Injection applicator for tissue markers
Inventors
Grinstaff, Mark W. • BLOCH, Boris Nicolas • KAPLAN, Jonah
Assignees
Boston University • Boston Medical Center Corp
Publication Number
US-12310800-B2
Publication Date
2025-05-27
Expiration Date
2033-11-21
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Abstract
The inventions provided herein relate to injection applicators, 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.
Core Innovation
The invention relates to injection applicators and tissue markers specifically designed for marking target tissue sites, such as biopsy sites in soft tissues, or for serving as cell scaffolds. The tissue markers are composed of flexible polymer matrices capable of shifting from a compact (such as rolled) configuration within a cannula to an expanded form upon deployment at the target site. Notably, these markers are engineered to have a density and electrostatic pressure substantially the same as the surrounding tissue, thereby inhibiting both fast and slow migration after implantation, without the need for adhesives.
Conventional tissue markers often suffer from deficiencies such as migration through the needle track upon needle withdrawal (fast migration) or gradual movement within tissue due to physiological motion (slow migration), resulting in poor localization for subsequent imaging or procedures. Additionally, prior markers may not be visible across multiple imaging modalities, may cause image distortion, or may degrade and lose visibility over time. There is a need for improved markers that remain in place for extended periods and are reliably detectable with standard imaging methods like MRI, X-ray, and ultrasound.
This invention addresses these challenges by providing markers that are not only flexible and expandable but also incorporate shape-memory elements, such as wires made of shape-memory alloy (e.g., nitinol), located between polymer layers. These elements facilitate transformation from a compact to an expanded shape, locking the marker in place and preventing migration. The markers may also contain imaging-visible nanoparticles (e.g., iron oxide), radiocontrast agents, or macropores to enable detection across different imaging modalities and/or to allow cellular infiltration for scaffolding functions.
Claims Coverage
The patent comprises three independent claims, each covering key inventive features related to the injection applicator, tissue marker design, and methods for preventing marker migration while ensuring imaging visibility.
Injection applicator with expandable tissue marker and shape-memory element
The injection applicator includes: - A cannula with a lumen and an open end. - An implantable tissue marker located within the lumen, which comprises a sheet with at least two layers of flexible polymer matrix and a shape-memory element between the layers. - The sheet is expandable from a rolled configuration to at least a partially unrolled configuration. - The shape-memory element is formed from a shape-memory alloy (such as a wire), and is capable of moving between a compact and an expanded configuration, facilitating expansion of the sheet. - At least one of the sheet or the shape-memory element is visible by a first imaging modality.
Injection applicator with sheet and shape-memory element expandable from compact to expanded configuration
This injection applicator comprises: - A cannula with a lumen. - A tissue marker within the lumen, comprising a sheet expandable from a compact configuration to an expanded configuration with at least one larger dimension than the compact configuration. - A shape-memory element carried within the sheet, expandable with the sheet, and comprising at least one wire of shape-memory alloy. - At least one of the sheet or shape-memory element is visible by a first imaging modality. - When inside the lumen, the sheet is rolled and the shape-memory element is compact; upon deployment, the element and sheet move towards the expanded (at least partially unrolled) configuration.
Injection applicator with biocompatible, elastic expandable sheet and shape-memory wire
The applicator includes: - A cannula with a lumen and open end. - An implantable tissue marker in the lumen composed of a biocompatible, elastic sheet (at least two layers of flexible polymer matrix) elastically expandable from a rolled compact configuration to an expanded, partially unrolled configuration. - A shape-memory element (at least one wire made of shape-memory alloy) located between the first and second surfaces in any configuration. - The expanded configuration has at least one dimension greater than the rolled compact configuration. - The elastic sheet is visible by at least one imaging modality.
In summary, the inventive features define injection applicators containing an implantable, flexible polymer-based tissue marker with a shape-memory alloy component. These features address the issues of marker migration and ensure multi-modal imaging visibility by enabling the marker to expand and conform to the target site upon deployment.
Stated Advantages
The tissue marker resists both fast and slow migration upon implantation, providing reliable long-term marking of tissue sites without the use of adhesives.
The marker is adaptable and expandable to conform to the target tissue void, enhancing physical anchorage at the implantation site.
The tissue marker can be made readily visible by at least one and optionally multiple imaging modalities, including MRI, X-ray, and ultrasound.
The marker's flexible, biocompatible polymer matrix can include macropores, allowing for tissue or cell infiltration and integration, thereby enabling use as a cell scaffold.
The invention allows for accurate identification and re-localization of biopsy or lesion sites during future procedures, potentially minimizing repeated or incorrect sampling.
The composition and structure of the marker can be tuned for durability, either to resist degradation or to biodegrade as needed.
Documented Applications
Marking a target tissue site, such as biopsy sites in soft tissues, for future reference, examination, or treatment.
Serving as a cell scaffold by facilitating cellular infiltration and tissue integration at the implantation site.
Assisting in surgical removal or targeted treatment of tissue surrounding a biopsy or lesion site by providing a precise, non-migrating marker.
Enabling imaging and localization for follow-up monitoring via MRI, X-ray, ultrasound, or combinations thereof.
Delivering active agents, such as antimicrobial agents or therapeutic compounds, to the local tissue environment.
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