Free-style puzzle flap as a cross-leg pedicled flap: the concept of re-using a flap in acute burns, a case report
In well-selected cases, flaps can play a pivotal role in optimizing outcomes in the acute phase of burns. A previous redundant flap could be reused or recycled as a donor site from which a new flap could be raised.
We report the case of a patient with full thickness burns on both legs, leading to the exposure of joints of the right ankle and the right foot and left patellar tendon. The right lower extremity was covered with a free musculo-cutaneous latissimus dorsi flap. Then, a musculo-cutaneous cross-leg flap pedicled on the anterior branch and centered on a perforator was harvested from the previous redundant flap to cover the controlateral knee.
Sequential flap coverage can be considered in cases of extensive soft tissue defects and particularly in burns. This case illustrates that re-using a redundant part of a previous flap to cover another defect is a safe and interesting alternative in the event of a lack of donor sites or to save donor sites for later reconstruction of contracted burn scars.
KeywordsBurns Free flap Pedicled flap Puzzle flap Cross-leg
The mainstay of operative treatment in burns remains as split thickness skin autografts. Platt et al. reported that skin grafts represent more than 95% of procedures in acute burns . Nevertheless, in well-selected cases, flaps can play a pivotal role in optimizing outcomes in the acute phase [2, 3, 4, 5, 6]. They allow the preservation of otherwise unsalvageable deep burns exposing joints, tendons, nerves or vessels. In cases of extensive soft tissue defects following the debridement of devitalized tissues, the surface or the location of the defects may exceed the possibility of coverage with a single flap. Havlik and Ariyan  reported cases of re-using a previous flap as a donor site. Mun  described a concept in which a previous redundant flap could be reused or recycled as a donor site from which a new flap could be raised. Feng et al.  called this concept a “free-style puzzle flap” and reported a series of oncologic and post-traumatic soft tissue defects covered with puzzle flaps.
Our aim in this article is to report the case of a patient in the acute phase of a burn requiring a free-style puzzle flap combined with a cross-leg pedicled flap.
In the majority of situations involving acute burns, a split thickness skin graft is the first option after debridement, as long as well-vascularized tissue remains. If the tissue left behind after excision is not suitable for a skin graft, local flaps are a second option. However, as the surrounding tissue may be involved in the zone of injury, local flaps are not always possible. As far as this patient was concerned, we concluded that a local flap, such as sural flap , could not cover the ankle and the foot because all the surrounding tissues were excised. Consequently, in such circumstances, free tissue transfer is the third option. Free flaps in burns are rarely indicated: in less than 2% of cases, including delayed post-burn reconstructions [1, 6].
We decided to perform a latissimus dorsi musculo-cutaneous flap. Whenever a large defect with dead space exists, a muscle flap is considered as a gold standard. The latissimus dorsi surface was large enough to cover the ankle and the foot. Moreover, the latissimus dorsi is a reliable flap with long pedicle and results in few sequelae at the donor site. A thoraco-dorsal artery perforator free flap was considered as a less safe alternative because of the hemodynamic instability of the patient and the possible use of vasopressive therapy. Indeed, the patient was treated with noradrenaline in order to maintain a stable blood pressure. This treatment is responsible for vasoconstriction of peripheral vessels including perforators. Consequently, we considered that a musculo-cutaneous flap, including more than one perforator would be safer and less sensitive to the effects of the treatment than a perforator flap based on a single perforator. The exposure of her left patellar tendon prompted us to perform a second flap. Local considerations were the same as the other limb for local flaps. An anterolateral thigh with a distal pedicle was discussed. However, the surface to cover were limited and donor sites for free tissue transfers are limited. Harvesting a second flap would have used another donor site for later reconstruction. Precisely in burns when some donor sites could be involved in the injuries.
The use of a previous redundant flap as a donor site is an interesting alternative in this situation [11, 12, 13, 14, 15, 16, 17]. Valauri et al.  reported the case of a patient who sustained bilateral below-knee amputations that were treated with skin grafts as initial coverage. A latissimus dorsi-free flap was later used as definitive coverage of one stump. During a subsequent operation, a portion of the same latissimus dorsi-free flap was harvested, again as a free flap, and transplanted to cover the contralateral stump. Thus, one latissimus dorsi-free flap was used twice as a free flap (free-flap free flap) to cover bilateral amputation stumps in sequential operations. Tan et al.  presented a case of a single free groin flap split in two to reconstruct two distant and separate defects sequentially. Chaput et al.  reported a case of puzzle flap in burns to cover the Achilles tendon after muscular retraction of the latissimus dorsi flap. The proposition advanced here was to combine the concepts of “puzzle flap” and “cross-leg flap” . To avoid tension on the vascular pedicle and to improve venous drainage, we decided to perform a musculo-cutaneous flap including the perforator instead of a propeller flap, which could also have been done. The use of the musculo-cutaneous flap was also a solution to debulk the anterior face of the ankle and to avoid traction on the vessels during the cross leg phase.
Sequential flap coverage may be considered in cases of extensive soft tissue defects, particularly in burns. With the advent of the concept of puzzle flap, reusing the monitoring part of a previous flap to cover another defect, in order to save donor sites for later reconstruction of contracted burn scars, is to be considered an interesting alternative. This innovative combination of a new concept (puzzle flap) and an old concept (cross leg) is an interesting example of the plasticity of flaps. Thanks to the great development of the identification of perforasomes, the surgeon would be able to recycle the skin paddle of a flap if perforators are found, which represents a second-line solution in the management of complex soft tissue defects.
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The authors declare that they have no competing interests.
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