Intervertebral Disc Prosthesis with Shape Memory Spiral Frame
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Solution Overview
Problem
Existing osteoimplantable devices for repairing intervertebral discs are difficult to implant, require invasive procedures, and may not adapt to variations in the intervertebral space due to degenerative changes, and often protrude towards nerve spaces or weaken over time.
Innovation Solution
A compact osteoimplantable device with an anchoring body and a prosthesis that can be implanted minimally invasively, featuring a flexible membrane with shape memory properties and a spiral frame that expands to occlude the nucleus pulposus, allowing it to adapt to varying disc spaces and maintain position without protruding into nerve spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a band with strips is used to repair the disc rupture, then the nucleus leakage can be retained, but the implantation process becomes complicated and requires skilled surgery with multiple perforations
Solution Approach 1:
The device is divided into a band component and a separate anchoring system. The band remains simple while the anchoring function is segmented into distinct elements that attach to vertebrae, separating the retention function from the anchoring function to simplify overall implantation.
Solution Approach 2:
The anchoring elements are designed to be pre-positioned or pre-attached to the band, allowing the perforations and anchoring to be performed before the band is tensioned and tied, simplifying the sequential steps required during surgery.
2Reliability
If a mesh patch is used to cover the herniated disc, then the rupture can be sealed, but the mesh requires difficult positioning and anchoring while maintaining tension
Solution Approach 1:
The band is designed as a flexible thin film structure that can conform to the disc geometry and be easily positioned over the rupture site. Its flexibility allows it to be maneuvered into place and maintain sealing effectiveness while adapting to the natural curvature of the disc.
Solution Approach 2:
The band system incorporates dynamic tensioning capabilities where the band can be adjusted and secured at optimal tension levels after positioning, allowing the surgeon to achieve proper sealing without the difficulty of maintaining tension during the entire anchoring process.
3Reliability
If suture threads with anchors are used to repair the damaged zone, then the disc can be sutured closed, but the device lacks rigidity and is difficult to insert correctly
Solution Approach 1:
The band is designed with a curved or arched configuration that naturally conforms to the cylindrical geometry of the intervertebral disc. This curved structure provides inherent rigidity and structural integrity while maintaining the ability to be inserted through a minimally invasive approach, eliminating the need for complex insertion maneuvers required by rigid suture systems.
4Reliability
If an expandable plug is used to fill the damaged zone, then the nucleus can be retained, but the device requires large opening for implantation and cannot be done minimally invasively
Solution Approach 1:
The band system can be nested within or alongside the expandable plug device during minimally invasive delivery. The band is positioned first to provide the sealing function, and the plug is then deployed within the disc space, allowing both retention mechanisms to work together through a single small incision without requiring large openings.
5Reliability
If anchors are used to fix the device to vertebrae, then the device can be secured, but the device may protrude towards the nerve space
Solution Approach 1:
The anchoring elements are designed with localized engagement features that attach to specific regions of the vertebrae away from the neural foramina. The band itself is configured to distribute forces locally across the disc surface, preventing concentration of stress that could cause protrusion towards nerve spaces while maintaining secure fixation.
6Adaptability or versatility
If the intervertebral space reduces due to degenerative changes, then the device must adapt to varying disc spaces, but fixed-size devices cannot accommodate these variations
Solution Approach 1:
The band incorporates dynamic adjustment mechanisms that allow it to be tensioned and secured at different lengths and configurations. This enables the same band design to effectively span varying disc spaces whether the disc is healthy or has undergone degenerative changes, maintaining retention effectiveness across different anatomical conditions.
Solution Approach 2:
The device allows for parameter adjustments including band tension, anchoring depth, and element positioning that can be modified during implantation to match the specific intervertebral space dimensions. This adaptability ensures reliable nucleus retention whether the disc space is large or reduced due to degeneration.
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
Enables minimally invasive implantation, adapts to changes in intervertebral space, and maintains effective occlusion of the nucleus pulposus, reducing the risk of nerve contact and device failure due to space variations.
Implementation Method 1
featuring a flexible membrane with shape memory properties and a spiral frame that expands
Data Source
AI summary
A device (1, 100) for repairing an intervertebral disc comprising an anchoring body (2, 102), suitable for being advanced into and secured in one of the vertebrae adjacent the intervertebral disc; and a prosthesis (3, 103, 203, 303) attachable in a secure coupling position to the anchoring body (2, 102) and adapted for retaining or replacing the nucleus pulposus in an interior space of an outer annulus of the intervertebral disc, the anchoring body supporting and arranging in the cited coupling position the prosthesis such that the prosthesis is oriented to in a direction toward and through a hole in the outer annulus, the prosthesis comprising at least one active portion (4) adapted to assume and maintain a first placement shape (A) suitable for permitting the active portion to be inserted into and through the hole in the outer annulus during a placement thereof into the interior space of the outer annulus, and at least a second operative shape (B) suitable for at least partially occluding the hole in the outer annulus and/or replacing at least a portion of the nucleus pulposus upon the active portion assuming a placement position in the interior space of the outer annulus.