Anterolateral thigh flap

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plastic & reconstructive surgery

Anterolateral thigh flap

  1. 1. Dr Subhakanta Mohapatra IPGME&R,Kolkata.INDIA
  2. 2. History by Song et al  1984 - 1st introduced  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. 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. 4. Contraindications  Previous surgeries  Injury to upper thigh  Morbid obesity – too thick flap – Difficult intramuscular dissection  Severe peripheral disease
  5. 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. 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. 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. 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.
  9. 9. Flap dimensions  Maximum length – 30 cm  Maximum width – 15 cm  For direct closure – maximum width – 8 - 10 cm or < 16% of thigh circumference
  10. 10. Muscles of antero lateral thigh
  11. 11. Vascular system of Anterolateral thigh & standard skin paddle
  12. 12. Standard flap design
  13. 13. 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
  14. 14. 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.
  15. 15. 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.
  16. 16. 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 )
  17. 17. Cutaneous perforator origin
  18. 18. 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
  19. 19. 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 .
  20. 20. 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.
  21. 21. ALT Flap Markings
  22. 22. Medial flap incision & septum identification
  23. 23. Opening of septum
  24. 24. Septum dissection distal to proximal
  25. 25. Medial retraction of RF & Identification of pedicle
  26. 26. Dissection of perforator & preservation of motor branches of femoral nerve
  27. 27. Final skin paddle & Readjustment
  28. 28. Medial retraction of RF & Identification of DLCFA
  29. 29. Skin incision
  30. 30. Incision of fascia
  31. 31. Exposure of vascular pedicle
  32. 32. Detachment of inter-muscular septum
  33. 33. Separation of pedicle components
  34. 34. Identification of perforator & distal ligation of pedicle
  35. 35. Circumcision of skin paddle
  36. 36. Fixation of skin paddle to muscle
  37. 37. Dissection of vascular pedicle
  38. 38. Cross section anatomy of flap
  39. 39. Flap ready for microvascular transfer
  40. 40. Myo-cutaneous flap containing 2 perforator
  41. 41. 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.
  42. 42. Disadvantages  Bulky flap  Hair bearing flap in male  Primary closure of donor site is not possible in most cases.
  43. 43. Post operative care  Removal of drain - output < 30 ml/day, with sero sanguinous discharge.  Encourage to walk on 3rd post op day.
  44. 44. 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 thighinjury 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.
  45. 45. Outcome & prognosis  Minimal long term donor site complications  Allowed to walk after 3 days  No significant decrease in strength or range of motion
  46. 46. 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
  47. 47. 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
  48. 48. ALT Failure Etiology  Inadvertent perforator divison at fascial plane  Inadvertent perforator injury during intramuscular dissection  Pedicle twisting during inset
  49. 49. Follow up – recipient area Aesthetic  Sagging of flap  Hair growth on flap  Contour defect  Flap bulkiness – need of debulking ( shoe wearing)
  50. 50. Follow up recipient area…. Functional  Speech problems  Oral incompetence  Eating problems  Facial pain  Nasal obstruction
  51. 51. Follow up – Donor area Aesthetic  Hypertrophic scar  Hypo/hyper pigmentation  Keloid  Contour defect
  52. 52. Follow up donor site…. Functional  Slightly limping gait  Sensory disturbances  Cold intolerance
  53. 53. Controversies  Anatomy – unpredictable  Dissection – difficult  Doppler identification of perforator is difficult.
  54. 54. Future  Emerged as new workhouse flap for soft tissue head & neck reconstruction.

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