Dural sinus thrombosis after resection of vestibular schwannoma using suboccipital retrosigmoid approach-thrombosis classification and management proposal.

Dural sinus thrombosis is one of the complications after posterior fossa surgery. However, that topic is not described well with regard to vestibular schwannoma surgery using the unique suboccipital retrosigmoid approach. We analyzed retrospectively medical records and radiological investigations of 116 patients. The including criteria were histopathologically confirmed vestibular schwannoma operated on using the retrosigmoid approach, preoperative and postoperative contrast-enhanced MRI, and at least 1-year follow-up. The patient group included 36% males and 64% females. The average age was 47.3 ± 13.9 years. Sixty percent of the tumors were classified as T4b according to the Hannover scale and their mean volume was 13.73 ± 10.28 cm3. There were no signs of thrombosis preoperatively. Postoperative changes in the dural sinuses were found in 26 (22%) cases. In 7 (27%) cases, there was an external compression by the hemostatic agent, and in 19 (73%) cases, a thrombus was visualized in the sinus lumen. The size of the sinus, age, and the tumor size were not risk factors for thrombosis, whereas an intraoperative sinus injury was a statistically significant risk factor (p = 0.0012). All of the patients diagnosed with thrombosis were in good clinical condition in long-term follow-up, except one fatal case. Complete recanalization was observed in 58% of cases after 1-year follow-up. Postoperative changes in the dural venous sinuses are a frequent finding after vestibular schwannoma surgery using the suboccipital retrosigmoid approach. Intraoperative dural injury is a risk factor for thrombosis. Thrombosis in that group of patients is usually asymptomatic and does not influence the prognosis.