Microsurgical Technique for 1mm Vessel End to End Anastomosis

Preparation

1. The rat is anesthetized with Ketamine 75mg/kg and Xylazine 5-10mg/kg given Intra-peritoneally
2. The groin area is prepped and draped in a sterile fashion
3. Begin by making a groin skin incision in the rat prior to using the microscope
4. Dissect out and raise the fat pad laterally out of the wound with the assistance of the microscope
5. Wrap the femoral fat pad in moist gauze

Isolate and Transect Artery

6. Adjust the microscope to high magnification and dissect the femoral artery from the vein by blunt dissection using two forceps
7. Isolate, ligate and coagulate the muscular branch
8. Applying the background under the artery to protect the vein and set the stage for the clamping
9. Clamp the artery with an approximator clamp making sure that there is enough length inside the clamp if the branch has been excised
10. Transect the vessel and irrigate with heparinized saline

Suture Front Arterial Wall

11. Trim the adventitia from the suture line to prevent it from folding inside the lumen and causing thrombosis.
12. Dilate the edges and bring the clamps closer together just prior to suturing
13. Suturing the Anastomosis: Using 10-0 nylon for 1mm diameter vessels, suture interrupted stitches in the following order:
1. One stay suture at the 12 o’clock position and one at the 6 o’clock position to bisect the vessels
2. A third stitch dividing this distance in half
3. One stitch between the middle stitch and each stay suture (2 total)
4. Flip to the posterior wall, place another stitch between the 12 and 6 o’clock position
5. Again, apply one stitch between this middle stitch and each stay suture
14. 8 stitches are usually required for a vessel of this size. The stay stitches are usually done in two equal bites, sized by two needle diameters from the edge, the rest of the stitches are usually done with a one bite stitch
15. Avoid the back wall by inserting the tips of the jewelers forceps inside the lumen for the stay sutures and middle stitch and by lifting the wall up by the one of the long tale of the middle stitch while putting the rest of the stitches in
16. Turn over the clamp to check on every front wall stitch prior to tying it to ensure that the stitch did not also capture the front wall

Suture Back Arterial Wall

17. After completing the front wall, the clamp is rotated and the same technique is performed on the posterior wall
18. After completion of all of 8 stitches, inspection is done by examining the gaps
19. If needed extra stitches are applied

Test Anastomosis

20. Remove the two clamps beginning with the distal clamp first
21. A fat pad is applied on a top of the anastomosis for hemostasis
22. Assess the patency of arterial flow by visualizing the distal pulse and performing a refill test