Pedicle Screw Rod Reduction Tool Alignment Mechanism
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Solution Overview
Problem
The placement of connecting rods in pedicle screw systems is challenging due to the narrow clearance between the rods and the receiving heads of pedicle screws, especially when three or more screws are involved, often requiring additional incisions for direct visualization and alignment.
Innovation Solution
A rod delivery tool with an elongate shaft and clamping mechanism that allows the connecting rod to be advanced and pivoted for alignment with pedicle screws, and a rod reduction tool with an alignment extension member to urge the connecting rod into alignment with the screw towers, facilitating secure seating without direct visualization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional open techniques are used for pedicle screw placement, then direct visualization and alignment are improved, but surgical invasiveness and complexity increase
Solution Approach 1:
The patent introduces a rod delivery tool as an intermediary device that facilitates rod passage through the percutaneous access device without requiring direct visualization. The tool includes a shaft that inserts through the PAD and a clamping mechanism that secures the rod, acting as a mediator between the rod and the receiving head to enable precise alignment while maintaining minimally invasive techniques
Solution Approach 2:
The rod delivery tool performs preliminary actions by pre-aligning the connecting rod with the receiving head of the pedicle screw before final insertion. The clamping mechanism pre-secures the rod in the correct orientation, and the shaft guides it through the PAD, preparing the system for seamless connection without requiring additional surgical exposure
2Object-affected harmful factors
If minimally invasive techniques are used for pedicle screw placement, then surgical invasiveness is reduced, but alignment precision and rod passage difficulty increase
Solution Approach 1:
The rod delivery tool serves as a mediator that enables precise alignment through the constrained percutaneous access device. The shaft provides a guided pathway that maintains alignment precision while the clamping mechanism ensures accurate positioning, all without requiring additional surgical incisions or direct visualization
Solution Approach 2:
The invention addresses the alignment challenge by introducing a new dimensional approach - using a delivery tool shaft that extends through the PAD to provide a third-dimensional guide pathway. This allows the rod to be aligned and inserted through the constrained access device by adding the dimension of the delivery tool's longitudinal shaft, rather than trying to improve alignment through traditional surgical exposure
3Volume of moving object
If the receiving head diameter is kept close to the rod diameter for compactness, then device compactness is improved, but rod insertion difficulty increases due to narrow clearance
Solution Approach 1:
The rod delivery tool acts as an intermediary that overcomes the narrow clearance problem between the rod and receiving head. The tool's shaft and clamping mechanism provide external guidance and positioning, allowing the rod to be inserted through the tightly fitted receiving head without requiring additional clearance or modifying the compact design
Solution Approach 2:
The clamping mechanism of the rod delivery tool performs preliminary positioning and alignment of the rod before insertion. By pre-aligning the rod with the receiving head opening and securing it in the correct orientation, the tool enables easy insertion through the narrow clearance without requiring the receiving head to be larger or less compact
4Strength
If three or more pedicle screws are used for spinal stabilization, then stabilization effectiveness is improved, but rod alignment and passage complexity increase
Solution Approach 1:
The rod delivery tool is designed as a universal device that can accommodate multiple pedicle screws and varying rod configurations. The tool can be used to pass rods through any number of receiving heads along the spinal column, providing a multi-functional solution that simplifies the passage process regardless of whether two or more screws are involved
Solution Approach 2:
For each pedicle screw in a multi-screw configuration, the rod delivery tool performs preliminary alignment and positioning actions. The clamping mechanism secures the rod in the correct orientation before each insertion, and the shaft guides it through the PAD, enabling systematic and simplified passage through multiple receiving heads without increasing overall procedural complexity
Data Source
AI summary
Rod delivery tools, methods for delivering a connecting rod of a pedicle screw system into seating slots of at least first and second long arm screw towers of a pedicle screw system, and a rod reduction tool and related methods for urging a distal leading end of a connecting rod and an opening of a long arm screw tower into alignment with one another, where the two are initially misaligned.