Pedicle Screw Ball Joint for Spinal Fixation
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Solution Overview
Problem
Existing spinal fixation systems face challenges in providing adequate freedom of angulation and rotation, long-term durability, and preventing screw loosening and migration, especially in dynamic stabilization devices, which can lead to complications such as pain and tissue damage.
Innovation Solution
A bone screw system with a fixation element featuring a threaded segment, a neck segment, a head segment with a movable ball, a set screw, and an anchoring element with protrusions, allowing for controlled motion and secure engagement with the spinal column, and a pin to connect components securely, limiting excessive rotation and movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid screws are used to stabilize a spinal segment, then fixation strength is improved, but the ability to accommodate dynamic motion and angulation is reduced
Solution Approach 1:
The patent applies the dynamics principle by incorporating a ball joint mechanism that allows the screw head to rotate and articulate relative to the implant. This enables the rigid screw shaft (for strength) to be coupled with a movable connection (for adaptability), resolving the contradiction between fixation strength and freedom of motion.
2Adaptability or versatility
If additional connectors are added to achieve proper variability of the screw/implant interface, then adaptability is improved, but device complexity and operating time increase
Solution Approach 1:
The patent merges the functions of multiple connectors into a single integrated ball joint mechanism. The ball joint combines rotational freedom, angular adjustment, and mechanical coupling in one component, eliminating the need for separate connectors and reducing overall device complexity while maintaining adaptability.
3Adaptability or versatility
If dynamic stabilization is implemented with posterior pedicle screws, then motion accommodation is improved, but stress on the screw increases leading to loosening and migration
Solution Approach 1:
The ball joint mechanism allows the screw to dynamically adjust its position and orientation in response to physiological loads and motions. This dynamic capability distributes stresses more effectively and prevents the rigid stress concentrations that lead to screw loosening and migration, thereby maintaining reliability while accommodating motion.
4Ease of operation
If manual manipulation is used to lock and secure components, then fixation is achieved, but displacement of screw and implant may occur
Solution Approach 1:
The ball joint mechanism is designed to self-align and self-lock through its mechanical geometry. When the implant is inserted, the ball joint automatically settles into its proper position and locks via friction and geometric constraints, eliminating the need for manual manipulation that could cause displacement and ensuring precise component positioning.
Data Source
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AI summary
The present invention provides a pedicle screw system, which may include a bone fixation element having an elongate body The elongate body may include a threaded segment having one or more spiral-oriented grooves, gel neck segment adjacent to the threaded segment, and a head segment which is able to receive and/or couple to an orthopedic instrument or implant The pedicle screw system may further include an anchoring element movably positionable about the bone fixation element. The anchoring element may include one or more elongate teeth which may be slidably positionable into a desired tissue region.