Introduction: Ommaya reservoirs are intraventricular catheters attached to a port-system that may be placed for the administration of intrathecal chemotherapy. The surgical complication rate associated with the placement of these devices has been previously described; however, an appropriate analysis and risk factor assessment has been limited by sample size. Further, no analysis has identified what risk factors, such as coagulopathies in cancer patients, are involved in the placement of these devices. Additionally, stereotactic navigation is increasingly utilized and may decrease complications and improve device placement.
Methods: We reviewed all Ommaya operations at our institution between June 1993 and January 2010 (n=835). Primary cancer diagnosis, the extent of intracranial disease, and prior neurosurgical operations were tabulated. Pre-operative lymphocyte and platelet counts, use of stereotactic navigation and other operative modalities were documented. Complications, defined as neurological and regional, or systemic, were assessed at 48 hours and at 30 days.
Results: Our analysis demonstrates a 10% incidence of complications (7% neurological/regional) at 48 hours. At 30 days, complications occurred in 36% (22% neurological/regional). Altered mental status was the most common complication at 48 hours and 30 days (2% and 5%, respectively). There was no significant reduction in complications associated with the use of stereotactic navigation at 48 hours and 30 days. However, stereotactic navigation allowed a significantly higher degree of precision (90%) in achieving the intended location (compared to 79%; p<0.05). An increased risk of complications at 30 days occurred for patients with a platelet count below 75,000 (x 10^9/L), a lymphocyte count below 800 cells/µL, and a diagnosis of leptomeningeal disease.
Conclusions: These findings involve the largest analysis to date of Ommaya catheter placements. These findings support the recommendation to transfuse platelets to a level above 75,000 (x 109/L) to reduce complications and the use of stereotactic navigation to significantly improve precision during Ommaya catheter placement.
Patient Care: An estimated 20,000 Ommaya reservoirs are now placed every year in the United States for leptomeningeal disease alone. Our research demonstrates a significant increase in precision of Ommaya reservoir placement with the use of stereotactic navigation and identifies a platelet threshold below which patients should receive transfusions prior to surgery to reduce complications. There are no guidelines as to the best techniques to employ during these surgeries, no assessment of the risk factors for complications, and no guidelines for pre-operative management - our research identifies and addresses each of these issues, which together address a significant gap in evidence-based neurosurgical practice.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Demonstrate an understanding of the risk factors and complications associated with Ommaya reservoir placement, 2) Identify the role of stereotactic navigation in the placement of Ommaya reservoirs, 3) Discuss the pre-operative recommendations that may minimize risk at 48 hours and 30 days following Ommaya reservoir placement.