Flexible Cannula and Nitinol Needle for Subretinal Drug Delivery
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Solution Overview
Problem
Current methods for treating macular degeneration, particularly in accessing the subretinal space for localized delivery of therapeutic agents, are challenging due to the difficulty in reaching the macula at the back of the eye without causing trauma or inefficiency.
Innovation Solution
A system comprising a flexible cannula with a slidable needle, designed for subretinal administration from a suprachoroidal approach, which includes a cannula made of Polyether block amide (PEBA) for flexibility and a nitinol needle for precise delivery of therapeutic agents directly to the subretinal space, minimizing trauma and ensuring accurate placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid catheter or surgical tool is used to access the subretinal space, then the structural strength and stability are improved, but the ease of operation and ability to navigate the suprachoroidal space are worsened
Solution Approach 1:
The catheter is constructed with a flexible material that allows it to conform to and navigate the curved suprachoroidal space while maintaining sufficient structural integrity to deliver therapeutic agents. This flexibility enables the catheter to be inserted through the sclera and maneuvered along the choroid to reach the subretinal space without causing excessive trauma.
2Ease of operation
If a flexible cannula is used to navigate the suprachoroidal space, then the ease of operation is improved, but the manufacturing precision and control over needle placement are worsened
Solution Approach 1:
The needle is nested within the flexible catheter, allowing the catheter to be inserted and positioned first, followed by the deployment of the needle to the precise desired location. This nested configuration enables the flexible catheter to provide a stable track while the needle achieves precise placement through controlled extension.
3Measurement precision
If the needle is extended fully to reach the subretinal space, then the delivery precision is improved, but the risk of trauma to the retina and surrounding tissues is worsened
Solution Approach 1:
The flexible catheter is inserted and positioned in the suprachoroidal space before the needle is extended to the subretinal space. This preliminary positioning creates a stable pathway and allows for controlled, step-by-step advancement of the needle, reducing the risk of sudden tissue trauma while achieving precise therapeutic delivery.
4Measurement precision
If a complex surgical instrument is used to access the subretinal space, then the delivery precision is improved, but the device complexity and difficulty of operation are worsened
Solution Approach 1:
The catheter system is designed to perform multiple functions: navigating the suprachoroidal space, positioning at the target subretinal location, and delivering therapeutic agents. This multi-functional design eliminates the need for separate instruments for each step, reducing overall device complexity while maintaining delivery precision.
Data Source
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AI summary
An apparatus (10) for delivering therapeutic agent to an eye comprises a body (40), a cannula (20), a hollow needle (30), an actuation assembly (60), and a detection/visualization system. The cannula extends distally from the body and is sized and configured to be insertable between a choroid and a sclera of a patient's eye. The actuation assembly is operable to actuate the needle relative to the cannula to thereby drive a distal portion of the needle along an exit axis. The cannula may be inserted through a sclerotomy incision and advanced through the choroid to deliver the therapeutic agent adjacent to the potential space between the neurosensory retina and the retinal pigment epithelium layer. The detection/visualization system is operable to detect or visualize penetration of the choroid of a patient's eye and provide feedback to the operator and/or automatic control of the apparatus based on penetration of the choroid.