Dissection of the Posteroinferior Cerebellar Artery: Clinical Characteristics and Long-Term Follow-Up in Five Cases

<i>Background and Purpose:</i> 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. <i>Methods and Results:</i> 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. <i>Conclusion:</i> 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.