anterolateral thigh flap

1. Dr sumer singh
Plastic and reconstructive deptt

2. History 1984 - 1st introduced by Song et al
 1986 - for head & neck reconstruction 1st described by
Koshima et al
 1992 – 1st microvascular transfer of VL muscle flap –
Wolff
 1995 – for lower extremity defect
 1996 – ultrathin flap (3-4 mm) preserving subdermal
plexus – Kimura et al
 Very popular reconstructive flap in Asia
 Limited use in West –
vascular anatomy variations
difficult dissection
thick thigh fat

3. Indications
Head & neck reconstructions
 Buccal mucosa defect
 Buccal through & through defect
 Pharyngo-oesophageal reconstruction
 Lower lip
 Tongue
 Lateral & anterior skull base
 Scalp
 Combined with free fibula flap
Extremity reconstruction

4. Contraindications
 Previous surgeries
 Injury to upper thigh
 Morbid obesity – too thick flap – Difficult
intramuscular dissection
 Severe peripheral disease

5. Types
 Free flap
 Pedicled flap
 Distally based (on distal minor pedicle) – for knee defect
 Proximally based –
 Trochanteric bed sore
 Lower abdominal defects
 Perineal reconstruction
 Gluteal defect

6. Types
 Type B/C Fasciocutaneous flap (type B - septocutaneous
perforator) or ( type C - musculocutaneous perforator )
 Musculocutaneous flap
 Fascial flap
 Adipo fascial flap – for Romberg disease
 Sensate flap(include lateral femoral cutaneous nv.)
 Osteo fascio cutaneous flap
 Chimeric flap ( 2 or more separate defect)
 2 small independent flaps
 Muscle only flap
 Flow through flap (to salvage extremity, where proximal &
distal ends of pedicle anastomosed to recipient vessel)

7. Pre-Op preparation
 Exclude previous trauma/surgery to thigh
 Doppler study over
 lateral intermuscular septum
 2-3 cm lateral to lateral intermuscular septum(over
medial part of VL)
 Angiography - not helpful
 Check for popliteal pulsation
 Consent for - failure/risk/alternate (RFFF)
 Donor site morbidity, knee instability / limping gait
 No IV line in flap leg

8. Landmarks
 Line drawn between ASIS & supero-lateral border of
patella
 Corresponds to the septum between RF & VL.
 Skin perforators mapped by Doppler
 Accuracy of Doppler decreases as BMI increases.

10. Flap dimensions
 Maximum length – 30 cm
 Maximum width – 15 cm
 For direct closure –
maximum width – 8 - 10 cm or < 16% of thigh
circumference

12. Muscles of antero lateral thigh

13. Vascular system of Anterolateral thigh &
standard skin paddle

14. Standard flap design

15. Flap harvesting
 Initial skin incision on medial flap aspect over RF , 2-3
cm medial to lateral inter-muscular septum.
 Proximal incision between TFL & RF
 Sub-fascial – incision through deep fascia with lateral
dissection until perforators identified
 Supra-fascial - for thin flap carried laterally until
perforators identified

17. Flap harvesting
 Skin incision completed after perforator identification
 Retrograde dissection of pedicle to descending
branch
 May involve dissection of VL. A cuff of muscle may be
left to protect perforating branches.
 Advantage of taking a part of VL
easy harvest – no intramuscular dissection
pedicle twisting will be less
 Lateral femoral cutaneous nerve – sensate flap
 Thinning performed in deep fat layer to avoid pedicle
injury.

20. Pedicle
 1 Artery, 2 Venae commitantes, motor branch of
femoral nerve to VL
 Based on perforators from descending branch of
lateral circumflex femoral artery (90%).
 From transverse branch of LCFA (4%).
 From profunda femoris (4%) – pierces through RF.
Descending branch
 Can be safely dissected proximally to its major
branch to RF, which should be preserved
 Runs in inter-muscular space b/w RF & VL.
 Terminates by anastomosing with superior lateral
genicular artery.

21. Dimensions of vascular pedicle
 Average length of pedicle – 12 cm
 Diameter ( DLCFA )
 Artery - 1.5 – 2.5 mm ( Avg - 2.1 mm )
 Veins – 1.8 – 3.3 mm ( Avg - 2.3 mm )

22. Cutaneous perforator origin

23. Perforators
 Mapping – A (most proximal),B, C (most distal)
 Musculocutaneous perforator (80-90%) - traverse
VL (close to medial edge) & deep fascia to supply skin
 Septocutaneous perforator (10-20%) –
 runs in-between RF & VL
 pierces the fascia lata to supply skin

24. Perforator classification
 Type 1 (50 %) –
Perpendicularly to subdermal
plexus.
 Type 2 (35%) –
Branch in adipose & extends into
subdermal plexus.
 Type 3 (15%) –
Extends along deep fascia &
gradually into adipose .

25. Sensory innervations
Lateral femoral cutaneous nerve(L2-L3)
 Direct branch of lumbar plexus
 Enters thigh deep to IL near ASIS.
 Follows path of deep circumflex iliac artery & vein
 Lies along line connecting ASIS to lateral patella.
 Pierces fascia lata 10 cm distal to IL.
 Travels in deep subcutaneous layer immediately
superficial to deep fascia.

26. ALT Flap Markings

27. Medial flap incision & septum
identification

28. Opening of septum

29. Septum dissection distal to proximal

30. Medial retraction of RF &
Identification of pedicle

31. Dissection of perforator &
preservation of motor branches of
femoral nerve

32. Final skin paddle & Readjustment

33. Medial retraction of RF &
Identification of DLCFA

34. Skin incision

35. Incision of fascia

36. Exposure of vascular pedicle

37. Detachment of inter-muscular
septum

38. Separation of pedicle
components

39. Identification of perforator & distal
ligation of pedicle

40. Circumcision of skin paddle

41. Fixation of skin paddle to muscle

42. Dissection of vascular pedicle

43. Cross section anatomy of flap

44. Flap ready for microvascular
transfer

45. Myo-cutaneous flap containing 2 perforator

46. Advantages
 Minimal long term donor site morbidity
 Long,reliable,larger pedicle
 Large skin paddle
 Can cover complex wound
 Good pliability
 No major artery is sacrificed
 Ability to tailor the thickness of flap.

47. Disadvantages
 Bulky flap
 Hair bearing flap in male
 Primary closure of donor site is not possible in most
cases.

48. Post operative care
 Removal of drain - output < 30 ml/day, with sero
sanguinous discharge.
 Encourage to walk on 3rd post op day.

49. Post op complications
Recipient site
 Flap necrosis
 Fistula (head & neck
reconstruction )
 Haemorrhage
 Arterial occlusion
 Local abscess
 Exposed bone/plate
Donor site
 STSG loss
 Wound infection
 Dog ears
 Pain & weakness in thigh-
injury to nerve to VL.
 Seroma/haematoma
 Partial necrosis of foot &
calf –
in a case of DLCFA act as a
critical collateral for an
obstructed superficial
femoral artery.

50. Outcome & prognosis
 Minimal long term donor site complications
 Allowed to walk after 3 days
 No significant decrease in strength or range of motion

51. ALT vs Radial forearm free flap
ALT
 Increased learning curve
 Primary closure
 Morbidity related to vastus
lateralis damage
 Potential dysfunction –
Quadriceps
Pain
Disto-lateral thigh
anaesthesia /paraesthesia
Radial forearm free
flap
 Potential tendon exposure
 Sacrifice of dominant
distal blood supply
 Closure with STSG
 Potential dysfunctions -
Hand stiffness
Pain
Anaesthesia / paraesthesia

52. Anatomical Variations
 Absence of cutaneous perforator – in 5.4 %
 Absence of descending branch – in 22.6 %
replaced by medial descending branch
( inominate branch )
 Ascending branch can supply a perforator to upper
part of ALT, which can be used when normal ALT
perforators are inadequate
 Other leg can be used

53. ALT Failure Etiology
 Inadvertent perforator divison at fascial plane
 Inadvertent perforator injury during intramuscular
dissection
 Pedicle twisting during inset

54. Follow up – recipient area
Aesthetic
 Sagging of flap
 Hair growth on flap
 Contour defect
 Flap bulkiness – need of debulking ( shoe wearing)

55. Follow up recipient area….
Functional
 Speech problems
 Oral incompetence
 Eating problems
 Facial pain
 Nasal obstruction

56. Follow up – Donor area
Aesthetic
 Hypertrophic scar
 Hypo/hyper pigmentation
 Keloid
 Contour defect

57. Follow up donor site….
Functional
 Slightly limping gait
 Sensory disturbances
 Cold intolerance

58. Controversies
 Anatomy – unpredictable
 Dissection – difficult
 Doppler identification of perforator is difficult.

59. Future
 Emerged as new workhouse flap for soft tissue head
& neck reconstruction.