You should be able to place 2 or 3 more intervening sutures. Start near the stay suture farthest from you, and work towards yourself. Try to perform each stitch with only 1 pass (this differs from placement of the stay sutures which are placed with 2 passes). With each stitch, leave an adequate loop of suture to allow you to tie. Once all stitches have been placed, cut the loops in the middle. Then tie each strand successively, starting with the strands near the stay sutures and working towards the middle. You only need to cut one tail off each knot; leave the other one long which then you can use as a handle to manipulate the vessel as needed.
While you are suturing, take steps to avoid going through the back wall.
- Have the tip of your needle pointing horizontally along the surface of the vessel, never pointing down into it.
- Always see where the tip of your needle is going – never guess.
- Lift up the wall you are suturing to separate it from the back wall. You can lift up the wall by using the tips of your left-hand forceps inside the vessel, by picking up the adjoining suture, or by picking up the adventitia.
Turn the clamp over, and cut and release the stay sutures from the clamps.
To assess patency, fill a 10 cc syringe with water. Apply a blunt fill needle to the syringe. Place the needle into the proximal end of the blood vessel and secure circumferentially with a 5.0 Vicryl suture. Slowly infuse water, and check the anastomosis under the microscope for leakage. You can also assess your anastomosis by using the microscissors to cut your vessel longitudinally across the anastomosis. Under the microscope you can inspect the stitches for equal spacing, equal distance from edge, parallel orientation, full thickness bites, vessel wall eversion, and appropriate intima-to-intima contact.
Patency Testing in the OR:
- Observation: A patent artery should pulsate distal to the anastomosis. However, a pulsatile transmission could still carry through a thrombosed anastomosis.
- Flicker Test: Place a closed forceps beneath the vessel distal to the anastomosis. As you stretch and gradually occlude the vessel, you will see alternating collapse and filling of the vessel.
- Milking Test (Double Occlusion Test): This test is somewhat traumatic. Occlude the vessel with forceps distal to the anastomosis. Place another forceps just distal to the first and milk the vessel for several millimeters away from the anastomosis. Occlude the emptied vessel, and release the proximal forceps. You should see rapid filling from proximal to distal.
- ICG: indocyanine green is injected into a peripheral vein. The vessels are illuminated with a laser, and the fluorescence is picked up by a charged couple device video camera. Flow is assessed by: (i) visual quality of the arterial anastomosis and flow, (ii) quality of the dye flow through the microcirculation of the flap and (iii) quality of the distal opacification distal to the venous anastomosis.
When you are done, please be diligent about cleaning. Instruments can be sprayed with ethanol. The spray bottles should be located throughout the room. Place the instruments carefully back into the metal holding container near the microscope. Clean tables and cutting board with the ethanol spray. Turn off the microscope light. Throw away any unused chicken feet. Be respectful of researchers who are working in the lab. Do not work beyond your allotted time.