Adjustable Interspinous Spacer Arms for Variable Vertebral Spacing
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Solution Overview
Problem
Conventional interspinous spacers have a fixed distance between arms, limiting their adaptability to varying vertebral spacings, necessitating multiple sizes for different surgical applications.
Innovation Solution
An interspinous spacer with an actuator screw mechanism allowing adjustable deployment positions, enabling a range of arm separations from 8 to 16 mm, facilitated by a threaded actuator screw and pin system for precise vertebral engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional interspinous spacers use a fixed distance between arms, then the structure is simple and easy to manufacture, but the adaptability to varying vertebral spacings is limited
Solution Approach 1:
The spacer transitions from a fixed static structure to a dynamic adjustable structure. The actuator screw mechanism allows the arms to be positioned at different distances from each other, enabling the device to adapt to various vertebral spacings. The threaded channel and locking features provide controlled movement and stable positioning at selected configurations.
Solution Approach 2:
The device allows changing the key parameter of arm separation distance. By rotating the actuator screw within the threaded channel, the position of the arm actuator changes, which directly adjusts the distance between the first and second arms. This parameter adjustment enables adaptation to different vertebral spacings without requiring multiple fixed-size devices.
2Adaptability or versatility
If multiple sizes of spacers are used for different surgical applications, then the adaptability is improved, but the device complexity and inventory requirements increase
Solution Approach 1:
A single spacer design incorporates multiple functions by including an adjustable mechanism. Instead of requiring separate spacers for different spacing requirements (e.g., 8mm, 10mm, 12mm, 14mm, 16mm), one universal spacer with the actuator screw mechanism can achieve all these configurations, eliminating the need for multiple specialized devices.
Solution Approach 2:
The patent combines multiple spacer configurations into a single device. The adjustable mechanism integrates various arm separation distances (8-16mm range) into one physical device, merging what would traditionally require multiple separate spacers into a single multi-functional unit.
3Ease of operation
If an adjustable actuator mechanism is added to the spacer, then the surgical flexibility is enhanced, but the device complexity increases
Solution Approach 1:
The actuator screw mechanism is designed to be self-contained and self-operating within the spacer structure. The screw threads directly engage with the threaded channel in the body, and the locking features (locking insets with teeth engaging the disc teeth) provide automatic positioning and securing without requiring external tools or complex actuation systems. The surgeon simply rotates the screw to adjust and lock the position.
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 spacer can accommodate a variety of vertebral spacings, enhancing surgical flexibility and ensuring proper fit without the need for multiple spacer sizes, thus improving implantation accuracy and patient comfort.
Implementation Method 1
an actuator screw including a shaft having a proximal end and a distal portion, wherein the actuator screw further includes a head coupled to the proximal end of the shaft, wherein the distal portion of the shaft of the actuator screw is threaded and the actuator screw is at least partially disposed in the channel of the body and the threaded channel of the arm actuator, wherein, as the actuator screw is rotated using a driver tool, the arm actuator moves longitudinally relative to the body
Data Source
AI summary
An interspinous spacer includes a body having a channel and at least one slot; an arm actuator defining a threaded channel; an actuator screw including a shaft with a threaded distal portion partially disposed in the channel of the body and the threaded channel of the arm actuator; a first pin arranged to move along the slot of the body; a second pin; and first and second arms, each having a coupling extension that defines a pin opening and a curved track. The first and second arms are coupled to the body by the second pin extending through the curved tracks and further coupled to the body and the actuator arm by the first pin extending through the pin openings. The first and second arms rotate among different deployment positions according to the curved track in response to longitudinal movement of the actuator arm as the actuator screw is rotated.