Elongated-member-driving apparatus – Surgical stapler – With magazine
Reexamination Certificate
2000-01-24
2001-02-27
Smith, Scott A. (Department: 3721)
Elongated-member-driving apparatus
Surgical stapler
With magazine
C227S019000
Reexamination Certificate
active
06193129
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates, in general, to surgical stapling instruments for applying surgical staples to tissue and, more particularly, to a circular surgical stapling instrument having an improved circular blade.
BACKGROUND OF THE INVENTION
Circular surgical staplers are well known in the surgical field for the ease with which the instrument performs a previously difficult anastomotic stapling operation—the hemostatic joining of two pieces of tubular tissue together with a ring of staples. Such an instrument is ideally suited for intestinal or bowel surgery, and an instrument of this type is the Endopath™ ILS Endoscopic Curved Intraluminal Stapler manufactured by Ethicon Endo-Surgery, Cincinnati, Ohio. The circular stapling instrument has a distal stapling head that is available in a variety of sizes to match the organ size of the patient.
Circular stapling instruments are best known for their ability to anastomose or attach two pieces of intestinal or bowel tissue together in an end-to-end fashion. In general, staples are known to provide a good degree of hemostasis when applied to tubular tissue such as intestine or bowel. Circular stapling instruments hold a plurality of staples in an annular array of concentric rings within a body of the distal stapling head. A moveable anvil is used to compress or clamp the pieces of intestinal tissue together between the body and the anvil of the stapling head. A firing trigger is operatively coupled to the stapling head and actuation of the trigger ejects the annular array of staples from the body of the stapling head. The ejected staples pierce the clamped tissue and are formed into a ring of “B” shaped staples that securely join the pieces of intestinal tissue together. A circular blade or scalpel of generally cylindrical shape is located within the stapling head and is advanced distally to sever a small ring or “donut” of excess tissue from between the annular array of formed staples. Severing the donut of tissue opens a passageway between the joined pieces of intestinal tissue. The anastomosed tissue is released from the circular instrument by distally advancing the anvil away from the staple holder and drawing the anvil out through the passageway within the annular array of formed staples. Such a device was disclosed by Becht in U.S. Pat. No. 4,207,898 and by Rothfuss in U.S. Pat. No. 4,319,576.
One improvement to the circular stapler that has been well received by surgeons is the inclusion of a breakaway or backup washer within the anvil of the surgical stapler. The breakaway washer is an annular member of semi-rigid material located within the anvil in a location directly opposite to the circular blade. The annular ring has a pair of spaced annular walls joined together at the proximal end by a thin web of material. The thin web of material faces the circular blade and supports tissue as the circular blade is advanced. The advancing circular blade severs the clamped tissue and is slowed by contact with the thin web of the breakaway washer. A cutting edge of the circular blade is substantially parallel to the thin web of the breakaway washer such that the entire cutting edge contacts the thin web of the breakaway washer in a circular ring of contact. Continued application of force partially severs the thin web of material and the remaining thin web material abruptly breaks due to the applied pressure. As the breakaway washer breaks, the load or force required to advance the circular blade drops abruptly. This abrupt force change provides the surgeon with a clear tactile and an audible indication that the instrument has been fired. A circular stapling instrument having a breakaway or backup washer is taught in U.S. Pat. No. 4,289,133, by Rothfuss.
It is important to note that U.S. Pat. No. 4,289,133 discloses a circular blade having an annular cutting edge that is generally parallel to the thin web of the breakaway washer. The parallelism of the cutting edge to the thin web maximizes the contact area of the blade with the thin web and maximizes the input force required to sever the breakaway washer.
Whereas the breakaway washer was indeed a breakthrough device providing the surgeon with an audible and tactile indication that the anastomosis of the tubular organs is complete, the force required to sever or break the breakaway washer amounted to a large portion of the firing force of the instrument. The force required to break the breakaway washer rises to an abrupt peak over a narrow portion of the firing trigger stroke. An alternate embodiment of the circular blade disclosed in U.S. Pat. No. 4,289,133 is a circular blade having an undulating cutting edge. The undulating cutting edges has both peaks and valleys, and the peaks of the cutting edge contact and slices the breakaway washer before the valleys. The undulating cutting edge does not cut the entire thin web simultaneously and this distributes the cutting of the breakaway washer over a larger part of the firing stroke. This reduces the peak cutting forces, and the blade slices rather than penetrates or punches through the thin web.
Whereas the undulating cutting edge does indeed reduce the load or force to break the washer, it is accomplished by spreading the load over a larger portion of the firing stroke. Testing has indicated that an undulating cutting blade gradually slices the breakaway washer and does not provide the tactile and audible feeling that that is preferred by many surgeons.
Thus, an invention that reduces the peak firing force and provides a tactile and audible signal to the surgeon would be more acceptable. Presently, there is no known surgical anastomosis stapling instrument that can provide an improved interaction between the circular blade and the breakaway washer such that the surgeon is provided with both the desired tactile and audible feedback, and a reduction of the force needed to fire the instrument.
SUMMARY OF THE INVENTION
The present invention is a surgical cutting and stapling instrument for applying a plurality of staples to tissue. The surgical stapling instrument includes a handle portion and a firing trigger pivotably connected to the handle portion. A shaft extends from the handle portion and a stapling head is attached to the shaft. The stapling head has a distal face and an array of staple slots and staples located therein. The staples are operably coupled to the firing trigger. An anvil is coupled to the stapling head. The anvil has an array of staple forming pockets therein. The staple forming pockets are facing the distal face of the stapling head and are in alignment with the staple slots in the distal face for forming an array of the staples therebetween;
A breakaway washer is mounted within the anvil of the stapling head. The breakaway washer has a pair of parallel spaced walls and a thin web extending therebetween. The thin web faces the distal face of the stapling head.
A blade is located within the distal face of the stapling head and is operably coupled to the firing trigger. The blade has a distal cutting edge and at least one wedge spike protruding distally therefrom. The at least one wedge spike has a first and a second edge. The distal cutting edge and the at least one wedge spike face the annular thin web of the breakaway washer.
When the anvil is moved adjacent to the stapling head and the firing trigger is closed, the staples are formed and the blade is moved to sever breakaway washer. When the blade is moved, the at least one wedge spike of the blade penetrates the thin web of the breakaway washer and weakens the thin web by propagating at least one crack therein. The distal cutting edge of the blade severs the thin web having at least one crack therein.
That is, in a surgical procedure, the surgeon first clamps the surgical stapling and cutting instrument on tissue. Next, the surgeon fires the instrument is fired to form the staples in tissue. As the staples are formed, the wedge spikes of the blade penetrates the clamped tissue and the thin web of the breakaway washer. Lastly, the distal cu
Bittner John Raymond
Boling Dale Gene
Voegele Aaron Christopher
Capezzuto Louis J.
Ethicon Endo-Surgery Inc.
Smith Scott A.
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