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03 microsurgical dissection

Rat femoral vein model microsurgical dissection

06.03 Rat Femoral Vein Model Microsurgical dissection

Microsurgical dissection

In order not to point your instrument tips at the fragile and thin-walled vein, begin your microsurgical dissection by opening the common sheath in a line overlying the artery.
This time, place the line just a little closer to the vein than in the previous model.
To separate the vein from the artery, tear the adhesions between the vessels away from the artery, or use spreading movements between the two.
This way, you are touching the vein as little as necessary.
Free the vein on all its sides between the inguinal ligament and the intersection with the inferior epigastric vessels.
Beware of the collateral on the underside of the vein.
Verify the completeness of the dissection by moving an instrument along the vessel’s underside.
Now ligate the collateral, pulling the thread across the main vessel to make sure the ligature is placed right at the intersection of both vessels.
Pulling on the vein’s collateral itself while closing the ligature poses the risk of constricting the main vessel by pulling part of its thin wall into the closing loop.
Place another ligature in some distance to the main vessel.
Cut the collateral in a safe distance from the ligatures.
Should you encounter additional collaterals, ligate and cut them as well.
Collateral vessel stumps can often be left sufficiently long to allow grasping their end without risking pulling off the ligature. This way the main vessel can be handled atraumatically.

Thrombus and blood clot formation

Owing to the fragility of the venous wall and the lower speed of flow in veins, as compared to arteries, even minor imprecisions in vessel handling may lead to thrombosis.
After finishing the dissection, check whether a thrombus is present by placing an instrument under the vessel, gently pressing it up against the vessel and moving it along the entire dissected length. This test may help distinguish whether occlusion of the vessel was caused by a mistake in dissection or in anastomosis, depending on the location of the thrombus. Example.
In case of a small thrombus, wait for 20 minutes and repeat the test. The thrombus may have dissolved, as in our example. A large thrombus on the other hand is highly unlikely to dissolve and should be removed immediately.
Stagnation of blood flow proximal to a thrombus can lead to blood clot formation, further worsening the situation.