Plastic surgery may not come to mind intuitively when thinking of cancer patients. However, plastic surgery plays an important role in restoration of anatomy, function and cosmesis for many of our patients who have lost them due to cancer invasion or, more frequently, the radical treatment required for the cancer. The defect may be as simple as a small skin and subcutaneous defect after excision of a basal cell carcinoma, to something as complex as total maxillectomy-mandibulectomy defect after resection of an extensive buccal carcinoma.
Before discussing reconstruction, resection defects can be optimized by respecting skin tension lines and aesthetic units wherever possible, with the caveat that surgical clearance must not be compromised. Where there is a conflict of resection versus ease of reconstruction, resection must take precedence.
The principles of plastic reconstruction are:
- restoration of function,
- restoration of anatomy with similar tissue wherever possible e.g. bone with bone, skin with skin,
- simple preferred to complex,
- low donor site morbidity,
To achieve these aims, there is a hierarchy of methods, from simple to complex, beginning with primary closure, local flaps, free grafts, regional flaps, distant flaps and free flaps.
Primary closure is the technique of choice in small wounds, where closure may be achieved with no tension. This results in the best outcome. Undermining of surrounding subcutaneous tissue may be necessary to relieve tension. Closure may be facilitated by modification of the wound with Z-plasty, W-plasty, V-Y plasty etc. These allow re-orientation of the whole wound or segments of the wound to allow tension free closure and to break the line of the scar for a better cosmetic outcome.
Where primary closure cannot be achieved, the next best option is local flaps. These include simple advancement flaps, transposition flaps and rotation flaps. Tissue match is usually good as these flaps are typically from adjacent tissue. Donor site morbidity is minimal, although a long incision may be necessary in tissues with little compliance e.g. the scalp. An example of a transposition flap is the nasolabial flap for reconstruction of a nasal defect after excision of basal cell carcinoma.
Free grafts may be used in areas where cosmesis is not critical or if there is insufficient local tissue for local flaps. They range from thin split skin grafts, full thickness skin grafts to complex composite grafts including cartilage etc. As grafts are not vascularised, survival of grafts are dependent on the vascularity of the recipient bed, thickness of graft (thinner better) and stability (shearing leads to devascularisation).
Consideration should also be given to the donor site, for tissue match and donor site morbidity. Split skin grafts tend to result in poorer cosmesis, especially if meshed to increase area. However, they take more easily as they are thin and can be used for extensive skin defects. The donor site typically heals with hyper or hypo-pigmentation. Full thickness skin grafts result in better cosmesis, but their thickness limits their size and decreases take rate. The donor site is closed primarily, usually with good results. Composite grafts have an even poorer survival rate due to complexity and poor vascularity. An example is a full thickness conchal (ear) graft for nasal alar reconstruction.
A large or complex defect after resection typically requires either a sizeable regional flap or free flap reconstruction. The choice is dictated by the patient’s fitness to tolerate prolonged surgery, the nature of the defect, whether it requires distant tissue egg bone for the mandible. Occasionally, compromises have to be made in an unfit patient. For instance, when reconstructing a commando defect, a pectoralis major flap may be chosen to reduce surgical time and to ensure greater flap survival instead of a free fibular flap, which is ideal in a fitter patient.
Regional flaps may be composed of a combination of different tissues. Forehead flaps and deltopectoral flaps are examples of fasciocutaneous flaps. Pectoralis major and latissimus dorsi flaps are myocutaneous flaps. These are transferred based on their blood supply, with the pedicle still attached after the transfer. The advantage is shorter surgical time and a lower risk of flap failure, as the native vascular pedicle is less prone to problems like thrombosis, compared to free flaps, which require microvascular anastomosis. The flip side of having an attached pedicle is limitation of range. Thus a pectoralis major flap is unable to reach a defect over the forehead or scalp.
Before the advent of the operating microscope and expertise for microvascular anastomosis, flaps were sequentially “walked” to from the donor site to the recipient site, or if it came from a mobile appendage like the forearm, the limb had to be kept close to the recipient site until the flap had revascularised from the bed before the pedicle could be detached. This era of microvascular free flap has revolutionized our ability to reconstruct complex defects with like for like. An example is the use of a free fibular flap after commando resection, where the fibula replaces the resected mandible and skin is used to cover the mucosal defect.
With our current repertoire of plastic reconstructive techniques, almost any defect can be covered. However, a well-designed prosthesis may occasionally yield better cosmetic and functional outcomes than the most technically flawless flap. It takes wisdom and experience not to view everything as a nail when you have a hammer in hand.
Dr
Tay Hin Ngan
Registrar
Dept of Surgery
Singapore General Hospital
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