Isolated ruptured dissecting aneurysm of PICA with extremely narrow neck managed by a novel endovascular technique-a case report and review of literature

Dissecting aneurysms of posterior inferior cerebellar artery (PICA) are usually extensions of vertebral artery dissection. Isolated dissecting aneurysms of PICA are extremely rare. A 5-month-old female child presented with history of fall from a height of around 2 ft., followed by incessant crying and multiple episodes of vomiting. The anterior fontanelle was lax. Plain CT scan brain showed IVH in the fourth ventricle with no hydrocephalus. Twenty-four hours after admission, the child had one episode of vomiting and became unresponsive. The child was intubated, and a repeat CT scan brain showed thick acute SDH in the posterior fossa with hydrocephalus. Emergency suboccipital craniectomy and evacuation of thick acute subdural hematoma were done. Organized clot noted in the midline between the tonsils was not removed. Digital subtraction angiography (DSA) done 48 h after surgery showed ruptured dissecting aneurysm of left PICA. Endovascular temporary parent artery occlusion by coil deployment was performed, after which a check angiogram revealed complete exclusion of aneurysm from circulation. Endovascular proximal parent artery occlusion is the preferred treatment modality for dissecting aneurysms of PICA. Selective coil or Onyx embolization of the aneurysm with parent vessel preservation technique is a valid and increasingly used alternative. In this case, a novel technique of endovascular temporary parent artery occlusion by coil deployment was performed successfully. This technique may be recommended in select cases.

"Sit back, observe, and wait." Or is there a pharmacologic preventive treatment for cerebral aneurysms?

Intracranial aneurysms (IA) are a relatively frequent vascular abnormality. The prevailing opinion is that cerebral aneurysmal disease is related to hemodynamic and genetic factors, associated with structural weakness in the arterial wall which was acquired by a specific, often unknown, event. Possibly the trigger moment of aneurysm formation may depend on the dynamic arterial growth, which is closely related to aging/atherosclerosis. In most individuals, an endovascular/microsurgical approach is possible in order to obliterate the IA. However, in a number of patients with an unruptured IA (UIA), the neurosurgeon's decision is to just "sit back, observe, and wait", based on the favorable natural history of some of the UIAs. Furthermore, some individuals need to be kept under close observation since they have a higher chance of developing IA, especially those with at least two affected first-degree relatives with an IA, subjects with polycystic kidney disease, and patients who have undergone an aneurysm intervention. In these examples prophylactic strategies should be adopted, if it is at all possible. The main question is deciding the best option of clinical treatment for these cases, when surgical approach is contraindicated, or for those subjects who are more prone to develop an IA. In the present article, we hypothetically suggest a pharmacologic form of treatment with statins, beta-adrenergic blocker agents, and/or angiotensin-converting-enzyme inhibitor/angiotensin II receptor blockers to inhibit or slow down IA formation, taking into consideration some pathophysiological aspects related to aneurysmal development, such as: hemodynamic stress, arterial wall inflammation, nitric oxide formation, and atheromatous disease.

Spontaneous resolution of isolated dissecting aneurysm on the posterior inferior cerebellar artery

The authors report a rare example of an isolated dissecting posterior inferior cerebellar artery (PICA) aneurysm with spontaneous resolution. A 41 year-old male suffered sudden dizziness, nausea and vomiting. An angiogram and magnetic resonance imaging (MRI) detected an isolated PICA dissection. The patient was treated conservatively and recovered without any apparent neurological deficit. MRI detected the self-resolution of the dissecting aneurysm. Dissecting PICA aneurysms, especially non-haemorrhagic lesions, have the possibility of spontaneous resolution resulting in a favorable outcome. The treatment strategy for this vascular lesion may be decided based upon neuroradiological changes on careful follow-up.

Management of spontaneous haemorrhagic intracranial vertebrobasilar dissection: review of 21 consecutive cases

INTRODUCTION

Haemorrhagic intracranial vertebrobasilar dissection is an uncommon cause of nontraumatic subarachnoid haemorrhage (SAH) and accounts for only 1-10% of non-traumatic SAH. Treatment in the acute phase is considered to be essential because of the high risk of rebleeding and the consequent unfavourable outcome. However, the location, the potential for involvement of eloquent vessels and the histopathological characteristics of the vessel wall make treatment demanding from both a technical and anatomical point of view. We report our experience in the management of this disease. PATIENTS AND TREATMENTS: From 1989 to June 2006, we managed 21 patients with spontaneous haemorrhagic dissection located in the intracranial vertebrobasilar system, 13 patients were treated using an endovascular approach, 1 by surgical clipping, and 7 were managed conservatively.

RESULTS

Among the 13 patients treated endovascularly, 7 underwent proximal occlusion, 4 underwent parent artery embolization at the site of dissection, and 2 underwent endovascular trapping. Severe, treatment-related complications due to dislodgement of the thrombus during the procedure occurred in 1 patient, who then died from brainstem ischaemia. One patient died from severe pneumonia and one patient was left disabled from vasospastic ischaemia resulting from severe initial SAH. The remaining 10 patients had satisfactory outcomes: none rebled after treatment and when discharged they had Karnovsky scores of 80-100. Of the 7 conservatively treated patients, three died of rebleeding and four were discharged with Karnovsky scores of 50-100. One patient, who was treated surgically, was discharged with a Karnovsky of 90.

CONCLUSION

The high rate of rebleeding and consequent mortality among the patients treated conservatively argues for treatment in the acute phase. Treatment should be guided by each patient's angiomorphology, clinical condition and the experience of the neurosurgical/neuroradiological team. Options include endovascular or surgical trapping of the dissection and proximal occlusion and embolisation of the parent artery at the site of the dissection.

Paediatric dissecting posterior cerebral aneurysms: report of two cases and review of the literature

INTRODUCTION

Intracranial aneurysms in the paediatric population are uncommon, accounting for 2% to 6% of all aneurysms, and spontaneous arterial dissection is rarely reported as the cause of aneurysms in children, especially in the posterior cerebral artery.

METHODS

Two cases of paediatric spontaneous posterior cerebral artery dissecting aneurysms are reported, one in a 33-month-old male child presenting with aneurysmal rupture and subarachnoid haemorrhage and the other in a 9-year-old boy with an unruptured aneurysm.

RESULTS

The first child was successfully treated by endovascular parent vessel occlusion without neurological deficit and in the second a spontaneous thrombosis of the aneurysm and its parent artery occurred associated with hydrocephalus and a favourable outcome.

CONCLUSION

Dissecting aneurysms are dynamic lesions with variable and unpredictable evolution and close follow-up and/or early treatment is warranted. Spontaneous arterial dissection is a rare, probably still under-recognized, cause of intracranial aneurysms that may be responsible for a significant number of aneurysms and spontaneous aneurysmal thromboses in children.

Isolated dissections and dissecting aneurysms of the posterior inferior cerebellar artery: topic and literature review

Isolated dissections of the posterior inferior cerebellar artery (PICA) are rare. Thus, no large series of cases have been reported in the literature. Due to limited knowledge regarding the natural history of these lesions and the lack of high-quality evidence supporting various treatment options, management is controversial and practice parameters are ill defined. In order to offer a comprehensive reference for the diagnosis and management of isolated PICA dissections, the authors reviewed the National Library of Medicine from 1966 to October 2001. Twenty-seven patients averaging 43.6 years of age and including 14 males and 13 females were reported. Subarachnoid hemorrhage occurred in 20 patients, and two died. Dissections were located in the proximal PICA in 22 patients and were three times more common on the left side (left:right=3:1). Six patients were managed conservatively, and four with endovascular techniques. Seventeen had open surgery: five underwent resection, two went through trapping, and two had proximal clipping. Wrapping with muscle was performed in two patients, encasement with Sundt clips in two, and four had occipital artery (OA)-PICA bypass surgery. A meticulous analysis of reported cases with regard to clinical and pathological features, management strategies, and outcomes is presented.