ABSTRACT
In a prospective study, the recovery of mechanical sensibility in five free flaps
transferred to the foot was assessed qualitatively and measured with a quantitative
method. The detection thresholds for 20, 80, and 240 Hz vibration frequencies were
determined preoperatively from the recipient area and post-operatively from the flap
at intervals of two to six months up to 14 to 21 months. Detection thresholds to mechanical
vibration could be measured in the flaps immediately after operation before any sensory
innervation could have taken place. The immediate postoperative thresholds were similar
to the preoperative values obtained from an existing full-thickness defect; and where
surgery had created a considerably deeper defect, they were elevated. The recovery
of mechanical sensibility in the transferred flaps was found to be slow and incomplete.
In three patients, after one year of follow-up, the flaps showed qualitative improvement
in sensibility accompanied by a moderate lowering of detection thresholds obtained
with 240 Hz vibration frequency. In two other flaps, there was no improvement in sensibility.
In the reconstructions that had good soft-tissue stability, the flap was resistant
to breakdown even before sensory recovery.
