ORIGINAL PAPER

Primary thinning of the anterolateral thigh flap in Caucasiansis a safe technique

Nikolaos Ioannis Karmiris & Marios Nicolaou &

Mansoor S. Khan

Received: 21 November 2013 /Accepted: 23 March 2014# Springer-Verlag Berlin Heidelberg 2014

AbstractBackground The anterolateral thigh (ALT) perforator flap is awell-described and versatile flap, regularly used forresurfacing and reconstructing soft tissue defects, but it isoften too bulky to produce an aesthetically satisfactory result.Although primary thinning of the ALT has been successful inEastern populations, studies have demonstrated that this maybe inadvisable in Caucasians. This is the biggest clinical studydemonstrating the clinical safety of primary thinning of ALTflaps in Caucasians.Methods A retrospective analysis was performed betweenJanuary 2009 and August 2011 on 57 patients (mean age 43)undergoing ALT free flap reconstruction by three surgeons.They were all thinned via sharp dissection using loupe mag-nification except for 1–2 cm around the perforator by remov-ing the larger fat globules of deep fascia and preserving thesuperficial fat layer. The resultant flap thickness was approx-imately 6 mm.Results In 77 % of cases, the flap was used for lower limb,16% for upper limb and 7% for head and neck reconstruction.The mean flap surface area was 124 cm2. There was one flaploss (1.8 %) and three flaps returned to theatre for periopera-tive complications.Conclusions Careful primary thinning of ALT flaps is safe inCaucasian populations and can achieve improved cosmeticresults.Level of Evidence: Level IV, risk/prognostic study.

Keywords Anterolateral thigh flap . Primary thinning .

Caucasians

Introduction

Since first described in 1984 [1], the anterolateral thigh (ALT)has become a workhorse flap for the reconstructive plasticsurgeon.

One of its drawbacks, especially in Western populations, isits large bulk, which can be undesirable especially whenresurfacing thin defects such as on the dorsum of the handor foot. Additional procedures such as liposuction or open flapthinning are commonly required to improve the aestheticresult [2]. Despite primary flap thinning being somewhat acontroversial topic especially as there are theoretical risks offlap compromise, a number of techniques have been de-scribed. Yang et al. [3] presented a modified perforator micro-dissection technique used in 18 Chinese patients with noadverse effects. Other clinical and anatomical studies alsoshowed that primary thinning of ALT flaps in Eastern popu-lations is safe [4–7]. However, there are no clinical studies toevaluate the safety of primary flap thinning in Caucasians.Cadaveric studies in Western populations postulated an in-creased risk of vascular injury when thinning was performedup to 1 cm from the perforator [8]. There has been some workof more accurately defining arterial and venous anatomy usingCT angiograms [9] concluding that disturbance of vesselswithin the suprafascial plexus attributes to a reduction invascular territory. However, the two main weaknesses werethat the study related to cadaveric flaps and not in vivo as wellas the fact that the study was restricted only to patients fromWestern population.

N. I. Karmiris (*) :M. Nicolaou :M. S. KhanDepartment of Burns, Plastic and Reconstructive Surgery, OdstockCentre, Salisbury, Wiltshire, UKe-mail: nikoskarm@yahoo.gr

Eur J Plast SurgDOI 10.1007/s00238-014-0955-3

Finally, a systematic literature review [10] analysed11 articles that fulfil the criteria, concluding that prima-ry thinning of flaps >150 cm2 is not advisable, espe-cially in Western population, because of high rate ofpartial necrosis.

This is the first and biggest clinical study demon-strating the clinical safety of primary thinning of ALT flapsin Caucasians.

Patients and methods

Between January 2009 and August 2011, data from 57 con-secutive patients (47 men, 10 women) who underwent ALTfree flap reconstruction performed by three surgeons wasretrospectively analysed. All the ALT flaps were thinnedprimarily using the technique described below.

Operative technique

The ALT flaps were raised using a subfascial approach aspreviously described [7, 11–15] using loupe magnification.The subfascial approach was used because it provides quickerand easier dissection as well as maintaining the fascia hascontroversial and not significant long-term advantages for thepatient’s donor site [16, 17]. We mainly harvested our freeflaps based on a single perforator. Where anatomically possi-ble, two perforators were carefully dissected in order to im-prove the perfusion of larger flaps. All but three donor siteswere closed directly.

Thinning technique

Flaps were thinned after pedicle division using loupe magni-fication. The deep layer of fat was removed up to the junctionwith the superficial fascia using tissue dissection scissors. Themain linking vessels are found superficial to this layer so careshould be taken not to go beyond this layer. A 1–2-cm islandof all layers of fat was also preserved around the main pedicle.To avoid vascular compromise, thinning should not result inflaps thinner than 5–7 mm. However, the main author hasrecently started even microthinning ALT flaps dissectingaround the pedicle when necessary to enable even thinner flap[3].

Case report

A 14-year-old child was seen in a burns clinic with a tightcontracture of the elbow following a burn 3 years previously(Fig. 1). Subsequently, the contracted skin was excised and a

23×10-cm (230 cm2) ALT was used to resurface the defect.The flap was thinned intraoperatively to 6 mm using thetechnique described above to match the thickness of the defect(Figs. 2 and 3). There were no post-operative complications,and the patient was discharged 5 days post-op. At routinefollow-up, the range of motion had dramatically im-proved with a well-contoured and good aesthetic result(Figs. 4 and 5).

Case report

A 21-year-old man was seen with a stage two malignantmelanoma on the anterior ankle and required wide localexcision and sentinel lymph node biopsy (SLNB). An ALT

Fig. 1 Burn scar, causing restriction of elbow flexion pre-op

Fig. 2 ALT flap after primary thinning

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was designed and harvested to reconstruct a 7×6-cm defect.The flap was thinned intraoperatively as previously de-scribed to a 5-mm thickness (Fig. 6) and inset into thedefect (Figs. 7 and 8). There were no post-operativecomplications, and the patient was discharged 6 dayspost-operatively.

Results

In total, 57 ALT flaps in 57 patients were included in thisstudy. The mean age was 43 (range 14–75). No obese patientswere included in the study (BMI range 23–30).

Forty-four flaps (77 %) were used for lower limb, nine(16 %) for upper limb and four (7 %) for head andneck reconstruction. Forty-six flaps were used for trau-matic defects, five for cancer reconstruction and six forscar resurfacing.

Ninety-three percent of the flaps were raised by one ofthree senior surgeons with the remainder raised by a morejunior surgeon under direct supervision. The senior surgeonsperformed 87 % of the venous anastomoses and 80 % of thearterial anastomoses. Ninety-two percent of arterial anastomo-ses were end to end with the donor vessel using interrupted 9/0nylon sutures with the remainder being end to side. Two vein

Fig. 3 Immediate post-op result

Fig. 4 Three weeks post-op. Patient had full range of movement of theelbow

Fig. 5 Almost perfect contour with the elbow and the arm surface area

Fig. 6 ALT flap after primary thinning and anastomoses, before inset

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grafts were required for the arterial anastomoses. A similartechnique of interrupted sutures was used for the venousanastomoses except in three cases where a venous couplerdevice was used [GEM COUPLER]. Intraoperative anasto-motic revision (two arteries and three veins) was required for8.8 % of flaps. The mean ischaemia time was 55.17 min(range 19–108 min) with mean length of operation 5.8 h(range 4–11 h). The mean flap surface area was 126 cm2

(range 18–330 cm2). Primary donor site closure was possiblein 95 % of patients.

There was one complete flap failure (1.8 %) secondary tovein thrombosis (despite two re-explorations). There werethree further returns to theatre (two for evacuation ofhaematomas and one for vein thrombosis), which resulted in

flap survival. Additionally, there were two partial flap necrosisrequiring flap debridement. One resulted following adirect fall on the flap post-discharge, and one was compro-mised secondary to an infected haematoma 2 weekspost-procedure.

Discussion

The ALT is a versatile flap with multiple advantages: avery large skin paddle with minimal donor site morbid-ity and an acceptable aesthetic outcome even whendonor site grafting is required [16]. It also has a longpedicle of reasonable calibre for microsurgical anasto-moses. It can be harvested and anastomosed, in mostcases, without the need of changing the position of thepatient intraoperatively, often permitting a two-team ap-proach to the surgery. One of its main disadvantagesespecially in Caucasians is its larger bulk [18], oftenrequiring secondary debulking procedures in order toachieve an acceptable aesthetic result that can add tothe stress of the patient and overall cost of theprocedure.

The first clinical report of primary thinning of theALT was by Koshima et al. in 1993 [4]. Since then,these authors published further four reports all of whichconcluded that primary thinning of ALT is safe as longas a large zone of safety around the perforator is pre-served and defatting is only done at the periphery[19–22]. Kimura further suggested that the safety dis-tance is 9 cm from perforator entry [7]. All of thesestudies were on Eastern populations.

In Caucasians, reports have not been as favourable. Anumber of cadaveric studies suggest that primary flapthinning is unsafe [8]. However, this report fails to takeinto account the differential behaviour of dynamic andanatomical circulation. Newer cadaveric studies usingmodern techniques demonstrated the presence of a densesuprafascial plexus perfused mainly by recurrent flowthrough the subdermal plexus [9]. It is this enhancedvascular flow that may explain why flap thinning mayallow flap survival.

Clinical studies in Western populations are limited. Rosset al. [23] attempted primary thinning in four patients forintraoral reconstruction with 50 % flap failure rate. Theyrecommended to never thin an ALT flap. Loreti et al. in2008 [24] published 25 cases of chimeric thinned ALT flapswith no losses. They reported that leaving a 5-mm cuff ofsubdermal fat around the perforator vessels, preserving 2–3 mm of superficial fat below the subdermal plexus to prevent

Fig. 7 Immediate post-op photo

Fig. 8 Minimal difference of the ankle contour

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injury to the plexus, is safe. However, all flaps were taken witha 0.5-cm cuff of vastus lateralis muscle, and the thickness ofall trimmed flaps were 1–2 cm. Additionally, the flap meansize was only 67.5 cm2 suggestive of their use for small, thindefects. Finally, Adani et al. [25] demonstrated completesurvival of primarily thinned ALT flaps for dorsal hand defectreconstruction in all nine patients in whom the procedure wasperformed. The average size of these flaps was also only76.4 cm2.

Our study represents the largest clinical study of primaryALT thinning in Caucasians with the largest average flapsurface area and demonstrates that primary flap thinning issafe in these populations provided it is performed carefullyallowing a cuff of 1–2 cm around the main perforator. Similarto Koshima, we have also found that microscope microdis-section can achieve further flap thinning of 3–5 mm, but asCaucasians are fatter [18], this has to be done meticulously. Ithas many advantages of conforming to the exact defect to bereconstructed and obviates the need for additional procedures.The technique is not time consuming and offers a faster patientrecovery time and return to normal activities in a single-stageprocedure with its associated psychological advantages. Thereare also significant cost savings by avoiding furtherprocedures.

In summary, this study has shown that primary thin-ning of ALT flaps in the Western population, providedis done correctly, is a safe, effective and quick tech-nique. It saves the patient from a second thinningoperation and the national health system from anotheradmission and can provide a thin, pliable andvascularized tissue for covering a wide range of defectsin all parts of the body.

Acknowledgments I would like to express my gratitude toMs. CarolineMcGuiness and Mr. Naveen Cavale, consultant plastic surgeons, becausethey provided me important data for this study.

Conflict of Interest None

Ethical Standards The study has been approved by the appropriateethics committee and have therefore been performed in accordance withthe ethical standards laid down in the 1964 Declaration of Helsinki and itslater amendments. All persons gave their informed consent prior to theirinclusion in the study. Details that might disclose the identity of thesubjects under study were omitted.

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