Polyaxial Bone Anchor Locking Ring for Intraoperative Repositioning
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Solution Overview
Problem
Existing polyaxial bone anchoring devices require repeated adjustments of the bone anchoring element and spinal rod during surgery, which can be cumbersome and may exert pressure on vertebrae, and lack versatility in clinical applications.
Innovation Solution
A polyaxial bone anchoring device with a flexible head receiving portion and a clamping ring that allows for independent locking and unlocking of the bone anchoring element, enabling adjustments without exerting pressure on vertebrae and allowing for modular combinations of anchoring elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If repeated adjustments of bone anchoring element and rod are performed during surgery, then positioning accuracy is improved, but surgical time and complexity increase
Solution Approach 1:
The device employs a dynamic clamping mechanism where the clamping ring can be moved between locked and unlocked positions. This allows the bone anchoring element to be adjusted to different angular positions before final locking, enabling repeated positioning adjustments without requiring complete disassembly and reassembly of the system, thus reducing surgical time while maintaining positioning accuracy.
Solution Approach 2:
The receiving part is divided into distinct functional segments: a head receiving portion that accommodates the bone anchoring element, a rod receiving portion, and a clamping ring mechanism. This segmentation allows independent adjustment of the bone anchoring element's angular position relative to the rod, facilitating quick repositioning without affecting other components and reducing overall surgical time.
2Adaptability or versatility
If repeated adjustments are performed, then positioning flexibility is improved, but pressure on vertebrae increases
Solution Approach 1:
The clamping ring acts as an intermediary mechanism between the bone anchoring element and the rod. It provides a controlled locking and unlocking function that allows adjustments to be made without directly manipulating the bone anchoring element itself, thereby avoiding repeated insertion and removal that would exert harmful pressure on the vertebrae.
Solution Approach 2:
The device allows the bone anchoring element to be preliminarily positioned in the head receiving portion at the desired angular orientation before final locking. This preliminary positioning can be adjusted without exerting pressure on the vertebrae, and once satisfied, the clamping ring is engaged to lock the position, avoiding the need for repeated adjustments that would harm the vertebrae.
3Productivity
If independent locking and unlocking of bone anchoring element is enabled, then operational efficiency is improved, but device complexity increases
Solution Approach 1:
The locking and unlocking functions are merged into a single integrated clamping ring mechanism. By moving this single component, both locking and unlocking actions are achieved without requiring separate mechanisms or instruments, thereby improving operational efficiency while minimizing the increase in device complexity.
Solution Approach 2:
The clamping ring serves multiple functions: it locks the bone anchoring element in position, allows for unlocking and repositioning, and maintains the angular relationship between the bone anchoring element and the rod. This multi-functionality reduces the need for additional components, improving operational efficiency without proportionally increasing device complexity.
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 improved handling and adjustments during surgery, reduces tissue damage, and offers a versatile system for various clinical needs, reducing inventory costs and providing a wider range of implant options.
Implementation Method 1
the head receiving portion being at least partially flexible
Data Source
AI summary
A bone anchoring device includes a receiving part for coupling a rod to a bone anchoring element, the receiving part having a first end, a second end, a recess at the first end for receiving the rod, and a compressible head receiving portion at the second end for accommodating a head of the bone anchoring element, a pressure member positionable in the receiving part to exert pressure on the head, and a clamping ring positionable around the head receiving portion and movable towards the first end of the receiving part to a locking position where the clamping ring exerts force on and compresses the head receiving portion. In the locking position, at least part of the clamping ring that faces the first end of the receiving part is exposed to the outside to facilitate movement of the clamping ring away from the first end of the receiving part.