High Bifurcation of the Common Carotid Artery with Pentafurcation of the External Carotid Artery: Case Series with Review of Literature

The AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Extracranial Cerebrovascular System.

COMBINED INTERNAL CAROTID AND HYPOGLOSSAL ARTERY ENDARTERECTOMIES IN A SYMPTOM-FREE PATIENT WITH CONTRALATERAL INTERNAL CAROTID ARTERY OCCLUSION

Thomas Willis, the man for whom this lecture is named, was an Englishman and a leading neuroanatomist of the 17th century. Born in 1621, he attended Oxford University, graduating from Christ Church College in 1639. While still at Oxford, he became Sedleian Professor of Natural History in 1660. He did much experimental work with his associate Richard Lower. He performed injection experiments on cadavers and noted that if he injected the carotid artery on one side, the dye solution would come forth from the carotid on the opposite side. In 1664 Willis published his monumental work Cerebri Anatome , the most complete and accurate account of the nervous system that had hitherto appeared. In it he contributed the term “neurology” to medicine, a word derived from the Greek, meaning “sinew,” “tendon,” or “bowstring.” The word was translated and introduced into the English language in 1681 in Samuel Pordage's translation of Willis' work. Cerebri Anatome contains a classification of the cerebral nerves, the first description of the eleventh nerve, and a description of the hexagonal network of arteries at the base of the brain that we know as the circle of Willis. Although others had described the circle before Willis, he was the first to grasp its physiological and pathological significance. He records the clinical histories of two patients in whom he suggests that the anatomic configuration of the arteries at the base of the brain could prevent apoplexy. The book was illustrated by Christopher Wren, an associate of Willis at Oxford, later to become England's leading architect and designer of St Paul's Cathedral, numerous other English churches, and many historic secular buildings. Willis moved to London in 1666 and acquired the largest fashionable practice of his day. He continued his careful clinical observations and made a number of other important …

To the Editor: Carotid body tumor (CBT) is a highly vascular neoplasm of neural crest origin arising in paraganglial cells of the carotid bifurcation. Branches from external carotid artery or glomic artery arising at the bifurcation of common carotid artery dominate in the blood supply mode. Only very few cases with supplementary blood supply from an internal carotid artery (ICA) have been reported in literature, but were still short of imaging proof.[1,2] Here, we report an extremely rare case of CBT with blood supply from ICA, which had been performed 4 times of unaccomplished surgical explorations before the tumor was excised during the 5th time of surgery. She also presented carotid sinus syndrome that was also extremely rare among CBT patients. A 52-year-old woman was admitted to the Department of Otolaryngology Head and Neck Surgery with a history of neck mass on the right side for 25 years and 4 times of surgical explorations. She felt dizziness when the mass had grown for 20 years, experienced palpitation and vomiting once 5 years ago when she was working in the field, faintness and falling to the bed twice at later time, but never had vertigo. Physical examination revealed a mass sized 8 cm × 10 cm in the right neck. Enhanced computed tomography (CT) angiography and digital subtraction angiography demonstrated a mass located at carotid bifurcation with rich blood supply germinated from ICA stump, the distal end of ICA was almost obstructed [Figure ​[Figure1a1a and ​and1b].1b]. Routine electrocardiogram revealed no abnormalities. Matas test was unable to be carried out because the tumor was so large, extending from the right skull base to the supraclavicular fossa, which made a tangible compression infeasible, while balloon occlusion test proved that a temporary 30 min occlusion of ICA brought about no significant symptoms and signs of neurological or sensorimotor system, preoperative embolization was not routinely carried out.[2] During surgery, the internal jugular vein, vagus nerve, hypoglossal nerve and sympathetic trunk were preserved. The ICA and external carotid arteries were hard to free from surrounding tissues, and a carotid artery bypass was also not easy to put into the carotid artery. When the ICA was cut across, the blood oozed out very slow rather than ejaculated [Figure 1c]. Based on the occlusion test results, the carotid arteries including internal, external and common carotid artery were ligated. The patient was followed for 2 years and was found to be free from previous dizziness or faintness. A temporary choking that presented before surgery lasted for half an year after surgery, permanent right vocal cord paralysis and slight ptosis on the right side were also observed. The postoperative CT angiography and cervical vascular duplex demonstrated no further significant abnormality though interruption of the carotid artery persisted. Figure 1 Medical imaging and operative field: (a) enhanced computed tomography demonstrating highly vascular neoplasm in the right neck; (b) digital subtraction angiogram demonstrating rich blood supply germinated from the stump of right internal carotid artery ... CBTs are asymptomatic in the majority of cases. In rare instances, they may cause vague symptoms related to the compression of the nerves of the region. The clinical symptoms characteristic of a carotid sinus syndrome (i.e., repeated fainting and falling), which are believed to be associated with carotid sinus nerve or Hering's nerve, in turn, a branch of the glossopharyngeal nerve, if disappear after the surgical removal of the tumor, constitute a unique case.[1] The blood supply of this CBT is mainly derived from ICA, which is quite different from usual cases.[3] Did the repeated surgery change the blood supply of the tumor? We could suppose that the peripheral vascular branches might be ligated during the repeated surgical exploration, then new blood supply might grow either from the external or ICA. If most of the branches from external carotid artery were interrupted, which in turn made the main part of the tumor keep attached to the ICA, new blood vessels derived from ICA become possible, then the tumor ends up with the major blood supply from ICA with the tumor growth and erosion into the ICA. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

How to Clamp and Bypass if There Is Single Artery Supply to the Head and That Contains Severe Stenosis?

Part One: For the Motion. Completion Angiography Should be Used Routinely Following Carotid Endarterectomy

The mechanism underlying the plateau or relative decrease in cerebral blood flow (CBF) during maximal incremental dynamic exercise remains unclear. We hypothesized that cerebral perfusion is limited during high-intensity dynamic exercise due to a redistribution of carotid artery blood flow. To identify the distribution of blood flow among the arteries supplying the head and brain, we evaluated common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA) and vertebral artery (VA) blood flow during dynamic exercise using Doppler ultrasound. Ten subjects performed graded cycling exercise in a semi-supine position at 40, 60 and 80% of peak oxygen uptake (VO2 peak) for 5 min at each workload. The ICA blood flow increased by 23.0 ± 4.6% (mean ± SE) from rest to exercise at 60% (VO2 peak). However, at 80% (VO2 peak), ICA blood flow returned towards near resting levels (9.6 ± 4.7% vs. rest). In contrast, ECA, CCA and VA blood flow increased proportionally with workload. The change in ICA blood flow during graded exercise was correlated with end-tidal partial pressure of CO2 (r = 0.72). The change in ICA blood flow from 60% (VO2 peak) to 80% (VO2 peak) was negatively correlated with the change in ECA blood flow (r = −0.77). Moreover, there was a significant correlation between forehead cutaneous vascular conductance and ECA blood flow during exercise (r = 0.79). These results suggest that during high-intensity dynamic exercise the plateau or decrease in ICA blood flow is partly due to a large increase in ECA blood flow, which is selectively increased to prioritize thermoregulation.

The right common carotid artery originates from the innominate (brachiocephalic) artery. The external landmark is the right sternoclavicular joint. The left common carotid artery originates directly from the aortic arch in the superior mediastinum. The carotid sheath contains the common and internal carotid arteries, the internal jugular vein, and the vagus nerve. The internal jugular vein lies lateral and superficial to the common carotid artery and vagus nerve. The vagus nerve lies posteriorly, between the artery and the vein. On occasion the vagus nerve may be located anterior to the vessels. The carotid sheath and its contents are covered superficially by the platysma, anterior margin of the sternocleidomastoid muscle, and the omohyoid muscle. Deep to the vessels are the longus colli and longus capitis muscles. Medial to the carotid sheath is the esophagus and trachea. At the level of the superior border of the thyroid cartilage, the common carotid artery bifurcates into the internal and external carotid arteries. The facial vein crosses the carotid sheath superficially to enter the internal jugular vein at the level of the carotid bifurcation. The external carotid artery lies medial to the internal carotid artery for the majority of their course. The first branch of the external carotid artery is the superior thyroid artery located near the carotid bifurcation. The internal carotid artery does not have any extracranial branches. At the level of the angle of the mandible, the internal and external carotid arteries are crossed superficially by the hypoglossal nerve (Cranial Nerve XII) and the posterior belly of the digastric muscle. The glossopharyngeal nerve (Cranial Nerve IX) passes in front of the internal carotid artery, above the hypoglossal nerve. The external carotid arteries terminate in the parotid gland, where they divide into the superficial temporal and maxillary arteries. At the level of the skull base, the internal carotid arteries cross deep and medial to the external carotid arteries to enter the carotid canal behind the styloid process.

In revascularization of internal carotid stenosis with carotid vertebrobasilar anastomoses, attention should be paid not only to the anterior circulation but also to the posterior circulation cerebral infarction. A 74-year-old man was referred for treatment of carotid artery stenosis; NASCET 75% stenosis in the right internal carotid artery and acute cerebral infarction were confirmed. Occlusion of the left subclavian artery and vascular anastomosis between the right external carotid artery and the vertebral artery were indicated, such that the right external carotid artery may maintain blood flow to the vertebrobasilar artery. Therefore, dual shunts were used for the common and internal carotid arteries and the common and external carotid arteries to maintain blood flow during carotid endarterectomy. Management of the dual shunts is difficult due to the instable parallel placement of the common carotid artery shunt balloons. To solve this problem, the "dual internal shunts technique" was performed. The first shunt was inserted into the external and common carotid arteries, and the second into the internal and common carotid arteries. The shunt balloon on the common carotid artery side was placed distal to the first shunt balloon so that the dual balloons were placed in a tandem position. The proximal balloon was subsequently deflated gradually to improve flow in both shunts. The procedure is technically easy and safe.

Aortic Root Anomalies of the Neck Presenting in Adults. Review of the Literature with Three Case Reports

Understanding the anatomical variations involving bifurcation of the common carotid artery, positioning of external and internal carotid arteries, and branching of the external carotid artery are of vital importance in neck surgeries such as carotid endarterectomies (CEA). The neck of a 51-year-old female donor body was dissected to demonstrate the arterial network. Bifurcation of the common carotid artery occurred at the level of the C6-C7 intervertebral disc, significantly inferior to the generally accepted and taught anatomical location at the level of intervertebral disc between C3 and C4 vertebrae. When the arteries were followed superiorly after the bifurcation, a unique second variation was observed: translocation of the external and internal carotid arteries. The external carotid artery was located posterolaterally and the internal carotid artery was located more medially. Finally, a third variation was discovered in the form of a common thyrolingual trunk that gave rise to superior thyroid and lingual arteries rather than these arising independently from the external carotid artery. We report a unique triple variation within the major arteries of the neck that has not been previously reported in surveyed literature. This case report may provide useful information for cardiovascular surgeons performing CEAand for otolaryngologists performing prophylactic arterial ligation following transoral robotic surgery for oropharyngeal cancer resection.

Based on the strength of randomized trials from the 1990s, major societal guidelines recommend carotid endarterectomy (CEA) for severe (≥70%), symptomatic carotid stenosis if an operative stroke/death rate of <6% can be maintained (history and major trials in carotid revascularization are summarized in the online-only Data Supplement).1–4 Though the benefit is less evident, most guidelines also recommend consideration of CEA for 50% to 69% symptomatic stenosis.2–4 There are subtle differences in recommendations regarding carotid artery stenting (CAS) in symptomatic patients. Some guidelines stipulate that CEA should be preferred over CAS in patients with severe (≥70%) symptomatic carotid stenosis,2,5 especially if >70 years old,4 whereas others position CAS as an alternative.1,3 Though the risk of operative stroke/death is higher with CAS, major randomized clinical trials (RCTs) report event rates under the recommended 6% cutoff for both treatment modalities. Regarding asymptomatic disease, CEA is recommended for patients with stenosis ≥60% to 70% in highly selected patients as long as operative stroke/death rates <3% can be maintained.1 A predicted life expectancy of at least 3 to 5 years has also been suggested.2 The 3% threshold has been easily met by CEA cohorts in the CREST (Carotid Revascularization Endarterectomy Versus Stenting Trial; 1.4%)6 and the ACT1 (Asymptomatic Carotid Trial; 1.7%),7 suggesting that an even lower threshold may be appropriate. Controversially, some guidelines have recommended that CAS can be considered in highly selected patients with asymptomatic carotid stenosis ≥60% to 70%,1,4,8 whereas others argue that the evidence remains insufficient.2 The lack of consensus in the management of asymptomatic carotid stenosis is reflective of an ongoing need for high-quality RCT data to guide practice. ### CEA Operative Stroke Risk and High Risk Designation Most clinical trials in carotid revascularization have focused …

Objective To discuss the microsurgical anatomy of carotid bifurcation and external branch of the superior laryngeal nerve (EBSLN), and to explore the operative techniques in carotid endarterectomy. Methods The carotid bifurcation (20 sides) of 10 cadaveric heads was studied by using microanatomy from January 2017 to January 2018. The distance between bifurcation of carotid artery to peripheral bone structure, and the distances between point of EBSLN to medial margin of the carotid artery to mandibular angle, most prominent point of the larynx, apex of the mastoid, and bifurcation of carotid artery were measured. Results (1) The vertical distance from carotid bifurcation to larynx point and mandibular angle was 24.32 (18.8-35.78) mm and 13.55 (9.26-19.60) mm. The straight distance from carotid bifurcation to mastoid tip was 68.59 (49.48-76.94) mm. According to the vertical distance of larynx point to carotid bifurcation, the height of bifurcation of the carotid artery was consistent with the results of wain measurement (K=0.90), and the difference was statistically significant (P<0.05). (2) The distances between the point of EBSLN to medial margin of the carotid artery to carotid artery bifurcation, upper thyroid artery bifurcation, mandibular angle and mastoid process were 17.81(15.24-25.58) mm, 19.42 (17.08-29.12) mm, 20.51 (17.98-22.20) mm, 71.00 (69.00-74.50) mm in normal bifurcations. Those in the high bifurcation specimens were 6.40 (2.44-9.20) mm, 8.84(4.74-10.88) mm, 12.15(10.64-13.54), 60.90 (59.80-66.50) mm, respectively. Conclusions The position of the laryngeal prominence is fixed, which can be used as a marker for surgical incision. When the vertical distance from the larynx point to the bifurcation of the carotid artery is greater than or equal to 2.5 cm, it is highly bifurcated; the bifurcation is normal when less than 2.5 cm. In patients with normal carotid bifurcation, 1.5 cm of the carotid artery bifurcation can be used as a safety mark limit during the operation. For patients with high carotid artery, the EBSLN is almost parallel to or down the superior thyroid artery, and it should be closely attached to the bifurcation of the carotid artery and the outer membrane of the superior thyroid artery, and there is no safety margin. Key words: Carotid endarterectomy; Cervical bifurcation; External branch of superior laryngeal nerve; Laryngeal prominence

Objective: To review the surgical anatomy of the hypoglossal nerve in the neck, analyse its relationship to surrounding structures and offer landmarks to identify the nerve during carotid endarterectomy.Method: The carotid bifurcation, external carotid artery, internal carotid artery, extracranial part of the hypoglossal nerve, occipital artery, sternocleidomastoid artery and surrounding neurovascular structures were dissected and studied on 15 formalin-fixed adult cadaver heads (30 sides and 15 pairs) via a surgical microscope. Landmarks for the hypoglossal nerve and measurements of its distance from the carotid bifurcation are described. The relationship between the sternocleidomastoid artery and the occipital artery is also described.Results: The distance from the carotid bifurcation to the point at which the hypoglossal nerve crosses over the internal carotid artery was variable, ranging from 3.89 to 37.03 mm (mean, 20.95 ± 7.78 mm). The distance from the bifurcation to the point at which the hypoglossal nerve crosses over the external carotid artery ranged from 2.63 to 29.43 mm (mean, 15.33 ± 7.86 mm; Table 1). The sternocleidomastoid artery had a very characteristic course and close relationship with the hypoglossal nerve. Ascending for a short distance in a cranial direction, it crossed over the hypoglossal nerve and then descended toward the sternocleidomastoid muscle. The sternocleidomastoid artery originated from the occipital artery (33.4%), the external carotid artery–internal carotid artery junction (30%), the external carotid artery itself (30%) or even the lingual artery (6.6%).Conclusion: The relationship between the hypoglossal nerve and the carotid bifurcation is quite variable, and this explains the vulnerability of the nerve during carotid endarterectomy. The sternocleidomastoid artery is a good landmark for identifying the hypoglossal nerve. If there is exact anatomical knowledge about the relationship between the sternocleidomastoid artery and the hypoglossal nerve, the incidence of nerve injuries during carotid endarterectomy can be minimized.

During the routine dissection of the neck region of a 77 years old male cadaver in the Department of Anatomy at Bankura Sammilani Medical College, a unilateral variation in the position and course of internal and external carotid arteries was noticed on the right side of neck. The internal carotid artery was anteromedial to the external carotid artery at the site of bifurcation of the common carotid artery. Knowledge of variation in the course and relation of internal and external carotid arteries is important for surgeons to perform neck surgery and also for the radiologists to interpret carotid system imaging.