Aneurysm of the distal posteroinferior cerebellar artery of extracranial origin: case report

OBJECTIVE AND IMPORTANCE: We describe a very rare case involving a ruptured intracranial aneurysm at the distal posteroinferior cerebellar artery (PICA) branching from the extracranial vertebral artery. CLINICAL PRESENTATION: A 53-year-old woman experienced the sudden onset of a severe occipital headache and vomiting. Computed tomographic scanning revealed subarachnoid and intraventricular hemorrhage. Cerebral angiography of the left vertebral artery demonstrated the left PICA branching from the extracranial segment of the extracranial vertebral artery at the level of C2; a saccular aneurysm arose from the intracranial portion of the distal PICA. INTERVENTION: Via the transcondylar approach, we were able to obtain adequate visualization without retracting important structures. To avoid injury to the anomalous PICA, the aneurysm was clipped. CONCLUSION: Only four other cases of a distal aneurysm of the PICA branching from the extracranial vertebral artery have been reported in the literature. In all cases, the aneurysm originated at the intradural extracranial portion of the PICA. To our knowledge, the case presented here is the first report of a ruptured aneurysm at the level of the intracranial portion of the PICA branching from the extracranial segment of the vertebral artery.     

Bilateral mirror aneurysms at the origin of the posteroinferior cerebellar artery: case report and review of the literature

We report an exceptional case of symmetrical mirror aneurysms at the origin of the posterior inferior cerebellar arteries treated by endovascular occlusion. Questions related to a correct diagnosis and treatment at this localization are discussed.     

Intravascular papillary endothelial hyperplasia arising within a posteroinferior cerebellar artery aneurysm: case report and review of the literature

OBJECTIVE AND IMPORTANCE: Intravascular papillary endothelial hyperplasia (IPEH) is an atypical proliferation of endothelium that results in abnormal organization for thrombus formation. Intracranial IPEH is a rare entity and has not been reported to arise from within an intracranial aneurysm. Furthermore, the elapsed time during which acquired intracranial IPEH develops has not been previously documented. CLINICAL PRESENTATION: In this case report, a patient with facial and neck pain was noted to have an enhancing mass lesion lateral to the medulla in magnetic resonance imaging scans. Angiography revealed a vascular mass adjacent to the posteroinferior cerebellar artery. Normal magnetic resonance imaging and magnetic resonance angiographic findings had been obtained for the patient 29 months earlier. INTERVENTION: During surgery, a thrombosed, 2.5-cm, posteroinferior cerebellar artery aneurysm was resected and noted to contain florid IPEH. There has been no evidence of recurrence in 1 year of follow-up monitoring. A literature search revealed 13 cases of intracranial IPEH, in which recurrence was observed for incompletely resected lesions. CONCLUSION: IPEH can develop in a relatively short time, can present as a hypervascular mass lesion or within an intracranial aneurysm, and should be completely resected to prevent recurrence.     

Characteristics of distal posteroinferior cerebellar artery aneurysms

OBJECTIVE: Distal posteroinferior cerebellar artery (PICA) aneurysms are rare and have not been well investigated previously. We report our series of 24 patients with 27 distal PICA aneurysms. METHODS: All patients with distal PICA aneurysms that were surgically treated at Shinshu University Hospital and its affiliated hospitals between 1983 and 2001 were reviewed retrospectively. Data relating to clinical, radiological, and intraoperative findings were analyzed. RESULTS: In our series, distal PICA aneurysms reached an incidence of 0.28 and 0.38% of all intracranial aneurysms and ruptured aneurysms, respectively. There were 23 ruptured and 4 unruptured distal PICA aneurysms. Of these, 74.1% were saccular, 7.4% fusiform, and 18.5% dissecting aneurysms. Primarily the telovelotonsillar segment of the PICA was affected. Usually, the surgical outcome was favorable and was influenced by the obstructive hydrocephalus and the preoperative grade. It was sometimes difficult to detect the ruptured distal PICA aneurysm on the initial angiogram, and an extracranial origin of the PICA was sometimes observed. CONCLUSION: This review summarizes the presentation and outcome of a large series of 24 patients with 27 distal PICA aneurysms, and we conclude that distal PICA aneurysms are benign entities compared with vertebral artery-PICA aneurysms. Characteristics that should be considered in the treatment of distal PICA aneurysms are discussed.     

Trapping and revascularization for a dissecting aneurysm of the proximal posteroinferior cerebellar artery: technical case report and review of the literature

OBJECTIVE AND IMPORTANCE: Subarachnoid hemorrhage caused by an isolated dissection of the proximal portion of the posteroinferior cerebellar artery (PICA) is a rare problem. The optimal treatment to use for patients presenting with this clinical scenario varies and therefore is controversial in the literature. We report a patient in whom this problem was treated effectively with trapping of the diseased segment and revascularization of the PICA. We report this case to review this rare topic and to present our perspective on the indications for and the effectiveness of trapping and revascularization for proximal PICA dissections that cause hemorrhage. CLINICAL PRESENTATION: A 55-year-old man was transferred to our institution and admitted for Hunt and Hess Grade IV subarachnoid hemorrhage, which improved to Hunt and Hess Grade III after ventricular drainage. Imaging revealed the source of the hemorrhage to be a pseudoaneurysm related to the dissection of the proximal portion of the PICA. INTERVENTION: Three days after the initial bleeding episode, we operated on the patient. After the occipital artery was prepared for bypass, the diseased segment was trapped. The occipital artery-to-PICA anastomosis was then immediately performed distal to the trapped segment. CONCLUSION: On the basis of our experience, the literature regarding this topic, and the anatomy of the perforators of the PICA, we think that the best treatment for a pseudoaneurysm located within the first three segments of the PICA is trapping of the diseased segment followed by revascularization distal to the trapped segment. This approach should prevent rehemorrhage and should avoid iatrogenic ischemic complications of the brainstem.     

Surgical management of fusiform aneurysms of the peripheral posteroinferior cerebellar artery

OBJECTIVE: To describe the management and outcomes of seven patients with fusiform aneurysms of the peripheral posteroinferior cerebellar artery (PICA). METHODS: Medical records and neuroimaging studies of seven patients who underwent surgical treatment of fusiform aneurysms of the peripheral PICA were reviewed. Average follow-up time was 1.5 years, and no patient was lost to follow-up. RESULTS: All patients presented with acute subarachnoid hemorrhage, and most had acute hydrocephalus. All underwent surgery, which entailed distal revascularization in six of the seven patients. Revascularization techniques included occipital artery-PICA bypass, side-to-side PICA-PICA anastomosis, and aneurysm excision with direct end-to-end PICA reanastomosis. Outcome was good in six patients and fair in one. CONCLUSION: Fusiform, peripheral PICA aneurysms are rare lesions. Distal revascularization was used in most cases because of the uncertain adequacy of collateral supply. Careful, individualized management allows for a good outcome in the majority of cases.     

Distal posterior cerebellar artery aneurysm: case report

Vertebrobazilar aneurysms make about 15% of all intracranial aneurysms, from which one fifth belongs to aneurysms a posterior inferior cerebelli (PICA). Majority of PICA aneurysms is located in the place of separation from a.vertebralis. Aneurysms of distal part of PICA are very rare, according to literature they make 0.5 to 3% of all aneurysms. 70 years old man came to neurologist because sudden headache, pain in the neck and a feeling of stiffness followed by throwing up in stream. On the occasion of medical check up attack of spontaneous subarachnoid hemorhage was suspected. Clinical gradus according to H&H III, initial CT of endocranium showed existence of smaller intracerebellar hematoma next to lateral wall of IV ventricle and trace of blood in the very ventricle without signs of acute hydrocephalus. The seventh day after the hemorrhage angio CT was done and it showed existence of aneurysm on distal part of PICA, more specially in the televelotonzilar segment on the right. After the diagnostics supplemented with standard digital substractional angiography which confirmed nature and localization of the lesion. In the postponed procedure, and in conformity with strategy of surgical timing of aneurysms in the back circulation, patient was operated three weeks after the attack of hemorrhage. Disregarding low incidence of existence of aneurysms of distal circulation (under 1% of all in the back circulation) high level of suspicion should be present and angio CT should be done as screening method, if CT shows hemorrhage which according to localization responses to possible aneurysm.     

Traumatic aneurysm of the posterior inferior cerebellar artery: case report

We report a case of a traumatic aneurysm of the posterior inferior cerebellar artery caused by an occipital fracture. The necessity to suspect a vascular traumatic lesion when an unusual subarachnoid hemorrhage is seen on the computed tomographic scan in a case of trauma is stressed.     

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.     

Aneurysm arising from the cortical branch of the superior cerebellar artery: case report

We reported a case of a 64-year-old man who presented a subarachnoid hemorrhage due to rupture of an aneurysm arising from the cortical branch of the superior cerebellar artery (SCA) at the junction of the superior vermian branch and the hemispheric branch. Eight days after the rupture, neck clipping of the aneurysm was performed successfully using the occipital transtentorial approach in a prone position, and the patient's postoperative course was uneventful. This rare case of aneurysm arising from the cortical branch of SCA was discussed with a review of literature.     

Distal aneurysms of the superior cerebellar artery and posterior inferior cerebellar artery feeding an associated arteriovenous malformation: case report.

The authors report a case of two distal aneurysms of the cerebellar arteries, one arising from the vermian branch of the posterior inferior cerebellar artery, the other arising from the hemispheric branch of the superior cerebellar artery, and both feeding an associated arteriovenous malformation (AVM). The aneurysm of the distal posterior inferior cerebellar artery was considered the source of a cerebellar hemorrhage because of the location of a hematoma in the cerebellar vermis. The life-threatening hematoma was evacuated in an emergency operation 6 hours after the acute onset of symptoms. The cerebellar aneurysms and the AVM were clipped or extirpated successfully after the patient's condition improved. The association of two rare types of aneurysms with an AVM strongly supports the theory that increased hemodynamic stress derived from the AVM plays an important role in aneurysm formation. The authors think that one should operate on the symptomatic lesion first or both the aneurysm and the AVM in the same operative procedure.     

Multiple peripheral aneurysms of the posterior inferior cerebellar artery associated with a cerebellar arteriovenous malformation: case report

The authors describe a rare case of multiple peripheral aneurysms of the posterior inferior cerebellar artery found in association with a midline cerebellar arteriovenous malformation. Successful trapping of the aneurysms and excision of the arteriovenous malformation was accomplished with an excellent clinical result. The literature concerning aneurysms of the posterior inferior cerebellar artery, cerebellar arteriovenous malformations, and combined intracranial vascular abnormalities is discussed.     

Traumatic aneurysm of the superior cerebellar artery: case report and review of the literature

Less than 10% of the 250 reported cases of traumatic intracranial aneurysms have involved the posterior circulation. Traumatic aneurysms of the superior cerebellar artery are extremely rare, with only three cases previously reported. This is the first report of a traumatic superior cerebellar artery aneurysm in which the diagnosis was suggested by computed tomographic scan. The potential for a good outcome suggests the value of early angiography when the history and diagnostic imaging studies suggest the possibility of a traumatic aneurysm.     

Tandem bypass: occipital artery to posterior inferior cerebellar artery side-to-side anastomosis and occipital artery to anterior inferior cerebellar artery end-to-side anastomosis--a case report

A unique example of posterior fossa revascularization is presented. A tandem bypass was performed by anastomosing the midoccipital artery to the posterior inferior cerebellar artery in a side-to-side fashion followed by anastomosis of the distal occipital artery to the anterior inferior cerebellar artery in an end-to-side fashion. The operation was designed to revascularize two separate vascular territories that were isolated in a patient thought to have an extremely compromised posterior circulation. The patient is doing well and is asymptomatic 3 years postoperatively.