Thin Anterolateral Thigh Perforator Flap In Upper Limb Reconstruction

INTRODUCTION

To achieve a satisfactory functional and aesthetic outcome, upper extremity soft-tissue covering necessitates the use of a thin and flexible flap.¹ The knowledge of the flaps'  vascular anatomy enables the surgeons to harvest thin flaps at the superficial fascial level and super-thin flaps at the level of the thin subcutaneous fatty layer.²  Pure skin perforator flaps to the level of the dermis depending on a branch of the superficial circumflex iliac artery and the superficial inferior epigastric artery also harvested by Narushima et al.^3,4

  The anterolateral thigh perforator (ALT) flap was first described by Song et al,5 depends on the perforators of the descending branch of the lateral

circumflex femoral artery. There are several advantages to the ALT flap, including its ease of harvesting, little donor site morbidity, and satisfactory outcomes ^5,6, the vascularized fascia lata that can serve as a gliding surface for tendons, and it is also utilised in the restoration of difficult upper extremity wounds with vascular deficit by using venous grafts.⁷ 

The primary defatting of the anterolateral thigh flap results in a malleable flap that can replace the upper extremity thin skin and contour. It also eliminates the need for a second procedure to thin the flap and remove extra flap bulkiness, which can limit range of motion if not addressed. As a result, this primary thinning enhances function and quality of life while reducing total hospitalizations and expenditures.^8,9,10 

The aim of this study was to assess the functional and aesthetic outcomes of complicated upper extremity injuries by utilizing a thinned ALT flap.

MATERIALS AND METHODS

This study was conducted at the Plastic and Reconstructive Surgery Department, Al-Azhar University Hospitals from July 2018 to October 2021 and included 20 patients with complex defects over the upper extremity. The defects were due to post‑traumatic deformities and postburn scars. Exclusion criteria included patients with peripheral vascular diseases and severe chronic illnesses. Functional and aesthetic outcomes were also assessed and reported on.

Ethical approval

The Ethical Research Board (ERB) of Al-Azhar University's Faculty of Medicine in Cairo, Egypt, approved the study. Before the study proceeds, all patients are assigned informed consent after the obvious explanation of the possible adverse events.

Aesthetic evaluation

The aesthetic results were assessed by four plastic surgeons, patients, or patient relatives in the case of a child, using a five-point likert scale.¹¹ The points on the scale are colour matching, contouring, texture, distribution of the hair, and satisfaction. Each item has points from one to five, with one being the worst and five being the best. The overall score (min, 5 & max, 25) was categorized as follows: 5 to 9, poor; 9 to 13, bad; 13 to 17, fair; 17 to 21, good; and 21to 25, very good. The panel's plus patients' total scores were added together to produce the final score. 

Functional evaluation

The Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score has been used for subjective self-assessment. 11-15 indicate no difficulty, 16-40 indicate "problem, but working," while >40 indicates "unable to work."

Surgical technique

In patients with acute damage, the wound was properly irrigated first, then serially debrided till the flap became ready for reconstruction. If there was any associated structural injury, it was repaired first, as soon as the wound was suitable. A vertical line was marked from the anterior superior iliac spine to the lateral superior aspect of the patella while the patient was in a supine position. Draw a circle with a radius of 3 cm at the midway of this straight line. The perforators were detected inside and adjacent to the drawn circle using a handheld 8 MHz Doppler.¹¹ The flap's dimensions had been determined based on the defect size, with an additional 1–2 cm added to the defect's measurements.  A subfascial or suprafascial technique was used to harvest a thin ALT flap. In the case of the subfascial technique (Figure 1), the standard ALT flap was harvested initially. A medial incision was performed down to and through the thigh fascia to expose the rectus femoris muscle. The vastus lateralis muscle was then split from the rectus femoris muscle by retracting it medially, exposing the septum. Retrograde dissection was performed to skeletonize the septocutaneous perforator. Intramuscular dissection was continued till it reached the descending branch of the lateral circumflex femoral artery. The lateral cutaneous nerve of the thigh was carefully dissected away from the pedicle, then lateral incision was performed. The primary thinning then started from periphery, almost above the superficial fascia, between the superficial small rounded and the deep, big, diagonally fat lobules, by using scissors or electrocautery. ¹²     In the suprafascial plane (figure 2), the flap can also be harvested by detecting and identifying the perforators that pierce the fascia and protect them with a cuff of adjacent tissue.¹³ In most circumstances, the donor area could be closed with direct closure, but in patients where a wide flap is desired, a skin graft or a locally flap may be required to close the donor area.

Statistic evaluation

Data were analyzed using IBM© SPSS© Statistics version 26 (IBM© Corp., Armonk, NY) and MedCalc® Statistical Software version 20 (MedCalc Software Ltd, Ostend, Belgium; https://www.medcalc.org; 2021). Paired numerical data is compared with the paired-samples t-test. Correlations between numerical variables are examined using the Pearson correlation (Pearson r). Correlations of numerical variables with binary or ordinal variables are examined using point-biserial (rpb) or rank-biserial (rrb) correlation.

RESULTS

Patients

The demographics of the patients, their comorbidities, and the characteristics of the injury was collected (Table 1). The mean length of the flap was 18.5 cm (range 9–32), the mean width of the was 9.1 cm (range 6–15), and the surface area was 185 cm2 (range 55-434). The initial flap had a mean thickness of 21 mm (range 15-32), while the flap after thinning had a mean thickness of 5 mm (range 4-9). The donor site was directly closed in 17 cases, with three cases requiring skin graft.

Table 1:  Patient’s demographics, chronic illness, cause of injury and details of the flap.

Post operative complications (table 2)

Three patients suffered hematomas from initial thinning, resulting in total flap loss. Flap ischemia had occurred in one patient; during re-exploration, thrombosis of the artery was detected, removed and re-anastomosis was done with complete salvage of the flap. Partial necrosis of the tip has occurred in two patients, with one having a flap surface area of 258 cm2 and thickness was7 mm. The other patient had a flap surface area of 220 cm2 with a thickness of about 6 mm. Both flaps were treated in 3 weeks by secondary intention. Three flaps developed infections that required only antibiotic therapy. Re-operations were done three weeks following surgery, with STTG performed in three patients who experienced total flap loss. Tenolysis was done on one patient. Two patients needed tendon spacer and a tendon graft. Flap thinning and defatting was performed for one patient, while two others had flap division and re-fashioning to create new web spaces.

Table 2: Incidence of complications and adverse outcomes in the study population

Functional and aesthetic results

The panel mean total aesthetic score for the five items was good (Table 3) 20.9 (STD 2.9, ranging 13.5–24), that was greater than the patients' mean total score of 19.2 (STD 3.6, ranging 13–24) (good). The patients' total aesthetic scores were significantly related to the panel scores. (Paired-sample t-test, P- Value 0.018). The mean Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score was 23± 10 (3 to 41). Eight cases scored the highest score that ‘had no difficulty’, eleven cases scored ‘had a difficulty but work’ and only one case recorded ‘unable to move’.  The correlation between the thickness of the flap and QuickDASH score before and after thinning was insignificant. (p- value 0.848, 0.988).

Table 3: Comparison of aesthetic scores as rated by physicians or patients

Case presentation

Case 1

A male patient 24 years old with post traumatic amputation of rt thumb, no history of systemic diseases or previous surgery. Subfascial harvesting technique for elevation of ALT followed by primary defatting as showed in (figure 1). Quick DASH score of the patient was 21 which means that the patient had “a difficulty but work”. The panel score was 4 as regard color, 3.5 as regard contour, 4 as regard texture, 3 as regard hair and the overall satisfaction was 4.The patient 5 point- likert scale was 4.5 as regard color, 3 as regard contour, 3.5 as regard hair and texture and overall satisfaction was 3.5.

Fig. 1: A: male patient 24 years old with post traumatic amputation of rt thumb. B: ALT flap marking. C sub fascial harvesting and primary thinning of contralateral ALT flap. D: Preparation of recipient vessels. E: post operative view after coverage of the raw area. 

Case 2

A male patient was 45 years old, with post traumatic soft tissue defects at the dorsum of the medial 4 fingers, patient was hypertensive with no history of drug intake or previous operation, suprafascial harvesting technique for elevation of ALT followed by primary defatting as showed in (figure 2), 3 weeks later separation of the flap to reconstruct the medial four fingers. Quick DASH score of the patient was 23 which means that the patient had “a difficulty but work”. The panel score was 3 as regard color, 4 as regard contour, 4 as regard texture, 3 as regard hair and the overall satisfaction was 3.5. The patient 5 point- likert scale was 4 as regard color, 4 as regard contour, 3 as regard hair and 3.5 texture and overall satisfaction was 3.5.

Fig.2: A: male patient 45 years old with post traumatic soft tissue defects at the dorsum of medial 4 fingers. B: ALT flap marking at the contralateral thigh. C: suprafascial harvesting and primary thinning of contralateral ALT flap. D: in setting of the flap over the defect. E:  3 weeks later post operative view after separation of the flap to reconstruct the finger.