Introduction: Multiple experimental therapies have employed stereotactic intracerebral transplantation of stem cells. However, stereotactic injection techniques have received little critical attention, and use of intraoperative CT guidance and accuracy of implantation has not been reported. This is critical for sophisticated stem cell applications which target highly eloquent small nuclei of the brain, for example.
Methods: Ten patients with history of ischemic stroke underwent CT-guided stem cell transplantation, as part of an ongoing clinical trial. Cells were delivered along 3 tracts adjacent to the stroke bed. Intraoperative air deposits and postoperative T2-weighted MRI signal were mapped in relation to surgical targets using Euclidian distances.
Results: The deepest air deposit was found 4.5 +/- 1.0 mm (mean +/- 2 SEM) from target. The apex of the T2-hyperintense tract was found 2.8 +/- 0.8 mm from target. On average, air pockets were found anterior (1.2 +/- 1.1 mm, p=0.04) and superior (2.4 +/- 1.0 mm, p<0.001) to the target; no directional bias was noted for the apex of the T2-hyperintense tract. Location and distribution of air deposits was variable, and was affected by relationship of cannula trajectory to stroke cavity.
Conclusions: Precise stereotactic cell transplantation is a little-studied technical challenge. Reflux of cell suspension and air, and the extracellular space of the target structure, affect accuracy and assessment of delivery. However, intraoperative CT allows confirmation of delivery, assessment of the boundaries of delivery, and potential correction of trajectories.
Patient Care: This research will guide use of intraoperative CT for stereotactic cell transplantation and inform development of techniques to optimize cell delivery.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe technical challenges associated with stereotactic cell transplantation, and 2) Discuss the role of intraoperative CT in stereotactic cell transplantation.