Trocar with lockable shield

• US 5,607,440 A
• Filed: 06/02/1995
• Issued: 03/04/1997
• Est. Priority Date: 05/06/1994
• Status: Expired due to Term

• Current Assignee: Sherwood Services AG
• Original Assignee: Endoscopic Concepts, Inc.
• Inventors: Johnson, Thomas R., Danks, John K., Mazzola, Richard V.
• Primary Examiner(s): DAWSON, GLENN K
• Application Number:
  US08/459,331
• Time in Patent Office: 641 Days
• Field of Search: 604/164, 604/171, 604/264, 604/165, 606/184, 606/185, 606/167
• US Class Current: 606/185
• 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 17/3474 Insufflating needles, e.g. Veress needles
• CPC Class Codes: A61B 17/3496 Protecting sleeves or inner probes; Retractable tips for protecting body piercing guide needles A61M25/0612
• CPC Class Codes: A61B 17/3498 Valves therefor, e.g. flapper valves, slide valves haemostasis valves A61M39/06; check valves A61M39/24
• CPC Class Codes: A61B 2017/0023 disposable
• CPC Class Codes: A61B 2017/0084 low friction A61B2017/00853 takes precedence
• CPC Class Codes: A61B 2017/346 with wings
• CPC Class Codes: A61B 2017/349 Trocar with thread on outside

Abstract

A trocar is formed from a cannula and an interfitting obturator for penetrating body cavity walls in laparoscopic and endoscopic surgery. The obturator is provided with an improved piercing tip having a pointed blade and an improved double locking blunt nosed shield design. Hydrophilic coatings or components are also employed on the shield and cannula to facilitate quicker shield action covering the pointed blade and ease of entry of the cannula tube through the body cavity wall. The cannula also has an improved inexpensive flexible flapper valve and can be manufactured with a reusable cannula tube but disposable flapper valve assembly to minimize cost. The shield locks in a partially retracted position whereby the point of the blade is covered, but sharp lateral portions are exposed.

Claims

1. A shielded obturator comprising:

(a) an obturator sheath having a distal end and a proximate end;

(b) a handle mounted to the proximate end of said obturator sheath;

(c) a pointed blade on the distal end of the obturator sheath said pointed blade having a sharpened point at a distal end and sharpened lateral portions;

(d) a shield slidably mounted to the obturator sheath and movable relative to the pointed blade between an extended protective position, a partially retracted semi-protective position covering the sharpened point of the pointed blade while leaving at least a portion of the sharpened lateral portions exposed for cutting tissue, and a retracted unprotected position; and

(e) a biasing means tending to bias the shield into the extended protective position.

2. The shielded obturator of claim 1 further comprising a latch means engaging with said shield and permitting the shield to be locked in both the extended protective position, and the partially retracted semi-protective position.

3. The shielded obturator of claim 2 wherein the latch means is actuatable to allow the shield to slide from its extended protective position towards its retracted unprotected position when force is applied to said shield.

4. The shielded obturator of claim 3 wherein said shield has a distal end to cover the pointed blade and a proximate end, and said latch means is comprised of a blocking member, and a plurality of longitudinally spaced detents on the proximate end of the shield which said blocking member may engage to prevent the shield from retracting.

5. The shielded obturator of claim 1 wherein said shield has a distal end to cover the pointed blade and a proximate end, and said distal end is provided with a hydrophillic coating.

6. The shielded obturator of claim 1 wherein the pointed blade is substantially planar, wherein said sharpened lateral portions comprise a first sharpened edge proceeding from the sharpened point to a first shoulder, and a second sharpened edge proceeding opposite the first sharpened edge to a second shoulder.

7. The shielded obturator of claim 6 wherein the shield is of cylindrical shape and is slidable mounted within the obturator sheath, said shield having a proximal end received within the obturator handle, and a distal end having a channel of sufficient depth and width to receive the pointed blade within said distal end of the shield.

8. The shielded obturator of claim 7 in which the distal end of the shield has a blunt end and proceeds along a concave curve to a shoulder portion, said shoulder portion being of substantially the same width as an interior of the obturator sheath.

9. The shielded obturator of claim 8 wherein the blunt end of the shield covers the sharpened point when said shield is positioned in the partially retracted semi-protective position, yet the concave curve of the distal end of the shield permits the first and second sharpened edges of the pointed blade adjacent to the shoulders of the pointed blade to remain exposed.

10. The shielded obturator of claim 7 wherein the distal end of the shield is provided with a hydrophillic coating.

11. A trocar comprising:

(a) a cannula with a housing and a cannula tube, the canula tube having a lumen of sufficient diameter to receive an obturator sheath;

(b) a shielded obturator having a handle, an obturator sheath interfitting in the lumen of the cannula tube and having a proximal end joined to said handle and also having a distal end to which a pointed blade is mounted the pointed blade including a sharpened point and sharpened lateral portions;

(c) a shield slidably mounted interiorly of the obturator sheath and moveable relative to the pointed blade between an extended protective position, a partially extended semi-protective position, and a retracted unprotected position covering the point while leaving at least a portion of the sharpened lateral portions exposed for cutting tissue; and

(d) a biasing means tending to bias the shield into the extended protective position.

12. The trocar of claim 11 further comprising a latch means engaging with said shield and permitting the shield to be locked in the extended protective position and the partially extended semi-protective position.

13. The trocar of claim 11 in which the pointed blade is substantially planar;

said sharpened lateral portions comprising a first sharpened edge proceeding from the point to a shoulder, and a second sharpened edge proceeding opposite the first sharpened edge to a second shoulder.

14. The trocar of claim 13 wherein said shield has a distal shield end to cover the pointed blade and a proximate shield end, and the latch means is comprised of a blocking member, and a plurality of longitudinally spaced detents on the proximate shield end which said blocking member may engage to prevent the shield from retracting.

15. The trocar of claim 13 in which the shield is of generally cylindrical shape, said shield having a proximal end received within the obturator handle, and a blunt distal end having a channel of sufficient depth and width to receive the pointed blade within the distal end of the shield.

16. The trocar of claim 15 in which the distal end of the shield proceeds along a concave curve to a shoulder portion, said shoulder portion being of substantially the same width as an interior of the obturator sheath.

17. The trocar of claim 16 wherein the blunt distal end of the shield covers the point when said shield is positioned in the partially retracted semi-protective position, yet the concave curve of the blunt distal end of the shield permits the first and second sharpened edges of the pointed blade adjacent to the shoulders of the pointed blade to remain exposed.

18. The trocar of claim 15 wherein the distal end of the shield is provided with a hydrophillic coating.

19. The trocar of claim 11 wherein said shield has a distal end to cover the pointed blade and a proximate end, and said distal end is provided with a hydrophillic coating.

20. A method of using a trocar to penetrate a body wall comprising the steps of:

i) providing a trocar having;

(a) a cannula with a housing and a cannula tube containing a lumen of sufficient diameter to receive an obturator sheath;

(b) a shielded obturator having a handle, an obturator sheath interfitting with the lumen of the cannula tube, said obturator sheath having a proximate end connected to said handle and a distal end, and a pointed blade with a sharpened tip mounted in the distal end of the obturator sheath;

(c) a shield slidably mounted adjacent to the obturator sheath and moveable relative to the pointed blade between an extended position covering the pointed blade, a partially retracted semi-protective position at least partially covering the pointed blade, and a retracted position;

(d) a biasing means tending to bias the shield into said extended position;

(e) a latch means having at least two locked positions in which the shield is locked in either the extended position or the partially retracted semi-protective position, and having an actuated position which permits the shield to be forced into its retracted position;

ii) actuating said latch means;

iii) urging said cannula tube and pointed blade against the body wall to be penetrated, whereby said shield is pushed into said retracted position by the body wall to expose said pointed blade to penetrate the body wall and said latch means is biased to automatically resume a locking position upon return of the shield to either said partially retracted semi-protective position or said extended protective position;

iv) urging said cannula tube and pointed blade against the body wall until the sharpened tip penetrates the body wall and the shield locks in the partially retracted semi-protective position;

v) urging said cannula tube and pointed blade against the body wall until the pointed blade has completely penetrated the body wall and the shield locks in the extended protective position;

vi) urging said cannula tube against the body wall until the lumen of the cannula tube communicates through the body wall.