Posterior inferior cerebellar artery dissecting aneurysm case reports

Shin et al. from the Department of Neurosurgery, Inje University, Ilsan Paik Hospital, Neuroscience & Radiosurgery Hybrid Neurosurgery Research Center, Goyang, Korea and Department of Neurosurgery, Uijeongbu Eulji Medical Center, Eulji University College of Medicine, Uijeongbu, Korea introduced a case of ruptured dissecting aneurysm located at the proximal PICA treated with telescoping stents for flow diversion and dissection healing. A 49 years old female visited to the emergency room for ruptured dissecting aneurysm at right proximal PICA. Telescoping stent was deployed along the right vertebral artery to PICA covering the dissecting aneurysm bleb using two Low-profile Visualized Intraluminal Support Jr (LVIS Jr) stents. Three months follow up angiography revealed a disappearance of aneurysm bleb and healing of dissection by parent artery remodeling. Telescoping stent with LVIS Jr may be an effective treatment for dissecting aneurysm with small diameter (<2 mm) parent artery. Convenient navigation and targeted telescoping stent for minimizing metal coverage at perforating arteries are an advantage for this method ¹⁾.

A 29-year-old woman was admitted complaining of thunderclap headache, nausea, and vomiting for 3 hours. Head computed tomography and digital subtraction angiography (DSA) revealed subarachnoid hemorrhage and a dissecting aneurysm located at the tonsillomedullary segment of PICA. The parent artery distal to the aneurysm had no collateral circulation from the adjacent arteries. Selective endovascular coiling of the aneurysm with preservation of the parent artery was adopted for treatment. The patient experienced an uneventful postprocedural recovery. To our surprise, follow-up DSA 6 months later revealed complete occlusion of the aneurysm and the parent artery at the site of aneurysm formation. A rare anastomosis between the distal PICA and PMA was established.

A report about this rare condition suggested that after occlusion of the PICA trunk, the distal PICA can form collateral circulation with the PMA. A potential collateral circulation may be present in advance between the PICA and PMA. When ischemia occurs in the distal PICA, this collateral circulation may open and could be reconstructed and enlarged to provide blood supply ²⁾.

Fransen and De Tribolet published the tenth case ³⁾

Three cases of posterior inferior cerebellar artery dissecting aneurysm. A literature search revealed only three previous cases. Analysis of these six cases showed a unique clinical picture. Three patients developed subarachnoid hemorrhage, and the other three had ischemia. All patients complained of occipital headache or neck pain, regardless of the initial symptoms. Heralding episodes were recorded in four cases. Angiography showed a characteristic fusiform dilatation of the PICA and a narrowing proximal to and distal to the lesion. Various surgical treatments were performed in five cases. Intraoperative observation showed a sausage-like swelling of the PICA or one of its branches with various discoloration depending on the age of the intramural clot. The outcomes were favorable ⁴⁾.