Origin Of Posterior Inferior Cerebellar Artery Research Articles

Wallenberg’s syndrome with extradural–extracranial origin of the posterior inferior cerebellar artery

We report a case of lateral medullary syndrome (LMS) with extradural origin of the posterior inferior cerebellar artery (PICA). A 45-year-old construction worker presented with acute signs and symptoms of typical LMS. Prolonged work-related neck extension was reported just prior to the onset of symptoms. Cerebral angiography revealed a patent vertebrobasilar tree with an extradural origin of an otherwise normal appearing PICA ipsilaterally. Workup did not show evidence for cardioembolic or atheroembolic source. The presence of an extradural origin of PICA may be considered a predisposing factor for non-traumatic LMS associated with head and neck movement.

Endovascular Treatment of Atypical Posterior Circulation Aneurysms: Technical Results and Review of the Literature

we report our technical success and complication rates in treating posterior circulation aneurysms at sites other than the basilar apex, superior cerebellar artery origin, or the posterior inferior cerebellar artery origin via endovascular embolization or sacrifice. we retrospectively reviewed case records for patients undergoing coil embolization of atypical posterior circulation aneurysms from January 2003 to December 2007. thirty-two aneurysms in 32 patients were treated. Twenty-one patients (65%) presented with a subarachnoid hemorrhage. Twenty-two aneurysms were treated with coiling alone, 9 with stent-assisted coiling, and 1 with a combination of Onyx plus stent-assisted coiling. Twelve aneurysms were treated with vessel sacrifice. Immediately post procedure, 27/32 aneurysms (84%) were considered successfully treated, resulting in either vessel sacrifice, complete obliteration, or minimal neck remnant. Sixteen of 19 patients (84%) were considered successfully treated at a mean angiographic follow up of 8 months. The procedural morbidity and mortality was 15% and 6% respectively. endovascular embolization remains a viable and durable method of treatment for atypical posterior circulation aneurysms.

PICA Origin Aneurysm Diagnosed 27 Years after Microvascular Decompression of Cranial Nerve VII

The authors report a case of a posterior inferior cerebellar artery origin aneurysm causing brainstem compression and swallowing difficulty. The patient had an ipsilateral microvascular decompression of cranial nerve VII for hemifacial spasm 27 years prior to the discovery of the aneurysm. The aneurysm was successfully treated endovascularly. A discussion of possible etiologies of the aneurysm's formation is presented.

Anatomical triangles defining surgical routes to posterior inferior cerebellar artery aneurysms

Surgical routes to posterior inferior cerebellar artery (PICA) aneurysms are opened between the vagus (cranial nerve [CN] X), accessory (CN XI), and hypoglossal (CN XII) nerves for safe clipping, but these routes have not been systematically defined. The authors describe 3 anatomical triangles and their relationships with PICA aneurysms, routes for surgical clipping, outcomes, and angiographically demonstrated anatomy. The vagoaccesory triangle is defined by CN X superiorly, CN XI laterally, and the medulla medially. It is divided by CN XII into the suprahypoglossal triangle (above CN XII) and the infrahypoglossal triangle (below CN XII). From a consecutive surgical series of 71 PICA aneurysms in 70 patients, 51 aneurysms were analyzed using intraoperative photographs. Forty-three PICA aneurysms were located inside the vagoaccessory triangle and 8 were outside. Of the aneurysms inside the vagoaccessory triangle, 22 (51%) were exposed through the suprahypoglossal triangle and 19 (44%) through the infrahypoglossal triangle; 2 were between triangles. The lesions were evenly distributed between the anterior medullary (16 aneurysms), lateral medullary (19 aneurysms), and tonsillomedullary zones (16 aneurysms). Neurological and CN morbidity linked to aneurysms in the suprahypoglossal triangle was similar to that associated with aneurysms in the infrahypoglossal triangle, but no morbidity was associated with PICA aneurysms outside the vagoaccessory triangle. A distal PICA origin on angiography localized the aneurysm to the suprahypoglossal triangle in 71% of patients, and distal PICA aneurysms were localized to the infrahypoglossal triangle or outside the vagoaccessory triangle in 78% of patients. The anatomical triangles and zones clarify the borders of operative corridors to PICA aneurysms and define the depth of dissection through the CNs. Deep dissection to aneurysms in the anterior medullary zone traverses CNs X, XI, and XII, whereas shallow dissection to aneurysms in the lateral medullary zone traverses CNs X and XI. Posterior inferior cerebellar artery aneurysms outside the vagoaccessory triangle are frequently distal and superficial to the lower CNs, and associated surgical morbidity is minimal. Angiography may preoperatively localize a PICA aneurysm's triangular anatomy based on the distal PICA origin or distal aneurysm location.

JUGULAR TUBERCLE AND VERTEBRAL ARTERY/POSTERIOR INFERIOR CEREBELLAR ARTERY ANATOMIC RELATIONSHIP

To evaluate structural variations of the jugular tubercles (JTs) and their relationships with the vertebral artery, the posterior inferior cerebellar artery (PICA), and the vertebrobasilar junction (VBJ). The depth, height, and width of the JTs were measured using 30 cadaveric basicranial specimens and 50 three-dimensional angiography computed tomographic (angio-CT) scans evaluating morphological variations between the 2 sides. Angio-CT analysis evaluated the relationships of the JTs with the vertebral arteries and the PICAs. The location of the VBJ with respect to the JT level in the coronal plane was evaluated. In the cadaveric specimens, the mean JT depth ranged from 0.9 to 3.1 cm, the mean height ranged from 0.6 to 1.5 cm, and the mean width ranged from 0.4 to 1.2 cm. According to the 3-dimensional angio-CT scans, JT measurements ranged as follows: depth, 0.7 to 2.6 cm; height, 0.6 to 1.4 cm; and width, 0.3 to 1.2 cm. The vertebral artery was in close contact with the JT on the left side in 30% of cases and on the right side in 24% of the cases. On axial scans, the PICA origin was classified as anterior to the JT in 20.5% of patients on the left side and 17.4% on the right, at the JT level in 50% of patients on the left side and 45.7% on the right, and posterior to the JT in 29.5% of patients on the left side and 36.9% on the right. On coronal scans, the PICA origin was classified as superior to the JT in 13.6% of patients on the left side and 8.7% on the right, at the JT level in 54.6% of patients on the left side and 50% on the right, and inferior to the JT in 31.8% of patients on the left side and 41.3% on the right. In the coronal plane, the VBJ was located above the tubercles in 16 patients (32%), at the JT level in 28 patients (56%), and below the tubercles in 6 patients (12%). A precise morphometric analysis of the JTs on 3-dimensional CT scans was quick and safe and showed significant variations in their size and shape. The relationship of the JT with vertebral artery and the PICA varied significantly, as well as with the VBJ location. Knowledge of these morphological variations can contribute to optimal preoperative surgical planning, minimizing retraction and reducing morbidity during extreme lateral infrajugular-transtubercular exposure surgery.

Detachable Coil Embolization for Saccular Posterior Inferior Cerebellar Artery Aneurysms

Surgical treatment of posterior inferior cerebellar artery (PICA) aneurysms is challenging due to limited surgical accessibility. Endovascular approach has a benefit of avoiding direct injury to the brainstem or lower cranial nerves. Therefore, it has recently been considered an alternative or primary modality for PICA aneurysms. We retrospectively assessed outcomes following detachable coil embolization of saccular PICA aneurysms. From February 1997 to December 2007, we performed endovascular procedures to treat 15 patients with 15 PICA aneurysms. Fourteen patients with 14 PICA aneurysms morphology of which was saccular were reviewed retrospectively. Twelve patients had ruptured aneurysms. The aneurysms arose from the PICA origin site (n = 12), the PICA lateral medullary segment (n = 1), or the PICA tonsilomedullary segment (n = 1). Complete aneurysm occlusion was achieved in 10 patients, residual neck in 3, and residual sac in one. Radiological follow-up was performed in 7 patients with mean duration of 34.7 months (range, 1-97 months) and showed stable or complete occlusion in 6 patients. There were no rebleeding or retreatment after endovascular treatment. Thromboembolism was the only procedure-related complication (n = 4 ; 28.6%). Asymptomatic PICA infarction occurred in two patients and symptomatic PICA infarction in two elderly patients with poor clinical grade. Of these procedural PICA infarction cases, 1 symptomatic PICA infarction patient developed ventriculitis and septic shock leading to death. The clinical outcome was good in 10 patients (71.4%). In the present study, detachable coil embolization has shown as an efficient modality for PICA saccular aneurysms challenging indications of microsurgery. However, thromboembolic complications should be considered, especially in poor clinical elderly patients with ruptured aneurysms.

Stent Placement for the Treatment of Intracranial Vertebral Artery Dissecting Aneurysms

Intracranial vertebral artery (VA) dissecting aneurysms are commonly treated with endovascular parent artery occlusion. However, this procedure cannot be applied to patients with aplastic/hypoplastic contralateral VA or with posterior inferior cerebellar artery (PICA) involved in the dissecting segment. Recently, endovascular treatment using stents for VA dissecting aneurysms has been reported. In this study, we investigated the safety, efficacy, and optimal application of this treatment. Thirteen patients were treated using stents to preserve the patency of the VA, PICA, and anterior spinal artery (ASA). In 6 patients, PICA or ASA was involved in the dissecting segment. Seven patients presented with subarachnoid hemorrhage (SAH), 4 with ischemic symptoms, 1 with headache without SAH, and 1 with incidental discovery. Eleven patients were treated with stent-assisted coil embolization and 2 with stenting only. Stents were successfully deployed in all patients. Of the 11 patients treated with stent-assisted coiling, complete obliteration of the aneurysm was achieved in 5 patients and residual dome filling was present in 5. In the remaining patient, aneurysm rupture occurred during the insertion of the coils, and therefore parent artery occlusion was performed. In 2 patients treated with stenting only, complete obliteration was confirmed by follow-up angiography. Growth of the aneurysmal dilatation occurred in 1 patient, but subsequent SAH was not observed in any patient. Endovascular treatment using stents and coils appears safe and effective, and provides an effective alternative to treating patients with aplasia/hypoplasia of the contralateral VA and some patients with involvement of the origin of PICA or ASA in the dissecting segment.

ＰＩＣＡ‐ｉｎｖｏｌｖｅｄ ｔｙｐｅの破裂椎骨解離性動脈瘤に対する急性期治療―ＰＩＣＡ灌流領域からの検討―

Urgent treatment of ruptured vertebral artery dissecting aneurysm (VADA) is imperative because of the high incidence of rebleeding and high mortality of recurrent bleeding. Especially, ruptured posterior inferior cerebellar artery (PICA)-involved VADA requires both prevention of rebleeding and revascularization of the PICA. Since 2001, we have treated 8 patients with ruptured PICA-involved type VADA during the acute stage, within 3 days after the hemorrhage. The treatment strategy included endovascular proximal occlusion followed by occipital artery-PICA bypass and PICA origin clipping (3 cases), proximal occlusion followed by internal trapping of the aneurysm after successful balloon test occlusion (1 case), only proximal occlusion (1 case), coil embolization of the aneurysmal dilatation followed by OA-PICA bypass and PICA origin clipping (1 case), internal trapping of the aneurysm (1 case), OA-PICA bypass, proximal clipping and proximal clipping (1 case). Aneurysmal shape change after acute treatment was observed in 5 cases. In 1 case to which the aneurysm decreased in size, PICA supplied only vermis branches. In 2 cases in which the size of the aneurysm did not change, PICA supplied vermis, tonsilar and hemispheric branches in 2. In 2 cases in which the size of the aneurysm increased, PICA supplied vermis, tonsilar and hemispheric branches in 1 and PICA supplied vermis, tonsilar, hemispheric and meningeal branches in 1. Because the possibility is high that the aneurysm will remain cases in which PICA supplied vermis, tonsilar and hemispheric branches, it is necessary to plan additional treatment with PICA revascularization.

Contralateral far-lateral approach for clipping of a ruptured vertebral artery–posterior inferior cerebellar artery aneurysm

Numerous nuanced approaches have been used to access posterior inferior cerebellar artery (PICA) aneurysms for microsurgical clipping. The authors report the case of a patient with a right vertebral artery (VA)-PICA aneurysm that was reached via a contralateral far-lateral approach. The wide-necked saccular/fusiform aneurysm arose from the lateral aspect of the right V(4) segment just proximal to the PICA origin, anterior to the jugular tubercle at the level of the hypoglossal canal. Computed tomography angiograms demonstrated the size and configuration of the aneurysm, and 3D reconstructions revealed the tortuosity of the right VA, defining its location just left of the midline adjacent to the lower clivus. A contralateral far-lateral approach to VA-PICA aneurysms should be considered when aneurysms cross the midline. Computed tomography angiography with volume rendering and interactive software capabilities can help identify the relationship of such an aneurysm to an individual's particular skull base osseous anatomy and is paramount in selecting the optimal microsurgical approach.

Posterior Inferior Cerebellar Artery Aneurysms: Incidence, Clinical Presentation, and Outcome of Endovascular Treatment

Results of endovascular treatment of PICA aneurysms are not well established. The purpose of this study was to report incidence, clinical presentation, and outcome of endovascular treatment in 46 patients with 47 posterior inferior cerebellar artery (PICA) aneurysms. Of 2169 aneurysms treated between January 1995 and March 2007, 60 were located on the PICA (incidence, 2.8%). Forty-seven proximal PICA aneurysms in 46 patients were treated with endovascular techniques, 37 ruptured (79%) and 10 unruptured (21%). Four patients presented with lower cranial nerve palsies. Mean aneurysm size was 6.8 mm (median, 6 mm; range, 2-32 mm). Forty-three aneurysms were occluded with coils (6 including the PICA origin), and 4 were treated with proximal vertebral artery (VA) occlusion. Four aneurysms treated with proximal VA occlusion were not occluded. Procedural rupture occurred in 9 aneurysms leading to death in 2 patients and to permanent disability in 1 patient. One patient developed lateral medullary and cerebellar infarctions after PICA occlusion. Combined mortality and morbidity was 8.6% (4 of 46). Outcome at 6 months in 38 surviving patients was good in 35 and moderate in 3. No hemorrhage occurred during 109 patient-years of follow-up. Symptoms of mass effect resolved in all 4 patients. In our experience, PICA aneurysms were challenging lesions, prone to procedural rupture. In some instances, endovascular treatment required occlusion of the parent PICA; usually this was well tolerated. In other instances, treatment required occlusion of the VA. Although this was effective in alleviation of symptoms of mass effect, it was not effective in causing thrombosis of the aneurysm.

Aneurisma disecante de la arteria cerebelosa posteroinferior

Dissecting aneurysms affecting exclusively to the posterior inferior cerebellar artery (PICA) are rare entities. Depending on the dissecting plane of the arterial wall, the clinical manifestations are subarachnoid hemorrhage (SAH) due to rupture or ischemia caused by stenosis or occlusion. Angiographic findings are fusiform dilatation with a narrowing of various degrees proximal to and distal to the fusiform lesion. Magnetic resonance imaging (MRI) can be useful demonstrating the intramural hematoma. We report a 47-year-old man who suffered from SAH. He was neurologicaly intact and vertebral angiography demonstrated and fusiform aneurysm at the origin of the left PICA. He was operated by trapping of the dissecting segment. The patient's postoperative course was uneventful despite of severe vasospasm showed in follow up angiography. Aggressive treatment has been recommended for dissecting aneurysms of the PICA and specially for those presenting with SAH. Both the surgical and endovascular procedures are effective and with good results.

Treatment of vertebral artery aneurysms with transposition of the posterior inferior cerebellar artery to the vertebral artery combined with parent artery occlusion

The authors describe transposition of the posterior inferior cerebellar artery (PICA) to the vertebral artery (VA) combined with parent artery occlusion for the treatment of VA aneurysms in cases in which a clip could not be applied because of the origin of the ipsilateral PICA. The aneurysm is trapped through a lower lateral suboccipital craniectomy. The PICA is then cut just distal to the aneurysm, and the PICA and VA proximal to the aneurysm are anastomosed in an end-to-end or end-to-side fashion. The surgical procedure was successfully performed in two patients, each of whom had hypoplastic occipital arteries (OAs). The PICA contralateral to the lesion was hypoplastic in one patient and distant to the ipsilateral PICA in the other patient. Mild transient dysphagia developed postoperatively in one patient due to glossopharyngeal and vagus nerve palsy, and the other patient had an uneventful postoperative course. In both patients, postoperative cerebral angiography demonstrated good patency of the transposed PICA. These results show that transposition of the PICA to the VA is a useful procedure for the reconstruction of the PICA when parent artery occlusion is necessary to exclude a VA aneurysm involving the origin of the PICA and when OA-PICA anastomosis or PICA-PICA anastomosis cannot be performed.

Prediction of rebleeding from angiographic features in vertebral artery dissecting aneurysms

To identify patient characteristics and angiographic features that predict high risk for rebleeding in vertebral artery (VA) dissecting aneurysms. We analyzed 62 patients treated for subarachnoid hemorrhage (SAH) from VA dissecting aneurysms (male: female, 46:16; mean age, 51.7 +/- 8 years). Univariate and multivariate stepwise logistic regression analyses were performed to assess relationships between rebleeding rate and age, gender, history of hypertension, sidedness of the aneurysm, angiographic configuration, and location relative to the origin of the posterior inferior cerebellar artery (PICA). Rebleeding occurred in 22 patients (37%), mostly within 24 h. Patients without rebleeding had favorable outcomes, while patients with rebleeding showed higher mortality. Angiographic patterns with high rebleeding rates included "stenosis and dilation" (50%), and "lateral protrusion" (43%), contrasting with "dilation and stenosis" (20%) and other types. Rebleeding also was likely in aneurysms proximal to or at the PICA origin (rate, 47% or 46%) than distal to the PICA origin (21%). Multivariate logistic regression analysis found two factors independently associated with rebleeding: angiographic pattern of the aneurysm (odds ratio 1.88:1, P=0.0366), and location relative to the PICA origin (odds ratio 4.93:1, P=0.028). High risk of rebleeding in VA dissecting aneurysms can be predicted by angiographic configurations such as "stenosis and dilation" and "lateral protrusion" and by location at or proximal to the PICA origin.

非出血性解離性脳動脈りゅうの治療方針 非出血性解離性脳動脈りゅうの血管内治療の適応とＰｉｆｔａｌｌ

We reviewed 55 unruptured dissecting aneurysms treated in Nagoya University and its affiliated hospitals over the last 7 years, and investigated the indications and pitfalls of such endovascular treatments. Among 55 aneurysms, 38 were endovascularly treated. The aneurysms were located on the vertebral artery (VA) in 47, the anterior cerebral artery in 3, middle cerebral artery in 1, and the posterior cerebral artery (PCA) in 4. As for the clinical presentation, ischemic symptoms was found in 22 cases, and headaches without neurological symptoms occurred in 27 patients. Five patients had bilateral lesions, including 3 aneurysms with 1 ruptured on the contralateral side. Thirty aneurysms were treated with endovascular trapping. A worsening of ischemic symptoms by trapping of VA was experienced in 5 cases in which the posterior inferior cerebellar artery (PICA) was hypoplastic or the aneurysm located far from the PICA origin. Two of 14 patients during the follow-up period showed complete thrombosis with parent artery occlusion, and 1 aneurysm underwent a spontaneous reduction in size. No aneurysms recurred or ruptured after endovascular trapping. According to our analysis, endovascular treatments proved very useful in avoiding the rupture of dissecting aneurysms. However, dissecting aneurysms of VA with hypoplastic PICA should be carefully performed. The aneurysms with the tendency for spontaneous regression should be followed up without surgical sacrifice of the parent artery. A targeted treatment strategy is needed against unruptured lesions following multiple dissections with SAH as well as parent artery stenosis at the dissection site.

Endovascular Treatment for Ruptured VA Dissecting Aneurysm Involving the Origin of PICA

Ruptured vertebral artery dissecting aneurysms (VADA) re-bleed frequently especially during first 24 hours, which makes the prognosis of the patients with this disease poor. Recently endovascular trapping with detachable platinum coils at an acute stage has been done for preventing re-bleeding. However, for the cases with dissecting aneurysm involving the origin of the posterior inferior cerebellar artery (PICA), these methods are hardly indicated because of the risk of ischemic complication in the PICA territory. We proposed a simple and effective therapeutic method for these cases. We occluded the affected vertebral artery (VA) near its root intending to introduce collateral blood flow from the deep cervical artery into the VA trunk. The controlled antegrade VA flow and retrograde flow from the contralateral VA make a watershed at the dissecting aneurysm, which promotes thrombosis of pseudolumen with preserving the antegrade blood flow of PICA.We treated two cases with ruptured VADA involving PICA, and in both cases thrombosis of aneurysm was obtained without any ischemic complication. This method would be considered as a treatment of choice to the cases with VADA involving PICA.

More Than a Pain in the Neck: Vertebral Artery Dissection and Subarachnoid Hemorrhage

Intracranial vertebral artery dissection is an uncommon but important cause of subarachnoid hemorrhage. These patients have a predilection for early rebleeding that makes early diagnosis and intervention imperative. The arterial dissection and associated dissecting aneurysm are often located close to the origin of the posterior-inferior cerebellar artery. Endovascular treatment techniques have been increasingly employed. An illustrative case that was treated successfully with coils but complicated by a posterior-inferior cerebellar artery territory infarction is presented. The objectives are to highlight the clinical features of this condition and to describe the problems associated with treatment, particularly those related to the posterior-inferior cerebellar artery origin.

Abstracts of literature

Abstracts of literature

Endovascular Management of Complete Vertebral Artery Dissection Presenting with Subarachnoid Haemorrhage

Spontaneous vertebral artery (VA) dissection may involve the intradural segment of the VA and result in subarachnoid haemorrhage (SAH). These lesions are frequently associated with recurrent SAH, and have a high mortality. Prior to the development of endovascular techniques the majority of these lesions were treated surgically. In cases where the dissection involved the posterior inferior cerebellar artery (PICA) origin surgery was associated with significant complications including recurrent SAH from retrograde VA flow into the dissected segment above the surgical clip. We describe two cases of complete VA dissection in which the entire intradural VA was sacrificed to prevent recurrent SAH. The first case tolerated planned left PICA occlusion without developing a significant neurological deficit. The second case had infarcted the right PICA territory at presentation.

Aneurysms of the posterior inferior cerebellar artery. A clinical and anatomical analysis.

The clinical and anatomical features of 21 surgically treated saccular aneurysms of the posterior inferior cerebellar artery (PICA) are analyzed. Seventeen of these lesions originated from the PICA-vertebral junction, and four arose from distal PICA branching sites. Twelve lesions arose from the left PICA, nine were right-sided, and all were small (less than 12.5 mm). Most of these aneurysms occurred in females (16 of 21) and presented as classic subarachnoid hemorrhage. The lack of specific focal deficits prevented an accurate pre-angiographic determination of aneurysm location in most instances. Clinically significant vasospasm and aneurysm multiplicity occurred with approximately equal frequency as at other locations. The angiographic and surgical features of these lesions are determined by the course of the vertebral artery and PICA; that is, they occur at branching sites and at curves in the parent vessel, and point in the direction in which flow would have continued if the curve at the aneurysm's origin had not been present. Aneurysms at the PICA-vertebral junction usualthese lesions are determined by the course of the vertebral artery and PICA; that is, they occur at branching sites and at curves in the parent vessel, and point in the direction in which flow would have continued if the curve at the aneurysm's origin had not been present. Aneurysms at the PICA-vertebral junction usualthese lesions are determined by the course of the vertebral artery and PICA; that is, they occur at branching sites and at curves in the parent vessel, and point in the direction in which flow would have continued if the curve at the aneurysm's origin had not been present. Aneurysms at the PICA-vertebral junction usually occur at least 1 cm above the foramen magnum level, arise distal to the PICA origin in the angle between the two vessels, and are best approached by a paramedian incision with the patient in the lateral recumbent position. Isolated clipping of the aneurysm neck is essential in this instance, as trapping may compromise vital perforating arteries of the brain stem. More distal (retromedullary) PICA aneurysms are sometimes associated with another vascular anomaly (two cases in this series), and are best handled through a bilateral suboccipital craniectomy. Clipping of the neck is the preferred treatment, but trapping is usually safe, if necessary.