No abstract

Individual techniques for the postoperative monitoring of free flaps vary considerably. In order to establish the currently preferred protocols, a survey was conducted among micro-surgeons in North America using a mailed questionnaire. Data were received from 95 centers for the monitoring of 2,825 free flaps performed during 1994. Results indicate that rates for flap salvage and overall success with free tissue transfer are closely related to surgical experience (number of cases performed per month). Ninety percent of microsurgeons routinely use monitoring devices, with external and laser doppler having achieved greatest popularity. An account is given of the preferred postoperative regimens for flap surveillance, and the overall results are discussed.

Early recognition of vascular compromise within microvascular free-tissue transfers is essential if reexploration is to prove successful. Tissue oxygen tension is increasingly recognized to be a sensitive and reliable index of tissue perfusion, and preliminary studies suggest that it may be of value in the assessment of free-flap viability. We describe our investigation into the application of an implantable microcatheter oxygen sensor in the monitoring of free flaps used in head and neck and extremity reconstruction. In a preliminary study using the rabbit model, we sought to evaluate the response of oxygen tension as an index of tissue perfusion in myocutaneous (n = 20) and osteomyocutaneous flaps (n = 5) under conditions of arterial and venous occlusion. A clinical study was then undertaken to evaluate the role of this method in the monitoring of surface and buried free flaps. In 30 heterogeneous free-tissue transfers, sensors placed intraoperatively were used to provide continuous information about flap oxygen tension (mean monitoring period 3.2 +/- 0.8 days). The data generated were correlated with changes in clinical parameters and routine flap observations. Results for experimental and clinical data have confirmed the efficacy of continuous tissue oxygen measurements using this device as a method that provides an objective, recordable index of free-tissue transfer viability in a variety of circumstances and vascular events. Tissue oxygen tension is a suitable index by which to evaluate flap viability with the probe placed in muscle or bone but is unreliable when used for the monitoring of revascularized cutaneous flaps.