Radiopaque tissue marker
Inventors
Baker, Justin Jeffrey • Gingras, Peter Hayes • Priest, Robert • Derwin, Kathe • Iannotti, Joseph P. • Sahoo, Sambit • Baker, Andrew Ryan
Assignees
Viscus Biologics LLC • Cleveland Clinic Foundation
Publication Number
US-11413112-B2
Publication Date
2022-08-16
Expiration Date
2038-10-15
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Abstract
A fiber-based radiopaque tissue marker for radiographic marking of tissue is provided. The marker is a sterile, single-patient-use polymeric fiber with a radiopaque material and a dye. The marker is radiopaque using standard radiographs such as x-rays and mammography. The marker can also be visualized by low-dose CT scans.
Core Innovation
The invention provides a fiber-based radiopaque tissue marker designed for radiographic marking of tissue, composed of a sterile, single-patient-use polymeric fiber infused with a radiopaque material and a dye or colorant. This marker is visible using standard radiographic imaging methods such as x-ray, mammography, and low-dose computed tomography (CT) scans. The fiber possesses mechanical properties including a diameter approximately between 300 and 400 microns, tensile strength exceeding 20 newtons, knot strength also greater than 20 newtons, and elongation at rupture under 50%, which collectively afford it the ability to be securely knotted and positioned in tissue without migration.
The radiopaque tissue marker addresses the problem in oncology where traditional tissue markers used for marking biopsy or lumpectomy sites have limited visibility in radiographic imaging, are prone to migration, possess insufficient mechanical strength, and cannot easily be placed using standard surgical knots. Furthermore, existing markers tend to obscure surrounding tissue radiographically, cause tissue deformation due to their size and stiffness, and can lead to patient discomfort. Importantly, precise marking is critical for accurate guided radiation therapy and surgical procedures, especially for tissues with irregular shapes where continuous outlining of regions of interest is necessary.
This radiopaque tissue marker enables improved imaging and secure placement by allowing it to be passed through tissue and tied with multiple surgeon's knot throws, thus preventing migration. It combines clinically relevant radiopacity with high tensile and knot strength, permitting permanent or temporary attachment to soft or hard tissues through open, percutaneous, or endoscopic procedures. The fiber's monofilament construction, choice of polymeric material (such as polypropylene), and incorporation of radiopaque material (such as barium sulfate at 40% or more by weight) and dye enhance radiographic visibility while minimizing tissue reaction and discomfort.
Claims Coverage
The patent includes multiple independent claims focusing on the design and functional properties of a non-biodegradable radiopaque marker composed of specific materials and configured for secure tissue marking and radiographic visibility.
Non-biodegradable elongate flexible polymer monofilament with radiopaque material
The marker comprises a non-biodegradable elongate flexible polymer monofilament made of polypropylene with a radiopaque material disposed within it to provide radiopacity.
Fiber dimension and tensile properties
The monofilament has a circular cross-section with a diameter from 300 microns to 400 microns and possesses a tensile strength greater than 20 Newtons.
Radiographic visibility under low energy imaging
The radiopaque marker is configured to be clearly visible under radiographic imaging performed at 120 kV or less, including standard x-rays and mammography.
Capability to be knotted and form continuous markings on tissue
Portions of the monofilament are configured to be knotted and attached securely to tissue with knots having tensile strengths around 20 N to prevent movement, and other portions can be disposed along tissue surfaces to form continuous radiopaque markings.
Inclusion of dye or colorant for enhanced visibility
The marker includes a dye or colorant within the monofilament to enhance visibility, configured to impart a blue color.
The independent claims collectively cover a non-biodegradable polypropylene monofilament radiopaque tissue marker characterized by specified diameter, tensile strength, knotting capability, radiopacity including radiopaque material content of 40% or more barium sulfate, enhanced visibility via dye, and suitability for secure tissue marking and radiographic imaging under low-dose conditions.
Stated Advantages
Provides favorable radiopacity compatible with standard radiographs and low-dose CT scans, ensuring clear imaging of tissue markers.
Exhibits high tensile strength and knot strength to allow secure placement in tissue and prevent migration, improving accuracy of tissue marking.
Flexible, low profile, and small diameter design minimizes tissue distortion and patient discomfort compared to metallic markers.
Can be used to outline irregularly shaped tissue regions continuously due to fiber flexibility and length, aiding guided radiation therapy and imaging.
Enables quick, reliable, and inexpensive placement using standard surgical techniques and knot tying.
Avoids radiographic obscuring or bloom effect seen in existing larger or metallic markers, allowing unobstructed tissue visualization.
Potentially reduces treatment costs and improves treatment outcomes by facilitating accurate localization for accelerated partial breast irradiation (APBI).
Suitable for use in a variety of tissue types and access methods including open, percutaneous, or endoscopic procedures.
Documented Applications
Marking biopsy sites or lumpectomy sites in oncology for subsequent non-invasive imaging to identify tissue of interest.
Use in image-guided radiation therapy by enabling precise outlining of tissue regions to improve radiation delivery accuracy.
Placement in both soft tissue and hard tissue sites to secure and mark tissue localization during surgical procedures.
Incorporation into high volume tissue fillers used to fill tissue cavities such as breast lumpectomy cavities to maintain breast shape and facilitate radiographic visualization.
Integration into surgical meshes like hernia mesh to mark borders and centers for radiographic visualization, enabling fluoroscopic placement and post-operative tracking.
Use as a non-resorbable or resorbable implantable marker, with resorbable versions designed to dissolve over months or years after implantation.
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