Following removal of a tumor or cancer from the sites of the head and neck, such as the tongue or the skin, there is a defect left which must be dealt with. The closure and healing of this wound site is referred to as reconstruction. There are a range of possible options for reconstruction of any particular defect, and pros and cons of each option are typically weighed. Sometimes there are clear preferences, and other times there are several different options which may be considered equally acceptable. Of course, usually only one option may be chosen, from the range of possibilities!
In weighing pros and cons, generally there is a preference to doing the simplest procedure as opposed to the more complex, when the end result is estimated to be equally acceptable. This concept is often referred to as the reconstructive ladder, where reconstruction options are ranked in terms of simple to complex: secondary intention healing, primary closure, skin graft, local advancement flap closure, pedicled flap, and free tissue transfer.
Secondary intention healing means the wound is left alone, and gradually heals with simple wound care and no further intervention. This is simple, and effective for many wounds. Best employed where cosmetic appearance is not critical, as some stellate scarring effect will result. Also best where the functional effect of scar bands forming is not detrimental. This option is employed for tonsillectomy wound sites in the oropharynx, laser excision wounds on the larynx, and small oral tongue wounds, as well as scalp skin wounds.
Primary closure is bringing the edges of skin around a wound together and suturing to hold them in close approximation. This is possible when the distance, and therefore the tension, on the tissue is not too great; if tension exists, the sutures will end up tearing and the tissue will gradually split back apart, leading to inflammation, infection, and a widened scar with not-ideal cosmesis. This is typically employed for sharply created surgical incisions through the skin, without significant skin tissue removal. To allow for primary closure, additional portions of skin around a planned excision are often removed (referred to as the standing cutaneous deformities) — which transforms many otherwise round wounds into elongated ellipses. By lengthening the wound and removing extra tissue that would otherwise bunch-up, primary closure is often possible, with less tension.
A skin graft is a thin portion of skin, consisting of just epidermis and dermis without any of the subcutaneous fat, which is harvested from a separate site, and placed as a free graft over a wound. It survives only by being held in close contact and with no mobility relative to the underlying tissue bed, which has to have a good blood supply and deliver nutrients to the skin graft by diffusion across the wound bed. Gradually, the skin graft becomes attached to the underlying tissue, with blood vessels and tissue connections established. This usually takes at least 10-14 days. This technique is relatively simple, and can be reliably effective. It results in a pale, shallow scarred appearance, which often retracts and tightens moderately, so best in a location where cosmesis is not critically important, and scarring is not detrimental.
Local advancement flap means additional incisions are creatively made around a wound and adjacent tissue is elevated and then advanced so that all wound edges are approximated well, so that skin edges can be closed with acceptable tension. It is a variation of primary closure, where the intention is to close skin and reposition the incisions to achieve the best possible scar appearance. There are numerous variations of local advancement flaps which have been applied to unique wounds on the head and face.
Pedicled flaps are full thickness portions of tissue (skin, subcutaneous fat, and variably underlying deep fascia/muscle/bone) which are elevated and remained attached to a defined blood vessel. The blood vessels (artery and vein) remaining attached to the tissue is absolutely essential for the survival of the tissue. The blood vessels are referred to as the pedicle. The pedicle can be as narrow as just the actual vessel, with no additional tissue, or additional tissue can remain with the pedicle, if needed to help carry or protect the blood vessels. The point of attachment (origin) of the pedicle blood vessels defines the rotation point of the flap, which limits the reach of this transfer of tissue. This is a powerful technique for reconstruction of moderately sized defects in the head and neck. A pedicled flap is very reliable, and often has desired characteristics of low donor site side effects and less complexity relative to free tissue transfer (discussed next). Examples of pedicled flaps commonly used in the head and neck include paramedian forehead flap, submental island flap, supraclavicular island flap, and pectoralis muscle flap.
The most complex end of the reconstructive ladder is the free tissue transfer. This is a full thickness portion of tissue (skin, subcutaneous fat, and variably underlying deep fascia/muscle/bone), which is elevated with dissection of a defined blood vessel (artery and vein), which are disconnected from their origin at some remote site of the body, and then transferred to the head and neck site. The tissue can be primarily sewn to the wound edges to accomplish the desired reconstruction, while the blood vessels must be attached to new blood vessel origins in the neck. These blood vessels are typically small (1.5 to 4mm), and the anastomosis is accomplished with microscope magnification using very small sutures or a mechanical coupling device. This technique is the most complex of reconstructive techniques, though is important and commonly employed, for moderate to large size defects. It is a necessary technique, in situations where all other reconstruction methods are ruled-out, due to size or location of the defect and likelihood of infection, fistula, poor healing, or poor return of function. The technique is dependent on the restoration of blood flow through the anastomosis of the small blood vessels. Formation of thrombus blocking blood flow in the vessel anastomosis is a risk, and the tissue is monitored carefully for the first week to ensure this does not occur; a 5% chance of flap failure is an often cited complication rate for this technique. Examples of commonly used flap flaps for the head and neck include: radial forearm, lateral arm, anterolateral thigh, fibula, and scapula system.
Kommentare