Polyaxial Bone Anchor Locking Instrument with Dual Tube Actuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In spinal surgery, existing polyaxial bone anchoring devices require frequent adjustments of bone anchoring elements and rods, which can be cumbersome and time-consuming, especially when multiple segments of the spinal column need to be corrected or stabilized.
Innovation Solution
An instrument with a tube assembly and actuator assembly that allows for independent locking and unlocking of the bone anchor head, enabling temporary locking without a set screw, facilitating multiple angular adjustments and allowing the device to function like a monoaxial anchor, with a modular design for versatility and safety features like tactile and audible feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyaxial bone anchoring device uses a locking ring and set screw mechanism for securing the head, then the device provides stable locking, but the adjustment process becomes time-consuming and complex requiring multiple tools
Solution Approach 1:
The patent combines the locking ring and set screw into a single integrated locking element that performs both locking functions simultaneously. This merging eliminates the need for separate tools and sequential operations, reducing adjustment time while maintaining reliable locking through the combined mechanical action of the integrated elements
Solution Approach 2:
The locking element is designed to perform multiple functions: it provides both the locking ring's radial constraint and the set screw's axial securing action through a single component. This multi-functionality allows one element to replace two separate components, simplifying the adjustment process while ensuring stable fixation
2Adaptability or versatility
If frequent adjustments of bone anchoring elements and rods are performed, then multiple spinal segments can be corrected, but the procedure becomes cumbersome and increases operating complexity
Solution Approach 1:
The instrument incorporates a dynamic locking mechanism that allows the locking element to be quickly engaged and disengaged through rotational movement. This dynamic design enables frequent adjustments to be made easily, maintaining adaptability for correcting multiple spinal segments while reducing operational complexity through the simple rotate-to-lock/rotate-to-release mechanism
Solution Approach 2:
The instrument is pre-configured with the locking element and engagement features before use. The receiving part includes pre-formed engagement structures that guide the locking element into position, eliminating the need for complex alignment procedures during frequent adjustments. This preliminary preparation simplifies repeated adjustment operations
3Ease of operation
If the instrument allows independent locking and unlocking of the head, then temporary locking is achieved without set screw, but the mechanism requires precise control to prevent operating errors
Solution Approach 1:
The instrument incorporates tactile feedback through engagement ridges and grooves that provide distinct tactile sensations when the locking element is properly engaged or disengaged. Audible feedback is also provided through clicking sounds at specific rotational positions. This feedback mechanism ensures precise control during locking and unlocking operations, preventing errors while maintaining simple operation through intuitive tactile and audible cues
Solution Approach 2:
The instrument uses visual indicators such as colored markings or transparent sections that change appearance or position to indicate the locked and unlocked states. This visual feedback provides clear, error-proof indication of the current state, enhancing reliability by preventing premature removal or incorrect operation while keeping the interface simple and intuitive
Data Source
AI summary
An instrument for locking and unlocking a head of a bone anchor relative to a receiving part of a polyaxial bone anchoring device includes a tube assembly with an inner tube and an outer tube at least partially around the inner tube, and an actuator assembly including an actuating mechanism movable from a first orientation to a second orientation to displace the inner tube and the outer tube relative to one another between a first axial position configured to unlock the bone anchoring device such that the head is pivotable relative to the receiving part, and a second axial position configured to lock the head. The actuator assembly is adjustable between a first configuration where the tube assembly assumes the first axial position when the actuating mechanism is moved, and a second configuration where the tube assembly assumes the second axial position when the actuating mechanism is moved.