Therapeutic Catheter Microjet Distribution
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Solution Overview
Problem
Conventional spinal catheters face challenges in delivering therapeutic agents to the intrathecal space due to small injectate volumes and low CSF flow, leading to accumulation of agents near the catheter tip, increased risk of local toxicity, and poor rostrocaudal distribution, which can result in meningeal granuloma and other adverse effects.
Innovation Solution
A catheter system featuring an elongate tube with a pattern of small slits that remain closed until a pressure pulse opens them, emitting microjets of therapeutic agents along the catheter length, ensuring even distribution and reducing local toxicity by minimizing exposure to high concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional open port catheters are used for delivery, then the catheter structure is simple, but the therapeutic agent accumulates near the catheter tip causing local toxicity
Solution Approach 1:
The catheter divides the single large open port into multiple smaller ports distributed along the catheter length. This segmentation allows the therapeutic agent to be delivered to multiple locations simultaneously, preventing accumulation at a single site and reducing local toxicity while maintaining manufacturing feasibility.
Solution Approach 2:
Different ports are positioned at different locations along the catheter to create localized delivery zones. The proximal ports and distal ports deliver agent to different spinal regions, ensuring that no single location receives excessive concentrations that would cause toxicity.
2Quantity of substance
If small injectate volumes are used, then the pump reservoir volume is optimized, but the therapeutic agent does not distribute properly causing accumulation
Solution Approach 1:
Multiple ports distributed along the catheter enable a small total injectate volume to be divided and delivered to multiple locations simultaneously. This ensures adequate distribution reliability even when the total volume is limited by pump reservoir constraints.
Solution Approach 2:
The invention transitions from single-point delivery to distributed linear delivery along the catheter length. This dimensional change from a single location to multiple locations along the catheter allows small volumes to achieve broader distribution and reliable coverage.
3Productivity
If low delivery rates are used, then the implanted pump operates efficiently, but the injectate exits at low velocities causing tissue exposure to high concentrations
Solution Approach 1:
Multiple ports allow the total delivery rate to be divided into parallel flow paths. Even at low overall delivery rates, the agent is distributed across multiple exit points, reducing the concentration at any single tissue location and minimizing toxicity.
Solution Approach 2:
Multiple ports create multiple copies of the delivery function. Each port independently delivers agent to different locations, ensuring that low velocity exit does not result in high concentration exposure at any single site.
4Ease of manufacture
If open ports are used for delivery, then the catheter is easy to manufacture, but cellular debris accumulates within the catheter lumen during chronic implantation
Solution Approach 1:
The catheter employs a closed lumen structure with flexible thin film walls that contain the therapeutic agent during storage and implantation. This closed shell prevents cellular debris and fibroblasts from entering and accumulating within the lumen during chronic implantation, while maintaining manufacturing simplicity.
Solution Approach 2:
Multiple small ports provide sufficient total delivery area while maintaining a closed lumen system. The segmented port structure allows effective drug delivery without requiring large open ports that would be more susceptible to debris accumulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The microjet catheter system achieves widespread distribution of therapeutic agents over a longer rostrocaudal length, reducing the need for higher drug doses and minimizing local toxicity, while preventing debris accumulation, making it suitable for chronic use.
Implementation Method 1
configured to open in response to a pressure pulse in the lumen and emit a microjet of therapeutic agent from each slit
Implementation Method 2
emit a microjet of therapeutic agent from each slit in the pattern of slits
Data Source
AI summary
A therapeutic agent delivery catheter system includes an elongate tube defining a lumen therein formed from biocompatible material and sized to insert in a patient. The elongate tube has a length that extends to reach a treatment region of the patient. A pattern of slits forming microvalves penetrates an outer wall of the tube. The slits are small enough to remain closed to contain a solution of therapeutic agent, and are configured to open in response to a pressure pulse in the lumen and emit a microjet of therapeutic agent from each slit in the pattern of slits distributed along the rostro caudal extent of the implanted catheter.