A Training and Testing System for Performing Vascular Reconstruction In Vitro

In this video, we introduce a novel training and testing system where the trainee can complete manual vascular reconstruction in vitro individually. Manual vascular reconstruction training is essential for young surgeons. In this study, we introduce a novel training and a testing system where the trainee can complete the manual vascular reconstruction in vitro individually using magnetic anchoring technique and the quality of reconstruction can be tested on it.

This is vascular reconstruction training machine consisting two parts, control panel and the operating floor, at 0.9-percentage saline into machine before we start training. These are right and left iliac veins harvested from Burma pigs. Use tissue scissors to trim the ends of the veins and clear the excess tissues on the wall of the veins to make the veins smooth.

These are magnetic vascular fracture, magnetic suture fracture, and magnetic suture puller. Tie the two veins on the water inlet and the water outlet of training machine with two of the silk sutures. In this video, we adopt the method of two point vascular anastamosis.

Adjust the lens of water outlined of the training machine and ensure free tension of the ends of the two veins in a parallel direction. String in the veins and lay two 4-0 traction sutures at the six o'clock and 12 o'clock positions. Insert the needle of traction sutures from outside of the vein and then, insert from the inside of the outer vein.

Wipe out the glove and the suture to avoid damaging the suture. Gently tie at least five knots to avoid tearing the wall of the veins. Use two stainless steel clamps of the magnetic suture tractor to grasp the traction sutures and attract the circular magnets of magnetic suture tractors on the ferromagnetic stainless steel operating floor.

Adjust the position of magnetic attraction and it ensures that ends of two veins are stretched in a vertical direction. Use two vascular clamps of the magnetic vascular tractor to clamp the interior wall of the veins and the tractor, the circular magnets, of magnetic vascular tractors on the operating floor. Adjust the position of attraction and ensure that the interior walls of the veins are retracted and the posterior walls of the veins are clearly exposed.

Attract the magnetic suture puller on operating floor. Leave the tail segment of the polypropylene suture at the 12 o'clock position for the traction suture and use the segment with the needle for continuous suture. Ensure the contact between intima to intima of two veins.

Insert the first suture from the outside of the vein to the inside. In subsequent sutures, insert the needle from the inside of the vein and then, insert from the outside of the other vein. Check that the suture is not loose.

After one suture, ensure that polypropylene suture is hung on the magnetic suture puller and pull the polypropylene gently until the magnetic ball presses the polypropylene. Extract the end with the needle of the suture with a force of about 0.3 newton whose direction is subsequently in parallel with the ball of the magnetic suture puller and then, continue on the next stitch. By using the magnetic suture puller, the tail of the polypropylene suture will be sufficiently tied.

As the suture continue, the polypropylene suture will become shorter. According the length of the suture, select the most suitable one of three magnetic balls and then, press the suture under the magnetic ball. Insert the left suture from the inside of the vein to the outside to ensure contact between intima to intima of two veins.

To avoid stenosis after anastamosis, ensure that the same suture margin and the needle spacing is maintained about one millimeter. Tie five millimeter away from the vein's wall to prevent the suture stenosis. This is also known as the growth factor.

It is a reserved space away from the vessel wall when tying the first knot after anastamosis, so that vessels can expand rather than stenosis. The method of tying knots was same as before. After anastamosis of posterior walls, remove the magnetic vascular tractor and leave the tail as the tractor suture and use the segment with the needle at the six o'clock position for the anastamosis of the anterior walls.

Insert the needle from outside of the vein and then, insert from inside of the other vein. Other methods were consistent with the method of anastamosis of posterior walls. The method to ensure the contact between intima to intima of two veins, the suture being not loose and not stenosis after anastamosis were consistent with the method of anastamosis in the posterior.

After anastamosis of anterior walls, cut off two traction sutures. Set the peak perfusion pressure at two kilopascal for five seconds in 25 degrees centigrade with the deviation of 0.1 kilopascal on the control panel. If the vein does not leak, then the anastomosis succeeds.

The profusion pressure ascended to the pique pressure and it maintained for five seconds. The length of the traction were in 30 centimeters and the range of traction for the magnetic tractor could provide is zero to 1.8 newton. The results of the breaking strength test show the magnetic suture puller does not damage the polypropylene suture.

The results of the live microscope test show that there is no significant difference between the manual group and the magnetic puller group. In summary, with the aid of magnetic tractors and the magnetic suture puller, the trainee can perform manual vascular extraction individually.