Collapsible Surgical Fastener for Stable Proximal Humerus Fixation
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Solution Overview
Problem
Current angularly stable lateral plating constructs for treating proximal humeral fractures suffer from secondary loss of fixation, varus mal-alignment, and screw cut-out or cut-through due to instability of the medial collum, insufficient bony support, and inadequate screw anchoring in the subchondral bone.
Innovation Solution
A surgical fastener with a cannulated collapsible fastening body and a non-threaded pin, featuring a rigid shaft and a flexible mesh portion, which expands radially upon insertion to enhance anchoring and fixation by increasing the footprint in the bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lateral plating constructs are used for proximal humeral fractures, then initial fixation can be achieved, but secondary loss of fixation and screw cut-out occur due to insufficient anchoring in subchondral bone
Solution Approach 1:
The fastener incorporates a collapsible body that transitions from a compressed delivery state to an expanded deployed state. The collapsible body includes a body portion that can be compressed during insertion and then expands within the bone cavity, creating stable fixation. This dynamic transformation allows the same structure to provide both ease of insertion and strong anchoring capability.
Solution Approach 2:
The pin is nested within the passage of the collapsible fastening body during delivery. The pin having a non-threaded shaft at least partially disposed within the passage allows for compact packaging and easy insertion. Once deployed, the pin remains positioned within the expanded body, creating a stable anchored structure that prevents screw cut-out through the combination of the expanded body's friction fit and the pin's positioning within the bone.
2Ease of operation
If conventional screws are used, then fixation can be applied, but varus mal-alignment occurs due to instability of the medial collum
Solution Approach 1:
The fastener is divided into distinct functional components: a collapsible fastening body that provides the anchoring structure and a separate pin that provides additional stability. The collapsible body includes a body portion and a pin portion that can be independently positioned. This segmentation allows the pin to specifically address medial collum stability while the expanded body provides overall fixation, preventing varus mal-alignment through distributed stability.
3Productivity
If traditional fasteners are used, then insertion can be performed, but inadequate support of the head fragment occurs due to insufficient footprint
Solution Approach 1:
The collapsible body transitions from a compressed state during insertion to an expanded state upon deployment. During insertion, the collapsible body is compressed to fit through the delivery system, enabling efficient insertion. Once positioned within the bone cavity, the body expands radially outward, significantly increasing its footprint and providing broad support for the head fragment. This dynamic size change allows the same structure to provide both easy insertion and extensive anchoring surface area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The expandable design improves fixation and reduces complications by providing stable anchoring and support to the humeral head fragment, minimizing rotation and distal translation, thereby enhancing fracture healing.
Implementation Method 1
The mesh portion may be comprised of a flexible material, and in an actuated configuration of the surgical fastener, a portion of the mesh portion may be expanded outward from the passage
Implementation Method 2
a pin having a non-threaded shaft at least partially disposed within the passage and an enlarged tip
Data Source
AI summary
A surgical fastener includes a cannulated collapsible fastening body having a trailing end and a leading end and defining a passage extending from the trailing end to the leading end, and a pin having a non-threaded shaft at least partially disposed within the passage and an enlarged tip. A method of using the surgical fastener includes engaging an end of a driver with a recess in a head of the surgical fastener, including inserting an extension at the end of the driver into the passage, and inserting the fastener into a bore in a bone during which the extension of the driver abuts a trailing end of the shaft of the pin to prevent the pin from moving in a direction from the leading end to the trailing end relative to the fastening body.