The effect of the delay phenomenon on the vascularity of rabbit abdominal cutaneous island flaps.

The beneficial effects of the delay phenomenon have been evaluated extensively and are widely known. However, no study has quantified the vascular changes seen in an abdominal cutaneous island flap following a surgical delay by vascular pedicle ligation. We evaluated the effect of unilateral superficial inferior epigastric and deep inferior epigastric pedicle ligation on the vascularity of a rabbit abdominal cutaneous island flap. Thirty rabbits underwent a left superficial inferior epigastric and deep inferior epigastric pedicle ligation as a delay procedure. A 19 x 15 cm abdominal cutaneous island flap was elevated at the time of sacrifice, based solely on the right superficial inferior epigastric pedicle. The flap vasculature was then evaluated by methylene blue injection and lead oxide microangiography at 0, 5, 10, 15, 21, and 27 days following the delay procedure. Methylene blue studies revealed perfusion of only the right (nonligated) side of the flap on day 0 and perfusion of the entire flap by day 15. This "capture" of the left (ligated) superficial inferior epigastric artery angiosome by day 15 could only have been achieved through enhanced cross-midline perfusion. Lead oxide microangiography revealed an increase in the number of vessels from day 0 to day 27 on both the ligated and nonligated sides in all the following: the number of large "choke" vessels (> 0.5 mm) crossing the flap midline, total number of vessels (all sizes) crossing the flap midline, and total number of vessels (all sizes) at the medial aspect of the right and left superficial inferior epigastric artery angiosomes. A statistically significant increase in these vessels was not seen until day 21. The effect of the delay phenomenon was significantly greater on the ligated side compared with the nonligated side. The areas of the flap that were relatively more ischemic following left superficial inferior epigastric pedicle ligation (medial aspect of the caudad half of the left superficial inferior epigastric artery angiosome) showed greater increases in vascularity with the delay procedure than did areas of lesser ischemia (medial aspect of the cephalad half of the right superficial inferior epigastric artery angiosome).

The effect of the delay phenomenon on the vascularity of rabbit rectus abdominis muscles.

The transverse rectus abdominis muscle (TRAM) flap has become the "gold standard" for autogenous breast tissue reconstruction. Complications are reported in 10 to 40 percent of patients undergoing this procedure, and many are related to soft-tissue necrosis secondary to ischemia. Various methods have been proposed to improve TRAM flap survival, including surgical delay of the flap. The beneficial effects of the delay phenomenon have been well established in laboratory studies and clinical evaluations. Many investigators agree that the delay phenomenon will enhance arterial inflow and venous outflow from the TRAM flap. No study has quantified the changes seen in the rectus abdominis muscle following a delay procedure. In this prospective, controlled, and blinded experiment, we evaluate the effect of a unilateral superficial inferior epigastric and deep inferior epigastric artery and vein ligation on the vascularity of the rectus abdominis muscles in rabbits. Thirty-eight rabbits underwent a left superficial inferior epigastric and deep inferior epigastric pedicle ligation as a delay procedure. The rectus abdominis muscle vasculature was then evaluated by lead oxide microangiography at 0, 5, 10, 15, 21, and 27 days following the delay procedure. Magnification (x 2) was used to count the number of vessels at the periphery of the deep inferior epigastric artery angiosomes in the microangiograms. An increase in the number of vessels from day 0 to day 27 was seen on both the ligated and nonligated sides in all the following: the number of large (> 0.5 mm) "choke" vessels and total number of vessels (all sizes) crossing the abdominal wall midline and the total number of vessels (all sizes) at the medial, superior, and lateral aspects of the right and left deep inferior epigastric artery angiosomes. A statistically significant increase in these vessels was not seen until day 21. The effect of the delay phenomenon was significantly greater on the ligated side compared with the nonligated side. The areas of the rectus abdominis muscles that were relatively more ischemic following left deep inferior epigastric pedicle ligation (medial aspect of the left deep inferior epigastric artery angiosome) showed greater increases in vascularity with the delay procedure than did areas of lesser ischemia (lateral aspect of the right deep inferior epigastric artery angiosome).

Ruptured jejunum following Heimlich maneuver.

The Heimlich maneuver, over time, has proved to be a useful resuscitative procedure in the management of cases with airway occlusion secondary to foreign body. Medical treatments, however, can have side effects, and this maneuver is no exception. A previously unreported complication is presented, that of jejunal rupture. The proper application of the maneuver minimizes the number of side effects; however, since they do occur, it is suggested that all persons subject to this maneuver be subsequently evaluated by a physician as soon after the incident as is practicable.

Stereomicroscopy as a diagnostic aid in evaluating the viability of island flaps: an experimental study.

This study entailed direct stereomicroscopic observations of rat abdominal island flaps and the sequence of vascular events that occurred during and after occlusion by clamping of the individual femoral vessels for varying time intervals of up to 16 hours. The vascular changes and the status of the circulation in the flap vasculature, including the timing of complete hemal stasis and resumption of flow, following the application and subsequent release of the vessel clamp were observed and correlated with flap viability and behavior. This study also included a grading system of the vascular changes observed under a stereomicroscope. From these findings, it is suggested that in vivo stereomicroscopy may serve as a new and simple clinical tool for the early diagnosis of thrombosis at the site of microvascular anastomosis of a free flap transfer and may define time limits during which the anastomosis can be successfully corrected and the flap salvaged.

The effects of preservation on microvascular vein grafts in rats.

Segments 15 mm in length were excised from the femoral veins of rats and preserved by refrigeration at 4 C in lactated Ringer's solution for periods up to 21 days. The findings show that veins can be preserved for up to seven days and successfully grafted to recipients. Although there was some success in preserving vein segments for more than seven days, a high rate of thrombosis occurred after implantation in the recipients. It is generally accepted that damaged endothelium causes thrombosis. The light and electron microscopic observations in this study, however, suggest that the condition of the endothelium may not be the only important factor in the patency of small vessels. A thickened and prominent elastic lamina may also play a role in keeping the lumen open.

The microvascular technique of vein grafting in rats as a training and experimental model.

Techniques for obtaining and implanting vein grafts in the femoral arteries of rats are described. Grafts 5 mm in length can be removed from the femoral vein without ligating any side branches; a 15-mm segment is the maximum graft that can be obtained from the femoral vein in a rat. This requires ligation and division of all the branches between the inguinal ligament and the great saphenous vein. The superficial epigastric vein also can be used as a source of grafts to be used in the femoral artery. In this study, neither the femoral nor the superficial epigastric vein appeared to have functioning valves. Therefore, reversing the vein graft before implantation was not necessary.