Modular Pedicle Screw Assembly with Interchangeable Inner Collets
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Solution Overview
Problem
Current spinal fixation pedicle screw systems require a large inventory of different types to address various spinal pathologies, increasing costs and complexity due to their design, which often involves complicated constructions and multiple components for locking and movement limitations.
Innovation Solution
A modular pedicle screw assembly with a bone screw, uniaxial or polyaxial inner collets, and a seat with an actuator, allowing for configurable uniaxial or polyaxial movement by selecting appropriate inner collets, reducing the need for multiple screw types and simplifying the assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple types of pedicle screws are used to address various spinal pathologies, then the ability to treat different spinal conditions is improved, but inventory costs and complexity increase
Solution Approach 1:
The pedicle screw assembly is designed with a universal bone screw head and interchangeable inner collets that can be selected based on the specific spinal pathology being treated. This allows a single base assembly to perform multiple functions (uniaxial movement in different planes, polyaxial movement) by simply changing the inner collet component, thereby reducing the need to maintain multiple complete screw system inventories while maintaining the ability to address various spinal conditions
2Adaptability or versatility
If multiple types of pedicle screws are maintained in inventory, then various spinal pathologies can be treated, but sterilisation and shipping costs increase
Solution Approach 1:
The pedicle screw system is segmented into modular components: a universal bone screw assembly and interchangeable inner collets. Only the inner collets need to be sterilized and shipped separately, while the main bone screw assembly can be sterilized once and reused. This segmentation significantly reduces the frequency and cost of sterilization and shipping operations compared to maintaining multiple complete screw systems in inventory
3Reliability
If complicated constructions with multiple components are used for locking and movement limitation, then movement control is improved, but assembly complexity increases
Solution Approach 1:
The inner collet integrates multiple functions into a single component: it provides movement control (limiting rotation or allowing polyaxial movement), structural support, and acts as the interface for the locking mechanism. The actuator threads directly into the inner collet to engage the locking mechanism, eliminating the need for separate locking components and simplifying the overall assembly construction while maintaining reliable movement control
Data Source
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AI summary
The present invention is broadly directed to a modular pedicle screw assembly (10) for immobilisation and stabilisation of spinal segments in a patient (not shown). The modular pedicle screw assembly (10) generally comprises a bone screw (12), a uniaxial inner collet (14) arranged to cooperate with a head (16) of the bone screw (12), a seat (18) arranged to provide seating for retention of the inner collet (14), and an inner collet actuator (20) designed to engage the seat (18) to activate the inner collet (14) for clamping about the head (16) of the bone screw (12).