Laparoscopic bipolar electrosurgical instrument

• US 6,451,018 B1
• Filed: 06/09/2000
• Issued: 09/17/2002
• Est. Priority Date: 11/14/1997
• Status: Expired due to Term

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Sherwood Services AG
• Inventors: Lukianow, Stephen Wade, Lands, Michael John, Loeffler, Donald Robert, Cunnigham, James Steven, Lawes, Kate Ryland, Kennedy, Jenifer Serafin, Mitchell, Mathew Erle, Trimberger, Daniel Lee II
• Primary Examiner(s): COHEN, LEE S
• Application Number:
  US09/591,330
• Time in Patent Office: 830 Days
• Field of Search: 606/46, 606/48-52, 606/170, 606/207, 606/208
• US Class Current: 606/50
• CPC Class Codes: A61B 18/1445 at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod

Abstract

A laparoscopic bipolar electrosurgical instrument can apply a large closure force between its jaws without damaging the small yoke assembly. The instrument comprises: a first jaw having a first flange with a first slot, and a second jaw having a second flange with a second slot, wherein the first and second jaws are located at a distal end of the instrument and comprise an electrically conductive material for conducting bipolar electrosurgical current therebetween; a yoke attached to a pushrod and positioned to electrically insulate the first flange from the second flange, the yoke having a first side facing the first flange and a second side facing the second flange, the yoke further comprising a first shoulder and a second shoulder; a first pin located on the first side and movably engaged with the first slot; a second pin located on the second side and movably engaged with the second slot; the first slot and the second slot shaped such that an angle, subtended by the first and second jaws, decreases with distal motion of the pushrod, and first and second cul-de-sacs positioned respectively in the first and second slots to relieve shear stresses on the first and second pins approximately when the first and second shoulders respectively engage the first and second flanges to provide a closure force between the first and second jaws.

Claims

1. A laparoscopic bipolar endoscopic instrument, comprising:

first and second jaw members, one of the jaw members being movable relative to the other of the jaw members from a first open position wherein the jaw members are disposed in spaced relation relative to one another to a second clamping position wherein the jaw members cooperate to grasp tissue therebetween,

an electrically conductive push rod for connecting the first jaw member to a first electrical potential and an electrically conductive tube for connecting the second jaw member to a second electrical potential such that the jaw members are capable of conducting bipolar energy through the tissue held therebetween;

a yoke having at least one pin attached thereto which slidably engages the law members, the yoke being movable such that the pin imparts movement of the jaw members from the first and second positions;

a pair of shoulder portions attached to the yoke which are configured to abut the jaw members when the jaw members are moved into the second position to relieve shear stress on the pin during clamping and sealing of the tissue; and

a handle which cooperates with the push rod for imparting movement to the yoke.

2. The laparoscopic bipolar electrosurgical instrument of claim 1 wherein the electrically conductive tube surrounds at least a portion of the pushrod, and an electrically insulative layer is disposed between the tube and the pushrod capable of supporting an electrosurgical alternating potential across the tube and the pushrod.

3. The laparoscopic bipolar electrosurgical instrument of claim 2 further comprising:

an inner nose piece electrically connected to the pushrod, and

an outer nose piece electrically connected to the tube, wherein the inner nose piece and the outer nose piece capture the yoke to conduct bipolar electrosurgical current to the first and second jaw members.

4. The laparoscopic bipolar electrosurgical instrument of claim 3 further comprising an electrical spring contact between the pushrod and the inner nose piece to provide electrical continuity therebetween.

5. The laparoscopic bipolar electrosurgical instrument of claim 1 further comprising ridges in each of the first and second jaw members.

6. The laparoscopic bipolar electrosurgical instrument of claim 1 wherein each of the first and second jaw members has a seal surface with width and a length, and wherein at least one location along the length has a width such that the closure force in grams divided by the width in millimeters is in the range of 400 to 650.

7. The laparoscopic bipolar electrosurgical instrument of claim 6 wherein the width of at least one of the seal surfaces is tapered along its respective length.

8. The laparoscopic bipolar electrosurgical instrument of claim 7 wherein the closure force in grams divided by the width in millimeters is approximately constant along the length for each of the first and second jaw members.