Review of the external carotid plexus: anatomy, function, and clinical manifestations

The relevance of the superior cervical ganglion for cardiac autonomic innervation in health and disease: a systematic review

PURPOSE

The heart receives cervical and thoracic sympathetic contributions. Although the stellate ganglion is considered the main contributor to cardiac sympathetic innervation, the superior cervical ganglia (SCG) is used in many experimental studies. The clinical relevance of the SCG to cardiac innervation is controversial. We investigated current morphological and functional evidence as well as controversies on the contribution of the SCG to cardiac innervation.

METHODS

A systematic literature review was conducted in PubMed, Embase, Web of Science, and COCHRANE Library. Included studies received a full/text review and quality appraisal.

RESULTS

Seventy-six eligible studies performed between 1976 and 2023 were identified. In all species studied, morphological evidence of direct or indirect SCG contribution to cardiac innervation was found, but its contribution was limited. Morphologically, SCG sidedness may be relevant. There is indirect functional evidence that the SCG contributes to cardiac innervation as shown by its involvement in sympathetic overdrive reactions in cardiac disease states. A direct functional contribution was not found. Functional data on SCG sidedness was largely unavailable. Information about sex differences and pre- and postnatal differences was lacking.

CONCLUSION

Current literature mainly supports an indirect involvement of the SCG in cardiac innervation, via other structures and plexuses or via sympathetic overdrive in response to cardiac diseases. Morphological evidence of a direct involvement was found, but its contribution seems limited. The relevance of SCG sidedness, sex, and developmental stage in health and disease remains unclear and warrants further exploration.

Stylohyoid Chain Syndrome (Eagle Syndrome) in Conjunction with Carotid Artery Dissection: A Case Report of Surgical Treatment

(1) Background: "Eagle Syndrome", also known as "stylalgia" or a "stylohyoid chain anomaly", typically manifests with ipsilateral orofacial pain, a foreign body sensation in the throat, and ear-related symptoms. Despite these common presentations, its potential association with carotid artery dissection is not widely acknowledged. (2) Methods: This article presents an extremely rare case of a patient diagnosed with an ischemic stroke in the left hemisphere, followed by the dissection of the left internal carotid artery, initially with an unidentified cause. Subsequent examinations revealed elongated left styloid processes directly compressing the dissected artery. (3) Results: After initial treatment involving pharmacological and mechanical thrombectomy, styloidectomy restored blood flow to the internal carotid artery. The patient remained symptom-free during a 12-month follow-up. (4) Conclusions: This case emphasizes the importance of considering anatomical variations within the stylohyoid chain when assessing young individuals with neurological symptoms. Furthermore, it underscores the potential benefits of early surgical intervention in reducing the morbidity and mortality associated with this condition.

Lymphoma masquerading as jaw pain, headache, and syncope: A case report

BACKGROUND

Lymphomas of parapharyngeal space often have complex manifestations, posing a diagnostic dilemma for clinicians.

CASE DESCRIPTION

A 64-year-old man sought treatment for a 4-month history of unresolving right-sided headache and jaw pain associated with syncope, all of which started with a toothache. Since the onset of pain, the patient had undergone multiple diagnostic tests with various specialists, with no pain relief. A detailed clinical and radiologic examination by an orofacial pain specialist revealed diffuse large B-cell lymphoma in the parapharynx.

PRACTICAL IMPLICATIONS

A thorough knowledge of the head and neck anatomy helps in identifying the pathophysiology of complex orofacial pain manifestations, which assists in early diagnosis and treatment.

The laryngopharyngeal nerve: a comprehensive review

The laryngopharyngeal nerve has received much less attention that the other contributions to the pharyngeal plexus i.e., glossopharyngeal and vagus nerves. Often, in descriptions and depictions, the nerve is simply labeled as the sympathetic contribution to the pharyngeal plexus. As there is such scant information available regarding this nerve, the present review was performed. Very little is found in the extant medical literature regarding the laryngopharyngeal nerve. However, based on available data, the nerve is a consistent contributory to the pharyngeal plexus and serves other adjacent areas e.g., carotid body. Therefore, a better understanding of this structure's anatomy is important for those who operate in this area. Further studies are necessary to better elucidate the true function of the laryngopharyngeal nerve.

First Bite Syndrome after Carotid Endarterectomy for High Carotid Bifurcation and Extensive Lesions: Two Case Reports and Literature Review

First bite syndrome (FBS) is an extremely rare complication of carotid endarterectomy (CEA). FBS presents with unique characteristics, development of brief and intense pain in the ipsilateral parotid region at the first bite of each meal, and improvement with subsequent mastication. Here, we report two cases of FBS following CEA. Both cases had anatomical difficulty of a high carotid bifurcation and a high cervical lesion. The lingual and facial arteries (or their common arterial trunk) branched off the external carotid artery (ECA) close to a high carotid bifurcation. The operations required exposure of the ECA distal to these two branches and the distal internal carotid artery (ICA) with a wider range of dissection for clamping the vessels. Several days or weeks after CEA, the patients developed FBS, and their meal-related pain completely resolved in the ensuing weeks. Especially in patients with a high carotid bifurcation, several branches of the ECA tend to originate from the proximal portion of the ECA, similar to octopus arms. During CEA, in these patients, dissection around the ECA and its branches in a wider range is required for exposure of each vessel and placement of the cross-clamp. These procedures can lead to injury to the external carotid nerve and plexus, possibly causing FBS. Additionally, because of the close location of the superior cervical ganglion, external carotid nerves, and distal ICA, manipulation for exposure of the distal end of a high plaque can increase the risk of injury to the cervical sympathetic nerves.