Anastomotic concept – 120 degrees, 9 stitches
Nine stitches are sufficient at this vessel diameter.
Here, we use 10.0 suture.
Higher magnification is required than with the previous models, to allow accurate stitch placement in a comparatively smaller vessel. Stitches one and two are placed 120 degrees apart. Stitch three is placed a third of the distance between them. Place stitch four midway between its neighbors again. This simple way of thinking may help avoid a situation in which the stitches in a 120-degree segment are placed wrongly. Like this, or this. The midline stitch on the posterior wall is number five and as on the front wall, stitches six and eight are placed at a third of a 120 degree segment from their neighbors while stitches seven and nine are placed midway between their neighbors again.
Anastomosis – 120 degrees, 9 stitches
Place stitches one and two. Numbers three and four complete the anterior wall.
Whenever the vessel dilator is too large to be inserted into the vessel between two stitches, you can pull up a neighboring thread to prevent a backstitch.
Flip over the approximator and place stitch five in the middle of the posterior wall. Finish the anastomosis placing stitches six through nine.
Here is the finished anastomosis.
Open the distal clamp first and wait for 30 seconds. Then open the proximal clamp. Assess the patency of the anastomosis by performing an Acland test.
If your anastomosis is patent, cover it up with moist gauze and leave it alone for 20 minutes. Then test its patency once more.
You can use the same vessel to repeat the exercise for as often as you can approximate the vessel ends, or you can use the same animal for another exercise on abdominal vessels, contralateral femoral vessels or neck vessels.
Advanced/optional: anastomosis – 120 degrees, 6 stitches
Just as the rat abdominal aorta model can be performed as a twelve or ninestitch exercise, the anastomoses of the rat femoral vessels can be carried out with nine or six stitches, as long as all stitches are perfectly spaced.
Minor bleeding can generally be stopped with gentle compression, while a smaller number of stitches pose a lesser risk of injuring the vessel wall. This is especially important for venous anastomoses since the venous vessel wall is generally more fragile than that of the artery.