Fenestration of the posteroinferior cerebellar artery: case report

OBJECTIVE AND IMPORTANCE: Fenestrations of cerebral arteries are rare, but very important to diagnose given their high association with saccular aneurysms. We present the first reported case of a fenestration of the posteroinferior cerebellar artery (PICA). CLINICAL PRESENTATION: A 62-year-old man who presented with a subarachnoid hemorrhage underwent repeated four-vessel cerebral angiography. An isolated right PICA abnormality consistent with a dissection or fenestration was revealed. INTERVENTION: The patient underwent surgical exploration of his PICA, which confirmed a PICA fenestration without an associated saccular aneurysm. The fenestration was wrapped with cotton. CONCLUSION: Our case report illustrates the novel anatomic finding of a fenestration of the PICA. Knowledge of this entity would be helpful in the differential diagnosis of a posterior fossa subarachnoid hemorrhage.     

A dissecting aneurysm of the posterior inferior cerebellar artery was reduced spontaneously during conservative therapy: case report

We report here a case of a patient with a dissecting aneurysm of the anterior medullary segment of the posterior inferior cerebellar artery (PICA) which presented with Wallenberg's syndrome. A 32-year-male presented with an unusual case of Wallenberg's syndrome due to a dissecting aneurysm of the PICA manifesting as a sensation of heaviness in the occipital region and vertigo. The occipital symptoms persisted and vertigo and vomiting developed after 6 days. Numbness developed on the left side of the patient's face, and hyperalgesia on the right side of the body. The diagnosis of Wallenberg's syndrome was based on the above findings. MRI revealed infarction of the lateral aspect of the medulla oblongata and MR angiography revealed dilatation in the proximal portion of the left PICA. Digital subtraction angiography revealed that the left vertebral artery was essentially normal, but there was a spindle-shaped dilatation in the proximal portion of the left PICA. We carried out conservative therapy at the patient's request and 3D-CTA revealed that the dissecting aneurysm was markedly reduced in size seven months after the onset. Dissecting aneurysms of the intracranial posterior circulation have been shown to be less uncommon than previously thought. However, those involving the PICA without involvement of the vertebral artery at all are extremely rare. The natural history of the dissecting PICA aneurysm was unknown, and the indication for surgical treatment of such aneurysms remains controversial. Management options are conservative treatment, open surgical treatment including wrapping, trapping, and resection with reconstruction, but almost all of the patients underwent radical treatment to prevent rupture of the aneurysm. However we had no knowledge of the risk of rupture of a PICA dissecting aneurysm presenting with ischemic symptoms. We have reviewed the well-documented 15 cases of dissecting aneurysms of the PICA reported in the literature and we discuss the management of the dissecting PICA aneurysm presenting with ischemic symptoms.     

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.     

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.     

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.     

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.     

Dissecting aneurysm of the posterior inferior cerebellar artery--a case report

The authors present a case of dissecting aneurysm of the right posterior inferior cerebellar artery (PICA) in a 47-year-old female, who suffered from mild subarachnoid hemorrhage. Right vertebral angiogram showed typical "pearl and string" sign of the PICA, but we could not fully understand the condition until a surgical exposure revealed a purple sausage-like dissecting aneurysm of the PICA. The aneurysm was wrapped with muscle pieces. Postoperatively she developed Wallenberg's syndrome, but it subsided gradually. No specific disorder concerning the mural dissection was found in this patient, except for a history of mild hypertension. This case is unusual because it affected not an arterial trunk but a small branch and we could find only one other case reported in the literature. Other formerly reported cases were of arterial trunks. The intracranial dissecting aneurysm has been known as a rare cause of cerebral infarct in children and adolescents. Infants are also affected and referred to as "infantile hemiplegia". It mainly affects one of the trunk arteries and cause a severe ischemic stroke, and surgically treatable case is rare. But as the typical angiographic findings are commonly known the number of the reported cases is increasing at an accelerating rate, and some of them are being noted to need surgical treatment because they cause subarachnoid hemorrhage. We here emphasize that not only trunk arteries but also small branch arteries can develop mural dissection, leading to subarachnoid hemorrhage. Dissecting aneurysm of a smaller artery would be milder in symptom, and would give more chance for surgical intervention.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aneurysms of the distal posterior inferior cerebellar artery--analysis of 14 aneurysms in 13 cases

Thirteen cases of distal posterior inferior cerebellar artery (PICA) aneurysms are reported here. All the aneurysms were found after a subarachnoid hemorrhage. Dissecting aneurysm, incidentally found unruptured aneurysms, and aneurysms associated with arteriovenous malformation have been eliminated from this study. Characteristics for this type of lesion are a high rate of recurrent hemorrhage and rapid death due to direct compression of the brain stem, which clearly indicates the necessity of early surgery. Attention should be paid to the fact that angiography cannot always reveal aneurysms, especially when they are located in the peripheral PICA. One should also pay attention to multiple lesions and rapid growing acute subdural hematoma as initial findings for ruptured distal PICA aneurysm. Prognostic factors for these lesions are, vasospasm, especially when the aneurysm is located proximally in the PICA, and direct compression of the brain stem due to intraventricular hemorrhage when the aneurysm is located distally. It has been suggested that the pathogenesis of this lesion could be hemodynamic stress or embryogenesis. The shape and anomalous arterial structures of the 14 aneurysms presented here tend to agree with this suggestion. Our results suggest that the pathogenesis is hemodynamic stress that had developed due to embryological and/or arteriosclerotic factors.     

Surgical management of ruptured and unruptured symptomatic posterior inferior cerebellar artery aneurysms

This retrospective study analyses the outcome of posterior inferior cerebellar artery aneurysms treated surgically. Thirteen consecutive ruptured and unruptured PICA aneurysm patients from January 1998 to January 2004 were reviewed retrospectively. The mean age was 49.1 +/- 7.4 years. Three were unruptured aneurysms and ten presented with acute subarachnoid haemorrahge. Surgery was performed immediately after completed 4 vessel angiograms using the far lateral approach. Eight were fusiform while five were saccular aneurysms. The saccular aneurysms were clipped. Treatment of the fusiform aneurysms included 3 trappings and three proximal clippings. One patient refused surgery and had endovascular occlusion of a giant PICA aneurysm. Eight out of ten (80%) operated patients needed CSF shunting for hydrocephalus. All check angiograms during follow up demonstrated adequate exclusion of the aneurysms from the circulation. None developed the PICA syndrome clinically or showed infarction on brain scans. All good grade patients recovered without neurological deficits. Our experience showed that early surgery for ruptured PICA aneurysm carries a good prognosis with low morbidity. In aneurysms that cannot be clipped, sacrifice of the PICA without revascularisation procedures in proximally located PICA aneurysms may still be feasible if the occlusion is done distal to the perforators.     

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; analysis of 15 cases]

Peripheral aneurysms of the posterior inferior cerebellar artery (PICA) are rare. The authors report 15 cases of peripheral PICA aneurysms. Twelve of the aneurysms were discovered after their rupture and two were discovered after rupture of concomitant AVM, and one was detected incidentally. As to the location of aneurysms, more than half of the aneurysms arose at the telovelotonsillar segment. One patient had 2 aneurysms on the same peripheral PICA, which were not obvious on preoperative angiography because the ruptured one was partially thrombosed. Another rare case with aneurysm located at the internal auditory meatus is also reported. The findings of CT were characteristic, namely hemorrhage in the fourth ventricle without obvious hemorrhage in the basal cisterns, or only within the cerebellar vermian cistern. This phenomenon strongly suggested the possibility of rupture of peripheral PICA aneurysms. As to the surgical results, 10 patients (71%) of the 14 patients had a good recovery, and 1 patient (7%) with nonrupture aneurysm had a fair result due to pre-existing pontine hemorrhage. Three patients (21%) died. Rebleeding occurred in 3 patients, but cerebral vasospasm occurred in only 1 patient. Consequently, as peripheral PICA aneurysms are likely to be missed, and rebleeding is an unfavorable factor, one should try to demonstrate aneurysms with angiography, by using various methods such as subtraction or magnification.     

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.     

Ruptured aneurysms of the choroidal branches of the posterior inferior cerebellar artery: a review of the literature and a case report

Aneurysms of the choroidal branches of the posterior inferior cerebellar artery (PICA) are quite rare; only seven such cases have been reported thus far. In this study, we present a very rare case of a ruptured aneurysm of a choroidal branch of the PICA; the aneurysm was exposed by splitting the vermis and resected after proximal arterial ligation. We have also undertaken a thorough review of the literature on aneurysms in choroidal branches of the PICA, focusing on the clinical presentation, etiology, radiological findings, and surgical strategies. We found that the aneurysms in our patient and the aneurysms in seven published case reports were small, and frequently associated with vascular anomalies. Intraventricular hemorrhage (IVH) in the fourth ventricle was detected in all eight cases. The outcomes of surgical treatment were generally favorable, notwithstanding the high incidence of rebleeding after rupture of distal PICA aneurysms. The recognition of predominant fourth ventricular hemorrhage should raise the suspicion of the presence of an underlying aneurysm, and digital subtraction angiograms (DSAs) should be immediately obtained in order to detect small aneurysms of the choroidal branches of the PICA.     

Multiple spontaneous dissecting aneurysms of the anterior cerebral and vertebral arteries

A 50-year-old woman presented with rare multiple dissecting aneurysms that appeared first in the anterior cerebral artery (ACA) and shortly afterwards in the vertebral artery (VA). She initially suffered sudden motor weakness in the left lower limb due to acute brain infarction. Angiography revealed diffuse string sign in the right ACA. Conservative treatment resulted in resolution of the deficits. Follow-up angiography performed 1 year later revealed recovery of the ACA stenosis. Fourteen days later, she complained of sudden headache and became comatose. Computed tomography showed diffuse subarachnoid hemorrhage. Angiography revealed a new right VA dissecting aneurysm involving the posterior inferior cerebellar artery (PICA). The orifice of the dissection was not apparent in the operative field and the dissection extended to the median. The patient underwent extracranial right VA ligation, clipping of the proximal PICA, and revascularization between the right occipital artery and distal PICA. Her postoperative course was uneventful and she was discharged without neurological deficits. VA dissecting aneurysms involving the PICA without evident orifice or extending over the median can be treated by extracranial ligation with clipping of the PICA, followed by revascularization.     

Dissecting posterior inferior cerebellar artery aneurysm presenting with subarachnoid hemorrhage right after anticoagulant and antiplatelet therapy against ischemic event

BACKGROUND: Dissecting aneurysms with initial ischemic manifestations may present with subsequent subarachnoid hemorrhage (SAH), and their treatment is controversial. This is a case report that illustrates the dilemma when dealing with an immediate post-SAH period dissecting posterior inferior cerebellar artery (PICA) aneurysm initially presenting with an ischemic event. METHODS: We present a 57-year-old man with a dissecting PICA aneurysm who had SAH right after anticoagulant and antiplatelet therapy for cerebral infarction. The aneurysm was not detected by magnetic resonance angiography performed at the time of admission. RESULTS: On admission, he was treated with both anticoagulant and antiplatelet therapy. After the SAH episode, he underwent emergent resection of the dissecting aneurysm and left OA-PICA anastomosis. CONCLUSION: If hemorrhagic transformation occurs at the site of an ischemic dissecting aneurysm, surgical or endovascular intervention should be considered immediately. Although the optimal treatment of dissecting aneurysms with ischemic onset remains controversial, anticoagulant and antiplatelet therapy should not be rejected out of hand.     

Spontaneous resolution of isolated dissecting aneurysm on the posterior inferior cerebellar artery

Summary The authors report a rare example of an isolated dissecting posterior inferior cerebellar artery (PICA) aneurysm with spontaneous resolution. A 41 year-old male suffered sudden dizziness, nausea and vomiting. An angiogram and magnetic resonance imaging (MRI) detected an isolated PICA dissection. The patient was treated conservatively and recovered without any apparent neurological deficit. MRI detected the self-resolution of the dissecting aneurysm. Dissecting PICA aneurysms, especially non-haemorrhagic lesions, have the possibility of spontaneous resolution resulting in a favorable outcome. The treatment strategy for this vascular lesion may be decided based upon neuroradiological changes on careful follow-up. Correspondence: Kojiro Korematsu MD, PhD, Department of Neurosurgery, Oita Prefectural Hospital, Bunyo 476, Oita 870-8511, Japan.     

Four cases of fusiform posterior inferior cerebellar artery aneurysms successfully treated by trapping and occipital artery-PICA bypass

Aneurysms located on the proximal portion of the posterior inferior cerebellar artery (PICA) are rare, and even rarer are fusiform aneurysms in this location. Therefore the principles of surgical management are poorly understood and still subject to debate. The management plan for these lesions is based on the proper understanding of the PICA anatomy, and particularly the origin of important perforating arteries. As many anatomic variations of PICA can be observed and the perforator's origin is sometimes in complex anatomical relations with the aneurysm, the management has to be individualized in each case. The objective of management is to exclude of the aneurysm from the circulation while preserving the perforator and distal flow. We report four cases of PICA fusiform aneurysms of the anterior or lateral medullary segments which were treated successfully with trapping of the abnormal arterial segment and distal revascularization of PICA. Trapping was adjusted to the specific anatomical circumstances in each case, preserving perforators to the maximum and revascularizing (OA-distal PICA) distal territory.     

Embolization for aneurismal dilatation associated with ruptured dissecting anterior inferior cerebellar artery aneurysm with preservation of the parent artery: case report

We report a rare case of a ruptured dissecting anterior inferior cerebellar artery (AICA) aneurysm treated by endosaccular embolization with a Guglielmi detachable coil (GDC). An 85-year-old female presented with headache. Computed tomographic (CT) scan showed subarachnoid hemorrhage and intraventricular hemorrhage in the fourth ventricule. Cerebral angiography and 3D-CT angiography revealed an aneurysmal dilatation at the anterior pontine segment of the right AICA with a diagnosis of arterial dissection. The right posterior inferior cerebellar artery (PICA) was absent and the right AICA supplied the territory normally nourished by the right PICA. The aneurismal dilatation was occluded by endosacullar embolization with preservation of the AICA. The distal AICA aneurysm is rare and only seven cases treated with endovascular embolization have been reported. In these, six cases were treated by parent artery occlusion with coil and the subsequent three cases presented with ischemic complications. Only one case was treated by endosaccular embolization with GDC. To our knowledge, this is the second report of the distal AICA aneurysm treated by endosaccular embolization with GDC. Distal AICA aneurysms are briefly discussed while reviewing the literature.     

Ruptured aneurysm at the choroidal branch of the posterior inferior cerebellar artery: a case report and review of the literature

BACKGROUND: The authors present a rare case of a ruptured aneurysm at the choroidal branch of the posterior inferior cerebellar artery (PICA). CASE DESCRIPTION: A 77-year-old female was admitted to our institute because of sudden onset of severe headache and vomiting. Radiologic examination revealed intraventricular hemorrhage caused by rupture of the aneurysm at the choroidal branch of the PICA. The fusiform aneurysm was resected after ligation via a midline suboccipital approach. CONCLUSIONS: The conclusions drawn from this experience and a review of the literature include the following: (1) the aneurysm at the branch of the PICA is frequently associated with anomalies of the vascular structure, particularly in hypoplasty of the contralateral PICA; (2) hemodynamic stress is speculated to be a causative factor of these lesions; (3) cases with hypoplasty of the contralateral PICA have the possibility of developing nonmycotic peripheral aneurysms at the branch of the PICA; (4) these aneurysms should be managed immediately because of the high risk of rebleeding.     

Distal posterior inferior cerebellar artery aneurysms: Clinical characteristics and surgical management

Summary Background. Aneurysms located on the distal posterior inferior cerebellar artery (PICA) are rare, and their underlying clinical features and surgical management are poorly understood. We report our series of 16 patients with 18 distal PICA aneurysms. Method. All patients with distal PICA aneurysms were treated between March 1996 and August 2004. We excluded all PICA aneurysms that involved the vertebral artery. Patients were analysed in the light of their clinical profiles, radiological studies, intraoperative findings and outcomes. All patients underwent non-enhanced and contrast enhanced CT scans followed by 4-vessel cerebral angiography on admission. The hemorrhagic patterns on initial CT scans were assessed using the Fisher Grading Score. The outcomes were documented using the Glasgow Outcome Scale at time of discharge and at three or twelve months follow-up. Findings. The series included 6 men and 10 women. Massive intraventricular haemorrhage was found in 13 patients with proven CT subarachnoid haemorrhage, one patient revealed SAH without intraventricular components, one presented with only intraventricular blood in the occipital horns and 3 aneurysms were found incidentally without presence of blood. Fourteen aneurysms were saccular and four were fusiform. Nine cases were associated with another cerebrovascular lesion. A lateral transcondylar or a median suboccipital approach was used to secure the aneurysms in 15 patients, either by direct clipping (14 lesions) or vessel sacrifice (3 lesions). One aneurysm was treated by an endovascular approach. At long-term follow up, an excellent or good outcome was achieved in 75% of cases. One patient died due to pre-existing cardiopulmonary complications. Conclusions. Most of our cases of ruptured distal PICA aneurysms presented with haematocephalus. These were frequently associated with another vascular abnormality and 22% were fusiform or multilobulated. These specific features require special management strategies entailing an appropriate surgical approach to the aneurysm, clipping method, haematoma removal, ventricular drainage and when suitable choice of endovascular interventions.