Advancement.
  2. Transposition.
  3. Rotation (in reality, flaps are rotated and transposed, i.e. pivot flaps).
  4. Interpolation (under or above intervening piece of tissue).
  5. Crane principle - transforms an ungraftable bed to graftable.
47
Q

How much does a z-plasty elongate a scar by?

A 
30 deg - 25%
45 deg - 50%
60 deg - 75%
75 deg - 100%
90 deg - 125%
Angles of flaps need not be equal but length of limbs do.
48
Q

What is the Cormack and Lamberty classification of FC flaps?

A

Type A - multiple FC vessels entering from base of flap e.g. Ponten.
Type B - single axial FC vessel e.g. scapular / parascapular flap, perforator DC flaps of lower leg.
Type C - multiple small perforating vessels from deep artery running along a fascial septum between muscles e.g. radial forearm, lateral arm flaps.
(Type C with bone).

49
Q

Give examples of each.

A
  1. gastrocnemius, TFL, ADM.
  2. trapezius, soleus, gracilis.
  3. rectus abdominis, pectoralis minor, gluteus maximus.
  4. sartorius, tibialis ant, long toe extensors and flexors.
  5. latissimus dorsi, pec major.
50
Q

When is a W-plasty used?

A

To break up linear scar to improve aesthetics, does not lengthen scar.

51
Q

Design a rotation flap

A
  • flap circumference should be 5-8x diameter of defect

- can design back cut, donor site closes directly by tissue redistribution

52
Q

How is blood flow to the skin regulated?

A

Systemic
1. Neural: sympathetic alpha adrenergic (vasoconstriction), beta adrenergic (vasodilatation). Cholinergic (bradykinin release, vasodilatation)
2. Humoral
Vasoconstriction: adr, noradr, serotonin, thromboxane A2, PGF2alpha
Vasodilatation: bradykinin, histamine, PGE1

Local (autoregulation)
Metabolic
Vasodilatation: hypercapnia, hypoxia, acidosis, hyperkalaemia

Physical
Vasoconstriction: myogenic reflex in response to distension of cutaneous vessels; local hypothermia and increased blood viscosity

53
Q

What are the 5 mechanisms of delay?

A
  1. Sympathectomy
  2. Vascular reorganisation
  3. Reactive hyperaemia
  4. Acclimatisation to hypoxia
  5. Non-specific inflammatory reaction
54
Q

Design a MacGregor flap

A

.

55
Q

Complications of free fibula flap

A
  • 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.
56
Q

What is a free flap?

A

a unit of tissue with an artery and vein is divided and reanastomosed at the recipient site with blood flow re-established

57
Q

Design a Limberg (rhomboid) flap

A

.

58
Q

Visceral flaps

A

e.g. jejunum, colon, omentum

59
Q

Prefabricated flaps

A

2 stage technique where flap is surgically altered by partial elevation, structural manipulation and incorporation of other tissue layers in the 1st stage to create a specialised composite flap
e.g. nasal recon

60
Q

How are venous flaps classified?

A

Thatte and Thatte.

  1. single venous pedicle.
  2. venous flow through flaps.
  3. arterialised venous flap (AVA proximally).
    e. g. saphenous flap (based on LSV), unpredictable, prone to congestion.
61
Q

What are the advantages and disadvantages of perforator flaps?

A

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

62
Q

what is an angiosome? Who described this?

A

Taylor and Palmer

- a composite unit of skin with its underlying deep tissue supplied by a source artery

63
Q

How do you design a z-plasty?

A
  1. Draw desired orientation of resultant scar (dotted).
  2. Draw line of original scar (bold).
  3. Draw 2 possible z plasty flaps, use ones with acute angle at apex of flap (not obtuse).
64
Q

What kinds of local flaps are there?

A

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

FRCS Plastic Surgery (63 decks)

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