Posteroinferior Cerebellar Artery Research Articles

Síndrome de Wallemberg secundario a disección de la arteria vertebral por manipulación quiropráctica

Chiropractic manipulations of the cervical region are techniques that are used more and more frequently to treat a number of osteomuscular pathologies, but can give rise to important complications, such as the dissection of the cervical arteries. Dissection of the vertebral artery generally presents as alternating syndromes, of which Wallenberg s syndrome, either complete or incomplete, is the most frequent. In this paper we review the literature published to date on the pathogenesis, risk factors, clinical features, chronopathology, diagnosis, treatment and prognosis of this complication. We describe the case of a young patient who suffered from incomplete Wallenberg s syndrome a few hours after a single session of cervical chiropractic manipulation, and we also show the resonance images that were used to support the diagnosis. The appearance of a pain in the neck and neurological symptoms in a patient who has undergone chiropractic manipulation in the last few hours or days must lead us to consider a possible dissection of the cervical arteries. Dissection of the vertebral artery usually gives rise to alternating syndromes, the most frequent of which is lateral bulbomedullary infarction or Wallenberg s syndrome due to proximal occlusion of the posteroinferior cerebellar artery. Magnetic resonance angiography of the supra aortic trunks and cranial magnetic resonance scanning are valid techniques for demonstrating the dissection of the artery and the associated ischemic lesion.

Stroke after chiropractic manipulation as a result of extracranial postero-inferior cerebellar artery dissection

Objective: To describe a case of dissection of the postero-inferior cerebellar artery (PICA) after cervical manipulation. Clinical Features: After cervical manipulation, a 42-year-old woman had a cerebellar syndrome related to an infarct in the area supplied by the PICA, confirmed by computed tomography of the brain. Cerebral angiography showed a normal appearance of the vertebral artery, a cervical extradural origin of PICA, and a dissection of the latter at the C1-C2 level. Intervention and Outcome: Anticoagulant treatment with heparin was implemented. A positive outcome was achieved after 3 weeks. Conclusion: Anatomical variations of the vertebral arteries and their branches are not infrequent and may constitute a predisposing factor to complications after neck manipulation. (J Manipulative Physiol Ther 2002;25:588-90)

Clinical and radiographic outcome in the management of posterior circulation aneurysms by use of direct surgical or endovascular techniques.

Posterior circulation aneurysms can be difficult lesions to treat surgically, and they have potential for high morbidity and mortality, particularly in elderly patients or those in poor neurological condition. In an effort to improve outcomes, our combined neurosurgical and neuroendovascular unit has used both surgical clipping and endovascular coiling techniques to treat posterior circulation aneurysms. Patients considered at high risk for surgery were managed with endovascular treatment. From 1990 to 1998, 197 posterior circulation aneurysms in 189 patients were treated in our combined neurovascular unit. Of these aneurysms, 128 were ruptured, 63 were unruptured, and 6 had a distant history of rupture in patients who came to our center for delayed or repeat treatment. A total of 132 aneurysms were treated with surgical clipping (85 ruptured, 46 unruptured, and 1 with distant history of rupture) and 65 aneurysms were treated with endovascular coiling (43 ruptured, 17 unruptured, and 5 with distant history of rupture). Dissecting aneurysms of the vertebral or posteroinferior cerebellar arteries or aneurysms treated with proximal (Hunterian) occlusion were excluded from this analysis. Surgical risk was assessed using a previously described system (Massachusetts General Hospital [MGH] grade), which incorporates age, Hunt and Hess grade, size of lesion, and Fisher grade. Overall clinical outcomes at 1 year of follow-up were 77.2% excellent or good, 10.2% fair, 4.1% poor, and 8.6% dead. Surgical treatment resulted in 95.6% complete aneurysm occlusion and 4.4% with residual aneurysm after surgical treatment, whereas endovascular treatment resulted in 32.3% complete occlusion, 26.2% with residual aneurysm, and 41.5% with partial occlusion. In most cases, however, treatment with Guglielmi detachable coils (Boston Scientific/Target, Fremont, CA) was performed for palliation rather than complete radiographic occlusion. Outcome was closely associated with MGH grade with either treatment modality. Excellent/good outcomes were achieved in 96, 92.3, 82.9, 46.2, and 0% of surgically treated patients with MGH Grades of 0, 1, 2, 3, and 4, respectively. In comparison, excellent/good outcomes were achieved in 100, 84.2, 61.9, 0, and 50% of endovascularly treated patients with MGH Grades of 0, 1, 2, 3, and 4, respectively. A combined surgical and endovascular approach to posterior circulation aneurysms can achieve good outcomes in high-risk surgical patients treated by use of coiling techniques.

Unilateral Cerebellar Aplasia

We report the case of a 24-year-old woman showing an exceptional unilateral cerebellar absence in an otherwise normal Cenral Nervous System, accidentally discovered on CT and MRI. The patient underwent emergency CT scan after head injury and subsequently MRI. These examinations showed no cranio-encephalic traumatic lesion but revealed the absence of the right cerebellar hemisphere and inferior vermis both totally replaced by cerebrospinal fluid. Neither involvement of the brain stem nor associated supratentorial abnormality was seen. On MR angiographic sequences a mild hypoplasia of the right vertebral artery was seen; the superior cerebellar artery, anterior cerebellar artery and posteroinferior cerebellar artery were not identifiable on the right side. CT and MR findings along with anamnestic details and clinical picture suggest that the unusual cerebellar anomalies found in the present case might result from a destructive lesion, whose exact time and nature are unknown. We named this finding “aplasia” even if the most appropriate term may be “atrophia”. The presence both of a symmetrically normalsized posterior fossa and a normal-located tentorium suggests the previous development of a part of hindbrain, that was subsequently destroyed. This circumstance may even explain the absence of symptoms. In fact, a complete functional recovery may occur in response to destructive lesions resulting in atrophy, thanks to enhanced cerebellar plasticity. Selective hemispheric impairment can result from intrauterine or perinatal exposure to many agents, including hypoxic-ischemic conditions, or metabolic diseases expressed early in fetal life. However, no significant events emerged in our case. A vascular disease might also play a role because, more than the remnant factors, it could escape clinical detection. We review the classification of cerebellar abnormalities from an embryological standpoint, pointing out the role of atrophic conditions on the clinical picture.

Aneurysm of the Distal Posteroinferior Cerebellar Artery of Extracranial Origin: Case Report

We describe a very rare case involving a ruptured intracranial aneurysm at the distal posteroinferior cerebellar artery (PICA) branching from the extracranial vertebral artery. 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. 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. 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.

Subarachnoid Hemorrhage from Vertebral Artery Dissecting Aneurysms Involving the Origin of the Posteroinferior Cerebellar Artery: Report of Two Cases and Review of the Literature

Few reports have been published on ruptured vertebral artery dissecting aneurysms in which the posteroinferior cerebellar artery (PICA) arises from the aneurysm wall, and there is ongoing debate as to the proper management of this type of aneurysm. This article describes two patients. Both patients presented with subarachnoid hemorrhage and were admitted to our institution on the day of rupture. Computed tomography revealed that the subarachnoid hemorrhage was located mainly in the posterior fossa. Cerebral angiography demonstrated a vertebral dissecting aneurysm involving the origin of the PICA. In one patient, the PICA was very large. One patient was treated by trapping, with the PICA involved in the trapped segment. Postoperatively, the patient experienced transient mild hoarseness and dysphasia but recovered completely. The other patient, whose PICA was very large, was initially treated by endovascular proximal occlusion. This resulted in marked enlargement of the distal part of the aneurysm, indicating a need for surgical treatment. A clip was applied to the origin of the PICA after anastomosis of the occipital artery to the PICA. The patient recovered well and was discharged with no neurological deficits. The ideal method of treatment for patients with dissecting aneurysms of the vertebral artery involving the PICA origin is complete isolation of the aneurysm by trapping, with revascularization of the PICA. However, trapping alone is one possible treatment option. If proximal clipping alone is carried out, follow-up angiography is mandatory to observe any changes in the aneurysm.

Subarachnoid Hemorrhage from Vertebral Artery Dissecting Aneurysms Involving the Origin of the Posteroinferior Cerebellar Artery: Report of Two Cases and Review of the Literature

Subarachnoid Hemorrhage from Vertebral Artery Dissecting Aneurysms Involving the Origin of the Posteroinferior Cerebellar Artery: Report of Two Cases and Review of the Literature

Spontaneous Resolution of a Ruptured Dissecting PICA Aneurysm

Spontaneous dissecting aneurysms (SDAs) seldom involve the intradural vertebral artery VA, the posterior cerebral, basilar or postero inferior cerebellar arteries (PICAs), where they produce subarachnoid haemorrhage and/or ischaemia. These lesions may develop spontaneously or occasionally after minor trauma and occur in young people in whom there is no underlying abnormality to explain the appearance of the dissection in most cases. Spontaneous dissecting aneurysm of the PICA is rare and its natural history is not well understood. Surgery or endovascular treatment for PICA dissection remain controversial because they suggest vessel occlusion. Only in a few cases is the bypass between the occipital artery and the PICA possible with trapping of the dissected segment. Reinforcement of the arterial wall does not seem efficient and the surgical approach per se with sole exclusion of the aneurysm may be disastrous. We describe two cases of SDA of PICA that presented with subarachnoid haemorrhage (SAH), treated conservatively, with spontaneous cure of the lesions, angiographically confirmed at mid-time follow-up of five and four months. These favourable spontaneous thromboses, like 11 other similar case reported in the literature, did not show any rebleed. The possibility of a benign clinical course of this lesion exists; clinical and angiographic management of the patient before a decision for a aggressive treatment is proposed.

Comments

OBJECTIVE: Posteroinferior cerebellar artery aneurysms have an incidence of approximately 0.49%. Reports in the literature are sparse concerning outcomes in this patient population. We report our results for 38 consecutive patients who were treated during the last 6.5 years. METHODS: All patients (n = 38) with posteroinferior cerebellar artery aneurysms that were surgically treated at Zale-Lipshy University Hospital between January 1990 and May 1997 were retrospectively reviewed. Data were collected and analyzed relating to demographics, condition at presentation, lesion characteristics, associated medical problems, postsurgical complications, and outcome. RESULTS: Sixty-six percent of the patients (n = 25) experienced neurological sequelae, which included symptomatic vasospasm, hydrocephalus, dysarthria, paresis, diplopia, ataxia, and facial paralysis. Many, however, showed significant improvement during their hospitalization and during the course of the ensuing year. Seventy-four percent of the patients had a Glasgow Outcome Scale score of 1 or 2 at the time of discharge, 91% at 6 months after surgery, and 89% at 1 year after surgery. CONCLUSION: This review summarizes the presentations and outcomes of 38 consecutive surgical cases during a 6.5-year period and concludes that posteroinferior cerebellar artery aneurysms are not benign entities. The study does, however, also demonstrate that patients have significant recuperative potential after the treatment of these lesions.

Posteroinferior cerebellar artery aneurysms: surgical results for 38 patients.

Posteroinferior cerebellar artery aneurysms have an incidence of approximately 0.49%. Reports in the literature are sparse concerning outcomes in this patient population. We report our results for 38 consecutive patients who were treated during the last 6.5 years. All patients (n = 38) with posteroinferior cerebellar artery aneurysms that were surgically treated at Zale-Lipshy University Hospital between January 1990 and May 1997 were retrospectively reviewed. Data were collected and analyzed relating to demographics, condition at presentation, lesion characteristics, associated medical problems, postsurgical complications, and outcome. Sixty-six percent of the patients (n = 25) experienced neurological sequelae, which included symptomatic vasospasm, hydrocephalus, dysarthria, paresis, diplopia, ataxia, and facial paralysis. Many, however, showed significant improvement during their hospitalization and during the course of the ensuing year. Seventy-four percent of the patients had a Glasgow Outcome Scale score of 1 or 2 at the time of discharge, 91% at 6 months after surgery, and 89% at 1 year after surgery. This review summarizes the presentations and outcomes of 38 consecutive surgical cases during a 6.5-year period and concludes that posteroinferior cerebellar artery aneurysms are not benign entities. The study does, however, also demonstrate that patients have significant recuperative potential after the treatment of these lesions.

Extradural origin of the posteroinferior cerebellar artery: an anatomic study with histological and radiographic correlation.

The posteroinferior cerebellar artery (PICA) usually arises from the intradural segment of the vertebral artery (VA). The extradural origin of the PICA is infrequent. Its preoperatory identification is important in surgical strategy during the exposure of the VA. During an anatomic prosection, the VA was exposed at the craniocervical junction in cadaveric adult specimens. The extradural origin of the PICA was encountered bilaterally in one specimen and on one side in a second specimen. An anatomic study with histological and radiographic correlation was performed. Perforating branches originate from the PICA. They supply the middle and inferior third of the olive and the lateral aspect of the medulla. The PICA has cortical branches that lead to the cerebellum. Injury to the PICA can produce an infarction of these neural structures that can be asymptomatic or cause major neurological deficits. Radiographic results obtained using a lateral projection provided the most reliable delineation of the extradural origin of the PICA. When this artery originates at, or posterior to, the posterior aspect of the occipital condyle, an extradural origin is likely. Bilateral selective vertebral angiography should be performed with special attention to the relationships of PICA origins before any surgical exposure of the VA at the craniocervical junction, unless magnetic resonance angiography provides this information without question. A thorough understanding of the relative dominance of the VAs and PICAs, the location of the PICA origin, and the collateral circulation of the posterior fossa are prerequisites to surgery in this region. The preoperative identification of an extradural PICA is important in planning surgical strategy and in avoiding complications during operations near the foramen magnum.

Extradural Origin of the Posteroinferior Cerebellar Artery: An Anatomic Study with Histological and Radiographic Correlation

Extradural Origin of the Posteroinferior Cerebellar Artery: An Anatomic Study with Histological and Radiographic Correlation

Extradural Origin of the Posteroinferior Cerebellar Artery: An Anatomic Study with Histological and Radiographic Correlation

Extradural Origin of the Posteroinferior Cerebellar Artery: An Anatomic Study with Histological and Radiographic Correlation

Extradural Origin of the Posteroinferior Cerebellar Artery: An Anatomic Study with Histological and Radiographic Correlation

Extradural Origin of the Posteroinferior Cerebellar Artery: An Anatomic Study with Histological and Radiographic Correlation

Bilateral (Mirror-image) Aneurysms at the Origin of the Posteroinferior Cerebellar Artery: Case Report

Bilateral (Mirror-image) Aneurysms at the Origin of the Posteroinferior Cerebellar Artery: Case Report

Bilateral (Mirror-image) Aneurysms at the Origin of the Posteroinferior Cerebellar Artery: Case Report

Bilateral (Mirror-image) Aneurysms at the Origin of the Posteroinferior Cerebellar Artery: Case Report

Bilateral (Mirror-image) Aneurysms at the Origin of the Posteroinferior Cerebellar Artery: Case Report

Bilateral (Mirror-image) Aneurysms at the Origin of the Posteroinferior Cerebellar Artery: Case Report

Causes and mechanisms of cerebellar infarction in young patients.

The incidence of cerebellar infarction in a series of patients with stroke is approximately 1.5%. The average patient age in most reported series is 62 years. The most common etiologies in this age group are atherosclerosis and cardiac embolism. The aim of this study was to determine the causes and mechanisms of cerebellar infarction in patients younger than 40 years. We analyzed retrospectively the clinical and radiological data from 21 men and 16 women with cerebellar infarction admitted to our hospital from January 1986 to December 1996. The patients had been studied extensively to determine the etiology of the cerebellar infarction. In the 37 patients (mean age, 30 years), 29 infarcts were limited to one territory (15 in the posteroinferior cerebellar artery [PICA]; 14 in the superior cerebellar artery); 8 had nonterritorial infarctions. The most common stroke mechanisms in each territory were as follows: PICA: nonatherosclerotic vasculopathic (67%), cardioembolic (20%), and hematologic and cryptogenic (each 7%); superior cerebellar artery: cardioembolic (42%), cryptogenic (31%), migrainous (21%), and nonatherosclerotic vasculopathic and hematologic (each 7%); and mixed territory: nonatherosclerotic vasculopathic (50%), cryptogenic (25%), cardioembolic (12%), and hematologic (12%). The most common mechanism of cerebellar infarctions was arterial occlusion as a result of intracranial vertebral artery dissection (40%), mainly with PICA involvement. Embolism from a cardiac source resulted primarily from patent foramen ovale and rheumatic valvular disease. Hematologic disturbances and migraine were responsible for a few cases.

Ruptured vertebrobasilar aneurysms: frequency of the nonaneurysmal perimesencephalic pattern of hemorrhage on CT scans.

To determine the frequency of the computed tomographic (CT) pattern of nonaneurysmal perimesencephalic subarachnoid hemorrhage in the setting of ruptured posterior fossa aneurysms. Four neuroradiologists independently and retrospectively reviewed cranial CT scans of 169 patients with ruptured vertebrobasilar aneurysms (44 cases of posteroinferior cerebellar artery aneurysm, 20 cases of superior cerebellar artery aneurysm, and 105 cases of basilar-tip aneurysm). The mean frequency of nonaneurysmal perimesencephalic pattern of subarachnoid hemorrhage in ruptured vertebrobasilar aneurysms was 7.1% (48 of 676 readings) among the four readers. The mean frequency of aneurysms with the pattern of hemorrhage for each location was as follows: basilar tip, 9.8% (41 of 420 readings); superior cerebellar artery, 5.0% (four of 80 readings); and posteroinferior cerebellar artery, 0%. In 75% (six of eight) of the cases in which the CT pattern of hemorrhage was deemed compatible by all readers with nonaneurysmal hemorrhage, the clinical presentation was mild. Because ruptured posterior fossa aneurysms manifest with the nonaneurysmal pattern of hemorrhage in approximately 10% of cases, a high degree of suspicion should be maintained even if the pattern of subarachnoid hemorrhage suggests a nonaneurysmal origin and clinical symptoms are mild.

Vertebral artery dissection from neck flexion during paroxysmal coughing

Vertebral artery dissection has a characteristic presentation that should be considered when symptoms are preceded by any trauma that causes neck movement. We present the case of a man with vertebral artery dissection following severe coughing that presented as a postero-inferior cerebellar artery territory stroke. The patient was anti-coagulated, and his neurologic deficits were partially resolved. The mechanism and presentation of vertebral artery dissection are discussed with an emphasis on early detection.