Rotatable Spinal Reduction Instrument Dovetail Interlock
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Solution Overview
Problem
Current spinal implant systems face challenges in securely attaching and detaching bone fasteners and rods during surgical procedures, particularly in managing sagittal angulation and preventing unintended detachment or 'pop-off' during spinal rod reduction, which can complicate deformity correction and fusion procedures.
Innovation Solution
The spinal implant reduction instrument features rotatable arms with tapered projections that interlock with bone fasteners via dovetail connections, allowing for sagittal angulation and secure attachment, while a reducer assembly facilitates the introduction and reduction of spinal rods, ensuring stable engagement and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotatable arms with tapered projections are used to interlock with bone fasteners, then secure attachment and sagittal angulation are achieved, but device complexity increases
Solution Approach 1:
The arms are designed to be rotatable relative to the longitudinal axis, allowing dynamic adjustment between capture and release orientations. This enables the instrument to adapt to different surgical needs while maintaining secure attachment when engaged, resolving the contradiction between reliability and operational flexibility.
Solution Approach 2:
The instrument is divided into multiple rotatable arms that can independently engage with bone fasteners. Each arm functions as a separate module with tapered projections for interlocking, allowing selective engagement and disengagement while maintaining overall system stability.
2Reliability
If rotatable arms with dovetail connections are used for bone fastener engagement, then detachment prevention is improved, but ease of operation deteriorates
Solution Approach 1:
The dovetail connections are combined with rotatable arms that can be easily manipulated between engaged and disengaged states. The rotation mechanism provides mechanical advantage, allowing surgeons to securely engage or release bone fasteners with minimal force, thus maintaining ease of operation while ensuring reliable attachment.
3Manufacturing precision
If tapered projections with dovetail connections are used for interlocking, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The tapered projections feature asymmetric dovetail connections with specific geometric profiles. This asymmetric design provides precise mating surfaces that are easier to manufacture with standard machining processes compared to symmetric complex joints, while still achieving high manufacturing precision for reliable interlocking.
Data Source
AI summary
A surgical instrument includes spinal implant reduction instrument defining a longitudinal axis. The spinal implant reduction instrument includes a first member connected to a body. The first member includes a tapered projection configured to interlock to a first mating recess of a bone fastener. A second member is connected to the body. The second member includes a tapered projection configured to interlock to a second mating recess of the bone fastener. At least one of the members is rotatable relative to the longitudinal axis for connecting the members to the bone fastener. Systems, spinal constructs, implants and methods are disclosed.