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 »  Abstract
 »  Introduction
 »  Case report
 »  Results
 »  Discussion
 »  References

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Year : 2000  |  Volume : 48  |  Issue : 2  |  Page : 161-3

Vertebral artery aneurysms.


Department of Neurosurgery, Sri Venkateswara Institute of Medical Sciences, Tirupati, 517507, India.

Correspondence Address:
Department of Neurosurgery, Sri Venkateswara Institute of Medical Sciences, Tirupati, 517507, India.

  »  Abstract

Vertebral artery (VA) aneurysms are rare. We present our experience with three cases of VA aneurysms. Two aneurysms were located close to the origin of basilar artery while the third patient had a giant posterior inferior cerebellar artery aneurysm. These aneurysms were operated by the far lateral inferior suboccipital approach with good results.

How to cite this article:
Ravi Kumar C V, Palur R S, Satish S, Rao B R. Vertebral artery aneurysms. Neurol India 2000;48:161


How to cite this URL:
Ravi Kumar C V, Palur R S, Satish S, Rao B R. Vertebral artery aneurysms. Neurol India [serial online] 2000 [cited 2020 Oct 29];48:161. Available from: https://www.neurologyindia.com/text.asp?2000/48/2/161/1554




   »   Introduction Top

Vertebral artery (VA) aneurysms constitute 0.5 to 3% of intracranial aneurysms and 20% of posterior circulation aneurysms.[1] They pose significant challenge due to difficulty in the surgical approach, which is further enhanced by the relative inexperience of most neurosurgeons with these lesions due to their rarity. These aneurysms are usually located at the vertebral artery - posterior inferior cerebellar artery (VA-PICA) junction and are more easier to access than those situated more distally along the VA, close to the basilar artery (BA) origin. We report three cases of VA aneurysms managed during the past three and half years. Two aneurysms were located near the origin of BA and the other was a giant PICA aneurysm. These aneurysms were clipped using far lateral inferior suboccipital approach.[2]


   »   Case report Top

Case 1: A 45 year old male patient presented with a history of sudden onset of headache, neck pain, generalized seizures, right sided weakness and altered sensorium of five days duration. On examination, he was drowsy and irritable. Fundus examination revealed right retinal haemorrhages. He had mild right hand grip weakness and the power in right lower limb was 0/5 MRC grade. He also had positive meningeal signs. CT scan showed blood in the fourth ventricle. Four vessel cerebral DSA revealed right VA aneurysm arising distal to the PICA, near the VA-BA junction [Figure - 1]. The aneurysm was clipped using the far lateral inferior suboccipital approach. He developed lower cranial nerve paresis following surgery that improved over a period of three weeks. Three months later, he was able to walk without support and had grade 4 MRC power in right lower limb and was independent for activities of daily living (ADL).
Case 2: A 16 year old male patient presented with history of progressive unsteadiness of gait associated with swaying to right side while walking, for the past one year; right sided tinnitus, deafness associated with diffuse headache since six months and vomiting for the past four days. On examination, he was conscious, oriented and fundus examination was normal. He had right V, VIII and lower cranial nerve deficits in addition to right sided cerebellar signs. CT scan of the brain showed a large well circumscribed hyperdense lesion in the right cerebellopontine (CP) angle extending superiorly towards the midline. The lesion did not exhibit contrast enhancement. The conFigureuration of the lesion was well defined by the 3D CT scan which showed that it was situated near the anterior and left lateral rim of the foramen magnum extending superiorly towards the midline of posterior fossa [Figure. 2]. DSA revealed that right PICA was not visualized. At surgery, the lesion turned out to be a giant PICA aneurysm arising 1.5 to 2 cm from the VA-PICA junction. The aneurysm had nearly thrombosed. The aneurysm was trap ligated by proximal and distal clipping and excised. Postoperatively, the patient developed facial paresis in addition to worsening of his lower cranial nerve deficits, which gradually improved. Two years later, he had completely recovered and was without neurological deficits.
Case 3: A 55 year old lady was referred with history of sudden headache, neck pain, vomiting, left sided weakness associated with altered sensorium of five days duration. She was a known hypertensive on irregular treatment. Twenty years ago, she had sudden headache associated with left sided hemiplegia that had improved over a period of six months. On examination, she was confused, had right lateral rectus palsy, left UMN facial paresis and left hemiplegia (MRC grade 0/5). CT scan revealed diffuse subarachnoid haemorrhage, intraventricular haemorrhage with blood in the upper brainstem. DSA showed right VA aneurysm arising close to the VA-BA junction. In addition, both her internal carotid arteries (ICA) were occluded and both VAs were supplying the anterior circulation. The aneurysm was clipped uneventfully. Patient developed lower cranial nerve palsy postoperatively, which gradually improved and her hemiplegia improved to grade 2/5.


   »   Discussion Top

VA aneurysms arising from the distal intradural vertebral artery in two patients and a giant PICA aneurysm have been presented. These aneurysms are relatively uncommon, constituting 0.5 to 3% of all intracranial aneurysms.1 VA aneurysms include VA-PICA aneurysms, vertebro-basilar junction aneurysms, distal PICA aneurysms, distal PICA aneurysms and those located along the distal VA. Two thirds of these aneurysms reside on the intracranial VA adjacent to the origin of the PICA. Distal VA aneurysms and giant aneurysms in this location are rare.[3],[4],[5] The natural history of these aneurysms is dismal.[1] Microsurgical clipping of the neck remains the mainstay of treatment, as in all cases of intracranial aneurysms. However, ruptured posterior circulation aneurysms are technically difficult to expose and clip and their management and surgical outcomes are poorer as compared to anterior circulation aneurysms.[6] They often need expertise with various skull base approaches to improve the exposure, to minimize brain retraction and to achieve better outcome.[7] Certain subset of posterior circulation aneurysms are considered at even higher risk for surgery due to their location and the size, prompting recourse to other modalities of therapy viz. endovascular coil occlusion.[6] The patients presented here belong to this subset due to their location close to BA in two cases and the size in the third. However, endovascular therapy is available in very few centers in India and at present is prohibitively expensive, thus mandating the difficult surgical treatment.
Two patients reported here (Case 1 and 3), presented with subarachnoid haemorrhage and significant hemiparesis which had improved after surgery. They had VA aneurysms close to the BA origin thereby making the approach arduous. In addition, Case 3 had bilateral ICA block rendering temporary clipping of VA dangerous. The operative corridor used was the far lateral inferior suboccipital approach as described by Heros,[2] which offered excellent exposure and the aneurysms could be clipped successfully with minimal brain retraction. However, as the dissection proceeds in between the rootlets of lower cranial nerves, all patients had lower cranial nerve paresis postoperatively, though fortunately transient. Other surgeons, might have chosen a different corridor of approach while dealing with these aneurysms but the risk of the nerve palsy remains.[7] The third patient had a thrombosed giant PICA aneurysm presenting clinically with CP angle syndrome. 3D CT scan delineated the relation of the lesion to foramen magnum, brain stem and 4h ventricle. Angiogram did not demonstrate the aneurysm as it had thrombosed. This patient was successfully managed by thrombectomy via cerebellomedullary and cerebellopontine cisterns and complete excision of aneurysm with proximal and distal clipping of the parent artery.
Giant PICA aneurysms are infrequent.[5] The surgical problems with these aneurysms are that of decompression of the mass and maintenance of vascular integrity. Various surgeons have used different strategies in dealing with these issues.[4],[5],[8] Kurokawa et al have suggested different approaches for thrombectomy and neck clipping. They performed transcerebellar thrombectomy using ultrasonic surgical aspirator and clipped the aneurysmal neck in the cerebellomedullary cistern.[4] This method may be useful if the cerebellum is tense, defying retraction. In our patient though the aneurysm was large, thrombectomy could be performed through the cistern after retracting the cerebellum, creating a large working space as the surgery progressed. The aneurysm was near totally thrombosed and was arising 1.5 to 2 cm of the origin of PICA from the VA. At the end of the decompression, the proximal and distal PICA was clipped and the intervening portion of PICA from which the aneurysm originated was excised. There was brisk bleeding from distal stump suggesting good collateral flow. As preoperative angiogram did not opacify the aneurysm, it was presumed to be totally thrombosed and hence trap ligation with excision was performed without undue fear of neurological deterioration.
The major morbidity with far lateral inferior suboccipital approach seems to be the lower cranial nerve palsy, which recovers. The overall results are good.

Addendum
Since submitting the manuscript for consideration for publication, another patient with distal vertebral artery aneurysm was operated using the far lateral approach. A 55 year old female patient presented with SAH grade II. A large distal vertebral aneurysm arising from right vertebral artery distal to the PICA origin with fundus directed medially, inferiorly and anteriorly was demonstrated by angiogram which was clipped successfully.

 

  »   References Top

1.Ausman JI, Sadasivan B: Posterior inferior cerebellar arteryvertebral artery aneusysms, Brain Surgery Complication Avoidance and Management, Apuzzo M LJ, Churchill Livingstone, New York, 1993; 2: 1879-1894.   Back to cited text no. 1    
2.Heros RC: The far lateral inferior suboccipital approach, Neurosurgery, Wilkings RH, Rengachary SS, II Edition, McGraw-Hill, New York, 1996; 2: 2357-2360.   Back to cited text no. 2    
3.Day DJ , Giannotta SL: Surgical management of vertebro-PICA aneurysms, Operative Neurosurgical Techniques, Schmidek HH, Sweet WH, WB Saunders Company, Philadelphia, 1995; 1: 1103-1111.   Back to cited text no. 3    
4.Kurokawa Y, Okamura T, Watanabe K: Transcerebellar thrombectomy for the successful clipping of thrombosed giant Vertebral artery-Posterior inferior cerebellar artery aneusysm: Case Report. Surg Neurol 1990; 33: 217-220.   Back to cited text no. 4    
5.Madsen JR, Heros RC: Giant peripheral aneurysm of the posterior inferior cerebellar artery treated with excision and end-to-end anastomosis. Surg Neurol 1988; 30: 140-143.   Back to cited text no. 5    
6.Nichols DA, Brown RD, Thielen KR et al: Endovascular treatment of ruptured posterior circulation aneurysms using electrolytically detachable coils. J Neurosurg 1997; 87: 374-380.   Back to cited text no. 6    
7.Day DJ, Fukushima T, Giannotta SL: Cranial base approaches to posterior circulation aneurysms. J Neurosurg 1997; 87: 544-554.   Back to cited text no. 7    
8.Ausman Jl, Diaz FG, Mullan S et al: Posterior inferior to posterior inferior cerebellar artery anastomosis combined with trapping for vertebral artery aneurysm. J Neurosurg 1990; 73: 462-465.   Back to cited text no. 8    

 

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