Monitoring of free tissue transfer is essential in the early post-operative period for attempts to salvage compromised flaps. Numerous non-invasive techniques are available for monitoring tissue viability including; clinical observation, hand-held doppler, surface temperature probes, implantable venous doppler, and color duplex. Evaluation of recipient vessels and identification of perforators are important for thorough pre-operative planning. Visualization of recipient vessels is crucial in previously irradiated or operated sites. Commonly used non-invasive methods for assessment of recipient vessels and perforators have been limited to duplex examination with large ultrasound units. Traditional duplex machines are not readily available because they are difficult to transport and have to be operated by vascular technicians.

With the advent of high-resolution hand-held ultrasound units, we sought to evaluate the efficacy of a portable device for pre-operative and post-operative assessment of free flap vasculature. We used SonoSite 180 ^TM with a 5-10MHz linear transducer. This transducer can visualize structures to a depth of 7 cm. This unit can color code blood flow and measure the vascular diameter with 0.1 mm accuracy. Fluid collections are easily identified and distinguished from vascular structures.

We examined a total of thirteen patients. Five patients were evaluated pre-operatively. Four patients underwent free TRAM procedures. Dominant flap perforators, size and location of recipient vessels were visualized. The findings correlated closely with intra-operative observations. One patient had free parascapular flap transfer for facial asymmetry. The superficial temporal vessels were identified in spite of multiple previous surgeries and scarring in the preauricular region. Ten patients were evaluated following free flap procedures. Vascular pedicles were visualized in all cases. We used the portable ultrasound in two patients to identify fluid collections and percutaneously drain them.

Among the non-invasive methods for monitoring and evaluation of free flaps the hand-held ultrasound machine is the most convenient, easy to use and versatile. Ultrasonic evaluation of recipient vessels and perforators is accurate and reproducible. Actual vessel size corresponded to the size predicted by imaging. Identification of perforators is helpful in designing flaps and pre-surgical planning. Use of the ultrasound for post-operative monitoring of free flaps yields more information than doppler as both artery and vein can be visualized. This technique is helpful in evaluation and treatment of fluid collections. The unit is readily available at any time of day and can be used by plastic surgery residents after a short training period.