A dissecting aneurysm of the posterior inferior cerebellar artery. A case report

Overlapping Pure LIVS Jr. Stents for Isolated Ruptured Dissecting Aneurysm of the Proximal Posterior Inferior Cerebellar Artery

We report our experience in treating a ruptured dissecting posterior inferior cerebellar artery (PICA) aneurysm. To our knowledge, this is the first reported case of overlapping stenting without coils for a ruptured dissecting aneurysm of the proximal PICA. A 66-year-old male patient presented with sudden altered mental state and a subarachnoid hemorrhage (SAH). The cerebral angiography revealed a long segmental dissecting aneurysm on proximal PICA. Overlapping stents were deployed to the dissecting site, and angiogram showed intact distal PICA flow and decreased contrast staining in the dissecting site. Successful flow diversion was achieved with stents. Procedure-associated complications did not occur. The patient’s postoperative course was uneventful. In follow-up cerebral angiography, dissecting aneurysm achieved complete remodeling. The decision that led to the choice of treatment is discussed.

Post-traumatic intracranial pseudo-aneurysms of posterior circulation: a comprehensive review of an under-diagnosed and rare entity

Traumatic aneurysms are rare and the total number of cases involving the posterior circulation (TIPC) is even smaller. Traumatic brain injury (TBI) may be responsible not only of rupture in brain aneurysm (BrA) pre-existing to trauma, but it has been identified also as a possible pathogenetic cause of TIPC formation in patients not affected by intracranial vascular lesions. A complete literature review was performed of all reported cases regarding rupture of BrA with SAH resulting from TIPC not previously identified at the first radiological screening. A representative case of a left posterior inferior cerebellar artery (PICA) pseudo-aneurysm caused by left vertebral artery’s dissection is reported. We show a unique complete collection of all 34 cases. Despite their rarity, TIPCs are associated with a significant morbidity and mortality rate, as high as 40–60%. Of the 22 patients with good neurological status (64.7%), we did not notice a significant correlation with regard to the location of the aneurysm, type of treatment, or clinical onset. Early recognition of a pseudo-aneurysm and adequate treatment seem to be the most important prognostic factor for these patients. Despite their rarity, TIPCs are associated with a significant morbidity and mortality rate. A TIPC should be suspected in case of delayed deterioration in head‐injured patient and should be investigated with angiography. Conservative management is worsened by poor prognosis and the goal of treatment is to exclude the aneurysm from circulation with surgical or endovascular methods as soon as possible.

Dissecting Fusiform PICA Aneurysm Repair With Trapping and an Unconventional End-to-Side Reanastomosis: 2-Dimensional Operative Video

Dissecting fusiform posterior inferior cerebellar artery (PICA) aneurysms are rare and challenging.1,2 One common treatment is occlusion of the aneurysm and parent artery via an endovascular approach without revascularization.3 Revascularization of the artery requires an open microsurgical bypass or endovascular placement of a newer-generation flow diverter.4 We present an end-to-side reanastomosis of the PICA for treatment of a dissecting fusiform left PICA aneurysm with anatomy deemed unfavorable for endovascular treatment in a 62-yr-old man with subarachnoid hemorrhage. After discussions regarding risks, benefits, and alternatives to the procedure, the family consented to surgical treatment.  A far-lateral craniotomy was performed, with partial condylectomy to widen the exposure. The cisterna magna was opened, and the dentate ligament was cut to visualize the vertebral artery. The PICA was identified and traced distally to the aneurysmal segment, which was circumferentially diseased. Perforators were noted immediately distal to the aneurysm. The aneurysm was then trapped, and the afferent artery was transected and brought to the sidewall of the distal artery. The recipient site was trapped with temporary clips, and a linear arteriotomy was made. An end-to-side reanastomosis was performed, temporary clips were removed, and hemostasis was achieved. Postoperative angiography confirmed bypass patency and preservation of the PICA perforators.  Conventional reanastomosis of the parent artery after aneurysm excision is achieved by end-to-end reanastomosis. In contrast, we performed an unconventional end-to-side reanastomosis to revascularize the PICA while leaving the efferent artery in situ to protect its medullary perforators. This bypass is an example of a fourth-generation bypass.5,6 Used with permission from the Barrow Neurological Institute, Phoenix, Arizona.

Treatment Strategy for Isolated Posterior Inferior Cerebellar Artery Dissection

OBJECTIVE

Isolated dissections that develop on the posterior inferior cerebellar artery (PICA) require intensive treatment because of their potential fatality. However, because of the rarity of these dissections, the optimal treatment has not yet been established.

METHODS

We retrospectively reviewed the clinical records of all patients who underwent any PICA dissection treatment in our institute over the last 4 years. Ten patients were enrolled, including 7 patients with subarachnoid hemorrhage (SAH) and 3 with PICA territory infarction. Dissection was seen at the proximal portion in 8 patients, whereas the remaining 2 patients showed distal PICA dissecting aneurysms.

RESULTS

Among the 7 patients with hemorrhage, 5 were actively treated (trapping and bypass, 2 patients; surgical clipping, 1 patient; coil embolization, 2 patients). Conservative management was performed in the other 2 patients. Among the 3 patients with infarction, 2 received conservative treatment. Endovascular treatment was performed in 1 patient, who showed rapid progression, aneurysm formation, and conversion to massive SAH within 10 days after the initial attack. Although 7 patients showed relatively good outcomes (modified Rankin Scale score, ≤2) after 30 days of follow-up, 1 patient had a final modified Rankin Scale score of 3. In addition, the other 2 patients (1 in each group) died as a result of major SAH.

CONCLUSIONS

Given the dynamic clinical course and potential fatality of PICA dissection, meticulous evaluation, intensive treatment with a diverse range of modalities, and proper follow-up are required for patients with PICA dissection to achieve favorable outcomes.

In Situ Intersegmental Anastomosis within a Single Artery for Treatment of an Aneurysm at the Posterior Inferior Cerebellar Artery: Closing Omega Bypass

A 74-year-old patient was diagnosed with a subarachnoid hemorrhage suspected from a dissecting aneurysm located at the lateral medullary segment of the posterior inferior cerebellar artery (PICA). Because perforators to the medulla arose both proximal and distal to the dissecting segment, revascularization for distal flow was essential. However, several previously reported methods for anastomosis, such as an occipital artery-PICA bypass or resection with PICA end-to-end anastomosis could not be used. Ultimately, we performed an in situ side-to-side anastomosis of the proximal loop of the PICA with distal caudal loops within a single artery, as a "closing omega," followed by trapping of the dissected segment. The aneurysm was obliterated successfully, with intact patency of the revascularized PICA.

Subarachnoid hemorrhage then thrombosis of posterior inferior cerebellar artery dissection: is early surgical exploration warranted?

The natural history of spontaneous cerebral artery dissection and thrombosis remains uncertain. Concurrent subarachnoid hemorrhage further complicates the therapeutic approach. Thus the best strategy for managing patients with acute vessel thrombosis in the setting of subarachnoid hemorrhage is unclear. Here we present a case of spontaneous posterior inferior cerebellar artery dissection presenting with subarachnoid hemorrhage and acute thrombosis. Although the patient was initially managed conservatively, angiographic follow-up demonstrated recanalization of the diseased vessel, necessitating definitive treatment. Thus we propose that angiographic follow-up is necessary in the management of patients with subarachnoid hemorrhage in association with apparent vessel thrombosis.

Subarachnoid hemorrhage then thrombosis of posterior inferior cerebellar artery dissection: is early surgical exploration warranted?

The natural history of spontaneous cerebral artery dissection and thrombosis remains uncertain. Concurrent subarachnoid hemorrhage further complicates the therapeutic approach. Thus the best strategy for managing patients with acute vessel thrombosis in the setting of subarachnoid hemorrhage is unclear. Here we present a case of spontaneous posterior inferior cerebellar artery dissection presenting with subarachnoid hemorrhage and acute thrombosis. Although the patient was initially managed conservatively, angiographic follow-up demonstrated recanalization of the diseased vessel, necessitating definitive treatment. Thus we propose that angiographic follow-up is necessary in the management of patients with subarachnoid hemorrhage in association with apparent vessel thrombosis.

Dissection of the posteroinferior cerebellar artery: clinical characteristics and long-term follow-up in five cases

BACKGROUND AND PURPOSE

Spontaneous isolated posteroinferior cerebellar artery (PICA) dissection is very rare. The aim of the study was to investigate the clinical manifestations, the neuroradiological aspects and the treatment of 5 cases collected in 5 years.

METHODS AND RESULTS

From 1999 to 2003, five patients (40-71 years old) were hospitalized for PICA dissection. Two patients presented symptoms after cervical manipulation. No predisposing factor or traumatic cause was described in the other cases. The diagnosis was carried out by cerebral angiography in all the cases: in 4, angiography showed focal stenosis with saccular or fusiform dilatation of the artery at the site of the dissection; in 1 a double lumen aspect was described. One patient presented ischemic manifestations; he was treated with heparin. The others presented subarachnoid hemorrhage (SAH) and were treated by embolization (endovascular sacrifice of the PICA). No ischemic complication and no rebleeding were observed after sacrifice of the PICA. Three patients presented acute hydrocephalus and were treated with surgical derivation. The angiographic and clinical follow-up lasted more than 3 years. We assessed the long-term results with the Glasgow Outcome Score and the modified Rankin Score. A good recovery was achieved for 4 patients (modified Rankin Score 0); one patient who presented SAH and who was in bad clinical state on admission had a Glasgow Outcome Score of 3 and a modified Rankin Score of 4 three years later.

CONCLUSION

Clinical course and prognosis are variable in PICA dissections. The treatment depends on the existence of a hemorrhagic event. In the group of patients presenting SAH, endovascular treatment was safe and effective. The long-term clinical results depend mainly on the clinical status on admission.

Endovascular treatment of isolated dissecting aneurysm of the posterior inferior cerebellar artery

BACKGROUND AND PURPOSE

Isolated dissecting aneurysms of the posterior inferior cerebellar artery (PICA) carry a high risk of rebleeding with an associated increased mortality rate. Although rare, they present a therapeutic challenge. Surgical treatment carries a significant risk of neurologic complications, predominantly lower cranial nerve deficits because of the close relationship of the aneurysm with the brain stem and cranial nerves. The purpose of this article is to show that endovascular treatment of dissecting aneurysms of the PICA can be effective and can allow the patient to avoid the complications associated with surgery.

METHODS

Six patients (age range, 28-70 years) with dissecting aneurysms of the PICA were treated at our center by endovascular occlusion with Guglielmi detachable coils or glue and followed for up to 30 months. Inclusion of patients in the study was based on careful angiographic assessment of the vascular anatomy and collateral supply of the posterior fossa. When on the basis of the anatomy, potential lack of sufficient collaterals was suggested, a test occlusion was performed to determine the feasibility of an endovascular approach. Four additional cases, which have been described in the literature, were included in the analysis of results.

RESULTS

In all patients, the aneurysm was successfully occluded with no apparent procedure-related complications. Follow-up studies showed stable and complete occlusion of the aneurysm in all patients with no long-term neurologic deficits.

CONCLUSIONS

Endovascular treatment by aneurysm and parent artery occlusion is a relatively safe and reliable alternative to surgery for isolated dissecting aneurysms of the PICA.