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.     

Extracranial posterior inferior cerebellar artery aneurysm causing isolated intraventricular hemorrhage: a case report

The authors report the unusual case of an aneurysm arising on an extracranial loop of the left posterior inferior cerebellar artery (PICA). The computed tomographic scan showed an isolated hemorrhage in the lateral ventricles, and the lesion was recognized 1.5 cm below the foramen magnum at the level of the atlas. The literature concerning peripheral PICA aneurysms is reviewed and the clinical and radiological features of these lesions are discussed. A tendency for subarachnoid bleeding from distal PICA aneurysm ruptures to spread into the ventricular system is suggested. The diagnosis of distal PICA aneurysm should also be considered in cases of isolated intraventricular hemorrhage without obvious parenchymal or subarachnoid hemorrhage. The need for four-vessel angiography when studying patients suffering from a subarachnoid hemorrhage is stressed.     

Distal anterior choroidal artery aneurysm in a patient with moyamoya disease: case report

OBJECTIVE AND IMPORTANCE: Distal anterior choroidal artery (AChA) aneurysms in moyamoya disease are rare, with few surgically verified reported cases. CLINICAL PRESENTATION: We report a rare case of distal AChA aneurysm associated with moyamoya disease in a 48-year-old man who presented with vomiting and severe headache. Computed tomographic scans revealed an intracerebral hematoma in the right temporoparietal lobe and a diffuse intraventricular hemorrhage. INTERVENTION: The hematoma was removed via computed tomography-guided stereotactic aspiration and ventricular drainage. Cerebral angiography showed a saccular aneurysm located at the distal branch of the right AChA. By means of magnetic resonance imaging, a small signal void lesion was detected in the periventricular area lateral to the trigone of the right lateral ventricle. The aneurysm was accurately accessed via a parietal cortical incision by use of magnetic resonance imaging-guided stereotactic localization. The aneurysm was successfully resected after undergoing trapping of the parent artery, and when the patient was discharged, he had no evidence of neurological deficit. The aneurysm was histologically verified to be a true aneurysm. CONCLUSION: Direct surgery should be considered in cases of ruptured distal AChA aneurysms located in the periventricular or intraventricular regions.     

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.     

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.     

Multiple aneurysms of the PICA communicating artery: a case report

A case with unusual type of aneurysms in the distal posterior inferior cerebellar artery (PICA) is reported here. Though only two cases with a single aneurysm of the PICA communicating artery have been reported previously, the present case is the first one with multiple aneurysms in the PICA communicating artery. A 61-year-old woman with a sudden onset of severe headache, vomiting and unconsciousness was transferred to our hospital. CT scan revealed a hematoma in the fourth, third, and lateral ventricles, and a mild subarachnoid hemorrhage at the posterior fossa. Cerebral angiogram showed the right PICA supplying the hypoplastic left PICA territory through an anastomotic vessel. Two small aneurysms were seen at the tips of hairpin curves of an anastomotic vessel, "the PICA communicating artery". Suboccipital craniotomy was performed, and the ruptured aneurysm was clipped and the unruptured one was wrapped with cotton-sheet. After the operation, her clinical recovery went well and she was discharged on foot.     

Distal posterior inferior cerebellar aneurysms--report of 12 cases.

The authors review 12 cases of distal posterior inferior cerebellar artery (PICA) aneurysm. Nine of the aneurysms were discovered after their rupture and three were incidentally detected. Seven (78%) of the nine ruptured aneurysms rebled, leading in four cases to coma and respiratory arrest. Computed tomography revealed intraventricular hematomas, mainly in the fourth ventricle, and a subarachnoid clot at the cisterna magna. In five of the nine cases involving aneurysm rupture, radical surgery was performed. The remaining four, whose clinical status was poor, were treated conservatively and subsequently died. Two patients were rendered partially dependent as a result of perioperative complications. A high incidence of rebleeding is characteristic of ruptured distal PICA aneurysms, and for this reason the prognosis for these patients is rather poor.     

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.     

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.     

Multiple aneurysms of the distal posterior inferior cerebellar artery with recurrent hemorrhage undetectable on preoperative neuroradiological findings: case report

We report a rare case of multiple aneurysms of the distal posterior inferior cerebellar artery (PICA) associated with recurrent hemorrhage undetectable on preoperative neuroradiological findings. A 68-year-old woman was admitted to our hospital in April, 2003 because of a sudden onset of headache, back neck pain and nausea. CT scan at the time of admission showed a hematoma in the 4th & 3rd ventricles, and a mild subarachnoid hemorrhage (SAH) in the basal, right ambient & quadrigeminal cisterns. She had had a similar history of previous intraventricular hemorrhage and SAH in October, 2001. Three-dimensional CT angiograms and left vertebral angiograms performed at that time revealed an irregular vascular lesion at the tonsillomedullary segment (TMS) of the left PICA. However, the final diagnosis was unclear. Left vertebral angiograms at the time of the 2003 admission revealed an irregular vascular lesion in the same region more clearly and the size of aneurysmal dilatations had increased considerably. So, preoperative diagnosis of an irregular vascular lesion at the TMS of the left PICA (distal PICA aneurysm was not ruled out) was based on the above neuroradiological findings. The patient was surgically treated through the suboccipital approach. The TMS of the left PICA had made a difficulty loop formation was observed. Five distinct aneurysma were found on the TMS of the left PICA. To prevent bleeding, the ruptured aneurysm & three unruptured aneurysms were clipped and the residual unruptured one was wrapped with Bemsheets. Postoperative left vertebral angiograms demonstrated neither clipped aneurysms nor occlusive findings at the TMS of the PICA. The patency of the PICA was preserved. The postoperative course was uneventful and the patient was discharged without new neurological deficits. There has been no rebleeding during the one year since surgery. The 23 reported cases of multiple aneurysms of the distal PICA including our case were reviewed and their neuroradiological and clinical features are discussed.     

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 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.     

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.     

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.     

Far lateral suboccipital approach for the treatment of proximal posteroinferior cerebellar artery aneurysms: surgical results and long-term outcome

OBJECTIVE: Proximal posteroinferior cerebellar artery (PICA) aneurysms are challenging to treat surgically, with high reported perioperative complication rates. We describe the perioperative course and long-term clinical outcomes obtained via a far lateral suboccipital approach in 20 consecutive proximal PICA aneurysms. METHODS: Data were collected prospectively on the first 20 proximal PICA aneurysms treated surgically by a single surgeon (ESC) between December 1997 and April 2003. All aneurysms were clipped via a far lateral approach. Patients with unruptured aneurysms were assessed at 3 and 12 months after surgery. For all subarachnoid hemorrhage patients, a battery of outcome tests was performed at 3- and 12-month intervals. Outcomes were then compared with those of a contemporaneously managed population of ruptured right-sided posterior communicating artery aneurysms. RESULTS: The far lateral suboccipital approach achieved adequate exposure in all cases. There were no intraoperative complications or intraoperative aneurysm ruptures. All patients with unruptured aneurysms were fully functional at long-term follow-up. At 3 months of follow-up, 93% of the subarachnoid hemorrhage patients achieved a Glasgow Outcome Scale score of 1 to 2. At 12 months of follow-up, 92% achieved a Glasgow Outcome Scale score of 1 to 2. Compared with the patients with a ruptured right-sided posterior communicating artery aneurysm, no difference could be found in quality of life or activities of daily living at either time point. CONCLUSION: The favorable outcomes and low postoperative morbidity in this subset of patients argues that clipping via this approach be considered a first-line therapeutic option. When performed in this manner, PICA aneurysm surgery seems to have no greater morbidity than right-sided posterior communicating artery aneurysm surgery.     

Distal anterior choroidal artery aneurysms

BACKGROUND: Distal AChoA aneurysms are quite rare. Only 12 operated cases have been reported in the English medical literature. Treatment of these aneurysms is also difficult because of their deep location, small size, and angioarchitecture. METHODS: The authors report 2 additional patients with aneurysms, arising from the distal AChoA and located within the temporal horn of the lateral ventricle. In the first patient, the aneurysm could also be visualized with CTA, which is the first demonstration in the literature. RESULTS: The aneurysms were explored and resected via a transtemporal/ventricular approach in both patients. One patient was discharged as neurologically intact and the other died because of severe vasospasm. CONCLUSIONS: The conclusions drawn from our experience and a comprehensive review of the literature include the following: (1) A distal AChoA aneurysm should be considered in patients with isolated medial temporal intracerebral hematoma with intraventricular extension. (2) These aneurysms are frequently very small (<5 mm). Therefore, they cannot be detected on initial angiograms in some cases. (3) These small aneurysms cannot be usually clipped without sacrificing the parent artery. (4) Sacrificing distal AChoA (beyond the plexal point) does not usually cause any neurological deficit, but, whenever possible, this artery should be preserved.     

Distal aneurysm of posterior inferior cerebellar artery: report of two cases--pitfall in diagnosis

Two cases treating aneurysms of the distal PICA were reported, and 36 cases with 39 aneurysms in the literatures in Japan were reviewed concerning the distribution of aneurysms and their findings on CT. Case 1; a 68-year-old female suffered from sudden onset of severe headache and nausea. On admission, it was found she was lethargic. However, her consciousness deteriorated down to semicoma with tetraparetic condition soon after. CT revealed subarachnoid hemorrhage in the basal, quadrigeminal and supravermian cisterns and blood clots in the entire ventricle. Cerebral angiography demonstrated an aneurysm located at the distal segment of the left PICA. She was initially treated conservatively because of being in Hunt and Kosnik Grade 5, and then, 3 weeks after onset, suboccipital craniectomy was performed and the aneurysm was clipped successfully. Case 2; a 60-year-old, female, suddenly experienced severe suboccipitalgia and vomiting. CT revealed subarachnoid hemorrhage in the entire subarachnoid space and intraventricular hemorrhages in the 4th, 3rd and lateral ventricles. Subsequently cerebral angiography was performed and left VAG demonstrated an aneurysm at the left A2-A3 junction. She underwent bifrontal craniotomy and the aneurysm was clipped via the interhemispheric approach. Her postoperative course was uneventful. Postoperative left CAG showed successful clipping of the aneurysm. However, left VAG suggested an aneurysm-like shadow in the right PICA. Right BAG carried out one week later demonstrated an aneurysm at the distal segment of the right PICA. This aneurysm was then clipped successfully under suboccipital craniectomy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Isolated intraventricular hemorrhage due to a ruptured vertebral artery aneurysm

A rare case of ruptured aneurysm originating from the vertebral artery, and presenting an isolated clot in the fourth ventricle is reported. The patient underwent surgery via a right lateral suboccipital craniectomy on the third day. As the aneurysm was huge and partially thrombosed, trapping was performed and completed successfully. If isolated intraventricular hematoma was found without obvious parenchymal hemorrhage or subarachnoid clot, the diagnosis of vertebral artery aneurysm should be considered as a possibility in addition to posterior inferior cerebellar artery aneurysm. Complete vertebral angiography is indispensable for the recognition of this condition.     

Pathology of intracerebral hemorrhage in ruptured aneurysms of the posterior communicating artery at its origin from the internal carotid artery

There were thirty-two autopsied cases of ruptured aneurysms at the junction of the internal carotid and posterior communicating arteries in the file of Montefiore Medical Center from 1948 to 1983 (Table 1). The age range of the patients was 11-83 years. Seven were men and twenty-five were women. Fifteen had previous surgery; either clipping of the neck of the aneurysm or ligation of the common carotid artery. Analysis of the hemorrhage associated with the ruptured aneurysms revealed two distinct patterns. One is subarachnoid hemorrhage alone (18 cases) and another is subarachnoid hemorrhage and intraventricular rupture through the temporal horn (14 cases). These aneurysms did not produce a large intracerebral hematoma in the temporal lobe because they ruptured into the temporal horn. Among the post-operative cases (14 cases), only 3 cases had intraventricular hemorrhage. Correlation of these autopsy findings with CT Scans revealed that an intraventricular hematoma in the temporal horn could be interpreted as a large intracerebral hematoma in the temporal lobe.     

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.