Eur J Plast Surg (1990) 13:2-6

European " •

am °' Plastic bufgery © Springer-Verlag 1990

Inferiorly based lateral thigh f lap- a new skin flap (ILT-flap) K. I m a i , T. I n o u e , M . H a t o k o , I. T a n a k a a n d T. H a r a s h i n a

Department of Plastic and Reconstructive Surgery, Saitama Medical Center, Saitama Medical School, 1981 Kamoda, Tsujido, Kawagoe, Saitama, 350 Japan

Summary . F l a p s o f the la te ra l th igh a rea have been de- scr ibed; a new infe r io r ly based la te ra l th igh f lap is pre- sented. E x a m p l e s o f two pa t ien t s t r ea ted wi th this f lap are p resen ted . One d e m o n s t r a t e s the use o f the f lap as a ped ic led i s land and the o the r as a free flap. Bo th f laps p r o v i d e d a sa t i s fac to ry end result . The ope ra t ive tech- n ique and the f lap b l o o d supp ly us ing pre- and p o s t o p e r - a t ive a n g i o g r a p h y are descr ibed.

Key words: La te r a l th igh f lap - C u t a n e o u s b r a n c h Popl i t ea l a r t e ry A n g i o g r a p h y

A new la te ra l th igh skin f lap has recent ly been des igned; it is ba sed on the th i rd a n d fou r th p e r f o r a t i n g ar ter ies o f the deep femora l ar tery .

The fou r th p e r f o r a t i n g a r t e ry somet imes arises f rom the t e rmina l p e r f o r a t i n g b r a n c h o f the deep f emora l ar- tery; it a n a s t o m o s e s above wi th the m o r e p r o x i m a l per- fo ra t ing ar ter ies and be low wi th the cu t aneous b ranches o f the pop l i t ea l ar tery . A c o m p o s i t e defect a r o u n d the knee was r econs t ruc t ed wi th an in fe r io r ly based la te ra l th igh f lap which was supp l i ed by the cu t aneous b r a n c h o f the pop l i t ea l ar tery. This f lap can be used as a free flap.

Case 1

A 42-year-old woman presented with a composite tissue defect of her left lower leg resulting from a traffic accident in May, 1988. For about one month her wound was treated with dressing with no improvement, thus it was decided to close the defect surgically. At operation, the scar and necrotic tissue were excised down to a healthy bone producing a 7 x 4 cm defect over the knee. An inferiorly based lateral thigh skin flap was designed, the dimensions were 5 cm wide and 13 cm long. This flap was vascularized by the cutaneous branch of the popliteal artery, which lies 7 cm above the knee (Fig. 1). The medial skin incision was made through the subcutaneous tissue of the lateral thigh. The flap was then raised

in a proximal direction, leaving the underlying fascia intact (Fig. 2). The cutaneous branch of the popliteal artery was identified, enter- ing the flap 3 cm below the fourth perforating vessels (Fig. 3).

The viability of the flap was shown by good marginal bleeding and good capillary refill. The flap could be transposed easily into the knee defect, and the donor site area was closed by primary suture. The flap healed without complications. Six months after the operation, the results are satisfactory (Fig. 4).

Investigation of flap blood supply

Using the Doppler ultrasound, the vessel can be located 7 cm proxi- mal to the knee joint. In 40 lower limbs, this point was found to be between 6 cm and 8 cm proximal to the knee joint.

Angiography

Angiography of the left thigh was performed in the preoperative planning and postoperative follow-up (Figs. 5, 6). This study showed that the blood supply to the inferiorly based lateral thigh flap is through the cutaneous branch of the popliteal artery.

Case 2

A 52-year-old woman presented with an osteomyelitis over her left elbow (Fig. 7). After debridement an inferiorly based lateral thigh flap, measuring 20 x 6.5 cm, was raised (Fig. 8). An end to end anastomosis of the flap artery to a branch of the radial artery was performed with an end to end anastomosis of the veins. The flap artery had a diameter of 2 mm. The flap was well perfused and the donor defect was dosed primarily (Fig. 9), healing was uneventful (Fig. 10).

Postoperative angiography of popliteal artery (Fig. 11). The direct cutaneous branch of popliteal artery is absent having been taken as the supply to the free flap.

Discussion

It is diff icul t to cover a c o m p o s i t e t issue defect a r o u n d the knee. Thus, m a n y m e t h o d s for its r econs t ruc t ion

Fig. 1. Composite tissue defect of the knee and the design of the inferiorly based lateral thigh flap

Fig. 2. The flap was raised, without including the fascia

Fig. 3a, b. The direct cutaneous branch of popliteal artery entered the flap 3 cm below the fourth perforating artery

Fig. 4. Six months after operation. The flap survived completely

have been described (skin graft, pedicled flap, and free flap) [2, 3, 8, 1~15].

The cutaneous blood supply of the thigh has been reported by several authors [1, 4, 5, 7, 11, 12, 15]. The anterolateral and posterior thigh region are supplied by the deep femoral artery [6, 7]. The lower third of the posterolateral thigh is supplied by the direct popliteal

and lateral superior genicular cutaneous branch [11]. The cutaneous branch of the popliteal artery anasto- moses with the terminal branch of the deep femoral ar- tery [1, 5]. Therefore, a flap pedicled on the cutaneous branch of the popliteal artery can be raised.

In result of a selective arterial injection study and an injection study with blue ink, Laitung [11] stated

---profunda femoral artery

Iperforator

Fig. 5. Preoperative angiography of the deep femoral artery

Fig. 6. a Postoperative angiography of the popliteal artery (left) and deep femoral artery (right). b Diagram of the angiographic findings

direct cutaneo branch

popliteal after:

b

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)far

that it is possible to raise a fasciocutaneous flap pedicled on the popliteal cutaneous branch. It is our impression that the flap can be raised without the fascia, because of the good subcutaneous vascular network in the subcu- taneous area of the thigh [6, 7, 9, 10].

In our cases, the flaps were raised as a pedicled island flap and a free flap without including the underlying

fascia. As a result of this the flap was very thin. The survival length is shown in Fig. 12, which also illustrates the arc of the rotation.

This flap artery has a diameter of about 2 mm at its origin from the poplitcal artery and the length of its pedicle is about 10 cm, thus, the flap can be conven- iently used as a free flap.

Fig, 7. Osteomyelitis of the left elbow joint

Fig. 8. a The inferiorly based lateral thigh flap was designed, 6.5 cm wide and 20 cm long. b The flap was vascularized by the direct cutaneous branch of the popliteal artery

Fig. 9. a An end to end anastomosis of the flap artery to the branch of the radial artery. The flap appeared well-vascularized, b The donor defect was closed primarily

Fig. 10. The flap survived completely after one month

Fig. 11. Postoperative angiography of the popliteal artery; a r r o w

shows the superior lateral genicular artery. The direct cutaneous branch of the popliteal artery is absent

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Fig. 12. Diagram of the arc of the rotation of the lateral thigh flap

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Co, Boston, 3rd edn, p 1835 2. Arnold PD (1981) Vastus medialis muscle flap for functional

closure of the exposed knee joint. Plast Reconstr Surg 68 : 69 3. Barclay TL (1983) Cross-leg fasciocutaneous flap. Plast Re-

constr Surg 68 : 69 4. Back SM (1983) Two new cutaneous free flap : the medial and

lateral thigh flaps. Plast Reconstr Surg 71:354 5. Clemente CD (1985) The blood supply of thigh skin. Plast

Reconstr Surg 75 : 342 6. Cormack GC (1985) The blood supply of thigh skin. Plast Re-

constr Surg 75 : 342 7. Cormack GC (1986) The arterial anatomy of skin flaps. Chur-

chill Livingstone, Edinburgh, i st edn, p 208 8. Elsahy NL (1978) Cover of the exposed knee joint by the lateral

head of the gastrocnemius. Br J Plast Surg 31:136 9. Grotting JC (1986) Regional blood supply and the selection

of flap for reconstruction. Clin Plast Surg 10. Inoue T (1985) Our clinical experiences with the lateral thigh

flap. Jpn J Plast Reconstr Surg 28 : 567 11. Laitung JK (1989) The lower posterolateral thigh flap. Br J

Plast Surg 42:133 12. Maruyama Y (1989) Popliteo-posterior thigh fasciocutaneous

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type of flap for defects of the knee. Br J Plast Surg 38:512 14. Petty GT (1978) Closure of an exposed knee joint by use of

sartorius muscle flap. Plast Reconstr Surg 62 : 458 15. Quaba AA (1988) Extended application of the biceps femoris

musculocutaneous flap. Plast Reconstr Surg 81:94