For the anastomosis you should use a segment of vessel that does not have a collateral vessel stump on either side and which is relatively close to the midline
of your dissection. Make sure to consider the collaterals on the underside of the vessel.
To place a piece of synthetic background material behind the vessel, simply lift it up and drag the material into position.
The background increases the contrast, simplifies the picture and clearly separates the vessel you are working on and your suture from surrounding tissues.
In this exercise, the background material should be just slightly larger than the approximator set at its maximum distance.
Hold the approximator, set at its maximum distance, over the vessel. Test to find its correct position, making sure there are no collateral vessel stumps midway between the approximator clamps, or in between the arms of the clamps.
Assure yourself that the vessel is free on all sides not only between the approximator clamps, but also proximal and distal to them. This way you will have the maximum length of vessel to work on, while not twisting the vessel next to the approximator when flipping it over to work on the vessel’s back wall.
Use the clamp applying forceps to keep the approximator clamp open as wide as possible, lift up the vessel and carefully place it in the clamp. Before closing each clamp, make sure that the vessel is perpendicular to it and about 1 mm from its tip.
Approximator placement – pitfalls, tips and tricks
If the vessel is placed too far from the tips of the clamps, flipping over the approximator to suture the back wall of the vessel may lead to stretching and spasm of the vessel proximal and distal to the approximator.
This also depends on whether you have dissected the underside of the vessel sufficiently well.
Try not to place the vessel too close to the tips of the clamps, either. Blood flow would not be completely obstructed, and the resulting leakage would make tissues or your suture sticky or even cloud the operating field.
Do not allow the vessel to turn around its own axis while placing it in the approximator. The resulting twist may be traumatic to the vessel, or may narrow its lumen, reducing blood flow.
Avoid placing the vessel obliquely in either clamp. The anastomosis would become somewhat more difficult to perform, since the approximator clamps and the vessel itself would no longer form the same simple visual reference mstructures for stitch placement.