Left carotid bifurcation eversion endarterectomy (EEA) in symptomatic carotid bifurcation stenosis – Vascular Surgery - vascular surgery
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Left cervical access
Dissecting the left common carotid artery
Central exposure of the anterior aspect of the common carotid artery (CCA), which is then freed circumferentially; encircle it with a vessel loop as tourniquet. Continue the dissection cephalad mobilizing and medializing the cervical ansa. Dissect the facial vein and divide it between suture ligatures.
1. Golden rule for dissection: Because of the risk of embolization, dissect the surrounding tissue off the CCA, not the other way around. The vessel should be handled as little as possible when dissecting.
2. The ansa cervicalis is the landmark leading straight to the hypoglossal nerve (CN XII). If dissection is approached differently, as in the video, problems will arise at the level of the internal carotid artery at the latest: The latter must then be subsequently medialized, which not only wastes time but also increases the risk of accidental injury to the hypoglossal nerve.
3. The facial vein should not be secured with simple ligatures, but always with suture ligatures. During emergence from anesthesia and also during coughing, the cervical veins are subjected to high pressures, which can cause simple ligatures to slip off, resulting in intense bleeding.
Dissecting the carotid bifurcation, mobilizing the hypoglossal nerve
Mobilize the hypoglossal nerve and ansa cervicalis by transecting between clips small, vascular branches tethering the nerve, and divide larger vessels between ligatures. Expose the external carotid artery (ECA) and isolate the superior thyroid artery. Encircle the ECA and expose the internal carotid artery (ICA) 1-2 cm above the calcification already visible from the outside. In the video, this requires divisdion of the occipital artery, as it tethers the hypoglossal nerve and thus blocks peripheral (= cephalad) access to the ICA.
1. This step in the procedure requires that the cephalic angle of the wound be widened with blunt (carotid) retractors. Do not exert too much pressure as this could damage the oral branch of the facial nerve (postoperative angular drooping of the mouth).
2. Dissect only lateral to the ansa cervicalis. Medial dissection may impair hypoglossal nerve blood flow.
3. If enlarged lymph nodes are encountered during dissection, sweep these mediad en-bloc.
4. Here too, ensure: dissect perivascular tissue off the vessels, not the other way round.
5. Subtle sparing of vagus nerve! Usually, it is located “posteriad” between the ICA and internal jugular vein, but occasionally also more “anteriad” between the vessels. In arteriosclerotic perivascular adhesions, such as in the video, the extremely sensitive nerve must be carefully freed from the carotid artery so that it does not later get caught between the branches of the vascular clamps. Likewise, ensure that the carotid retractor does not catch the vagus nerve.
6. If extensive exposure of the ICA is required cephalad, the digastric muscle and occasionally the glossopharyngeal nerve (N. IX) will be encountered. This nerve must also be carefully spared, otherwise patients will suffer from extremely agonizing dyssynergia when swallowing.
7. If possible, do not encircle the hypoglossal nerve (N. XII), as this would require unnecessary circumferential dissection of it. Excessive devascularization and to-and-fro movement of the nerve may damage it (sequelae: muffled speech, patients biting their ipsilateral tongue when chewing). Instead of encircling, it may be temporarily sutured up to the mandibular musculature. Do this by solely grasping the perineurium and placing a loose suture ("air knot").
Cross-clamping the carotid bifurcation, EEA of ICA and TEA of carotid bifurcation
Administer 5000 IU of heparin systemically and wait for it to fully circulate, ventilate the patient with pure oxygen, and then cross-clamp the carotid bifurcation: first, the superior thyroid artery (bulldog clamp), followed by the CCA (120° clamp), ICA (Gregory-soft clamp), and finally the ECA (curved clamp).
First, perform EEA of the ICA: Do this by transecting the ICA obliquely at the carotid bifurcation and grasping its outer wall with a Pean forceps. Under gentle traction on the ICA, peel away the intimal cylinder with a vascular spatula. Evaginating the outer layers of the wall and peeling them back, comparable to pulling off a stocking, completes the peeling without leaving an endpoint edge/step-up. Probe the ICA with Overholt forceps. After checking for backflow and flushing, administer 1000 - 2000 IU of heparin saline into the peripheral (cranial) stump of the ICA.
After repositioning and rotating the CCA clamp for better exposure and easier handling, perform the local TEA of the CCA. Do this by extending the CCA incision centrad (caudad) with Pott scissors. Mobilize the intima cylinder with a vascular spatula and remove the plaque material and debris step by step. Flush the CCA with heparin saline.
In the video, the arteriosclerotic plaques extend far into the ECA and cannot be removed entirely without an additional incision, which is why this step is omitted.
1. Dissect the ICA far enough peripherally (cephalad). Otherwise, this may result in a dissection difficult, if not impossible, to control. If faced with imminent dissection, securing the intima peripherally with sutures is not recommended, as further dissection or even embolization may still ensue.
2. As shown in the video, cross-clamping times of 12–15 minutes usually do not necessitate intraluminal shunting.
3. When placing an intraluminal shunt into the cranial ICA, care must be taken that the shunt does not adhere to the base of the skull. This requires briefly opening the clamp on the shunt to check the back-bleeding from the ICA. After craniad instillation of 1000 IU heparin saline solution through the shunt, the latter must be flushed before inserting it into the CCA. Some operators prefer the reverse maneuver (inserting the shunt into the CCAfirst, flushing, and only then into the ICA). Both groups argue that this avoids embolization via the ICA.
Reinserting the ICA
Intraoperative completion angiogram