Anatomical Study of the Posterior Spinal Artery Branches to the Medulla Oblongata

Sildenafil-induced spinal cord infarction: a case report

Spinal cord infarction is a rare condition, accounting for only a small percentage of strokes. It can be classified into cervical and thoracolumbar infarctions, with various factors contributing to its occurrence. Sildenafil, a phosphodiesterase type 5 inhibitor commonly used for erectile dysfunction, has been associated with cardiovascular side effects, including transient hypotension. In this case report, we present the unusual occurrence of spinal cord infarction in a 65-year-old man who had self-administered high doses of sildenafil without a doctor's prescription. The patient experienced severe radicular pain in the lumbar region and subsequent weakness in the lower limbs. Evaluation revealed an anterior spinal cord infarction in the thoracic region, confirmed by MRI imaging. After excluding other potential causes, it was concluded that the intake of sildenafil likely led to systemic hypotension, resulting in spinal cord infarction. This case highlights the importance of considering sildenafil as a possible contributor to spinal cord infarction, particularly when used at high doses. Further studies are needed to better understand the relationship between sildenafil and vascular complications, including spinal cord infarction.

A comprehensive review of the vertebral artery anatomy

BACKGROUND

The vertebral arteries (VA) play a critical role by supplying nearly one-third of the brain's blood flow, predominantly contributing to the posterior circulation. These arteries may need to be exposed in a various cranial and cervical procedures and offers access to investigate or treat vascular lesions by endovascular means related to the posterior circulation. Given its complex anatomy, which is subject to numerous variations, and its role in supplying vital brain regions, a thorough understanding of the VA's anatomy is paramount for any related procedure.

OBJECTIVE

To provide a comprehensive overview of vertebral artery anatomy and its relevance in contemporary clinical practice.

METHODS

Dissection of the entire vertebral artery length using cadaveric specimen, combined with a comprehensive literature review.

RESULTS

The vertebral artery can be subdivided into four segments. Each of these segments has its own unique topographic anatomy with its variations, anastomoses, and significance in surgery.

CONCLUSION

As surgical and endovascular techniques continue to evolve with technological improvements, we are now more equipped than ever to manage complex lesions involving the VA. However, with its increasingly complexity comes the necessity for a deeper and more comprehensive understanding of the VA. Possessing the detailed knowledge of the VA is vital for the successful execution of any procedure involving it.

Spontaneous intracranial vertebral artery dissections presenting with subarachnoid hemorrhage

BACKGROUND

Vertebral artery dissection (VAD) is an infrequent source of subarachnoid hemorrhage (SAH), with a high mortality rate, primarily due to the risk of rebleeding both before and after medical intervention. This paper provides a comprehensive analysis of the anatomy, pathophysiology, clinical presentation, treatment strategies, and outcomes of intracranial vertebral artery dissections that result in subarachnoid hemorrhage.

METHODS

Comprehensive five-year literature review (2018-2022) and a retrospective analysis of patient records from our institution between 2016 and 2022. We included studies with a minimum of 5 patients.

RESULTS

The study incorporated ten series from the literature and 22 cases from CHUM. Key anatomical factors increasing the risk of VAD include the vertebral artery's origin from the aortic arch, asymmetry of the vertebral artery, and its tortuosity. Patients may display specific collagen and genetic abnormalities. The occurrence of VAD appears to be more prevalent in men. Those with a ruptured intracranial VAD typically show prodromal symptoms and present with severe SAH. Rebleeding within the first 24 h is frequent. While standard imaging methods are usually adequate for VAD diagnosis, they may not provide detailed information about the perforator anatomy. Treatment approaches include both deconstructive and reconstructive methods.

CONCLUSION

Ruptured VAD is a critical, life-threatening condition. Many patients have a poor neurological status at presentation, and rebleeding prior to treatment is a significant concern. Deconstructive techniques are most effective in preventing rebleeding, whereas the efficacy of reconstructive techniques needs more investigation.

Medullary branches of the vertebral artery: microsurgical anatomy and clinical significance

BACKGROUND

Since the medullary arteries are of a great neurologic and neurosurgical significance, the aim was to perform a detailed microanatomic study of these vessels, as well as of the medullary infarctions in a group of patients.

METHODS

The arteries of 26 halves of the brain stem were injected with India ink and gelatin, microdissected and measured with an ocular micrometer. Neurologic and magnetic resonance imaging (MRI) examinations were performed in 11 patients.

RESULTS

The perforating medullary arteries, averaging 6.7 in number and 0.26 mm in diameter, most often originated from the anterior spinal artery (ASA), and rarely from the vertebral (VA) (38.5%) and the basilar artery (BA) (11.6%). They supplied the medial medullary region. The anterolateral arteries, 4.8 in number and 0.2 mm in size, most often arose from the ASA and PerfAs, and nourished the anterolateral region. The lateral arteries, 2.2 in number and 0.31 mm in diameter, usually originated from the VA and the posterior inferior cerebellar artery (PICA). They supplied the lateral medullary region. The dorsal arteries, which mainly arose from the PICA and the posterior spinal artery (PSA), nourished the dorsal region, including the roof of the 4th ventricle. The anastomotic channels, averaging 0.3 mm in size, were noted in 42.3%. Among the medullary infarctions, the lateral ones were most frequently present (72.8%).

CONCLUSION

The obtained anatomic data, which can explain the medullary infarctions symptomatology, are also important in order to avoid damage to the medullary arteries during neurosurgical and neuroradiologic interventions.

Anatomic and MRI bases for medullary infarctions with patients' presentation

OBJECTIVE

There is a low incidence of the medullary infarctions and sparse data about the vascular territories, as well as a correlation among the anatomic, magnetic resonance imaging (MRI) and neurologic signs.

MATERIALS AND METHODS

Arteries of the 10 right and left sides of the brain stem were injected with India ink, fixed in formalin and microdissected. The enrolled 34 patients with medullary infarctions underwent a neurologic, MRI and Doppler examination.

RESULTS

Four types of the infarctions were distinguished according to the involved vascular territories. The isolated medial medullary infarctions (MMIs) were present in 14.7%. The complete MMIs comprised one bilateral infarction (2.9%), whilst the incomplete and partial MMIs were observed in 5.9% and 8.9%, respectively. The anterolateral infarctions (ALMIs) were very rare (2.9%). The complete and incomplete lateral infarctions (LMIs), noted in 35.3%, comprised 11.8% and 23.6%, respectively, that is, the anterior (5.9%), posterior (8.9%), deep (2.9%), and peripheral (5.9%). Dorsal ischemic lesions (DMIs) occurred in 11.8%, either as a complete (2.9%), or isolated lateral (5.9%) or medial infarctions (2.9%). The remaining ischemic regions belonged to various combined infarctions of the MMI, ALMI, LMI and DMI (35.3%). The infarctions most often affected the upper medulla (47.1%), middle (11.8%), or both (29.5%). Several motor and sensory signs were manifested following infarctions, including vestibular, cerebellar, ocular, sympathetic, respiratory and auditory symptoms.

CONCLUSIONS

There was a good correlation among the vascular territories, MRI ischemia features, and neurologic findings regarding the medullary infarctions.