Spinal Fixation Guide Extension for Minimally Invasive Rod Alignment
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Solution Overview
Problem
Current spinal fixation constructs face challenges in aligning and securing fixation rods within posterior fixation anchors, especially under minimally invasive conditions, due to vertical and horizontal misalignment of vertebrae and the need for larger incisions to achieve proper alignment.
Innovation Solution
The spinal fixation system includes a guide extension that helps align and seat the fixation rod within the anchor housing, with integral reduction features and separate reduction tools to realign vertebrae and secure the rod, allowing for minimally invasive procedures with reduced incision size by using a break-off extension guide and adjustable angle rod inserters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional open procedures are used to align and seat the fixation rod in the rod channel, then proper alignment can be achieved, but the incision length and muscle stripping increase
Solution Approach 1:
A guide extension is introduced as an intermediary component between the rod inserter and the rod channel. The guide extension includes alignment features that extend into the rod channel to guide and align the fixation rod during insertion, enabling precise alignment through a minimally invasive approach without requiring large incisions or extensive muscle stripping
Solution Approach 2:
The guide extension is pre-positioned in the rod channel before rod insertion. The alignment features are already in place to receive and guide the fixation rod, allowing for precise alignment to be achieved during the minimally invasive procedure without requiring subsequent realignment maneuvers that would necessitate larger incisions
2Adaptability or versatility
If vertebrae are out of alignment leaving anchors offset vertically and horizontally, then the fixation construct can accommodate misalignment, but rod alignment and seating becomes more difficult
Solution Approach 1:
The rod inserter is designed with adjustable angulation capabilities, allowing the inserter to be dynamically repositioned at different angles to match the offset between anchors. This dynamic adjustment enables the rod to be seamlessly inserted even when anchors are vertically or horizontally misaligned, maintaining ease of operation despite the adaptability requirement
Solution Approach 2:
The guide extension serves as a mediator that bridges the gap between offset anchors. The alignment features of the guide extension compensate for the vertical and horizontal offset by providing a guided pathway that accommodates the misalignment while still enabling proper rod seating in the rod channel
3Object-affected harmful factors
If minimally invasive access conditions are used, then tissue disruption is reduced, but the difficulty of aligning the rod with the rod channel increases
Solution Approach 1:
The guide extension is introduced as a minimally invasive intermediary tool that can be positioned through small incisions. The alignment features extend into the rod channel to provide guidance, enabling rod alignment to be achieved through minimally invasive access without requiring large incisions or extensive muscle stripping that would increase tissue disruption
Solution Approach 2:
The system replaces the need for large-incision-based mechanical alignment with a guided insertion system. The guide extension provides mechanical guidance through alignment features that work with the rod inserter to achieve proper rod seating through minimally invasive access, substituting the traditional mechanical advantage of large incisions with a more refined guidance mechanism
Data Source
AI summary
This application describes surgical instruments and implants for building a posterior fixation construct across one or more segments of the spinal column. Extension guides are provided that attach to bone anchors implanted within the spine. The extension guides have a guide channel that align with a rod channel in the anchor to help direct the rod to the anchor. Instruments are provided to aid in insertion and positioning or the rod.