The Relation between Catheter Occlusion and Backflow during Intraparenchymal Cerebral Infusions

Area of Science:

• Neurosurgery
• Biomedical Engineering
• Drug Delivery Systems

Background:

• Convection-enhanced delivery (CED) is crucial for targeted drug delivery to the brain.
• Infusate distribution in CED can be compromised by catheter shaft backflow.
• Catheter design and insertion techniques significantly impact CED efficacy.

Purpose of the Study:

• To investigate tissue coring and catheter lumen occlusion during open end-port catheter insertion.
• To determine the relationship between intracatheter pressure and infusate backflow.
• To assess if catheter occlusion exacerbates backflow during CED.

Main Methods:

• Ex vivo assessment of tissue coring and pressure dynamics using monkey brains.
• In vivo infusions into monkey putamen with and without a stylet during insertion.
• In vivo evaluation of flow during insertion in pig thalamus.
• Continuous MRI and line pressure monitoring during infusions.

Main Results:

• Open end-port catheter insertion consistently resulted in tissue coring, temporarily plugging the catheter tip and increasing pressure.
• Catheter insertion with a stylet prevented tissue coring but did not eliminate backflow.
• Infusing during insertion did not prevent coring and did not affect backflow.
• Backflow was not completely prevented by any tested insertion method.

Conclusions:

• Open end-port catheters are prone to occlusion during insertion due to tissue coring.
• Utilizing a stylet during insertion effectively prevents catheter coring.
• Neither stylet use nor infusion during insertion completely prevents infusate backflow in CED.