Expandable Tip Cannula for Disc Augmentation Leakage Control
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Solution Overview
Problem
Current methods for determining the volume of intervertebral disc augmentation material and delivering it accurately face challenges such as leakage due to inadequate fit between rigid cannulas and varying annular wall defects, leading to improper disc replacement and potential re-herniation or further spinal issues.
Innovation Solution
A cannulated delivery tube with an expandable or inflatable tip and an anti-backflow check valve is used to seal the annular defect, allowing for precise volume determination and leak-proof delivery of replacement material by injecting a known amount of volumetric material and aspirating it to match the removed nucleus pulposus volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid injection cannula is used to deliver nucleus replacement material, then the delivery structure is simple and strong, but the fit with varying annular wall defects is inadequate causing material leakage
Solution Approach 1:
The cannula tip is designed to be expandable or conformable, allowing it to dynamically adapt its shape and size to match the specific geometry of the annular wall defect. This dynamic adjustment capability enables the rigid cannula body to maintain structural simplicity while the tip provides a reliable seal against varying defect configurations, preventing material leakage.
Solution Approach 2:
The cannula incorporates a flexible or conformable tip section that can deform to conform to the irregular surfaces of the annular wall defect. This flexible interface between the rigid cannula and the defect wall creates an effective seal without requiring complex overall cannula structure, resolving the contradiction between simplicity and sealing reliability.
2Measurement precision
If excess nucleus replacement material is injected to ensure adequate disc replacement, then the risk of improper functional balance increases, but material leakage occurs when accurate volume control is attempted
Solution Approach 1:
The system employs feedback through the use of an imaging balloon filled with contrast medium and fluoroscopic imaging to visually confirm proper material delivery and disc space filling. This feedback mechanism allows the surgeon to monitor the injection process in real-time, ensuring accurate volume delivery without leakage while maintaining proper functional balance, thus resolving the contradiction between measurement precision and delivery reliability.
Solution Approach 2:
The cannula is pre-sealed to the annular wall defect before material injection, creating a closed system that prevents leakage during delivery. This preliminary sealing action ensures that subsequent volume measurements and material injections occur in a controlled environment, eliminating the leakage problem that plagues open injection systems while maintaining accurate volume control.
3Adaptability or versatility
If the annular wall defect is not properly sealed during material injection, then material leakage occurs, but achieving a seal requires a custom-fitted device for each defect size
Solution Approach 1:
The cannula tip is designed with expandable or conformable characteristics that allow it to adapt to different annular wall defect sizes and shapes. This dynamic adaptability enables a single cannula design to seal effectively against varying defect configurations without requiring custom-fitted devices for each specific defect, thus resolving the contradiction between adaptability and device complexity.
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
This method ensures accurate determination of the volume of nucleus pulposus material removed and prevents leakage during injection, maintaining proper disc height and reducing the risk of re-herniation or additional pain by ensuring the correct amount of replacement material is delivered without leakage.
Implementation Method 1
A cannulated delivery tube with an expandable or inflatable tip and an anti-backflow check valve is used to seal the annular defect
Implementation Method 2
A cannulated delivery tube with an expandable or inflatable tip and an anti-backflow check valve is used to seal the annular defect
Data Source
AI summary
The invention provides a device and technique to seal an annular defect of an intervertebral disc, determine the in-situ volume of nucleus pulposus material removed, for example from a discectomy of a herniated disc, and facilitate injection of nuclear replacement material.