Retrograde third ventriculocisternostomy from the posterior fossa

Background: Postoperative hydrocephalus is common in patients after resection of a posterior fossa tumor, with as many as 25% of patients requiring permanent cerebrospinal fluid diversion in the form of ventricular shunting or ventriculocisternostomy in some series. Prophylactic ventriculocisternostomy has been described with success in this patient population to prevent postoperative hydrocephalus. Objective: To define the technique of microsurgical retrograde third ventriculostomy from the posterior fossa. Methods: The operative technique is described and a single patient with 4-year follow-up is reported. Results: We describe the case of a 32-year-old woman who presented with a large cerebellopontine angle epidermoid tumor. She underwent a simultaneous lesion resection and third ventriculocisternostomy by accessing the interpeduncular cistern via a suboccipital posterior fossa approach and then making an incision through the tuber cinereum to access the third ventricle under direct vision. Conclusion: Retrograde third ventriculostomy may be useful in the surgical treatment of patients already undergoing operations for large posterior fossa lesions who have a high likelihood of requiring permanent cerebrospinal fluid diversion and in whom exposure of the interpeduncular cistern is available.