Venous sinus thrombosis associated posterior cranial fossa surgery. A systematic review and meta-analysis of natural history, risk factors, treatment and outcome.

BACKGROUND Venous sinus thromboses (VST) are rare complications of neurosurgical procedures in proximity of the dural sinuses. Surgery of posterior cranial fossa (PCF) and particularly of cerebello-pontine angle (CPA) show increased risk of VST. VST management is challenging as anticoagulant therapy must be balanced with the risk of post-operative bleeding. We performed a systematic review and meta-analysis to summarize the most important neuroradiological and clinical aspects of VST after PCF/CPA surgery. METHODS We performed a comprehensive literature search to identify manuscripts reporting data on VST after PCF/CPA surgery. We selected only comparative studies providing adequate neuroimaging assessing VST and a control group. RESULTS We included 13 papers reporting 1855 patients. VST occurred in 251/1855 cases (estimated incidence: 17.3%; 95%CI:12.4%-22.2%). Only presigmoid approach (OR 2.505; 95%CI:1.161-5.404; p=0.019) and intraoperative sinus injury (OR 8.95; 95%CI:3.43-23.34; p<.001) showed a significant association with VST. VST-related symptoms were reported in 12/251 VST patients (pooled incidence: 3.1%; 95%CI:1%-5.2%). In particular, we found a significant increased OR of CSF leak (OR 3.197; 95%CI:1.899-5.382; p<.001) and of CSF dynamic alterations in general (OR 3.625; 95%CI:2.370-5.543; p<.001). Indications for VST treatment were heterogeneous: 58/251 patients underwent antithrombotics, with 6 treatment-related bleedings. Recanalization overall occurred in 56.4% (CI95%:40.6%-72.2%) with no significant difference between treated and untreated patients. Untreated patients however had a favorable outcome. CONCLUSION VST is a relatively frequent complication after PCF/CPA surgery and presigmoid approach and intraoperative sinus injury represent the most significant risk factors. However, clinical course is generally benign, with no advantage of antithrombotic therapy.