Reconstructive Head & Neck Surgery
Introduction and Basic Principles:
The head and neck present a particular reconstructive challenge, not only due to the intricacy and diversity of structures within the region, but also because the face is intimately associated with individual identity. Facial cosmesis tends to be of paramount importance to many patients. Furthermore, the need to achieve functional outcomes in terms of speech and swallowing adds an additional layer of complexity to the equation.
A variety of techniques are available for reconstruction of the head and neck, depending on the size and location of the defect to be repaired. The concept of the reconstructive ladder was formulated to help guide selection of treatment options . Reconstructive procedures are organized in order of complexity, with the simplest approaches generally having fewer risks and complications but also less adaptability and functional capacity. Consideration of treatment options typically begins at the bottom of the ladder and progresses upward in complexity as needed. An informed decision regarding surgical approach must take into account many factors, including composition of the defect (e.g., mucosal, soft tissue, bony), neurovascular supply of the region, whether the area has been or will be irradiated, whether sensory or motor function needs to be restored, and general patient health and nutritional status. Patients with head and neck malignancies are frequently elderly, have comorbid conditions, use tobacco, or have difficulty eating—all of which may negatively impact wound healing and reconstructive outcome.
Healing by Secondary Intention:
Allowing the wound to granulate in is the simplest option on the reconstructive ladder. Healing by secondary intention produces good results for small defects of the medial canthus and lateral forehead.
Primary defect closure is the next simplest option; however, its use is often precluded by large defect size. Primary closure can lead to development of wound contracture. If this is the case, scar revision using a local flap or z-plasty may be done to improve appearance.
Skin grafts may be used to cover relatively small defects of the face, scalp, ear, and oral cavity. Skin grafts may be split thickness (STSG) or full thickness (FTSG). Split thickness skin grafts include the epidermis and a variable portion of the dermis. Full thickness skin grafts contain the epidermis and the entire thickness of the dermis. Common donor sites for STSGs include the abdomen, thigh, and buttock. FTSGs can be taken from the postauricular area, upper eyelid, supraclavicular region, or groin. FTSGs have the benefit of being more similar to native tissue in color and texture, providing better cosmesis. However, they do not take as well as STSGs.
Skin grafts do not have their own blood supply and are vascularized by the underlying tissue they are grafted upon. Therefore, the risk of graft failure is increased in areas of scarring, infection, or irradiated tissue. Additionally, skin grafts adhere best to fat, muscle, fascia, or perichondrium. Graft take is poor over bone or meninges. Placement of STSG directly over hardware is contraindicated without the presence of vascularized tissue in between.
Compared to skin grafting, local flaps can provide superior cosmetic appearance due to better color and texture matching. Many types of local flaps exist, such as advancement flaps, rotation flaps, and transposition flaps. The nasolabial flap is commonly used for nose or lip reconstruction. Most local flaps are based on unnamed subdermal vascular plexuses ; creation of such flaps must generally obey certain length-to-width ratio requirements to ensure adequate perfusion. Thus, use of local flaps is restricted by defect size, as well as distance from defect to suitable donor site.
The vascular supply of a pedicled (regional) flap is based on an identifiable vessel; the flap can therefore be transposed as far as the length of the pedicle. Pedicled flaps may be fasciocutaneous or myocutaneous. Common pedicled flaps include the paramedian forehead flap (often used in nasal reconstruction), temporalis flap, pectoralis major flap, latissimus dorsi flap, and trapezius flap. The pectoralis major flap may be used to fill oral cavity or pharyngeal defects by transferring the flap superiorly through the neck. A more detailed discussion of this flap can be found in Pectoralis Major Myocutaneous Pedicled Flap. Limitations of pedicled flaps include length and orientation of the vascular pedicle and potential donor site morbidity. Myocutaneous pedicled flaps may also be bulky, particularly if the muscle is harvested with an overlying skin paddle attached.
Microvascular Free Flaps:
Microvascular free tissue transfer involves harvesting the vascular supply of the donor flap, insetting the flap into the defect, and reanastomosing the vascular pedicle to arteries and veins in the region of the defect. Neural anastomosis is also possible, allowing for the potential to restore some sensory capacity to the area of defect. This technique provides maximal flexibility, given that there is no restriction on distance between the donor site and the defect. Free flaps are also subject to fewer rotational or geometric constraints than pedicled flaps. Large defects can be filled, as can defects consisting of multiple tissue types. Importantly for head and neck surgery, free flaps can contain osseous components. This feature makes microvascular free tissue transfer the primary reconstructive method for many cases of composite resection of the oral cavity, where segmental mandibulectomy has been performed. Osteocutaneous flaps can be harvested from the fibula, scapula, and iliac crest. The fibular free flap is the preferred flap for mandibular reconstruction, due to low donor site morbidity and the similarity in caliber between the fibula and mandible. Additionally, the fibula allows for the placement of dental implants. The fibular free flap is based on the peroneal vessels. The anterolateral thigh and radial forearm are other regions where free flaps are commonly harvested for use in the head and neck.
Drawbacks to microvascular free flap reconstruction include a 3-5% risk of flap failure due to vascular clotting, donor site morbidity, and increased duration of surgery. The vascular pedicle anastomosis is prone to vascular congestion, kinking, or clotting, resulting in flap ischemia. The flap therefore requires careful, frequent monitoring in the immediate postoperative period. Patient recovery is longer for free flap procedures than pedicled flaps, and patients spend longer in the operating room under general anesthesia. Appropriate patient selection is critical to the success of free flap reconstruction.
- A simple reconstructive ladder includes healing by secondary intention → primary closure → skin grafting → local flaps → regional/pedicled flaps → microvascular free tissue transfer.
- Skin grafts do not have their own blood supply and rely on the underlying tissue for vascularization; they do not take well over bone, meninges, or hardware.
- Local flaps include advancement, rotation, transposition, and tube flaps; most are based on unnamed subdermal plexuses.
- Pedicled flaps may be fasciocutaneous or myocutaneous and are based on identifiable vessels.
- Microvascular free flaps can contain multiple tissue types, including bone; they are performed by harvesting the vascular supply of the donor flap and reanastomosing it to vessels in the region of the defect.
- Free flaps have a higher risk of flap failure due to anastomotic failure resulting in ischemia and require close, frequent monitoring during the postoperative period.