Increased sensitivity in objective monitoring of tissue expansion

The end point for incremental filling of any tissue expander normally may reliably be assessed using subjective parameters, especially pain, as a guideline. However, in unusual circumstances, such as within denervated areas, the presence of marginal skin circulation, or if rapid expansion is required, an objective monitor may be beneficial to ensure safer expansion. We have previously examined the role of serial measurement of transcutaneous oxygen in this regard. In an effort to refine this sometimes cumbersome approach, a comparison using laser Doppler flowmetry as well has been undertaken in 13 consecutive patients. Both monitoring devices demonstrated a progressive impediment to blood flow with increased expansion. At the pain threshold, both techniques recorded values consistent with adequate skin circulation, thereby proving in general the relative safety of subjective evaluation during the usual course of tissue expansion. Greater sensitivity was noted for the laser Doppler as a monitor, though, via the recording of earlier changes in flow characteristics and more rapid identification of critical thresholds for nonviability. From a more practical standpoint, immediate application without a period for equilibration is another major asset of laser Doppler flowmetry as a system for objective monitoring.