Challenges in the Management of a Ruptured Bihemispheric Posterior Inferior Cerebellar Artery Aneurysm

Resection of ruptured aneurysm associated with bilateral anomalous posterior inferior cerebellar anastomotic arteries: case report and review of literature

Introduction

Aneurysms on the posterior inferior cerebellar artery (PICA) may not be the major part of intracranial aneurysm. Especially, an aneurysm located on the bilateral posterior inferior cerebellar anastomotic artery has abnormal anatomical characteristics in the vessel wall and then causes stroke including subarachnoid hemorrhage. This case report explores the direct resection of a ruptured aneurysm associated with the bilateral anomalous anastomotic artery of PICA.

Methods

The case report discusses a 53-year-old woman who suffered from sudden severe headache and vomiting for more than 3 h admitted to our hospital. Emergency computed tomography (CT) revealed subarachnoid hemorrhage (SAH) in the third and fourth ventricles. Preoperative 3 Dimensions-digital subtraction angiography (3-D DSA) indicated a ruptured aneurysm located on the bilateral posterior inferior cerebellar anastomotic artery. Postoperative pathological findings indicated the characteristics of parent artery PICA and control aneurysm. The authors performed an overview of PICA aneurysms with anomalous variation in the Pubmed, Web of Science, and Medline databases. The search was until 1 August 2023. Related terms "posterior inferior cerebellar artery" And "aneurysm" AND "anatomical variants" were used to search the review. The reasons for anomalous variation anastomosis between bilateral PICAs were analyzed.

Results

The aneurysm was resected successfully. Post-operative 3-D DSA revealed the disappearance of the aneurysm. The vessel wall of anastomotic PICA showed neovascularized hyperplasia, abnormal arrangement of smooth muscle, CD31+ endothelial cells, and SMA+ smooth muscle cells. In contrast, when it came to aneurysm, the wall at the location of the fracture thinned, which could be used to explain that the local nodular protrusion was formed and CD31+ endothelial cells existed. No neurological deficits were found at her 1-year follow-up visit (mRS score of 0).

Conclusion

Direct resection of ruptured aneurysm associated with bilateral anomalous posterior inferior cerebellar anastomotic arteries was an effective treatment and careful consideration of the anatomical characteristics concerning the interesting aneurysm and the variant PICA was critical for sate treatment. Also, the literature on the lesion was reviewed.

Comparison of stereotactic aspiration surgery and conventional treatment for primary brainstem haemorrhage

OBJECTIVE

To explore the effect of stereotactic aspiration surgery and conventional treatment for primary brainstem haemorrhage.

METHODS

The clinical data of 137 patients with primary brain stem haemorrhage (haematoma volume > 3 ml) from August 2014 to August 2022 at the First Hospital of Hebei Medical University were reviewed. Sixty-five patients were treated with stereotactic haematoma aspiration, and 72 patients were treated with conventional therapy. We followed up on patient survival after 30 days and the recovery of neurological function after 90 days. The recovery of neurological function was evaluated by the modified Rankin Scale (mRS) 90 days after treatment. The mortality and neurological recovery rates of the two treatments were compared and analysed.

RESULTS

There was a significant difference in the 30-day mortality rate between the two treatment groups (p < 0.05). There was a significant difference in neurological function improvement after 90 days between the two treatment groups (P < 0.05). There was no significant difference between stereotactic aspiration and routine treatment in the prognosis of primary brainstem haemorrhage patients at 90 days after treatment (P > 0.05).

CONCLUSION

Stereotactic aspiration surgery for primary brain stem haemorrhage can significantly reduce mortality and improve the neurological function of some patients.

Successful endovascular treatment of a ruptured bihemispheric posterior inferior cerebellar artery aneurysm: illustrative case

BACKGROUND

Normal posterior inferior cerebellar artery (PICA) anatomy is highly variable, but bihemispheric PICA crossing the midline to supply the vascular territory of bilateral cerebellar hemisphere is rare. Herein, the authors reported a rare case of ruptured aneurysm that was associated with bihemispheric PICA and successfully treated endovascularly.

OBSERVATIONS

A 46-year-old woman presented with sudden headache and loss of consciousness because of an intraventricular hemorrhage due to a ruptured aneurysm that was associated with the bihemispheric PICA. Angiography revealed that the aneurysm was located at the bifurcation between the bihemispheric PICA and the bilateral distal PICA. The ruptured aneurysm was successfully occluded using coil embolization, which preserved the parent artery with no procedural-related complication.

LESSONS

To the best of the authors’ knowledge, this was the first report of a ruptured aneurysm associated with bihemispheric PICA being successfully treated endovascularly. Aneurysm formation may be accelerated by hemodynamic stress and vascular fragility. For neurosurgeons and neurointerventionalists, it is important to understand the anatomical variation of PICA, especially bihemispheric PICA, which is a potential risk factor for a fatal stroke.

Dissecting distal cerebellar artery aneurysms: options beyond a parent vessel sacrifice

Parent vessel occlusion (PVO) is the conventional endovascular treatment (EVT) for dissecting distal cerebellar artery aneurysms (DCAA). The associated ischemic sequelae are often well-tolerated. However, at the outset, the magnitude of this risk is uncertain. Meanwhile, non-PVO endovascular treatments (EVT) are deemed to provide incomplete protection from a rebleed. This study reviews our experience in the management of dissecting DCAA with emphasis on the effectiveness of parent vessel-preserving endovascular strategies as compared to PVO. Our institutional database was reviewed for all the dissecting DCAA aneurysms treated by endovascular means between Nov 2015 and Oct 2018. Their clinical presentations, imaging findings, EVT techniques, and clinical outcomes were retrospectively evaluated. Eighteen dissecting DCAA were identified: 13 in the posterior-inferior cerebellar artery (PICA), 3 in anterior-inferior cerebellar artery (AICA), and 2 in superior cerebellar artery (SCA). Median patient age was 61 years (range 40-86; average 60.7 years) with a 5:1 female predominance. Nine (6 in the PICA and 3 in the AICA) patients were managed by parent vessel-preserving strategies (6 with isolated endosaccular coiling and 3 with telescoping stents) while the remaining 9 (7 in the PICA and 2 in the SCA) were treated by PVO.The frequency of early rebleed was the same (11%) in both the treatment arms. One patient from the PVO arm suffered an extensive cerebellar infarct that mandated decompressive craniectomy and adversely affected her recovery. There were no such complications in patients treated with parent vessel-preserving strategies. No recurrence/rebleed was encountered in the 3 aneurysms secured using telescoping stents. Overall, excellent clinical outcomes (mRS of 0 and 1) were sparsely seen in the patients who had PVO (89 vs 23%). In dissecting DCAA, aforedescribed, parent vessel-preserving strategies are as effective as the more frequently used option of PVO in preventing an early rebleed. However, these are technically challenging, may be feasible in a smaller proportion of patients, and would need meticulous imaging follow-up in the acute period. When successfully implemented, these strategies can deliver excellent clinical outcomes and eliminate the uncertain risk of ischemic complications associated with PVO.