Bone Anchor Coupling With Outer Ring for In Situ Placement
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Solution Overview
Problem
Existing bone anchoring devices require pre-assembled assembly with the bone anchor, limiting their applicability in clinical scenarios and necessitating excessive force application during in situ placement, which can cause injuries.
Innovation Solution
A coupling device with an outer locking ring and an instrument that allows for in situ placement onto an implanted bone anchor, enabling temporary locking without a rod, and facilitating minimally invasive surgery by reducing the required space for implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an inner cap compression member is used to clamp and lock the head, then the locking function is achieved, but the device requires pre-assembled configuration which limits clinical applicability
Solution Approach 1:
The coupling device is divided into separate components: the receiving part with head receiving portion and the outer locking ring, which can be applied independently in situ after bone anchor insertion, eliminating the need for pre-assembly and enabling greater clinical versatility
Solution Approach 2:
An instrument with a pushing member acts as an intermediary tool to apply controlled force through the outer locking ring during in situ placement, facilitating the compression and locking action without requiring pre-assembled configuration
2Ease of operation
If in situ placement is performed without specialized instrument, then procedural flexibility is improved, but excessive force may be applied causing injuries
Solution Approach 1:
The instrument serves as a mediator between the surgeon and the coupling device, providing a controlled interface that limits the force applied during in situ placement to safe levels while maintaining procedural flexibility
Solution Approach 2:
The instrument is designed with a pushing member that provides controlled, gradual compression force during placement, cushioning against excessive force application before it can cause injury to surrounding tissues
3Adaptability or versatility
If coupling device allows temporary locking without rod, then adjustment flexibility is improved, but additional locking mechanisms are required for final securing
Solution Approach 1:
The outer locking ring can be dynamically positioned between locked and unlocked states, enabling temporary locking during adjustment phases and final securing when needed, providing adaptability without permanent complex mechanisms
Solution Approach 2:
The locking state is changed by adjusting the position of the outer locking ring along the receiving part, allowing transition between locked and unlocked positions to accommodate different surgical phases from adjustment to final securing
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
Enables safe, gentle placement and adjustment of the coupling device in situ, allowing for various correction steps during surgery without causing injuries, and supporting minimally invasive procedures.
Implementation Method 1
an outer locking ring which forms a compression member to exert pressure onto an inserted head
Implementation Method 2
The head receiving portion has a plurality of slits that render the head receiving portion flexible so that when pressure is exerted onto the head receiving portion by the locking ring, the head can be clamped
Data Source
AI summary
A coupling device includes a receiving part having a head receiving portion for pivotably receiving a head of a bone anchor and a rod receiving portion defining a recess for receiving the rod, the rod receiving portion having an engagement structure for engaging a locking member to lock the rod in the recess and a first engagement surface different from the engagement structure for engaging an instrument, wherein the first engagement surface is formed away from radially outwardly facing regions of the rod receiving portion, and a locking ring positionable around the head receiving portion and having a second engagement surface for engaging the instrument. The locking ring can assume an insertion position where the head of the bone anchor is insertable into the head receiving portion, and a pre-locking position where the head is prevented from removal from the head receiving portion.