One-Stage Reconstruction of Large Midline Abdominal Wall Defects Using a Composite Free Anterolateral Thigh Flap With Vascularized Fascia Lata

Abstract

Objective:

Large midline abdominal wall defects are continuously a challenge for reconstructive surgeons. Adequate skin coverage and fascia repair of the abdominal wall is necessary for achieving acceptable results. The purpose of this paper is to present a new approach to abdominal wall reconstruction using a free vascularized composite anterolateral thigh (ALT) flap with fascia lata.

Methods:

Seven patients with large full-thickness abdominal wall defects were successfully reconstructed by means of a composite ALT flap combined with vascularized fascia lata. The size of the skin islands ranged from 20 to 32 cm in length and 10 to 22 cm in width, and the vascularized fascia lata sheath measured 14 to 28 cm and 8 to 18 cm, respectively. Functional outcome of the abdominal wall strength and donor thigh morbidity were investigated by using a Cybex kinetic dynamometer.

Results:

All flaps survived. No postoperative ventral hernia occurred except for one mild inguinal incision hernia. Subjectively there were no significant donor site problems. Objective assessment was performed in 4 patients 2 years postoperatively. In the reconstructed abdomen, isokinetic concentric and eccentric measurements of extension/flexion ratios of the abdominal wall strength showed no apparent decrease compared with other references. Functional evaluation of quadriceps femoris muscle contraction forces after free ALT composite flap harvest showed an averaged deficit of 30% as compared with the contralateral legs. However, no difficulties in daily ambulating were reported by the patients.

Conclusion:

The free composite ALT myocutaneous flap with vascularized fascia lata provides an alternative option for a stable repair in complex abdominal wall defects.

Seven patients with large full-thickness abdominal wall defects were successfully reconstructed by means of a composite anterolateral thigh flap combined with vascularized fascia lata. The patients reported no difficulties in daily ambulating. The donor thighs morbidity is minimal objectively after investigation by kinetic dynamometer machine.

Large supraumbilical full-thickness defects of the abdominal wall present a difficult reconstructive challenge.¹ They can occur after acute trauma, following resection of soft tissue tumors, or result from peritonitis.^1–4 Three major issues need to be addressed when reconstructing such defects that are not amenable to direct, primary closure: stable reconstruction of the fascial layer, adequate skin coverage, and restoration of the contour of the abdominal wall. Although small defects can be closed directly with local tissues or pedicled flaps, large abdominal wall defects (>40 cm²) frequently require a staged repair.^4–5 Using conventional methods, a temporary abdominal closure can be accomplished with a variety of synthetic coverings, followed by skin grafting directly onto visceral granulation tissue.^6–7 Subsequently, the resulting abdominal wall defect is reconstructed by fascial closure, prosthetic reinforcement, tissue rotation, pedicled flaps, or free tissue transplantation.^8–10 However, such multiple stage reconstructions are time- and cost-consuming, and the results are usually not satisfying.4,11,12,13 Therefore, one-stage reconstruction with vascularized fascia has been proposed to overcome such disadvantages.^14–17

The anterolateral thigh (ALT) flap is used for reconstruction of various types of defects.^13,18–21 In a previous report, the ALT flap with vascularized fascia lata was successfully employed for reconstruction of composite Achilles tendon defects.¹⁶ The fascia lata receives sufficient blood supply via the prefascial and subfascial vascular plexus when attached to the ALT flap.^16,22 The excellent blood supply makes the composite ALT flap a valuable tool that resists infection and reduces recovery time, when used for reconstruction of complex abdominal wall defects. However, possible donor site morbidity needs to be considered. The vastus lateralis is the largest compartment of the quadriceps femoris muscle, which is the prime extensor of the knee.^19,23,24 Harvest or injury of this muscle might subsequently lead to weakness of the knee function.

This paper presents our approach to reconstruct a composite full-thickness abdominal wall defect by using a free composite ALT flap with vascularized fascia lata. Objective assessment of the strength of the reconstructed abdominal wall and of the donor thighs was performed using Cybex kinetic dynamometer machines.^25–28

MATERIALS AND METHODS

From August 1998 to December 2001, 7 free composite ALT flaps with vascularized fascia lata grafts were transplanted to reconstruct full-thickness abdominal wall defects with visceral organ exposure (Table 1). There were 4 male and 3 female patients, age ranged from 26 to 69 years (mean 54 ± 14.5). Three patients were treated for acute blunt abdominal trauma, 3 for abdominal defects after laparotomy following organ perforation with peritonitis, and 1 patient after wide excision of a malignant fibrous histiocytoma (MFH) with abdominal wall invasion. Six patients had been covered temporarily with Malex silicon sheets. They received secondary reconstruction when their conditions were stable. One patient was reconstructed directly after the mentioned tumor excision. The size of skin islands of the ALT flaps ranged from 20 to 32 cm in length and 10 to 22 cm in width. The attached vascularized fascia lata measured 18 to 28 cm in length and 8 to 14 cm in width.

TABLE 1. Summary of Patients With Large Midline Abdominal Wall Defects

Operative Technique

In supine position, a line is drawn between the anterior superior iliac spine and the midpoint of the lateral border of the patella on the donor thigh.^16,18,19 Preoperatively, the location of the main cutaneous perforators from the vascular pedicle to the skin is detected and marked with an ultrasound Doppler. Usually these perforator vessels are centered at the midpoint of the line mentioned above. A medial incision above the rectus femoris muscle is done and deepened down to the subfascial plane. The pedicle is identified in the intermuscular septum between the rectus femoris and vastus lateralis muscles. It can be supplied either by the descending branch or by the transverse branch of the lateral circumflex femoral vascular bundle. The dissection continues underneath the deep fascia of the vastus lateralis muscle to include the major cutaneous perforators. Then, the dissection is extended laterally to include the adjoining fascia lata. During flap elevation all fascia lata sheets showed good bleeding from its subfascial and prefascial vascular plexus.¹⁶ All ALT flaps are harvested as myocutaneous flaps that include a cuff of vastus lateralis muscle (75 to 140 cm³). Together with an adequate size of fascia lata, the flap is elevated as a composite flap, while the tensor fascia latae muscle is left in place. At the recipient site, the fascia lata sheet is used for reconstruction of the missing abdominal fascia-sheath structure. The fascia lata is fixed to the respective remnants of the abdominal sheath with 2–0 PDS (Johnson & Johnson) interrupted sutures. Microvascular anastomoses are done to the inferior epigastric vessels. The skin island of the flap is sutured to the abdominal skin. A protective abdominal elastic bandage splint is left in place for 12 weeks to prevent postoperative herniation. The donor sites can be closed directly when the width of the flap is smaller than 8 cm, or is covered with split thickness skin grafts, if larger than 8 cm in width.

Functional Evaluation

Functional assessment included possible abdominal herniation, range of motion of the donor thighs, and daily ambulating activity after 1 year follow-up. Cybex isokinetic communicator (Cybex dynamometer; Lumex, Inc., Rokonkoma, NY) objective evaluations of the abdominal wall strength between flexion and extension was done after at least 1 year follow-up time. Four patients could coordinate the examiner's orders to completely perform all of these examinations. Isokinetic dynamometer measurements of the concentric strength of abdominal flexion and extension were performed under standardized conditions in standing position, and compared with other references.^27,28 The peak torque (Newton-meter) of isokinetic concentric and eccentric contraction tests of the quadriceps femoris muscles was evaluated at an angular velocity of 60 degrees per second. Isometric power tests (Newton) of the quadriceps muscles were performed at 60 degrees flexion. Both, the donor and the opposite healthy thighs were tested.

RESULTS

All 7 free flaps survived. One partial superficial flap necrosis healed uneventfully after surgical debridement. No hernias occurred, except for 1 inguinal incisional hernia due to weakness of the external oblique fascia. Abdominal wound infections in 2 patients healed after open drainage and wound care without sequelae. There were not any pulmonary complications or impaired ventilatory pressure, or abdominal compartment syndrome^5,29 (eg, elevated bladder pressure and decreased urine output, decreased venous return in combination with hemodynamic instability) occurred due to use the elastic splint wrap bandage to prevent herniation in all cases. All donor sites at the thighs needed skin grafting except for one that could be closed directly. All donor thighs healed uneventfully. All patients could ambulate without any support during the follow-up time, which was at least one year.

The isokinetic concentric and eccentric measurements of extension/flexion ratios showed a mild decrease in the peak torque power of the trunk flexion (Table 2) compared with other references.^27,28 Functional evaluation of quadriceps femoris muscle contraction forces after free ALT composite flap revealed a 20% to 45% deficiency in the isometric power tests at 30 degrees flexion of the quadriceps femoris muscles between donor and healthy thighs. There was an 8% to 30% deficiency in the isokinetic concentric test of the quadriceps femoris muscles and a 10% to 52% deficiency in the isokinetic eccentric tests of the quadriceps femoris muscles between donor and healthy thighs as shown in Table 3.

TABLE 2. Functional Assessment Between Flexion and Extension of the Trunk

TABLE 3. Functional Assessment of the Quadriceps Femoris Muscle Between Donor and Opposite Healthy Thighs

Case Reports

Case 1

A 64-year-old man presented a 20×10–cm, full-thickness abdominal wall defect after laparotomy due to hallow organ perforation and subsequent infection (Fig. 1A). A 22×10–cm free ALT flap combined with a 20×9–cm strip vascularized fasciae lata was raised from his left thigh (Fig. 1B). Under the operative microscope, the pedicle of the ALT composite flap was anastomosed to the left inferior epigastric vessels. The donor thigh was covered by split thickness skin grafting. Reconstruction of the abdominal wall was done as described above. The patient's postoperative course was uneventful, and the wound healed without any complications. Magnetic resonance imaging scans of the abdominal wall performed at 3 months postoperatively showed a good continuity of the reconstructed abdominal fascia without herniation (Fig. 1C). At 1.5 years postoperatively, the patient resumed his daily ambulating activities normally (Fig. 1D). The isokinetic concentric muscle power of the trunk flexion and extension showed a mild weakness of the trunk flexion in the peak torque extension/flexion ratios (Table 2). The range of motion of the donor thigh and knee joint maintained full flexion and extension. The isometric power evaluations of the ratios of donor thighs at 30 and 60 degrees flexion and the isokinetic tests revealed a deficit of nearly 10% as compared with the healthy opposite thigh (Table 3).

FIGURE 1. (A) 64-year-old male with full-thickness abdominal wall defect after laparotomy due to hollow organ perforation including skin and corresponding parts of the abdominal fascia. (B) Design of a 22×10–cm composite anterolateral thigh myocutaneous flap including a 20×9–cm strip of vascularized fascia lata (arrowhead) at the left thigh. (C) Magnetic resonance imaging scans of the abdominal region demonstrating continuity of the reconstructed abdominal wall without ventral herniation at 3 months postoperatively (arrowhead). f, fascia lata graft. (D) The appearance of the reconstructed abdomen 1.5 years postoperatively.

Case 2

A 26-year-old female sustained a full-thickness abdominal wall defect after a blunt abdominal trauma, which necessitated a hepatic lobectomy. The abdominal wall defect measured as 28×12 cm (Fig. 2A). For reconstruction, a 29×12–cm composite ALT myocutaneous flap combined with a 22×12–cm vascularized fasciae lata strip was designed at the left thigh (Fig. 2B) and harvested with the lateral circumflex femoral vessels. The fascia strip was sutured to the remnants of abdominal anterior and posterior fascia sheath. End-to-end microvascular anastomoses were performed to the deep inferior epigastric vessels. The donor thigh was covered by split thickness skin grafting. The wound healed uneventfully. After 6 months, the patient ambulated well (Fig. 2C). Kinetic communicator machine measurement was performed at 1 year postoperatively. The peak torque extension/flexion ratios showed a mild deficit of the trunk flexion (Table 2). The isometric power evaluations of the ratios of donor thighs revealed a nearly 45% deficit, and the isokinetic tests revealed a deficit of nearly 50% as compared with the healthy opposite thigh (Table 3).

FIGURE 2. (A) 26-year-old female who sustained a blunt abdominal trauma with a full-thickness supraumbilical midline abdominal defect (29×12 cm). (B) Design of a composite ALT myocutaneous flap including a vascularized fascia lata strip (22×12 cm) from the left thigh (arrowhead). (C). The appearance after reconstruction of the abdominal wall defect 6 months postoperatively.

DISCUSSION

The reconstruction of composite abdominal defects that include the skin, rectus abdominis muscle, and fascia sheath with visceral organ exposure is of complex nature.¹ The ideal reconstruction restores both the functional and esthetic integrity of the abdominal wall. The use of autologous tissue for definitive reconstruction of large abdominal wall defects minimizes the risk of hernia and avoids problems associated with synthetic materials.^13–14 Although conventional approaches, such as a skin graft applied directly on the peritoneum and/or intestine⁶ and local, regional, and distant flaps have been mobilized from the adjacent area, are effective in covering an open wound,^2,7 they generally require several operations to reconstruct the composite defect. Furthermore, though acceptable contour have been achieved by such methods, problems such as infection, hernia, and fistulous tract formation are not uncommon complications associated with these treatments,^4,20 and overall results regarding both recipient and donor sites are still not idea.

As mentioned above, multiple stages for reconstruction of the abdominal wall are time-consuming and tedious.^10–12 On the reverse, a one-stage reconstruction associated with free-tissue transplantation offers the advantages of diminishing morbidity, costs, and social impact.^10–12,16 Furthermore, the advantages of a reconstruction by using a composite free-flap with vascularized fascia include rapid healing, high resistance to infection, decreased scarring and adhesions, and a reduced hospitalization period.^11,16

The free ALT flap alone or combination of vascularized fascia lata flap for reconstruction of soft tissue defect has been reported.13,16,18–20 However, for reconstruction of full-thickness abdominal wall defects, the ALT composite flap with fascia lata for reconstruction of abdominal composite defect is rare. The pedicled ALT flap alone can be used successfully for reconstruction of lower abdominal wall defects.¹³ However, one disadvantage is its limited range of orientation, which frequently makes the use of a free flap necessary.¹³ Kimata et al have described reconstruction of abdominal composite defects using the free ALT flap alone without fascia lata.¹³ The extensive double flaps combined with free tensor fasciae muscle flap and ALT flap, also recommended by Sasaki et al, are demanding, time-consuming, and create a rather large donor defect.¹⁴ Moreover, in those publications,^13,14,30 objective assessment of the abdominal wall strength and of the donor sites after reconstruction is pending. In the present study, four patients could coordinate and perform all of these examinations by using Cybex communicator machine. These results showed mild weakness of the isokinetic eccentric, and concentric strength of trunk flexion was observed though there were no obvious abdominal herniation complications. The deficit of flexion in the reconstructed abdominal wall may result from a less dynamic excursion of the vascularized fascia lata. Vascularized fascia may mimic a fascia sheath, but it lacks the muscle-synchronized excursion properties, which the original muscle and fascia sheath structure has. In this study, we harvested the free composite ALT myocutaneous flap with vascularized fascia lata including a cuff of vastus lateralis muscle and innervated femoral motor nerve. We did not suture with the recipient motor nerve to act as a functional muscle. However, we could not account whether the flap reinnervated or not. The results showed weakness of the isokinetic eccentric and concentric strength of trunk flexion. These indicated that this composite ALT myocutaneous flap would not reinnervate due to lack of dynamic muscle-synchronized excursion. It would improve the functional results if we harvested as a functional muscle transfer for huge abdominal wall defect in the future. Though a mild abdominal flexion deficit was evident, all patients were satisfied in their daily ambulating activities within a follow-up time of at least 1 year. However, it still needs to increase the case number to decrease the selective bias in statistical analysis of functional outcome.

The vastus lateralis muscle is the largest compartment of the quadriceps femoris muscle that acts as the prime extensor of the knee joint with a concentric contraction.^19,23,24 In the presented cases, all composite ALT flaps needed intramuscular dissection of the pedicle, and a cuff of vastus lateralis muscles for adequate bulkiness was included. This induced a partial or complete interruption of the vastus lateralis muscle innervation, respectively. Both the isokinetic concentric and eccentric contraction tests of the quadriceps femoris muscles and the isometric power test at 60 degrees flexion of the quadriceps showed deficits ranging from 9% to 51% or 3% to 47% at the donor thighs as compared with the opposite normal thighs. The high variation in both test results can be explained by the different amounts of muscle and of fascia lata, which were included in the respective flaps as also shown in the presented case reports. Thus, a small amount of muscle with preservation of the motor nerve combined with a narrow strip of vascularized fascia lata results in lesser objective donor site morbidity. However, the detected deficits did not interfere with the patient's daily activities subjectively.

In summary, the composite ALT flap with vascularized fascia lata has shown to achieve acceptable results in composite abdominal wall reconstruction. Donor site morbidity though objectively existent is minimal subjectively. This technique is proposed as alternative option for reconstruction of large abdominal wall composite defects.