Ratchet-driven Cartridge For Surgical Instruments

Abstract

A disposable staple-housing cartridge adapted for mounting on a surgical instrument and particularly suited for stapling skin and fascia. The cartridge comprises, basically, a stationary sawtooth staple-retaining member, a sawtooth staple-driving member mounted for reciprocating movement, an anvil, and a staple pusher. For each reciprocation of the staple-driving member, each of the staples housed in the cartridge is driven forward from one tooth to the next successive tooth of the retaining member. The pusher element controls the movement of the reciprocating drive member, advances each of the staples, ejects a staple from the cartridge and bends the ejected staple around the anvil; this occurs for each drive cycle of the pusher. The pusher is, in turn, operated by the associated surgical instrument.

Description

BACKGROUND OF THE INVENTION

While the use of stainless steel staples in surgical procedures has been practiced for a number of years, it has only been a very short time since the development of an efficient instrument and cartridge for effecting the stapling of the skin of a surgical patient. See copending U.S. Pat. application Ser. No. 852,822, filed on Aug. 25, 1969, and assigned to the present assignee. And, since the initial effort in providing a stapler useful for suturing the skin of a surgical patient, two further efforts have been made to improve and simplify both the disposable cartridge and the instrument itself. See copending U.S. Pat. application Ser. No. 14,614, filed on Feb. 26, 1970, and copending U.S. Pat. application Ser. No. 21,465, filed on Mar. 20, 1970, each assigned to the present assignee.

In the first of the above-referenced copending U.S. patent applications, there are disclosed a gas-powered surgical instrument and a disposable staple-carrying cartridge unit adapted to be mounted on the instrument. In that application, a plurality of staples are guided and are driven by a pair of helical screws forming a part of the cartridge. The basic instrument is provided with a complex gearbox arrangement for rotating the helical screws, thereby advancing the staples. The complexity and the cost of such an arrangement should be immediately apparent.

In the second of the above-noted copending U.S. patent applications, two improved cartridge arrangements are disclosed. However, each of these arrangements carries forth the principle of using helical screws for advancing and guiding the staples and the use of a complex gearbox for perfecting the rotation of the screws.

In the third of the above-noted copending U.S. patent applications, a cartridge is disclosed which results both in the simplification and in the reduction of costs involved in practicing the known stapling techniques. In this cartridge, helical screws are still used for advancing and guiding the staples. However, the complex gearbox arrangement is eliminated from the basic instrument and is replaced by a simple helical cam, integral with each staple-advancing screw. Therefore, by the teachings in the last of the three copending patent applications, the basic instrument is relieved of the functions of both ejecting the staples and rotating the staple-advancing screws; the basic instrument needs only perfect the ejection of the staples, the screw rotation being simply, efficiently and economically carried out in the cartridge.

Notwithstanding the many advances in the surgical stapling art, referred to above, there remain areas wherein improvement and redesign are desirable. It is toward the advancement of the prior art described immediately above that the present invention is directed.

SUMMARY OF THE INVENTION

The present invention relates to a disposable staple-carrying cartridge particularly suited for suturing skin and fascia and adapted to be mounted on an instrument having only rectilinear thrust capabilities. The inventive cartridge brings about the staple advancement operation by the interaction of a U-shape sawtooth retaining member fixedly mounted in the cartridge housing and a U-shape sawtooth staple-driving member mounted on the retaining member for reciprocal motion. The retaining and driving members, mounted in the housing, associate with a plurality of staples preferably equal in number to the number of teeth in the movable driving member. A pusher, slidably mounted in the housing, controls the operation of the movable driving member; a drive bar in the basic instrument controls the operation of the pusher.

When the forward thrust of the pusher is initiated by the basic surgical instrument, the movable driving member travels forward a distance somewhat greater than the common length of the teeth in the retaining member and in the driving member. At this occurrence, each of the staples housed in the cartridge is advanced by the same distance, each traveling from one tooth to the next successive tooth in the retaining member. After the staples have so moved, the driving member comes into contact with a stop, becomes free from the pusher, and allows the pusher to continue its forward motion, eject and form a staple in the skin of a patient. At this occurrence, the return stroke begins.

The basic instrument, after the stapling operation, returns the pusher to its retracted position, and, because the pusher associates with the driving member, the latter is also returned to its retracted position. Then, the cartridge is ready for another firing operation.

From the above, the simplicity of the inventive staple-housing cartridge should be evident. The staples are housed, advanced and discharged with a minimum effort and with a minimum number of moving parts. At the same time, however, the cartridge operation is both reliable and efficient.

Accordingly, it is the main object of the present invention to provide a simplified disposable cartridge adapted to be mounted on a surgical instrument having only rectilinear thrust capabilities, and being particularly suited for stapling skin and fascia.

It is a further object of the present invention to provide a disposable staple-carrying cartridge having a minimum number of movable parts and yet being both reliable and efficient.

It is a further object of the present invention to provide a disposable staple-carrying cartridge wherein staples are advanced by means of a novel and simple sawtooth arrangement.

These and other objects of the present invention, as well as many of the attendant advantages thereof, will become more readily apparent when reference is made to the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of the disposable staple-carrying cartridge forming a part of the present invention;

FIG. 2 is a partial side view of the inventive cartridge during the staple-advancing operation;

FIG. 3 is a view similar to FIG. 2 but showing the cartridge during its return stroke;

FIG. 4 is a partial cross section of the inventive staple-housing cartridge in its fully retracted position;

FIG. 5 is a view similar to FIG. 4 but showing the cartridge during the staple-advancing operation;

FIG. 6 is a view similar to FIG. 5 but showing the cartridge at the end of the staple advancing and forming operations;

FIG. 7 is a top view, partially in section, of the inventive cartridge illustrated in FIG. 6;

FIG. 8 is a cross section of the cartridge taken along line 8--8 of FIG. 6; and

FIG. 9 is a cross section of the cartridge taken along line 9--9 of FIG. 6.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference first to FIG. 1, the construction of the inventive staple-carrying cartridge will be described. The cartridge is shown generally at 10 and comprises a lower casing 12, an upper casing 14, a flexible U-shape retaining member 16, a flexible U-shape driving member 18, and a pusher 20. A single staple is shown at 22.

As seen in FIGS. 1 and 8, the lower casing 12 defines a hollow bounded by a front wall 24, a rear wall 25, a pair of sidewalls 26 and a bottom wall 28. On the top of each sidewall 26, there is present a staple guide surface 30 terminating in a ramp 32. The ramps 32 are positioned at the front of the cartridge 10 adjacent the front wall 24 of the lower casing 12.

As best seen in FIGS. 8 and 9, the bottom wall 28 of the lower casing 12 is provided with a pair of upstanding rails 34 defining therebetween, a mounting track 35. Rails 34 extend substantially the entire length of the casing 12. And, as seen best in FIGS. 1, 8 and 9, a guide bar 36 projects from the bottom of the U-shape retaining member 16, the guide 36 extending substantially the entire length of the retaining member. The interaction between the mounting track 35 and the guide bar 36 maintains the bottom of the retaining member 16 in a fixed and central position with respect to the lower casing 12. The length of the retaining member 16 is made substantially equal to the length of the hollow in the lower casing 12 and, therefore, there is no longitudinal motion of the retaining member in the lower casing.

The U-shape driving member 18 is adapted to slide in its longitudinal direction, along the U-shape retaining member 16. For this purpose, the retaining member is provided with a pair of upstanding rails 38, defining a guide track 39, and the driving member is provided with a guide bar 40. The rails 38 extend substantially the entire length of the retaining member 16, and the guide bar 40 extends substantially the entire length of the driving member 18.

A plurality of retaining teeth 42 are defined in the upstanding arms 44 of the U-shape retaining member 16. Similarly, a plurality of driving teeth 46 are defined in the upstanding arms 48 of the driving member 18. The relative dimensions of the teeth 42 and 46 and of the arms 44 and 48 are as follows. The retaining teeth 42 in the U-shape retaining member 16 have the same depth and length as the driving teeth 46 in the U-shape driving member 18. The depth of the teeth 42 and 46, as seen best in FIGS. 2 and 3, is made equal to the diameter of the staples 22. And, as best seen in FIGS. 1, 8 and 9, the height of the arms 44 is substantially larger than the height of the arms 48, these relative heights being defined so that when the U-shape driving member 18 is mounted in the U-shape retaining member 16, the peaks of the retaining teeth 42 lie in the same plane as the peaks of the driving teeth 46. The reason for this alignment will become clear when the operation of the cartridge is described.

The rear of the U-shape driving member 18 takes the form of an extension bar 50 which terminates in a rectangular tooth 52. A rectangular slot, shown generally at 54, is defined in the rear of the pusher 20 and is dimensioned so as to comfortably house the rectangular tooth 52. The rear wall 56 of the slot 54 is beveled, as seen in FIGS. 1 and 4, for reasons which will be more fully explained below. The rearwardmost wall 58 of the pusher 20 is also beveled, as best seen in FIGS. 1 and 4. Again, the reason for this beveling will be explained below.

A second slot 60 is defined in the body of the pusher 20 and is sized so as to communicate with a drive bar 62 taking the form of the thrust member of the associated medical instrument. The medical instrument is of the type fully described in the first of the two above-noted U.S. patent applications, and, consequently, will not again be described in detail. Suffice it to say that when the instrument is triggered by the physician, the drive bar 62 moves in the direction of the arrow 64 (FIG. 4). Then, after the maximum drive stroke is reached, the drive bar returns to its fully retracted position.

To facilitate the insertion of the drive bar 62 in the slot 60, the upper casing 14 is provided with an elongated slot 66. The length of the slot 66 is made so as to allow the drive bar 62 complete freedom of movement in both its forward and rearward drive strokes. Upstanding tabs 68 are also fit on the upper casing member 14, and, as explained in the first of the two above-noted U.S. patent applications, tabs 68 serve to maintain the cartridge 10 in the body of the associated medical instrument while allowing freedom of movement of the bar 62.

From FIGS. 1, 8 and 9, one further feature of the upper casing 14 should be noted. This feature relates to the manner in which the staples 22 are guided by the guide ledge 30, the ramp 32 and the internal surface of the upper casing 14. In FIG. 1, it can be seen that the height of the casing, as it affects the staples 22, changes near its front. This can be seen by comparing FIGS. 8 and 9. In FIG. 9, a cross section taken near the middle of the cartridge 10, the staples 22 are held by the ledges 30 and the internal wall of the upper casing 14 at a height below the plane of the pusher 20. In FIG. 8, on the other hand, a cross section taken near the front of the cartridge 10, the staples are held by the ramps 32 and the internal wall of the upper casing 14 at a height which puts them in the plane of the pusher 20. The reason for this will become clear from the following.

As previously noted, the inventive staple-housing cartridge is made disposable. Accordingly, the components of the cartridge are sterilized, the cartridge is fully assembled and is then packaged and sealed in a presterilized envelope for transportation and sales. The construction of the cartridge, shown exploded in FIG. 1, is quite simple. The U-shape retaining member 16 is fitted within the hollow of the lower casing 12. Then, the U-shape driving member 18 is positioned within the track 39 of the retaining member 16. The driving member 18 is moved to its rearwardmost position and a plurality of staples, preferably equal in number to the number of teeth in the driving member 18, are positioned in the aligned teeth of the driving member 18 and the retaining member 16 (FIG. 4). Then, the pusher 20 is fit on the top of the driving member 18 with the rectangular tooth 52 extending into the slot 54. The upper casing 14 is snapped in place and the cartridge is ready to be packaged for shipment.

The operation of the disposable cartridge is as follows. With the cartridge 10 properly mounted in the associated medical instrument and the drive bar 62 extending through the slot 66 in the upper casing 14 and engaging the slot 60 in the pusher 20, the relative positions of the elements are as shown in FIG. 4. As can be seen from this Figure, the teeth of both the retaining member 16 and the driving member 18 are in substantial transverse alignment, the teeth of member 18 being retracted slightly more, in the rearward direction, than the teeth of member 16. This ensures that the teeth 46 in member 18 engage the staples 22. And, as also evident, the staple 22 nearest the forward end of the cartridge 10 is supported by the ramp 32.

When the instrument is fired, as shown in FIG. 5, the drive bar 62 moves in the direction of arrow 64. With the downwardly projecting portion of the drive bar 62 engaging the slot 60 in the pusher 20, the movement of the drive bar 62 brings about a corresponding movement in the pusher 20. And, because the rectangular tooth 52 integral with the driving member 18 is housed within the slot 54 in the pusher 20, movement of the pusher causes movement in the driving member.

With the driving member 18 moving in the direction of arrow 64, each tooth 48 drives its associated staple toward the front of the cartridge 10. As seen in FIGS. 2 and 8, the movement of the driving member 18 in the direction of arrow 64 causes the arms 44 of the retaining member 16 to flex out of the plane of the staples. The flexing of the retaining member 16 is shown, in phantom, in FIG. 8 and is indicated in FIG. 2 by the arrows 70.

As best seen in FIG. 4, with the driving member 18 in its rearwardmost position, the stroke, designated by S is defined by the distance between the front of the driving member 18, when in its rearwardmost position, and the forward wall 24 in the lower casing 12. As also seen in FIG. 4, the distance S is somewhat greater than the peak-to-peak dimension L of the teeth 42 and 46, as is common in all ratchet and pawl drive mechanisms, to ensure proper tooth engagement.

When the drive bar 62 drives the pusher 20 and, in turn, moves the driving member 18, there is unison of motion until the front wall of the driving member 18 abuts the wall 24 in the lower casing 12. At this instance, the relative positions of the elements are as shown in FIG. 5. It will be noted that the forwardmost jaw of the pusher 20 is behind the forwardmost staple 22 and that the forwardmost staple 22 is in the plane of the pusher ready for ejection.

With further movement of the drive bar 62 in the direction of arrow 64, the pusher 20 attempts to continue its movement of the driving member 18 in the direction of arrow 64. However, this is not possible. Further movement of the pusher 20 causes the extension 50, integral with the driving member 18, to slide along the inclined surface 56 and out of the slot 54 at the rear of the pusher 20. With the pusher 20 free from engagement with the driving member 18, the forward motion of the pusher continues until the forwardmost staple 22 is ejected from the body of the cartridge 10 and formed around the anvil 72 in a manner fully described in each of the above-referenced copending U.S. patent applications. The condition of the cartridge 10 at the completion of the staple advancing and ejecting operations is shown in FIGS. 6 and 7. It should be evident that for each forward stroke of the driving member 18, all staples are moved from their respective teeth in the retaining member 16 to the next successive teeth.

Once the drive bar 62 and the pusher 20 have reached the forwardmost portions of their strokes, they begin their return strokes. For the first portion of the return stroke, the pusher 20 moves while out of engagement with the driving member 18. However, when the rear wall 58 of the pusher 20 contacts the front wall of the rectangular tooth 52, the sloping wall 58 flexes the extension 50 in a downward direction and causes the tooth 52 to enter the slot 54. Then, the drive member 18 is retracted, by the pusher 20, into its preadvance position.

As shown in FIGS. 3 and 9, the movement of the pusher 20 in the direction of arrow 74, and the corresponding movement of the drive member 18, causes the arms 48 of the drive member 18 to flex out of the plane of the staples 22, as shown in phantom in FIG. 9 and as indicated by arrows 76 in FIG. 3. As is evident from FIG. 3, the flexing of the arms 48 is necessitated by the engagement of the staples 22 by the teeth 42 of the retaining member 16. The return stroke of the drive member 18 continues until the drive member again takes the position shown in FIG. 4. The cartridge is then ready for another firing operation.

The U-shape retaining member 16 and the U-shape driving member 18, because of the requirement that the respective arms 44 and 48 be capable of bending, is made of a material which yields under force. However, because of the requirement that the respective teeth 42 and 46 be capable of retaining or driving staples, the material of the retaining member 16 and the driving member 18 must be relatively incompressible. While many plastic materials meet these requirements, one suitable material is sold under the trade name "Lexan."

As is evident from the above, the staple-carrying cartridge of the present invention can house a number of staples limited only by the length of the cartridge. As should also be evident, the inventive cartridge can be fired by a powering unit having only rectilinear thrust capabilities. And, while the cartridge is extremely simple in design, having but two moving parts, its operation is both efficient and reliable.

Above, a specific embodiment of the present invention has been described. It should be appreciated, however, that this embodiment is described for purposes of illustration only and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is the intent that the invention not be limited by the above but be limited only as defined in the appended claims.

Claims

We claim:

1. A surgical stapling cartridge adapted to house a plurality of staples, to associate with a surgical instrument having only rectilinear thrust capabilities, and being particularly suited for stapling skin and fascia of a surgical patient, the cartridge comprising: an elongated retaining member fixed against movement in its longitudinal direction; an elongated driving member having a length less than the length of said retaining member, said driving member being slidably mounted with respect to said retaining member; a plurality of staple-retaining teeth resiliently associated with said retaining member; a plurality of staple-driving teeth resiliently associated with said driving member; the teeth in said retaining member and the teeth in said driving member being related, when relaxed, in such a manner that the peaks of said teeth lie in a single plane; means to drive said driving member, thereby advancing each of the staples in said cartridge toward the front thereof; and pusher means for expelling and bending a single staple for each forward thrust thereof.

2. The cartridge recited in claim 1, wherein said retaining member and said driving member are U-shape and wherein said teeth are positioned at the extremities of the arms of the respective U-shape members.

3. The cartridge recited in claim 1, and further comprising: ledge means defined in said cartridge and serving to support and guide said plurality of staples out of the plane of said pusher means; and ramp means at the forwardmost region of said ledge means, and serving to move the forwardmost staple into the plane of the pusher means.

4. The cartridge recited in claim 1, wherein the stroke of said pusher means is longer than the stroke of said driving member, and further comprising: means for releasing said driving member from said pusher means during the forward stroke of said pusher means; and means for ensuring the engagement of said pusher means with said driving member during the rearward stroke of said pusher.

5. The cartridge recited in claim 4, wherein said driving member is released from said pusher means only after the forwardmost staple is in the plane of said pusher.

6. The cartridge recited in claim 1, wherein said retaining member and said driving member are U-shape; wherein said driving member is slidably mounted within the arms of said retaining member; and wherein said retaining member and said driving member are flexible so as to allow the respective teeth to move out of said single plane.

7. The cartridge recited in claim 6, wherein said plurality of staples are driven by the teeth of said driving member; wherein the teeth of said retaining member move out of said single plane during the forward stroke of said driving member; wherein the teeth of said retaining member maintain the positions of said staples during the rearward stroke of said driving member; and wherein the teeth of said driving member move out of said single plane during the rearward stroke thereof.

8. The cartridge recited in claim 7, wherein the length of the stroke of said driving member is substantially equal to the distance between successive teeth.

9. The cartridge recited in claim 7, wherein the length of the stroke of said driving member is somewhat greater than the distance between successive teeth.

10. The cartridge recited in claim 7, wherein the dimensions of the teeth in said retaining member are substantially identical to the dimensions of the teeth in said driving member.

11. The cartridge recited in claim 1, wherein the depth of the teeth in said retaining member and in said driving member is substantially equal to the diameter of said staples.