WO2008056618A2

WO2008056618A2 - Stapling instrument

Info

Publication number: WO2008056618A2
Application number: PCT/JP2007/071439
Authority: WO
Inventors: Shinichi Miyata; Atsunori Kozuki; Hiroshi Horikawa
Original assignee: Johnson & Johnson Kabushiki Kaisha
Priority date: 2006-11-06
Filing date: 2007-10-29
Publication date: 2008-05-15
Also published as: JP5021028B2; WO2008056618A3; JP2010508873A

Abstract

[Problem] To provide a stapling instrument capable of preventing body tissue from slipping between a cartridge and an anvil and hence firmly hold therebetween the body tissue during stapling. [Means for Solving the Problem] With the stapling instrument according to the present invention, squeezing a closing lever 40 causes a closing pipe 4 to slide forwardly, pressing a second coupling member 16 forwardly. The pressed second coupling member 16 moves along curved, elongated grooves 12b while pivoting, causing first coupling members 14 to pivot forwardly. An anvil 6 linked to the first and second coupling members 14 and 16 closes with respect to a cartridge 5 in parallel thereto.

Description

DESCRIPTION STAPLING INSTRUMENT [Technical Field] [0001] The present invention relates to a surgical instrument for use in surgical procedures and, more particularly, to a stapling instrument for stitching body tissue by stapling. [Background Art] [0002] Surgical stapling apparatuses are widely used in surgical operations which typically comprise: an elongated, tubular insert section having pivotally mounted thereon at the distal end portion thereof an anvil rotatable with respect to a staple cartridge between an open position and a closed position; and a gun-grip-type handle portion coupled to the proximal end portion of the insert section.

With the use of such a stapling instrument, the insert section is first introduced into a patient's body, followed by driving two or more rows of staples from the staple cartridge into the body tissue, and then by ablating the body tissue longitudinally between the rows of stitching staples by means of a knife, thus simultaneously effecting suturing the body tissue and ablation of the affected part. [0003]

Fig. 1 shows in perspective a conventional stapling instrument. The illustrated stapling instrument, generally designated by 1, is provided with a cartridge 5 for housing a plurality of lines of staples, and an anvil 6 having a plurality of grooves for curling the staple legs into hook form. The stapling instrument 1 is designed so that, while in use, the staples are driven out from the cartridge 5 into body tissue clamped between the anvil 6 and the cartridge 5, while at the same time the body tissue is ablated by a knife between the plurality of rows of stitched staples . [0004]

More specifically, squeezing a closing lever 40 toward a handle grip causes the anvil 6 to pivot toward the staple cartridge 5, clamping body tissue between the anvil 6 and the cartridge 5. Subsequent squeezing of a staple firing lever 27 similarly toward the handle grip causes a cam bar housed in the insert section 2 to move toward the distal end of the cartridge 5 along a cam bar slot formed in the back of the cartridge 5, bringing the distal end of the cam bar into abutment against a staple holding member to push it toward the anvil 6, thus firing staples and causing sliding movement of a cutter in slots made in the surfaces of the cartridge 5 and the anvil 6. This operation achieves placement of rows of staples in the body tissue gripped by the anvil 6 and the cartridge 5, while at the same time cutting the tissue along a line between the longitudinal staple rows. Repetitive stapling enables ablation of an affected or desired part of the body tissue.

Releasing the staple firing lever 27, the cam bar and the knife slide in the slots back to their initial position under the action of a coiled spring disposed near the staple firing lever 27. ^; Then, pressing a release button 42 on the back of the handle portion, the anvil 6 becomes full-open with respect to the cartridge 5. [0005]

In patent documents 1 and 2 there is disclosed such a stapling apparatus provided with an insert section, anvil actuating means (closing lever 40) and staple firing means (staple firing lever 27) as described above. [0006]

[Patent Document 1] Pat. Appln. Kokai Pub. No. 2003-603

[Patent Document 2] Pat. Appln. Kokai Pub. No. 238947/97 [0007]

Since the conventional stapling apparatus has such a construction as mentioned above, the anvil 6, when closing with respect to the cartridge 5, rotates with its proximal end as a fulcrum, bringing its distal-most end portion into abutment against the body tissue. This structure gives rise to a problem that as the anvil 6 turns toward its closed position, the body tissue gripped between the anvil 6 and the cartridge 5 is apt to slip toward the distal end portion of the anvil 6.

[Disclosure of the Invention] [Problem to be Solved by the Invention] [0008]

The present invention is intended to solve such a problem as mentioned above, and has for its object to provide a stapling instrument which prevents body tissue from slipping between the cartridge and the anvil during stapling to firmly hold therebetween the body tissue. [Means for Solving the Problem] [0009] The stapling instrument according to the present invention includes an insert section and a handle portion connected to the insert section and having an anvil actuating means and a staple firing means.

The insert section includes: an anvil which is -rotatable with respect to a staple cartridge between an open position and a closed position; a cartridge holder which holds said cartridge; a first coupling member which is linked at one end to said cartridge holder by engagement therewith of a first stub shaft disposed at said one end of said first coupling member through a hole and is linked at the other end to said anvil through a first coupling portion; a second coupling member which is linked at one end to said cartridge holder by engagement of a second stub shaft disposed at said one end of said second coupling member with a groove made in said cartridge holder and which is linked at the other end to said anvil through a second coupling portion; and a closing pipe linked to said anvil actuating means and disposed behind said cartridge holder and slidable back and forth. The stapling instrument of the present invention is characterized in that upon operating said anvil actuating means, said closing pipe slides to press said second coupling member forward, then said second coupling member thus pressed moves along said groove while pivoting, then said first coupling member pivots forwardly about said first stub shaft, and said anvil linked to said first and second coupling members become closed with respect to said cartridge in parallel thereto.

[0010]

The stapling instrument of the present invention is characterized in that: the distance between said first coupling portion and said first stub shaft and the distance between said second coupling portion and said second stub shaft are equal to each other; and when said anvil is full-closed with respect to said cartridge, the distance between said first coupling portion and said second coupling portion and the distance between said first stub shaft and said second stub shaft are equal to each other, and said first coupling portion, said second coupling portion, said first stub shaft and said second stub shaft form vertexes of a parallelogram.

[0011]

The stapling instrument of the present 'invention is characterized in that: a notch is made in the foremost portion of said groove of said cartridge holder; and when said anvil is full-closed with respect to said cartridge, said second stub shaft engages in said notch.

[0012]

The stapling instrument of the present invention is characterized in that: the angle of pivoting of said second stub shaft from the position where said second stub shaft engages in said notch to the position where said anvil becomes full-closed with respect to said cartridge is equal to or smaller than

20°.

[0013]

The stapling instrument of the present invention is characterized in that: said closing pipe has a hole in the top of its forward portion; and a projection provided on said second coupling member engages in said hole. [0014]

The stapling instrument of the present invention is characterized in that: said closing pipe has a pin disposed at the forward part of said hole in a direction perpendicular to the axis of said closing pipe; and said pin engages in a groove cut in said second coupling member forward of said projection. [0015] ' ^/

The stapling instrument of the present invention is characterized in that: a cam bar extended from said handle portion toward said insert section is linked to said staple firing lever; and upon actuation of said staple firing means, said cam bar pushes up a staple hold member disposed near a staple storage magazine in said cartridge to thereby fire a staple. [0016]

The stapling instrument of the present invention is characterized in that: a knife extended from said handle portion toward said insert section is linked to said staple firing means, together with said cam bar; and upon actuation of said staple firing means, said knife slides forward. [0017]

The stapling instrument of the present invention is characterized in that: said anvil has on both sides thereof downward projecting guides; and when said anvil is in a closed position with respect to said cartridge, said guides lie on both sides of said cartridge holder. [Effect of the Invention] [0018] According to the stapling instrument of the present invention, the use of the four-joint link mechanism enables the anvil to go down to the closed position parallel to the cartridge to firmly hold the body tissue between the cartridge and the anvil, achieving stable stapling.

The configuration of this embodiment minimizes the mechanism for actuating the anvil, and hence it minimizes the diameter of the closing pipe accordingly, making it possible to offer a stapling instrument that permits the use therewith of a thin trocar.

[0019]

According to the stapling instrument of the present invention, the use of the above-mentioned so-called four-joint parallel link mechanism provides a uniform distribution of force for pressing the cartridge by the anvil and hence produces a sufficient amount of grasping force to prevent slipping of body tissue between the cartridge and the anvil, firmly holding the body tissue during stapling. [0020]

According to the stapling instrument of the present invention, it is possible to prevent the anvil from opening due to a load or the like by stapling.

[0021] According to the stapling instrument of the present invention, since the degree of scraping the body tissue lowers between the anvil and the cartridge during the parallel closing operation, damage to the body tissue can be reduced.

[0022] According to the present invention, the movement of the parallel closing mechanism in its entirety can be controlled by controlling the movement of the second coupling member.

[0023]

According to the stapling instrument of the present invention, the movement of the parallel closing mechanism in its entirety can be controlled with higher accuracy.

[0024]

According to the stapling instrument of the present invention, it is possible to perform stapling while holding body tissue between the anvil and the cartridge. [0025]

According to the stapling instrument of the present invention, it is possible to ablate body tissue simultaneously with stapling.

[0026] According to the stapling instrument of the present invention, it is possible to define alignment between the anvil and the cartridge holder

(cartridge).

[Best Mode for Carrying out the Invention]

[0027] To facilitate a better understanding of the present invention, a description will hereinafter be give, with respect to the accompanying drawings, of the best mode for carrying out the invention.

EMBODIMENT 1

Now, Embodiment 1 of the present invention will be described. Fig. 2 is a perspective view illustrating the whole structure of a stapling instrument according to Embodiment 1 of the invention. Fig. 3 is a sectional view of the Fig. 2 stapling instrument 1, with the anvil 6 full-open with respect to the cartridge 5. Incidentally, the Fig. 3 state of the stapling instrument 1 is defined herein as its initial state. The stapling instrument 1 comprises an elongated, tubular insert section 2 for insertion into a patient's body, and a gun-grip-type handle portion 3 coupled to the proximal end portion of the insert section 2. The insert section 2 has slidably mounted thereon a closing pipe 4 near the distal end thereof, and has its distal end portion comprised of an anvil 6 rotatable with respect to the cartridge 5 between an open position and a closed position, first and second coupling members 14 and 16 for controlling the attitude of the anvil, and a cartridge holder 12.

[0028]

Referring to Figs. 3 and 4, the structure of the distal end portion of the insert section 2 will herein below be described. Fig. 4 is an exploded perspective view showing the distal end portion of the insert section 2 in the stapling instrument 1 of Fig. 2.

The cartridge holder 12 is substantially U-shaped in cross section, and has detachably received therein the cartridge 5. Furthermore, the cartridge holder 12 has a pair of notches 12e formed in both sides of its forward portion for locking the cartridge 5. On the other hand, the cartridge 5 has a pair of engaging protrusions 5 a provided on both sides of its forward portion. The engaging protrusions 5a of the cartridge 5 are engageable in and disengageable from the notches 12e of the cartridge holder 12. [0029]

The anvil 6 has a pair of right and left guides 6a disposed at somewhat rearward positions in its lengthwise direction. The guides 6a are located such that they grip therebetween the cartridge holder 12 when the anvil 6 is in the closed position, serving to define alignment between the anvil 6 and the cartridge holder 12 (cartridge 5). Incidentally, the guides 6a are not limited specifically to the illustrated configuration and disposition, and they may also dispensed with.

The proximal end portion of the anvil 6 in the direction toward the handle portion 3 is pivotally secured to end portions of first and second coupling members 14 and 16 by means of stub shafts (coupling portions) 13a and 13b, respectively.

On both outer sides of the other end portions of the first and second coupling members 14 and 16 there are protrusively provided stub shafts 14a and 16a. On the other hand, the cartridge holder 12 has holes 12a and curved, elongated grooves 12 bored through both side walls of its proximal or rearward portion.

The stud shafts 14a of the first coupling members 14 are received in the holes 12a, permitting the first coupling members 14 to pivot about the stub shafts 14a. The stud shafts 16a of the second coupling member 16 engage in the curved, elongated grooves 12b and move along the grooves 12b while rotating. Tliis allows the second coupling member 16 to pivot and move back and forth.

[0030]

When the anvil 6 is closed with respect to the cartridge 5, the first coupling members 14 are held in grooves 16e cut in the bottom of the second coupling member 16. The first coupling members 14 each have substantially centrally thereof a semicircular recess 14b for receiving the stub shaft 13b in the above situation.

The second coupling member 16 has a projection 16b formed on the top of its rearward portion, a groove 16c cut therein forward of the projection

16b, and a stopper 16d provided forward of the groove 16c. The closing pipe 4 has a hole 4a in the top of its distal or forward end and a pin 4b disposed forward of the hole 4a.

The projection 16b engages in the hole 4a, and the pin 4b moves between the groove 16c in the top of the second coupling member 16 and the stopper 16d, controlling the movement of the second coupling member 16.

This serves to control the movement of the distal or forward end portion of the insert section 2 (hereinafter referred to as a parallel closing mechanism) in its entirety. The operation of the parallel closing mechanism will be described later in detail.

[0031]

Turning next to Figs. 4 to 6, a description will be given of the actual stapling of body tissue. Fig. 5 is an enlarged sectional view illustrating stapling of body tissue by the stapling instrument 1 of Fig. 2. Fig. 6 is an exploded perspective view showing the insert section of the Fig. 2 stapling instrument and its vicinity.

The cartridge 5 has formed therein a staple storage magazine 8 in which a plurality of lines of substantially U-shaped staples 7 made of titanium or similar biocompatible material are releasably housed (see Fig. 5) with their both legs directed toward the anvil 6. The number of lines of staples housed in the staple storage magazine 8 of the cartridge 5 is four in Embodiment 1

(Fig. 4).

[0032]

As depicted in Fig. 5, in the staple storage magazine 8, there is disposed a staple hold member 10 under each staple 7. The staple hold member 10 has its underside sloped to push out the staple 7 toward the anvil 6. When held in touch with the staple I₇ the staple hold member 10 is supported slidably toward the anvil 6. Each staple hold member 10 holds two substantially aligned staples of adjoining lines of staples. [0033]

As depicted in Fig. 6, a knife 20 has at its distal end an edge forming a cutting blade. And the distal end portion of a cam bar 21 has a slope for pushing out the staple 7. The knife 20 and the cam bar 21 are connected at their proximal ends to a cam bar adaptor 23. The knife 20 and the cam bar 21 are slidable with respect to the cartridge 5. [0034]

As shown in Fig. 4, the cartridge 5 has a knife slot (not shown) cut in its surface facing the anvil 6 for guiding the knife 20 to slide between staple rows. In the underside of the anvil 6 facing the cartridge 5 there are cut grooves 11 for curling the staple legs into hook form and a guide groove 9 in which the edge of the knife 20 rides. In the underside of the cartridge 5 there is formed a cam bar slot (not shown) for guiding the cam bar 21 to move toward the position under the staple lines. [0035] As described above, as the cam bar 21 advances in the cam bar slot with the cartridge 5 and the anvil 6 gripping therebetween body tissue 44, it moves into sliding contact with the sloped underside of the staple hold member 10 and pushes it up toward the anvil 6, by which the staple 7 overlying the hold member is fired. The staples thus sequentially fired for each line are held between the grooves 11 of the anvil 6 and the cartridge 5 to staple the body tissue 44. As the same time, the knife 20 advances in the afore-mentioned knife slot and the guide groove 9, cutting the body tissue along a line centrally thereof (see Figs. 4 and 5). [0036] Referring next to Figs. 7 to 11, a description will be given of the operation of the parallel closing mechanism of the stapling instrument 1. Figs. 7 to 11 are sectional views showing a sequence of steps involved in the (parallel closing) operation of the parallel closing mechanism from a full-open position to a full-closed position. Fig. 7 is a sectional view of the operation of the parallel closing mechanism in the full-open position (initial state). For easy understanding, the second coupling member 16 is shown in side elevation, not in section. [0037]

In the initial state shown in Fig. 7, the pin 4b engages in the groove 16c and the projection 16b engages in the hole 4a. The first coupling members 14 pivot about the stub shafts 14a. Since the closing pipe 4 is pressed backward, the pin 4b also presses the projection 16b backward. As the result of this, the anvil 6 linked to the second coupling member 16 and the first coupling members 14 linked to the anvil 6 are also pressed backward. The first coupling members 14 linked to the anvil 6 rise upwardly, bringing the latter to the full-open position as shown. At this time the stub shafts 16a each lie at the rearmost end of the curve, elongated groove 12b. [0038]

Fig. 8 is a sectional view of the parallel closing mechanism, showing its operation subsequent to the sequence of steps described above with reference to Fig. 7. In the first place, the closing pipe 4 is pushed forward. At the same time, the pin 4b moves away from the projection 16b, and pushes forward along the inner wall of the groove 16c the second coupling member 16 located opposite the projection 16b. At the same time, the stub shaft 16a is displaced along the grooves 12b while rotating. As a result, the second coupling member 16 tilts forwardly while rising upwardly.

Since the distance Ll between the stub shafts 13a and 13b is fixed, the stub shafts 13a are displaced forward corresponding to the displacement of the stub shafts 13b (the second coupling member 16). That is, the first coupling members 14 pivot forwardly.

Accordingly, the anvil 6 pivots about the stub shafts 13a and 13b and tilts with respect to the cartridge 5, thus moving forwardly corresponding to the angle of rotation of the first coupling members 14. [0039] Fig. 9 is a sectional view of the parallel closing mechanism, showing its operation subsequent to the sequence of steps described above with reference to Fig. 8. The closing pipe 4 is further slid forward from the position shown in Fig. 8. The pin 4b lies at substantially the highest position in the groove 16c. The projection 16b disengages from the hole 4a and is received in the closing pipe 4. The first coupling members 14, the second coupling member 16 and the anvil 6 continue the movement described above in connection with Fig. 8. At this time the stub shafts 16a lie in the curved, elongated grooves 12b substantially intermediately thereof. [0040] Fig. 10 is a sectional view of the parallel closing mechanism, showing its operation subsequent to the sequence of steps described above in respect of Fig. 9. The closing pipe 4 is further slid forward from the position shown in Fig. 9. The pin 4b disengages from the groove 16c and rides on the top of the second coupling member 16. Accordingly, the pin 4b depresses the second coupling member 16. The first coupling members 14, the second coupling member 16 and the anvil 6 continue the movement described above with respect to Figs. 8 and 9. [0041]

Fig. 11 is a sectional view of the parallel closing mechanism, showing its operation to reach the full-closed position subsequent to the sequence of steps described above with reference to Fig. 10. The closing pipe 4 is further slid forward from the position shown in Fig. 10. The pin 4b is inhibited by the stopper 16d from forward movement, and presses the second coupling member 16 forward while depressing it. The depression of the second coupling member 16 by the pin 4b prevents the anvil 6 from opening due to a load or the like by the staple firing operation. At this time the stub shafts 16a are displaced to substantially the foremost position in the curved, elongated grooves 12b, and the second coupling member 16 also pivots forward while rotating with respect to the cartridge 5. The first coupling members 14 are pulled into the grooves 16e cut in the back of the second coupling member 16, and the stub shafts 13b engage in the recesses 14b (see Fig. 4). While in the actual use, the cartridge 5 and the anvil 6 firmly hold therebetween the body tissue 44 as shown in Fig. 5. [0042] As the parallel closing mechanism operates step by step in the order of

Figs. 7 to 11, the second coupling member 16 approaches the first coupling members 14, and consequently the distance L2 between the stub shafts 14a and 16a gradually decreases. Since the distance "Ll between the stub shafts 13a and 13b is fixed, the decrease of the distance L2 causes the anvil 6 to turn to the position parallel to the cartridge 5. [0043]

On the other hand, to shift the anvil 6 from the closed position to the full-open position (the initial state), the above-described operation is reversed in sequence, that is, the closing procedure is reversed in the order of Figs. 11 to 7. By backward sliding movement of the closing pipe 4, the pin 4b moves backward on the top of the second coupling member 16 (Figs. 11 to 9) and engages in the groove 16c, pulling the second coupling member 16 backward (Figs. 8 and 7). As the stub shafts 16a are displaced along the curved, elongated groove 12b toward the rearmost potion while rotating, the second coupling member 16 also pivots backward to the initial position. Since the distance Ll between the stub shafts 13a and 13b is fixed, the first coupling members 14 also pivot backward.

The anvil 6 supported by the first coupling members 14 rises upwardly and moves back corresponding to the angle of pivoting of the first coupling members 14. [0044]

The parallel closing mechanism of the stapling instrument utilizes a four-joint link mechanism. More specifically, the first coupling members 14 correspond to a crank for rotating motion, and the second coupling members 16 correspond to a lever for reciprocating motion. The anvil 6 corresponds to a connecting rod which transmits movements of the first and second coupling members 14 and 16 to each other, and the cartridge holder 12 corresponds to a fixed frame. [0045] Next, a description will be given, with reference to Figs. 3, 6 and 12, of an operating mechanism of the stapling instrument 1. Fig. 12 is an exploded perspective view showing the handle portion and its vicinity of the stapling instrument depicted in Fig. 2.

The knife 20 has at its distal end an edge serving as a cutting blade. On the side opposite to the edge of the knife 20,. that is, on the end portion of the knife 20 proximal to the handle portion 3 there is disposed the cam bar adaptor 23. The cam bar adaptor 23 is connected to the end portions of the knife 20 and the cam bar 21 proximal to the handle portion 3. The end portion of the cam bar adaptor 23 proximal to the handle portion 3 is connected to a cam bar rack 24, and the cam bar rack 24 has in the top of the other end portion thereof a groove 15 engageable with a lock lever 43. The cam bar rack 24 has a toothed portion 24a in the underside of its intermediate portion, and the toothed portion 24a meshes with a gear 25. [0046] The gear 25 includes a small-radius gear section 25a which rotates tlierewith coaxially, and tlie small gear section 25a meshes with a toothed portion 26a formed in the underside of the forward portion of a firing rack 26. The firing rack 26 has in the underside of its rearward portion another toothed portion 26b, which meshes with a toothed sector portion 27a provided in the top of the staple firing lever 27. The staple firing lever 27 has its lever portion projected out from substantially a disk-shaped plate journaled centrally thereof, and is pivotable about a pin 28b fixed to a casing 28 of the handle portion 3. one portion of the upper peripheral surface of the disk-shaped portion forms the above-mentioned toothed sector portion 27 a. The staple firing lever 27 is always pressed in the direction to move away from the handle grip, by a coiled spring 30 mounted around the pin 28b (see Fig. 3). [0047]

The handle portion 3 and the insert section 2 are fixedly joined to each other by a tubular cap 31 pivotably mounted on the casing 28. The closing pipe 4 extends through the cap 31 centrally thereof and into the handle portion 3. The end portion of the closing pipe 4 proximal to the handle portion 3 is linked to a slider 32. The slider 32 is always pressed toward the handle portion 3 by a spring 29 disposed between the cap 31 and the slider 32 (see Fig. 3). The slider 32 is linked by a pin at the other end to a coupling member 34, and the coupling member 34 is linked by a pin to the closing lever 40. [0048]

The closing lever 40 is pivotable about a pin 28a fixed to the casing 28 of the handle portion 3. The pin 28a is disposed at the same position as the pin 28b having fixed thereto the staple firing lever 27, but the pin 28a is not directly linked to the staple firing lever 27; the closing lever 40 and the staple firing lever 27 are pivotable independently of each other.

The closing lever 40 comprises a cam section having first and second cam faces 40a and 40b, and a lever section projecting in a direction substantially opposite to the cam section. The first and second cam faces 40a and 40b of different shapes are arranged on the cam section at outside and inside thereof, respectively. The first cam face 40a engages with a pre-release button 41, whereas the second cam face 40b engages with the release button 42. [0049]

The pre-release button 41 is pivotably held by a pin 28c placed in the casing 28. The distal end portion of the pre-release button 41 engages in an arcuate recess made in the first cam face 40a. Provision is made to allow the other end portion of the pre_rrelease button 41 to project out of the casing 28, forming an actuator surface for pressing by a user for operation. [0050]

The intermediate portion of the release button 42 is pivotably held by the pin 28c having fixed thereto the pre-release button 41. Though journaled on the same pin 28c, the pre-release button 41 and the release button 42 are adapted to be movable independently of each other. A notch in the forward portion of the release button 42 engages with substantially a similar-shaped notch made in the second cam face 40b of the closing lever 40. As is the case with the pre-release button 41, the other end of the release button 42 is configured to allow its other end to project out of the casing 28, forming an actuator surface for pressing by the user.

The notch in the second cam face 40b is, properly speaking, U-form in cross section, and when the notch in the forward portion of the release button 42 engages the U-shaped notch centrally thereof, the other end portion of the release button 42 projects out of the casing 28 for pressing by the user. However, when the closing lever 40 turns to the right or left and the notch of the release button 42 goes out of engagement with the U-shaped notch accordingly, the other end portion of the release button 42 does not project out of the casing 28, inhibiting operation. [0051] The lock lever 43 is pivotably held by the pin 28c which is fixed to the casing 28 and on which the pre-release button 41 is journaled. The lock lever 43 is fitted in a recess 41a made in the inner side of the pre-release button 41 in the longitudinal direction of the pin 28c. The lock lever 43 and the pre-release button 41 are allowed to move independently of each other. One end of the lock lever 43 forms a projection for engagement with the groove 15 of the cam bar rack 24, and the other end abuts against one inner side of the recess 41a of the pre-release button 41. Further, though not shown, a plate spring is disposed between the inside of the recess 41a of the pre-release button 41 and the lock lever 43, which the lock lever 43 is pressed toward the groove 15.

When the pre-release button 41 is in an actuatable position where its other end projects out of the casing 28, the other end of the lock lever 43 abuts against one inner side of the recess 41a of the pre-release button 41, bringing one end of the lock lever 43 out of engagement with the groove 15. [0052]

The casing 28 includes a handle grip 46; the grip 46, the lever section of the closing lever 40 and the lever section of the staple firing lever 27 are arranged in this order in the direction from the handle portion 3 to the insert section 2.

When the anvil 6 becomes full-closed with respect to the cartridge 5, the tip end portion of the pre-release button 41 turns to the right and the upper projection of the lock lever 43 abuts against the inside of the recess of the pre-release button 41, and consequently the lock lever 43 also turns to the right and one end of the lock lever 43 goes out of engagement with the groove 15. [0053]

Next, the operation of the stapling instrument 1 will be described with reference to Figs. 3, 4, 13 and 14. As shown in Fig. 3, the anvil 6 is full-open with respect to the cartridge 5 and the closing lever 40 and the staple firing lever 27 stay apart from the grip 46. The insert section 2 of the stapling instrument I₃ held in this state, is inserted into a patient's body. An affected part is confirmed first, followed by moving the distal end portion of the insert section 2 to an ablation site, and by squeezing the closing lever 40 against the grip 46. At this time, the stub shafts 16a of the second coupling member 16 lie at the rearmost position in the curved, elongated groove 12b. [0054]

Fig. 13 shows in section the stapling instrument of Fig. 2 in the course of its operation for closing the anvil 6 with respect to the cartridge 5. When squeezed toward the grip, the closing lever 40 turns about the pin 28a fixed to the casing 28. A coupling member 34 linked by a pin to the cam section in the vicinity thereof is pushed in a direction toward the insert section 2. The closing pipe 4 linked to the coupling member 34 through the slider 32 is also pushed out in the direction toward the insert section 2. The closing pipe 4 thus pushed out forwardly presses the second coupling member 16 while pressing it down with the pin 4b. [0055]

The second coupling member 16 thus pressed advances a little while pivoting, through forward movement of the stub shafts 16a along the curved, elongated grooves 12b. Since the distance Ll between the stub shafts 13a and 13b is fixed, the first coupling member 14 pivots about the stub shafts 14a as if falling down forward. The anvil 6 is linked to the first and second coupling members 14and 16, and hence it goes down from above to the closed position parallel to the cartridge 5 while at the same time somewhat advancing. [0056]

Fig. 14 is a sectional view of the stapling instrument of Fig. 2, showing the state in which the anvil 6 is full-closed with respect to the cartridge 5. Squeezing the closing lever 40 further toward the grip from the position shown in Fig. 13, the stub shafts 16a are displaced to substantially the foremost position in the curved, elongate grooves 12b, pivoting the second coupling member 16 to a horizontal position. At the same time the first coupling members 14 also pivot forwardly, bringing the anvil 6 linked to the first and second coupling members 14 and 16 into parallel closed relation to the cartridge 5. While in actual use, the body tissue is held between the anvil 6 and the cartridge 5 (see Fig. 5).

When squeezed against the grip to the rearmost position, the closing lever 40 is. locked, allowing the staple firing lever 27 to operate. By squeezing the staple firing lever 27 against the grip, staples are driven into the affect part of the body tissue. At the same time, the knife 20 advances along the afore-mentioned knife slot and the guide groove 9, cutting the body tissue 44 along a center line between the staple rows (see Figs. 4 and 5). [0057]

As described above, according to Embodiment 1, the use of the four-joint link mechanism enables the anvil 6 to go down to the closed position parallel to the cartridge 5 to firmly hold the body tissue between the cartridge 5 and the anvil 6, achieving stable stapling.

The configuration of this embodiment minimizes the mechanism for actuating, the anvil 6, and hence it minimizes the diameter of the closing pipe 4 accordingly, making it possible to offer the stapling instrument 1 that permits the use therewith of a thin trocar.

By supporting the anvil 6 with two parts of the first and second coupling members 14 and 16, the attitude of the anvil 6 is controlled.

Since the second coupling member 16 does not simply rotate but instead the stub shafts 16a are displaced along the curved, elongated grooves

12b, the anvil 6 is allowed to close with respect to the cartridge 5 in parallel relation thereto in the later half of the closing operation. The parallel closing of the anvil 6 with respect to the cartridge 5 produces a large amount of grasping force, preventing the body tissue from sliding between the cartridge and the anvil and hence firmly holding therebetween the body tissue during stapling.

Furthermore, riding of the closing pipe 4 on the second coupling member 16 prevents the distance (gap) between the anvil 6 and the cartridge 5 from increasing due to a load by stapling. [0058]

EMBODIMENT 2

A description will be given below of Embodiment 2 of the present invention.

The stapling instrument of Embodiment 2 utilizes a four-joint parallel link mechanism. Fig. 15 is a sectional view explanatory of the operation of the parallel closing mechanism of the stapling instrument according to

Embodiment 2, showing its full-open state (initial state). Fig. 16 is an exploded perspective view showing the distal end portion of the insert section

2 and its vicinity in the stapling instrument 1 of Fig. 15. Incidentally, since the configurations and operations of the parts of the insert section 1 in Fig. 16 are almost the same as in the stapling instrument of Embodiment 1, except only differences mentioned below.

[0059] ^{•■ • ■}

In the stapling instrument 1 depicted in Figs. 15 and 16, the cartridge holder 12 has in either of its side walls an elongated groove 12c in place of the curved, elongate groove 12b shown in Fig. 4. Another difference is the provision of a notch 12d formed somewhat below but contiguous to the distal end portion of the elongated groove 12c. The notch 12d is to receive the stub shaft 16a of the afore-mentioned second coupling member 16 when it is displaced to the distalmost position in the elongated groove 12c. [0060]

Referring next to Figs. 17 through 21, a description will be given of the operation of the parallel closing mechanism of the stapling instrument 1.

Figs. 17 to 21 illustrate, in section, a sequence of steps involved in the (parallel closing) operation of the parallel closing mechanism from the full-open position to the full-closed position. Fig. 17 is a sectional view showing the operation of the parallel closing mechanism in the full-open position (the initial position). For easy understanding, the second coupling member 16 is shown in side elevation, not in section. [0061]

In the initial state shown in Fig. 17, the pin 4b engages in the groove 16c and the projection 16b engages in the hole 4a. The first coupling members 14 pivot about the stub shafts 14a. Since the closing pipe 4 is pressed backward, the pin 4b also presses the projection 16b backward. As the result of this, the anvil 6 linked to the second coupling member 16 and the first coupling members 14 linked to the anvil 6 are also pressed backward. The first coupling members 14 linked to the anvil 6 rise upwardly, bringing the latter to the full-open position as shown. At this time the stub shafts 16a each lie at the rearmost end of the elongated groove 12c. [0062]

Fig. 18 is a sectional view of the parallel closing mechanism, showing its operation subsequent to the sequence of steps described above with reference to Fig. 17. In the first place, the closing pipe 4 is pushed forward. At the same time, the pin 4b presses the inner wall of the groove 16c on the side nearer to the anvil 6, and hence presses the second coupling member 16 forwardly. At the same time, the stub shafts 16a are displaced along the grooves 12c while rotating. As a result, the second coupling member 16 tilts forwardly while advancing.

Accordingly, the anvil 6 pivots about the stub shafts 13a and 13b and tilts with respect to the cartridge 5, thus moving forwardly corresponding to the angle of rotation of the first coupling members 14. At this time, the stub shafts 16a each lie in the elongated groove 12c substantially intermediately thereof.

[0063]

Fig. 19 is a sectional view of the parallel closing mechanism, showing its operation subsequent to the sequence of steps described above with reference to Fig. 18. The closing pipe 4 is further slid forward from the position shown in Fig. 18. The Positional relationship between the pin 4b and the groove 16c is the same as in Fig. 18. The projection 16b partly engages in the hole 4a and somewhat goes down into the closing pipe 4. The first coupling members 14, the second coupling member 16 and the anvil 6 continue the movement described above in connection with Fig. 18. The stub shafts 16a are each displaced to the foremost end of the elongated grooves 12c and, at the same time, somewhat goes down into and engages in the notch 12d. At this time, the stub shafts 13a, 13b and the stub shafts 14a, 16a form a parallelogram. And, since in the parallelogram the side joining the stub shafts 13a and 13b and the side joining the stub shafts 14a and 16a are parallel with each other, the anvil 6 also becomes parallel with the cartridge holder 12 (the cartridge 5).

Thereafter, the first and second coupling members 14 and 16 tilt (pivot) forwardly the same angle at one time about the stub shafts 14a and 16a, respectively. This produces the same torque for the first and second coupling members 14 and 16. [0064]

Fig. 20 is a sectional view of the parallel closing mechanism, showing its operation subsequent to the sequence of steps described above with reference to Fig. 19. The closing pipe 4 is slid further forward from the position in Fig. 19. The pin 4b partly engages in the groove 16c and, at the same time, it presses the second coupling member 16 forwardly.

Since the stub shafts 16a each engage in the notch 12d, the second coupling member 16 is inhibited from further advancing; instead, it further pivots forwardly. At the same time, the first coupling members 14 also pivot the same angle as does the second coupling member 16. The anvil 6 linked to the first and second coupling members 14 and 16 descend toward (approach) the cartridge 5 while remaining in parallel with each other. [0065]

Fig. 21 is a sectional view of the parallel closing mechanism, showing its operation subsequent to the sequence of steps described above with reference to Fig. 20, showing the full-closed state. The closing pipe 4 is slid further forward from the position in Fig. 20. The pin 4b presses the second coupling member 16 forward as in the case of Fig. 20.

Since the stub shafts 16a each engage in the notch 12d, the second coupling member 16 further pivots and ultimately it becomes parallel with the cartridge holder 12. Simultaneously with this, the first coupling members 14 also pivot the same angle as does the second coupling member 16. In this instance, the tip end portions of the second coupling member 16 engage in depression-like curved portions 14c made in the rear end portions of the first coupling members 14 (see Fig. 16).

The anvil 6 is brought down into adjacent but slightly spaced relation to the surface of the cartridge 5. In the actual use, the cartridge 5 and the anvil 6 firmly hold therebetween the body tissue 44 as shown in Fig. 5.

Since the second stub shafts 16a each engage in the notch 12d, it is possible to prevent the anvil 6 from opening due to a load or the like by staple firing operation. [0066] As the parallel closing mechanism operates step by step in the order of

Figs. 7 to 19, the second coupling member 16 approaches the first coupling members 14, and consequently the distance L2 between the stub shafts 14a and 16a gradually decreases. Since the distance Ll between the stub shafts 13a and 13b is fixed, the decrease of the distance L2 causes the anvil 6 to turn to the position parallel to the cartridge 5. At the time of the operation in Fig. 19, the distance Ll is equal to L2 and a parallelogram with vertexes at the stub shafts 13a, 13b and the stub shafts 14a 16a is formed; as the parallelogram pivots forward in the order of Figs. 19 to 21, the anvil 6 gradually closes with respect to the cartridge 5 in parallel. [0067]

The states of Figs. 19 to 21, that is, the states of maintaining the parallelism of the parallelogram but changing only its angle (angle of pivoting) correspond to the four-joint parallel link mechanism. Accordingly, at the stages of operation shown in Figs. 19 to 21 the torques of the first and second coupling members 14 and 16 are equal to each other, allowing the anvil 6 to press the cartridge 5 with uniform force. [0068]

The point in time when the stub shaft 16a engages in the notch 12d will hereinafter be referred to as the starting point, and the point in time when the anvil 6 becomes full-closed with respect to the cartridge 5 will hereinafter be referred to as the ending point. The parallel closing mechanism is configured such that the angle of forward pivotal movement of the first coupling member 14 (the stub shaft 14a) and the second coupling member 16 (the second stub shaft 16a) throughout the operation from the starting point to the ending point is equal to or smaller than 20°. On this account, the amount of displacement of the anvil 6 with respect to the cartridge 5 is small, lowering the degree of scraping the body tissue held between them. The above-mentioned angle of pivoting may preferably be equal to or smaller than 15°. [0069]

On the other hand, to shift the anvil 6 from the closed position to the full-open position (the initial state), the above-described operation is reversed in sequence, that is, the closing procedure is reversed in the order of Figs. 21 to 17. By backward sliding movement of the closing pipe 4, the pin 4b engages in the groove 16c, pulling the second coupling member 16 backward. As the stub shafts 16a are each displaced along the elongated groove 12c toward the rearmost potion while rotating, the second coupling member 16 also pivots backward to the initial position. Since the distance Ll between the stub shafts 13a and 13b is fixed, the first coupling members 14 also pivot backward.

The anvil 6 supported by the first coupling members 14 rises upwardly and moves back corresponding to the angle of pivoting of the first coupling members 14. [0070]

Next, a description will be given of a method for measuring the body tissue grasping force of the stapling instrument and measured values.

The measurement begins with squeezing the closing lever 40 of the stapling instrument to the rearmost position adjacent the handle grip and locking the lever at that position. In this case, the anvil 6 becomes full-closed with respect to cartridge 5 as shown in Fig. 21.

The next step is to fasten the cartridge holder 12 to a jig, leaving the anvil 6 non-fastened.

This is followed by gradually applying a tensile load on the full-closed anvil 6 in a direction in which to open it with respect to the cartridge 5. Since the anvil 6 is non-fastened, it gradually opens in accordance with the magnitude of the tensile load. And, the opening of the anvil 6 with respect to the cartridge 5 is measured corresponding to increased tensile load. [0071] Fig. 22 is a table showing measured grasping force of the stapling instrument according to Embodiment 2. Let P [kgfj represent the tensile load placed on the anvil in the direction in which to open it with respect to the cartridge 5.

Let S [mm] represent the gap between the anvil 6 and the cartridge 5 when the tensile load P is applied. The gap S is 0 mm when the anvil is full-closed, and it increases with an increase in the load P.

Let S' [mm] represent the opening of the anvil from its horizontal position when the tensile load P is applied. The horizontal position of the anvil 6 with respect to the cartridge 5 is taken to be the reference (+0 mm) of the opening S¹. Incidentally, let it be assumed that when in its full-open position the anvil 6 be inclined toward the cartridge 5 by 2.20 mm (opening S¹ = -2.20 mm) from the horizontal position. In other words, assume that when the anvil 6 and the cartridge 5 are both horizontal, the gap S between them is 2.20 mm. [0072]

As shown in Fig. 22, even if the anvil 6 is pulled at the tip end portion with a tensile load P = IO kgf, the anvil 6 is inclined 0.05 mm (opening S' = -0.05 mm) toward the cartridge 5 from the horizontal position. That is to say, the measured results indicate that even when the anvil 6 is horizontal with respect to the cartridge 5, the stapling instrument used for measurement produces a grasping force of 10 kgf.

Incidentally, the data shown in Fig. 22 is an example of the grasping force of the stapling instrument according to Embodiment 2 and does not define the grasping force of the stapling instrument according to the present invention. [0073]

As described above, Embodiment 2 produces, in addition to the effect of Embodiment 1, an effect that the use of the four-joint parallel link mechanism provides a uniform distribution of force for pressing the cartridge 5 by the anvil 6 and hence produces a sufficient amount of grasping force to prevent slipping of body tissue between the cartridge and the anvil, firmly holding the body tissue during stapling.

Moreover, since the degree of scraping the body tissue lowers between the anvil 6 and the cartridge 5 during the parallel closing operation, damage to the body tissue can be reduced. [0074]

While the stapling instrument of the present invention has such a configuration as described above, the parallel closing mechanism may be applied to various other stapling instruments as well. It is also applicable, for example, to a stapling instrument with no knife or similar ablation mechanism. [0075]

Either one of the first coupling members 14 may be removed, or it may also be modified to such a one-piece symmetrical structure like the second coupling member 16.

Conversely, the second coupling member 16 can also be configured as two separate structures like the first coupling members 14. [0076]

The curved, elongated grooves 12b or elongated grooves 12c are not limited specifically to such forms, but they may also be of other forms such as an oblique line and a sine curve.

In such an instance, to effectively prevent body tissue from slipping to the distal end of the anvil 6, it is also possible to close the anvil 6 with respect to the cartridge 5 with its distalmost end first by changing the form of the curved, elongated grooves 12b or elongated grooves 12c accordingly.

Furthermore, by newly forming (curved) elongated grooves in the cartridge holder 12 for engagement with the stub shafts 14a of the first coupling shafts 14, it is also possible to displace the first coupling members 14 along the (curved) elongated grooves. [BRIEF DESCRIPTION OF THE DRAWINGS] [0077]

[Fig. 1] Perspective view of the whole structure of a conventional stapling instrument.

[Fig. 2] Perspective view of the whole structure of a stapling instrument according to Embodiment 1 of the present invention. [Fig. 3] Sectional view of Hie stapling instrument 1 of Fig. 2, with an anvil 6 full-open with respect to a cartridge 5.

[Fig. 4] Exploded perspective view showing parts surrounding the distal end portion of an insert section 2 of the stapling instrument 1 of Fig. 2. [Fig. 5] Enlarged sectional view showing stapling of body tissue by use of the stapling instrument 1 of Fig. 2.

[Fig. 6] Exploded perspective view showing parts surrounding the insert section 2 of the stapling instrument 1 of Fig. 2.

[Fig. 7] Sectional view explanatory of the operation of a parallel closing mechanism of the stapling instrument according to Embodiment 1, showing its full-open state (initial state).

[Fig. 8] Sectional view explanatory of the operation of the parallel closing mechanism subsequent to the operation in Fig. 7.

[Fig. 9] Sectional view explanatory of the operation of the parallel closing mechanism subsequent to the operation in Fig. 8.

[Fig. 10] Sectional view explanatory of the operation of the parallel closing mechanism subsequent to the operation in Fig. 9.

[Fig. 11] Sectional view explanatory of the operation of the parallel closing mechanism subsequent to the operation in Fig. 10, showing its full-closed state.

[Fig. 12] Exploded perspective view showing parts surrounding a handle portion 3 of the stapling instrument 1 of Fig. 2.

[Fig. 13] Sectional view of the stapling instrument 1 of Fig. 2 in the course of closing of the anvil 6 with respect to the cartridge 5. [Fig. 14] Sectional view of the stapling instrument 1 of Fig. 2 with the anvil 6 in the full-closed position with respect to the cartridge 5.

[Fig. 15] Perspective view of the whole structure of a stapling instrument according to Embodiment 2.

[Fig. 16] Exploded perspective view showing parts surrounding the distal end portion of an insert section 2 of the stapling instrument 1 of Fig. 15. [Fig. 17] Sectional view explanatory of the operation of a parallel closing mechanism of the stapling instrument according to Embodiment 2, showing its full-open state (initial state).

[Fig. 18] Sectional view explanatory of the operation of the parallel closing mechanism subsequent to the operation in Fig. 17.

[Fig. 19] Sectional view explanatory of the operation of the parallel closing mechanism subsequent to the operation in Fig. 18.

[Fig. 20] Sectional view explanatory of the operation of the parallel closing mechanism subsequent to the operation in Fig. 19. [Fig. 21] Sectional view explanatory of the operation of the parallel closing mechanism subsequent to the operation in Fig. 20, showing its full-closed state.

[Fig. 22] Table showing measured results of grasping force of the stapling instalment according to Embodiment 2. [Explanations of Letters or Numerals] [0078]

1 : Stapling Instrument 2: Insert Section 3: Handle Portion 4: Closing lever 4a, 12a: Hole 4b: Pin 5: Cartridge

5a: Engaging projection 6: Anvil 6a: Guide 7: Staple

8: Staple Storage Magazine 9: Guide Groove 10: Staple Hold Member 11, 15, 16e: Groove

12: Cartridge Holder

12b: Curved, elongated Groove

12c, 16c: Elongated Groove 12d, 12e: Notch

13a, 13b: Stub shaft

14: First Coupling Member

14a, 16a: Stub shaft

14b, 41a: Recess 14c: Curved portion

16: Second Coupling member

16b: Projection

16d: Stopper

20: Knife 21: Cam Bar

23: Cam Adaptor

24: Cam Bar Rack

24a, 26a, 26b, 27a: Teeth

25: Gear 25a: Small-Radius Gear Section

26: Firing Rack

27: Staple Firing Lever

28: Casing

28a, 28b, 28c: Pin 29: Spring

30: Coiled Spring

31: Cap

32: Slider

34: Coupling Member 40: Closing Lever 40a: First Cam Face

40b: Second Cam Face

41 : Pre-Release Button

42: Release Button

43 : Lock Lever

44: Body Tissue

46: Grip

Ll: Distance between 13a and 13b

L2: Distance between 14a and 16a

Claims

CLAIMS [Claim 1]

A stapling instrument which is provided with an insert section, and a handle portion connected to said insert section and having an anvil actuating means and a staple firing means, wherein said insert section includes: an anvil which opens and closes with respect to a cartridge having housed therein staples; a cartridge holder which holds said cartridge; a first coupling member which is linked at one end to said cartridge holder by engagement therewith of a first stub shaft disposed at said one end of said first coupling member through a hole and is linked at the other end to said anvil through a first coupling portion; a second coupling member which is linked to said cartridge holder by engagement of a second stub shaft disposed at one end of said second coupling member with a groove made in said cartridge holder and which is linked at the other end to said anvil through a second coupling portion; and a closing pipe linked to said anvil actuating means and disposed behind said cartridge holder and slidable back and forth; wherein upon operating said anvil actuating means, said closing pipe slides to press said second coupling member forward, then said second coupling member thus pressed moves along said groove while pivoting, then said first coupling member pivots forwardly about said first stub shaft, and said anvil linked to said first and second coupling members closes with respect to said cartridge in parallel thereto.

[Claim 2]

The stapling instrument of claim 1. wherein the distance between said first coupling portion and said first stub shaft and the distance between said second coupling portion and said second stub shaft are equal to each other; and when said anvil is full-closed with respect to said cartridge, the distance between said first coupling portion and said second coupling portion and the distance between said first stub shaft and said second stub shaft are equal to each other, and said first coupling portion, said second coupling portion, said first stub shaft and said second stub shaft form vertexes of a parallelogram.

[Claim 3]

The stapling instrument of claim 2, wherein a notch is made in the foremost portion of said groove of said cartridge holder; and when said anvil is full-closed with respect to said cartridge, said second stub shaft engages in said notch.

[Claim 4]

The stapling instrument of claim 3, wherein the angle of pivoting of said second stub shaft from the position where said second stub shaft engages in said notch to the position where said anvil becomes full-closed with respect to said cartridge is equal to or smaller than 20°.

[Claim 5]

The stapling instrument of claim 1, wherein said closing pipe has a hole in the top of its forward portion; and a projection provided on said second coupling member engages in said hole.

[Claim 6]

The stapling instrument of claim 5, wherein said closing pipe has a pin disposed at the forward part of said hole in a direction perpendicular to the axis of said closing pipe; and said pin engages in a groove cut in forward of said projection of said second coupling member. [Claim 7]

The stapling instrument of claim 1, wherein a cam bar extended from said handle portion toward said insert section is linked to said staple firing lever; and upon actuation of said staple firing means, said cam bar pushes up a staple hold member disposed near a staple storage magazine in said cartridge to thereby fire a staple. [Claim 8]

The stapling instrument of claim 7, wherein a knife extended from said handle portion toward said insert section is linked to said staple firing means, together with said cam bar; and upon actuation of said staple firing means, said knife slides forward. [Claim 9]

The stapling instrument of claim 1, wherein said anvil has on both side surfaces thereof downward projecting guides; and when said anvil is in a closed position with respect to said cartridge, said guides lie on both sides of said cartridge holder.