Eur J Plast Surg (1989) 12:103-107
European l l l l l Journal of glflStle Springer-Verlag 1989
The Free Lateral Thigh Flap
W.-X. Guan, K.-X. Cheng, Y.-H. Zou, Y.-T. Jin, Y.-L. Qian and T.-S. Chang Department of Plastic and Reconstructive Surgery, Ninth People's Hospital, Shanghai Second Medical University, Shanghai, People's Republic of China
Summary. Experience with 13 free lateral thigh flaps is presented. In only one case was there necro- sis and this was partial. The method of raising the flap is described in detail and the advantages and disadvantages are described. This flap is more difficult to raise than the medial thigh flap and care must be taken in searching for its supplying vascular pedicle.
Key words: Lateral thigh flap - Free tissue transfer - Cutaneous branch
The free lateral thigh flap was designed and re- ported simultaneously with the free medial thigh flap by Baek  in 1983. Since 1983, using Baek's experience as our guide, both flaps were used si- multaneously in clinical cases. The experience with the medial thigh flap has been reported elsewhere . This paper presents the experience with the lateral thigh flap in 13 clinical cases (Table 1).
Dissection of the Flap (Fig. 1)
In order to shorten operating time, two teams work simultaneously, one raising the flap and the other preparing the recipient site. According to Baek's description, the vessels that supply the lateral thigh flap are a cutaneous branch of the third perforat- ing branch of the profunda femoral artery and its accompanying vein. These vessels emerge at the midpoint of the femur between the greater tro- chanter and the lateral epicondyle. First a point is marked at the posterior border of the fascia lata, midway between the tip of the greater trochanter and the lower border of the lateral epicondyle of the femur. A paper pattern of the defect is made
and placed on the lateral thigh in such a way that two-thirds of its width lies posterior and two-thirds of its length lies distal to this point. The outline of the required flap is drawn out, increasing its size by 1 cm around the periphery. The skin inci- sion is first made along the anterior border of the flap outline and carried down to a plane just super- ficial to the fascia lata. From this incision and re- maining in this plane the flap is dissected towards the posterior border of the fascia lata. When the latter is reached, dissection ceases and the anterior half of the flap is reflected backwards. With the help of magnifying loupes, we look carefully along the posterior border of the fascia lata for the sup- plying artery and vein. Usually they emerge at a lower level than the presumed site in our series. They are traced proximally until a length of 4 cm or longer is gained. The fat around the vessels is
Fig, 1. Design of the flap. X represents the site where the un- named artery emerges, which is situated at a point midway between the tip of greater trochanter and the distal border of lateral condyle of the femur. The oval figure represents the outline of the flap, designed in such a way that two-thirds of its width is located posterior to and two-thirds of its length is located distal to the X
Table 1. Clinical data of 13 cases
Case Sex Age Preoperative status Op. date no.
Flap Caliber Caliber Result size artery vein survival (cm) (ram) (ram) rate
1 M 33 Scar contracture 20.9.83 of thumb webspace
2. M 34 Scar contracture over 19.10.83 dorsum of right hand
3 M 17 Scar contracture over 24.10.83 dorsum of right hand
4. M 21 Scar contracture over 25.10.83 right wrist
5. M 27 Scar contracture over 21. 2.84 left wrist
6. M 23 Scar contracture over 21. 2.84 left wrist
7. M 22 Ulceration of right 27. 3.84 heel
8. M 36 Scar contracture over 18. 4.84 left thumb webspace
9. F 34 Scar eontracture over 10. 7.84 dorsum of left hand
10. M 21 Adhesive scar over 13. 9.84 left frontal region
11. M 49 Unstable scar over 21. 6.85 dorsum of left foot
12. M 22 Scar contracture over 11. 6.86 left thumb webspace
13. M 29 Scar over radial dorsum 18. 6.86 of right hand
6 x 8 0.8 1.2 100%
13 x 8.5 1.5 2.5 100%
10 x 8.5 1.5 4.0 100%
8 x 9 1.5 2.0 100%
22 x 7 1.6 2.0 Necrosis of distal 4x5cm
15 x 5.5 1.0 2.5 100%
14.5 x 7 1.5 1.5 100%
11 x 5 1.0 1.5 100%
18 6.5 1.2 2.0 100%
12 x 7 1.0 1.0 100%
6.5 7.5 0.8 1.0 100%
11 6 0.8 0.7 100%
8 x 7 0.8 1.0 100%
cleared away. The skin incision is now completed along the posterior border of the flap outline and the remaining half of the flap is elevated in the same plane. Now the flap is attached to the lateral thigh only by its vascular pedicle. The whole flap is wrapped in moist, warm sponges for five to ten minutes. The sponges are removed and the flap is inspected to make certain that its blood supply is adequate. By this time the recepient site is usual- ly ready. The vascular pedicle of the flap is divided and the flap is transferred to the defect. It is se- cured in place by a few sutures at its edge. Vascular anastomosis is carried out under the operating mi- croscope, usually with 10 x magnification. The do- nor site can usually be closed by direct approxima- tion. If not, a skin graft is applied.
The lateral thigh flap has virtually the same merits as those stated for the medial thigh flap in the authors' previous paper. However, when judged by the authors' overall experiences with these two flaps, the lateral thigh flap has some advantages over the medial thigh flap. These arc as follows:
1. The lateral thigh flap has thinner subcutaneous fat than the medial thigh flap and can thus achieve a better cosmetic result. 2. No important structures are encountered during dissection of the lateral thigh flap; therefore, there is less risk for local injury. 3. The caliber of the vessels is usually larger than that of the medial thigh flap. 4. When a longer flap or vascular pedicle is re- quired, one can design the flap at a lower level and then trace the vessel upward to gain more length. The longest pedicle was 10 cm in this series. This possibility does not exist in the medial thigh flap.
There are some less important shortcomings of the lateral thigh flap: 1. The skin is somewhat hairy and darker. 2. Direct closure of the donor wound may some- times be difficult if a larger flap has been harvested. 3. The guidelines for locating the vascular pedicle are not as clear cut as for the medial thigh flap because the latter has the superficial femoral artery as a guide in dissection.
The lateral thigh flap used in our series lies in a more oblique position to the axis of the thigh
Fig. 2a-f. Case 3. a Preoperative volar view. Scar contracture of the right thumb webspace and loss of ring and little fingers. b The scar has been excised and the thumb webspace widened. The extensor pollicis longus is partially exposed, e The lateral thigh flap has been developed with the vascular pedicle still attached. The size of the flap was 10 x 8.5 cm. d The donor site was closed by approximation except for a small area which was skin grafted, e The donor site of the flap three weeks after operation, f The flap three weeks after operation; the function of the thumb was restored
Fig. 3a-d. Case 10. a Preoperative view. Unstable adhesive scar over the left temporal and frontal region due to massive scalp necrosis caused by auromyocine intravenous infusion given when he was one year old. b The supplying vessels have been dissected out and the outline of the flap is shown. c Postoperative view ten days after operation. The flap survived well. d Postoperative view one year after operation
Fig. 4a-h. Case 11. a Postburn unstable scar on the dorsum of the left foot of 15 years' duration with central ulceration. b The burn scar has been excised and the dorsalis pedis artery dissected out as the recipient artery. c The donor site of the flap. X represents the presumed site where the nourishing vessels emerge. d The flap has been completely developed, ready to be transferred. e The donor site has been closed by approximation. f The flap in place just after completion of the operation. A piece of rubber sheeting is inserted for drainage. g Postoperative view one month after operation. h Postoperative view of donor area one month after operation
than that described by Baek. As stated before, it is our routine to dissect out the vascular pedicle first and then redesign the outline of the flap ac- cording to the course of the vessels so as to increase the blood supply for the flap. This perhaps ac- counts for the variation in the flap outline. (Figs. 2-4).
It is interesting to mention that in our first case there were two cutaneous branches supplying the flap, one at the upper third and the other at the lower third. The upper one had a caliber of about 0.8 mm for the artery while its accompanying vein was 1.2 mm in diameter. In the lower one the ar-
tery had a greater caliber, being about 1.2 mm in diameter, but its accompanying vein was too tiny- only 0.5 mm in diameter. After careful considera- tion, we decided to use the upper pedicle because, as is well known, inadequate venous drainage has been the cause of flap failure in most cases. Before ligating the lower branch, it was clamped tempo- rarily for ten minutes to make sure that the upper one could adequately supply the flap. This proved to be the correct choice, as evidenced by the un- eventful postoperative course and the complete survival of the flap.
The fifth case had a partial loss of the distal
portion of the flap. There might be two factors to account for this. Firstly, the flap was the longest one in this series (22 x 7 cm), and secondly, it not only covered the wound on the wrist, but also the wound on the first webspace and hence some kink- ing of the distal portion occurred. In light of this experience, it is suggested that the length of the flap should not exceed 20 cm.
In order to shorten the operating time and avoid damage to the small branch, magnifying loupes are recommended as a precautionary mea- sure during dissection. In the medial thigh flap, after splitting of the sheath, the superficial femoral
artery itself serves as a good guide for tracing the vessels, but in the lateral thigh flap, one usually has to wander blindly among bulky fatty tissue looking for the branch and hence the chance of damaging it is accordingly much greater.
1. Baek SM (1983) Two new cutaneous free flaps: the medial and lateral thigh flaps. Plast Reconstr Surg 71:354
2. Guan WX, Qian YL, Chen KX, Xu LG (1986) Free medial thigh flap in treatment of advanced burn cases. Chin Med J 99:187