Spinous Process Fixation Apparatus with Polyaxial Plates
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Solution Overview
Problem
Current spinal stabilization devices, particularly those anchored to pedicles, require significant space and muscle dissection, leading to potential nerve root injuries and limited anatomical conformity, while interspinous process devices may restrict spinal extension and reduce nerve root space, causing discomfort in patients with spinal stenosis.
Innovation Solution
An implantable device comprising first and second spaced plates configured for attachment to adjacent spinous processes, allowing polyaxial movement and adjustable connection to accommodate individual spinal anatomy, with optional use of flexible posts and collars for secure fixation and bone graft integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pedicle screws or anchoring devices are used for spinal stabilization, then stable fixation is achieved, but significant space occupation and muscle dissection are required, leading to potential nerve root injuries
Solution Approach 1:
The invention extracts the anchoring function from the pedicle region and relocates it to the spinous processes. The U-shaped configuration of the stabilization device allows it to engage with spinous processes without requiring pedicle screw insertion, thereby eliminating the harmful effects of pedicle screw placement on nerve roots while maintaining fixation stability through posterior element engagement.
Solution Approach 2:
The spinous processes serve as an intermediary structure for anchorage, replacing the pedicles as the attachment site. The U-shaped device mediates between the need for stable fixation and the avoidance of nerve root injury by distributing mechanical loads across the spinous processes rather than concentrating them in the pedicle region near nerve roots.
2Area of stationary object
If interspinous process devices are used to increase interspinous process height, then the sagittal cross-sectional area of the foramen is increased, but spinal extension is limited and patient comfort is reduced
Solution Approach 1:
The stabilization device incorporates dynamic characteristics by allowing controlled movement and adjustment. The U-shaped configuration with engagement arms enables the device to accommodate physiological spinal motions including extension, while maintaining its stabilizing function. The device adapts to the natural range of motion rather than rigidly constraining it.
3Stability of the object's composition
If spinous process plates are used for fixation, then adjacent spinous processes are stabilized, but anatomical conformity and adaptability to individual spinal anatomy are reduced
Solution Approach 1:
The stabilization device is segmented into multiple functional components including the U-shaped body and separate engagement arms. This segmentation allows each component to be optimized for specific functions while collectively providing adaptability to various anatomical configurations. The modular nature enables adjustment to different spinous process sizes and shapes.
Solution Approach 2:
Different portions of the device have specialized local characteristics - the U-shaped body provides overall structural support while the engagement arms are designed with specific geometries to match spinous process contours. This local quality differentiation enables both stable fixation and anatomical conformity simultaneously.
Data Source
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AI summary
An implantable device and method for fixation of spinous processes is presented. The device has first and second spaced plates configured for attachment to portions of adjacent spinous processes. The device can also have an implant configured for insertion between two adjacent spinous processes, but need not necessarily. The method has the steps of assembling the components of the implantable device and otherwise inserting them into position onto, between, and/or adjacent two desired spinous processes.