Cannulated Bone Screw for Controlled Intervertebral Dosing
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Solution Overview
Problem
Current methods for percutaneous drug delivery into the intervertebral disc often result in material leakage and weakening of the annulus, leading to potential rupture, especially with repeated dosing requiring multiple needle insertions.
Innovation Solution
A cannulated bone screw with a screw shaft, inlet, and outlet ports, and a plunger-controlled valve system for controlled fluid flow, allowing for repeated dosing without annulus perforation, combined with a temporary encasement for tissue penetration and bioresorbable components for minimal foreign body presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If percutaneous needle insertion is used for drug delivery into the intervertebral disc, then therapy delivery is achieved, but material leaks out of the disc and the annulus is weakened making it susceptible to rupture
Solution Approach 1:
The patent introduces an intervertebral dosing device as an intermediary system between the needle and the disc. The device includes a dosing needle that inserts through the annulus, a dosing chamber that receives therapeutic material, and a dosing region within the disc. This intermediary structure allows controlled delivery of therapy while minimizing direct needle contact with the disc interior, thereby reducing material leakage and annulus weakening.
Solution Approach 2:
The dosing device is segmented into distinct functional components: a needle portion for annulus penetration, a dosing chamber for material storage, and a dosing region for therapy delivery. This segmentation allows each component to be optimized for its specific function - the needle for minimal insertion trauma, the chamber for controlled material release, and the dosing region for targeted therapy delivery without affecting the entire annulus structure.
2Duration of action of moving object
If multiple needle insertions are performed for repeated dosing, then repeated therapy delivery is achieved, but the annulus progressively weakens increasing rupture risk
Solution Approach 1:
The dosing device is inserted and positioned within the intervertebral disc during an initial procedure. Once in place, the device remains positioned and can be used for multiple dosing sessions without requiring repeated needle insertions through the annulus. The preliminary insertion establishes a stable access pathway that can be utilized repeatedly for therapy delivery.
Solution Approach 2:
The permanently positioned dosing device serves as an intermediary structure that eliminates the need for repeated needle insertions. The device includes a dosing chamber that can be refilled and a dosing region that delivers therapy through the intervertebral disc. This intermediary system allows multiple dosing sessions to occur through the same initial insertion site, preventing progressive annulus weakening that would result from multiple separate needle insertions.
3Strength
If a single percutaneous insertion is used for repeated dosing, then annulus strength is preserved, but a device capable of repeated dosing without perforation is needed
Solution Approach 1:
The dosing device employs a nested structure where a dosing chamber is positioned within or adjacent to the needle shaft, and the dosing region is positioned within the intervertebral disc. The therapeutic material is contained within the dosing chamber, which can be refilled through the needle. This nested arrangement allows the complex functionality of repeated dosing to be achieved within a compact structure that requires only a single initial insertion, preserving annulus strength while providing the needed device complexity for controlled, repeated therapy delivery.
Data Source
AI summary
Some embodiments of the invention include a cannulated bone screw including a screw shaft with screw thread, a proximal end, a distal end, and a channel extending through the screw shaft. Some embodiments include an inlet port coupled to the channel and extending through the distal end, and an outlet port coupled to the channel by a curved or angled channel region. In some embodiments, the outlet port extends through the screw shaft and exits a side that is substantially parallel to the shaft longitudinal axis. In some embodiments, the cannulated bone screw can form part of a therapy delivery device. In some embodiments, the outlet port extends through a portion of the screw shaft and exits at the distal end. In some embodiments, the valve includes a plunger with a plunger rod within the screw shaft, and a valve seat for control of fluid flow out of the screw.