Stitch placement – basic concept
Before we place the first stitches, here is an idea of what defines a perfect stitch and why you should try to make each stitch as good as you can. The distance to the cut edges, or bite, on either side of the suture line should be symmetric, so as to prevent uneven distribution of tension and to minimize risk of damage to the tissue. Each stitch should be exactly perpendicular to the suture line and all stitches should be parallel to each other, in order to avoid creating turbulence, aiding adhesion of blood components to sutures and small defects in a vessel’s intimal layer. All stitches should have the same distance to each other, so that you obtain an anastomosis that does not leak, using a minimum number of stitches.
Stitch placement – indirect stitch placement
In order to place stitches with high precision, it is helpful to use a relatively high magnification.
Place your needle holder exactly parallel to the cut edge, to get the needle exactly perpendicular to it. Decide at which point you want to penetrate the tissue with the needle tip. Support the tissue around this point from the underside with your opened forceps, to provide contra-pressure. Now rotate the needle through the tissue, until your needle holder makes contact with the vessel wall. Let go of the needle and take it out from the underside. With the help of the forceps grasping the thread, correctly position the needle in the needle holder again. Verify the distance of the stitch to the cut edge and select a point on the opposite side of the mcut that is equally far from the cut edge. Aim at this point and rotate the needle through the tissue.
Stitch placement – direct stitch placement
Once you have accurately placed several indirect stitches, you should proceed with direct stitches by passing the needle through the tissue on both sides of the cut in one single movement.
If desired, using a higher magnification will allow you to place a stich even more precisely.
Stitch placement – pitfalls, tips and tricks
Avoid grabbing the cut edge in its full thickness. In a real vessel this would potentially cause serious damage.
Never touch the needle at its tip. A blunt needle will tear the tissue it penetrates.
Try not to push the needle: instead of rotating it, you may tear the vessel wall.
Avoid placing stitches oblique to the cut: turbulence inside a vessel favors thrombosis.
Do not place stitches with asymmetric distances to the cut edges. Uneven distribution of tension may cause the suture to rip through the vessel wall. In addition, overlapping or inversion of the edges may occur, leading to leakage, or thrombosis.
If stitches are placed too close to the cut edges, appreciating symmetry of bite will be far more difficult and the risk of tearing the vessel edge is substantially higher.
To make the needle project further out of the tissue to be able to take it out without touching its tip, simply let go of the needle, grasp it a little closer to its rear end and rotate it a little more.
If you pick up the needle close to its rear end, more of it will project out of the tissue and it will be easier to pass the needle through the tissue without touching its tip.
If, on the other hand, you pick up the needle at about its midpoint, it will be easier to penetrate the tissue at a steeper angle. This is important when thick vessel walls are encountered, so that you can penetrate all vessel wall layers at a similar distance to the cut edge.