31 The Bulky Flap
31.1 Patient History Leading to the Specific Problem
A 38-year-old woman suffered a left upper extremity injury from motor vehicle collision. The skin was severely traumatized and much of the flexor mass was avulsed. The medial elbow joint was exposed. After debridement and thorough irrigation, the wound on the forearm and upper arm was extensive. The median nerve was intact but exposed. The flexor digitorum profundus muscle was intact. The proximal radius was fractured and temporarily fixated with an external fixator
31.2 Anatomic Description of the Patient’s Current Status
The traumatic injury to the patient’s left forearm required serial debridements of nonviable tissue prior to coverage. The debridement of skin, subcutaneous fat, and muscle (mostly flexor digitorum superficialis) created a defect with exposed vital structures including the median nerve and the medial elbow joint (▶Fig. 31.1). The tissue loss was largely volar, from the antecubital fossa to the volar wrist flexion crease, leaving the median nerve exposed lying on top of the flexor digitorum profundus muscle bellies. The anterior capsule of the elbow was avulsed, exposing the joint. An external fixator was needed for elbow joint stabilization, spanning from the distal humerus to the proximal radius. Soft-tissue coverage was required. The extent of the coverage mandated an enormous amount of tissue reconstruction.
31.2.1 Management of the Defect
Due to the large area requiring coverage, a fasciocutaneous free flap was selected for reconstruction. The flap needed to be very large, limiting the plausible choices for donor sites. An anterolateral thigh flap was chosen, providing satisfactory wound closure (▶Fig. 31.2). The flap was debulked three times over the ensuing 3 years to improve forearm contour.
31.2.2 Donor Site Problem
Inability to close the donor site primarily, due to the need for such a large flap to cover the forearm defect, necessitated split-thickness skin grafting to the right leg. This created a large contour deformity of the anterior thigh (▶Fig. 31.3). Other than a less-than-ideal aesthetic outcome, the nonpliable scar created discomfort for the patient during ambulation. The patient was not able to wear shorts without feeling self-conscious.
Fig. 31.3 The anterolateral thigh donor defect on the leg is unacceptable in patients with large body mass index.
Fig. 31.4 An 18-year-old girl sustained a mutilating injury to the forearm with fractures to the ulna and radius. There is massive extensor muscle loss.
31.3 Recommended Solution to the Problem
Management of a large soft-tissue defect of the forearm with exposed vital structures requires free tissue transfer. Local and regional pedicled flap options, such as a large pedicled abdominal flap, are not adequate for providing complete coverage or would require a two-stage approach. A fasciocutaneous free flap is a great option for such a defect. When considering the potential need for subsequent operations for functional improvements, that is, tendon transfers and tenolysis, a fasciocutaneous flap is easier to elevate than a muscle flap. The fascial component provides a “fresh” plane of dissection. Additionally, the cutaneous portion of the flap provides a more aesthetically pleasing reconstruction when compared to muscle free flap with a split-thickness skin graft.
The choice of fasciocutaneous flap should take the donor site into consideration. Given the vast array of different flaps available today, donor sites that leave disfiguring defects need to be avoided. We present next a similar forearm defect from a motor vehicle collision, although dorsal, in an 18-year-old female patient (▶Fig. 31.4). There is exposed hardware fixation of the radius and ulna after thorough debridement of the extensor muscle. The size and depth of the wound necessitate free tissue transfer, preferably with a fasciocutaneous flap for reasons mentioned previously. When executing any type of flap procedure, whether free or pedicled, primary closure of the donor site is ideal. There are not many other fasciocutaneous free flap options that are located in areas that usually have enough laxity to close as in the deep inferior epigastric artery perforator (DIEP) flap. This flap was used for forearm reconstruction in this patient.
31.3.1 Recommended Solution To The Problem
• Free tissue transfer needed for large surface area coverage.
• Fasciocutaneous flap is the best if additional reconstructive procedures are planned; it provides a more aesthetically pleasing reconstruction and it can be debulked.
• Choose flap where donor site can be closed primarily (i.e., DIEP flap).
Perforators to the skin can be identified with a Doppler preoperatively and marked on the skin. There is typically a lateral and medial row of cutaneous perforators that come off of the deep inferior epigastric artery. The flap’s dimensions and the decision to use a hemiflap versus the entire lower abdomen are dependent on the defect, as it is not difficult to close a donor defect spanning from 2 cm above the umbilicus to just cephalad to the pubis (▶Fig. 31.5a). Dissection is performed through skin and fat and down to the fascia. The flap is elevated off of the fascia in a lateral-to-medial direction. Perforators to the skin are identified and preserved. Once the perforators are chosen that are adequate to perfuse the flap, they are dissected down through the anterior rectus sheath and muscle to the pedicle. The deep inferior epigastric pedicle is traced back to its origin off of the external iliac vessels where it is ligated for flap removal (▶Fig. 31.5b). The superior abdominal flap is dissected off of the fascia to the costal margin and advanced inferiorly to meet the inferior skin for closure. The donor site is closed in layers with interrupted absorbable sutures in Scarpa’s fascia and the deep dermis, followed by an absorbable monofilament suture in the subcuticular layer.