Trocar with retractable cutting surface

• US 20060030870A1
• Filed: 08/03/2004
• Published: 02/09/2006
• Est. Priority Date: 08/03/2004
• Status: Active Grant

• Current Assignee: Rupert A. Staudner
• Original Assignee: Rupert A. Staudner
• Inventors: Staudner, Rupert A.
• Granted Patent: US 7,419,496 B2
• Time in Patent Office: Days
• US Class Current: 606/167
• CPC Class Codes: A61B 17/3496 Protecting sleeves or inner probes; Retractable tips for protecting body piercing guide needles A61M25/0612

Abstract

A trocar having a cutting shaft with a cutting surface at a distal end. The cutting shaft moves longitudinally with respect to an obturator such that in one position the cutting surface is in an exposed position suitable for application of a piercing force. Upon interruption of the piercing force to the cutting surface, the cutting surface moves longitudinally with respect to the obturator such that the cutting surface is in a retracted position within the obturator. The trocar may include a first spring urging the cutting surface to an exposed position and a second spring urging the cutting surface to a retracted position. The second spring has a slightly stronger biasing force than the first spring to bias the cutting surface to the retracted position.

Claims

1. A trocar comprising:

a. a cutting shaft with a cutting surface at a distal end;

b. a hollow obturator defining a longitudinal axis and having an open distal end, the obturator surrounding the cutting shaft and cutting surface;

c. a spring urging the cutting surface to an exposed position; and

d. a housing cooperating with the cutting shaft wherein in a first position the cutting surface is retracted within the obturator and upon rotation of the housing from the first position, the cutting surface moves with respect to the obturator to a second position wherein the cutting surface is exposed.

2. The trocar of claim 1 further comprising a flange provided on the cutting shaft that cooperates with the obturator to secure the cutting shaft from rotational movement with respect to the obturator.

3. The trocar of claim 2 further comprising a longitudinal slot provided on the obturator, wherein the slot extends from the proximal end toward the distal end.

4. The trocar of claim 3 wherein the cutting shaft flange further includes a pin extending radially outward and engaging the longitudinal slot.

5. The trocar of claim 4 further comprising a flange provided on the obturator spaced from the proximal end such that the longitudinal slot extends from the proximal end to the obturator flange.

6. The trocar of claim 1 further comprising,an outer housing, wherein the housing cooperating with the cutting shaft defines an inner housing that rotates with respect to the outer housing.

7. The trocar of claim 5 wherein the housing has a first end that contacts the obturator flange.

8. The trocar of claim 1 further comprising a radial torsion spring disposed within the housing.

9. The trocar of claim 8 wherein the torsion spring biases the cutting surface to the retracted position.

10. The trocar of claim 9 wherein the radial torsion spring has a spring force greater than a spring force of the spring urging the cutting surface to an exposed position.

11. The trocar of claim 9 wherein the radial torsion spring has a first end and a second end, wherein the first end extends inwardly.

12. The trocar of claim 11 wherein the first end of the radial torsion spring engages a longitudinal slot provided on the obturator.

13. The trocar of claim 11 further comprising a second longitudinal slot provided on the obturator, wherein the first end of the radial torsion spring engages the second longitudinal slot.

14. The trocar of claim 13 wherein the second end of the radial torsion spring extends outwardly.

15. The trocar of claim 14 wherein the inner housing includes an inner surface that comprises an aperture to receive the second end of the torsion spring.

16. The trocar of claim 4 further comprising a cam slot provided on an inner surface of the inner housing to receive the pin.

17. The trocar of claim 16 wherein the cam slot has a shape to define at least two positions such that when the pin is in a first position of the cam slot, the cutting surface is retracted within the obturator and upon rotation of the inner housing, the pin moves to a second position of the cam slot such that the cutting surface moves laterally with respect to the obturator to the exposed position.

18. The trocar of claim 17 wherein the cam slot has three positions such that when pressure against the cutting surface exists, the cutting shaft moves in a proximal direction causing the pin to move to a third position in the cam slot.

19. The trocar of claim 18 wherein when pressure against the cutting surface is removed, the pin moves to the first position in the cam slot.

20. The trocar of claim 1 wherein when the cutting surface is exposed a piercing force can be applied and upon interruption of the application of piercing force, the cutting surface automatically retracts within the obturator.

21. A method of cutting tissue comprising:

a. moving a housing on a proximal end of a obturator to expose a cutting surface from a distal end of the obturator;

b. penetrating tissue with the cutting surface by applying pressure to the tissue wherein the tissue provides resistance; and

,

c. automatically retracting the cutting surface within the distal end of the obturator in response to a decrease in tissue resistance.

22. The method of claim 21 wherein the cutting surface is automatically retracted within the obturator in response to absence of tissue resistance.

23. The method of claim 21 wherein the cutting surface is automatically retracted within the obturator when the cutting surface completely penetrates the tissue.

24. The method of claim 21 wherein the movement of the housing is a rotational movement.