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The skin covering the head and neck region is unique and its characteristic varies greatly depending on its anatomical location. The skin of the scalp is the thickest skin in the body and has a high density of hair follicles; this skin is not found anywhere else in the human being. It serves a protective function by enveloping the skull and its hair has an aesthetic purpose. Conversely, the upper eyelid skin is the thinnest skin in the human. It is thin and light and is easily closed and opened by the eyelid muscles to protect the underlying eye through rapid, dynamic movements. The pigmentation of the skin also differs from region to region and is affected by one’s ethnicity and degree of sun exposure.
Surface defects of the head and neck region may arise from a multitude of possible causes. Causes include injury (accidents, burn etc), infection and most commonly, defects resulting from tumor resection surgery.
Surface defects of the head and neck may manifest in all different shapes, sizes and depths. Acute injuries often result in visible wounds whereas defects that have healed may manifest as a tight scar contracture that when released, unveils the extent of the tissue deficiency. Surface defects of the head and neck may expose critical underlying structures such as vital nerves, blood vessels and bone. Soft tissue coverage of these defects is important to maintain vitality of these structures, prevent bacterial infection from the external environment and to restore the facial form to facilitate social reintegration.
The important factors when contemplating reconstruction of surface defects include the size and location of the defect, the skin thickness and pigmentation. A variety of skin grafts and flaps may be used to resurface these defects optimally. Attaining attractive and functional results requires accurate assessment, precise technical execution and an experienced practitioner. Successful reconstruction may be attained in most cases; this restores form and function, improves self-confidence and social functioning.
Skin grafts possibly originated in India 3,000 years ago. It was a common practice then to punish thieves by amputating the tips of their noses. Medical practitioners would resurface these defects with skin grafts taken from the buttock region. The art and science of skin grafting has significantly improved since and skin grafts are simple and reliable procedures performed for resurfacing of defects in many cases.
Skin grafts are often used in the setting of burn injury, trauma (e.g. accidents or interpersonal violence) and tumor resection defects. Skin grafts may be harvested as split-thickness or full-thickness skin grafts. In the head and neck region, it is common to perform full thickness skin grafts as this minimizes graft contracture and produces better long-term results. Grafts are often harvested from the back of the ear, neck, upper chest or forearm to provide the best color and thickness match.
Skin grafts “heal” to the underlying wound bed within 1 to 2 weeks. During this interval, the blood vessels from the wound bed grow into the skin grafts and provide them with their permanent blood supply. Because of the necessity for ingrowth of blood vessels to sustain the tissue, skin grafts are always thin and are suitable for covering shallow defects.
Flaps are tissues that are harvested from a donor site and moved to a recipient site with its intact blood supply. This permits the harvest of thicker pieces of tissue, as well as tissue composites to resurface complex and deep defects. The principles of local flap reconstruction are:
Local and regional flaps are usually performed for small-to-medium sized defects in the head and neck. They may be harvested together with skin, fat, muscle, bone and/or cartilage to reconstruct a wide range of defects. These flaps may be moved into the defect by direct advancement, rotation or transposition. Regional flaps may be harvested from the scalp, neck or chest to reconstruct large composite defects of the facial skin and skeleton including the jaws. Flaps heal to the adjacent wound bed within 1 to 2 weeks.
Distant flaps are flaps that are harvested from a donor site that is anatomically remote from the recipient site with its intact blood vessels. Similar to local and regional flaps, distant flaps harvest thicker pieces of tissue, and may also include skin, fat, muscle, bone and/or cartilage to perform a like-for-like reconstruction in the head and neck.
Distant flaps are normally used where no local or regional tissue is available, or where the wound defects are large and complex. This may include harvesting flaps from the back and the upper and lower extremities. Following flap harvest, the blood vessels that supply the flap will need to be connected to blood vessels in the vicinity of the defect using microsurgical techniques, where ultra-fine sutures that are thinner than a strand of hair are used. Microsurgery is a niche surgical technique that is technically demanding technique that requires intensive training over many years. Successful outcomes are possible in the vast majority of cases and require careful preoperative planning, precise technical execution and an experienced practitioner.
The head and neck region is a complex and intricate one that serves critical physical, emotional, social and psychological functions. Reconstruction of this region requires restoration of both function and aesthetic and necessitates experienced and skilled practitioners. Dr Yeo has a keen clinical interest in this area and has been at the forefront of delivery of this care. He completed a fellowship in Advanced Reconstructive Microsurgery as an international fellow under the illustrious Professor Hung-Chi Chen, one of the global leaders for such surgeries. Dr Chen is also one of the leading international authorities in intestinal flap reconstruction of the head and neck region and Dr Yeo is pleased to have performed the first successful case of colon flap reconstruction of the pharynx in Singapore.