Free tissue reconstruction

Abstract

Reconstruction of the Achilles tendon in the face of skin deficiency is a difficult surgical dilemma. Acute rupture with extensive local soft tissue trauma, as well as chronic rupture with or without associated infection, requires a more sophisticated reconstruction. The reconstructive algorithm for an Achilles tendon rupture is well documented in the literature. Small segmental tendon defects, less than 2 cm without soft tissue trauma, can usually be primarily repaired with good success. Larger tendon defects have been successfully reconstructed with V-Y tendon flaps, gastrocnemius turn-down flaps, fascia lata grafts, Marlex mesh, and flexor hallucis longus interposition grafts. All of these repairs rely on the presence of an adequate soft tissue envelope to allow wound closure, which is critical for proper tendon excursion, protection of the tendon from desiccation, and durability during ambulation. In the face of significant soft tissue loss associated with an Achilles tendon injury, such methods are unable to provide a functional Achilles tendon restoration. Absence of an adequate soft tissue envelope adjacent to the Achilles tendon can result from trauma, but can also occur due to complications associated with patient comorbidities, such as diabetes. Acute ruptures that are primarily repaired may become infected, resulting in significant soft tissue loss after debridement with exposure of the Achilles tendon. Likewise a recurrent rupture of a previously repaired Achilles tendon can compromise the soft tissue envelope, preventing wound closure over a subsequent tendon repair. In addition, patient comorbidities such as diabetes, venous insufficiency, and peripheral vascular disease can often lead to poor wound healing, incisional dehiscence, and exposure of the Achilles tendon. Poor wound healing usually requires the transplantation of well-vascularized soft tissue to adequately protect the Achilles tendon repair. Due to the lack of adequate adjacent tissue available, such as a local flap, reconstruction of both the tendon and soft tissue requires a more sophisticated repair. Complex Achilles tendon injuries include two elements that need to be reconstructed. There is a need to repair the tendon or provide a suitable graft to restore functional continuity. In addition to tendon repair, there is a need for skin and soft tissue to create an adequate environment for tendon excursion. The goals of complex Achilles tendon reconstruction, therefore, may demand a composite reconstruction of both of these components. Although one or both of these elements may be reconstructed using individual components, such as a Marlex mesh or tensor fascia lata graft for tendon continuity followed by soft tissue transposition for coverage, the ability to perform free tissue transfer through microsurgical techniques allows for a single-stage composite flap reconstruction. Free tissue transfer through microsurgical techniques has advanced the state of Achilles reconstruction. Since the first reported cases of tissue transfer for lower extremity reconstruction in the 1970s, significant advances have been made in the understanding of the microvascular architecture of free flaps. This is due in large part to Taylor's work to define angiosomes. The description of composite flaps that contain different tissue components enables reconstructive surgeons to adhere to Sir Harold Gillie's principle of replacing "like with like." Free tissue transfer allows the surgeon to transplant tendon, fascia, skin, soft tissue, muscle, and bone all within a single vascularized unit or composite flap. The use of vascularized tissue through microsurgical techniques has been documented to decrease the rate of wound infections, and improve wound healing. The thickness of a flap can also be selected, allowing for better contour and cosmetic appeal. Resurfacing of the Achilles tendon requires thin flaps that are durable and allow for normal shoe wear. © Springer Science+Business Media, LLC 2009.