Spinal Instrument Set Screw Retention Mechanism
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Solution Overview
Problem
Existing spinal fixation systems face complications during surgery due to the risk of set screws falling off screw drivers and into the surgical site, causing delays and contamination, especially when using tubes for derotation and alignment procedures.
Innovation Solution
A spinal instrument with a set screw loading and retention mechanism that includes a first tube with an inner lumen and a retention mechanism, allowing for secure loading and releasable retention of set screws, featuring a screw slot and a threaded portion with optional features like a pin, ball, or spring to prevent loss and facilitate precise alignment and tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a friction fit is used between the set screw and the tip of the screw driver, then the set screw can be easily loaded, but the set screw may fall off the screw driver onto the floor, into one of the tubes, or into the surgical site
Solution Approach 1:
A retention mechanism is introduced as an intermediary component between the set screw and the screw driver. This mechanism includes a retention feature on the screw driver that engages with a corresponding feature on the set screw, providing secure retention while allowing controlled release during the surgical procedure.
Solution Approach 2:
The set screw is pre-loaded onto the screw driver using the retention mechanism before the surgical procedure begins. This preliminary loading ensures that the set screw is securely held and cannot fall off during subsequent manipulation and insertion operations.
2Ease of operation
If tubes are used for derotation and alignment procedures, then alignment and positioning can be facilitated, but the risk of set screws falling into the tubes increases
Solution Approach 1:
The retention mechanism acts as an intermediary safeguard between the set screw and the surgical environment. By securing the set screw to the screw driver throughout the alignment and derotation procedures, it prevents the set screw from accidentally falling into the tubes or surgical site, thereby eliminating the contamination risk while maintaining full alignment capability.
3Productivity
If the set screw is placed on the tip of the screw driver prior to insertion, then the procedure can be streamlined, but complications such as delays and contamination may occur
Solution Approach 1:
The retention mechanism provides continuous secure engagement between the set screw and screw driver throughout the entire surgical procedure. This eliminates the need for stopping to retrieve lost set screws or address complications, thereby maintaining streamlined efficiency and preventing surgical delays while keeping the procedure simplified.
Data Source
AI summary
A spinal instrument with a set screw loading and retention mechanism includes a first tube, a screw slot, and a retention mechanism. The first tube includes an inner lumen disposed concentric and proximate to a head portion of a bone screw. The screw slot is disposed along a portion of the first tube at a distance from the head portion of the bone screw and is configured for loading of a set screw for locking a spinal rod within the head portion of the bone screw. The retention mechanism is disposed along at least a portion of the inner tube configured to selectively retain the set screw. In other features, the first tube includes either an internal rod reduction tube or a screw extender tube.