Bone Anchor Coupling Ring for In Situ Temporary Locking
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Solution Overview
Problem
Existing bone anchoring devices require pre-assembled assembly with the bone anchor, limiting their application in minimally invasive surgery and lacking an efficient mechanism for in situ placement and temporary locking without a rod or locking member.
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 and adjustment steps without a rod, suitable for minimally invasive surgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bone anchoring devices are pre-assembled with the bone anchor, then the assembly is secure and stable, but the applicability in minimally invasive surgery is limited and tissue intrusion increases
Solution Approach 1:
The bone anchoring device is divided into separate components: the bone anchor can be implanted first, and the coupling device with receiving part is attached later in situ. This segmentation allows minimally invasive implantation of the anchor followed by a less invasive attachment procedure for the coupling device, reducing overall tissue intrusion while maintaining secure assembly.
Solution Approach 2:
The bone anchor is implanted into the bone first as a preliminary action, creating a stable base. Then the coupling device is attached to the protruding head of the already-implanted anchor. This preliminary implantation allows for minimally invasive surgery while ensuring secure attachment, as the anchor is already in place to receive the coupling device without requiring pre-assembly.
2Adaptability or versatility
If an outer locking ring is used as compression member, then temporary locking without rod or locking member is enabled, but the device complexity increases
Solution Approach 1:
The outer locking ring serves multiple functions: it acts as a compression member to clamp the head, provides temporary locking capability without requiring a rod or separate locking member, and enables adjustment steps by moving between locked and unlocked states. This multi-functionality reduces the need for additional components, thereby limiting the increase in device complexity while providing versatile temporary locking capability.
Solution Approach 2:
The locking ring can be dynamically moved between different positions to provide temporary locking or unlocking states. This dynamic capability allows for adjustment steps during surgery where the coupling can be locked temporarily without permanent fixation, and unlocked when adjustment is needed, providing versatility without requiring complex additional mechanisms.
3Ease of operation
If in situ placement is performed without instrument, then the procedure is simpler, but excessive forces may be exerted causing injuries
Solution Approach 1:
A specially designed instrument serves as an intermediary tool to facilitate the attachment of the coupling device to the bone anchor head. The instrument includes engagement features that interact with the receiving part, allowing controlled application of forces during placement. This intermediary instrument enables in situ placement while preventing excessive forces from being exerted directly on the bone anchor or surrounding tissue, thus maintaining procedural simplicity while preventing injuries.
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
Facilitates secure and adjustable attachment to bone anchors, allowing for various surgical corrections and reducing tissue intrusion, enhancing the versatility and safety of spinal surgery.
Implementation Method 1
a locking ring (40) configured to clamp and lock the head (3) in the receiving part (20)
Implementation Method 2
the arms (105) of the instrument (100) are resiliently flexible, which gives a tactile response when attaching the instrument (100) to the coupling device (10)
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.