Anchor Insertion Instrument for Lumbar Annular Defect Approximation
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Solution Overview
Problem
Conventional orthopaedic surgical procedures face challenges in effectively addressing annular defects during lumbar microdiscectomy, as they either risk reherniation or disc height collapse, and existing expandable implants do not provide a reliable solution for securing anatomical structures.
Innovation Solution
An insertion instrument is designed to eject and expand anchors with a substrate and actuation member, allowing for secure anchoring across anatomical defects by collapsing and expanding along specific directions, thereby approximating and stabilizing the defect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extensive debulking is performed to minimize reherniation risk, then reherniation risk is reduced, but disc height collapse risk increases
Solution Approach 1:
The annulus is divided into multiple segments using multiple anchors positioned at different locations. Each anchor independently secures a segment of the annulus, providing distributed support that prevents both reherniation and disc height collapse simultaneously.
Solution Approach 2:
The anchors are inserted and expanded before the surgical procedure is completed. This preliminary action stabilizes the annulus defect in advance, preventing reherniation during subsequent operations while maintaining disc height through the distributed anchor configuration.
2Reliability
If standard microdiscectomy technique is used, then radiculopathy is treated, but annular defect remains open increasing reherniation risk
Solution Approach 1:
The herniated nucleus pulposus is extracted and removed from the annulus, while the anchors remain to secure the annular defect. This separates the removal of the problematic material from the closure of the defect, achieving both radiculopathy treatment and defect closure.
Solution Approach 2:
The anchors serve as intermediary elements that bridge the gap between the removed herniated material and the remaining annulus. They provide structural support to close the defect while allowing the surgical procedure to be completed.
3Shape
If conventional expandable implants are used, then expansion is achieved, but reliable securing of anatomical structures is not provided
Solution Approach 1:
Each anchor is designed with localized expansion characteristics tailored to specific anatomical requirements. The anchors expand radially to engage with the annulus at specific locations, providing reliable securing while maintaining the expandable configuration for easy insertion.
Solution Approach 2:
The anchors are inserted in a compressed state within the cannula and then expand to their full size once positioned in the annulus. This nested configuration allows the anchors to be delivered through a small access hole while achieving reliable expansion and securing in the target location.
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 solution provides a stable anchoring mechanism that approximates anatomical defects, reducing the risk of reherniation and disc height collapse, while ensuring secure fixation of anatomical structures.
Implementation Method 1
When a tensile force is applied to the actuation member along a direction substantially along the direction of elongation, the anchor body collapses along the direction of elongation and expands along a second perpendicular with respect to the direction of elongation
Data Source
AI summary
An insertion instrument is configured to eject a pair of anchor bodies across an anatomical gap so as to approximate the gap. The insertion instrument can include a single cannula that retains the pair of anchor bodies in a stacked relationship, or a pair of adjacent cannulas that each retain respective anchor bodies. The insertion instrument can be actuated so as to eject the anchor bodies into respective target anatomical locations.