Pre-expanded Thoracodorsal Artery Perforator Flap

The size of the thoracodorsal artery perforator (TDAP) flap or pedicle, in general, may be found to be inadequate. Pre-expansion of the flap before harvest can be a solution to increase the size of the TDAP flap in such instances. The pre-expanded TDAP flap can be used to reconstruct large-sized defects with the advantage of primary closure of the donor site. This article presents details on the surgical technique and provides discussion of the authors’ experiences.

Key points

  • Mark the perforator arteries and anterior border of the latissimus dorsi muscle before surgery with the patient in the lateral decubitus position.

  • Perform subfascial dissection to find the perforator.

  • Place the tissue expander precisely according to the pedicle and its vascular territory to avoid complications.

  • Perform the dissection meticulously in the second operation based on the high risk of injuring the pedicle in scar tissue.

  • Do not skeletonize the pedicle in both stages and dissect the pedicle with a small amount of fibrotic and soft tissue around in case of necessity.

Introduction

The thoracodorsal artery perforator (TDAP) flap was first described in 1995 as “latissimus dorsi musculocutaneous flap without muscle,” and is based on perforators from the thoracodorsal artery. Therefore, its proper name is the thoracodorsal artery perforator flap. It has been used for reconstruction of head and neck, extremities, axillary region, chest wall, and the back. However, the disadvantages of the flap are perforator anatomy variations, difficulties in preoperative localization of a reliable perforator, and intramuscular dissection. Furthermore, if the TDAP flap is large, necrosis at the distal site of the flap is possible. Pre-expansion of the flap provides a delay phenomenon and probably increases the flap survival area.

The use of the TDAP flap has increased recently because of its advantages. The factors that affect the widespread use of the flap are summarized as follows: basic and reliable anatomy, the ability to be thinned without compromising blood supply, the possibility of obtaining a long pedicle, the pliability of the flap, and the lack of significant donor site morbidity. However, in a number of situations, the size of the flap or pedicle can be found to be inadequate. To provide a solution in these cases, pre-expansion of the TDAP flap may be used to increase the size of the flap.

A pre-expanded TDAP flap can be especially useful in releasing axillary burn contractures that require large amounts of skin flap. Another important advantage of the technique is that it allows primary closure of the donor site.

Introduction

The thoracodorsal artery perforator (TDAP) flap was first described in 1995 as “latissimus dorsi musculocutaneous flap without muscle,” and is based on perforators from the thoracodorsal artery. Therefore, its proper name is the thoracodorsal artery perforator flap. It has been used for reconstruction of head and neck, extremities, axillary region, chest wall, and the back. However, the disadvantages of the flap are perforator anatomy variations, difficulties in preoperative localization of a reliable perforator, and intramuscular dissection. Furthermore, if the TDAP flap is large, necrosis at the distal site of the flap is possible. Pre-expansion of the flap provides a delay phenomenon and probably increases the flap survival area.

The use of the TDAP flap has increased recently because of its advantages. The factors that affect the widespread use of the flap are summarized as follows: basic and reliable anatomy, the ability to be thinned without compromising blood supply, the possibility of obtaining a long pedicle, the pliability of the flap, and the lack of significant donor site morbidity. However, in a number of situations, the size of the flap or pedicle can be found to be inadequate. To provide a solution in these cases, pre-expansion of the TDAP flap may be used to increase the size of the flap.

A pre-expanded TDAP flap can be especially useful in releasing axillary burn contractures that require large amounts of skin flap. Another important advantage of the technique is that it allows primary closure of the donor site.

Preoperative planning and preparation

Before surgery, the perforator arteries are marked using a handheld Doppler ultrasound apparatus (Huntleigh dopplex, Cardiff, United Kingdom) with the patient in the lateral decubitus position. If the surgeon adheres to the previously defined surgical determinants, success is very likely while planning and harvesting the flap. A line indicating the anterior border of the latissimus dorsi (LD) muscle is drawn. The first perforator usually emerges from a point 8 to 10 cm inferior to the posterior axillary fold and 1 to 2 cm posterior to the anterior border of the LD muscle. Another landmark is 4 cm (range, 3–6 cm) below the tip of the scapula and 2.5 cm posterior to the anterior border of the LD muscle ( Fig. 1 ). The thoracodorsal artery bifurcates at that point to medial (or horizontal) branch and lateral (or descending) branch. Both branches of the thoracodorsal artery are under the surface of the LD muscle throughout the course.

Fig. 1
Schematic diagram of the preoperative planning. a, artery; LD, latissimus dorsi muscle; m, muscle; S, scapula; X, first thoracodorsal artery perforator. Blue double arrow is approximately 8 to 10 cm inferior to the posterior axillary fold, green double arrow is approximately 1 to 2 cm and shows the distance posterior to the anterior border of the LD muscle, black double arrow is 4 cm (range, 3–6 cm) diameter below the tip of scapula, and yellow circle shows the possible bifurcation location of thoracodorsal artery.

Patient positioning and surgical technique

Once anesthesia is used, the patient should be placed in the lateral decubitus position with the arm abducted 90° over. In this position, an incision is made in the area corresponding to the anterior border of the LD muscle. After revealing the anterior border of the LD muscle, a subfascial dissection is performed to find the perforator and create a pocket for the tissue expander ( Fig. 2 A ). Exposing the pedicle completely at this stage of surgery should be avoided. However, many perform suprafascial dissection. Both surgical plans can be executed; it is up to the surgeon’s preference. Afterward, a tissue expander is placed ( Fig. 2 B) and 2 weeks after surgery, serial expansions start.

Fig. 2
( A ) Intraoperative view of the prepared pocket for the tissue expander and the pedicle. White arrows show the pedicle (the inset at the right top shows the zoom-in view of the pedicle). ( B ) After the tissue expander was placed in the pocket.

A second operation is carried out a minimum of 4 weeks after completion of the expansion. In the second stage, dissection should begin at the anterior side of the flap using the previous incision. Subfascial dissection is performed to find the perforator initially. At this stage, one needs to be very careful because the perforator can be injured easily based on the scar tissue. It is suggested to not skeletonize the perforator as it should be dissected with a little bulk around it. Next, intramuscular dissection toward the descending branch and the thoracodorsal artery is performed.

The pre-expanded TDAP flap is harvested with the capsule following pedicle dissection. The dissection should be performed precisely because of the adherence of the expander capsule to the perforator ( Fig. 3 ). The TDAP flap donor site can be sutured primarily.

Nov 21, 2017 | Posted by in Dental Materials | Comments Off on Pre-expanded Thoracodorsal Artery Perforator Flap
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