Usefulness of postoperative ventriculography and intracranial pressure monitoring following endoscopic third ventriculostomy.

Abstract

The authors sought to determine whether the insertion of an external ventricular drain (EVD) at the time of surgery to monitor intracranial pressure (ICP) and ventriculography done within the first day following an endoscopic third ventriculostomy (ETV) is of benefit in postoperative patient management. Following IRB approval, ETV procedures done by the senior author between January 1, 2007, and December 31, 2016, were reviewed. Included in a consecutive fashion were all patients who underwent an ETV with placement of an external ventricular drain (EVD) that was preceded preoperatively by an MRI or CT study and followed by a contrast CT ventriculogram within the first postoperative day. Identified were 72 patients who met the above criteria; however, technical ventriculography failure occurred in 4 (6%) and were eliminated from the analysis. Of the remaining 68 patients, contrasted CSF was seen in the basal cisterns/subarachnoid spaces (SAS) in 66 (97%) indicating a patent ETV and absent in 2 (3%) indicating a non-patent ETV. Of the 66 patients with a patent ETV, 34 (52%) patients were discharged on postoperative days 1 (8), 2 (13), and 3 (13) as their ICPs were not elevated and their clinical symptoms normal. EVDs placed at the time of the ETV recorded raised ICP > 20cm H2O in 17/68 (25%) patients for 1 or more days, all of whom had a patent ETV. Because of persistently elevated ICP requiring CSF drainage for control, 4 of these patients were shunted on postoperative days 5, 6, 6, and 10 and 3 with prolonged elevated ICP for 5, 6, and 11days postoperatively were not shunted as their ICP and symptoms progressively normalized. The remaining 17/68 (25%) patients did not have a postoperative ICP > 20cm H2O; 14 were discharged after resolution of symptoms and other clinical factors, 1 was shunted on postoperative day 3 due to persistent symptoms and a consistently large volume of CSF drainage, and 2 had a non-patent ETV with 1 undergoing shunt placement and the other discharged because of the absence of symptoms. The sensitivity of ventriculography was only 13%; however, the specificity was 98% and the accuracy 88%. After reviewing this series, the continued use of a postoperative EVD appears appropriate as the risk is low and it provides ventricular access to control ICP, thereby, improving patients' safety and reducing the need for CSF shunting on an urgent/emergent basis should the ETV prove to be unsuccessful. From our limited series, the usefulness of a 1-day postoperative ETV ventriculogram is less clear and would need confirmation with additional studies.