Development of unusual collateral channel from the posterior meningeal artery after endovascular proximal occlusion of the posterior inferior cerebellar artery

A 38-year-old man presented with a dissecting aneurysm of the left proximal posterior inferior cerebellar artery (PICA) manifesting as Wallenberg's syndrome. The patient was treated by endovascular occlusion of the aneurysm and parent artery. Immediately after the treatment, the PICA territory was supplied by collateral circulation via the ipsilateral anterior inferior cerebellar artery. Seven days later, endogenous revascularization of the distal PICA territory had occurred via collateral circulation from the posterior meningeal artery (PMA). This unusual collateral circulation was thought to occur through a pre-existing anastomotic channel between the primitive vessels of the PICA and the PMA during subclinical hypoperfusion of the distal PICA territory. This unusual case demonstrates the potential for delayed development of collateral circulation from the PMA to the PICA territory.     

Ruptured aneurysm at an anastomotic artery extending from the vertebral artery to the posterior inferior cerebellar artery: a case report

A 51-year-old hypertensive man presented with subarachnoid haemorrhage. He had a past history of cerebellar infarction due to occlusion of the right posterior inferior cerebellar artery (PICA) 4 years earlier. Digital subtraction angiography showed a saccular aneurysm above an arterial loop extending from the vertebral artery to the distal part of the PICA, reminiscent of peripheral PICA branches. We performed aneurysmal neck clipping with excellent outcome. Aneurysms at anastomotic arteries are extremely rare and can result from increased haemodynamic stress. We report the first case of a ruptured aneurysm at an anastomotic artery in the posterior circulation territory.     

Peripheral aneurysms of the posterior inferior cerebellar artery

Nonmycotic peripheral posterior inferior cerebellar artery (PICA) aneurysms are rare. The authors report six cases of peripheral PICA aneurysm. Two of these are unusual; one was fusiform and another was a double aneurysm arising from the peripheral PICA. The previously reported 40 cases of peripheral PICA aneurysm are reviewed.     

Posterior inferior to posterior inferior cerebellar artery anastomosis combined with trapping for vertebral artery aneurysm. Case report

A case is presented in which a giant intracranial vertebral artery aneurysm gave rise to an associated ipsilateral posterior inferior cerebellar artery (PICA) from its waist. Proximal vertebral artery ligation at C-1 was achieved. The aneurysm filled from the opposite vertebrobasilar junction. Direct intracranial trapping of the right vertebral aneurysm was followed by successful anastomosis of the proximally sectioned right PICA to the adjacent left PICA in an end-to-end fashion.     

Ruptured aneurysm of a posterior inferior cerebellar artery communicating artery. Case report and histological findings

A hypertensive 60-year-old man presented with a rare aneurysm arising from the posterior inferior cerebellar artery (PICA) communicating artery, manifesting as subarachnoid hemorrhage with intraventricular hemorrhage. Angiography showed a small aneurysm arising from a fine and tortuous artery interconnecting the bilateral vermian branches of distal PICAs. The right PICA was absent and its vermian territory was supplied by the left PICA through this communicating artery. The right anterior inferior cerebellar artery was also connected to the vermian branch of the right PICA. At surgery, a reddish and apparent fusiform aneurysm was noted at the top of the arterial loop under the cerebellar vermis. Microsurgical trapping and removal of the aneurysm was performed without complication. Histological examination demonstrated typical findings of a true aneurysm. Only four previous cases of aneurysm of the communicating artery between the bilateral distal PICAs have been reported. In all five reported cases including ours, the PICA communicating artery contributed to the collateral blood supply of the contralateral vermian territory based on vascular anomalies. Hemodynamic stress and congenital vulnerability may have caused this aneurysm. Trapping is suitable to treat this precarious aneurysm if other collateral vessels supply the contralateral vermian territory.     

Treatment of vertebral artery aneurysms with posterior inferior cerebellar artery-posterior inferior cerebellar artery anastomosis combined with parent artery occlusion

BACKGROUND: In patients with aneurysms that involve the origin of the posterior inferior cerebellar artery (PICA) and require occlusion of the vertebral artery (VA), revascularization of the PICA is commonly performed. We present six patients with dissecting VA aneurysms who underwent PICA-PICA anastomosis combined with parent artery occlusion. METHODS: After a lower lateral suboccipital craniectomy and partial resection of the jugular tubercle, anastomoses were performed in a side-to-side fashion at the posterior medullary segment of the PICA. The VA was subsequently occluded by clipping proximal and distal to the aneurysm, and the PICA was occluded by clipping distal to the aneurysm. RESULTS: Postoperative cerebral angiography demonstrated patency of the anastomosis and regression of the aneurysm in five of six patients. The remaining patient experienced hemorrhage from contralateral VA dissection and subsequently died. One patient experienced myopathy of the lower extremities secondary to intraoperative fixed board compression and developed permanent lower extremity muscular weakness. The remaining four cases experienced no new neurologic deficits. CONCLUSION: PICA-PICA anastomosis is a useful procedure for reconstruction of the PICA when parent vessel occlusion or trapping is necessary to exclude a VA aneurysm involving the origin of the PICA.     

Clip reconstruction for a case of peripheral posterior inferior cerebellar artery aneurysm: case report.

The authors report an unusual surgical treatment for an aneurysm on the left peripheral posterior inferior cerebellar artery (PICA). The computed tomographic scan showed subarachnoid haemorrhage and a haematoma in the left cerebellar region close to the fourth ventricle. The 3D CT angiography demonstrated an aneurysm on the left peripheral PICA which was confirmed on four-vessel angiography. The aneurysm was approached through a posterior suboccipital craniotomy and the PICA was reconstructed with multiple clips. The literature concerning peripheral PICA aneurysms and their treatment is reviewed and discussed.     

Giant peripheral aneurysm of the posterior inferior cerebellar artery treated with excision and end-to-end anastomosis

A patient with a giant aneurysm arising from the tonsillomedullary segment of the posterior inferior cerebellar artery (PICA) presented with clinical and computed tomography findings suggestive of spontaneous cerebellar hemorrhage. Magnetic resonance imaging led to arteriography and the correct diagnosis. Lack of a clippable neck on the aneurysm and its location proximal to the choroidal point prompted treatment by excision of the aneurysm and end-to-end anastomosis of the PICA. No neurological deficit resulted from the procedure.     

A "PICA communicating artery" aneurysm: case report.

We present an unusual case of an aneurysm of the distal posterior inferior cerebellar artery (PICA). The aneurysm was associated with a unilateral PICA that supplied both cerebellar hemispheres and arose from an anastomotic vessel to the contralateral circulation, a branch of the contralateral PICA. Such an aneurysm has not been reported previously. The associated of vascular anomalies with aneurysms of the PICA is discussed.     

Multiple,peripheral aneurysms of the anterior inferior cerebellar artery

Summary In this case report, a 49-year-old woman developed subarachnoid hemorrhage in the right cerebellopontine angle cistern and blood into the fourth ventricle from a ruptured peripheral aneurysm of the anterior inferior cerebellar artery (AICA) located at the meatal loop. Concomitantly, a contralateral peripheral aneurysm was found in the posterior inferior cerebellar artery (PICA). A second peripheral aneurysm, not identified by previous angiography, was found in the caudomedial branch of AICA. We describe this diagnostic dilemma, management, and review the clinical presentation and location of 84 other peripheral AICA aneurysms reported in the literature.     

Aneurysm of the distal posterior inferior cerebellar artery originating from the extracranial and extradural vertebral artery

A 42-year-old woman presented with a ruptured aneurysm of the distal posterior inferior cerebellar artery (PICA), which had a rare extracranial and extradural origin. Medial suboccipital craniectomy and C-1 laminectomy were performed. The aneurysm had adhered to the right cerebellar tonsil, but was successfully clipped without difficulty. Intraoperatively, the PICA origin was recognized in the extracranial and extradural space between the dorsal roots of the C-1 and C-2 nerves. The origin of the PICA from the vertebral artery (VA) may occur at any portion of the VA from the site of penetration of the dura to the vertebrobasilar junction, but an extradural origin is uncommon. A ruptured aneurysm of the PICA branching from the VA at a site proximal to the vertebrobasilar junction and below the foramen magnum may be overlooked by three-vessel angiography if the contrast medium cannot reflux to the contralateral PICA origin.     

Bilateral mirror posterior inferior cerebellar artery aneurysms: diagnostic caveat on catheter angiography

Only three definitive cases of bilateral mirror proximal posterior inferior cerebellar artery (PICA) aneurysms have ever been reported. A fourth example is presented where each PICA aneurysm remained angiographically occult on contralateral vertebral artery angiography despite retrograde filling of the parent vessel PICA. Implications for clinical practice are discussed.     

A growing aneurysm of the posterior inferior cerebellar artery complicated with cerebellar infarction: A case report

Introduction and importanceHereby we describe an instructive patient with cerebellar infarction and a growing aneurysm at the posterior inferior cerebellar artery (PICA), which was not a true cause of infarction.Case presentationA 50-year-old female presented with dizziness and posterior neck pain at our hospital (Mitaka city, Tokyo, Japan). Diffusion weighted magnetic resonance (MR) images showed cerebellar infarction in the left PICA territory and MR angiography study showed an aneurysm at the origin of the left PICA, which grew in 2 weeks. Since we considered cerebellar infarction was caused by thrombosis from the aneurysm, trapping of the PICA and occipital artery-PICA bypass was performed to prevent recurrent cerebellar infarction and rupture of the aneurysm by neurosurgeons. During the operation, dissection was observed at the distal PICA, which was diagnosed to be the true cause of cerebellar infarction. By the follow-up for 12 months at an outpatient, there was no recurrence of cerebral infarction.Clinical discussionA specimen of the artery showing the findings of dissection was not obtained, and the pathological diagnosis could not be made. It would be controversial whether a surgical procedure presented here was the most optimal.ConclusionThis is a first reported case of growing aneurysms and cerebral infarction due to arterial dissection. Even if cerebral infarction is accompanied by growing aneurysms, arterial dissection should be included in the differential diagnoses of a cause of infarction. Posterior cervical pain can be a clue for early appropriate diagnosis in such a case.     

Distal aneurysm of the posterior inferior cerebellar artery--report of 3 cases

The incidence of posterior fossa aneurysm is reported to be 4-15% of all intracranial aneurysms in large series. Most aneurysms of the posterior inferior cerebellar artery (PICA) arise at the origin of the PICA. However, aneurysms of the distal part of the PICA have only rarely been described. This report presents three cases of distal PICA aneurysm with subarachnoid hemorrhage. Two aneurysms were located in the superior retrotonsillar segment of the PICA in two cases, and another was located in the tonsillohemispheric branch in one case. Obliteration of these aneurysms was comparatively easily done by bilateral suboccipital craniectomy. Computerized tomography (CT) was done in two cases. CT scan of the second case revealed a hematoma in the cerebellar vermis, and that of the third case revealed hemorrhage in the fourth and third ventricles. These findings seem to be common in subarachnoid hemorrhage of this lesion and may suggest the rupture of distal PICA aneurysm.     

Infra-posterior inferior cerebellar artery aneurysm arising after occlusion of the ipsilateral vertebral artery--case report.

An 85-year-old woman had subarachnoid hemorrhage due to rupture of a very rare left infra-posterior inferior cerebellar artery (PICA) aneurysm, a saccular aneurysm located proximally at the junction of vertebral artery (VA) and PICA. Right vertebral angiography demonstrated the aneurysm since the left VA was occluded in the extracranial portion. The aneurysm projected in the opposite direction to common VA-PICA aneurysms. The angiographical and intraoperative findings imply this rare aneurysm resulted from the hemodynamic changes caused by the VA occlusion. Detailed exploration of angiography is emphasized to detect such rare aneurysms among the diversity of hemodynamic patterns in elderly patients with subarachnoid hemorrhage.     

Posterior inferior cerebellar artery (PICA) aneurysm presenting with SAH and contralateral crural monoparesis: a case report.

A patient with contralateral monoparesis of the leg due to subarachnoid hemorrhage (SAH) from an aneurysm of the first posterior inferior cerebellar artery (PICA) segment is reported. The monoparesis may well be associated with the close anatomical relationships between the site of the aneurysm and the PICA blood supply of the corticospinal fibers to the contralateral leg.     

Dissecting aneurysm of the posterior inferior cerebellar artery--studied by serial angiography]

We report the case of a 34-year-old male with cerebellar hemorrhagic infarction caused by a dissecting aneurysm of the left posterior inferior cerebellar artery (PICA). The patient suffered from a headache and vomiting for two days and was transferred to our hospital with sudden deterioration of consciousness. On admission, he was semicomatose. A CT scan revealed hemorrhagic infarction in the left cerebellum and upward herniation. The emergency operation for posterior fossa decompression was performed. Postoperatively, his consciousness level improved promptly and he had no neurological deficits except for slight gait disturbance. The first vertebral angiography was performed on Day 27. It showed a sausage-like dissecting aneurysm of the left distal PICA. We planned conservative therapy with careful observation because of there being no indication for an operation. Serial angiography was performed and demonstrated the regression of the dissecting aneurysm on Day 258. Dissecting aneurysms of the distal PICA are rare and their natural history is not well understood. Conservative therapy for vertebrobasilar dissecting aneurysms has often been reported. We suggest that conservative therapy with serial angiography is the treatment of choice especially for ischemic-type dissecting aneurysms. We review 17 cases of dissecting aneurysm of the distal PICA in this study.     

Intraventricular hemorrhage due to aneurysms of the distal posterior inferior cerebellar artery. Report of three cases

Three cases of ruptured aneurysm of the distal posterior inferior cerebellar artery (PICA) presenting with isolated intraventricular hematoma are reported. All of the aneurysms originated from the lateral medullary segment of the PICA and ruptured into the lateral recess of the fourth ventricle. The diagnosis of distal PICA aneurysm should be considered if isolated intraventricular hematoma is found without obvious parenchymal hemorrhage or subarachnoid blood in the basal cisterns. Complete vertebral arteriography is a requisite for the recognition of this condition. The outcome in patients with these aneurysms should be good if surgical repair is performed before rebleeding occurs.     

Successful clipping of a distal posterior inferior cerebellar artery aneurysm located on the anterior surface of the medulla oblongata--case report

A 55-year-old male presented with a ruptured distal posterior inferior cerebellar artery (PICA) aneurysm manifesting as subarachnoid hemorrhage. Angiography demonstrated a saccular aneurysm arising from the lateral medullary segment of the left PICA and located on the medial side of the left vertebral artery (VA) and the anterior surface of the medulla oblongata. A transcondylar fossa approach was used to ensure a sufficient operating field and to obtain adequate visualization of the aneurysm, the parent artery, and the perforating arteries to the medulla oblongata. The aneurysm dome protruded medially at the hairpin curve, and was located on the medial side of the left VA and on the anterior surface of the medulla oblongata. There was no vessel branches in the vicinity of the aneurysm. The aneurysm was successfully clipped with minimum retraction of the cerebellar hemisphere and medulla oblongata. Distal PICA aneurysms can be located at various sites in the posterior fossa. The exact location of the aneurysm must be established to select the best surgical approach.