Spinal Fusion Disc Preparation Instrument with Rotating Rasp
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Solution Overview
Problem
Current spinal fusion systems lack precision in correlating the entry location of anchor blades into vertebral endplates with pre-scored locations, which can affect the effective deployment and integration of spinal implants.
Innovation Solution
A disc preparation instrument that includes a trial device for sizing, a depth stop to prevent over-insertion, and a rotating rasp element to create slots in vertebral endplates, ensuring precise alignment and depth settings for anchor plate deployment, along with an inserter assembly for controlled deployment of anchor plates into the scored locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a trial device with a pre-scoring blade is used to prepare vertebral endplates, then the endplate preparation function is provided, but precise correlation between anchor blade entry location and pre-scored location is difficult to achieve
Solution Approach 1:
The patent combines the trial device and scoring device into a single integrated instrument. The trial device body includes a scoring element that can be rotated to scribe the vertebral endplate, and the anchor blade is pre-attached to the trial device at a fixed position. This integration ensures that when the trial device is inserted to the correct depth, the anchor blade entry location automatically aligns with the pre-scored location on the endplate, eliminating the alignment precision problem that would exist with separate devices.
Solution Approach 2:
The trial device body serves as an intermediary between the surgeon's control and the anchor blade deployment. It includes a depth stop that prevents over-insertion and a scoring element that creates the precise entry location. The anchor blade is positioned relative to these controlling features, ensuring that when the depth stop contacts the vertebra, the anchor blade is at the exact correct position for penetration through the pre-scored endplate location.
2Measurement precision
If the trial device is inserted into the disc space, then sizing function is provided, but over-insertion cannot be prevented without a depth control mechanism
Solution Approach 1:
The depth stop is pre-configured on the trial device body at a specific distance from the anchor blade. Before insertion, the surgeon sets the desired depth by adjusting the depth stop position. This preliminary action ensures that when the trial device is inserted, the depth stop will contact the vertebra at the exact correct depth, preventing over-insertion before the actual implant deployment occurs.
Solution Approach 2:
The depth stop provides tactile feedback to the surgeon during insertion. When the depth stop contacts the vertebral body, it creates a mechanical stop that prevents further insertion. This feedback mechanism allows the surgeon to know precisely when the correct insertion depth is reached, ensuring both accurate sizing and reliable depth control for the subsequent implant deployment.
3Ease of manufacture
If a fixed scoring mechanism is used, then endplate slotting is provided, but adaptability to different implant depths is limited
Solution Approach 1:
The scoring element is designed to be rotatable relative to the trial device body, transforming a static mechanism into a dynamic one. The scoring element can be rotated into different positions, allowing it to engage the endplate at various depths and orientations. This dynamic capability enables the same simple scoring mechanism to adapt to different implant depths and surgical requirements without complicating the overall device structure.
Solution Approach 2:
The scoring element is separated as a distinct, movable component from the trial device body, allowing it to be rotated independently. This segmentation enables the scoring mechanism to adapt to different depths while keeping the rest of the trial device structure simple and easy to manufacture. The rotatable scoring element can be positioned at different angles and depths to match the specific surgical requirements for each patient.
Data Source
AI summary
A system for fusing together opposing vertebra of a spine that defines a disc space therebetween. The system comprises a disc preparation instrument and an inserter assembly for use in the interbody fusion procedure. Disc preparation instrument comprises an elongate handle supporting a trial device at one end thereof. Inserter assembly comprises an elongate inserter supporting at one end thereof an interbody cage implant for insertion into the disc space. Disc preparation instrument provides a scoring element that scribes vertebral endplates at an appropriate scored location for anchor blades on the cage implant to engage the vertebral bodies. Inserter is used to introduce cage implant with anchor blades into the disc space to an appropriate depth so that the blades will be precisely positioned at the scored location created by the scoring element for penetration into the vertebral endplates.