Surgical stapling instrument

A surgical stapling instrument having a staple fastening assembly including a curved cartridge device. The device has at least one curved open row of staples having a first and second ends and having a concave side and a convex side. Opposite to the cartridge device there is a curved anvil for forming the ends of the staples. The instrument also includes a moving device adapted to move the anvil with respect to the cartridge device in a parallel relationship. The instrument also includes a staple driving device adapted to drive the staples out of the cartridge device towards the anvil, and a knife. The knife has opposing first and second sides and is contained in the cartridge device. There is also a knife actuating device adapted to move the knife towards the anvil. The instrument includes staple fastening assembly having a retaining pin which moves between the cartridge device to align them. The retaining pin is located on the second side of the knife in an intermediate region between the first end and second ends of the curved row of staples.

FIELD OF THE INVENTION

The invention relates to a surgical stapling instrument, which can be used, e.g., in the diagnosis and therapy of all pathologies treated by a curved stapled resection.

BACKGROUND OF THE INVENTION

Such a surgical stapling instrument is known from WO 01/91646 A1. WO 01/91646 A1 discloses a surgical stapling instrument having a staple fastening assembly located in the distal end region of the stapling instrument, a shaft, and a handle extending from the shaft in the proximal end region of the stapling instrument. The staple fastening assembly includes a curved cartridge device, which comprises several curved open rows of staples having a concave side and a convex side. A curved anvil is arranged opposite to the cartridge device. The anvil has a staple forming face and is adapted to cooperate with the cartridge device for forming the ends of the staples exiting from the cartridge device. The anvil can be moved relatively with respect to the cartridge device from a spaced position for positioning tissue therebetween to a closed position for clamping the tissue. Moreover, a knife is contained in the cartridge device and is positioned on the concave side of at least one row of staples.

The surgical stapling instrument disclosed in WO 01/91646 A1 can be used to excise tissue, e.g. polyps, and to stop bleeding virtually immediately. In a surgical procedure, the stapling instrument is introduced, e.g., into the anal canal and moved to the site of the tissue to be resected. The tissue to be excised can be pulled into the area between the anvil and the cartridge device, when the cartridge device and the anvil are in a spaced or open position, by means of a separate gripping instrument. Afterwards, the cartridge device is moved relatively with respect to the anvil in order to clamp the tissue. When the cartridge device and the anvil have reached the closed position, the surgeon can “fire” the instrument, which means that the staples are driven out of the cartridge device, penetrate the tissue, whereupon the ends are bent by the anvil, and the knife is moved towards the anvil in order to cut the tissue. When the instrument is retracted, the completely excised tissue stays in the staple fastening assembly and can thus be safely removed from the patient's body.

A particular advantage of the surgical stapling instrument disclosed in WO 01/91646 A1 is the shape of the staple fastening assembly in which the cartridge device and the anvil have a generally arc-like shape in a cross-sectional plane. This allows for unobstructed view and access towards the concave inner faces of the cartridge device and of the anvil.

In the surgical stapling instruments known from WO 01/91646 A1, the anvil is supported by means of an arm extending from an end of the anvil and generally running in parallel to the direction of relative movement of the anvil with respect to the cartridge device. The other end of the anvil is not supported. Thus, under load when the tissue to be resected is clamped, the anvil might distort, leading to a misalignment of the ends of the staples and the staple forming face of the anvil. For small surgical stapling instruments designed to be inserted through a small-diameter channel, this is a particular problem as there is not space enough for a sufficiently dimensioned, strong support arm at the end of the anvil.

In order to overcome this drawback, it has been proposed to use a retaining pin, which does not impede the free access to the space between the anvil and the cartridge device, but which is moved, after clamping the tissue, between the cartridge device and the anvil in order to align the cartridge device and the anvil. Such retaining pin is disclosed in PCT/EP03/06352. The retaining pin is located close to the free end of the anvil/cartridge device. In the cases when the length of the tissue to be excised is less than the arc length of the device, the known retaining pins do not cause risks of unwanted piercing of tissue.

It is possible, however, that tissue to be excised is longer than the arc length of the device. In those cases the stapling instrument must be applied more than once, substituting the spent staple cartridge with a loaded one. The problem of current stapling instruments with a retaining pin at the free end of the cartridge device is that their retaining pin leaves a hole in the tissue outside the excision line defined by the knife length.

It is the object of the invention to improve the clinical benefits of a surgical stapling instrument as generally known from WO 01/91646 A1, without jeopardizing its technical performance.

This problem is solved by a surgical stapling instrument having the features of claim1. Advantageous versions of the invention follow from the dependent claims.

The surgical stapling instrument according to the invention comprises a staple fastening assembly including a curved cartridge device and, opposite to the cartridge device, a curved anvil. The cartridge device comprises at least one curved open row of staples having a first end and a second end and having a concave side and a convex side. The anvil has a staple forming face and is adapted to cooperate with the cartridge device for forming the ends of the staples exiting from the cartridge device. Moreover, a moving device is adapted to move the anvil relatively with respect to the cartridge device, essentially in parallel relationship, from a spaced position for positioning tissue therebetween to a closed position for clamping the tissue. A staple driving device is adapted to drive the staples out of the cartridge device towards the anvil. In the cartridge device, there is contained a knife having a first side and a second side opposite to the first side. The knife is positioned on the concave side of at least one row of staples, the first side of the knife facing to said row of staples. A knife actuating device is adapted to move the knife towards the anvil. According to the invention, the staple fastening assembly comprises a retaining pin adapted to move between the cartridge device and the anvil to align the cartridge device and the anvil. The retaining pin is located on the second side of the knife in an intermediate region between the first end and the second end of the curved row of staples.

In other words, the retaining pin is not located at an end of the curved row of staples, but it is situated in an area where tissue which might be penetrated by the retaining pin upon movement of the retaining pin will be excised when the knife is actuated. Consequently, there is no risk that healthy tissue or tissue remaining in the patient's body will be injured by the retaining pin. The importance of the position of the retaining pin will be better understood by means of the description of an embodiment of the invention following further below.

Preferably, the stapling instrument according to the invention comprises a shaft device and a handle, the staple fastening assembly being located in the distal end region of the stapling instrument and the handle extending from the shaft device in the proximal end region of the stapling instrument. In a preferred version of the invention, the staple fastening assembly is removably mounted in the distal end region of the shaft device. In this way, the shaft device, which can include many components of the moving device, the staple driving device, the knife actuating device and members used to move the retaining pin, can be designed as a single-patient reloadable device, whereas the staple fastening assembly can be designed as a single-fire disposable article which is replaced after its staples have been delivered. Preferably, the movement of the retaining pin is actuatable via an actuating member located at the handle. In a preferred embodiment, the direction of movement of the retaining pin is essentially in parallel to the direction of relative movement of the anvil with respect to the cartridge device.

The staple forming face of the anvil can be generally planar, but other shapes, e.g. an undulated shape, are conceivable as well.

In an advantageous version of the invention, the staple fastening assembly is adapted to allow unobstructed access towards concave inner faces of the cartridge device and of the anvil. Such design, which is generally known from WO 01/91646 A1, largely facilitates the handling of the stapling instrument in a surgical procedure.

Preferably, the cartridge device and the anvil have a generally arc-like shape in a cross-sectional plane, the arc extending over an angle in the range 10° to 350°.

In a preferred version of the invention, the anvil is supported by means of an arm extending from an end of the anvil and generally running in parallel to the direction of relative movement of the anvil with respect to the cartridge device. This kind of support allows for a large unobstructed area between the cartridge device and the anvil but has the general disadvantage that it is less rigid than, e.g., a design using a support arm in the center of the cartridge device and the anvil or using more than one support arm. However, this disadvantage is compensated by the presence of the retaining pin by means of which the cartridge device and the anvil are aligned during the steps of the procedure when an alignment is critical, i.e. in particular when the cartridge device and the anvil are moved toward one another to force the tissue to compress to a thickness such to be stapled across and when the staples are then “fired” from the cartridge device and are formed by grooves in the staple forming face of the anvil.

Preferably, the distance between the cartridge device and the anvil in the closed position is adjustable. For example, the moving device can comprise an adjustable stop in order to prevent the cartridge device (or anvil) from moving beyond the stop position and from clamping the tissue too much. Or a series of cartridge devices with different built-in tissue stops can be used according to the tissue thickness. It is also conceivable to use a series of cartridge devices which have different longitudinal dimensions which are adapted to the desired distance between the cartridge device and the anvil in the closed position. By adjusting the distance between the cartridge device and the anvil in the closed position, the instrument can be matched to the thickness and type of tissue to be stapled and excised.

In an advantageous version of the surgical stapling instrument, the cartridge device comprises a replaceable cartridge containing staples. In this way, a used cartridge without staples can be replaced with a fresh one, if required. This is particularly beneficial when the instrument is to be used several times during the same surgical procedure.

Some of the features discussed above are already known from WO 01/91646 A1, in particular an arc-like shape of the cartridge device and the anvil and a support arm extending from an end of the anvil, which enables an easy access to the site of surgery, e.g., for endoscopic optics or additional surgical instruments. The retaining pin of the present invention allows for a greater precision of the surgery without involving the risk of injury to tissue that may not be removed from the patient in the form of a specimen.

Herein, the term “staple” is used in a very general sense. It includes metal staples or clips, but also surgical fasteners made of synthetic material and similar fasteners. Synthetic fasteners usually have a counterpart (retainer member) held at the anvil. In this sense, the terms “anvil” and “staple forming face” also have a broad meaning which includes, in the case of two-part synthetic fasteners, the anvil-like tool and its face where the retainer members are held, and similar devices.

Generally, the stapling instrument according to the invention can be used in all kinds of surgery disclosed in WO 01/91646 A1, which is incorporated by reference herein.

DETAILED DESCRIPTION

The surgical stapling instrument of the embodiment, which is designated by the reference numeral1, has a similar design as the surgical stapling instrument described in detail in WO 01/91646A1. In addition to that instrument, however, the stapling instrument1includes a retaining pin in order to align the cartridge device and the anvil, as explained below.

The stapling instrument1comprises a staple fastening assembly2which is mounted at the distal end of a shaft4.FIGS. 1 to 4show the distal portion of shaft4only. In its proximal region, shaft4is attached to a handle having actuating members for operating the functions of the stapling instrument1, as is known in the art. Force transmitting elements for transmitting the movements of the actuating members to the movable parts of the staple fastening assembly2are guided inside shaft4or in channels located at the surface of shaft4. In the present embodiment, the staple fastening assembly2is fixed at the distal end of shaft4. A design in which the staple fastening assembly is removably mounted is conceivable as well.

The staple fastening assembly2comprises, in its proximal area, a staple housing portion6and opposite to that, in its distal area, an anvil8. The staple housing portion6has a fixed guide portion10which guides a movable cartridge device12. At one of its ends, the anvil8is supported by means of an arm14which extends from the guide portion10in longitudinal direction, i.e. essentially in parallel to the longitudinal axis of shaft4.

The cartridge device12includes a cartridge containing at least one, but preferably (in the embodiment) four open rows of staples and a knife for cutting tissue. The geometry and the relative arrangement thereof will be explained in more detail by means ofFIG. 5below. Because of that geometry, the cartridge device12and the anvil8have a curved, arc-like shape, as seen inFIGS. 1 to 4. In the embodiment, the arc extends over an angle of somewhat less than 90°. The geometry of the staple fastening assembly2allows for an unobstructed access towards the concave inner faces of the cartridge device12and the anvil8, i.e. towards the curved face of the staple fastening assembly (2) visible inFIGS. 1 to 4.

The anvil8has a staple forming face16with staple forming depressions18for forming the ends of the staples exiting from cartridge device12when the surgical stapling instrument1is “fired”, seeFIG. 1. The staple forming depressions18are arranged in four arc-like rows in order to match the geometry of the rows of staples.

In the middle area of the concave inner faces of the guide portion10and the movable cartridge device12, in parallel to shaft4, a retaining pin20(seeFIGS. 3 and 4) is slidably guided in a guide member22mounted at the staple housing portion6, an actuating rod for retaining pin20being slidably housed in a guide channel24mounted alongside shaft4. The retaining pin20can be moved in distal direction by means of an actuating member located at the handle of the stapling instrument1(not shown in the Figures). The distal end26of the retaining pin20has a pointed or tapered shape, seeFIG. 4. When the retaining pin20is moved in distal direction, its end26fits into a counter-part28mounted at the concave inner face of anvil8. Counter-part28has a longitudinal bore which can be easily hit by the pointed or tapered end26, even if the anvil8is somewhat misaligned with respect to the cartridge device12, due to the limited rigidity of the design. When the retaining pin20protrudes further in distal direction, its end correctly aligns the bore in counter-part28, thus aligning the locations of the staples in the cartridge device12with the staple forming depressions18.

FIGS. 1 to 3show three steps in the operation of the surgical stapling instrument1.

InFIG. 1, the cartridge device12is in a spaced position with respect to the anvil8. In this state, tissue to be excised by means of the stapling instrument1can be positioned between the cartridge device12and the anvil8(see alsoFIG. 5).

In the next step, the cartridge device12is moved towards the anvil8in order to slightly clamp the tissue between the cartridge device12and the anvil8, seeFIG. 2. In an advantageous version of the embodiment, the final distance between the cartridge device12and the anvil8can be adjusted in order to avoid excessive pressure exerted on the tissue. The details of the moving device adapted to move the anvil8relatively with respect to the cartridge device12are known to the person skilled in the art, see also WO 01/91646 A1.

In the state shown inFIG. 2, the anvil8might be slightly misaligned with respect to the cartridge device12, which could cause problems when the staples are formed. Therefore, in the next step shown inFIG. 3(orFIG. 4), the retaining pin20is moved in distal direction until its end26has aligned anvil8by means of the counter-part28. In this state, the stapling instrument1can be finally closed and “fired”, i.e. the tissue compression travel is completed forcing the tissue to the wanted thickness and the actuating member for expelling the staples out of cartridge device12is operated.

As already mentioned above, the geometry of the staple arrangement, the knife and the retaining pin20is illustrated by means ofFIG. 5, which essentially is a schematic view onto the end face30of the cartridge device12.

The cartridge device12is provided with a plurality of slots32which are arranged in concentric arcs. Each slot32houses one staple, with its pointed ends facing towards the end face30. In the embodiment, there are four rows of staples, i.e. rows34to37. The slots of adjacent rows of staples (rows34,35and rows36,37) are staggered with respect to each other. Between rows35and36,FIG. 5shows an arc-like knife guide38, i.e. a slot housing an arc-like knife.

Row34, e.g., has a first end40, a second end41, a concave (inner) side42and a convex (outer) side43. The first side44of the knife (i.e. its convex side) faces row34, whereas its second side45(opposite to the first side44) faces the retaining pin20. Thus, the retaining pin20is located on the second side45of the knife housed by the knife guide38in an intermediate region between the first end40and the second end41of the curved row of staples contemplated, i.e. row34.

FIG. 5illustrates a state when tissue50of a patient has been drawn into the space between the cartridge device12and the anvil8by means of some auxiliary instrument. After this tissue has been clamped between the cartridge device12and the anvil8, the retaining pin20is protruded, as described before. In this way, it penetrates the tissue50. This does not cause any harm to the patient, however, since immediately afterwards, the stapling instrument1is “fired”. This means, the staples are expelled, and the staggered rows34and35of staples form a reliable suture which almost immediately stops bleeding. The staples of rows36and37form a similar suture in the cross-hatched portion of the tissue50, thus strengthening the tissue to be excised, stopping bleeding of this excised tissue portion as well. Immediately afterwards, the knife is driven out of the knife guide38, thus excising the cross-hatched part of the tissue50.

Consequently, the tissue hurt by retaining pin20does not stay inside the patient.

FIG. 5also illustrates a case when the tissue to be excised extends over an area which is larger than the arc length of the knife. The periphery of the additional tissue is indicated by a dashed line and reference numeral52. When the stapling instrument1is used in order to excise the total tissue area50,52, it has to be applied several times, e.g. two times in the example, wherein a spent staple cartridge is replaced by a loaded one before the respective next application. Nevertheless, the position of retaining pin20ensures that the tissue pierced by the retaining pin20during a given application is excised during the same application.

In a prior art instrument, the retaining pin is located at the end of the device, e.g., inFIG. 5at the position marked with an asterisk54. In the situation when the stapling instrument is used several times, there is an appreciable risk that the tissue pierced by retaining pin54in a given application is not excised in the next application, thus leaving hurt tissue in the patient.