Secondary Microvascular Reconstruction of the Traumatic Facial Injury

Background

The preoperative planning and technical execution of craniofacial microsurgical reconstruction following traumatic injury is inherently complex. Patients may present with injury to any combination of tissue layers – including skin, vasculature, muscle, nerves, and bone – and reconstructive options span the entirety of the microsurgeon's armamentarium. These challenges are compounded in secondary reconstruction as prior reconstructive efforts may limit the surgical options available. Primary reconstruction often reduces the number of available recipient vessels and donor sites, while local tissue damaged by scarring and multiple operative attempts is more difficult to manipulate and more prone to complications, including necrosis and flap loss. An overly ambitious primary reconstruction may require an unplanned return to the operating room for secondary repair, which limits surgical options and reduces patient trust. However, when part of a pre-planned, multistaged surgical solution, secondary reconstruction can yield better functional and aesthetic outcomes than a single-stage operation.

Rodriguez et al. have previously described their approach to complex craniofacial reconstruction, which aims to optimize both functional and aesthetic outcomes. In summary:

1.
Aesthetic unit: the integrity of the aesthetic unit depends not only on soft tissue volume but also on adequate structural support.
2.
Defect boundaries: when greater than 60% of an aesthetic unit is compromised, achieving an optimal result requires extending the defect boundaries to include the entire aesthetic unit so as to minimize scar burden and create unit homogeneity.
3.
Tissue requirements: donor site selection must consider specific tissue deficiencies, including skin, mucosa, fat, muscle, and bone, as well as color match and volume requirements.
4.
Bone and soft tissue support: deficient skeletal buttresses must be reconstructed with vascularized bone so as to provide adequate long-term support to the overlying soft tissues.
5.
Soft tissue volume: the volume of soft tissue included in the reconstruction should be in slight excess of the base volume of the defect and should be vascularized so as to minimize resorption with the understanding that subsequent soft tissue contouring is preferable to additional tissue transfers.
6.
Timing: early reconstruction minimizes morbidity by condensing the periods of healing from the initial injury and from the reconstruction into one event.
7.
Secondary revisions: planned multistage reconstructions utilizing distant flaps for support and coverage followed by local flaps for color and contour improvement are preferable to unplanned secondary operations necessitated by complications or inadequate primary reconstruction.

All of these principles can help guide surgical decision-making when approaching the traumatic facial injury. However, the last two points – timing and secondary revisions – are particularly relevant to secondary microvascular reconstruction and will be discussed more extensively, along with the principle of tissue requirements.

Surgical Anatomy

A wide variety of free flap options exist for the secondary reconstruction of traumatic defects of the face. The advantages and disadvantages of common donor sites are summarized briefly below.

Ulnar Artery Perforator Flap

First described by Lovie et al. in 1984, the ulnar artery perforator flap provides thin, pliable tissue with a long pedicle, the ascending branch of the dorsal cutaneous branch of the ulnar artery. The donor site is less morbid than the neighboring radial forearm flap, and the skin of the ulnar forearm flap is less hirsute than its radial counterpart, making the former better suited for coverage of non-hair-bearing areas. The thinness of the flap precludes it from use in covering defects requiring bulky soft tissue or involving hardware, which can be exposed as the denervated flap thins over time. Acceptance of the ulnar artery perforator flap by the microsurgical community has been sluggish owing to concerns over potential compromise to hand perfusion and innervation, despite long-term outcome analyses failing to demonstrate significant motor, sensory, or vascular impairment associated with ulnar forearm flap harvest.

Anterolateral Thigh Flap

Since its introduction by Song et al. in 1984, the anterolateral thigh flap (ALT) has become widely accepted as a workhorse flap for head and neck reconstruction. Its versatility in size and soft tissue components, reliable anatomy based off of the lateral circumflex femoral artery, and relative ease of harvest make the ALT a popular choice for the reconstruction of a wide range of head and neck defects. Disadvantages of the flap include its tendency – particularly in obese patient populations – to be especially bulky, its susceptibility to atrophy when muscle is included, and its potential to be hair-bearing.

Groin Flap

The groin flap, based off the superficial circumflex iliac artery, holds historical significance as the first successful free flap. Advantages of the flap include its ability to be designed with muscle or as a perforator flap of variable depth and its easily concealed donor site with minimal morbidity. However, the utility of the groin flap is limited by its relatively short pedicle length and somewhat variable anatomic course.

Iliac Flap

First described by Acland in 1979, the iliac flap provides substantial bone, muscle, soft tissue, and skin fed by the deep circumflex iliac artery (DCIA) and can be used for the reconstruction of extensive defects involving multiple tissue layers. The natural curvature of the iliac can approximate the angle of the mandible for jaw reconstruction, and the presence of vascularized bone provides the long-term bony support required for osseointegrated implants. Despite these advantages, its use as a vascularized bone flap has decreased with the advent of the free fibula flap owing to the iliac flap's higher donor site morbidity and shorter pedicle length. In cases where fibula-based reconstruction is not an option the iliac flap is a viable reconstructive modality for osseous or myo-osseous defects.

Free Fibula Flap

The free fibula flap (FFF), first described by Taylor for use in lower extremity salvage and then by Hidalgo for mandibular reconstruction, is one of the most commonly used vascularized osseous and osseocutaneous flaps. Its advantages include a substantial quantity of high-quality bone stock, its ability to include a wide range of tissues, and its flexibility in maneuvering those tissues without compromising blood supply. Disadvantages include variability in the pedicle length depending on the length of fibula being harvested and the potential for donor site morbidity including compromised ankle function, leg weakness, and great toe contracture.

Clinical Presentation

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here