Several techniques have been developed which do not fit readily into a neat classification, either because they are not strictly surgical, though they are used in a surgical context, or have been taken from other surgical disciplines because they offered a partial or complete solution to problems whose management by conventional plastic surgical methods was unsatisfactory.
TISSUE EXPANSIONIn this technique, a silastic ‘bag’, not unlike an uninflated balloon, is placed under the skin and superficial fascia, and inflated at intervals by the injection of saline under pressure. The saline is not injected directly into the ‘bag’, but into a small non-expansile reservoir placed at a distance from it, and connected to it by a fine bore tube.
In this technique, a silastic ‘bag’, not unlike an uninflated balloon, is placed under the skin and superficial fascia, and inflated at intervals by the injection of saline under pressure. The saline is not injected directly into the ‘bag’, but into a small non-expansile reservoir placed at a distance from it, and connected to it by a fine bore tube.
The effect of the inflation is to produce an increasing bulge of the overlying tissue, and in so doing stretch the skin. In this way the skin is ‘expanded’, increased in area, and made available for reconstruction. Expansion is exploited clinically in two ways.
In one, as used in postmastectomy breast recon-struction, the expanded skin and the underlying cavity are both utilised: the cavity for permanent insertion of a silicone implant to recreate the breast mound, the expanded skin to provide an envelope for the implant. . The other way in which the principle is used is in the creation of an area of skin availability which, sited alongside a defect, allows it to be closed directly.
The expanded area may be created beforehand, so that, when the defect is created, the expanded skin is already available to close it. Alternatively, it may be used to replace a skin graft, previously applied to cover the defect.
The skin adjoining a defect is generally re-cognised to give the best result in reconstructing it, because they have similar characteristics, and this is a major virtue of the method, one which shows most strikingly when it is used to extend hair-bearing scalp in replacing an area of alopecia. Various shapes of expanders are used -round, oval and crescentic -with different sizes, depending on the amount of expansion desired.
A skin incision is made, just long enough to allow the expander to be inserted without bending, and the pocket to accommodate it is dissected, generally at the deep level of the superficial fascia. A pocket is also made for the reservoir at a distance from the expander. 121 The reservoir is sometimes positioned externally, making injection easier as well as painless, though it probably increases the risk of infection reaching the expander.
A small volume of saline is injected immediately to smooth out the envelope of the expander, the incisions are closed, and the wounds left for 1-2 weeks to heal. Expansion is then begun, and repeated usually at weekly intervals. Whitening of the skin, indicative of local ischaemia, or a complaint of pain by the patient, are signs that expansion has gone far enough for the time being.
Over the period of the expansion, a degree of capsule formation usually builds up and, depending on its severity, it is left, scored or excised. The technique has its strong advocates, but overall it has not achieved the popularity which seemed likely when it was first introduced. Adverse factors concern the time taken to achieve adequate expansion, 6-12 weeks, and the increasingly bizarre appearance of the patient as expansion proceeds.
Even when circumstances are ideal, the complication rate is considerable, mainly the result of infection, haematoma or extrusion, and the nature of the technique means that any complication requires removal of the expander and spells failure of the method. The other substantial problem is that of designing the expansion, which involves three dimensions, to provide cover for a defect which, the breast and scalp apart, is usually two-dimensional. The most effective applications of the method have been where the surface is convex with a bony base, as in the scalp and forehead, and in breast reconstruction.