Epigastric Island Flap Research Articles

Microsurgical application of freeze-dried arterial allografts.

Arterial allografts of 1.0 mm diameter and 1.0 cm length were freeze-dried and placed into the femoral arteries of 15 Sprague-Dawley albino male rats in order to study patency and tissue reactions of the host. Patency in the first three postoperative days was determined by monitoring viability of the epigastric island flap. All grafts were patent during this early postoperative period. Fourteen of the subjects were surgically explored after 2 months of observation. At that time, 13 (93%) remained patent. Histopathological studies, and transmission and scanning electron microscopy were used to analyze the specimens. These data demonstrated that freeze-dried arteries are remodeled by the host, but do not induce a cellular immune reaction. Dependable freeze-dried microarterial allografts have potential future application in clinical microvascular surgery.

Response of the rabbit cutaneous microcirculation to prostanoid modifiers as determined by laser doppler flowmetry

The cutaneous microvascular flow of the rabbit epigastric island flap under the influence of various prostanoid modifiers has been determined semiquantitatively with a Laser Doppler flowmeter. Infused prostacyclin, diluted with arterial blood to an estimated concentration of 2.5 ng/ml in the microvasculature, increased the microvascular blood flow to approximately 130% of the buffer control. The three thromboxane synthetase inhibitors tested—dazoxiben hydrochloride, UK-38,485, and 7-(1-imidazolyl) heptanoic acid—at concentrations up to 3 × 10 −5 M in the microvasculature, failed to induce any change in blood flow compared to a control neutral-buffered saline infusion. Preliminary results also found that the lipoxygenase inhibitor Bay g6575 did not alter microvascular flow up to 7 × 10 −6 M, but the prostacyclin analog carbacyclin at 30 ng/ml in the microvasculature induced a similar response to 2.5 ng/ml prostacyclin. While such responses are well known for the major vessels, this is one of the few reports with semiquantitative data on the influence of prostanoid synthesis modifiers on blood flow for the microcirculation.

An implanted ultrasound doppler probe for microvascular monitoring: an experimental study

An experimental investigation is presented into the use of pulsed ultrasound Doppler flowmetry with a percutaneously implanted probe as a monitor of microvascular anastomotic patency. The method accurately indicated and distinguished between experimental arterial and venous occlusion in epigastric island flaps. In free flaps it had advantages over manipulative, intra-operative tests of anastomotic patency and was a reliable post-operative monitor of flap circulation in the experimental model. The technique appears to have great potential as a post-operative monitor for free flaps, including those without a visible surface.

An Experimental Investigation into the Use of Implanted Thermocouples and Differential Thermometry as Monitors for Microvascular Anastomoses

It has been suggested that direct monitoring of arterial temperature using implanted thermocouples, may have value as a clinical postoperative monitor for vascularized free tissue transfers, including those with no visible surfaces. This study evaluated the technique in experimental animals, using simple, inexpensive equipment. Mean arterial differential temperature changes, with ipsilateral (n = 20) and contralateral (n = 21) references, of 0.6 degrees C and 0.5 degrees C respectively, reliably indicated occlusion of the superficial femoral artery in situ. In epigastric island flaps, arterial occlusion (n = 24) produced mean arterial temperature changes of 0.5 degrees C, but changes after venous occlusion were not significantly greater than unoccluded base line fluctuation. Venous differential temperature did not change significantly after either arterial or venous occlusion. In six epigastric free flaps, success or failure could not be distinguished, as the wide variation in measurements in the four successful flaps overlapped the recordings in the two which failed. It was shown that the nearer to the body core, the less the temperature difference between arterial wall and periarterial tissue. Occlusion of deeply sited arteries produced little or no change in arterial temperature. In view of these findings and because of the invasive nature of the technique, the authors did not pursue it clinically.

Microsurgical application of freeze-dried venous allografts.

Freeze-dried venous interposition allografts with an internal diameter of 1.0 mm and a length of 1.0 cm were placed into the femoral arteries of 17 Sprague-Dawley albino male rats in order to investigate patency and host tissue response. The immediate patency rate was 88%. The epigastric island flap was monitored as a sign of patency in the early postoperative period (defined as 1 to 3 days). Twelve of the 17 subjects were observed for 2 months, at which point 66% (8/12) remained patent. There were two aneurysmal dilatations. Histopathological studies and transmission electron microscopy demonstrated that freeze-dried veins undergo complete remodeling in vivo by a normal reparative process and that they do not induce a cellular immune response in the host.

THE EPIGASTRIC ISLAND FLAP

We describe a paramedian epigastric island flap fed by the perforators of the superior-inferior epigastric vessels. It is transferred with an intervening strip of muscle and fascia. A case is reported and the future possibilities of the flap are discussed.