Interspinous Spacer with Deployable Arms for Minimally Invasive Spinal Stabilization
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Solution Overview
Problem
Current interspinous spacers for spinal stenosis treatment require larger incisions for implantation, which can lead to longer recovery times and tissue damage, necessitating the development of minimally invasive solutions that effectively open the spinal canal and relieve pain without compromising the ability to seat and stabilize spinous processes.
Innovation Solution
A spinal implant with movable arms and an actuator assembly that deploys from an undeployed to a deployed configuration, allowing for lateral stabilization and secure positioning between spinous processes, featuring a body with a clamshell construction and a spindle mechanism for rotational and translational movement, enabling minimally invasive insertion and deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional interspinous spacer is implanted, then the spinal canal is opened and pain is relieved, but the incision size is large causing tissue damage and longer recovery
Solution Approach 1:
The spacer is designed with a nested structure where the arms are contained within the body in the undeployed configuration, allowing the device to pass through a small incision. Upon deployment, the arms extend outward from the body to achieve the desired spinal canal opening effect, thus resolving the contradiction between effective treatment and minimal tissue damage.
Solution Approach 2:
The spacer transitions from a static, compact undeployed configuration to a dynamic deployed configuration where the arms move outward. This dynamic transformation allows the device to be inserted through a minimally invasive approach while still achieving the therapeutic effect of opening the spinal canal when deployed.
2Reliability
If the spacer arms are made movable to improve positioning, then lateral stabilization is enhanced, but the device complexity increases
Solution Approach 1:
The spacer is segmented into a body and multiple arms that can move independently. Each arm is equipped with a camming surface that interacts with the actuator assembly, allowing for controlled movement and positioning. This segmentation enables lateral stabilization while maintaining manageable device complexity through modular design.
Solution Approach 2:
The camming surfaces act as intermediaries between the actuator assembly and the arms. When the actuator moves, it engages the camming surfaces to translate linear motion into rotational movement of the arms, providing a simple mechanical solution for achieving complex positioning without requiring sophisticated control mechanisms.
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 implant allows for effective minimally invasive placement and stabilization between spinous processes, providing adequate distraction and pain relief while minimizing tissue disruption and facilitating quicker recovery, as it can be easily deployed and redeployed as needed.
Implementation Method 1
the at least one bearing surface contacts at least one of the caming surfaces to move both of the arms from an undeployed configuration to a deployed configuration
Implementation Method 2
a lock configured to provide resistance to keep the arms in place
Data Source
Figure 1a
Figure 1b~1e
Figure 1f
AI summary
An implantable spacer for placement between adjacent spinous processes in a spinal motion segment is provided. The spacer includes a body defining a longitudinal axis and passageway. A first arm and a second arm are connected to the body. Each arm has a pair of extensions and a saddle defining a U-shaped configuration for seating a spinous process therein. Each arm has a proximal caming surface and is capable of rotation with respect to the body. An actuator assembly is disposed inside the passageway and connected to the body. When advanced, a threaded shaft of the actuator assembly contacts the caming surfaces of arms to rotate them from an undeployed configuration to a deployed configuration. In the deployed configuration, the distracted adjacent spinous processes are seated in the U-shaped portion of the arms.