Uncommon Instance of Survival for the Hypoglossal Artery: A Detailed Account
In a recent case study, a 70-year-old woman with no known medical history presented to the emergency department with sudden-onset left-sided hemiparesis. Upon further investigation, a unique vascular variant was discovered, highlighting the importance of understanding such abnormalities in neurovascular care.
The findings in the case study were consistent with an anatomical variant, specifically a carotid-vertebrobasilar anastomosis of the persistent hypoglossal artery type. This rare embryonic vascular variant, typically originating from the posterior aspect of the cervical internal carotid artery, between the vertebral levels C1 and C3, was found to be the culprit.
The persistent hypoglossal artery is the second most common type of persistent carotid-basilar anastomosis, following the persistent trigeminal artery. It follows the path of the hypoglossal nerve, passing through an enlarged hypoglossal canal, and ultimately joins the basilar artery from below. The artery's unusual persistence and course can lead to potential complications.
The recognition of the persistent hypoglossal artery on imaging is important due to its potential to cause neurovascular complications. For instance, aneurysm formation and rupture have been associated with the artery, which may lead to subarachnoid hemorrhage or other hemorrhages, with serious neurological consequences.
Additionally, the presence of the persistent hypoglossal artery can heighten the risk of embolic stroke during vascular procedures or disease states. Surgical or vascular interventions near the artery also risk injury to cranial nerves, especially cranial nerves VII and IX–XII, which are anatomically close. This can result in neurological deficits affecting facial movement, swallowing, or tongue movement.
Moreover, the presence of a persistent hypoglossal artery can complicate head and neck surgeries and interventional procedures due to abnormal vascular anatomy, increasing risks of vascular injury and related complications.
Fortunately, the patient in the case study recovered fully within 1 hour and was discharged on secondary stroke prevention therapy and scheduled for follow-up in neurology and vascular medicine.
During early embryonic development, the neural longitudinal arteries, precursors of the vertebral arteries and basilar artery, emerge and run along the developing brainstem. If the regression of these primitive anastomoses does not occur correctly, persistent carotid-vertebrobasilar anastomoses form, making the vertebrobasilar system partially or entirely dependent on blood flow from the internal carotid artery through these anastomoses.
Other variants, such as the persistent otic artery and persistent proatlantal intersegmental artery, also connect the internal carotid artery or external carotid artery to the vertebral artery, further emphasising the complexity and variability of vascular anatomy.
Awareness of these vascular variants is crucial in neurovascular imaging and intervention planning to avoid or mitigate risks. While the persistent hypoglossal artery has an estimated prevalence of 0.02%-0.26%, understanding its potential complications can lead to improved patient care and outcomes.
In the context of the case study, the presence of the persistent hypoglossal artery, a rare neurological disorder, was found to be the culprit, leading to potential complications such as aneurysm formation and embolic stroke during vascular procedures. Early recognition of this vascular variant in health-and-wellness and medical-condition evaluations could help mitigate these risks and improve patient care in science and neurology.
