Name:
09 Carotid
Description:
09 Carotid
Thumbnail URL:
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Duration:
T00H07M22S
Embed URL:
https://stream.cadmore.media/player/68bd09b2-6e09-43c1-ae3b-9b44a6812bd6
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/68bd09b2-6e09-43c1-ae3b-9b44a6812bd6/0920Carotid.mov?sv=2019-02-02&sr=c&sig=ltQ%2BuX8X2kdV3DtlSMpyGlvqK6I0pKLA0Zc1slIZ0p8%3D&st=2024-12-21T17%3A06%3A05Z&se=2024-12-21T19%3A11%3A05Z&sp=r
Upload Date:
2022-03-03T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
In this video, we will discuss the proper techniques to expose the carotid artery in the neck.
Segment:1 Objectives.
We will begin by reviewing the anatomy, followed by the necessary instruments and proper positioning. Then we will discuss the exposure of the proximal carotid artery, the carotid bifurcation, and the distal carotid artery to its entry into the skull. And, finally, the tips and pitfalls of this exposure.
Segment:2 Anatomy.
The carotid artery, internal jugular vein, and the vagus nerve in the neck are contained within the carotid sheath.
The common carotid artery lies anterior and the internal jugular vein lateral. The vagus nerve is located posterior between the two vessels. The carotid artery bifurcates the neck, giving the internal and external branches. The internal carotid artery has no branches in the neck, while the external has several NAMED branches. Note that the hypoglossal nerve traverses the neck near the location of the carotid bifurcation.
Segment:3 Instrumentation and Positioning.
The patient should be positioned supine, with the ipsilateral arm tucked, and if the cervical spine is cleared the neck is extended and turned to the contralateral side.
The preparation should include the neck to the mandible and ear, the chest and the groin in case a vein graft is required. Instruments should include a vascular tray, Fogarty catheters, shunt and vascular conduits, heparin, and lidocaine solution in the event that hemodynamic instability occurs during the dissection on the carotid bifurcation. The skin incision is made along the anterior border of the sternocleidomastoid muscle from the mastoid process to the sternal notch.
The incision may be extended posterially around the ear, if distal exposure is required, as we will see later. Once the skin and platysma are incised, the sternocleidomastoid muscle is mobilized along its anterior border, and the sternocleidomastoid muscle is retracted laterally to expose the underlying internal jugular vein and carotid sheath. With sternocleidomastoid muscle retracted, the internal jugular vein is easily visible and dissected along its length.
Note the location of the facial vein. The carotid sheath contains the common carotid artery and its bifurcation anteriorly, the internal jugular vein laterally, and the vagus nerve posteriorly between the vessels. The common carotid artery and internal jugular vein are then dissected and the vagus nerve is identified and looped. Note that small branches of the vagus nerve is constituting the ansa cervicalis and may be found on the carotid artery.
These may be divided, if needed. If exposure of the proximal most extent of the common carotid artery and the neck is required, the omohyoid muscle may be divided with little consequence, and the carotid sheath may be incised to the thoracic inlet. Further proximal exposure will require a sternotomy. At the level of the carotid bifurcation, the internal carotid artery lies lateral to the external carotid artery. The internal carotid artery has no branches in the neck, while the external carotid artery has several branches aiding in identification.
Note the location of the hypoglossal nerve, as it traverses superficially across the superior most aspect of the carotid bifurcation. Hemodynamic instability may also occur during this dissection due to stimulation of the carotid body, located in the crotch of the bifurcation. Lidocaine may be injected into the carotid body, if this occurs. In order to expose the carotid bifurcation, first the facial vein must be ligated and divided. The external carotid artery is identified by its medial location and dissection of its first branch, the superior thyroid artery.
Next, the external and internal carotid arteries are dissected. Note that during this dissection the hypoglossal nerve is identified near the bifurcation and the inferior border of the posterior digastric muscle. This nerve should be preserved. The internal and external carotid arteries are then looped for identification. If necessary, the external carotid artery may be ligated unilaterally with little sequelae.
Exposure of the distal carotid artery to the base of the skull is challenging and requires a thorough understanding of the anatomy. It requires extension of the incision posteriorly around the ear, and mandibular subluxation, which is achieved by an assistant grasping the lower teeth and pulling down and interiorly on the mandible. There are also several muscles and ligaments which may need to be divided, including the posterior digastric and stylohyoid muscles and ligament, as well as division of the styloid process.
Care should be taken to avoid injury to the glossopharyngeal nerve. The skin incision is first extended in a curvilinear fashion posteriorly around the ear. Once the incision has been extended, the posterior belly of the digastric muscle is identified, dissected, and divided using the Bovie electrocautery. In order to achieve exposure of the internal carotid artery as it enters the carotid canal, as mentioned previously, the posterior digastrics, stylohyoid muscle and ligaments must be divided.
Then the styloid process itself may be divided to expose the interal carotid artery at the base of the skull. With the posterior belly of the digastric muscle divided, the stylohyoid muscle and ligament are easily identified and similarly divided. Next, the styloid process itself is identified and divided using a rongeur. Note the course of the internal carotid artery at this level as it crosses medial and deep to the external carotid artery.
At this level, care should be taken to identify the glossopharyngeal nerve, as it crosses over the interal carotid artery. With the styloid process removed, the internal carotid artery is now exposed as it enters the carotid canal at the base of the skull.
Segment:4 Tips and Pitfalls.
Points to remember during this exposure are in a damage control situation, consider a temporary shunt versus definitive repair. If hemodynamic instability occurs during dissection of the carodic bifurcation, inject 1% lidocaine into the carotid body.
And, finally, exposure of the distal carotid artery at the skull base is challenging and requires a familiarity of the anatomy and techniques like subluxation of the mandible. Thank you.
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