Bilateral Lower Limb Injuries and the Need for Two Free Flaps: Simultaneous or Sequential

Abstract

Objective  To determine the choice of flap cover for patients presenting with bilateral lower limb trauma requiring free flap cover and to derive a step-wise guide to the planning of bilateral lower limb free flaps.

Materials and Methods This was a retrospective study of patients over a 20 year period from 2000 to 2020 who presented with bilateral lower limb defects following trauma and were managed with two free flaps for wound cover, done either simultaneously or sequentially in the same admission.

Results Of the 11 cases with 22 defects, there were 3 re-explorations with 1 flap loss managed with delayed fasciocutaneous flap cover. Donor morbidity was minimal requiring aspiration of seroma for 1 patient and secondary SSG for recipient area graft loss over muscle flap in 2 patients.

Conclusion Use of single donor site ensures economy of time and tissue with the use of skin and muscle chimeric flaps. Harvesting of twin ALT flaps or the use of lattisimus dorsi as one of the flaps requires a 2 stage surgery to avoid prolonged operative time.

Keywords

bilateral - lower limb injury - free flap - ALT-rectus femoris flap - fillet free flap - foot defect

Background

Bilateral lower limb injury following road traffic accidents can often result in defects in both limbs, each of which deserves a flap cover for exposed bones and fractures. There are few studies reporting the use of bilateral single-stage free flaps in compound lower limb injuries. For this uncommon but important clinical presentation, the choice of flap donor site needs to be clear. The authors seek to highlight a consecutive series of 11 patients with 22 defects.

The aim of the study was to retrospectively analyze all cases of bilateral lower limb trauma that needed two free flaps for both sides in the same inpatient admission for the choice of flap and success of outcome.

Objectives: The primary objective was to determine the choice of flap depending on the location and size of the defects. The secondary objective was to derive a step-wise guide to the entire procedure in any bilateral lower limb free flap.

Introduction

Free flaps are a well-established method of coverage for lower limb defects following injuries.[1] Haykal et al[2] state a significantly lower flap failure rate when intervention is done within 72 hours of lower limb trauma. Motor vehicle or the more severe rail track accidents can result in moderate to severe injuries in both lower limbs leading to a challenge for the surgeon in planning debridement, skeletal fixation (in case of unstable fractures or dislocations), and wound coverage.

Provided the patients are triaged well and life-threatening injuries of other systems have been excluded, free flaps could be the most optimal way to ensure early coverage bilaterally.

Free flaps for the coverage of bilateral defects have been reported earlier in the literature—using the same flap or two different flaps, although some have been used for nontraumatic indications.[3] [4]

When two different donor sites are indicated for simultaneous coverage of bilateral limb defects, there has to be a balance between adequate coverage and minimal donor complications. Often a single donor site can offer two different flaps to be harvested for coverage of two defects. The successful execution of bilateral free flaps either simultaneously or sequentially (due to the logistics of choice of flap and operative positioning) needs a coordinated surgical plan to permit execution in optimal time.

In rare cases, the type of injury might also allow for the use of filleted tissue from an unavoidable limb amputation, as a free flap, to expedite coverage where needed. Such a technique has been reported in the literature for defects in both the upper and lower limbs.[5]

The aim of this retrospective study was to determine the success of the bilateral free flap procedure in bilateral lower limb trauma and the rationale for flap choice to achieve adequate coverage with minimum donor morbidity.

Materials and Methods

Data were retrieved for all free flaps done for acute limb trauma from 2000 to 2020. The number of patients who required two free flaps in the same admission was 18. There were 11 patients in whom two free flaps were done for bilateral lower limb injuries only. Data collected included the type of flap, location and size of the defects, recipient pedicles and the type of anastomosis, the incidence of re-exploration, and any flap loss—total or partial.

Surgical Technique Using One or Both Thighs as the Donor Site

Debridement was done under tourniquet control; recipient pedicles were dissected with the tourniquet still inflated. After checking the adequacy of the flow, the tourniquets were completely removed and appropriate skeletal fixation was done.

The use of the latissimus dorsi flap in any individual case implied that the second flap would be done on the next operative day. This was due to the need for a lateral decubitus position in latissimus dorsi harvest. Executing a second free flap simultaneously would have prolonged the operative time ([Figs. 1] and [2]).

Fig. 1 (A) Right side compound ankle fracture. (B) Left foot degloving with skin loss. (C) Gracilis flap anastomosed to the posterior tibial vessels for coverage of the exposed ankle joint. (D) Latissimus dorsi muscle flap used for coverage of skin loss of the heel, medial ankle, and sole.

Fig. 2 (A, B) Frontal and medial views. (C, D) Posterior and lateral views of the patient after 18 months of follow-up.

The choice of either one thigh or both thighs for the two flaps (in those cases where the latissimus dorsi flap was not chosen) was made after an assessment of the size of the defect.

When a single thigh was chosen, it was the thigh with the lesser trauma, to facilitate the elevation of the anterolateral thigh (ALT) and rectus femoris as a composite flap. After detachment, the flap was divided into two flaps and laid in the appropriate recipient site ([Figs. 3] and [4]).

Fig. 3 (A) Skin degloving in the proximal medial foot and midfoot (left side). (B) Compound fracture lower third leg with degloving (right side). (C) Defect after debridement (left). (D) Exposed fracture of the lower third after debridement (right). (E) Pre-op X-ray of the right leg. (F) Harvested composite anterolateral thigh (ALT) rectus femoris flap after separation on table (harvested from the left thigh).

Fig. 4 (A) Rectus femoris muscle covering the exposed leg fracture. (B, C) Anterolateral thigh (ALT) flap for coverage in the left foot. (D) Healed leg right side after 6 months. (E) Healed wounds of the left foot.

When both thighs were chosen, dissection started with the flap intended for the larger or more complex defect using the contralateral thigh. Once the perforator anatomy and source vessel were confirmed, dissection of the other thigh for ALT flap was started ([Figs. 5] and [6]).

Fig. 5 (A) Left compound lower third fracture. (B) Left wound after debridement. (C) Right dorsum foot after debridement. (D) Anterolateral thigh (ALT) flap from the right thigh for the left leg. (E) ALT flap for the right foot from the left thigh.

Fig. 6 Both wounds healed at 6 weeks of follow-up, but both donor sites needed split skin graft on account of the width of the flap harvested.

ALT flap elevation was standard starting with an anteromedial incision and subfascial identification of skin perforator and retrograde dissection to the source vessel.

The flaps were circumscribed after taking defect patterns on either lower limb and both flaps were detached simultaneously; the donor raw areas were first reduced.

Prior to the anastomosis, the flap was anchored at the recipient site with few stiches to stabilize it. Anastomosis was done simultaneously on both sides. The use of a hand trolley with the hip in abduction was preferred for anastomosis, on the side with the lesser injury, usually at the foot, to provide space for anastomosis in the opposite limb.

After flap perfusion was confirmed, 50% flap inset was completed. Split skin graft was then harvested from the donor side with the lesser flap dimension. The remaining 50% of the flap inset was completed and the donor and/or recipient side graft was placed. This order of flap inset ensured optimal usage of the operative duration when two flaps are being done in a single stage.

Noncompressive dressing with extra padding ensured that there would be less soakage from the donor area and no deleterious pressure effect would be placed on the flaps distally.

Results

The bilateral lower limb trauma in 2 of the 11 patients were following railway injuries and 9 were following motor vehicle accidents; there were 9 males and 2 females with a mean age of 34 years (range: 24–50 years).

The patients were considered for free flaps only after a systemic clinical evaluation and investigations excluded any kind of head, spine, chest, and abdominal trauma. There were no other proximal skeletal or soft-tissue injuries in either lower limb. There were no comorbidities in any of the patients.

Only the patients with railway accidents had other limb injuries—multiple digital amputation in both hands in one patient and nonreplantable left upper limb amputation in the other patient.

Six of the 11 patients had compound lower third leg fractures. All of these were Gustilo–Anderson grade IIIb injuries and none were grade IIIc with critical ischemia.

The flaps included the latissimus dorsi muscle, the ALT, rectus femoris muscle, and the gracilis; fillet free flaps and anteromedial thigh (AMT) flaps were used in one case each. The size of the defects and the location are presented in [Table 1].

Table 1 Details of the injury location, defect size, and choice of flap

Location 1	Location 2	Flap 1	Flap 2	Defect size (cm)	Defect size (cm)
Foot	Foot	ALT	Latissimus dorsi	15 × 12	18 × 12
		ALT	AMT	10 × 10	10 × 8
		ALT	Rectus femoris	10 × 12	15 × 8
		Fillet flap[a]	Fillet flap[a]	15 × 8	12 × 10
Foot	Leg	Latissimus dorsi	Gracilis	20 × 12	15 × 10
		ALT	Rectus femoris	15 × 12	14 × 8
		Gracilis	Latissimus dorsi	15 × 10	20 × 15
		ALT	Rectus femoris	17 × 15	15 × 8
		ALT	ALT	18 × 12	12 × 10
		ALT	ALT	15 × 15	18 × 10
Leg	Leg	ALT + rectus femoris	ALT + rectus femoris	18 × 14	15 × 12

Abbreviations: ALT, anterolateral thigh; AMT, anteromedial thigh flap.

^a Radial artery forearm and ulnar artery forearm flaps were filleted from an unsalvageable upper limb above the elbow amputation stump.

The time frame for flap cover was as follows: debridement, fixation, and both flaps in the same procedure were done in 7 cases; a gap of 12 hours between the two flaps in three cases; debridement and fixation followed by two flaps after 12 hours in one case (“12 hours” refers to the next operative day after the first flap; [Table 2]).

Table 2 Details of how the flaps were executed: simultaneous or sequential

Procedure	Flap 1	Flap 2	No. of patients
Debridement, fixation followed by two flaps simultaneously after 12 h	Composite ALT Rectus femoris flap	Composite ALT rectus femoris flap	1
Debridement, fixation and two flaps simultaneously	ALT	ALT	2
	ALT	AMT	1
	ALT	Rectus femoris	3
	Fillet flap	Fillet flap	1
Two flaps with a gap (second flap after 12 h)	Latissimus dorsi	Gracilis	2
	Latissimus dorsi	ALT	1
Total flaps			11

Abbreviations: ALT, anterolateral thigh; AMT, anteromedial thigh flap.

All the anastomoses were done end to end to the anterior or posterior tibial vessels, as appropriate and using deep veins as the recipient veins.

There were three re-explorations, of which one was arterial and two were venous; the arterial problem was salvaged using an interposition vein graft successfully; one of the cases of venous blockage could not be salvaged in spite of two redo anastomosis using a vein graft. This was a rectus femoris muscle used for coverage of an ankle fracture. Flap debridement was followed by a distally based delayed fasciocutaneous flap for coverage of the critical areas.

Among the nine ALT flap donor sites, only three could be closed primarily. There were no infections at the donor sites. Seroma in one of the latissimus dorsi donor site needed aspiration twice and resolved with further compression dressings. In the patient who had two chimeric ALT rectus flaps, both donor sites were closed primarily. Two patients needed secondary split skin grafting at the recipient area for graft loss over muscle flaps and one patient needed it at the ALT flap donor site.

Discussion

If the defects are symmetrically located along the long axis of both the lower limbs, like both legs or more often both feet, a single flap can be used to cover both defects using the recipient vessels from the less injured limb. Cross-leg immobilization using an external fixator is mandatory and after a suitable time the flap can be transected leaving coverage on either side. Cipriani et al[6] report three cases of bilateral lower limb defects covered using a single latissimus dorsi flap using the vessels of the lesser injured limb; one flap failed and was salvaged using a second latissimus dorsi flap. External skeletal fixator was used to immobilize both limbs.

A more elegant method would be to use two independent free flaps, thus avoiding the need to immobilize the two limbs together for 4 to 6 weeks. If so, a decision has to be made on whether a single flap donor site or multiple sites should be chosen and whether the two flaps should be done simultaneously or sequentially.

Whitney et al[7] describe the success of simultaneous free flaps in the upper limbs with comparable success rates to sequential flap cover; they do admit a higher re-exploration rate for simultaneous procedures, but the advantages far outweigh sequential free flap transfers (these were done during a second admission).

The usage of different donor sites like the back and the thigh (for a latissimus dorsi and gracilis flap) would mean performing the procedure in more than one stage to keep within reasonable operative time to prevent morbidity since a lateral position for the latissimus dorsi muscle harvest is usually inevitable.

Using a single donor site would minimize the operating time. Safak and Akyürek[8] described two different radial forearm flaps from a single forearm for coverage of two-foot defects in two patients; the compulsion of avoiding morbidity in the forearm would imply the use of this technique only for the smallest of defects. (None of the defects in this case report were more than 75 cm².)

A unique case report by Chiang and Wei[9] described the use of a split latissimus dorsi muscle (each half revascularized using the medial and main trunk of the thoracodorsal vessels) to cover two defects of the feet following acute trauma. There was no mention of the defect size, but it stands to reason that the applicability of this technique is for a combination of small and moderate-size defects only.

Chen et al[10] in 1998 reported five bilateral foot injuries covered using two different flaps from the thoracodorsal–subscapular axis—essentially combinations of the parascapular, latissimus dorsi muscle with or without the serratus anterior to maximize flap size. They described the “economy of incisions” in harvesting two flaps from the same donor site. They did not report the defect sizes to understand the limitations of using the parascapular or the serratus anterior with the latissimus dorsi.

The concept of “economy of incisions” for the thoracodorsal vascular axis is also applicable to the descending branch of the lateral circumflex femoral vessels and permits harvesting the ALT skin, the rectus femoris, or vastus lateralis from the same thigh to use as two different flaps. A second possibility is to use the ALT and AMT flaps.

Variability of the perforator of the ALT skin implies flexibility in designing flaps. Hong et al[11] described the use of the proximal perforator–based ALT or the AMT with different source pedicles as an alternative to the standard ALT flap, albeit for unilateral defects. In their cohort, 12 of 564 cases needed this “contingent” flap as the alternative to a standard ALT flap.

So, an inherent flexibility of choosing the flap or flaps after exploration will ensure successful reconstruction, if the thigh and only the thigh is considered as the donor site.

We have used the ALT skin and the rectus femoris muscle as two different flaps for coverage of three defects in our series; the primary pedicle of the rectus femoris is a constant, even though there could be variability of the skin perforator of the ALT flap.

Wei et al[12] reported the use of the rectus femoris as an alternate to the ALT flap emphasizing its reliability in 26 of 53 cases, and these were used only for coverage of lower limb defects. There was no morbidity on account of rectus femoris muscle harvest in their study.

The main drawback of the rectus femoris is that not much is expected by scoring of the undersurface of the muscle to increase the surface area coverage. This necessarily restricts its use to defects of an approximate rectangular geometry with an area not more than 150 cm².

Although objective testing after rectus femoris harvest reveals reduction in knee extension strength, there has been no clinical reduction in active range of knee motion or any subjective complaints of knee weakness in various studies.[13] [14]

In one case with a bilateral leg defect, we had the intention to cover a maximal area but with primary donor site closure; hence, the bilateral ALT and rectus femoris flaps were harvested for each defect ([Figs. 7] [8] [9]).

Fig. 7 (A, B) The right and left legs before debridement. (C, D) After debridement near circumferential loss of skin with exposed fractures. (E) Identical rectus femoris-anterolateral thigh composite flaps harvested from both thighs.

Fig. 8 (A, B) Two views of flap inset in the left leg. (C, D) Two views of flap inset in the right leg.

Fig. 9 Follow-up images after 1 year with healed fractures; note the primary closure of the flap donor sites on each thigh although split skin grafts were harvested to cover noncritical areas of both recipient sites.

According to Wong et al,[15] conventional flaps may not be large enough to optimally cover the wound. The composite flaps in their series of seven patients (in a single lower limb) had a mean area of skin coverage of 355 cm² and mean volume of the muscle flap was 210 cm³. They preferred the vastus lateralis over the rectus femoris in addition to the ALT.

In our series, six of nine (66%) ALT thigh donor sites needed split skin grafting (including the one case where both ALT and AMT flaps were harvested from the same thigh).

Lin et al[16] used the chimeric ALT and rectus femoris. In their study, 23 of 44 cases had the skin of the thigh harvested with combinations of muscle, fascia, and bone. Nine of 23 patients (40%) needed split skin graft at the thigh donor site on account of a paddle of width more than 7 cm—there was no mention of the defect sizes.

The number of patients needing split skin graft at the ALT donor site could have been reduced by harvesting flaps to cover only the critical portion of the defect, but it would not have made any change in the need for donor site in any way.

The overall complication rate (excluding flap loss) was 4 of 10 cases in our present series.

Laporta et al[17] described the use of two fillet free flaps from the foot—the sole tissue for coverage of an ipsilateral popliteal fossa defect and the dorsalis pedis fillet flap for coverage of a below-knee amputation stump. The surgery was done at 3 weeks following a mower injury to both lower limbs. The below-knee amputation was decided on account of an infected devascularized leg, but the foot and ankle were virgin to be considered for use as a fillet free flap.

In the only case of this kind in our series, we could harvest more than three-fourths of the forearm skin as a radial and ulnar forearm flap including the radial and ulnar vessels. The elbow amputation was deemed nonreplantable. Both transtarsal foot stumps had adequate coverage ([Fig. 10]).

Fig. 10 (A, B) Crushed feet following a railway accident. (C) Radial forearm flap and (D) ulnar forearm flap harvested from non-replantable above elbow amputation; (E, F) Radial forearm flap was used for the right side and the ulnar forearm flap for the left side—healed at the 1-year follow-up.

Based on the experience in the present case series, the rectus femoris is recommended for smaller defects. When flaps are chosen only from the thigh, since there is a variability of the perforator arising from the source vessel, the flap with a longer pedicle should be preferred in the limb with greater trauma. The choice of muscle against skin is solved by preferring skin in the defect that is likely to require future secondary reconstruction.

Keeping the operative time to less than 9 hours if two different ALT flaps are contemplated would mean doing the preliminary debridement and fixation and completing the flap transfers after 12 hours (the next operating day). This would be the case in all compound fractures of the lower limbs, save the most distal foot injuries on account of time needed for debridement and fixation.

Conclusion

Healthy young and middle-aged adults can undergo double free flaps for bilateral lower limb defects in the same operation safely. A single donor site ensures economy of time and donor site by harvesting the rectus femoris and the ALT skin. Harvesting twin ALT flaps is a possibility, provided the preliminary debridement and fixation are completed first to keep the operative time down. The use of the latissimus dorsi as one of the flaps mandates a two-stage flap transfer.

Conflict of Interest

None declared.

• References

• 1 Kang MJ, Chung CH, Chang YJ, Kim KH. Reconstruction of the lower extremity using free flaps. Arch Plast Surg 2013; 40 (05) 575-583
• 2 Haykal S, Roy M, Patel A. Meta-analysis of timing for microsurgical free-flap reconstruction for lower limb injury: evaluation of the Godina principles. J Reconstr Microsurg 2018; 34 (04) 277-292
• 3 Serra JM, Ballesteros A, Paloma V, Mesa F. Simultaneous reconstruction of both feet with a vascularized latissimus dorsi free flap. J Reconstr Microsurg 1990; 6 (04) 353-356
• 4 Khouri RK, Upton J. Bilateral lower limb salvage with free flaps in a patient with sickle cell ulcers. Ann Plast Surg 1991; 27 (06) 574-576
• 5 Pribaz JJ, Morris DJ, Barrall D, Eriksson E. Double fillet of foot free flaps for emergency leg and hand coverage with ultimate great toe to thumb transfer. Plast Reconstr Surg 1993; 91 (06) 1151-1153
• 6 Cipriani R, Contedini F, Greco F. et al. Repair of bilateral lower limb injuries using a free latissimus dorsi cross-leg flap. Eur J Plast Surg 1999; 22: 147-151
• 7 Whitney TM, Buncke HJ, Lineaweaver WC, Alpert BS. Reconstruction of the upper extremity with multiple microvascular transplants: analysis of method, cost, and complications. Ann Plast Surg 1989; 23 (05) 396-400
• 8 Safak T, Akyürek M. Creating two independent fasciocutaneous free flaps from a single radial forearm donor site. Ann Plast Surg 2001; 47 (03) 247-251
• 9 Chiang YC, Wei FC. Simultaneous coverage of two separate defects with two free hemiflaps harvested from one latissimus dorsi muscle. Plast Reconstr Surg 1995; 95 (02) 385-389
• 10 Chen HC, El-Gammal TA, Chen HH, Wei FC, Lin CH, Tang YB. Economy of donor site incisions: multiple free flaps of the subscapular family for extensive extremity wounds and bilateral foot defects. Ann Plast Surg 1998; 41 (01) 28-35
• 11 Hong JP, Kim EK, Kim H, Shin HW, Hwang CH, Lee MY. Alternative regional flaps when anterolateral thigh flap perforator is not feasible. J Hand Microsurg 2010; 2 (02) 51-57
• 12 Wei CY, Chuang DC, Chen HC, Lin CH, Wong SS, Wei FC. The versatility of free rectus femoris muscle flap: an alternative flap. Microsurgery 1995; 16 (10) 698-703
• 13 Daigeler A, Dodic T, Awiszus F, Schneider W, Fansa H. Donor-site morbidity of the pedicled rectus femoris muscle flap. Plast Reconstr Surg 2005; 115 (03) 786-792
• 14 Gardetto A, Raschner Ch, Schoeller T, Pavelka ML, Wechselberger G. Rectus femoris muscle flap donor-site morbidity. Br J Plast Surg 2005; 58 (02) 175-182
• 15 Wong CH, Ong YS, Wei FC. The anterolateral thigh: vastus lateralis conjoint flap for complex defects of the lower limb. J Plast Reconstr Aesthet Surg 2012; 65 (02) 235-239
• 16 Lin CH, Wei FC, Lin YT, Yeh JT, Rodriguez EdeJ, Chen CT. Lateral circumflex femoral artery system: warehouse for functional composite free-tissue reconstruction of the lower leg. J Trauma 2006; 60 (05) 1032-1036
• 17 Laporta R, Atzeni M, Longo B, Santanelli di Pompeo F. Double free fillet foot flap: sole of foot and dorsalis pedis in severe bilateral lower extremity trauma, a 10-year follow-up case report. Case Reports Plast Surg Hand Surg 2016; 3 (01) 62-65

Publication History

Article published online:
01 October 2024