Flow-through flaps: A review of current knowledge and a novel classification system

Abstract

Flaps have long been recognized as an essential tool for soft-tissue reconstruction. Flaps range in complexity from local to free and perforator flaps and can include a variety of composite tissues. The concept of a flow-through flap, in which both the proximal and the distal ends of the vascular pedicle of a free flap are anastamosed to provide blood flow to distal tissues, was first described by Soutar et al. in 1983. An uninterrupted arterial flow was established by Soutar et al. between the external carotid and distal facial artery via a radial forearm flap for head and neck reconstruction (Soutar et al., Br J Plast Surg 1983;36:1-8). Shortly thereafter, Foucher et al. were the first to report the reconstruction of an extremity with a simultaneous vascular defect by utilizing a radial forearm flow-through flap (Foucher et al., Br J Plast Surg 1984;37:139-148). The utility of the flow-through flap is now well established, and its indications for use continue to grow. The principle advantage of this flap is that it provides the opportunity for a single stage composite reconstruction of both soft tissue and vascular defects, making it particularly useful in the reconstruction of ischemic extremities and defects from oncologic ablations. Improvements in microsurgical equipment and techniques are making early difficulties with these flaps irrelevant, giving plastic surgeons opportunities to become more creative in the choices and uses of flow-through flaps. The literature consists mostly of case reports and series. The nomenclature used to describe the types of flow-through flaps is confusing and inconsistent. The purpose of this article is to provide an organized review of flow-through flaps and to classify these flaps based on their inflow, outflow, and the nature of their vascular conduit. Additionally, we have included a discussion on the physiology of these flaps, reviewed the current literature, and summarized the various types of flow-through flaps in a reference guide that can aid in flap selection.

Muscle Flaps and their Role in Limb Salvage

“…The radial artery flow-through flap provides a thin skin island and is well suited for defects of the foot and ankle region (Figure 2). 7 An additional benefit of the flow-through flaps is their positive influence on bypass graft flow. Anastomosis of a free flap to a distal bypass produces a decrease in distal resistance, thereby increasing flow.…”

Flow-through Free Latissimus Dorsi Flap for Reconstruction of Injured Limbs

“…Latissimus dorsi muscle especially has suitable vessel anatomy for this purpose because it provides an ample amount of well-vascularized tissue for extensive defects of severely damaged extremities. 3 In this report, we present 2 cases with major lower extremity injuries which were successfully treated with flow-through free latissimus dorsi flaps. This design of latissimus dorsi muscle flap provided continuity of the recipient artery and vascular supply to the flap, which are advantageous for repair of vascular injured extremity.…”

“…The characteristic triphasic Doppler signal of end organ shows a fast upstroke to peak systole (1), positive of blood flow during early diastole(2), and a forward flow component during late diastole(3).…”

Artery–Vein–Artery Venous Flap for Simultaneous Soft-Tissue Repair and Radial Artery Reconstruction: Case Report

“…Potential free flaps that can replace the thin tissue in this area include the dorsalis pedis and radial forearm flaps; however, these flaps are associated with loss of a major artery and morbid donor sites. 1,2 Although standard flaps, such as those created from the latissimus muscle or anterolateral thigh, can provide cover, 2,3 in our experience they are bulky relative to the tissues of the forearm and can potentially compromise both the aesthetic and the functional outcomes.…”