Trocar for inserting implants

• US 20020188247A1
• Filed: 07/08/2002
• Published: 12/12/2002
• Est. Priority Date: 04/23/1998
• Status: Active Grant

• Current Assignee: Intarcia Therapeutics, Inc.
• Original Assignee: Intarcia Therapeutics, Inc.
• Inventors: Peery, John R.
• Granted Patent: US 7,329,242 B2
• Time in Patent Office: Days
• US Class Current: 604/60
• CPC Class Codes: A61B 17/3417 Details of tips or shafts, e.g. grooves, expandable, bendable; Multiple coaxial sliding cannulas, e.g. for dilating syringe needles A61M5/32; dilators A61M29/00
• CPC Class Codes: A61B 17/3468 for implanting or removing devices, e.g. prostheses, implants, seeds, wires devices for implanting seeds A61M37/0069
• CPC Class Codes: A61M 2205/195 by the needle tip shape
• CPC Class Codes: A61M 37/0069 Devices for implanting pellets, e.g. markers or solid medicaments for introducing of radioactive sources for interstitial radiation therapy, i.e. brachytherapy A61N5/1027
• CPC Class Codes: A61M 5/3286 Needle tip design, e.g. for improved penetration

Abstract

An implant retention trocar includes a cannula for puncturing the skin of an animal and an obturator for delivering the implant beneath the skin of the animal. The implant retention trocar has a cannula distal tip design which causes a minimum of trauma and tearing of tissue during implant insertion. A spring element received within the cannula prevents an implant which is to be inserted into an animal from falling out of the cannula during the implant insertion process. The spring element includes a longitudinal leg which is folded with a zig-zag shaped bend. When the spring element is inserted into the cannula the zig-zag shaped bend of the longitudinal leg retains the implant within the cannula.

Claims

1. A trocar comprising:

a cannula for receiving an implant and inserting the implant into an animal;

a spring element received within the cannula, the spring element having a leaf spring for retaining the implant inside the cannula, the leaf spring applying a frictional force against the implant sufficient to prevent the implant from sliding out of the cannula under a weight of the implant; and

an obturator for delivering the implant from the cannula into the animal.

2. The trocar according to claim 1, wherein the spring element includes a plate which is cut to form the leaf spring.

3. The trocar according to claim 1, wherein the leaf spring is formed as a T-shaped cut out portion.

4. The trocar according to claim 1, wherein the leaf spring has a plurality of successive bends and the successive bends are arranged to alternately contact an inside wall of the cannula and an outside of the implant to retain the implant in the cannula.

5. The trocar according to claim 4, wherein the leaf spring has a longitudinal leg arranged substantially parallel to an axis of the cannula and a cross leg substantially perpendicular to the longitudinal leg, and the plurality of successive bends are formed on the longitudinal leg.

6. The trocar according to claim 4, wherein the leaf spring having the plurality of successive bends is compressed in a radial direction of the cannula by the insertion of the implant into the cannula.

7. The trocar according to claim 1, wherein the obturator has a tapered distal end to prevent ejection of the spring element from the cannula when the obturator is moved distally to eject the implant from the cannula.

8. The trocar according to claim 1, wherein the spring element is fixed within the cannula.

9. A trocar comprising:

a substantially cylindrical cannula body;

a distal end of the cannula body having a leading edge formed by a first plane which is at a first angle with respect to a longitudinal axis of the cannula body, and a trailing edge formed by a second plane which is at a second angle with respect to the longitudinal axis of the cannula body; and

wherein the first angle of the leading edge is larger than the second angle of the trailing edge.

10. The trocar according to claim 9, wherein a transition between the first plane and the second plane is gradual.

11. The trocar according to claim 9, wherein the trailing edge of the cannula body distal end is radiused to prevent coring or tearing of tissue.

12. The trocar according to claim 9, wherein the first angle is about 20-35 degrees and the second angle is about 10-25 degrees.

13. The trocar according to claim 9, wherein a difference between the first angle and the second angle is about 2-20 degrees.

14. The trocar according to claim 9, wherein the leading edge of the cannula distal end has a reverse grind extending along between 25 and 75 percent of an exterior circumference of the cannula.

15. The trocar according to claim 14, wherein the reverse grind is a surface which intersects an interior surface of the cannula and an exterior surface of the cannula.

16. The trocar according to claim 15, wherein a distal most tip of the cannula is located at the intersection of the interior surface and the reverse grind.

17. The trocar according to claim 9, wherein the cannula body includes a leaf spring fixed within the cannula body for retaining an implant.

18. A method of implanting an implant in an animal comprising:

positioning an implant at a preferred location within a cannula with a forward end of the implant located between about ⅓ and

⅔

of the way between a leading edge of the cannula and a trailing edge of the cannula;

holding the implant at approximately the preferred location while inserting the cannula into the animal; and

delivering the implant from the cannula into the animal.