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WO1997032530A1 - Canule pour un systeme de trocart - Google Patents

Canule pour un systeme de trocart Download PDF

Info

Publication number
WO1997032530A1
WO1997032530A1 PCT/GB1996/000521 GB9600521W WO9732530A1 WO 1997032530 A1 WO1997032530 A1 WO 1997032530A1 GB 9600521 W GB9600521 W GB 9600521W WO 9732530 A1 WO9732530 A1 WO 9732530A1
Authority
WO
WIPO (PCT)
Prior art keywords
guard
cannula
slot
tail section
trocar
Prior art date
Application number
PCT/GB1996/000521
Other languages
English (en)
Inventor
Nicholas Richard Kemp
Original Assignee
Microsurgical Equipment Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Microsurgical Equipment Ltd. filed Critical Microsurgical Equipment Ltd.
Priority to PCT/GB1996/000521 priority Critical patent/WO1997032530A1/fr
Publication of WO1997032530A1 publication Critical patent/WO1997032530A1/fr

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/34—Trocars; Puncturing needles
    • A61B17/3494—Trocars; Puncturing needles with safety means for protection against accidental cutting or pricking, e.g. limiting insertion depth, pressure sensors
    • A61B17/3496—Protecting sleeves or inner probes; Retractable tips

Definitions

  • the present invention relates to the cannula of a trocar system.
  • a trocar is a medical cutting tool used in laparoscopy.
  • laparoscopy a hollow tube or cannula is inserted through the wall of the abdominal cavity of a patient to allow surgical tools to be used within the abdominal cavity.
  • the tools are inserted and withdrawn through the cannula. Any surplus tissue or organ can be withdrawn from the cavity through the cannula.
  • One or more cannulae can be inserted through the abdominal wall according to requirements.
  • a known trocar is in the form of an elongate shaft supporting at its free end, a head of circular cross-section, which is profiled at its free end portion to form a solid three or four sided pyramid defining three or four cutting edges leading away from the tip.
  • the shaft and head are encased in a retractable guard of plastics material.
  • the guard can be displaced longitudinally of the shaft to expose the head but is spring biased so as to envelop the head once any displacement forced is removed.
  • the trocar is inserted into the cannula until its free and projects from the forward end. The cannula and trocar are then urged against the abdominal wall.
  • the resistance of the wall acts to displace the guard and so exposes the cutting edges.
  • the head pierces and cuts the abdominal wall until it emerges from the other side of the wall whereupon, with the resistance of the wall removed, the guard is resiliently displaced once again to cover the head so that the head is prevented from damaging any organs within the abdominal cavity. Continued penetration will allow the cannula to enter the abdominal cavity.
  • the guard system on the trocar and the surrounding cannula mean that the size of opening which can be cut in the abdominal wall is very much smaller than the size of the opening needed to accommodate the cannula. Thus, when the cannula is forced through the opening but by the trocar, the opening is stretched and there is a very real danger of the tissue of the abdominal wall tearing or being otherwise damaged.
  • a cannula for a trocar system comprising a tubular elongate tail section extending from an enlarged head section, the enlarged head section defining a cavity to receive the handle of a trocar when the cutting head of the trocar is inserted via the cavity into the tail section, the tail section including a guard which is telescopically supported by the tail section for movement between a first position in which it covers the head of the trocar and a second position in which it exposes the head of the trocar, and locking mechanism which automatically tends to lock the guard in the first position whenever the guard reaches the first position.
  • Figure 1 is a plan view of the system with the trocar inserted in the cannula, with the cannula guard extended;
  • Figure 2 is a view similar to that of Figure 1 but with the cannula guard retracted;
  • Figure 3 is a fragmentary sectional view, to an enlarged scale, through the system showing the operating mechanism for the cannula guard;
  • Figure 4 is a fragmentary sectional view of the distal end portion of the cannula with the guard extended;
  • Figures 5a to 5c are plan views of the system with parts cut away showing the cannula guard in three different positions.
  • the cannula and trocar system to be described comprises a cannula 2 having an enlarged body section 4 with an elongate tubular tail section 6 extending therefrom.
  • the distal end portion of the tail section 6 houses a retractable guard 8.
  • the trocar 10 has a handle portion 12 which projects from the body section 4 of the cannula 2 and an elongate shaft 5 extending from the handle portion 12.
  • a cutting head 14 is supported at the distal end of the shaft 5.
  • the enlarged body section 4 has a cylindrical cavity 28 arranged partially to accommodate the handle portion 12 of the trocar.
  • a channel of circular cross-section leading from the cavity 28 accommodates an end portion of the tail section 6 and the tail section 6 is rigidly secured to the body section 4 at this point.
  • the retractable guard 8 consists of a sleeve 20 telescopically supported within the tail section 6 and terminating at its distal end with an enlarged collar 22 having an outside diameter substantially equal to the outside diameter of the tail section. At its other end the sleeve 20 is slidably supported on a hollow stub shaft 26.
  • the stub shaft 26 has an enlarged end portion 26A which has an outside diameter equal to the inside diameter of the tail section and is rigidly secured to the tail section 6 at a location adjacent the cavity 28.
  • the outside diameter of the remainder of the stub shaft 26 has a diameter just less than the inside diameter of the sleeve 20.
  • a coil spring 30 is located in the annular channel and extends around the stub shaft 26. One end of the coil spring is secured to the enlarged end portion 26A of the stub shaft while the other end is secured to the adjacent end portion 20A of the sleeve 20 (see Figure 3).
  • the spring 30 acts to urge the adjacent end 20A of the sleeve 20 away from the enlarged end portion 26A of the stub shaft 26.
  • a pin 32 projects radially outwardly from the end portion 20A of the sleeve 20 and engages an L-shaped slot 34 in the tail portion 6.
  • the engagement of the pin 32 in the slot 34 thus limits the degree of relative movement between the sleeve 20 and the tail section 6.
  • One slot portion 34A of the L-shaped slot 34 extends axially of the tail section 6 while the other slot portion 34B extends circumferentially of the tail section 6.
  • the coil spring 30 When the coil spring 30 is fitted, it is fitted in a manner to urge the sleeve 20 to rotate in an anti ⁇ clockwise sense (when viewed from its distal end) so that when the pin 32 engages the slot portion 34B of the slot, it is displaced away from the other slot portion 34A (see Figure 5a) .
  • the length of the slot portion 34A is equal to the distance that the guard can travel between its extended and retraced positions.
  • the pin 32 lies in the slot portion 34A at a location remote from the slot portion 34B (see Figure 5c) .
  • the pin 32 is moved to a location at the junction of the two slot portions 34A, 34B (see Figure 5b) .
  • the pin 32 In operation with the guard initially extended, the pin 32 lies in the slot portion 34B and is urged in an anti-clockwise sense away from the slot portion 34A.
  • the guard is thus locked against longitudinal displacement relative to the cannula.
  • the pressure of the guard against the wall will stop it rotating with the cannula and so the pin 32 will move into the slot 34A (see Figure 5B) .
  • Continued an increasing pressure against the abdominal wall will start to retract the guard 8 and allow the trocar to incise the wall itself.
  • the pin 32 will thus move along the slot portion 34A to a position remote from the slot portion 34B (see Figure 5C) .
  • the pressure on the guard will be released and the coil spring will urge the guard back along the slot portion 34A and then into the slot portion 34B.
  • the guard 8 once again guards the trocar and is locked against displacement relative to the trocar so that should the cannula and trocar be inadvertently pushed in through the abdominal wall to reach the underlying organs, little or no damage will be sustained by the organs.
  • the trocar can now be removed to provide access to the abdominal cavity via the cannula for various surgical devices and instruments.
  • a guard on the cannula rather than on the trocar has a number of advantages. Firstly, on the cannula there is more space in which to accommodate the spring mechanism. Secondly, the trocar without a guard and spring mechanism can more readily be disinfected and thirdly because the guard on the cannula can be more cheaply installed than on the trocar, the cannula can be made to be a disposable item.
  • An indicator (not shown) is provided to give indication that the guard is in the retracted or extended position or both.
  • the distal end of the guard is provided with a roughened exterior surface to provide a grip between the guard and the skin of the patient.
  • the spring may be mounted on the outside of the tail section and coupled to the pin.
  • the pin may be provided on the tail section 6 and the slot in the guard.
  • the pin may be provided on the guard to extend radially inwardly and the slot provided in the stub shaft or vice versa.

Landscapes

  • Health & Medical Sciences (AREA)
  • Surgery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biomedical Technology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Engineering & Computer Science (AREA)
  • Pathology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Surgical Instruments (AREA)

Abstract

La présente invention concerne une canule (2) pourvue d'une garde rétractable lui permettant de s'utiliser avec un trocart (10) démuni de garde. Cette garde (8), qui comporte un collerette dont le diamètre externe est égal au diamètre externe de la canule, comporte également un manchon tubulaire (20) jouant de façon télescopique à l'intérieur de la canule (2). Une broche (32) équipant le manchon (20) pénètre dans une fente en L (34) ménagée dans la canule. Un ressort à boudin (3) pousse la broche vers une extrémité de la fente de façon à verrouiller la garde en une position dépliée selon laquelle la garde peut remplir son office par rapport à la tête du trocart (10). Pour dégager la garde (8), il suffit de faire tourner la canule contre le sens d'action du ressort jusqu'à la position selon laquelle il est possible de pousser la broche (32) vers l'extrémité opposée de la fente.
PCT/GB1996/000521 1996-03-07 1996-03-07 Canule pour un systeme de trocart WO1997032530A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/GB1996/000521 WO1997032530A1 (fr) 1996-03-07 1996-03-07 Canule pour un systeme de trocart

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/GB1996/000521 WO1997032530A1 (fr) 1996-03-07 1996-03-07 Canule pour un systeme de trocart

Publications (1)

Publication Number Publication Date
WO1997032530A1 true WO1997032530A1 (fr) 1997-09-12

Family

ID=10786880

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1996/000521 WO1997032530A1 (fr) 1996-03-07 1996-03-07 Canule pour un systeme de trocart

Country Status (1)

Country Link
WO (1) WO1997032530A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1778105A4 (fr) * 2004-08-03 2010-11-10 Trokamed Gmbh Trocart a surface de decoupe retractable

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0495633A1 (fr) * 1991-01-15 1992-07-22 Ethicon, Inc. Lame pour un trocart chirurgical
GB2295319A (en) * 1994-10-14 1996-05-29 Microsurgical Equipment Ltd Guarded cannula for a trocar system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0495633A1 (fr) * 1991-01-15 1992-07-22 Ethicon, Inc. Lame pour un trocart chirurgical
GB2295319A (en) * 1994-10-14 1996-05-29 Microsurgical Equipment Ltd Guarded cannula for a trocar system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1778105A4 (fr) * 2004-08-03 2010-11-10 Trokamed Gmbh Trocart a surface de decoupe retractable

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