Patent ID: 12232768

DETAILED DESCRIPTION

The disclosure is generally directed to a cannula having a distal region that is selectively separable from the remainder of the cannula and configured to be drawn into the interior of the cannula. During procedures where the distal region of the cannula may contact cancerous cells, the distal region may be separated and/or torn and withdrawn into the cannula to prevent the potentially contaminated distal region of the cannula from tract seeding. These and other aspects of the present disclosure are described in greater detail below.

Although the cannula and methods of using the cannula are described below with reference to a biopsy procedure, the cannula may also be used for other minimally invasive procedures, such as, for example, the cannula may be used as an access cannula during an ablation procedure.

FIGS.1-3illustrate an exemplary embodiment of a cannula10for performing a biopsy or for providing access to a surgical site. The cannula10generally includes a an elongate body portion, such as, for example, a tubular shaft14, a handle portion (not explicitly shown) coupled to a proximal end portion14aof the tubular shaft14, and first and second distal extensions16,18coupled to a distal end portion14bof the tubular shaft14. In aspects, a cannula may be provided that is devoid of the distal extensions16,18and instead has a cylindrical configuration throughout its length, such as the cannula10′ shown inFIG.4. The tubular shaft14defines a longitudinally-extending passageway20and is fabricated from any suitable material including a metal or plastic, such as, for example, silicone rubber, polyurethane, PET, thermoplastic polymers, and/or nylon. In aspects, the tubular shaft14and the first and second distal extensions16,18may be fabricated from thin, high temperature plastics, such as, for example, polyetheretherketone, polyetherimide, polysulfone, and/or polyvinylidene fluoride. As such, the distal end portion14bof the tubular shaft14may be peelable or bendable.

The distal extensions16,18of the cannula10extend distally from the distal end portion14bof the tubular shaft14. In aspects, the distal extensions16,18may be monolithically formed with the distal end portion14bof the tubular shaft14or be connected thereto in any other suitable manner, e.g., via mechanical engagement, adhesion, etc. The distal extensions16,18may each have a generally triangular configuration and define a triangular space or cutout22therebetween to assist in bending the distal extensions16,18inwardly to initiate a tear of the cannula10, as will be described. The distal extensions16,18each have a proximal end16a,18aattached to the distal end portion14bof the tubular shaft14. In aspects, the proximal end16a,18aof the distal extensions16,18may be attached to the distal end portion14bof the tubular shaft via a frangible connection24a.

The frangible connection24ahas a reduced thickness compared to a thickness of the distal end portion14bof the tubular shaft14, such that the distal extensions16,18are more likely to separate or break from the distal end portion14bat the frangible connection24a. The frangible connection24amay be a groove that extends circumferentially about the distal end portion14bof the tubular shaft14at a location where the proximal ends16a,18aof the distal extensions16,18connect to the tubular shaft14. The groove24amay be formed by scoring the tubular shaft14. In other aspects, the frangible connection24amay include perforations.

With continued reference toFIGS.1-3, the cannula10may include another frangible connection, such as, for example, a pair of second grooves24bdisposed on opposite sides of the tubular shaft14and extending parallel with a longitudinal axis defined by the tubular shaft14. The grooves24bare disposed between the proximal end16aof the first distal extension16and the proximal end18aof the second distal extension18and bisect the tubular shaft14into two longitudinal half-sections27,29. The grooves24bmay extend a length of at least about 3-6 cm, and in aspects about 4 cm, proximally from a distal-most end of the tubular shaft14. The grooves24bmay be formed by having a reduced thickness at the location of the grooves24bor by scoring to facilitate tearing or peeling of the two longitudinal half-sections27,29of the tubular shaft14about the grooves24b. In other aspects, first and second strips of weaker material may be used to attach the two longitudinal sections27,29of the tubular shaft14.

The cannula10further includes first and second tethers26,28. The first and second tethers26,28are coupled to the respective distal ends16b,18bof the first and second distal extensions16,18. In aspects, only one tether26or28may be provided that couples to both of the first and second distal extensions16,18. The tethers26,28extend proximally through the cannula10and terminate in a proximal end (not explicitly shown) that may be manipulated by a clinician.

In some aspects, the distal extensions16,18may be slidably coupled to the distal end portion14b, such that the distal extensions16,18may be axially translated between extended and retracted states.

In operation, the cannula10may be inserted through a natural or artificial tissue opening and guided to a target tissue site. In some aspects, the cannula10may be passed through a working channel of an endoscope or other access-providing device and/or may be guided along a stylet to the surgical site. The distal extensions16,18of the cannula10are positioned within or adjacent a tumor and are used to either gather a sample of the tumor or to guide another surgical instrument (e.g., an electrosurgical instrument) to the tumor.

After using the cannula10, but prior to withdrawing the cannula10from the surgical site, a proximally-oriented force is applied to the tethers26,28sufficient to break, bend, peel, or tear the distal extensions16,18from the tubular shaft14at the first groove24a. During breaking or bending, the distal ends16b,18bof the distal extensions16,18pivot inwardly toward one another about the groove24a. A further proximally-oriented force exerted on the tethers26,28folds the distal ends16b,18bof the distal extensions16,18inwardly and proximally while also tearing or peeling the distal end portion14bof the tubular shaft14about the second grooves24b, thereby everting the distal extensions16,18and the distal end portion14bof the tubular shaft within the passageway20of the tubular shaft14. In this way, a generally distal region of the cannula10is turned inside out.

With the distal extensions16,18and the distal end portion14bof the tubular shaft14folded inside out, the cannula10may be withdrawn from the surgical site. Since the distal extensions16,18and/or distal end portion14bof the tubular shaft14are the only portions of the cannula10to have potentially made contact with the tumor and now have their outer surfaces inside of the tubular shaft14, withdrawal of the cannula10from the surgical site will not pose any risk of tract seeding.

FIGS.5and6illustrate additional embodiments of a cannula110and210, similar to the cannula10ofFIGS.1-4. The cannula110has three longitudinal sections116,118,120formed by three vertically-extending grooves124, and three tethers126attached to respective distal ends of the longitudinal sections116,118,120. The cannula210has four longitudinal sections216,218,220,22formed by four vertically-extending grooves224, and four tethers226attached to respective distal ends of the longitudinal sections216,218,220,22.

It is contemplated that the cannula disclosed herein may have any suitable number of longitudinal sections and grooves for facilitating separation of the longitudinal sections.

It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques).