Rotatable PLIF Implant with Chamfered Faces for Spinal Distraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current posterior lumbar interbody fusion (PLIF) implants face challenges such as damage to vertebral bodies during insertion due to high insertion forces, deformation or breakage of implants, and inadequate distraction between vertebrae, along with a need for improved manufacturing and non-invasive data encoding for implanted devices.
Innovation Solution
A rotatable PLIF implant with parallel sidewalls, chamfered faces, and undulating surfaces for bone integration, manufactured using additive manufacturing or titanium, featuring a bifurcated insertion tool to reduce insertion force and enable structural encoding for identification post-implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high insertion force is applied to insert the PLIF implant, then the implant can be inserted into the disc space, but the vertebral bodies are damaged
Solution Approach 1:
The PLIF implant incorporates rounded edges along the perimeter of the superior and inferior faces, which distribute the insertion force more evenly across the vertebral endplates. This curvature design prevents stress concentration that would otherwise cause damage to the vertebral bodies during insertion.
Solution Approach 2:
The implant geometry is modified by adding chamfers to the superior and inferior faces, which change the insertion mechanics. The chamfered surfaces allow the implant to be seated at an oblique angle, distributing the insertion force over a larger area and reducing peak stresses on the vertebral bodies.
2Ease of operation
If manual tool grips exterior surface of PLIF device to rotate it, then the implant can be rotated within the disc space, but the PLIF device breaks or becomes deformed
Solution Approach 1:
The manual insertion tool is designed with grip elements that nest into recesses or engage with features on the exterior surface of the PLIF device. This nested configuration provides secure engagement for rotation while distributing mechanical stresses to prevent breakage or deformation of the implant during the rotation operation.
3Ease of operation
If PLIF device is inserted sideways with manual tool, then the implant can be positioned in the disc space, but the desired amount of distraction is not achieved
Solution Approach 1:
The rounded edges on the superior and inferior faces of the PLIF implant enable the device to be inserted sideways at an oblique angle while still achieving proper seating. The curved surfaces guide the implant into the disc space and allow for rotation to the final position, maximizing the distraction between vertebral bodies.
Solution Approach 2:
The implant design incorporates chamfered faces that allow insertion from an oblique angle rather than requiring direct axial insertion. This dimensional change in the insertion approach enables the implant to be seated sideways and then rotated, achieving the desired distraction amount that would be difficult to obtain with traditional straight-on insertion methods.
Data Source
AI summary
A posterior lumbar interbody fusion (PLIF) implant that comprises a body with substantially parallel posterior and anterior sidewalls, and a pair of superior and inferior faces. The implant is inserted via an insertion tool within a depression in the sidewalls of the implant. The insertion tool is secured to the side walls of the implant to prevent any bending or breaking of the implant or the inserter during implantation. Once inserted, the implant may be rotated approximately 90 degrees within the disc space. Because of the shape and size of the implant, the effective height of the implant within a patient's disc space is increased upon rotation.