Spinal Derotator with Ball Joint for Misaligned Vertebrae
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Solution Overview
Problem
In spinal surgery, aligning vertebrae with complex curvature and irregularities is challenging due to the difficulty in securing implants across multiple vertebrae, especially when they are severely misaligned, making conventional instrumentation ineffective.
Innovation Solution
A system comprising elongate derotator members and linking members with transverse members, allowing for the alignment and stabilization of vertebrae by engaging implants on opposite sides of the spine, with features like split distal end portions and ball joints for adjustable engagement and stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional instrumentation is used to secure implants across multiple vertebrae, then standard spinal fixation can be achieved, but alignment becomes impossible when vertebrae are severely misaligned
Solution Approach 1:
The derotator member incorporates a ball joint at its proximal end that allows dynamic articulation and adjustment of the longitudinal axis orientation. This enables the instrument to adapt to severely misaligned vertebrae by permitting angular adjustments in multiple directions, making it possible to engage implants when conventional rigid instrumentation would fail
Solution Approach 2:
The derotator member is divided into distinct functional segments: a distal end portion for engaging the implant, a ball joint for angular adjustment, and a proximal end portion for connection to the rod. This segmentation allows each component to perform its specific function independently, facilitating engagement of misaligned vertebrae while maintaining ease of operation
2Manufacturing precision
If multiple vertebrae are repositioned relative to multiple planes to achieve desired alignment, then spinal curvature correction is improved, but the complexity of the procedure increases
Solution Approach 1:
The derotator member serves multiple functions: it acts as a connector between the rod and implant, provides angular adjustment capability through the ball joint, and enables repositioning of vertebrae relative to multiple planes. This multi-functionality allows a single instrument to handle complex realignment requirements without requiring multiple specialized tools, thereby reducing procedural complexity while maintaining alignment precision
3Adaptability or versatility
If the distal end portion of the derotator member is split to engage the implant, then engagement capability is improved, but structural integrity may be compromised
Solution Approach 1:
The distal end portion of the derotator member is split into two separate arms that can independently engage the implant. This segmentation provides adaptability by allowing the split arms to conform to the implant geometry and accommodate angular misalignment, while the overall structure maintains strength through the continuous body of the derotator member and proper material selection
Data Source
AI summary
Systems, assemblies, components and methods for correcting alignment of one or more vertebrae of a spine are provided. A first elongate derotator member includes a first elongate element having a first proximal end portion and a first distal end portion. The first distal end portion is releasably engageable with a first implant implanted in one of the vertebrae. A second elongate derotator member comprising a second elongate element is releasably engageable with a second implant implanted in the same vertebra. A transverse member is engageable with the first and second elongate elements. A first channel extends axially through the first elongate element and a second channel extends axially through the second elongate element such that a proximal end portion of the first implant can be accessed from a proximal end portion of the first elongate element by inserting a tool through the first channel and a proximal end portion of the second implant can be accessed from a proximal end portion of the second elongate element by inserting the tool or another tool through the second channel.