Remote cerebellar hemorrhage after spinal procedures (part 2): a systematic review.

A remote cerebellar hemorrhage (RCH) is a spontaneous bleeding in the posterior fossa, which can be rarely observed as a complication of spine surgery. As well as for RCH reported after supratentorial procedures, it shows a characteristic bleeding pattern defined "zebra sign". Nowadays, RCH pathophysiology still remains unknown. We performed a comprehensive review, collecting all cases of RCH after spine surgery reported in literature in order to identify the procedures most frequently associated with RCH and the possible risk factors. We assessed percentages of incidence and 95 % confidence interval of all demographic, neuroradiological, and clinical features. Univariate and multivariate analyses were used to evaluate their association with outcome. We included 44 articles reporting 57 patients with mean age of 57.6 ± 13.9 years and a male/female ratio of 23/34. A RCH was more frequently reported as a complication of decompressive procedures for spinal canal stenosis, particularly when associated with instrumented fusion, followed by spinal tumor debulking and disc herniation removal. In the majority of cases, RCH occurrence was characterized by progressive impairment of consciousness, whereas some patients complained non-specific symptoms. Coagulation disorders, hypertension, and placement of postoperative subfascial drainages were the most frequently reported risk factors. The occurrence of intraoperative dural lesions was described in about 93 % of patients. Zebra sign was the most common bleeding pattern (about 43 % of cases) followed by parenchymal hematoma (37.5 %) and mixed hemorrhage (about 20 %). Impairment of consciousness at clinical onset and intake of anticoagulants/antiplatelets appeared associated with poor outcome at univariate analysis. However, more than 75 % of patients showed a good outcome and a RCH often appeared as a benign and self-limiting condition, which usually did not require surgical treatment, but only prolonged clinical surveillance, unless of the occurrence of complications.