Modification of the Pedicled Anterolateral Thigh Myocutaneous Flap for the Reconstruction of Ischial Pressure Ulcers: A Retrospective Case Study of 21 Patients

Introduction. Ischial pressure ulcers are considered the most difficult type of pressure ulcers (PUs) to treat. Objective. The authors report the use of a pedicled anterolateral thigh (pALT) myocutaneous flap as an alternative for covering an ischial PU. Materials and Methods. The authors retrospectively collected the data of 21 patients with an indurated recurrent ischial ulcer or a fresh ischial ulcer. A pALT myocutaneous flap was harvested without intramuscular dissection and skeletonization of the perforators for the ischial defect reconstruction. Two modified flap-insetting techniques, an open-route method and a subcutaneous tunnel method, were used for the ischial defect reconstruction. The open-route flap-insetting was used for a recurrent ulcer status after other surgical procedures, and the subcutaneous tunnel method was used for fresh ulcers. Results. The mean follow-up period was 10 months (range, 4–14 months). During the postoperative follow-up, all open-route reconstructions resulted in flap take; however, poor healing with seroma was noted in 2 patients who had undergone pALT reconstruction with subcutaneous tunneling after other previous surgical reconstructions. Conclusions. In the authors’ experience, because of constant blood supply, sufficient bulk, easy elevation, longer pedicle for the arc of rotation, primary closure of the donor site without morbidity, and a non-weightbearing flap donor site, the pALT myocutaneous flap for ischial ulcer reconstruction can serve as a primary treatment and secondary salvage.

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Many different types of flaps are available for treating ischial pressure ulcers (PUs), including primary wound closure, gluteus maximus myocutaneous flap, V-Y hamstring flap, and inferior gluteal artery perforator flap. However, recurrent ischial PUs are a concern for surgeons because of the poor outcomes associated with these typical surgical methods. Although more commonly used as a free flap, the anterolateral thigh flap can be harvested as a pedicled flap to cover tissue defects in the groin, lower abdomen, perineum, trochanter, and knee.^1,2 Although the versatile application of pedicled anterolateral thigh (pALT) flaps for reconstruction surgery is reliable, perforator dissection is tedious and time-consuming. Subsequently, Wang et al³ modified and simplified the pALT perforator flap into a myocutaneous flap without skeletonization of the perforators to cover trochanteric PUs.Based on previous experience, the authors present a modified method of using the pALT myocutaneous flap for the reconstruction of ischial PUs.

The records of 21 patients treated with pALT myocutaneous flaps harvested for the reconstruction of recurrent ischial PUs from 2008 to 2015 in Tri-Service General Hospital (Taipei City, Taiwan) were reviewed. The pALT myocutaneous flaps were applied for the reconstruction of grade IV ischial pressure ulcers without infection. The flaps ranged in size from 24 cm² to 108 cm². With respect to the wound condition, only stage IV PUs that showed resolution of the infection after adequate surgical debridement were selected. Inclusion criteria consisted of a stage IV PU and exclusion criteria consisted of patients more than 80 years of age. Detailed patient information is provided in the Table.

Surgical technique
During the surgery, all flaps were raised by the standard dissection technique. The patient was placed in 2 positions during the operation. In the harvesting position, the patient was in the supine position (Figure 1A); for the insetting position, the patient was placed in a lateral decubitus position with the buttock ipsilateral to the ischial ulcer facing upward (Figure 1B). In the authors’ experience, it is easy to harvest the flap in the supine position whereas the flap is inset and the donor site is closed simultaneously and efficiently in the lateral decubitus position.

At first, surgical debridement was performed adequately to preserve the healthy tissue. In the harvesting position, a line was drawn between the anterosuperior iliac spine and the superolateral aspect of the patella; this line lied between the vastus lateralis muscle and rectus femoris muscle. The midpoint of this line was identified and a 6-cm circle was outlined at the midpoint to identify reliable vascular perforators (usually located within the circle).⁴ The flap size was designed based on the ulcer size, and the flap location was chosen near the aforementioned circle. For an adequate rotational arc, the pedicle length (L1) from the origin of the descending branch of the lateral circumflex femoral artery (LCFA) to the pALT myocutaneous flap must be longer than the distance (L2) between the origin of the descending branch and the ischial ulcer (Figure 2). Besides, because the flap harvested was of myocutaneous type, it was not necessary to detect the cutaneous perforators by Doppler ultrasonography preoperatively. After the subfascial dissection proceeded laterally towards the intermuscular space between the rectus femoris and vastus lateralis muscles, the pedicle (the descending branch of the LCFA) was identified. The route of the perforator (intramuscular or septocutaneous) was not a concern, because intramuscular dissection and skeletonization of the perforators were not necessary. Therefore, electrocautery is a good tool for flap harvesting. The flap was designed as a myocutaneous flap to increase its volume for the affected ischial ulcers. The desired size of the flap was marked, depending on the extent of the ischial defect, with the upper third of the flap centered over the line between the vastus lateralis and rectus femoris muscles. It is important to avoid designing a flap with a central perforator as this might result in a myocutaneous flap containing less vastus lateralis muscle on the medial side. The pALT myocutaneous flap was rotated laterally to be inset into the ischial defect via a subcutaneous tunnel in the lateral thigh or through a wide-open incision tract to the ischial ulcer. After adequate hemostasis, the donor site was closed primarily.

Two modified flap-insetting techniques, an open-route method and a subcutaneous tunnel method, without intramuscular dissection and skeletonization of the perforators were used for the ischial defect reconstruction. The open-route flap-insetting technique was used for a recurrent ulcer with severe subcutaneous fibrosis status after other surgical procedures, whereas the subcutaneous tunnel method was used for acute ulcers (Figure 3). As compared with the subcutaneous tunnel method, it is much easier to inset the flap and achieve adequate fibrotic tissue excision simultaneously through open-route flap-insetting.

From 2008 to 2015, 21 pALT flaps were applied to the patients with ischial PUs (Table). The pALT myocutaneous flaps were harvested from the vastus lateralis muscle and without intramuscular dissection or skeletonization of the perforators. The flaps ranged from 24 cm² to 108 cm² in size, and the pedicles were designed to reach the ischial defects without tension. In the reviewed cases, 10 pALT flaps were inset via the open-route method because of severe subcutaneous fibrosis caused by recurrent surgeries and the other 11 flaps were inset using subcutaneous tunnels for better aesthetic outcome. All open-route reconstructions of ischial ulcers resulted in good aesthetic outcomes; however, poor healing of the flap edge with seroma was noted in 2 patients who had undergone pALT reconstruction with subcutaneous tunneling after other previous surgical reconstructions. All donor site wounds were closed primarily without infection, wound dehiscence, delayed healing, hematoma, or seroma.

Case reports
Case 1. A 65-year-old man had been experiencing a lumbar spinal injury with paraplegia resulting from trauma for more than 20 years. Prior to the surgery, the initial dimensions of the ischial ulcer were about 5 cm x 5 cm, and it was located deep in the muscular fascia (Figure 4A). A pALT myocutaneous flap procedure was performed for the ischial ulcer through the subcutaneous tunneling method. The length of the pedicle was about 12 cm. The donor site was closed primarily without any morbidity (Figure 4B). During the 4-month postoperative outpatient follow-up, it was observed that the ischial PU had healed without wound dehiscence (Figure 4C).

Case 9. A 43-year-old woman, with a medical history of systemic lupus erythematosus with T3–4 spondylomyelitis and paraplegia for 28 years, presented with a recurrent ischial ulcer measuring 8 cm x 6 cm (Figure 5A). She had undergone flap surgeries, including primary wound closure and a gluteus maximus myocutaneous flap, in the previous 2 years. The pALT myocutaneous flap measured 18 cm x 6 cm and was inset into the defect via the open-route method (Figure 5B) after total removal of the fibrotic scar tissue. At the 1-year follow-up, it was observed that the wound had healed without recurrence (Figure 5C).

Case 20. A 59-year-old man, who had a 14-year history of paraplegia prior to pALT flap placement, presented with an ischial ulcer measuring 3 cm x 3 cm. During the last decade, the patient had undergone local flap reconstruction of the ischial ulcer 3 times due to recurrence and the last local flap reconstruction was performed 6 months prior. The wound was treated using a pALT myocutaneous flap, about 7 cm x 5 cm in size, with the subcutaneous tunneling method. However, poor healing of the flap edge with persistent seroma formation was noted at the 12-month follow-up after flap surgery.

Over the past few decades, surgical reconstruction has been a mainstay of treatment for PUs.⁵  In addition, recent progress in the development of versatile surgical methods, anesthesiology, and intensive care units has enabled more surgeons to treat patients with PUs.^6-8 Surgical reconstruction protects the patient against infection, protein loss, and less daily skilled wound care, resulting in reduced morbidity, mortality, and economic burden.^9,10 Even in patients with multiple PUs, earlier surgical treatment can provide a shorter recovery period, shorter hospitalization duration, and cost effectiveness without a significant increase in the complication rate.¹¹

It is important to treat chronic recurrent ischial PUs in paraplegics and geriatric patients because of their significant morbidities. Compared with sacral and trochanteric ulcers, ischial ulcers are the most difficult to treat and have high recurrence rates (> 50%).¹² Previously, surgeons treated a fresh ischial ulcer with first-line conventional flaps, such as gluteus maximus myocutaneous flap, inferior gluteal thigh flap, and V-Y hamstring flap.¹² However, once an ischial ulcer recurs after flap coverage with one of those techniques, the choice of reconstruction is limited; therefore, the use of the pALT myocutaneous flap should be considered.^13-15 The free anterolateral thigh flap has been used extensively in the reconstruction of head and neck defects since its introduction by Song et al¹⁶ in 1984. In 1989, Koshima et al¹⁷ first mentioned the use of an island flap of the anterolateral thigh in repairing neighboring defects. In 1998, Kimata et al¹⁸ studied the anatomic variations and technical problems of the anterolateral thigh flap and used the term pedicled anterolateral thigh flap for the first time. The advantages of an island pALT myocutaneous flap include constant blood supply, sufficient bulk, easy elevation, longer pedicle for the arc of rotation, primary closure of the donor site without morbidity,^13-15 and non-weightbearing flap donor site. A long vascular pedicle and lack of restriction to the arc of rotation are important for the successful transposition of a flap for reconstructing the ischial region. In addition, the pALT myocutaneous flap provides sufficient bulk to obliterate the dead space caused by adequate debridement and offers a good cosmetic effect due to its superior vascularity and padding as compared with the conventional flaps. In addition, myocutaneous flaps are effective in treating infected wounds.²

The present study noted that the donor sites of the conventional flap and pALT myocutaneous flap were the gluteal region and the anterolateral thigh, respectively. As compared with the gluteal region, the anterolateral thigh bears less pressure in both sitting and prone positions. In other words, the donor site of the pALT myocutaneous flap is non-weightbearing. The previously mentioned advantage decreases the morbidity of the donor site. Besides, variations occur in the vascular anatomy, including the musculocutaneous or septocutaneous perforators. Most of the perforators, ranging from 74% to 90% of the flaps in the literature, are musculocutaneous.^1,19,20 Intramuscular perforator dissection and skeletonization of a musculocutaneous perforator are time-consuming; however, in the authors’ experience, pALT myocutaneous flaps are harvested quickly with the vastus lateralis muscle and without intramuscular dissection or skeletonization of the perforators. Although the aforementioned simplified technique makes the reconstruction quicker as compared with that with conventional flap reconstruction, it still takes more time to complete the pALT myocutaneous flap reconstruction; this is the main disadvantage of the island pALT myocutaneous flap. In addition, the flap is rotated laterally to be inset into the ischial defect via a subcutaneous tunnel in the lateral thigh or through an open-route incision tract to the ischial ulcer.

In case 20 presented here, the patient with recurrent ischial ulcer status after 3 local flap reconstructions ultimately was treated with the pALT myocutaneous flap via subcutaneous tunneling, but he demonstrated poor healing of the flap edge, persistent seroma observed at the 12-month follow-up post flap surgery, and fibrotic tissue formation noted in the subsequent exploratory surgery. The recurrent ischial ulcer treated with more than 1 surgical procedure might have led to indurative fibrosis over the subcutaneous layer of the gluteal region, and the subcutaneous tunneling procedure over this region might have caused the dead space and seroma formation. Therefore, the pALT myocutaneous flap with open-route flap-insetting has been suggested for the treatment of recurrent ischial ulcers following other surgical procedures because adequate fibrotic tissue excision can be performed during the open-route flap-insetting procedure to avoid possible subsequent seroma formation.

Consequently, the authors modified the flap-insetting technique to employ the open-route method for recurrent ulcers previously treated with other surgical procedures and the subcutaneous tunneling method for fresh ulcers (Figure 3). The flap repair is associated with decreased complications. Pressure ulcer reconstruction requires careful patient selection and surgical technique to decrease the risks.⁹

In the reconstruction ladder, the first-line methods to treat ischial ulcers are conventional flaps. However, in the authors’ experience, as compared with conventional flaps, pALT myocutaneous flaps are more advantageous in resisting weightbearing in paraplegics and geriatric patients. Therefore, the authors consider that a pALT myocutaneous flap for ischial ulcer reconstruction can serve as a primary treatment as well as play a role in the secondary salvage.

Compared with conventional flaps, the pALT myocutaneous flap reconstruction takes more time to complete. With the inclusion criteria consisting of a stage IV PU and exclusion criteria of a patient aged more than 80 years, elderly patients with poor physical status and not suitable for anesthesia were deemed inappropriate for this study.

The advantages of the island pALT myocutaneous flaps include constant blood supply, sufficient bulk, easy elevation, longer pedicle for the arc of rotation, primary closure of the donor site without morbidity, and a non-weightbearing flap donor site. The pALT myocutaneous flap is harvested with the vastus lateralis muscle and without intramuscular dissection and skeletonization of the perforators. For flap insetting, the open-route method is recommended for recurrent ulcers after other surgical procedures, whereas fresh ulcers should use the subcutaneous tunneling method for insetting. The pALT myocutaneous flap for ischial ulcer reconstruction can play a role not only in the secondary salvage but also as a primary treatment.

Authors: Chi-Yu Wang, MD^1,2; Chien-Ju Wu, MD¹; Yu-Jen Shih, MD¹; Tzi-Shiang Chu, MD¹; Hung-Hui Liu, MD¹; Chun-Yu Chen, MD¹; Kuo-Feng Hsu, MD¹; Shyi-Gen Chen, MD, MPH, Professor¹; and Yuan-Sheng Tzeng, MD¹

Affiliations: ¹Division of Plastic Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; and ²Division of Plastic Surgery, Department of Surgery, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan

Correspondence: Yuan-Sheng Tzeng, MD, Plastic and Reconstructive Surgery, Tri-Service General Hospital, National Defense Medical Center, No. 325, Cheng-Kung Rd, Sec 2, Neihu 114, Taipei, Taiwan; m6246kimo@yahoo.com.tw

Disclosure: The authors disclose no financial or other conflicts of interest.