Patent Application
20060271042
I. Field of the Invention
The present invention relates generally to electrosurgical instruments, and more particularly to a bipolar electrosurgical device for coagulation and cutting of target tissue and specifically designed for use in the performance of percutaneous laparoscopic surgery or other endoscopic procedures.
II. Background of the Invention
For a number of years, the medical device industry, in cooperation with healthcare providers, has been developing methods and devices to permit surgical procedures to be performed in a less invasive manner. Minimally invasive surgery generally involves the use of instruments that avoid the need to make major incisions in the body. Major incisions usually require a relatively long period of hospitalization and subsequent home recovery. Minimally invasive surgery has the salutary effects of shortening hospital stays and recovery times.
Minimally invasive surgical procedures are generally performed through a trocar cannula. The cutting and coagulating instruments most often used are either electrosurgical or laser-based. While, generally speaking, laser based instruments are capable of more precise cutting than electrosurgical instruments, they are somewhat difficult to control, particularly in the close conditions of laparoscopic procedures.
Electrosurgical instruments are either monopolar or bipolar in nature. In monopolar electro surgery, there is a greater potential for injury to body tissues because an electric current most pass through the tissues on a “path of least resistance” basis to a return electrode located on the patient's skin. In laparoscopic procedures, there is even a greater potential for complications when using monopolar instruments, due to the combined effects of the surgeon's limited field of vision, the proximity of other organs to the tissue being cut and the inherent tendency of monopolar RF energy to find a somewhat random path back to the return electrode.
Bipolar electrosurgical instruments provide an improved margin of patient safety in certain minimally invasive surgical and interventional procedures. In the case of bipolar devices, the RF energy is contained at the surgical site because both the active electrode and the return electrode are located in close proximity to one another on the surgical instrument itself.
Bipolar coagulating and cutting forceps are known in the art, examples of which may be found in U.S. Pat. Nos. 5,258,006, 5,445,638, and 5,562,546 to Rydell et al. The forceps jaws are used for grasping or gripping the tissue to be cut. A RF current may be made to pass through the tissue disposed between the clamped jaws to desiccate the tissue and then, in the case of the Rydell et al. '638 patent, a mechanical cutting blade may be actuated and made to pass through the clamped tissue to sever it.
U.S. Pat. No. 5,735,849 to Baden et al. describes an endoscopic, electrosurgical forceps having an elongated tubular barrel that has coagulating electrodes on the opposed jaw surfaces and a cutting blade similar to that which is disclosed in the Rydell '638 patent but with an improved handle mechanism that allows the surgeon to select between a bi-directional mode or a uni-directional mode of jaw movement. In each instance, however, the electrode surfaces on the jaws approach one another in a relative parallel relationship during jaw closure and likewise, separate from one another in a relative parallel relation as the jaws are made to open. Maintaining this parallel relationship results in improved and more uniform coagulation but suffers a drawback that the amount of separation of the opposed jaw surfaces is somewhat limited, making it more difficult to place the open jaws about target tissue prior to jaw closure, desiccation and cutting.
Consequently, a need exists for an electrosurgical forceps instrument that allows significantly wider jaw separation when the jaws are fully opened relative to one another but which will assume a more parallel movement as they are made to close upon target tissue captured therebetween.
Given the constraints imposed on the surgeon while performing minimally invasive surgery through a trocar or the like, it would also be advantageous if the jaw assembly can be redirected via a control lever on the instrument's handle without having to reposition the trocar. The ability to redirect the angle at which the jaws extend from the instrument's tubular barrel facilitates the ability of the surgeon to gain purchase to target tissue during the course of a laparoscopic procedure. This is especially true when the instrument also has the capability of being able to rotate the barrel and jaw assembly without moving the handle, a feature disclosed in the Rydell et al. '006 patent.
The above-described drawbacks of prior art electrosurgical forceps are obviated by the cutting and coagulating electrosurgical forceps of the present invention. It comprises an elongated tubular barrel having a proximal end, a distal end and a lumen extending therebetween. A handle is provided at the proximal end of the barrel and includes an actuating member on the handle. A pair of forceps jaws is mounted at the distal end of the barrel where each of the forceps jaws has cam slots formed through a proximal head portion to which the tissue engaging surfaces of the jaws are joined. A coupling member extends between the actuating member on the handle and the pair of forceps jaws where the coupling member includes members that cooperate with the cam slots such that by squeezing the actuating mechanism effects pivotal rotation of the pair of forceps jaws over a first range of motion of the actuating member and translation without rotation of the pair of forceps jaws over a second range of motion of the actuating member.
For example, and without limitation, the handle may have a pistol grip configuration with the “actuating member” being the trigger on the pistol grip. Initially, the individual jaw members may be at a predetermined angle with respect to one another and as the trigger is squeezed, the angle decreases to a point where the opposed jaw surfaces carrying the electrodes are parallel to one another and then continued squeezing of the trigger over a second range of motion brings the two jaws together in a parallel manner.
As a further feature of the invention, a thumb lever is provided on the handle that is operatively coupled to the jaw assembly which is pivotally secured at the distal end of the elongated barrel whereby actuation of the thumb lever redirects the angle at which the jaw assembly projects from the distal end of the elongated barrel.
The instrument further includes a reciprocally movable cutting blade disposed at the distal end of the tubular barrel and it can be made to project out the distal end of the barrel between the closed forceps jaws through actuation of a pushrod that is attached to the blade and that extends through the lumen of the barrel to a control lever on the handle.
These and other objects, advantages and features of the invention will become apparent to persons skilled in the art from the following detailed description of a preferred embodiment depicting the best mode contemplated for carrying out the invention. In the drawings, like numerals in the several views refer to corresponding parts.
Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “upwardly”, “downwardly”, “rightwardly”, “leftwardly”, “distally” and “proximally” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the device and associated parts thereof. Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import.
Referring to
It is seen to include an elongated tubular barrel 12 having a proximal end 14, a distal end 16 and a lumen 18 (
Located at the distal end 16 of the tubular barrel 12 is a forceps jaw assembly 24 including a pair of cooperating jaw members 26 and 28 (
Projecting out from opposed side surfaces of the handle 30 are thumb levers 34 which when depressed so as to pivot counterclockwise when viewed in
Also shown in
Another feature illustrated in
An electrical adapter 43 connects to a cord 45 that extends through the handle and down the tubular barrel's lumen 18 to connect to electrode structures on facing surfaces of jaws 26 and 28 in a manner to be further described herein below.
Having generally described the basic constructional features of the bipolar electrosurgical forceps, consideration will next be given to the mechanisms contained in the handle for controlling movements of the jaw assembly 24 from side to side, the movement of the jaws 26 and 28 from their open to their closed position, the movement of the instrument's cutting blade and the rotation of the blade assembly 24 through about 180° with respect to the longitudinal axis of the barrel 18.
With continued reference to
The jaw drive rod 54 passes through a small aperture formed through a pawl 62 that is canted at a slight angle to the axis of the drive rod by a spring 63 and the tolerances are such that when the pawl is canted at an angle to the axis of the drive rod 54, the drive rod can be moved in the proximal direction as the trigger 32 is squeezed, but is prevented from returning in the distal direction by the frictional engagement between the rod 54 and the pawl 62. However, when the pawl 62 is oriented perpendicularly to the drive rod 54 rather than at an angle, there is no longer interference between the pawl and the drive rod and the spring 46 is able to move the drive rod 54 in the distal direction. Actuation of the ratchet release 42 serves to orient the pawl 62 perpendicularly to the drive rod.
Also extending through the lumen 18 of the tubular barrel 12 is a blade push tube 65 that is affixed to the thumb lever 34 and that surrounds the jaw drive rod 54.
The thumb lever 34 is urged in the clockwise direction when viewed as in
With continued reference to
Turning next to the exploded view of
Formed on the distal end of the articulation drive tube 70 is a T-shaped tab 74 that is designed to fit within a T-shaped pocket 76 formed on a jaw support member 78. While not visible in
Sandwiched between the jaw supports 78 and 82 are the forceps jaw members 26 and 28. Each jaw member includes a head portion 90 and a jaw portion 92. The head portion 90 of the jaw member 28 includes a first slot 94 that is diagonally oriented relative to a longitudinal axis of the jaw member 28. A second cam slot 96 is also formed on the head portion 90 of the jaw member 28 and it is somewhat L-shaped with a stem segment 98 of the L generally aligned parallel to the cam slot 94 and a base segment 100 of the L that is at a predetermined angle to the stem segment 98. Likewise, the head portion 90 of the jaw member 26 has a cam slot 102 oriented diagonally to a longitudinal axis of jaw member 26 as well as a complimentary L-shaped cam slot 104 with a stem segment 106 that runs parallel to the cam slot 102 and a base segment 108 that is at an angle to the stem segment.
The hub 90 of the jaw member 28 further includes a slot 110 that is oriented generally perpendicular to the longitudinal axis of the jaw member. While not visible in
When the jaw supports 78 and 82 are made to sandwich the head portions jaw members 26 and 28, the drive pins 58 and 60 projecting laterally from the drive strap 56, fit into the above-described cam slots on the jaw members. More particularly, drive pin 58 is made to reside in the cam slots 96 and 104 while drive pin 60 extends into the slots 94 and 102. Short, stub-like pins, as at 112, project outward from the inner face of the jaw support members so as to reside in the slots 110 in the respective jaw members.
With the jaw supports and jaws so arranged and with the protuberances, like 86 on the jaw support members 82 and 78, located within the apertures 80 and 88, the jaw assemblies can be made to swing through a predetermined arc, as illustrated in
Turning now to
It is to be seen, then, that by providing the cam slots in the jaw member heads, the resulting electrosurgical forceps instrument allows significantly wider jaw tip separation when the jaws are fully open relative to one another, but that will assume a parallel movement as they are made to close upon target tissue captured between the tissue engaging portions of the jaws. This results in greater ease in gaining purchase of the target tissue while still providing improved electrocoagulation achieved when parallel jaw movement is involved.
This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.
