Side-Loading Bone Anchor with Lateral Rod Insertion
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Solution Overview
Problem
Current bone anchors for spinal fixation often require complex procedures and may interfere with surrounding tissue, particularly when translating vertebral bodies to accommodate elongated rods, necessitating improved side-loading mechanisms for efficient and minimally invasive attachment.
Innovation Solution
A side-loading bone screw assembly featuring a C-shaped receiving portion, a crown member, and a clip, allowing for multi-axial positioning and easy insertion of a rod into a channel, with a set screw for final locking, which reduces interference with lateral tissue and facilitates pre-loading of locking components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional bone anchors with upward-opening channels are used, then the anchor can be easily placed in the bone and the rod can be laid on top, but the procedure becomes complex and interferes with surrounding tissue when translating vertebral bodies
Solution Approach 1:
The patent inverts the traditional channel orientation by opening the rod-receiving channel laterally (to the side) rather than upward. This allows the rod to be inserted from the side of the anchor body, enabling minimally invasive side-loading insertion while avoiding interference with surrounding tissue during vertebral body translation.
2Object-affected harmful factors
If side-loading mechanisms are implemented to reduce tissue interference, then tissue trauma is reduced, but the device structure becomes more complex
Solution Approach 1:
The anchor is segmented into distinct functional components: a bone-engaging portion (screw or hook), a receiving portion with lateral channel, and a locking mechanism. This segmentation allows each component to perform its specific function efficiently while maintaining overall structural simplicity suitable for side-loading insertion.
Solution Approach 2:
The rod is inserted into a channel within the anchor body, with the locking mechanism nested within the receiving portion. This nesting arrangement allows compact construction while maintaining the side-loading capability and reducing overall device bulkiness.
3Volume of moving object
If fixation elements are positioned directly beneath the rod as in CD system, then bulkiness is reduced, but side-loading and pre-loading capabilities are limited
Solution Approach 1:
The patent changes the dimension of rod access by opening the channel laterally instead of upward or from beneath. This lateral opening enables side-loading insertion while maintaining compact positioning of the fixation element, achieving both reduced bulkiness and enhanced versatility for minimally invasive procedures.
Data Source
AI summary
A side-loading bone anchor is provided, which may be used in cervical, thoracic, lumbar or sacral areas of the spine or other orthopedic locations. In one embodiment, the anchor includes an anchoring portion and a receiving portion. The anchoring portion is attached to a bone, and is connected to the receiving portion. A rod or other elongated support member is received in the receiving portion in contact with a crown member in the receiving portion and above the anchoring portion. The receiving portion, with or without the rod, may be rotated or pivoted with respect to the anchoring portion, and a set screw is threaded into the receiving portion to lock the rod within the receiving portion.