Two-Dimensional X-Ray Angiography to Examine Fine Vascular Structure Using a Silicone Rubber Injection Compound

This method can help answer key questions in the reconstructive surgery field about how to perform the perforative lift surgery. Main advantage of this technique is that the variation of fine vascular structures, such as choke vessels, can be performed easily under various vascular flap conditions. To establish a flap condition, confirm the appropriate level of sedation by a lack of response to toe pinch in an anesthetized 200 to 250 gram 7 week old male Sprague-Dawley rat and mark a 4 by 12 centimeter circumferential skin flap design from the lower abdomen to the back.

With the center of the flap halfway between the xiphoid process and the penis. Use a surgical blade to make the incision as marked and use scissors to dissect the flap, including the skin and panniculus carnosus. Dissect around the vascular pedicle at the lower abdomen and use a microscope or surgical loop to expose the vascular tissue.

Ligate the vessels and divide the flap along the dorsal midline. The return the flap to its original position and secure the flap with the skin stapler. It is important to make flaps that have obvious vascular territories to allow changes to be easily made to the vascular condition of the flap as required for doing experimental protocol.

On the day of the procedure, make a 2 centimeter midline skin incision between the scapulae and use mosquito forceps and blunt scissors to expose the salivary gland complex. After longitudinal dissection of the omohyoid muscle, dissect around the common carotid artery and use black silk to retract the cephalic and caudal sides of the artery. Make a tie on the proximal suture and keep traction to maintain engorgement of the artery and loosely place the caudal suture.

The insert a 24 gauge catheter into the prepared artery and secure the catheter with the caudal suture. Connect a three way stopcock to the catheter and use an empty syringe to apply negative pressure to the catheter confirming a back flow of blood into the catheter. Next, inject 25 to 30 milliliters of freshly prepared silicone rubber injection compound into the catheter until the colors of the eye and foot have changed.

When all of the compound has been injected, lock the three way stopcock and allow the agent to solidify for about 15 minutes. Then place a protective barrier around the syringe of compound so as not to contaminate the radio opaque agent. And remove the syringe from the stopcock.

To harvest the specimen, use a surgical blade to make an incision in the panniculus carnosus one centimeter away from the flap to prevent damage to any vascular structures inside the flap and dissect around the flap below the panniculus carnosus plane. Then use scissors to harvest the tissue including the flap and and vascular pedicle within the flap and use a five o silk suture to ligate the pedicle of the flap, separating the flap from the body. Silicone rubber injection angiography clearly reveals fine vascular structures, allowing the acquisition of high-quality angiographic images of the dilated choke veins even under otherwise difficult imaging conditions.

For example, in this representative experiment, it can be observed that all of the flaps were elevated based on the deep circumflex iliac artery and vein before being supercharged with arteries from various locations. If an entire flap is divided into four zones as the standard with the main vessel charging the flap territory, the angiographic agent that reaches the main vessel charges the next distal zone beyond the supercharging artery. The dilated choke vein can also be observed, even though it was not seen in the normal skin angiography.

Once mastered, this technique can be completed in one hour per rat if it is performed properly. While attempting this procedure, it is important to remember not to contaminate or spill the angiographic agent during the injection. After watching this video, you should have a good understanding of how to make a specific condition flap and to perform an angiography.