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

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.     

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.     

Relationship between angiographical manifestations and operative findings in 100 cases of hemifacial spasm

Relationship between angiographical manifestations and operative findings of hemifacial spasm was studied in 100 cases. Vertebral angiography was performed, and Towne, straight AP, and lateral projections were routinely studied. The anterior inferior cerebellar artery (AICA) directly compressed the facial nerve root exit zone in 54 instances, the posterior inferior cerebellar artery (PICA) in 38, and the vertebral artery (VA) in 11. Compressions by multiple vessels were observed in 3 cases. Anatomical variations of the AICA and the PICA were classified into 3 groups according to their origins and their distributions of blood supply: Type I, normal distribution of AICA and PICA; Type II, common trunk anomaly with dominant AICA (basilar artery origin); and Type III, common trunk anomaly with dominant PICA (vertebral artery origin). In our cases, 35% of them showed normal distribution, 34% dominant AICA, and 35% dominant PICA. Analyses of the angiograms revealed significantly increased numbers of common trunk anomalies when compared with normal angiograms studied by Takahashi. In 60 of the 65 cases with common trunk anomalies, facial nerves were compressed by the main trunk or the branches of the dominant artery. There were 35 cases which belonged to Type I anatomical classification. They were subdivided into 2 groups according to the size of the AICA and PICA: 1. AICA greater than PICA, and, 2. PICA greater than AICA. In the AICA greater than PICA subgroup, the AICA was the offending artery in all but one case. In the PICA greater than AICA subgroup, the PICA was responsible in 9 of 17 cases. In 31 cases, angiograms showed a redundant VA with lateral elongation into the cerebellopontine angle.(ABSTRACT TRUNCATED AT 250 WORDS)     

Development of unusual collateral channel from the posterior meningeal artery after endovascular proximal occlusion of the posterior inferior cerebellar artery

A 38-year-old man presented with a dissecting aneurysm of the left proximal posterior inferior cerebellar artery (PICA) manifesting as Wallenberg's syndrome. The patient was treated by endovascular occlusion of the aneurysm and parent artery. Immediately after the treatment, the PICA territory was supplied by collateral circulation via the ipsilateral anterior inferior cerebellar artery. Seven days later, endogenous revascularization of the distal PICA territory had occurred via collateral circulation from the posterior meningeal artery (PMA). This unusual collateral circulation was thought to occur through a pre-existing anastomotic channel between the primitive vessels of the PICA and the PMA during subclinical hypoperfusion of the distal PICA territory. This unusual case demonstrates the potential for delayed development of collateral circulation from the PMA to the PICA territory.     

Vertebral artery-posterior inferior cerebellar artery bypass with a superficial temporal artery graft to treat aneurysms involving the posterior inferior cerebellar artery

OBJECT: In patients with aneurysms that require occlusion of the posterior inferior cerebellar artery (PICA), revascularization of this artery should be performed. A novel surgical method for revascularization of the PICA is presented. METHODS: After a segment of the superficial temporal artery (STA) was harvested, the aneurysm was treated by trapping, followed by placement of a vertebral artery (VA)-PICA bypass in which the STA segment was used as a graft. When the length of the proximal PICA was inadequate, the distal end of the STA was anastomosed to the proximal PICA in an end-to-side fashion. When the length of the proximal PICA was adequate, the STA was anastomosed to the proximal PICA in an end-to-end fashion. In either case, the proximal end of the STA was anastomosed to the VA in an end-to-side fashion. This procedure was used in nine patients whose aneurysms involved the PICA. Although partial lateral medullary syndrome developed in one of them, follow-up evaluation revealed graft patency in all patients. There were no instances of recurrent hemorrhage or ischemia. CONCLUSIONS: Although this procedure requires harvesting of an STA graft and two anastomoses, it facilitates anterograde flow to the PICA territory. It also involves minimal mobilization of brainstem perforating vessels and the proximal PICA.     

Posterior inferior to posterior inferior cerebellar artery anastomosis combined with trapping for vertebral artery aneurysm. Case report

A case is presented in which a giant intracranial vertebral artery aneurysm gave rise to an associated ipsilateral posterior inferior cerebellar artery (PICA) from its waist. Proximal vertebral artery ligation at C-1 was achieved. The aneurysm filled from the opposite vertebrobasilar junction. Direct intracranial trapping of the right vertebral aneurysm was followed by successful anastomosis of the proximally sectioned right PICA to the adjacent left PICA in an end-to-end fashion.     

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.     

Dissecting Aneurysm of the Peripheral Posterior Inferior Cerebellar Artery

Dissecting aneurysms of intracranial posterior circulation have recently been shown to be less uncommon than previously thought. However, those involving the posterior inferior cerebellar artery (PICA) and not vertebral artery at all are extremely rare. We report here a case of a patient with a dissecting aneurysm of the lateral medullary segment of PICA which presented as subarachnoid haemorrhage. The aneurysm was treated by trapping surgery and the distant PICA was anastomosed to the occipital artery. The patient showed a slight ataxia immediately after surgery but recovered fully. Recovery from immediately postoperative cerebellar symptoms due to intra-operative ischemia seemed to be due largely to recovery of flow in the region of cortical branches of PICA.     

Ruptured aneurysm of a posterior inferior cerebellar artery communicating artery. Case report and histological findings

A hypertensive 60-year-old man presented with a rare aneurysm arising from the posterior inferior cerebellar artery (PICA) communicating artery, manifesting as subarachnoid hemorrhage with intraventricular hemorrhage. Angiography showed a small aneurysm arising from a fine and tortuous artery interconnecting the bilateral vermian branches of distal PICAs. The right PICA was absent and its vermian territory was supplied by the left PICA through this communicating artery. The right anterior inferior cerebellar artery was also connected to the vermian branch of the right PICA. At surgery, a reddish and apparent fusiform aneurysm was noted at the top of the arterial loop under the cerebellar vermis. Microsurgical trapping and removal of the aneurysm was performed without complication. Histological examination demonstrated typical findings of a true aneurysm. Only four previous cases of aneurysm of the communicating artery between the bilateral distal PICAs have been reported. In all five reported cases including ours, the PICA communicating artery contributed to the collateral blood supply of the contralateral vermian territory based on vascular anomalies. Hemodynamic stress and congenital vulnerability may have caused this aneurysm. Trapping is suitable to treat this precarious aneurysm if other collateral vessels supply the contralateral vermian territory.     

Peripheral aneurysms of the posterior inferior cerebellar artery

Nonmycotic peripheral posterior inferior cerebellar artery (PICA) aneurysms are rare. The authors report six cases of peripheral PICA aneurysm. Two of these are unusual; one was fusiform and another was a double aneurysm arising from the peripheral PICA. The previously reported 40 cases of peripheral PICA aneurysm are reviewed.     

3D Computer graphics simulation to obtain optimal surgical exposure during microvascular decompression of the glossopharyngeal nerve

The affected artery in glossopharyngeal neuralgia (GPN) is most often the posterior inferior cerebellar artery (PICA) from the caudal side or the anterior inferior cerebellar artery (AICA) from the rostral side. This technical report describes two representative cases of GPN, one with PICA as the affected artery and the other with AICA, and demonstrates the optimal approach for each affected artery. We used 3D computer graphics (3D CG) simulation to consider the ideal transposition of the affected artery in any position and approach. Subsequently, we performed microvascular decompression (MVD) surgery based on this simulation. For PICA, we used the transcondylar fossa approach in the lateral recumbent position, very close to the prone position, with the patient’s head tilted anteriorly for caudal transposition of PICA. In contrast, for AICA, we adopted a lateral suboccipital approach with opening of the lateral cerebellomedullary fissure, to visualize better the root entry zone of the glossopharyngeal nerve and to obtain a wide working space in the cerebellomedullary cistern, for rostral transposition of AICA. Both procedures were performed successfully. The best surgical approach for MVD in patients with GPN is contingent on the affected artery—PICA or AICA. 3D CG simulation provides tailored approach for MVD of the glossopharyngeal nerve, thereby ensuring optimal surgical exposure.     

Clinical presentation and surgical management of dissecting posterior inferior cerebellar artery aneurysms: 2 case reports

Intracranial dissection presenting with subarachnoid hemorrhage (SAH) most commonly involves the vertebral artery. The natural history of this lesion suggests frequent early rehemorrhage and need for urgent treatment. Isolated dissection of the posterior inferior cerebellar artery (PICA) is very rare. We present 2 cases of isolated PICA dissections presenting with SAH. Both patients were middle-aged men who presented with transient loss of consciousness, severe headache, and cranial neuropathies. Initial angiography showed dilatation and narrowing of PICA consistent with dissection and aneurysm formation. The vertebral arteries were normal and there was no other cause for the SAH. Repeat angiography 2 weeks after admission revealed significant enlargement of the aneurysmal dilation of the dissected segment of PICA in both patients. Both patients were treated operatively. One patient had clip reconstruction of the PICA with preservation of flow through the PICA. Follow-up angiography one year later showed no recurrence. The other patient underwent direct surgical trapping and resection of the dissected segment of PICA after passing balloon occlusion testing at the vertebral-PICA junction. Both patients have more than 2 years of clinical follow-up and remain well. Isolated PICA dissection seems to have a less ominous natural history compared to vertebral artery dissection. These lesions need to be followed carefully for evidence of aneurysmal enlargement. Direct surgical reconstruction of the dissected segment may be possible. Balloon occlusion testing may be very helpful in determining if the involved PICA segment can be sacrificed.     

小脑后下动脉的显微解剖研究及其临床意义

目的 研究小脑后下动脉的显微解剖,为神经外科手术提供临床解剖资料.方法 手术显微镜下观察测量20具(共40侧)人脑标本的小脑后下动脉(PICA)的起始行径、直径、主要分支、穿动脉及分布,检查PICA与脑神经根的关系.结果 40侧标本共发出PICA 35支,平均管径(1.6±0.6)mm,距离椎基底动脉汇合点平均(16±5)mm.在35支PICA中28支PICA走行在第Ⅻ脑神经根之间,7支走行在第Ⅻ脑神经根下方,32支走行在第Ⅺ脑神经根之间.结论 PICA是椎基动脉系统重要的分支,变异多,走行与脑神经关系密切,熟悉解剖结构,在后颅窝手术中予以保护具有重要意义.     

A "PICA communicating artery" aneurysm: case report.

We present an unusual case of an aneurysm of the distal posterior inferior cerebellar artery (PICA). The aneurysm was associated with a unilateral PICA that supplied both cerebellar hemispheres and arose from an anastomotic vessel to the contralateral circulation, a branch of the contralateral PICA. Such an aneurysm has not been reported previously. The associated of vascular anomalies with aneurysms of the PICA is discussed.     

Multiple spontaneous dissecting aneurysms of the anterior cerebral and vertebral arteries

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

Aneurysm of the distal posterior inferior cerebellar artery originating from the extracranial and extradural vertebral artery

A 42-year-old woman presented with a ruptured aneurysm of the distal posterior inferior cerebellar artery (PICA), which had a rare extracranial and extradural origin. Medial suboccipital craniectomy and C-1 laminectomy were performed. The aneurysm had adhered to the right cerebellar tonsil, but was successfully clipped without difficulty. Intraoperatively, the PICA origin was recognized in the extracranial and extradural space between the dorsal roots of the C-1 and C-2 nerves. The origin of the PICA from the vertebral artery (VA) may occur at any portion of the VA from the site of penetration of the dura to the vertebrobasilar junction, but an extradural origin is uncommon. A ruptured aneurysm of the PICA branching from the VA at a site proximal to the vertebrobasilar junction and below the foramen magnum may be overlooked by three-vessel angiography if the contrast medium cannot reflux to the contralateral PICA origin.     

Treatment of vertebral artery aneurysms with posterior inferior cerebellar artery-posterior inferior cerebellar artery anastomosis combined with parent artery occlusion

BACKGROUND: In patients with aneurysms that involve the origin of the posterior inferior cerebellar artery (PICA) and require occlusion of the vertebral artery (VA), revascularization of the PICA is commonly performed. We present six patients with dissecting VA aneurysms who underwent PICA-PICA anastomosis combined with parent artery occlusion. METHODS: After a lower lateral suboccipital craniectomy and partial resection of the jugular tubercle, anastomoses were performed in a side-to-side fashion at the posterior medullary segment of the PICA. The VA was subsequently occluded by clipping proximal and distal to the aneurysm, and the PICA was occluded by clipping distal to the aneurysm. RESULTS: Postoperative cerebral angiography demonstrated patency of the anastomosis and regression of the aneurysm in five of six patients. The remaining patient experienced hemorrhage from contralateral VA dissection and subsequently died. One patient experienced myopathy of the lower extremities secondary to intraoperative fixed board compression and developed permanent lower extremity muscular weakness. The remaining four cases experienced no new neurologic deficits. CONCLUSION: PICA-PICA anastomosis is a useful procedure for reconstruction of the PICA when parent vessel occlusion or trapping is necessary to exclude a VA aneurysm involving the origin of the PICA.     

Vertebral artery occlusion with vertebral artery-to-posterior inferior cerebellar artery stenting for preservation of the PICA in treating ruptured vertebral artery dissection

We report a patient with a right vertebral artery (VA) dissecting aneurysm who was treated by placing an Enterprise stent (Cordis Neurovascular, Miami Lakes, FL) from the proximal VA to the posterior inferior cerebellar artery (PICA) in order to save the patency of the PICA. A 47-year-old man was admitted with a ruptured right VA dissecting aneurysm that involved the origin of the PICA. A 4.5 × 37-mm Enterprise stent was then placed through the proximal VA to the PICA. The dissected segment of the VA was completely occluded by coil embolization. The 1-year follow-up angiography showed that the dissected segment was completely occluded and the diameter of the PICA was slightly increased, and the PICA’s patency was good.     

About a very rare variation of the course and width of the vertebral arteries and the hypoglossal nerve

Described are: 1. A very thin intracisternal part of the vertebral artery (0.9 mm). 2. A very rare course of the vertebral artery (dorsal to the hypoglossal nerve). 3. Rare anastomoses between the vertebral artery and the PICA. 4. A rare upwards coiling of the PICA and 5. The origin and prevertebral course of the vertebral arteries.     

Ruptured aneurysm at an anastomotic artery extending from the vertebral artery to the posterior inferior cerebellar artery: a case report

A 51-year-old hypertensive man presented with subarachnoid haemorrhage. He had a past history of cerebellar infarction due to occlusion of the right posterior inferior cerebellar artery (PICA) 4 years earlier. Digital subtraction angiography showed a saccular aneurysm above an arterial loop extending from the vertebral artery to the distal part of the PICA, reminiscent of peripheral PICA branches. We performed aneurysmal neck clipping with excellent outcome. Aneurysms at anastomotic arteries are extremely rare and can result from increased haemodynamic stress. We report the first case of a ruptured aneurysm at an anastomotic artery in the posterior circulation territory.