Expandable Polymeric Tissue Markers to Prevent Biopsy Site Migration
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Solution Overview
Problem
Conventional tissue markers often migrate from the target site due to negative pressure during needle withdrawal or physiological movements, leading to inaccurate image registration and biopsy site location in subsequent examinations and imaging.
Innovation Solution
Development of flexible polymeric tissue markers that adapt to the target tissue's density and electrostatic pressure, transforming from a compact to an expanded configuration upon implantation, with macropores for cellular infiltration, preventing migration and providing a scaffold for tissue integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rigid tissue markers are used, then they provide initial visibility and marking capability, but they migrate through the needle track and tissue over time due to negative pressure and physiological movements
Solution Approach 1:
The tissue marker transitions from a compressed low-profile state during implantation to an expanded stable state after deployment. The marker is compressed to fit through the needle track, then expands upon deployment to anchor securely in the tissue, preventing migration while maintaining ease of implantation.
Solution Approach 2:
The tissue marker is designed to be nested within the needle track during implantation, fitting through the confined space. After deployment, the marker expands outward from the needle track to achieve stable positioning in the tissue, effectively nesting the implantation process within the delivery device.
2Reliability
If smooth surface markers are used, then they are easy to manufacture and implant, but they cannot be securely anchored in place without adhesives
Solution Approach 1:
The tissue marker employs a curved or rounded surface geometry that facilitates secure anchoring in tissue without requiring adhesives. The curved surface allows the marker to nestle into tissue cavities and resist displacement through friction and geometric interlocking, maintaining simplicity while improving anchoring capability.
3Reliability
If bio-resorbable markers are used, then they are biocompatible and degrade over time, but they lose ultrasound visibility after about 6 months
Solution Approach 1:
The tissue marker combines bio-resorbable materials with imaging-enhancing materials to create a composite structure. The bio-resorbable component provides biocompatibility and gradual degradation, while the integrated imaging materials (such as radiopaque or ultrasound-reflective substances) maintain visibility throughout the degradation process, extending the functional monitoring period beyond 6 months.
4Measurement precision
If dense metal markers are used, then they provide strong imaging signals, but they can migrate through less dense tissue over time resulting in poor image registration
Solution Approach 1:
The tissue marker changes its physical parameters after deployment, transitioning from a compressed state during implantation to an expanded state in tissue. This parameter change includes increased volume and surface area, which improves anchoring stability and prevents migration, while maintaining imaging visibility through integrated contrast materials.
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 flexible polymeric markers securely anchor at the target site without adhesives, maintaining position for extended periods, ensuring accurate biopsy site location and facilitating tissue regeneration.
Implementation Method 1
the flexible polymeric film can adopt different configurations or forms as its surrounding volume or degree of confinement varies. For example, a flexible polymeric film can adopt a compact configuration or form, e.g., a rolled-up hollow cylinder, when it is loaded into a needle cannula. Upon ejection at a target tissue site, the polymeric film can flexibly adopt an expanded configuration or form that is sufficient to 'lock' the tissue marker in place
Implementation Method 2
a flexible polymeric tissue marker and method of using the same to mark a tissue without using an adhesive. In some embodiments, a tissue marker described herein can comprise a flexible polymeric film with at least the density and electrostatic pressure substantially the same as (i.e., similar to) the target tissue, thus preventing the tissue marker, without using an adhesive, from slow migration over time
Implementation Method 3
Imaging of a tissue with or without tissue markers can be performed using conventional imaging modalities. Examples of conventional imaging modalities include ionizing radiation imaging (e.g., x-ray imaging, computed tomography (CT), or mammography), magnetic imaging (e.g., magnetic resonance imaging (MRI)), and ultrasound imaging
Implementation Method 4
magnetic imaging (e.g., magnetic resonance imaging (MRI))
Implementation Method 5
ultrasound imaging
Data Source
AI summary
The inventions provided herein relate to tissue markers and uses thereof, e.g., to mark a target tissue site (e.g., a biopsy site in a breast tissue) or to produce a cell scaffold. The tissue markers described herein are designed to be resistant to fast migration (e.g., immediate migration after implantation through a needle track) and slow migration (e.g., over an extended period of time) upon implantation at a target tissue site (e.g., a biopsy site in a breast tissue), without using an adhesive. Additionally or alternatively, the tissue markers described herein can be readily detectable by at least one imaging modality, e.g., but not limited to magnetic resonance imaging, X-ray imaging, ultrasound imaging, or a combination thereof.