Proximal Posterior Inferior Cerebellar Artery Research Articles

Treatment strategies of ruptured posterior inferior cerebellar artery aneurysm according to its segment

Background:The aim of this study was to evaluate the clinical outcomes between endovascular treatment (EVT) and surgery of the ruptured posterior inferior cerebellar artery (PICA) aneurysms and suggest proper management strategies according to the PICA segment.Methods:We retrospectively analyzed clinical and radiological data of patients with ruptured PICA aneurysms who underwent surgery or EVT from three different institutes. Clinical outcomes were evaluated by mRS.Results:We collected 39 consecutive patients with 39 ruptured PICA aneurysms; 26 patients were with proximal segment aneurysm and 13 patients were with distal. Of the 26 proximal PICA aneurysms, 20 aneurysms were treated with EVT and 6 aneurysms were treated with surgery. EVT seemed to have more favorable clinical outcome (mRS 0–2; mean mRS, 1.75 for EVT vs 3.50 for surgery, P = 0.152). Of the 13 distal PICA aneurysms, 7 aneurysms were treated with EVT and 6 were treated with surgery. Surgery showed more favorable clinical outcome (mean mRS, 2.63 for EVT vs 0.33 for surgery, P = 0.023) and lower procedure-related complication rate (42.9% for EVT vs 0% for surgery, P = 0.046) than EVT.Conclusions:For the treatment of ruptured PICA aneurysms, EVT seemed to have more favorable outcomes for proximal segment, while surgery showed more favorable outcomes for distal segment. Additional experience and follow-up are needed in a larger series to state the efficacy of this strategy.

Modified Far Lateral Approach for Posterior Circulation Aneurysms: An Institutional Experience

The modified far lateral approach is a modified version of the far lateral approach without drilling of the condyle. This approach can be used for accessing aneurysms anterior and anterolateral to the brainstem and craniovertebral junction. We describe the surgical outcome and complications of the modified far lateral approach for vertebrobasilar, proximal posterior inferior cerebellar artery, and vertebral artery aneurysms. The records of 26 patients with vertebrobasilar aneurysms who underwent surgery using the modified far lateral approach from 1994 to 2015 were retrospectively reviewed to analyze the clinical outcomes. Mean age of patients was 61 years (range, 38-84 years), and 18 patients were women. The most common presenting symptoms were sudden-onset headache (77%) and dizziness (35%). Of patients, 21 (81%) had saccular aneurysms, and 5 (19%) had fusiform aneurysms. The modified far lateral approach was used in 16 patients with posterior inferior cerebellar artery aneurysms, 6 patients with vertebral artery aneurysms, 2 patients with basilar aneurysms, 1 patient with a vertebrobasilar junction aneurysm, and 1 patient with an anterior inferior cerebellar artery aneurysm. All aneurysms were clipped successfully. Follow-up data were available for 25 patients (median duration 67 months). At last follow-up, 22 patients had a good recovery (modified Rankin Scale score 1-3), and 3 patients had a poor outcome (modified Rankin Scale score 4-6). Four patients developed lower cranial nerve palsy, and 7 patients developed new-onset hydrocephalus. The modified far-lateral approach without condyle resection and vertebral artery mobilization is associated with low procedure-related morbidity and comparable outcomes to the more extensive traditional approach.

Endovascular treatment of distal posterior inferior cerebellar artery aneurysms.

Objective:To assess the feasibility and results of endovascular treatment for ruptured distal posterior inferior cerebellar artery (PICA) aneurysms.Methods:We retrospectively reviewed our experience and results with endovascular treatments for a series of 13 consecutive patients with ruptured distal PICA aneurysms at the Southwest Hospital, Chongqing, China, treated between June 2011 and January 2015. Therapeutic considerations, intraoperative complications, and results were evaluated.Results:Endovascular embolization was performed in all 13 patients including selective coiling (4), stent-assisted coiling (2), microcatheter-assisted coiling (1), coiling without adjunctive techniques (1), and parent artery occlusion (5). Planed stent deployment failure occurred in one patients resulting from marked stenosis at the origin of the PICA; the patient’s existing partial Wallenberg’s syndrome became worse after treatment. Another 2 patients treated with parent artery occlusion recovered well without developing obvious neurological deficits, although a small cerebellar infarction of the distal PICA was observed. No patient experienced post procedural hemorrhage during the follow-up period (8-46 months; mean, 26.8 months).Conclusion:Distal PICA aneurysms can be managed effectively with various endovascular methods. Protective strategies using a stent or microcatheter for preserving the patency of the proximal PICA segment are a viable treatment option in reducing the potential risk of brain stem ischemia in selected patients.

Posterior inferior cerebellar artery reimplantation: buffer lengths, perforator anatomy, and technical limitations.

OBJECTIVE Reimplantation of the posterior inferior cerebellar artery (PICA) to the vertebral artery (VA) is a safe and effective bypass option after deliberate PICA sacrifice during the treatment of nonsaccular and dissecting aneurysms at this location. However, the anatomy and limitations of this technique have not been studied. The goal of this study was to define the surgical anatomy and buffer lengths specific to the proximal segment of the PICA related to 2 variations of PICA reimplantation: 1) reimplantation "along-VA" (simulating a dissecting VA aneurysm), and 2) reimplantation "across-VA" (simulating a nonclippable, proximal PICA aneurysm). METHODS Ten cadaver heads (20 sides) were prepared for surgical simulation. Twenty far-lateral approaches were performed. The PICA was mobilized and reimplanted onto the VA according to 2 different paradigms: 1) transposition along the axis of the VA (along-VA) to simulate a dissecting VA, and 2) transposition perpendicular to the axis of the VA (across-VA) to simulate a nonclippable, proximal PICA aneurysm. The buffer lengths provided by mobilization of the artery in each paradigm were measured and the anatomy of perforator branching on the proximal PICAs was analyzed. RESULTS The PICA was reimplanted in all surgical simulations. The most common perforating artery on the P1 and P2 segments was the short circumflex type. No direct perforator was found on the P1 segment. The mean buffer length with reimplantation along the VA axis was 13.43 ± 4.61 mm, and it was 6.97 ± 4.04 mm with reimplantation across the VA. The PICA was less maneuverable when it was reimplanted across the VA, due to perforator branches of the PICA (P3 segment). CONCLUSIONS The buffer lengths measured in this study describe the limitations of PICA reimplantation as a revascularization procedure for nonsaccular aneurysms in this location. PICA reimplantation is a revascularization option for dissecting VA aneurysms incorporating the PICA origin that are < 13 mm in length, and for nonsaccular proximal PICA aneurysms that are < 6 mm in diameter. The final decision to reimplant the PICA depends on careful inspection of perforator anatomy that is not visible preoperatively on angiography, as well as an assessment of technical difficulty intraoperatively.

Endovascular parent vessel sacrifice in ruptured dissecting vertebral and posterior inferior cerebellar artery aneurysms: clinical outcomes and review of the literature

BackgroundRuptured intracranial dissecting aneurysms must be secured quickly to prevent re-hemorrhage. Endovascular sacrifice of the diseased segment is a well-established treatment method, however postoperative outcomes of symptomatic stroke and re-hemorrhage...

Spontaneous Isolated Dissection of the Posterior Inferior Cerebellar Artery Presenting with Lateral Medullary Infarction

Background: Spontaneous isolated dissection of the posterior inferior cerebellar artery (PICA) is rare and presents with variable clinical course and prognosis. We report a case of spontaneous isolated PICA dissection presenting with lateral medullary infarction. Case Report: A 57-year-old female patient presented with right leg ataxia, headache, nausea and vomiting with a past medical history of hypertension. Neurological examination revealed right leg ataxia and left-side sensory change with right ptosis and miosis. The brain magnetic resonance imaging and magnetic resonance angiography showed an acute infarction in the right lateral medulla with abrupt luminal stenosis and subtle dilatation of the proximal segment of the right PICA. Transfemoral cerebral angiography showed an abrupt segmental stenosis of the right proximal PICA with a pre-stenotic fusiform dilatation, suggestive of dissection. The patient had a good clinical outcome with antiplatelet therapy. Conclusion: We report a rare case of spontaneous isolated PICA dissection with lateral medullary infarction. J Neurocrit Care 2014;7(2):137-140

Retrograde access to the posterior inferior cerebellar artery in balloon-assisted coiling of posterior inferior cerebellar artery aneurysms

IntroductionBalloon-assisted coil embolization of proximal posterior inferior cerebellar artery (PICA) aneurysms may be limited by the inferiorly oriented, acutely angulated origin of the PICA from the vertebral artery. The aim...

How I do it: occipital artery to posterior inferior cerebellar artery bypass

Aneurysms located at the proximal posterior inferior cerebellar artery (PICA) may need to be addressed by trapping and concomitant bypass. An anastomosis of the Occipital Artery (OA) to PICA is one bypass option in these cases. This bypass is highly challenging and its technical description is seldom cited in the literature. We describe the technical nuances of an OA-PICA end-to-side bypass in a 63-year-old man with a dissecting ruptured aneurysm of the third segment (tonsilomedullary) of the PICA. OA-PICA bypass option should remain as a treatment modality in the armamentarium of neurovascular surgeons.

Management of the proximal posterior inferior cerebellar artery aneurysms via far lateral approach with linear scalp incision

Objective To study the efficacyof surgical management of the proximal posterior inferior cerebellar artery(PICA) aneurysms by far lateral approach with linear scalp incision.Methods To manage the proximal PICA aneurysms by the far lateral approach and analyze its clinical outcome.According to Hunt-Hess Grade Score,of all 11 cases with the proximal PICA ruptured aneurysms,6 cases were of Ⅰ-Ⅱ grade,3 cases of Ⅲ and 2 cases of Ⅳ.Results All of 11 cases with the proximal PICA ruptured aneurysms were excluded for endovascular management because of their size,location and morphology,and then underwent craniotomy to clip or trap through OA-PICA bypass via far lateral approach with linear scalp incision.Postoperatively,therewasno mortality,3 cases had swallowing difficulty and improved by the time of discharge,2 cases underwent OA-PICA bypass after failure of direct clipping,the rest (8 cases) had no surgical complications.Condusions The proximal PICA aneurysms can be managed by directly clipping or bypass to trap the aneurysm via the far lateral approach with linear scalp incision,the bypass operation is the more suitable to the dissection aneurysm.All patients achieved good clinical outcome.The far lateral approach with the linear scalp incision can shorten the operation time and reduce surgical complication and gain enough surgical exposure. Key words: Aneurysm; Posterior inferior cerebellar artery; Far lateral approach

Endovascular treatment of ruptured proximal PICA aneurysms: a single-center 5-years experience.

Posterior inferior cerebellar artery (PICA) like other intracranial arteries is prone to aneurysm formation. Aneurysms usually arise from the vertebral artery (VA) - PICA junction and the proximal segment of the PICA. The use of endovascular treatment as an alternative treatment to surgery has been increasing. We present our last 5 years' experience in treating the ruptured proximal PICA aneurysms. Retrospective analysis of records of all patients with ruptured VA-PICA junction aneurysms treated at our referral center between July 2008 and July 2013 was performed. Over the last 5 years, we came across 17 patients who had aneurysms of proximal PICA or VA-PICA junction out of which 13 patients underwent endovascular treatment for ruptured saccular VA-PICA junction aneurysms and were the focus of this research. Follow-up studies ranged from 6 months to 3 years. All the patients presented with an acute intracranial hemorrhage on NCCT. All the aneurysms were at VA-PICA junction with partial or complete incorporation of PICA origin in the sac. Endovascular treatment of all the 13 aneurysm was successful in the first attempt. Aneurysms were treated with balloon assisted coiling either by placing the balloon across the VA-PICA junction (n = 3) or in the vertebral artery proper (n = 9). Stent assisted coiling VA-PICA was performed in one aneurysm (n = 1). There was no intra-procedural rupture of the aneurysms. Endovascular therapy of ruptured proximal PICA aneurysms is possible and safe with the use of adjuvant devices and should be considered as first line treatment.

Extracranially located PICA aneurysm presenting with supratentorial IVH: A rare event with diagnostic pitfalls

Extracranially located posterior inferior cerebellar artery (PICA) aneurysms are rare with only 21 cases reported till date. They may arise either from the proximal segment of an extracranially originating PICA or from the tip of its caudal loop when it dips below the foramen magnum. A 16-year-old female presenting with sudden onset severe headache and intraventricular hemorrhage (IVH) in the occipital horns of the lateral ventricle and the fourth ventricles, was diagnosed to have an extracranial proximal segment PICA aneurysm on a four vessel digital subtraction angiography (DSA), after initially missing it on the brain magnetic resonance imaging (MRI) with angiogram (MRA) because of its extracranial location. During surgery, the aneurysm was clipped following a far lateral suboccipital craniectomy with C1-C2 hemilaminectomy. The patient showed good recovery. Thus, we emphasize the need for a dedicated four vessel angiography to diagnose such lesions.

Stent-assisted coil embolization of wide-necked posterior inferior cerebellar artery aneurysms

Endovascular coil embolization of posterior circulation aneurysms has advantages over a surgical approach. However, the application of coil embolization is sometimes limited in wide-necked posterior inferior cerebellar artery (PICA) aneurysms, which are incorporating the origin of the branch. Presented here is a series of patients who were subjected to stent-supported coil embolization of PICA aneurysms. From a prospective data repository, we retrieved records of seven consecutive patients with PICA aneurysms, all of whom were treated by stent-assisted coil embolization between January 2010 and November 2012. Outcomes were analyzed in terms of aneurysm morphology and clinical status. In all seven instances, the stents were placed from proximal PICA to vertebral artery (VA). A retrograde approach, via contralateral VA, was performed in five patients, where the origin of PICA from VA assumed an acute angle. In the other two patients, where the angles were obtuse, the stenting was done antegrade, via ipsilateral VA. Out of five patients with retrograde approach, single puncture and a single guiding catheter sufficed in three patients, whereas the remaining two patients required dual puncture and two guiding catheters. Endovascular treatments, as performed, resulted in excellent outcomes for all seven patients, although an asymptomatic thrombus developed in one patient with a ruptured aneurysm. For coil embolization of PICA aneurysm requiring stent protection, either ipsilateral or contralateral VA access routes may be used, depending on the angle of PICA origin and the configuration of the aneurysm.

Endovascular treatment of proximal and distal posterior inferior cerebellar artery aneurysms

Surgical clipping of posterior inferior cerebellar artery (PICA) aneurysms can be challenging and carries a potentially significant risk of morbidity and mortality. Experience with endovascular therapy has been limited to a few studies. The authors assess the feasibility, safety, and efficacy of endovascular therapy in the largest series of proximal and distal PICA aneurysms to date. A total of 76 patients, 54 with proximal and 22 with distal PICA aneurysms, underwent endovascular treatment at Jefferson Hospital for Neuroscience between 2001 and 2011. Endovascular treatment was successful in 52 patients (96.3%) with proximal aneurysms and 19 patients (86.4%) with distal aneurysms. Treatment consisted of selective aneurysm coiling in 60 patients (84.5%) (including 4 with stent assistance and 4 with balloon assistance) and parent vessel trapping in 11 patients (15.5%). Specifically, a deconstructive procedure was necessary in 9.6% of proximal aneurysms (5 of 52) and 31.6% of distal aneurysms (6 of 19). There were 9 overall procedural complications (12.7%), 6 infarcts (8.5%; 4 occurring after deliberate occlusion of the PICA), and 3 intraprocedural ruptures (4.2%). The rate of procedure-related permanent morbidity was 2.8%. Complete aneurysm occlusion was achieved in 63.4% of patients (45 of 71). One patient (1.4%) treated with selective aneurysm coiling suffered a rehemorrhage on postoperative Day 15. The mean angiographic follow-up time was 17.2 months. Recurrence and re-treatment rates were, respectively, 20% and 17.1% for proximal aneurysms compared with 30.8% and 23.1% for distal aneurysms. Favorable outcomes (moderate, mild, or no disability) at follow-up were seen in 93% of patients with unruptured aneurysms and in 78.7% of those with ruptured aneurysms. Endovascular therapy is a feasible, safe, and effective treatment in patients with proximal and distal PICA aneurysms, providing excellent patient outcomes and adequate protection against rehemorrhage. The long-term incidence of aneurysm recanalization appears to be high, especially in distal aneurysms, and requires careful angiographic follow-up.

Operative Nuances of Side-to-Side In Situ Posterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Bypass Procedure

An intracranial posterior circulation revascularization procedure in the form of a side-to-side in situ posterior inferior cerebellar artery (PICA)-PICA bypass operation was introduced in 1991. This elegant and apparently low-risk operation is performed infrequently. Thus, the operative nuances used in this procedure have not been well reported, limiting the scope of treatment modalities of vertebral artery-PICA aneurysms and vertebral dissections. To repair an incidental right-sided PICA aneurysm noted in a 51-year-old woman in magnetic resonance imaging and subsequent angiography. The patient underwent side-to-side in situ PICA-PICA bypass surgery. Immediate indocyanine green angiography suggested that the PICA distal to the aneurysms was filling in a retrograde fashion through the bypass. On the following day, the patient was taken for coil embolization of the aneurysm. However, angiography images revealed that the aneurysm was spontaneously thrombosed, the proximal PICA was patent, and the PICA distal to the aneurysms was filling in a retrograde fashion, as suspected in intraoperative indocyanine green angiography. No further treatments were done. The patient recovered fully. We describe in detail the preoperative evaluation, decision process, and operative techniques for a side-to-side in situ PICA-PICA bypass operation, which is a relatively safe and elegant posterior circulation bypass procedure.

Ruptured Aneurysm Originating From an Aberrant Medullary Branch of the Proximal Posterior Inferior Cerebellar Artery

Aneurysms that arise from a small branch of the posterior inferior cerebellar artery (PICA) are very rare. All reported PICA branch aneurysms originated from the choroidal branches or PICA communicating branches. No aneurysms of the PICA medullary branch have been reported previously. A 62-year-old woman presented with a subarachnoid hemorrhage and intraventricular hemorrhage. Angiography showed a globular-shaped aneurysm arising from an aberrant branch of the anterior medullary segment of the left PICA. At the time of operation, the arterial branch was found to send some perforators into to the medulla oblongata and cervical spinal cord. Aneurysm trapping was performed. Postoperatively, the patient had a mild transient difficulty in swallowing that may have been caused by manipulation of the vagus nerve rootlets. Aneurysms can develop from a proximal medullary branch of the PICA and lead to subarachnoid hemorrhage and intraventricular hemorrhage. Trapping can be judiciously attempted to treat this precarious aneurysm.

POSTERIOR INFERIOR CEREBELLAR ARTERY ORIGIN THROMBOSIS WITH ANEURYSM OF COLLATERALIZED POSTERIOR MENINGEAL ARTERY PRESENTING AS SUBARACHNOID HEMORRHAGE

This is the first report of a ruptured aneurysm involving a collateral branch to the posterior inferior cerebellar artery (PICA) in a patient who had a subarachnoid hemorrhage. A 56-year-old man initially presented with a subarachnoid hemorrhage and underwent 2 catheter-based 4-vessel angiograms with negative results. A delayed angiogram 4 weeks later revealed a dissecting aneurysm of the posterior meningeal artery, a branch of the vertebral artery. A 3-dimensional reconstruction of the vertebral angiogram showed proximal occlusion of the proximal left PICA and distal filling via a collateral branch from the posterior meningeal artery. A far-lateral approach was used for this patient. The aneurysm was found along the course of the collateral posterior meningeal artery and was clipped successfully. Aneurysms involving collateral branches of the PICA are rare. It is important to recognize such collateral flow preoperatively because inadvertent sacrifice of these vessels during a surgical approach could lead to stroke and neurological deficits of the PICA territory.

Diagnosis and surgical management of extracranial PICA aneurysms presenting through subarachnoid haemorrhage: Case report and review of the literature

Objective and importance We present a very unusual case in which a proximal posterior inferior cerebellar artery (PICA) aneurysm was located extracranially. We reviewed the PICA origin anatomy and pathology of aneurysms at this site. Clinical presentation A Caucasian woman, 52 years of age, presented with a lesion at the craniocervical junction. She complained only of headache off and on without other symptoms. Her physical examination was unremarkable. A CT angiography clearly visualized an approximately 9-mm wide aneurysm of the right PICA which lay intradurally in the spinal canal at the C 1-level. Surgery was planned. However, six weeks after her initial referral and just before her surgical date, the patient suffered a subarachnoid haemorrhage. Physical examination at that time showed a lethargic but conscious patient, with slight disorientation (Glasgow Coma Score 14; Hunt and Hess grade III). Intervention The aneurysm was successfully treated by microneurosurgical techniques via a suboccipital craniotomy with laminectomy of C 1 as well. Temporary clipping of the PICA was feasible and the aneurysm could be dissected and clipped appropriately. Conclusion The present report underscores the anatomical variants of the PICA. Although uncommon, PICA aneurysms do occur and caretakers should be aware of this when treating patients with clinical signs or CT evidence of subarachnoid haemorrhage. Even extracranial PICA aneurysms can be encountered, either through a caudal loop or an early extracranial lateral medullary segment. We stress the use of four vessel angiography or CT angiography with thin cuts to rule out such aneurysms.

Remote distal outflow occlusion: a novel treatment option for complex dissecting aneurysms of the posterior inferior cerebellar artery

The authors report a novel management option for patients with complex dissecting aneurysms of the posterior inferior cerebellar artery (PICA). The authors reviewed the medical records and neuroimaging studies of 3 patients who underwent a novel surgical treatment for complicated dissecting PICA aneurysms. The mean follow-up period was 1.1 years, and no patient was lost to follow-up. Two patients were in poor condition following an acute, severe subarachnoid hemorrhage, and 1 presented with headaches and a remote history of bleeding. All patients underwent surgical occlusion of the PICA beyond the tonsillar loop, distal to the aneurysmal segment. Intraoperative and delayed follow-up angiography demonstrated progressive diminution in size of the aneurysmal dilation but persistent filling of the proximal PICA segments supplying the brainstem. Outcome was good in all cases. This novel technique has been used successfully in 3 cases and, to the authors' knowledge, has not been reported previously.

Delayed post-traumatic saccular aneurysm of PICA in an adolescent

Delayed traumatic intracranial aneurysms of the posterior circulation caused by nonpenetrating head injury are rare, especially in pediatric patients. The true incidence and natural history of these aneurysms are poorly understood. We report a case of a 15-year-old boy who initially presented with subarachnoid hemorrhage of the posterior fossa without any evidence of associated aneurysm. On a routine computed tomography of the head, however, he was found to have a saccular aneurysm of the proximal posterior inferior cerebellar artery. The patient was treated successfully by microsurgical clipping and PICA/PICA bypass.

Surgical treatment for posterior inferior cerebellar artery aneurysms

Objective To explore the clinical characteristics and surgical managements of posterior inferior cerebellar artery (PICA) aneurysms. Methods Retrospective analysis of the clinical features, imaging characteristics and clipping results of 21 PICA artery aneurysms. This series included 9 men and 12 women, mean age was 40.6 years. One presented with mass pressure effects of infrotentoria fossa; 20 patients presented with severe and sudden onset of symptoms, reflecting a hemorrhage from a PICA aneurysm. Hunt-Hess and Hess grades at presentation were: Grade Ⅰ in 1 patient, Grade Ⅱ in 14 patients, Grade Ⅲ in 5 patients, Grade Ⅳ in 1 patient. The bleeding was confined to the infrotentoria subarachnoid space (SAH) and/or the fourth ventricle. Arteriographies revealed 13 proximal PICA aneurysms and 8 distal PICA aneurysms. Results Lateral suboccipital and midline suboccipital surgical approaches were used to secure the aneurysms in all patients, either by direct clipping in 19 cases, parent artery's occlusion in 1 case and parent artery's sacrifice in 1 case. Transient CSF leak occurred in 3 patents; paresis and lower cranial nerve dysfunction and long-term coma occurred in 1 patient; mild lower cranial nerve dysfunctions occurred in 2 patients, and had good recovery at 3 months of follow-up; no complication in other patients. Conclusions The favorable outcomes and low postoperative morbidity in our patients argues that surgical clipping be considered a first-line therapeutic option. The protection of the low cranial nerves and the preservations of PICA are major contributors to good long-term results. Key words: Posteroinferior cerebellar artery; Aneurysm clipping; Subarachnoid hemorrhage