Endoscopic medical instrument and related methods of use

A medical instrument has a tubular member having a distal end and a proximal end, a handle attached to the proximal end of the tubular member, a distal assembly including a pivot and an end effector assembly supported on the pivot. The end effector assembly has a pair of end effectors. The medical instrument also includes an elongate member corresponding to each of the pair of end effectors. Each elongate member extends through the tubular member and has a proximal end attached to the handle and a distal end attached to the end effector assembly.

FIELD OF THE INVENTION

The present invention relates to a medical instrument. More particularly, this invention relates to a medical instrument for performing an operation within a body cavity in conjunction with an endoscope, and, even more particularly, to an actuation mechanism for operating an end effector assembly of such an instrument.

BACKGROUND OF THE INVENTION

Various medical instruments may be used in connection with an endoscope for performing a number of operations at a site deep within a patient's body cavity. One such instrument, a biopsy forceps device, samples tissue from a body cavity with minimal intervention and discomfort to patients. Typically, a biopsy forceps device, like other endoscopic instruments, has a long flexible tubular member for insertion into a lumen of an endoscope. The tubular member is sufficiently long and flexible to follow a long, winding path of the body cavity. An end effector assembly, such as a biopsy forceps assembly, is attached at a distal end of the tubular member, and a handle is attached at a proximal end of the tubular member. An elongate mechanism, such as a pull wire, extends through the tubular member to connect the end effector assembly and the handle. A biopsy forceps assembly, for example, may include mating jaws actuated by the handle to sample a body tissue.

There are numerous types of endoscopic medical intruments in use today. These instruments have various actuator/end effector assemblies and connections configured to provide certain benefits. For example, one type of endoscopic medical instrument includes a single, elongate flexible pull wire extending through the instrument and connected at its distal end to a relatively rigid actuator having an axis along the instrument. That actuator includes a pair of pins at one end, each pin supporting an end of one link. The other end of each link connects to a jaw. A support pin supports the jaw assembly. This assembly can generate a relatively large closing force at the jaw assembly. The jaws of the jaw assembly pivot together about the support pin because they are connected to a single actuator. This limits the range of rotation of the jaws.

Another type of endoscopic medical instrument includes a pair of elongate, flexible pull wires extending through the instrument. Each wire connects at its distal end directly to a lever arm of a jaw. In this configuration, each jaw is supported on and pivots about a single pivot pin. With this assembly, as the wires are pulled proximally to close the jaws, the torque about the pivot pin decreases, thereby decreasing the closing force.

A further endoscopic medical instrument includes a jaw assembly with a pair of jaws connected to a pair of arms extending from a jaw housing. Each jaw has a shank that has a surface facing a surface on corresponding arms. A cam slot on each jaw shank is slidably engaged by a cam pin on the arms. A puller member axially movable within the housing supports a pair of pivots, each of which pivotally engages a jaw shank. The puller member is attached to a drive wire coaxially positioned in a tubular shaft such that axial movement of the drive wire actuates the puller member. In response to axial movement of the puller, the cam pins riding in the cam guide slots change the position relative to the fixed jaw pivot axis of the jaw, thus actuating the jaws.

Another endoscopic medical instrument includes a single flexible pull wire that connects at its distal end to a relatively short rigid tube. The tube extends over and moves axially relative to the jaw assembly to close the jaws.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, a medical instrument comprises a tubular member having a distal end and a proximal end, a handle attached to the proximal end of the tubular member, a pair of end effectors supported on a pivot, a link corresponding to each of the pair of end effectors, and an elongate member corresponding to each of the pair of end effectors. Each elongate member may extend through the tubular member and has a proximal end attached to the handle. A distal end of each link is connected to a corresponding end effector and a proximal end of each link is connected to a distal end of a corresponding elongate member.

According to another aspect of the invention, the medical instrument comprises a tubular member having a distal end and a proximal end, a handle attached to the proximal end of the tubular member, a distal assembly including a pivot and an end effector assembly supported on the pivot. The end effector assembly has a pair of end effectors. The distal assembly has a center axis and a pair of stops, each stop configured to prevent rotation of a corresponding end effector past the center axis. The medical instrument also includes an elongate member corresponding to each of the pair of end effectors. Each elongate member extends through the tubular member and has a proximal end attached to the handle and a distal end attached to the end effector assembly in a manner permitting positioning of one of the end effectors at a first angle relative to the center axis when the other of the end effectors is positioned at a second angle relative to the center axis that is different than the first angle.

In another aspect of the present invention, each of the elongate members may include a flexible wire. In a further aspect, each of the elongate members may include an actuator that has a proximal end connected to a distal end of the corresponding flexible wire and a distal end connected to a corresponding link. Each actuator may be more rigid than the corresponding flexible wire and may have a cross-section selected from one of semi-circular, circular, rectangular, and square.

In a further aspect, proximal displacement of the elongate member may cause a corresponding end effector to close while distal displacement of the elongate member may cause the corresponding end effector to open.

In still another aspect, each elongate member may be configured to move independently of the other elongate member.

In another aspect, the present invention may include a clevis attached to the distal end of the tubular member. The clevis may support a pivot pin that supports the end effectors. The clevis may have a center axis and each elongate member may extend substantially parallel to the center axis. In addition to the center axis, the clevis may also include a pair of stops where each stop is configured to prevent rotation of a corresponding end effector past the center axis. The clevis may have a main portion that has a through hole configured to receive the elongate members. The through hole may include two through holes, each being configured to receive one of the elongate members.

In a further aspect, each end effector may be a forceps jaw. One of the forceps jaws may have a planar distal portion and the other of the forceps jaws may have a cup-shaped distal portion. In a further aspect, regardless of the shape of the distal portions, at least one of the forceps jaws may include a cutting edge.

In yet another aspect, each end effector may include a first stop surface and a second stop surface. In a further aspect, the first stop surface of one of the end effectors may contact the second stop surface of the other of the end effectors to provide a maximum opening of the end effectors. In this arrangement, each elongate member may be configured to move independent of the other elongate member to allow the end effectors to rotate about the pivot when the end effectors are at the maximum opening.

In another aspect, at least the distal end of one elongate member may be displaceable a first amount proximally and at least the distal end of the other elongate member may be displaceable a second amount distally to allow the end effectors to rotate about the pivot. In addition, the first amount of displacement may be different than the second amount of displacement. This may allow the end effectors to rotate through different angles about the pivot.

According to other aspects, the present invention is directed to a method of performing a medical procedure. The method includes providing a medical instrument as set forth above, inserting the distal end of the tubular member and the pair of end effectors into a patient to a target site, manipulating the handle such that the elongate members are displaced to open the pair of end effectors, positioning the end effectors towards the target site, and manipulating the handle such that the elongate members are displaced to close the pair of end effectors on the target site to perform an operation. The term “providing” is used in a broad sense, and refers to, but is not limited to, making available for use, enabling useage, giving, supplying, obtaining, getting a hold of, acquiring, purchasing, selling, distributing, possessing, making ready for use, and/or placing in a position ready for use.

In another aspect, positioning the end effectors toward the target site may include contacting a tissue wall with one of the end effectors located proximally of the target site and displacing the tubular member to cause the end effectors to rotate towards the target site. Positioning the end effectors toward the target site may include contacting a tissue wall with one of the end effectors located distally of the target site and displacing the tubular member to cause the end effectors to rotate towards the target site.

In a further aspect, displacing the tubular member may cause the other end effector to contact one of the pair of stops of the distal assembly and prevent rotation of the other end effector past the center axis.

In another aspect, each end effector may include a first stop surface and a second stop surface, and displacing the tubular member may cause the first stop surface of one end effector to contact the second stop surface of the other end effector to provide a maximum opening of the end effectors.

In still another aspect, the end effectors may be forceps jaws and the operation may be to obtain a biopsy.

DESCRIPTION OF THE EMBODIMENTS

The various parts of the endoscopic medical instrument described herein may be made from any suitable biocompatible material known in the art.

The present invention relates to a medical instrument for, for example, use in conjunction with an endoscope for performing an operation within a body cavity of a patient. According to embodiments of the invention, the medical instrument generally includes an elongate, flexible tubular member having a distal end and a proximal end. A handle is attached to the proximal end of the tubular member. An end effector assembly, such as, for example, a biopsy forceps assembly, is attached to the distal end of the tubular member. A pair of elongate members, such as pull wires, connect at their proximal end to the handle, extend through the tubular member, and connect to end effectors at the distal end. In certain embodiments, the end effectors may be jaws of a jaw assembly.

According to embodiments of the invention, the medical instrument includes an actuator means for opening and closing the end effectors. The embodiments of the actuator mechanism provide a relatively large closing force, allow the end effector assembly to pivot more freely, and permit increased flexibility and ease of manipulation of the end effectors in situ without detraction of the closing force.

One exemplary actuator means includes a pair of actuators, each of which is connected at its distal end to an end effector via a link. Each proximal end of an actuator connects to a corresponding one of the pair of pull wires. This assembly permits each of the end effectors to pivot freely about a single pivot point while retaining a relatively large clamping force.

A further embodiment of actuation means includes passing the pair of pull wires through a distal clevis in separate holes extending through the clevis. Each of the pull wires connects at its proximal end to a handle and at its distal end to one of the end effectors. The geometry of the through holes in the clevis can be controlled so that the pull wires are constrained to move at an angle with respect to a centerline of the endoscopic medical instrument to provide for more torque and to increase the closing force.

Another embodiment of the actuation means includes a collar that is attached to the pull wires. The geometry of the collar is configured to interact with the clevis to generate an inwardly bending of the distal ends of the pull wires. This inwardly bending will also increase the amount of closing force generated.

Embodiments of the present invention will be shown and described in connection with biopsy forceps devices and forceps assemblies having a pair of jaws as end effectors. However, the actuation mechanisms are suitable for other types of endoscopic, laparoscopic, or other instruments and other types of end effector assemblies and end effectors, such as graspers, cutters, clampers, or other devices known in the art. The biopsy forceps devices shown and described are exemplary only.

In an embodiment of the present invention shown inFIG. 1, a biopsy forceps device20has a flexible tubular member22having a distal end24and a proximal end26. During an operation on a patient to obtain a biopsy, distal end24travels through a lumen of an endoscope and the patient's body cavity. Proximal end26of tubular member22remains outside the body cavity.

Tubular member22should be made of a material that has sufficient stiffness, elasticity, and maneuverability to sustain, for example, bending and shear forces incurred during an endoscopic operation. As best seen inFIGS. 2 and 3, the tubular member22may be made of a helical coil28covered with an outer sheath30(shown inFIG. 1). Tubular member22may be any suitable tubular member, such as, for example, a hollow, coil-less structure, and may be made of any suitable biocompatible materials known in the art.

As shown inFIG. 1, a handle32is attached to the proximal end of tubular member22. Handle32is used to control or actuate a biopsy forceps assembly34within a body cavity. The handle32may be a conventional spool and shaft actuator having a spool36surrounding a shaft38that includes a thumb ring40. A pair of flexible pull wires42of substantially equal length are attached to spool36in a manner well known in the art. The pull wires42are made out of steel or any other suitable material. A typical spool and shaft actuator is described in detail in U.S. Pat. No. 5,133,727, which is incorporated herein by reference. Other types of handles known in the art can also be used in combination with the tubular member and actuation mechanism of this invention. The handle shown and described is exemplary only.

As shown inFIGS. 1-3, an end effector assembly, for example, biopsy forceps assembly34includes a clevis44and a pair of end effectors, for example, forceps jaws46, each of which is a duplicate of the other, pivotally connected to the clevis44via a clevis pin48. Each pull wire42partially extends into the clevis44and attaches to a proximal end of one of a pair of actuators50. Each actuator50is connected, in turn, to a proximal end of a link52near the distal end of the actuator via a pin54extending from the actuator50. A distal end of each link52is connected to a tang56of a forceps jaw46extending proximally therefrom. The tang56includes a pin58to support the distal end of the link52. Each of the pins54and58could be replaced with other pin arrangements, such as, for example, pins extending from the links or pins extending through the actuators, links, or tangs, or any other suitable connection known in the art, without departing from the heart of the invention.

As shown inFIGS. 4-6, each actuator50includes a main body portion60having a semi-circular cross-section and a recessed portion62formed in the flat inner surface of the semi-circular cross-section for attachment to one of the pull wires42. The pin54extends from the outer surface of the actuator50opposite the flat surface of the semi-circular profile. In this configuration, both actuators50are free to move proximally and distally with respect to each other in the clevis44as the flat surface of one actuator50slides past the flat surface of the other actuator50. Although an actuator50having a semi-circular cross-section has been shown in detail, the main body portion60may take many different shapes, such as, for example, tubular, rectangular, square, each with or without keying features. Examples of these profiles are shown inFIGS. 11A-11Fand described below. Main body portions60of other cross-sections may be used.

FIGS. 7-9show an embodiment of the clevis44. Clevis44includes a cylindrical body portion63and a pair of clevis arms64,66extending from the body portion63and configured to hold the clevis pin48in bores71,73. Each of the clevis arms64,66includes a beveled surface leading to a stop68,70, respectively. These stops interact with stops on the jaws (as will be discussed below) to prevent over-rotation of the forceps jaws46beyond a center axis65of the clevis44.

Body portion63includes a through hole67sized to receive the proximal ends of both actuators50as shown inFIG. 10. In addition, as shown inFIG. 8, the proximal end of the clevis44includes a recessed portion69that is configured to affix the clevis to the tubular member22using any conventional means, such as, for example, crimping, swagging, gluing, laser welding, or otherwise adhering. Tubular member22may include a reduced diameter distal portion22areceived by recessed portion69.

FIGS. 11A-11Fshow additional embodiments of devises having alternative through hole arrangements. These embodiments accommodate corresponding actuators of the same cross-sections. Actuators of differing cross-sections may be used.FIGS. 11A-11Fshow similar components to those shown inFIG. 10and retain the same reference numerals with a letter matching the Figure number. In these Figures, the devises63include through holes67configured to receive actuators50having circular, rectangular, or square cross-sections. Other cross-sections may be used. The actuators also may include keying features.FIGS. 11A-11Cshow a single through hole, whileFIGS. 11D-11Fshow two through holes. By varying the number of through holes and the cross-sections, different bearing surfaces can be provided to increase or decrease resistance to side loadings.

Referring back toFIGS. 1-3, the forceps jaws46are pivotally connected to clevis44such that they can be opened and closed to obtain a sample of tissue from within a body cavity. The forceps jaws46may be pivotally connected to the clevis44by a pin48that extends through both clevis arms64,66or by any other suitable method known in the art, such as, for example, where the pin48extends from one of the clevis arms64,66through the forceps jaws46.

FIGS. 12 and 13show an exemplary embodiment of a forceps jaw46before being attached to the clevis44. Because the lower and upper jaws of this embodiment are substantially identical, only one jaw46will be described. Forceps jaw46, at its distal end, has a generally hemispherical shape with a cutting edge75located on a periphery. Alternatively, the cutting edge ring may be replaced with a plurality of teeth, if desired. A bore72is located within the tang portion56of jaw46. The bore72is configured to receive the clevis pin48and to allow the forceps jaw46to pivot about the clevis pin48. Jaw46also includes pin58that connects to the distal end of a link52.

Three stop surfaces74,76,78are provided to assist in preventing over extension of the forceps jaw46during use. Specifically, when the forceps jaws46are assembled with other parts of the biopsy forceps device, the stop surface74of one forceps jaw46will contact with stop surface76of the other forceps jaw46to define the maximum opening angle, such as, for example, 100 degrees, between the two forceps jaws46. This maximum open position is shown inFIGS. 2 and 3. Stop surfaces74,76could be formed to define any other desired maximum opening angle. Stop surface78cooperates with one of the two stops68,70of the clevis44to prevent the forceps jaws46from over-rotation past the center axis65of the clevis44.

Having described all of the major components of the medical instrument10, the use and operation of the instrument will now be described. To manipulate the opening and closing of the biopsy forceps assembly34, the spool36is moved proximally and distally along the shaft38. By moving the spool36distally, the pull wires42move distally causing the actuators50to move distally and to push on the proximal end of the links52. This motion forces the forceps jaws46to open, as shown inFIG. 2.

FIG. 2shows the forceps jaws46in a typical open configuration where the actuators50and the proximal ends of the links52have been displaced distally. By displacing the spool36proximally, the process is reversed and the forceps jaws46are closed and the cutting edges75can sever a biopsy sample from a tissue wall. The configuration of the actuation mechanism, including actuators50and links52, permits the biopsy forceps jaws46to freely pivot about the clevis pin48while maintaining a strong closing force.

InFIG. 3, the pull wire42, actuator50, and link52associated with the open forceps jaw46is displaced distally with respect to the other pull wire42, actuator50, and link52. To allow for such displacement, pull wire42may be configured to have some slack or to be pretensioned such that relative displacement of the link52and actuator50can be taken up by the pull wire42This allows one of the biopsy forceps jaws46to pivot about the clevis pin48independently of the other jaw46, and thereby permits an operator, during an operation, to more accurately position the open jaws46to collect a biopsy sample. Such pretensioning or slack may cause the distance the spool travels to be much greater than is necessary to actuate the actuator50and cause the jaws46to open and close. The pretensioning or slack may be desirable, for example, to allow for the coiling of the device for packaging purposes or to allow for greater precision in actuating the actuator50and cause the jaws46to open and close.

During an operation, the distal end24of the elongate tube22and end effectors assembly34are inserted into a lumen of an endoscope and introduced into the body cavity of a patient. After reaching a target site where a medical procedure is to be performed on a portion of the body, such as, for example, obtaining a biopsy from a tissue wall, the spool36is displaced distally to open the end effectors46. Next, the end effectors assembly34is moved into contact with the portion of the body. If the end effectors assembly34is not properly aligned, the distal portion24of the tubular member22may be manipulated so that the distal end of one end effector contacts the portion of the tissue wall proximal to the site from which a biopsy is desired. Alternatively, the distal end of the other end effector can contact the tissue wall opposing the site of interest. Then, the tubular member22may be further displaced distally, such as by pushing the entire device at the endoscope handle, thereby causing the end effector to bear on the tissue wall and rotate the end effector assembly34about the clevis pin48into position to act on the tissue wall. The slack or pretension in the pull wires42will allow this rotation. As shown inFIG. 3, the end effectors assembly34has rotated downward as if the lower end effector had contacted the tissue wall.

In the instance where the medical procedure to be performed is to obtain a biopsy, the cutting edge75of the lower biopsy jaw46contacts the tissue to be sampled. Further displacement of the tubular member22causes the end effectors assembly34to rotate (as shown inFIG. 3), thereby bringing the cutting edge75of the upper biopsy jaw46into contact with the tissue. The spool36then is displaced proximally to close the end effector assembly to complete the procedure. By displacing the spool36proximally, both actuators50will eventually move into alignment such that the end effectors will close substantially parallel to the center axis65of the clevis44. This will occur because the slack will be taken up or the original pretension of the pull wire46will be restored. In some instances, the distal portion24of the tubular member22may bend upwards or downwards to allow the end effectors to close substantially parallel to the center axis65. Similar results will occur if it is necessary to approach a tissue wall tangentially. The jaws46of the biopsy forceps assembly34will be able to rotate into the proper position to collect the sample once contact is made with the tissue wall. Although the above procedure has been described in relation to a fully open end effector assembly, it should be apparent that the end effector assembly can be pivoted with the end effector assembly at any degree of opening between zero degrees and the maximum opening so long as the pull wires have sufficient slack or pretension.

As described above,FIG. 3shows one forceps jaws46in an open position while the other forceps jaw46is in a substantially closed position. The stop68on clevis arm64prevents the closed forceps jaw46from rotating past the center axis65. Since the jaws are also limited in their relative rotation by stops74,78, preventing rotation of one jaw past the center axis limits the rotation of the open jaw46relative to the center axis to the maximum opening angle. This keeps the corresponding link52of the closed jaw46from rotating into alignment with the center axis65. If such alignment were to occur (i.e. pull wire42, actuator50, link52, pin58, clevis pin48and center axis65are substantially in alignment), it would be difficult to close the forceps jaw46open or closed because there would be little or no torque available to cause the forceps jaw46to rotate about the clevis pin48. The geometry of the forceps jaws46and the stops68,70on clevis arms64,66are configured to provide an angle greater than zero, for example, 15 degrees, between the center axis65of the clevis44and a longitudinal axis of the link52to avoid this problem.

In addition, this configuration of the links52and forceps jaws46ensures there will always be some closing force applied at the distal portion of the forceps jaws46during proximal displacement of the actuators50. This is caused because there will always be a component of force from the proximal displacement of the spool acting perpendicular to a moment arm between the center of pin58and clevis pin48, thereby providing a closing force on the distal end of the forceps jaws46.

FIGS. 14-17show an alternative embodiment of the forceps jaws46described above.FIGS. 14 and 15show a forceps jaw assembly80that is configured similar to forceps jaw46, with the exception that the forceps jaw80has a substantially planar distal portion as opposed to a substantially cup-shaped distal portion. Jaw80includes a tang portion82, pin84, and stop surfaces86,88,90that are structurally and functionally similar to those described for the forceps jaw46.

FIGS. 16 and 17show a forceps jaw assembly92for opposing jaw assembly80. Assembly92is substantially similar to the forceps jaw46. Jaw92includes a tang portion94, pin96, cutting edge98, and stop surfaces100,102,104that are structurally and functionally similar to those described for the forceps jaw46.

An endoscopic medical instrument having forceps jaws80,92will operate substantially similarly to the operation described with respect to the instrument having forceps jaws46. Because the forceps jaw80does not have a cutting edge, however, the biopsy sample is taken by pressing the cutting edge98of jaw92against the planar surface of forceps jaw80. In all other aspects, this instrument may be used in the same manner as described above.

FIG. 18shows an embodiment where the clevis144has two through holes167radially offset from a centerline of the endoscopic instrument. The pull wires142run through their respective through holes167and then cross once they exit the clevis144. The pull wires142are each connected to one of the forceps jaws146at coupling portion158of tang portion156. The forceps jaws146pivot about pin148on the clevis144. By arranging the device in this manner, the angle at which the pull wire142acts on tang portion156when the pull wires142are moved proximally relative to the clevis144allows an increase in the closing force of the forceps jaws146.

FIGS. 19 and 20show an embodiment where the pull wires242extend through the same hole267of the clevis244and are each connected to one of the forceps jaws246at coupling portion258of tang portion256. The pull wires242each have a collar200fixed to it between the clevis244and the forceps jaw246. When the pull wire242is moved proximally relative to the clevis244, the chamfered end of the collar200comes into contact with a corresponding chamfered portion of the clevis244. The contact causes the central axis of the collar200to become concentric with the central axis of the clevis244, and in doing so causes an increase in the closing force of the forceps jaws146.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and illustrated examples are exemplary only, the true scope and spirit of the invention being apparent from the following claims.