Coaxial cannula provided with a sealing element
AssigneeC. R. Bard, Inc.
InventorsNorbert F. Heske, Thomas Heske
Life of this patent
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Abstract
The invention relates to a coaxial cannula for extracting samples from tissue comprising a biopsy needle unit provided with a space for sample extraction and a sample separation unit which coaxially encompasses the biopsy needle on an external wall and is longitudinally movable. The inventive coaxial cannula comprises a sealing element which is arranged on the proximal end thereof and closes the space between the internal wall of the coaxial cannula and the external walls of the sample separation unit. The sealing element opens an air outlet when the biopsy needle unit is inserted, and prevents air intake when the biopsy needle unit is positioned and vacuum is produced in the internal chamber of the biopsy needle.
Claims15
A biopsy needle insertion aid for use with a biopsy needle of a predefined diameter, comprising:
- a cannula that is insertable in a host;
- the cannula having a lumen configured to receive therewithin the biopsy needle having the predefined outer diameter;
- the cannula having a proximal end and a distal end;
- a flexible sealing element with an opening and configured for closing a space between the lumen and the biopsy needle of the predefined diameter inserted in the opening;
- the flexible sealing element being configured such that, when the biopsy needle of the predefined diameter is inserted in the opening, air is forced in such a manner as to tend to flow between the biopsy needle and the lumen through a gap between the biopsy needle and the flexible sealing element and when an underpressure is present between the biopsy needle and the lumen, the underpressure increases a pressure force so that at least a portion of the flexible sealing element is pressed against the biopsy needle to close the gap.
A biopsy needle insertion aid for use with a biopsy needle having a predefined outer diameter, comprising:
- a cannula that is insertable in a host;
- the cannula having a lumen configured to receive therewithin the biopsy needle having the predefined outer diameter;
- the cannula having a proximal end and a distal end;
- a flexible sealing element with an opening and a sealing lip;
- the flexible sealing element being configured such that, when the biopsy needle of the predefined outer diameter is in the opening and an underpressure is present between the biopsy needle and the lumen, the underpressure increases a pressure force so that the sealing lip of the flexible sealing element is pressed against the biopsy needle to prevent an airflow past the flexible sealing element;
- and
- wherein the flexible sealing element is placed over a proximal end of the cannula and an end of the flexible sealing element has a self supporting portion that projects from the cannula beyond the end of the cannula proximal end, the sealing lip being located on the self-supporting portion.
Dependencies are inferred from the claim text.