Safety of clinical overinflation of tissue expanders

Despite adherence to a rigorous methodology with precise preexpansion calculations that culminate in the selection of an appropriate implant, the predicted surface area gain after completion of tissue expansion often falls short of the clinical requirements. Rather than then resorting to serial expansions, cutaneous overexpansion usually can be achieved to reach the desired dimensions by overinflation of the implant even well beyond the vendor's stated maximum volume. Over the past decade in a series of 69 patients using 97 tissue expanders, some degree of overexpansion was utilized in 53 implants (54.6 percent). No adverse sequelae due to mechanical failure specifically attributable to this hyperinflation occurred. Complications in the overinflation group (18.9 percent) actually were significantly fewer than those observed in the underexpanded (41.9 percent) (p < 0.03) but were similar in classification. Rather than any inherent superiority in the former group, this observation probably more accurately reflects the fact that overexpansion rarely could be done practically after a significant complication. In any event, the proven safety of limited clinical overexpansion allows a margin of error in the initial choice of implant volume and later permits continued expansion if more tissue than originally anticipated is needed.