Intradural lumbar radicular arteriovenous malformation mimicking perimedullary arteriovenous malformation of the conus medullaris: illustrative case

BACKGROUND Intradural radicular arteriovenous malformation (AVM) of the cauda equina is a rare entity of spinal AVMs. Because of the specific arterial supply of the conus medullaris and cauda equina, AVMs in this area sometimes present with confusing radiological features. OBSERVATIONS The authors reported a rare case of intradural radicular AVM arising from the lumbar posterior root. The patient presented with urinary symptoms with multiple flow void around the conus medullaris, as shown on magnetic resonance imaging. Digital subtraction angiography demonstrated arteriovenous shunt at the left side of the conus medullaris fed by the anterior spinal artery via anastomotic channel to the posterior spinal artery and rich perimedullary drainers. There was another arteriovenous shunt at the L3 level from the left L4 radicular artery. Preoperative diagnosis was perimedullary AVM with radicular arteriovenous fistula. Direct surgery with indocyanine green angiography revealed that the actual arteriovenous shunt was located at the left L4 posterior root. The AVM was successfully treated by coagulation of feeding branches. LESSONS Unilateral arteriovenous shunt fed by either posterior or anterior spinal artery at the conus medullaris may include AVM of the cauda equina despite abundant perimedullary venous drainage. Careful pre- and intraoperative diagnostic imaging is necessary for appropriate treatment.

Role of the Cervical Anterior Spinal Artery in the Endovascular Treatment of Vascular Diseases: Bystander, Accomplice, Victim, or Friend?

The cervical anterior spinal artery (ASA) is a very important artery arising from the intracranial vertebral artery (VA). It can play different roles in endovascular treatment (EVT) of spinal vascular diseases. The current understanding of these roles is incomplete; therefore, we performed this review. We found that cervical ASA can be involved in many spinal vascular diseases, such as arteriovenous fistula (AVF), arteriovenous malformation (AVM), and aneurysm, and can serve as a collateral channel in proximal VA occlusion. In AVF and AVM, when the cervical ASA is involved, it often plays the role of an accomplice or victim because it acts as the feeder or as a bystander that does not provide blood flow to the AVF and AVM. In cervical ASA aneurysm, the ASA is a victim. During EVT of VA aneurysms or stenoses, the cervical ASA ostia can be covered or occluded, resulting in ASA ischemia. In this situation, the ASA is a victim. In VA occlusion or the subclavian steal phenomenon, the cervical ASA can serve as a collateral channel to provide blood flow to the posterior circulation. In this case, the ASA plays the role of a friend. According to the role of the cervical ASA in spinal vascular diseases, EVT should be determined “case by case.” Most importantly, when EVT is performed to treat these diseases, the cervical ASA axis must be preserved. Therefore, understanding the role of the cervical ASA in spinal vascular diseases is crucial.

High false-negative rate of the anterior spinal artery by intercostobronchial trunk arteriography alone compared to CT during arteriography

Objectives: This study aimed to assess the frequencies of the anterior spinal arteries identified by CT during arteriography (CTA) and arteriography alone. Methods: This retrospective study included 137 vessels in 83 patients who performed both bronchial arteriography and CTA and categorized them into three groups based on the catheter tip locations: intercostobronchial trunk (ICBT), bronchial artery (BA), and intercostal artery (ICA). The frequencies of anterior spinal artery identified by CTA and arteriography alone were compared for each group. Results: ICBT, BA, and ICA groups were evaluated by CTA in 46, 79, and 12 vessels, respectively. By CTA evaluation, anterior spinal artery was identified in seven vessels (15.2%) in ICBT group, 0 in BA group, and 2 (16.7%) in ICA group. The frequencies of anterior spinal artery were significantly higher (p < 0.05) in ICBT and ICA groups than in BA group. By arteriography alone evaluation, a faint anterior spinal artery was identified in two vessels (4.3%) in ICBT group, 0 in BA group, and 1 (8.3%) in ICA group. Conclusions: Anterior spinal artery branched only from the ICBT or ICA and not from the BA in both arteriography and CTA assessments. There was high false-negative rate (71%) of the anterior spinal artery by ICBT arteriography alone assessment compared to CTA assessment. This result explains one of the reasons that spinal ischemia occurs in arteriography-negative spinal artery cases. Advances in knowledge: False-negative rate of anterior spinal artery was 71% (5/7) by intercostobronchial trunk arteriography alone assessment.

Endovascular treatment of a ruptured aneurysm arising from the proximal end of a partial vertebrobasilar duplication with a contralateral prominent persistent primitive hypoglossal artery: illustrative case

BACKGROUND Ruptured aneurysms associated with a partial vertebrobasilar duplication or a persistent primitive hypoglossal artery (PPHA) have been reported. Only rarely has endovascular treatment of ruptured aneurysms in association with both vascular variations been reported. OBSERVATIONS A 66-year-old woman experienced the sudden onset of a severe headache caused by a subarachnoid hemorrhage. Cerebral angiograms demonstrated a prominent PPHA originating from the left internal carotid artery at the C2 vertebral level and a partial vertebrobasilar duplication between the hypoplastic right vertebral artery and proximal basilar artery with a small aneurysm at the proximal end of the duplication from where the anterior spinal artery originated. The left vertebral artery was aplastic. A microcatheter was introduced into the aneurysm via the PPHA under the control of high blood flow, using a balloon-assisted technique. The aneurysm was completely obliterated with a coil. Although small cerebellar and cerebral infarcts developed during the procedure, the patient was discharged without neurological symptoms. LESSONS To avoid serious neurological complications, precise analysis of the complex vascular anatomy, including the anterior spinal artery and hemodynamics, is clinically important for endovascular therapy of cerebral aneurysms in patients with an association between a partial vertebrobasilar duplication and a PPHA.

Anterior Spinal Artery Syndrome due to Intervertebral Disc Herniation: A systematic review

Objective: Anterior spinal artery syndrome (ASAS) has been rarely reported as a complication of intervertebral disc herniation (IVDH). Precipitation factors, presentation, evaluation, treatment strategy, and degrees of recovery have not yet been well documented. Methods: Systematic review was conducted according to PRISMA guidelines to review and summarize for the qualitative synthesis of the data from reported cases of anterior spinal artery syndrome due to intervertebral disc herniation from 1980 to February 2021. Results: A total of 12 cases were reviewed, the median age was 48.5 years. Motor weakness with or without pain was the most frequent presenting symptom accompanying bowel or bladder incontinence (25%) or diminished pain and temperature sensation with spared dorsal column sensation. 40% of conservatively treated patients had complete recovery without any residual deficit. Whereas all patients who managed surgically regained fully functional status with shorter recovery intervals. Conclusion: Abrupt onset of motor weakness is a potential warning symptom of spinal cord infarction, rarely attributed to ASA compression by a herniated disc. Moreover, an accompanying diminished pain and temperature sensation with spared dorsal column sensation is further intimation. Reestablishment of blood flow may bear a favorable outcome.

Spinal arteriovenous fistula in the lipoma of the filum terminale: A report of two cases and literature review

Background: Filum terminale arteriovenous fistulas (FTAVFs) are rare and their pathogenesis remains unknown. The authors report two cases of FTAVF that arose in the lipoma of the filum terminale. Case Description: The two patients were 72 and 76 years of age, and both presented with a progressive paraparesis. The first patient had an arteriovenous fistula (AVF) located at L5 that was supplied by the anterior spinal artery originating from the left T10 intercostal artery. The second patient’s AVF at L3-4 was fed by the anterior spinal artery originating from the left T8 intercostal artery. Both patients underwent partial resection of the filum terminale at the location of the shunts. The pathological examinations revealed that both the AVFs were embedded in the adipose tissue of the filum terminale, revealing the fatty fila that were not visible in preoperative magnetic resonance images. Conclusion: Two cases of FTAVF were successfully treated by obliterating the fistulas through partial resection of the affected fatty filum terminale. The literature review revealed 13 cases of FTAVF concomitant with the lipomas of the filum terminale. Resection and histological evaluation of the filum terminale should be performed to treat and elucidate the pathogenesis of FTAVF.