記住我
ORIGINAL ARTICLE
Year : 2022 | Volume
: 30
| Issue : 4 | Page : 91-95
Freestyle anterolateral thigh flap and perforator variations
Ersin Gur
Department of Plastic Reconstructive and Aesthetic Surgery, Ege University Faculty of Medicine, Izmir, Turkey
Correspondence Address:
Dr. Ersin Gur
Ege Üniversitesi Tip Fakültesi, Plastik Rekonstrüktif Ve Estetik Cerrahi Ad, Kazim Dirik Mah. Universite Cad. No: 9, Bornova, Izmir
Turkey
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/tjps.tjps_27_22
Introduction: Anterolateral thigh (ALT) flap has become an increasingly popular reconstructive option, especially for head-and-neck and extremity defects. In addition to the many advantages of the ALT flap, there are also some disadvantages such as individual variations in the number and location of cutaneous perforators. Doppler ultrasonography (USG) is one of the most frequently used methods to overcome variations in perforator anatomy. However, the Doppler device may obtain false results so some clinics use the “freestyle” harvesting technique for ALT flap. The aim of the study is to examine experience with freestyle ALT flap harvesting and to evaluate the perforator variations. Materials and Methods: Between 2018 and 2021, 59 ALT flaps were harvested by the same microsurgical team for head-and-neck reconstructions. Of 59 patients, 23 were female and 36 were male. Cases were performed without using preoperative or peroperative imaging techniques. Results: In 2 (3%) of 59 patients, different septocutaneous flap options were used because suitable perforators could not be found in both thigh regions. For 57 ALT flaps, the rate of descending branch of lateral circumflex femoral artery (LCFA) perforators was 73%, transverse/ascending branch was 17%, aberrant perforators other than classical branches of LCFA was 7%, and the perforator from medial circumflex femoral artery was 1%. Partial necrosis due to perfusion problem was experienced in one flap and total necrosis was in two flaps. Conclusion: The advantages of the freestyle technique, such as allowing the evaluation of all perforators and designing flaps according to the appropriate perforator, provide great flexibility and convenience to the surgeon. With this, surgical problems caused by inaccurate results obtained by devices such as Doppler USG are excluded.
Keywords: Anterolateral thigh, free flap, freestyle, perforator
The anterolateral thigh (ALT) flap has become an increasingly popular reconstructive option, especially for head-and-neck and extremity defects.[1],[2],[3] Although Song et al. stated the thigh flap's advantages as having a long and large-caliber vascular pedicle, a wide and flexible skin island, and minimal morbidity in the donor site,[1],[4],[5],[6],[7],[8] it also has some limitations. The major disadvantage which can affect flap success is individual variations in the number and location of cutaneous perforators. Thus, flap dissection is generally more complex than standard flaps such as the radial forearm flap or the latissimus dorsi muscle flap.[4],[8]
Advances in microsurgery have led to a better understanding of perforator flaps resulting in modification of the dissection technique over time. The localization of the appropriate perforator of the ALT flap is the subject of many studies.[3],[7],[8],[9],[10],[11],[12],[13] Xu et al.[14] detected 92% of the cutaneous perforators via Doppler ultrasonography (USG) in a circle of 3-cm radius which centered at the midpoint of a line between the anterior superior iliac spine (ASIS) and the superolateral border of the patella.
Many imaging methods such as conventional USG, Doppler USG, and computerized tomography (CT) are used in preoperative flap design to overcome variations in perforator anatomy.[2],[10],[11],[12] The cost-effectiveness and use of contrast material which makes it difficult to use in patients with comorbidities are disadvantages of CT.[11] In addition, since Doppler USG can cause time-consuming and inaccurate results, many surgeons have turned to the “freestyle” technique, in which postincision perforators are searched and dissected up to the main pedicle, if available, without using preoperative imaging.[10],[15],[16],[17]
The study aims to describe the freestyle ALT flap harvesting technique experience of our practice retrospectively and examination of the perforator variations of the ALT flap.
Materials and MethodsBetween 2018 and 2021, ALT flaps were used in head-and-neck reconstructions for 59 patients (23 females and 36 males) due to various etiologies in our clinic. All cases were performed by two simultaneous head-and-neck and microsurgery teams. All flap harvesting and anastomoses were performed by the same surgical team.
Surgical technique
After a straight line was drawn from the ASIS to the lateral border of the patella, the midpoint of the line was marked. Half of the width of the defect to be reconstructed was calculated. This length was extended from the midpoint of the line to the medial, so the medial upper border was determined. The 10-cm initial incision was made approximately 2 cm medial and parallel to this border [Figure 1]. The rectus femoris muscle fascia was passed and sharp–blunt dissection was made under the deep fascia from medial to lateral. Contrary to classical ALT harvesting, possible perforators coming from inside the rectus femoris muscle (Group III) were not sacrificed until perforators expected to originate from the intermuscular septum between the rectus femoris and vastus lateralis muscles were seen. In the absence of a suitable perforator coming from the intermuscular septum, the incision was extended proximally and distally. When proper perforators were identified such as perforators that pierced the tensor fascia lata, these perforators were used. If no suitable perforator was found, Group III perforators were dissected and dissection continued until the appropriate diameter was reached for the anastomoses. As a last option, the incision was extended more medially and another perforator was searched as freestyle in the medial region [Figure 1].
Figure 1: (a) Freestyle harvesting of the ALT flap. The midpoint of a straight line between the ASIS and the lateral patellar area is drawn (black line). The midpoint of the width of the defect is centered to predetermined midpoint (green line in the medial is accepted as the border, the width of the defect is accepted as between two green lines). The initial incision is made at a length of 10 cm, approximately 2 cm medial to medial green line (red line). (b) During dissection through the deep fascia, Group III perforators (green) are preserved until Group I and II perforators are seen. If Group I and II perforators are not found, the dissection is continued with the previously found Group III perforators. In the absence of a suitable perforator, the dissection is advanced medially for Group IV perforators. ALT: Anterolateral thigh, ASIS: Anterior superior iliac spineAs the incision was extended more proximal, distal, or medial, the flap size to be used was re-designed according to the position of the suitable perforator. After the initial incision of the flap was made with the help of a scalpel, the deep fascia was descended with the help of electrocautery and all subsequent dissection was performed using sharp–blunt dissection scissors. All flap harvestings were performed without the use of an imaging instrument such as a Doppler device preoperatively. The dissection steps for all flaps were performed without the use of devices such as magnifying glasses. The preparation phase of the vessels for anastomosis and the anastomosis phase were performed via microscope.
ResultsDifferent septocutaneous flap options were used in 2 (3%) of 59 patients since no suitable perforator could be found in both thigh regions. Perforators were suitable in 57 patients including descending branch of lateral circumflex femoral artery (LCFA) in 42 flaps (73%), transverse/ascending branch in 10 flaps (17%), aberrant branches other than classical branches of LCFA in 4 flaps (7%) and 1 branch of medial circumflex femoral artery (1%). The perforator anatomy and approximate percentages are shown in [Figure 2]. Partial necrosis due to perfusion problem occurred in one flap and total necrosis occurred in two flaps [Table 1].
Figure 2: Perforators of anterolateral thigh flap and their approximate rates. Septocutaneous/musculocutaneous of descending branch of LCFA group (I), transverse/ascending branch of LCFA group (II), aberrant branch from the body of LCFA which comes to skin from the rectus femoris muscle group (III), branch from MCFA group (IV). LCFA: Lateral circumflex femoral artery, MCFA: Medial circumflex femoral artery
Table 1: Perforator distributions and flap survival of freestyle harvested anterolateral thigh flaps Discussion The ALT flap is widely used in reconstructive surgery as it has low donor site morbidity compared to many alternatives. Although variations in vascular anatomy have been described, the use of ALT flap is frequently defined with successful results. However, the perforators of the LCFA system can show variations in localization, caliber, and the intramuscular and subcutaneous course between different patients and between both thighs in the same patient.[4],[9]
Song et al.[7] reported that the descending branch of the LCFA gave a septocutaneous perforator in the proximal third of the lateral thigh and that perforator passed from the intermuscular septum between the rectus femoris and vastus lateralis muscles to the fascia lata and adjacent skin area. They reported that accessory muscle perforators were frequently present proximal or distal to the main septocutaneous perforators, but the main perforator was fixed in terms of diameter, vascular anatomy, and position.
Zhou et al.,[18] on the other hand, defined that the exit point of the cutaneous perforator from the intermuscular septum or vastus lateralis was generally 2 cm lateral and 2 cm inferior to the midpoint of the line connecting the ASIS and the superolateral border of the patella. Kimata et al.[1] confirmed in their series of 74 cases that cutaneous perforators were concentrated near the midpoint of the line connecting the superolateral border of the ASIS and patella. In 2004, Yu[19] introduced the 'A,B,C'system to clarify the distribution and location of cutaneous perforators. In Yu's study, 1–3 cutaneous perforators of the ALT flap were identified at specific locations and were named proximal to distal perforators as A, B, and C. The perforator B was located near the midpoint of the line connecting the ASIS and the superolateral edge of the patella. Perforators A and C were located 5 cm proximal and distal to perforator B, respectively.
Freestyle free flap harvesting is not a new technique. This technique is used by different clinics because of the false results that can be seen as a result of the use of Doppler USG.[10],[15],[16],[17] Rozen et al.[10] defined the order of suitable perforators searched and selected with freestyle for the ALT flap as septocutaneous perforators, musculocutaneous perforators, anteromedial thigh perforators, and the perforators of the tensor fascia lata (ascending or transverse branch of the LCFA). In the absence of a suitable perforator, the contralateral thigh flap was selected as the donor site.
In our clinical series, suitable perforators in most cases were septocutaneous or musculocutaneous perforators (73%). However, in the presence of a suitable perforator that could not be found in this region, the ascending/transverse branch, especially more proximal, was chosen as the appropriate perforator.
The transverse branch was found to be thicker than the branches in the middle segment. For this reason, we think that it is advantageous, especially in the harvesting of large diameter ALT flaps over a single perforator. However, due to its proximity to the main pedicle, care should be taken in cases where the pedicle is short. Pedicle length gains importance, especially in patients who have a previous neck dissection and/or radiotherapy history, and therefore do not have many options as a suitable recipient for the neck. In these cases, it is appropriate to use the transverse perforator by positioning it to the more lateral part of the flap, rather than the midpoint of the flap to be used. In this way, it is possible to provide partial extension by positioning the perforator more laterally [Figure 3]. In using this method, it is important to correctly evaluate the size of the flap and the thickness of the perforator to prevent partial necrosis. Since the transverse branches are relatively thicker and stronger, there is often no problem in our experience.
Figure 3: Group II perforators, if the transverse branch is selected, the pedicle may be short due to the proximity of the perforator to the source artery. The perforator can be located to the midpoint of the flap (a) or laterally (b). By positioning the relatively thicker transverse branch laterally instead of the midpoint of the flap, a sufficient length can be gainedIn 4 of 57 patients [Figure 1] and [Figure 2], another branch (Group III) originated from the main body of LCFA and came from the rectus femoris muscle. The choice of this branch should be preferred when suitable perforators are not available as Groups I and II. Due to it continues almost along the entire line without thickening, the dissection of this perforator is more difficult according to our experience. In oromandibular defects, when the pedicle is to be transferred from the mouth to the neck region by opening a tunnel, care should be taken due to the thinness of the vessel. We think that small diameter vessels are more vulnerable to complications that may develop after the operation, such as squeezing due to edema or hematoma between adjacent anatomical structures. This branch emerges from the rectus femoris muscle before reaching the intermuscular septum. Therefore, it should not be sacrificed without being sure that classical perforators exist.
In cases where none of the options were suitably mentioned above, the dissection was extended medially as freestyle in one patient in our series [[Figure 1], Group IV]. In the selection of this group of perforators, it is important to continue the dissection until the appropriate diameter is reached after the recipient artery and vein are determined, to overcome the problems that may be encountered due to the diameter difference during anastomosis.
Previously, it was in our routine practice to search for perforators using Doppler USG before the operation and the flap design, so skin incision was performed according to the Doppler result. However, in some cases, we had to re-design the flap due to false result of Doppler. It was difficult because the initial skin incision was depended on the false location of the perforator. We think that freestyle flap harvesting is more advantageous and reliable. With the technique, the perforators are not sacrificed beforehand and evaluation of all perforator options is possible at the same time, so it provides making the appropriate perforator choice and flap designing [Figure 4].
Figure 4: An illustration of inaccurate result of Doppler USG, flap design, and the advantage of freestyle technique. The perforator (green point) is listened by Doppler and the flap design (green ellipse) is made for the defect with reference to this perforator. An illustration of a more suitable perforator (red point) whose exact location cannot be detected by Doppler and the incision which is made for freestyle flap harvesting (red line). In freestyle flap harvesting, the incision is designed in such a way that all perforators can be evaluated without focusing on any perforator location beforehand. The incision can be continued up or down as needed, or the dissection can be directed medially. USG: UltrasonographyThe only disadvantage of the freestyle technique is to start the incision as if a flap is slightly larger than needed. However, while it is possible to reduce a large harvested flap afterward, we believe that it is more difficult to overcome the problems encountered during the operation mentioned above. Moreover, especially in cases when two teams work simultaneously, for example, head-and-neck reconstruction, the defect due to tumor excision may be larger than planned before the operation. Hence, especially in two team approaches that performed tumor excision and flap harvesting at the same time, slightly larger flap harvesting is effective for overcoming the size problems that may occur later.
ConclusionThanks to its many advantages, the ALT flap has taken its place as the first choice for many clinics in soft-tissue reconstructions. Perforator variations can be seen in every perforator flap, as well as in the ALT flap. The advantages of the freestyle technique, such as allowing the evaluation of all perforators and designing flaps according to the appropriate perforator, provide great flexibility and convenience to the surgeon. With this, surgical problems caused by inaccurate results of devices such as Doppler are ruled out. Although the technique requires surgical experience, it can be successfully applied in clinics where the ALT flap is routinely used and where this flap is familiar.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
留言 (0)