Expandable Device for Epidural Tissue Differentiation
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Solution Overview
Problem
Current needle insertion techniques for Epidural anesthesia, such as the 'loss of resistance technique,' are prone to inaccuracies and risks due to the elastic properties of tissues like the Ligamentum Flavum, leading to potential puncture of the Dura mater and complications like post-dural puncture headaches.
Innovation Solution
An anatomical-positioning apparatus with an expandable device, such as a balloon, securely attached to a cannula, which exerts pressure on tissues to determine their type and transition points, using sensors to measure mechanical responses and facilitate controlled advancement to prevent tissue puncture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the loss of resistance technique is used to advance the needle through tissues, then the needle can reach the Epidural space, but the elastic properties of the Ligamentum Flavum cause fiber stretching and potential rupture deep inside the Epidural space, increasing the risk of overshooting the needle tip into the Dura mater
Solution Approach 1:
The expandable device is deployed in advance of the needle tip to pre-expand the tissue ahead of the needle path. This preliminary expansion creates a safer pathway by reducing the elastic recoil effect that causes fiber stretching and rupture, allowing the needle to advance more predictably without overshooting the Epidural space boundary.
Solution Approach 2:
The expandable device acts as an intermediary element between the needle and the tissue. By expanding ahead of the needle tip, it modifies the mechanical properties of the tissue pathway, reducing elasticity and providing a more stable, predictable advancement path that prevents harmful overshooting into the Dura mater.
2Ease of operation
If the needle is advanced through dense Ligament layers using tactile feedback, then the physician can detect resistance changes, but the resolution of non-controlled advancement increments is very limited and differs extensively from one physician to another
Solution Approach 1:
The system incorporates sensors that provide real-time feedback on tissue resistance, expandable device expansion force, and needle advancement position. This objective feedback mechanism replaces subjective tactile feedback, providing consistent, measurable data that enables precise control of advancement increments with high resolution, eliminating inter-physician variability.
Solution Approach 2:
The patent replaces the mechanical tactile feedback system with sensor-based detection systems. These sensors measure physical parameters such as force, pressure, or displacement with high precision, converting subjective tactile information into objective, quantifiable data that improves advancement control resolution and consistency.
3Reliability
If the loss of resistance technique is used with a fluid-filled syringe, then the physician can detect loss of resistance when entering the Epidural space, but there is a relatively high risk of false loss of resistance taking place inside the Ligamentum Flavum due to a small space between adjacent fibers
Solution Approach 1:
The expandable device serves as an intermediary that actively engages with the tissue ahead of the needle tip. By measuring the force required to expand the device against tissue resistance, the system obtains a more reliable and specific measurement of tissue mechanical properties, reducing the likelihood of false positives that occur with passive fluid injection methods.
Solution Approach 2:
The system changes the measurement parameter from pressure differential (loss of resistance) to direct force or displacement measurement during expansion. This parameter change provides more specific and reliable tissue characterization, as the expandable device's interaction with tissue mechanics is less prone to false readings caused by small inter-fiber spaces in the Ligamentum Flavum.
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 apparatus provides precise tissue differentiation and controlled advancement, reducing the risk of puncturing the Dura mater and improving the safety and accuracy of needle placement during Epidural anesthesia procedures.
Implementation Method 1
the expandable device exerts pressure onto portions of the mammalian tissue to displace the mammalian tissue from an undistorted position
Implementation Method 2
the elastic properties of the LF 60, the elastic fibers are pushed by the needle and are stretched into the ES 70
Data Source
Figure 1~3
Figure 2a~2d
Figure 4a~4c
AI summary
An anatomical-positioning apparatus for acquiring mechanical data from a tissue to facilitate determining type of the tissue and transition between different tissues and cavities. The anatomical-positioning apparatus includes a cannula, having a tip, an expandable device having a contracted form size and an expanded form size, wherein the expanded form size is substantially larger than the contracted form size. The anatomical-positioning apparatus further includes an introducer, having a longitudinal axis and a distal end, facilitating the introduction of the expandable device into the tissue, the expandable device being in a contracted state, an expanding-mechanism for expanding and contracting the expandable device, and a sensor for measuring physical parameters associated with the expandable device. An aspect of the present invention is to provide a method for acquiring mechanical data from a tissue by an expandable device, while the expandable device exerts pressure onto portions of the tissue.