The anterolateral thigh (ALT) flap is a versatile soft tissue flap that can be used as a pedicled or free flap for reconstruction. It is supplied by septocutaneous or musculocutaneous perforators from the lateral circumflex femoral artery. The ALT flap is commonly used to reconstruct defects of the head and neck, extremities, breast, and perineum due to its long pedicle and ability to provide skin and soft tissue with or without muscle. While it has many advantages like long pedicle length and versatility, disadvantages include potential skin grafting at the donor site and contour abnormalities.

1. Anterolateral thigh (ALT) flap

2. Introduction
• The anterolateral thigh (ALT) free flap was first described by Song et al. in 1984
as a soft tissue flap that is perfused by septo-cutaneous branches of the lateral
circumflex femoral artery (LCFA).
• It is a Fasciocutaneous flap (type B – Septo-cutaneous perforator) or ( type C -
musculocutaneous perforator )

3. Work horse flap for reconstruction
• As a Pedicled flap
 Distally based (on distal minor pedicle) – for knee defect
 Proximally based –Trochanteric bed sore, Lower abdominal defects
Perineal reconstruction , Gluteal defect.
• As a Free Flap
 Buccal mucosa defect ,Buccal through & through defect , Pharyngo-
oesophageal reconstruction ,Lower lip ,Lateral & anterior skull base,
Scalp defects , breast reconstruction , Extremity reconstruction ,
Phalloplasty etc.

4. Flap supply
• ALT flap is supplied by either septocutaneaus vessels (87%) or
musculocutaneaus perforators (13%) from the descending branch of
LCFA.
o Length : 12 cm (range 8-16 cm )
o Diameter : 2.1 mm (range 2-2.5 mm)
Two venae comitantes accompanies the pedicle
Lateral femoral cutaneous nerve (L2-L3) provide the sensory innervation to the
area

6. Pre-op Evaluation
• Functional evaluation of knee extension
• Previous scar that may affect flap design
• Marking of perforator by Doppler
• Prior skin graft donor sites can be incorporated as part of the flap

7. Important landmark ASIS and
superior lateral border of patella
Perforators are located at this drawn line
• The ASIS to lateral patella (Septocutaneus)
• Posterior to this line (Musculocutaneaus)

8. Flap harvest
• Medial incision first and subfascial
approach.
• Rectus femoris is identified by its
bipinnate arrangement of fibers around
central raphe.
• Septum is identified between RF and VL.
• By doing medial retraction , Any Septo-
cutaneous Perforator should be visualized
by now.

9. • If No perforator is visualized the
deep fascia should be dissected off
the VL.
• And still no perforator is visualized
incision can be extended superiorly
or inferiorly to search for a
perforator.
• When the perforator is found ,then
only the dissection proceeds.
• The perforator is dissected to its
source pedicle .

10. • All Possible nerves to
vastus lateralis and the
muscle itself should be
preserved.
• Once the anterior
dissection is complete ,lateral
incision can be taken.

12. Flap modification
• Thin Flap
• Adipofascial flap
• Innervated flap
• Functional muscle flap
• Flow through flap
• Chimeric

13. Advantages Disadvantages
Ease of harvest Colour mismatch in facial reconstruction
Long length and large pedicle Presence of hairs in male patients
Versality in design Skin graft at donor site (>8cm width of the flap)
Ablity to provide sensory innervation Excess flap bulk required secondary de-bulking
Less donor site morbidity Fistula and stricture in pharyngeal reconstruction
Less operative time with two team approach Breast reconstruction- fat necrosis

14. Clinical examples

17. Pedicled ALT flap cover Proximally based and distally based for Trochantric sore and knee defect

18. Thank you