Occipital Fixation Assembly Using Threaded Post and Offset Extension
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Solution Overview
Problem
Existing occipital fixation techniques face challenges in securely anchoring surgical implants to the skull, particularly in resisting forces and moments at the occipitocervical junction, while minimizing the risk of screw pull-out and cerebellar injury.
Innovation Solution
An occipital fixation assembly comprising a mounting plate with a threaded post, a coupling member, and a fixation nut that securely engages with the skull, utilizing barbs for anchoring and an offset extension to support a surgical rod, reducing the likelihood of pull-out and cerebellar injury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If maximum screw length is used to provide adequate purchase, then resistance to pullout is improved, but risk of cerebellar injury increases
Solution Approach 1:
The fixation assembly is divided into separate components: a mounting plate with barbs for bone anchoring, a threaded post, and a fixation nut. This segmentation allows the mounting plate to be positioned and secured independently, enabling precise control over screw length and insertion depth to achieve adequate purchase without exceeding the safe depth that could injure the cerebellum.
Solution Approach 2:
The threaded post acts as an intermediary element between the mounting plate and the fixation nut. It provides a controlled threading mechanism that allows gradual engagement and secure fixation while maintaining precise control over the insertion depth, thereby preventing cerebellar injury while ensuring adequate bone purchase.
2Stability of the object's composition
If rigid metallic loops and rectangles are fixed to bone with screws or wires, then stabilization is improved, but device complexity increases
Solution Approach 1:
The invention merges the mounting plate and fixation nut into a single integrated assembly that can be positioned and secured as one unit. This combination simplifies the surgical procedure and reduces the complexity compared to separate loops and rectangles fixed with multiple screws or wires, while maintaining adequate stabilization through the integrated barb structure.
3Strength
If plate or rod constructs with screws are used, then rigidity is improved, but difficulty of detecting and measuring correct screw size increases
Solution Approach 1:
The invention changes the parameter of fixation control from pre-selected screw sizes to a adjustable threaded post system. The threaded post allows dynamic adjustment of the fixation depth and length during surgery, eliminating the difficulty of pre-selecting the correct screw size while maintaining the required rigidity through controlled engagement of the fixation nut.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The assembly provides stable and secure attachment of surgical rods, reducing the risk of pull-out and cerebellar injury by anchoring the mounting plate and coupling member firmly to the skull, facilitating effective bone fusion and minimizing the need for external immobilization.
Implementation Method 1
A threaded post extends from the first mounting plate. A fixation nut, configured to threadably engage the threaded post of the first mounting plate, is rotatable about the threaded post and translatable therealong.
Data Source
AI summary
An occipital fixation assembly is provided. The occipital fixation assembly includes a first mounting plate configured for placement within a sinus cavity adjacent a rear portion of a skull of a patient. A threaded post extends from the first mounting plate. A coupling member includes an aperture configured to receive the threaded post therethrough. The coupling member includes an offset extension configured to support a surgical rod thereon. A fixation nut configured to threadably engage the threaded post of the first mounting plate is rotatable about the threaded post and translatable therealong. The fixation nut is rotatable with respect to the first mounting plate and the coupling member such that rotation of the fixation nut in a predetermined direction brings the first mounting plate and the coupling member toward one another and into secured engagement with the skull of a patient.