Expandable Interspinous Fixation Device with Adjustable Plates
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Solution Overview
Problem
Current interspinous fixation devices for spinal fusion lack the ability to accommodate varying patient anatomies and often expose patients to radiation during placement, with limited integration of graft material for bone growth and potential injury risks from screw placement near nerve roots and vasculature.
Innovation Solution
An expandable interspinous fixation device with adjustable plates and a mechanical actuator allows for customizable length adjustment, incorporating inner expansion portions that slide relative to an outer fixed portion, enabling precise fitting to the patient's anatomy and integration of graft material for bone fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed-size interspinous devices are used, then device simplicity is maintained, but anatomical adaptability is limited
Solution Approach 1:
The device incorporates expandable plates with inner expansion portions that can slide relative to outer fixed portions, allowing the device to dynamically adjust its size to match various patient anatomies. This dynamic adjustment capability enables a single device design to accommodate different anatomical configurations without requiring multiple fixed-size device variants.
Solution Approach 2:
The plates are divided into multiple sub-portions including outer fixed portions and inner expansion portions. This segmentation allows independent movement of the inner portions relative to the outer portions, enabling controlled expansion and adjustment of the device dimensions while maintaining structural integrity through the segmented architecture.
2Reliability
If pedicle screw-rod systems are used, then segmental stability is achieved, but patient injury risk increases due to proximity to nerve roots and vasculature
Solution Approach 1:
The invention extracts the fixation function from the dangerous pedicle screw-rod system and relocates it to the interspinous process region. By placing fixation elements on the spinous processes rather than penetrating near nerve roots and vasculature, the device achieves segmental stability while eliminating the harmful proximity to critical neural and vascular structures.
Solution Approach 2:
The interspinous device acts as an intermediary fixation method between the vertebral bodies, using the spinous processes as anchor points. This intermediary approach provides adequate stabilization for spinal fusion without requiring direct attachment to the vertebral bodies where nerves and vessels are located, thus reducing injury risk while maintaining fixation reliability.
3Ease of manufacture
If traditional interspinous devices are used, then minimally invasive approach is maintained, but graft material integration is limited
Solution Approach 1:
The device merges the fixation function with the graft material integration function into a single unified structure. The expandable plates and fixation elements are designed to incorporate and hold graft material within the interspinous space, combining two previously separate functions (fixation and graft delivery) into one integrated device system.
Solution Approach 2:
The device serves multiple functions simultaneously: it provides structural fixation through the expandable plates on the spinous processes, enables graft material integration within its structure, and maintains minimally invasive implantation. This multi-functionality allows a single device to address multiple surgical requirements without requiring additional separate components or procedures.
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 device provides a minimally invasive solution with reduced risk of patient injury, improved anatomical fit, and enhanced bone fusion capabilities, offering equal or greater biomechanical stability compared to traditional pedicle screw systems while minimizing radiation exposure.
Implementation Method 1
first and second inner expansion portions that slide (along or parallel to the longitudinal axis through each plate) on the outer fixed portion
Implementation Method 2
a mechanical actuator for increasing or reducing the length of the device
Implementation Method 3
at least a portion of an inner surface of each of the first plate and second plate having a plurality of studs, and adjusting the length of each of the first and second plates such that at least a portion of each of the two adjacent vertebrae are clamped between the plurality of studs
Data Source
AI summary
A device and method for performing interspinous fixation or spinal fusion is provided. The device may generally include a first plate and a second plate, each having an adjustable length, and a mechanical actuator for increasing or reducing the length of the plates and, correspondingly, the device. Operation of the mechanical actuator causes first and second inner expansion portions of each plate to simultaneously slide on an outer fixed portion of the plate, to increase or decrease (depending on the direction of operation of the mechanical actuator) the separation between the first and second inner expansion portions, and thus, lengthen or shorten the plates and device.