Method for using a surgical rongeur

An improved rongeur for cutting bone or cartilage comprising two shaft members capable of reciprocating motion relative to each other wherein one shaft member terminates in a foot plate and the other shaft member comprises a combined cutting element and storage member is disclosed. The combined cutting element and storage member has a cutting edge at its distal end and a storage chamber proximate the cutting edge for collecting and storing cut pieces of bone or cartilage in an amount greater than the maximum bone or cartilage capable of being cut in a single full cut. The combined cutting element and storage member is truly disposable, rather than merely replaceable and requires the use of no tools or special assembly. The rongeur may be manually activated or activated by a solenoid and powered by a battery.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to surgical instruments, used to bite out or cut portions of bone or cartilage, and specifically to those of the Kerrison type, or similar type.

2. Description of the Related Art

Rongeurs are surgical instruments for the cutting away of human tissue, and most commonly, cartilage and/or bone. Kerrison rongeurs are utilized in spinal surgery to remove bone and to thereby gain access to the spinal canal. These rongeurs typically have a closable jaw, one member of which having a cutting end and the other member being a foot plate which must be placed beneath the tissue, generally bone or cartilage, to be cut.

For example, when a Kerrison rongeur is in use, the surgeon places the bone to be cut, such as the leading edge of the lamina of a vertebrae, within the open portion of the distal end of the rongeur. The surgeon then squeezes the handle of the rongeur which causes the moveable jaw member of the rongeur to be advanced through that portion of bone to reach the foot plate, and thereby amputating that portion of bone. Once the jaw members become full, the rongeur must then be completely removed from the surgical site and passed to the scrub nurse for the removal from the instrument of that cut portion of bone.

To facilitate the necessary function of the rongeur, the foot plate is generally cupped, as is the cutting end of the moveable jaw member. If only the moveable jaw member were cupped and the foot plate flat, then upon cutting with such an instrument the bone would be so compacted into that singular cup as to make it nearly impossible to remove the portion of bone cut. However, because the foot plate of the Kerrison rongeur is below the lamina and proximate to the dural sac, spinal cord, and nerve roots, there is a compelling need to avoid any excessive thickness of the foot plate itself. Therefore, the foot plate cup is generally not quite as deep as the cup in the moveable jaw member and thus, even in the double cup design, the cut portion of bone tends to be compacted proximally, making its removal nevertheless difficult. The removal from the instrument of the cut portion of bone often requires that the scrub nurse use a small rigid hook, or toothed forceps, and often further requires that the physician temporarily relinquish the instrument entirely to make such bone removal possible. Once cleaned, the instrument is returned to the surgeon who, in returning it to the surgical site, must then reorient himself to the task at hand. This sequence must then be repeated over and over again with each cut of bone. Typically, such spinal procedures unfortunately require many such cuts.

Essentially flat foot plates had been in use earlier this century, but proved to be undesirable because the opening of the jaw members to be able to get around the thickened portions of the vertebrae tended to exceed the capacity of the cup in the moveable jaw member and the bone cut would be markedly compressed during the cutting process. When the foot plate is flat, the mass of bone bitten is forcefully compacted into the singularly cupped recess of the movable jaw member such that it is extremely difficult to remove that bone after each cut.

A consideration of the structure and function of the prior art rongeurs, and specifically in regard to the foot plate structure and its requisite thickness, is quite revealing. It would appear that in use the foot plate is subjected to five types of forces.

Consistent with its intended purpose, the foot plate is subjected to, and must withstand, that force necessary to actually cut through the bone, which shall be referred to as the Bone Cutting Force. However, the surgeon has no way of knowing what that force is, or even when he has reached or exceeded it. Accordingly, the foot plate is invariably exposed to a second force significantly greater than the Bone Cutting Force which shall be called the Terminal Squeezing Force. The Terminal Squeezing Force occurs after the bone fragment has been cut and is caused by the surgeon generating force in excess of the Bone Cutting Force. This results in the relatively massive slide portion of the instrument being driven with great mechanical advantage against the foot plate. This occurs because the manufacturer of such a rongeur must allow for wear of the cutting surfaces and still allow for the jaw to still be able to close such that the slide portion of the instrument has a greater excursion than would be otherwise required to merely close the jaw members of the rongeur when the cutting surfaces are new.

A third force encountered by the foot plate is a product of the fact that the instrument jaw generally opens to an extent greater than the combined depths of the cups such that the solid bony contents are physically crushed. This is the Bone Crushing Force, and again is additional to the Bone Cutting Force.

A fourth force that may impact upon the foot plate is that which occurs when the jaws of the rongeur encounter an object, which because of its physical structure, is unbiteable. In this situation, while the jaw is still in a relatively open position, again a force greater than the Bone Cutting Force is generated and in this case is then transmitted through the unbiteable object to the foot plate.

The fifth force to which the foot plate is subjected is leverage. When the jaws are not sufficiently sharp, or are worn such that they fall to completely close, then the bone will not be completely cut through, and the surgeon will rock the instrument back and forth to fracture through the remaining bony bridge. In this situation, the angle of the jaw in contact with the leading edge of the lamina becomes the fulcrum point and the foot plate, measuring generally less than half of an inch in length, is one lever arm, while the remainder of the instrument through the shaft and handle is the other. Since these instruments generally measure on the order of approximately 10 inches, the mechanical advantage, or force applied to the tip in a rocking maneuver is on the order of magnitude of 20 to 1.

The ability to safely withstand repeated exposure to these five forces, and the previously discussed need to cup the inner surface of the foot plate, have in the past, determined the requisite thickness of the foot plate.

At present, there is also a need for a rongeur with a capacity to remain within the wound and to repeatedly bite bone and to store the bone bitten until all the requisite bone removal has been completed without the need to continuously remove the rongeur from the wound for the purpose of removing the cut portion of bone from the instrument to clear the cutting edges. A further and related need exists for a rongeur that would collect and contain all of the bitten material such that the delicate neural structures would be protected from contact with the bitten material and/or any cogenerated inadvertent debris. In this regard, any rongeur can bite more than once, but not properly. That is, one could deliberately take several small bites, each of which would fail to fill the cup in the foot plate and the singularly cupped recess of the moveable jaw member, in lieu of taking one full bite. However, once the cup in the foot plate and the cupped recess of the moveable jaw member are filled, further biting is not possible. Bone may be crushed as cups that are already full approach one another, but their contents will shield any further interposed bone from the cutting edges, thus making any further bone cutting impossible.

An example of a multibite rongeur is shown in U.S. Pat. No. 3,902,498 issued to Niederer on Sep. 2, 1975. Niederer teaches the use of a rongeur hollow at the tip such that it is possible to take several bites. Unfortunately, since the hollow tip is open to the wound at both ends, the further use of the instrument pushes the already bitten material out of the other end of the hollow tip and back into the depths of the surgical wound where it can cause great harm. This shortcoming of Niederer can not be overcome by simply closing off the second opening as the operation of the instrument requires the second cutting member (8) to pass through the same area that the ejected bone had occupied.

Further, if a rongeur could take and then store safely, multiple full bites of bone, a rationale would then exist for a power rongeur. A prior art power rongeur was marketed by the 3M Company. However, it was very bulky and required a large bore hose connection to a non-sterile compressed gas tank making the instrument very unwieldy. The biting mechanism itself was rather slow and clumsy and the instrument still required removal from the wound after every bite to clean out the bitten portions of bone.

There is also a need for a disposable cutting means so that those portions of the rongeur involved in the actual cutting may be easily renewed as these portions of the rongeur rapidly wear and dull from the cutting of bone. With wear comes both edge dullness and non-mating of the contact surfaces rendering the rongeur ineffective and even dangerous as it fails to cut cleanly and begins to rely on tearing.

Both U.S. Pat. No. 3,902,498 issued to Niederer and U.S. Pat. No. 5,026,375 issued to Linovitz et al. disclose a means for replacing the cutting element on just one side of the jaw in a rongeur appearing to have cutting cupped portions on both sides of the jaw. Since dulling and wear occurs equally on both sides of the jaw, replacing only one side is obviously ineffective in restoring the sharpness and the full cutting function of the instrument or for even providing for the proper mating of the cutting surfaces as one new side is then opposed to one worn side.

Reference is made to U.S. Pat. No. 4,722,338 to Wright et al. and U.S. Pat. No. 4,777,940 to Wright et al. U.S. Pat. No. 4,777,948 discloses a rongeur having a stationary hollow tubular cutting element28which may be removably attached to the rongeur. The entire assembly must be disengaged to replace the cutting element. The device is not capable of taking multiple full bites since only a short recess is provided for pulling the severed bone into the hollow cutting tube and contrary to that concept teaches that the bone is then ejected after each cutting operation, as explained in U.S. Pat. No. 4,722,338 at Col. 3, line 10. No collection of the cut bone is achieved by the hollow cutting element beyond a single cut and the cut bone is then ejected. In fact, the cut bone may be ejected into the wound, which could cause great harm.

Finally, there is a need for a Kerrison type rongeur that is capable of taking larger bites of bone than is now possible. While the need for such a rongeur exists, by prior art technology the foot plate would be too thick to safely use beneath the lamina, and the surgeon would lack the strength to crush and compact that volume of bone.

There is therefore a need for a Kerrison type rongeur with a thin, but strong, foot plate that would be able to take and safely store throughout the operation multiple full bites of bone. Such a rongeur would also have at least a disposable cutting element system capable of replacing all cutting edges to provide for the surfaces of the cutting edges to be sharp and close perfectly and would be capable of taking larger bites of bone than previously possible. Such a rongeur could be powered without the need for external connections to a remote power source.

SUMMARY OF THE INVENTION

The present invention is a rongeur for cutting bone or cartilage comprising two shaft members capable of reciprocating motion relative to each other wherein one shaft member terminates in a foot plate and the other shaft member comprises a combined cutting element and storage member. The combined cutting element and storage member has a cutting edge at its distal end and a storage chamber proximate the cutting edge for collecting and storing cut pieces of bone or cartilage in an amount greater than the maximum bone or cartilage capable of being cut in a single full cut. In one embodiment of the present invention the surgical rongeur is an ultra-thin foot plate, multi-bite (capable of taking multiple full bites) rongeur with a combined cutting element and storage member that is replaceable and disposable. The combined cutting element and storage member comprises a removable and disposable straw member having a sharp cutting end and an end that removably attaches to an engagement means for engaging the straw member to a carriage member such that the end is closed while in use. The combined cutting element and storage member is removably locked to at least one of the two shaft members.

The reciprocating motion of the two shaft members causes the combined cutting element and storage member and a foot plate to close and open in response to the activation of a driving member which may be hand operated or powered by a solenoid. The foot plate of the rongeur of the present invention is ultra-thin, such that it is substantially thinner than the foot plates of the rongeurs of the prior art. The ultra-thin foot plate of the present invention is made possible by the relative absence of any recess sufficient to hold bone after a cut is made and is substantially flat. The foot plate of the present invention need not be as thick as that of a conventional rongeur since the only force normally applied to it is that sufficient to actually cut the bone being bitten.

In one embodiment of the present invention, the foot plate-shaft junction area of the rongeur is designed to prevent the upward excursion of the combined cutting element and storage member along the foot plate. The terminal squeezing force is eliminated by providing a proximal stop to the movement of the slide portion of the instrument allowing only for the full opposition of the foot plate and combined cutting element and storage member but allowing no further motion. This absence of further motion in opposition to the foot plate thus serves to consequently protect it.

The bone compaction force that occurs with prior art rongeurs results from the fact that the rongeur must—to serve its purpose—open to an extent sufficient to accept the thickness of the bone being cut, which commonly exceeds the capacity of the two cupped surfaces. However, the present invention has no fully cupped surfaces and in fact the combined cutting element and storage member is functionally bottomless until full.

The force associated with levering is eliminated by eliminating the need for it which generally arises from a need to complete the cutting out of a piece of bone by fracturing through the remaining portion when such cutting is incomplete because of dulling of the cutting elements or a failure of them to fully and uniformally coapt. In the instance of the present invention as the cutting element is not only replaceable, but disposable, and as there is but a single cutting element which is replaceable for each new procedure the surgeon is assured that all of the cutting surfaces are optimally sharp and unworn such that those biting surfaces coapt perfectly. Prior art rongeurs that replaced but one of two equally important cutting edges failed to either restore full sharpness or to provide for perfect coaptation of those cutting surfaces.

During use, the combined cutting element and storage member is closed at its proximal end and open at its distal end terminating in an ultra-sharp cutting surface. Inasmuch as the combined cutting element and storage member is hollow, rather than cupped, and the opposed surface of the foot plate is substantially flat, the bone bitten is always driven rearward into the storage member portion. As the storage chamber is closed while in use except for the cutting entrance, it may be used to repeatedly bite bone without the danger of the bone bitten coming free and falling into the spinal canal in contradistinction to prior art rongeurs which required the ejection of bone before a second full bite could be taken.

When the present invention has completed its task and has removed all of the bone as needed, the combined cutting element and storage member may be removed from the shaft of the rongeur and the bitten bone may be removed from the storage member and made available for use, as in performing a spinal fusion.

The present invention allows for the clean cutting of bone or cartilage without any significant compaction. Further, as the combined cutting element and storage member of the present invention is disposable and thus always fresh and sharp, less force is required during the actual cutting of the bone. In addition, since the combined cutting element and storage member is always fresh and sharp, edge wear is not a problem and the capacity for further excursion of the combined cutting element and storage member towards the foot plate is unnecessary and may be completely blocked, thereby sparing damage to the foot plate.

Further, the present invention has a combined cutting element and storage member that is truly disposable, rather than merely replaceable and requires no special assembly or the use of any tools. The combined cutting element and storage member is simply placed onto one of the shaft members whereby it is immediately locked into place by the use of the instrument itself.

Finally, as the rongeur of the present invention is capable of taking repeated and uninterrupted multiple full bites of bone or cartilage, there is a compelling rationale for the incorporation of a power means to drive the rongeur and a self-contained power source to further allow the use of the rongeur to be unfettered.

OBJECTS OF THE PRESENT INVENTION

It is an object of the present invention to provide an improved surgical rongeur capable of taking multiple full bites of bone or cartilage without having to be removed from the wound after each bite.

It is another object of the present invention to provide an improved surgical rongeur capable of storing multiple cut pieces of bone or cartilage while the rongeur is in the wound.

It is yet another object of the present invention to provide an improved surgical rongeur having a combined cutting element and storage member.

It is a further object of the present invention to provide an improved surgical rongeur having a combined cutting element and storage member that is easily replaceable and disposable.

It is yet a further object of the present invention to provide an improved surgical rongeur having a replaceable and disposable combined cutting element and storage member that does not require the use of tools or special assembly.

It is still a further object of the present invention to provide an improved surgical rongeur having a combined cutting element and storage member which is simply placed onto the shaft of the rongeur, whereby it is immediately locked into place by the use of the rongeur.

It is another object of the present invention to provide an improved surgical rongeur with an ultra-thin foot plate.

It is a further object of the present invention to provide an improved surgical rongeur having an improved button assembly for controlling the displacement of a driving means along the shaft of the rongeur and for controlling the engagement or release of a combined cutting element and storage member, that also functions as a hinge for attaching the handle to the body of the rongeur.

It is another object of the present invention to provide an improved surgical rongeur having an improved means for the rapid engagement and disengagement of a disposable combined cutting element and storage member.

It is yet another object of the present invention to provide a surgical rongeur capable of taking multiple full bites which is activated by a solenoid.

It is still another object of the present invention to provide an electrical rongeur having a battery as a self-contained power source.

It is another object of the present invention to provide a surgical rongeur having a removable shaft portion which can be made in a variety of sizes and configurations and be interchangeably coupled to a manual or power handle means, wherein at least a portion of the removable shaft portion may be disposable.

It is still another object of the present invention to provide a surgical rongeur having a combined cutting element and storage member in communication with a vacuum means for evacuating any contents of the combined cutting element and storage member.

These and other objectives of the present invention shall be more clear upon review of the following detailed description of the drawings when reviewed in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring toFIGS. 1-4, the improved surgical bone rongeur10is shown constructed in accordance with the present invention and comprises generally of a body12having a rear handle13depending at an angle from the proximal end11of the body12, and has a shaft14extending distally and terminating at its distal end in a foot plate16. A support spike31extends from the upper portion of the rear handle13as support for the area of the hand between the thumb and the first finger. Mounted on the shaft14is a slide drive member20for reciprocating movement on the shaft14.

Referring toFIG. 2, a pivoting forward handle30includes a lower finger grip portion34and an upper finger portion37for the fingers. The upper part of the forward handle30has an extension33with an elongated opening35and an aperture36through which passes a pivot pin32. Extension33fits into the body12through slot19(shown inFIG. 5) and is contained within the body12.

Once the extension33is positioned within slot19, the pivot pin32, having a screw head39on one end and threads at its other end, is used to pivotally attach the forward handle30to the body12. The pivot pin32passes through opening15in one side of the body12through aperture36in the forward handle30and threads into threaded aperture17in the other side of the body12. The elongated opening35of the extension33surrounds pin42located at the bottom surface of slide drive member20which is mounted on the shaft14so that the forward handle30engages the pin42and serves as the driving means for the slide drive member20. The forward handle30is attached to the body12at an angle to the slide drive member20so that when the forward handle30moves proximally the slide drive member20moves distally. The forward handle30and the rear handle13are biased away from each other by spring means40and40a. Spring means40is attached at one end to the bottom of forward handle30by screw41and spring means40ahas one end attached to the bottom of rear handle13by screw43and may be further secured by having a bend in the end of spring means40acapable of fitting into an opening of rear handle13to prevent rotation of the spring means40arelative to rear handle13.

Referring toFIG. 7, in order to interlock the two spring means40and40a, spring means40has an extension piece45at its upper end that fits into the notch46of the upper end of spring means40a. Once interlocked, the spring means40and40aoppose each other to bias the forward handle30distally. Other spring mechanisms, internal or external, and other biasing means, including pneumatic means, may also be employed for urging the forward handle30distally.

Referring toFIGS. 4 and 5, the slide drive member20is slidably mounted to the top surface of shaft14within a slot24formed in the shaft14having an inverted T-shaped portion25into which is fitted a complementary inverted T-shaped runner26depending from the bottom surface of slide drive member20. Slot24extends distally from the inverted T-shaped portion25to form a wider portion27of the slot24.

Referring toFIG. 4, a stop pin60depends from the distal end61of the bottom surface of the slide drive member20. The stop pin60serves to guide the slide drive member20and to keep the distal end61of the slide drive member20from sliding off the shaft14during the operation of the rongeur10. The stop pin60is set back from the distal end61of the slide drive member20and fits within the wider portion27of slot24. The wider portion27of the slot24has a slot wall28at its distal end which catches the stop pin60and prevents the slide drive member20from sliding off the shaft14distally.

Referring toFIGS. 2 and 5on one side of the shaft14is a rounded aperture80. The rounded aperture80corresponds in location to a recess82in the top surface of shaft14as shown inFIG. 5. The recess82bisects the wider portion27of slot24and has a rounded bottom surface. Located within the recess82and extending from the aperture80is a push button assembly70having a large diameter, external button portion76and a narrow diameter portion74that passes through the aperture80. The narrow diameter portion74has a depression75with a flat bottom. The narrow diameter portion74terminates at its other end in a large diameter member72having a slightly smaller diameter than the diameter of the rounded recess82. The large diameter member72has a flattened top surface73so that it is flush with the top surface of the shaft14when the large diameter member72is inserted within the recess82. The reverse end of the large diameter member72has a small depression77for receiving the end of a coil spring84a shown inFIG. 4.

The large diameter member72is placed within the recess82, so that the narrow diameter portion74crosses the wider portion27of the slot24at a right angle and extends through the rounded aperture80and the external button portion76is external to the shaft14. The depression75in the narrow diameter portion74is of a sufficient depth to permit the stop pin60depending from the slide drive member20to easily pass through the wider portion27of the slot24and over the depression75unobstructed by the narrow diameter portion74.

Within the recess82is a coil spring84having an end that fits within the small depression77of the large diameter member72. The coil spring84serves to bias the large diameter member72so that in its biased position, the large diameter member72blocks the wider portion27of slot24. The large diameter member72has a diameter that is sufficient to prevent the stop pin60from sliding over it. The external button portion76is at its greatest extension out of the rounded opening80when the large diameter member72is in the biased position and blocks the wider portion27of the slot24. To unblock the wider portion27of the slot24, the user simply presses the external button portion76of the button assembly70so that the coil spring84compresses and the large diameter member72moves further into the recess82. When the large diameter member72is positioned as far into the recess82as possible the depression75of the button assembly70is positioned directly beneath the stop pin60depending from the bottom surface of the slide drive member20so that the stop pin60can pass through the wider portion27of the slot24unobstructed.

It is appreciated that the rounded recess82may be placed at various locations along the shaft14so that the button assembly70contained therein may also be positioned at various locations along the shaft14beneath the slide drive member20. The position of the stop pin60depending from the slide drive member20may also be changed to correspond to the location of the button assembly70and the configuration of the slot24and the position of the wider portion27may also be modified accordingly without departing from the scope of the present invention. For example, the rounded recess82may be replaced along the shaft14so that it is located within the opening15and the threaded aperture17of the body12. In this position, the button assembly70in addition to controlling the displacement of the slide drive member20along the shaft14could also serve as a hinge and attachment means for the forward handle30replacing the pivot pin32as shown inFIG. 17.

Referring toFIGS. 5 and 6, the shaft14has a pair of rails62,63extending from either side of the shaft14which run parallel to the shaft14. The rails62,63have a bottom substantially flat surface64that is perpendicular to the sides of the shaft14as shown inFIG. 6. Near the distal end of the shaft14are forward notches65,66that provide a break in the continuity of the rails62,63. Positioned proximal to the forward notches65,66are rear notches69,71which similarly provide a break in the continuity of the rails62,63.

Referring toFIGS. 4 and 6, the distal end61of the slide drive member20engages a cutting/storage member50which is removably attached to both the shaft14and to the slide drive member20. The cutting/storage member50has depending sides51and52which are mirror images of each other. As shown inFIG. 4, near the distal end of the cutting/storage member50, the depending sides51,52each have forward rail-engaging members53,54respectively. Forward rail-engaging members53,54fit within the forward notches65,66of shaft14. Each of the forward rail-engaging members53,54has a top substantially flat surface68that is perpendicular to the depending sides51and52for engaging the bottom substantially flat surface64of rails62,63as shown inFIG. 6. Once the forward rail-engaging members53,54are engaged to the rails62,63, the cutting/storage member50is prevented from sliding upward as it moves along the shaft14.

Also located on each of the depending sides51,52of the cutting/storage member50are rear rail-engaging members56,57which are sufficiently spaced proximally from the forward rail-engaging members53,54so that when the forward rail-engaging members53,54are placed over forward notches65,66, the rear rail-engaging members56,57are directly over the rear notches69,71in the shaft14. The rear rail-engaging members56,57are identical to the forward rail engaging members53,54and similarly each have a top substantially flat surface68for engaging the bottom substantially flat surface64of rails62,63.

Referring toFIGS. 2 and 4, the proximal end of the cutting/storage member50has a male connection means55having grooves58on both sides of a key portion59. The male connection means55fits into a female connection means21located at the distal end61of the slide drive member20. The female connection means21has rails23for engaging the grooves58of the male connection means55and a notched area78for receiving the key portion59. The cutting/storage member50may be engaged to the slide drive member20by lowering the cutting/storage member50toward the slide drive member20so that the male and female connection means55and21slide into each other. To disengage the cutting/storage member50from the slide drive member20, the cutting storage member50is simply lifted out. As an alternative, the cutting/storage member50may also be attached to the slide drive member20in any number of conventional ways, such as by snap fit.

The cutting/storage member50is placed on the shaft14by aligning the forward rail-engaging members53,54with the forward notches65,66and by simultaneously aligning the rear rail-engaging members56,57with the rear notches69,71so that the male connection means55slides into and engages the female connection means21of the slide drive member20. In order to properly align the cutting/storage member50so that it may engage the shaft14, the slide drive member20must be positioned sufficiently proximal from the foot plate16.

The range of proximal to distal movement of the slide drive member20is controlled by the large diameter member72of the button assembly70. In its biased position, the large diameter member72is positioned in the wide portion27of slot24so that the distal edge79of the large diameter member72blocks the stop pin60and thus the slide drive member20from moving proximally along shaft14. The appropriate position of the slide drive member20for attaching the cutting/storage member50to the shaft14may only be achieved by sliding the stop pin60past the position of the distal edge79of the large diameter member72. In order to slide the stop pin60past the distal edge79, the button assembly70must be manually depressed toward the shaft14so that the large diameter member72is pushed into the recess82and is moved out of the wide portion27of slot24. As the forward handle30is biased forward by the spring means40and40a, the slide drive member20is moved proximately along the shaft14so that the stop pin60is positioned within the depression75of the narrow diameter portion74. With the stop pin60positioned within the depression75, the large diameter member72is pushed back within the recess and the coil spring84is compressed within the recess82of the shaft14.

Once aligned with the forward and rear notches65,66and69,71and engaged to the slide drive member20, the cutting/storage member50is in position to be pushed distally along shaft14by the slide drive member20toward the foot plate16. This is accomplished by squeezing the forward handle30to move the slide drive member20and the stop pin60distally so that the stop pin60is no longer within the depression75of the narrow diameter portion74, and the large diameter member72is returned to its biased position by the coil spring84. As the cutting/storage member50is engaged to the slide drive member20, the movement of the cutting/storage member50is responsive to the movement of the slide drive member20. As the cutting storage member50is moved distally the front and rear rail-engaging members53,54and56,57engage the rails62,63.

Once the cutting/storage member50engages the rails62,63of the shaft14, it may not be lifted out and the cutting/storage member50is locked to the shaft14. The proximal movement of the slide drive member20is stopped by the large diameter member72in its biased position which blocks the stop pin60from further proximal travel in the wider portion27of the slot24. To remove the cutting/storage member50from the shaft14, the stop pin60must be again positioned by the user so that it is within the depression75of the narrow diameter portion74. Thus, the cutting/storage member50may be locked or unlocked to the shaft14without the use of tools by simply pressing the button assembly70. Further, once the button assembly70is pushed and the forward handle34is advanced by the handle biasing means40and40a, the rongeur10remains receptive to the introductions or removal of the cutting/storage member50without the need to continue depressing the release button.

Further, the cutting/storage member50is secured to the shaft14by simply pulling the forward handle34securing the cutting/storage member50to the shaft14until the release button assembly70is again depressed. The button assembly70does not have to be redepressed to allow pin60to move distally as portion75is of sufficient length to support it when the slide drive member20is maximally proximal.

The cutting/storage member50opens into a storage chamber88which is bounded by upper and side walls44and85which are sharpened distally to form cutting edges22facing the foot plate16. The depending sides51,52of cutting/storage member50are recessed from the foot plate16for maximum bite since no cutting edge is required at the depending sides51,52. While the foot plate16may have a slight concave depression to allow for a cutting edge, it is to be understood that it is preferably substantially flat, without a cutting edge.

The storage chamber88extends along the interior of the cutting/storage member50at least partially toward its proximal end. The cross sectional area of the interior of the storage chamber88may be constant or may progressively increase from the distal end to the proximal end so that a number of successive bone fragments can more easily slide into the storage chamber88and stack up without jamming.

The rongeur10of the present invention is used in the conventional manner to bite bone or cartilage. The cut bone fragments are pushed by the foot plate16, one by one, into a stack within the storage chamber88of the removable cutting/storage member50after being cut and are not likely to fall back into the wound site because they are forced into the storage chamber88with considerable force and are prevented from jamming as the cross sectional area of the interior space of the storage chamber88either has parallel or divergent walls. Thus, it is not necessary that the cut bone fragments be removed during the surgical procedure, and bite after bite takes place, without the need to remove the rongeur10from the wound.

The side walls44and85of the cutting/storage member50have narrow slits86,87partially along the length of the cutting/storage member50. Once the cutting/storage member50is filled with cut pieces of bone, it is removed from the shaft14and a stylet or similar instrument may be inserted through the slits86,87to aid in the removal of the cut pieces from the storage chamber88containing the cut pieces.

Alternatively, the proximal end of the storage chamber88of the cutting/storage element50may also be open. During use, the distal end61of the slide drive member20may be used to block the open proximal end of the storage chamber88. Once the cutting/storage member50is removed from the rongeur10, the proximal end of the storage chamber88is open and a stylet may be used to push the cut bone fragments stored within the storage chamber88so that the fragments exit from the distal end or in reverse from the proximal end.

The use of a removable hollow cutting/storage member50permits a new sharp cutting edge to be provided for each operation as it may easily be replaced. Both the storage chamber88and the cutting edge22could be made of metal or any other suitable material such as, but not limited to, ceramic for the cutting edge22or a plastic (e.g. polycarbonate) for the storage chamber88.

In the preferred embodiment, the rongeur10has a body12that is approximately 7¼ inches in length; a cutting/storage member50that is approximately 3¼ inches in length and approximately ⅞ inches in height and approximately ⅜ inches in width; a slide drive member20that is approximately 3 9/16 inches in length and approximately 7/16 inches in height and approximately ⅜ inches in width; a rear handle13approximately 4⅞ inches in length and a front handle30approximately 4⅜ inches in length having a extension member33that is approximately ⅞ inches long; and a button assembly70having an overall length of approximately 7/16 inches.

It is appreciated that the cutting elements of the rongeur of the present invention need to be made of a material capable of forming a sharp cutting edge and serving the intended purpose of the rongeur. Such materials include, but are not limited to, metals, ceramics or composite materials. The remainder of the rongeur could be made of metal, plastic or a composite material suitable for the intended purpose, such that the entire rongeur could be disposable.

Referring toFIGS. 8 and 9, in a first alternative embodiment of the present invention, the rongeur10includes a removable and disposable straw90that is attachable to the bottom of a carriage member96. The carriage member96is similar in construction to the cutting/storage member50but does not have the storage chamber88and essentially acts as a housing for carrying the straw90. Straw90is a hollow member in the shape of a cylinder or may have any other shape suitable for use with rongeur10. At the distal end of the straw90is a sharp cutting edge92for cutting bone or other similar tissue. In this embodiment, the cutting/storage member50is actually a carrier member as the straw90does the actual cutting and storing of the bone. Prior to use, the straw90is inserted within the storage chamber88before the cutting/storage member50is placed on the shaft14. The hollow chamber94of the straw90functions to store the cut pieces of bone or cartilage. The stored cut pieces may be removed for future use in the same manner described above for the preferred embodiment.

The straw90is placed in the bottom of the carriage member96prior to placing the carriage member96on the shaft14. The straw90is held in place and is prevented from rotating by pins97,98which complement the grooves101,102in the straw90as shown inFIG. 9, and prevent any movement of the straw90within the carriage member96during the operation of the rongeur. Once the carriage member96is removed from the shaft14, the straw90is easily removable from the carriage member96.

The straw90is preferably made of metal or any other material which is capable of being sharpened and maintaining a sharp cutting edge92for multiple bites by the rongeur10. After the straw90is used and removed from the rongeur10, the cut pieces contained therein are removed and may be used for bone grafting purposes if desired. The relatively low cost of the straw90allows the straw90to be truly disposable.

Referring toFIGS. 10A and 10B, a second alternative embodiment of the rongeur10is shown with the intersection of the foot plate16and the shaft14having a groove29such that the distal end of the cutting/storage member50or of a straw90has an extension element38that complements the shape of the groove29and fits within the groove29. The extension element38may be made of the same material as the cutting/storage member50. As a result of the angled orientation of the foot plate16, when the rongeur is fully closed, the cutting/storage member50or the straw90tends to be forced up the inclination of the foot plate16which may result in damage to the cutting edge22or92. The combination of the groove29and the extension element38functions to prevent any upward excursion of the cutting/storage member50or straw90which would result in an overbite.

The operation of the rongeur10of the present invention is as follows:

The rongeur10is set in the “release position” by positioning the stop pin60within the depression75of the narrow diameter portion74of the button assembly70. This in accomplished by manually pressing the external button portion76of the button assembly70so that the large diameter member72moves out of the wider portion27of the slot24to compress the coil spring84. The stop pin60may now freely pass by the position of the distal edge79of the large diameter member72and to fit within the depression75. As the spring means40and40abias the forward handle30distally, the slide drive member20moves toward the foot plate16. With the stop pin60positioned within the depression75, the coil spring84is kept compressed within the recess82.

In the release position, the slide drive member20is positioned so that the cutting/storage member50may be easily placed on the shaft14. In the release position, the forward rail-engaging members53,54are aligned with the forward notches65,66and the rear rail-engaging members56,57are aligned with the rear notches69,71. Once aligned, the cutting/storage member50is positioned to easily engage the slide drive member20so that the male and female connector means55and21mate and the cutting/storage member50rests upon the shaft14.

Once the cutting/storage member50is engaged to the slide drive member20, the forward handle30is squeezed by the user to advance the slide drive member20so that the stop pin60exits from within the depression75and the large diameter member72is returned by the coil spring84to its biased position to block the wider portion27of the slot24. With the large diameter member72in this position, the stop pin60is stopped from any further proximal movement past the distal edge79of the large diameter member72thereby preventing any further proximal movement of the slide drive member20past the large diameter member72. With the slide drive member20in this position, the forward and rear rail engaging members53,54and56,57are engaged to the rails62,63and are no longer aligned with the forward and rear notches65,66and69,71. Therefore, the cutting/storage member50is securely locked to the shaft14and may not be removed from the shaft14.

With the cutting/storage member50in the locked position on the shaft14, the rongeur10may be placed in the wound and used to take multiple bites or cuts of the selected tissue with the cut pieces being stored within the storage chamber88of the cutting/storage member50. Once the desired number of bites has been attained or if the storage chamber88becomes filled, the rongeur10is removed from the wound. The cutting/storage member50is removed from the shaft14of the rongeur by returning the rongeur to the release position by pressing the external button portion76as described above, so that the forward and rear rail-engaging members52,54and56,57are once again aligned with the forward and rear notches65,66and69,71and no longer engage the rails62,63. The cutting/storage member50is then easily lifted up and away from the shaft14.

The cut pieces may be removed from the storage chamber88by inserting a stylet in the slits86,87in the side walls44,45of the cutting/storage member50and pushing the cut pieces out from the chamber. If an alternative embodiment of the cutting/storage element50is used where the proximal end of the storage chamber88is closed only during use, the cut pieces may be pushed out of either end of the storage chamber88. Similarly, if a disposable straw90is used, the cut pieces contained within the straw90may be removed by using a stylet to the push the cut pieces out of either the proximal or the distal end of the straw90which are both open when not in use.

Further, the improved surgical rongeur of the present invention may be powered by alternative power sources such as electricity, via a cord or battery supply, pneumatic power, or other power sources can be employed. In a powered rongeur, the finger grip of the rongeur can then be devoted to turning on and off the power supply source to drive the instrument. If gas or other fluid is used, a pressure relief valve is preferably incorporated within the fluid line to establish a limit pressure, which may be set to the maximum desired biting force to be delivered.

Referring toFIG. 11, an electrically powered rongeur200is shown. The rongeur200comprises a housing201having a grip202that is adapted for receiving a rechargeable battery pack204and related electronic circuitry206. The battery pack204is removably inserted into the grip202through an opening at the base of the grip202and has spring clips207on either side of the battery pack204which fit into corresponding openings208in the grip202and lock into place. The battery pack204is removed by depressing the spring clips207so that they are out of the openings208and the battery pack204is easily removed from within the grip202. It is appreciated that in a simple variation of this embodiment, the battery pack204itself may serve as a removably attachable handle instead of fitting within the grip202. In this manner the battery pack204may be easily replaced by the surgeon.

The battery pack204has contacts209for electrical coupling to an activation switch210. The activation switch210is operated by the depression of a trigger212and is electrically coupled to the electronic circuitry206via contacts209. The activation switch210is used for controlling the power supplied to a solenoid214located above the grip202and within the housing201. The solenoid214is electrically coupled to the electronic circuitry by contacts209. The rear portion of the housing201can be opened for access to the compartment by the removal of cap216which is threadably attached to the housing201. Prior to sterilization, the cap216and the solenoid214can be removed from the housing201. The rongeur200can be sterilized. It is appreciated that all of the electrical components of the electrical rongeur200may have contacts209such that the electrical components may be easily removed and replaced without the need for wiring these components.

The solenoid214drives a reciprocating rod210which is removably coupled at its distal end220to a cutting/storage member222and terminates in a proximal end portion224. The proximal end portion224is made of a non-ferrous material, such that the proximal end portion224is not affected by the electromagnetic field generated by the solenoid214. The rod218is spring biased by a strong spring226in the proximal direction to maintain the rod218in a maximally, proximal position and thus maintain a gap between the foot plate16and the cutting edge22of the cutting/storage member222. Near the proximal end portion224of the rod218is a plunger228having a bore230for receiving at least a portion of the proximal end portion224. The plunger228is made of a ferrous material such that the plunger228is responsive to the electromagnetic field generated by the solenoid210. When the solenoid210is powered, the plunger228is driven forward in the distal direction, driving the rod218in the same direction toward the foot plate16such that the cutting edge22of the cutting/storage member222contacts the foot plate16. The rod218is then returned to its proximal position by the spring226. The proximal travel of the plunger228is stopped by stopper232made of a resilient and sterilizable material such as an appropriate plastic well known by those skilled in the art.

As a safety precaution, the momentum at which the rod218is driven forward toward the foot plate16may be set to a desired rate, such that excessive force is not exerted on the cutting edge22and the foot plate16. Further, the rod218can be adjustable along the longitudinal axis, either by threads or other means, such that a precise closing of the cutting edge22against the foot plate16is achieved. In this manner, any other tendency of the cutting edge22to continue distally placing further stress on the foot plate16is avoided.

The depression of the trigger212closes the switch210to cause one closing and opening of the rongeur200. For a second closing operation, the trigger212must be released and then depressed again in order to close switch210once again. A safety mechanism for preventing activation of the switch210, well known in electrically operated devices, can be included. Such a safety mechanism could consist of a mechanical interference between the trigger and the switch to prevent activation of the switch210or a second trigger may be placed in a separate location on the grip202to insure that activation of the rongeur occurs only when both the trigger212and the second trigger are depressed to avoid accidental activation of the rongeur200.

Referring toFIGS. 11-14, the cutting/storage member222is a hollow tube for containing multiple cut pieces of bone or cartilage, having a sharp cutting edge22and an engagement end234for removably engaging the rod218. The cutting/storage member222is slidable within a shaft housing236which remains stationary as the cutting/storage member222reciprocates along the shaft238in rectilinear motion. Although the shaft housing236has been described and shown as being a single piece, it is appreciated that shaft housing236may comprise a number of separate pieces spaced apart along the shaft238while still being capable of housing the cutting/storage member222. Engagement end234is closed when in use, but once the cutting/storage member222is removed from within the shaft housing236, it is open such that bone may be pushed from one end of the cutting/storage member222out the other end with the use of an obdurator or other similar instrument.

The shaft housing236removably engages the shaft238in the same manner in which the cutting/storage member50(described above) removable attaches to shaft14as described in detail above. Like the cutting/storage member50, the shaft housing236has forward rail-engaging members53,54which fit within the forward notches65,66of shaft238and rear rail-engaging members56,57which are sufficiently spaced proximally from the forward rail-engaging members53,54so that when the forward rail-engaging members53,54are placed over forward notches65,66, the rear rail-engaging members56,57are directly over the rear notches69,71in the shaft238. The shaft housing236is then slid in the distal direction toward foot plate16, such that the forward rail-engaging members53,54and the rear rail engaging members become engaged to the rails62,63, and the shaft cover236is prevented from sliding upward and becomes locked to the shaft238.

Referring still toFIG. 11, to ensure that shaft cover236stays locked to the shaft238, a biasing spring240is located within the housing201and maintains the shaft housing236biased in a maximal distal position. During the removal of the shaft housing236, the shaft housing236is moved proximally to compress the biasing spring240and permit the shaft housing236to become disengaged from the shaft238.

Referring toFIG. 14, a top plan view of the connections between the cutting/storage member222and the rod218is shown. The engagement end234of the cutting/storage member222has a female connection means242comprising radiused portions244aand244bon both sides such that a corresponding male connection means246on the rod218fits into the female connection means242. The cutting/storage member222may be engaged to the rod218by removing the shaft housing236and then lowering the cutting/storage member222onto the shaft238so that the female and male connection means242and246, respectively, engage. The shaft housing236is then replaced and locked to the shaft238as described above. To disengage the cutting/storage member222from the rod218, the shaft housing236is disengaged from the shaft238by sliding the shaft housing236in the proximal direction to compress the biasing spring240, the shaft housing236is lifted off, and then the cutting/storage member222is easily lifted out.

In use, the surgeon would insert the rongeur200around the bone to be cut and the trigger212would be pulled. The pulling of the trigger212would cause the rod218and the cutting/storage member222to be driven forward to close against the foot plate16cutting the bone and the cutting/storage member222and the foot plate16are returned to their original open position regardless of the trigger212being released or left depressed. This occurs because the delivery of electrical current to the solenoid214is interrupted by the electronic circuitry206and the strong return spring226returns the cutting/storage member222and the foot plate16to their original open position. Releasing the trigger212would permit the cutting/storage member222to return to its open position. The surgeon would then move the rongeur200, without removing the rongeur200from the wound, to the next area of bone requiring biting, and again activate the trigger212and cause the rongeur200to close. The power rongeur200may be modified for use with any of the cutting/storage members described herein, such as the first embodiment described above in reference toFIG. 1.

Referring toFIG. 15, rongeur200ais shown which is an alternative embodiment of rongeur200. In this embodiment, rongeur200ahas a reciprocal rod218acoupled to the slide drive member20by a resilent compressible member221described in detail in copending application Ser. No. 07/398,987 filed on Aug. 28, 1989 incorporated by reference herein. The function of the rongeur200ais the same as described above for rongeur10, except that it is powered electrically. It is also appreciated that any of the embodiments of the rongeur of the present invention may be similarly adapted to become electrically powered without departing from the scope of the present invention.

The rod218ahas a non-ferrous portion260, a ferrous portion262, and terminates proximally in a threaded end portion264. Threadably attached to the threaded end portion264is a disc266which functions to stop the distal travel of the rod218aas it is advanced through the solenoid214by making physical contact with the solenoid214. As the disc266is threadably attached to the threaded end portion264, the distal travel of the rod218amay be regulated by varying how far the threaded end portion264is threaded into the disc266resulting in a change in the length of the rod218apassing through the solenoid214. To shorten the distance of the distal travel by the rod218a, the threaded end portion264is threaded further into the disc266. If a greater distance of travel of the rod218ais desired, the disc266is unscrewed such that less of the threaded end portion264is threaded into the disc266. In this manner, the force generated by the activation of the solenoid214is may be adjusted by varying the length of the rod218apassing through the solenoid214.

Referring toFIG. 16, an alternative embodiment of the power rongeur of the present invention is shown and generally referred to by the numeral300. The rongeur300comprises a primary solenoid302, a plunger304, a smaller secondary solenoid306, electronic circuitry307and a reciprocating rod308. The primary solenoid302, the secondary solenoid306and the electronic circuitry307are electrically coupled via contacts309to facilitate removal and replacement of those components without having to detach and reattach any wires. The reciprocating rod308has a proximal end comprising a first nonferrous portion310, a ferrous portion312, and a second nonferrous portion314. The secondary-solenoid306is much smaller and less powerful than the primary solenoid302. When the secondary solenoid306is activated, the electromagnetic field created urges the reciprocating rod308in the distal direction such that the ferrous portion312moves distally within the electromagnetic field of the secondary solenoid306. In this position, the reciprocating rod308is positioned in a distal direction sufficient to place the cutting edge22of the cutting/storage element236(shown inFIG. 11) in contact with the bone to be cut. It is important to note that the purpose of the secondary solenoid306is merely to advance the reciprocating rod308a sufficient distance to bring the cutting edge22in contact with the bone to be cut, but not to cut the bone.

Once the cutting edge22is properly positioned at the site in which a cut is desired through the activation of the secondary solenoid306, the primary solenoid302is activated and the plunger304is driven in the distal direction to provide a high impact force to the reciprocating rod308and the desired cut is performed. At that point in time, the delivery of electrical current to the primary solenoid302and the secondary solenoid304stops and the reciprocating rod308is then returned to its maximal proximal position by the biasing spring240regardless of whether the trigger212is released or left depressed. The plunger304is returned to its starting position by the spring313which is coupled to the removable cap315.

The supply of electrical current to the primary solenoid302and secondary solenoid306is controlled by a trigger316which closes an activation switch318having two stages. In the first stage, the trigger316is only partially depressed, such that the activation switch318delivers electrical current only to the secondary solenoid306for positioning the cutting edge22against the bone to be cut. The delivery of electrical current to the secondary solenoid306ceases immediately upon the release of the trigger316permitting the surgeon to reposition the rongeur300prior to cutting the bone. In the second stage, the trigger316is fully depressed such that the activation switch318delivers electrical current to the primary solenoid302while continuing to deliver electrical current to the secondary solenoid306.

The full depression of the trigger316causes one closing and opening of the rongeur300. For a second closing operation, the trigger316must be released and then depressed again in order to close switch210once again. It is appreciated that the first stage activation of the secondary solenoid306may be bypassed if a surgeon desires to make an immediate cut without first positioning the cutting edge22against the bone by fully depressing the trigger316at once to power the primary solenoid302.

Further, the electrical rongeur300may include a force adjusting means for adjusting the cutting force of the rongeur300. In one embodiment, such a force adjusting means may include an angled threaded opening350in the housing301for receiving a threaded member352therein. The threaded member352is threaded into the opening350such that the head354of the threaded member350sufficiently extends to limit the distal motion of the rod308by making contact with the oversized portion356of the rod308. It is appreciated that the further the threaded member352is threaded into the opening350the greater the limitation of the distal motion of the rod308and thus the lesser is the cutting force. It is further appreciated that the cutting force of the rongeur300can be limited electronically by controlling the amount of current that is delivered to the primary solenoid302. Such an electronic means is well known by those skilled in the art.

Referring toFIGS. 17-25, an alternative embodiment of a surgical rongeur made in accordance with the present invention is shown and generally referred to by the numeral400. The rongeur400is similar in structure to the rongeur10in the embodiment described above, except that it has an improved button assembly420and an improved cutting/storage member430.

Referring specifically toFIG. 17, the improved button assembly420functions to control the displacement of the slide drive member20along the shaft14in order to release or to engage the cutting/storage member430from the shaft14as described above. The improved button assembly420is located near the proximal end11of the shaft14and fits in the opening15to replace the pivot pin32. In this manner, the improved button assembly420also serves as a pivot pin and attachment means for front handle30.

Referring toFIG. 20, the improved button assembly420comprises a button member422having a large diameter portion424and a narrow diameter portion426with a threaded end427. The narrow diameter portion426fits through a hollow sleeve member428and threads to a substantially flat member440having a threaded opening441and is located on the opposite side of the body12of the rongeur400. The hollow sleeve member428acts as a bushing about which the front handle30pivots during the operation of the rongeur400. Between the button member422and the substantially flat member440is a coiled spring442that maintains the button member422in a biased position.

Referring toFIGS. 18 and 19, a front elevational view along lines18-18ofFIG. 17of the button assembly420in the biased position is shown. The substantially flat member440has a extension pin446that functions to limit the travel of the slide drive member20towards the proximal end11of the shaft14. In the biased position, the extension pin446is positioned such that it is between the top part448of the forward handle30and the body12to create space S so as to keep the slide drive member20in a more distal position. In this manner, the cutting/storage member430is engaged to the shaft14and is in the locked position as discussed above for the preferred embodiment of the surgical rongeur10.

Referring toFIG. 19, a front elevational view along lines18-18of the button assembly420is shown in the unbiased positioned that is achieved when the button assembly420is depressed in the direction indicated by arrow A. The top part448of the front handle30has a notch450capable of receiving at least a portion of the extension pin446when the button assembly420is in the unbiased position. In the unbiased position, the extension pin446no longer keeps the top part448of the forward handle30away from the body12of the rongeur400such that space S is eliminated and the slide drive member20is moved in a more proximal direction which allows the cutting/storage member430to be disengaged and removed from the shaft14. When the extension pin446is in the notch450, the button assembly420is prevented from returning to its normal biased position because the wall452of the notch450prevents the travel of the extension pin446in that direction.

When the front handle30is squeezed by the surgeon, the front handle30moves in the direction of the rear handle13and away from the body12of the rongeur400creating the space S between the top part448of the front handle30and the body12. In this position, the extension pin446is no longer contained within the notch450and moves, as result of the force of the coiled spring454, into the space S that is created between the top part448of the forward handle30and the body12of the rongeur400. Once the front handle30is released by the surgeon, the top part448of the front handle30rests against the extension pin446and is kept at a distance from the body12that is equal to the diameter of the extension pin446. As a result, the rongeur400is self-locking simply by the squeezing of the front handle30.

Referring toFIGS. 21 and 22, the improved cutting/storage member430is shown comprising a removable and disposable straw460which is a hollow member that is similar in structure to the straw90as described above. The distal end of the straw460is a sharp cutting edge462for cutting bone or other similar tissue. The straw460is affixed to the bottom of a slideable shaft housing470which is similar in construction to the carriage member96described above but has a straw engagement means472for removably engaging the straw460to the modified cutting/storage base470.

Referring toFIG. 23, an enlarged cross sectional view of the straw engagement means472is shown comprising a pivoting member474and a detent means476. The detent means476comprises a housing478for containing a spring means480for spring loading a detent ball482. A first end484of the pivoting member474is connected to the detent ball482and is maintained by the detent means476in a raised position or in a lowered position as shown in broken lines inFIG. 23. A second end486of the pivoting member474is capable of receiving the proximal end of the straw460and has a lip485so that the pivoting member474may be lifted to the raised position in the absence of a straw460in order to permit engagement of the straw460to the pivoting member474.

Referring toFIG. 24, a cross sectional view of the cutting/storage member430along lines24-24ofFIG. 22is shown. Extending from the second end486of the pivoting member474is a stabilizer pin488which fits into a corresponding opening490located near the proximal end of the straw460and functions to stabilize the straw460once the pivoting member474is inserted within the second end486of the straw460. The stabilizer pin488prevents rotational movement and distal movement of the straw460during the operation of the rongeur400.

Referring back toFIG. 21, the straw engagement means472functions to facilitate the attachment and the removal of the straw460to the shaft housing470. Prior to use, the straw460is placed in the shaft housing470so that it engages the pivoting member474in the raised position prior to placing the shaft housing470on the shaft14. Once the straw460is engaged to the straw engagement means472, the straw460is lowered towards the shaft housing470such that the straw460wedges into converging trapezoidal walls473A and473B and the detent means476keeps the straw460pressed into a stable wedged position, and prevents any movement of the straw460within the shaft housing470during the operation of the rongeur400.

To remove the straw460, once the shaft housing470is removed from the shaft14, the straw460is lifted away from the shaft housing470such that the pivoting member474is returned to its raised position. The surgeon then simply pulls the straw460away from the pivoting member474and engages a new straw460to the pivoting member474. The bone contained within the first straw460may then be harvested and the first straw460may then be disposed.

Referring toFIG. 25, an alternative embodiment of the straw engagement means500having a pivoting member510that pivots about an axis520and has a first end522with notches524aand524beach capable of receiving at least a portion of the detent ball530therein. The pivoting member510has the same function as the pivoting member474described above, and the notches524aand524bfunction to maintain the pivoting member510in the lowered or raised position, as described above for the straw engagement means472. As the pivoting member570pivots about the axis520, the detent ball530engages one of the notches524aor524bto hold the pivoting member570in a raised or lowered position. The pivoting member570has an extension pin588that has the same structure and function as the extension pin488described above and a lip585that has the same structure and function as the lip485described above.

Referring toFIG. 26, an alternative embodiment of the present invention is shown and generally referred to by the numeral600. The rongeur600comprises of a body610having a rear handle612depending at an angle from the proximal end614of the body610, and has an upper body portion616terminating into a removable cutting/storage element50. The upper body portion616is fixed and is capable of housing and slideably receiving a reciprocating shaft618which terminates in a foot plate16. The reciprocating shaft618is driven by a front handle620which is pivotably attached to the body610. The front handle620drives the reciprocating shaft618via a toothed gear622which engages a correspondingly toothed track624of the reciprocating shaft618while the body610remains stationary. In this embodiment, the cutting/storage element50remains in a fixed position while the shaft618reciprocates during the cutting action of the rongeur600to bring the foot plate16into contact with the cutting/storage member50.

Referring toFIG. 27, an alternative embodiment of the surgical rongeur of the present invention is shown and generally referred to by the numeral700. The rongeur700comprises a body712having a shaft714extending distally with a removable portion715. The removable portion715has its distal end terminating in a foot plate716and its proximal end having a double-key, male member718for engaging a corresponding female member720located at the distal end of the shaft714.

Referring toFIG. 27A, the male member718is shown fully seated within the female member720to provide a stable coupling capable of enduring the above-described forces encountered during the operation of the rongeur700. The removable portion715provides the added advantage of allowing the surgeon to easily replace at least a portion of the shaft714, such as the foot plate716, along with replacing the cutting/storage member if desired, as described in detail for the embodiments set forth above.

It is appreciated that an important advantage of the removable portion715is that multiple removable portions715of various sizes and lengths having various foot plates716can be made available to the surgeon appropriate for the particular surgical procedure being performed by the surgeon. In this manner the versatility of the rongeur700is greatly increased, the need for having multiple rongeurs of different sizes and configurations is eliminated greatly reducing cost, especially if the rongeur700is power actuated.

For example, the removable portion715may have a foot plate716that is angled relative to the shaft716in a specific orientation for a particular surgical procedure such that a number customized removable portions715may be provided for use with a common body, handle and shaft714. The removable portion715may have different lengths, diameters and the overall configuration of the removable portion715may be rounded for use in endoscopic procedures as described in reference toFIGS. 28 and 29set forth in detail below.

Further, the structure of the rongeur700allows for a variety of different sizes and configurations of removable portion715and foot plate716to be interchangeably utilized with a common handle, body, and shaft714. Additionally, the structure of the rongeur700allows for the replacement of both cutting edges—the cutting/storage member and the foot plate716—when it is desired to incorporate a cutting surface that is out of the plane of the surface730on the foot plate716sufficient to provide a cutting surface but not to hold a substantial amount of bone such that it would prevent the bone from being advanced into the cutting/storage member. When the foot plate716contains such a cutting surface, it is preferable that the entire removable portion715be disposable such that fresh, sharp cutting surfaces are provided with each use.

Referring toFIG. 27B, a partial side sectional view of an alternative embodiment of the rongeur700having a foot plate716awith a cutting surface740which is out of the plane of the surface730of the foot plate716afacing the cutting edge742of the cutting/storage member750is shown. The cutting surface740is slightly raised from the surface730such that the cutting surface730and the cutting edge742contact and mate during the cutting of bone or cartilage. The cutting edge742is preferably sharpened only on the interior side754of the cutting/storage member750.

Referring toFIG. 27C, an alternative embodiment of the foot plate716aofFIG. 27Bis shown and generally referred to by the numeral716b. The foot plate716bhas a cutting surface740awhich is out of the plane of the surface730facing the cutting edge742aof the cutting/storage member752. In this embodiment, the cutting surface740ais below the plane of the surface730such that the cutting edge742aof the cutting/storage member752is received within the cutting surface740a. The cutting edge742ais preferably sharpened on both the interior side754and the exterior side756such that the cutting edge742ais a knife-like edge.

Referring toFIGS. 28 and 29, an alternative embodiment of the surgical rongeur of the present invention for use in endoscopic surgical procedures is shown and generally referred to by the numeral800. The endoscopic rongeur800has a shaft814and a cutting/storage member850that are preferably rounded over their entire length, but may be more limitedly rounded in a particular area such as the area of the shaft and handle junction. The cutting/storage member850preferably has a straw890similar to the straw90described above in reference toFIGS. 8 and 9, and having a semi-circular cross section to maximize the biting and storage area of the endoscopic rongeur800. Such an overall rounded configuration facilitates the passage of the endoscopic rongeur800through the skin and flesh or as more commonly practiced through a cannula typically used for such endoscopic surgery to pass through the skin and soft tissue of the patient and into the abdomen, thorax, or within other areas of the body while still allowing for a good seal against gas or fluid leakage from within the body of the patient.

Referring specifically toFIG. 29, a cross sectional view of the endoscopic rongeur800is shown illustrating the overall circular diameter of the shaft814and cutting/storage member850. It is appreciated that in order to better form a seal with the opening in the body of the patient, the cutting/storage member850may be slideable within a fixed exterior housing, such as shaft housing236, described above for the embodiment shown inFIGS. 11-14. Such an exterior housing would also have an overall circular diameter. In this manner, once the endoscopic rongeur800is placed within the opening in the body, the seal formed between the fixed exterior housing and the opening of the patient is maintained relatively undisturbed.

The endoscopic rongeur800preferably has an overall length of approximately 13.0 inches (330.2 mm) to 18.0 inches (457.2 mm), with a shaft length measured from the foot plate to the handle of approximately 10.5 inches (266.7 mm) to 13.0 inches (330.2 mm), and a shaft diameter of approximately 3/16 inches (4.0 mm) to ½ inch (12.0 mm), and preferably ⅓ inch (8.0 mm).

It is appreciated that the endoscopic rongeur800can be activated manually by rear handle13and forward handle30described above, having an overall length of approximately 3.5 inches (88.9 mm) to 6.0 inches (152.4 mm). It is further appreciated that the endoscopic rongeur800may be power actuated by any of the power means described above in reference toFIGS. 11-16.

Referring toFIGS. 30-32, an alternative embodiment of the surgical rongeur of the present invention is shown and generally referred to by the numeral900. The rongeur900comprises a removable unit902which removably engages a body912. The removable unit902comprises a shaft914terminating in a foot plate916and a cutting/storage member950. The removable unit902has a pair of engagement members920and922which are identical and fit into corresponding slots924and924in the body912. Each of the engagement members920and922comprise a flexible upper tyne930and a flexible lower tyne932sufficiently spaced apart to permit the upper and lower tynes930and932to flex toward each other.

Near the proximal end of the engagement members920and922, each of the upper and lower tynes930and932have protuberances934aand934bon the external surfaces and radiused portions936aand936bon the interior surfaces to form a substantially circular recess938. The protuberances936aand936bfit into corresponding notches940aand940bformed in slot924.

Referring specifically toFIG. 31, engagement member920is shown being partially inserted into slot924with the upper and lower tynes930and932being flexed toward each other as a result of the protuberances934aand934bcontacting the walls of the slot924. Located at the end of the slot924is a detent means942comprising a barrel member946connected via shaft948to a tab member952situated within an opening956in the body912proximate the slot924. The detent means942is biased distally by spring954such that when the proximal ends of the upper and lower tynes930and932contact the barrel member946, the spring956compresses to permit the upper and lower tynes930and932to be further inserted into the slot924until the protuberances934aand934bcoincide in position with the notches940aand940brespectively. As the protuberances934aand934bare entering the notches940aand940b, respectively, the barrel member946forces apart the upper and lower tynes930and932, and the spring956biases the barrel member946distally into the recess938.

Referring toFIG. 32, engagement member920is shown fully inserted and seated within the slot924with the protuberances934aand934bfully seated within the notches940aand940b, respectively, and the barrel member946is fitted within the recess938to maintain the appropriate spacing between the upper and lower tynes930and932such that the protuberances934aand934bremain fully seated within the notches940aand940b, respectively, and the removable unit902is locked into place to the body912and can not be removed unless it is unlocked by the surgeon. The removable unit902remains locked to the body912for as long as the barrel member946is situated within the recess938.

To unlock the removable unit902from the body912, the tabs952for each of the engagement members920and922are moved in the proximal direction by the surgeon such that the barrel member946is removed from within the recess938and the upper and lower tynes930and932can be flexed toward each other as the removable unit902is pulled away from the body912such that the protuberances934aand934bexit the notches940aand940b, respectively.

The rongeur900provides the ideal means for having both cutting elements—the cutting/storage member950and the foot plate916—being replaceable when a second cutting element is present in the form of a raised and sharpened cutting edge on the foot plate916sufficient to provide a cutting edge but not to hold a substantial amount of bone such that it would prevent the bone from being advanced into the cutting/storage member950. When the foot plate916contains a cutting edge, it is preferable that the entire end unit902be disposable such that fresh, sharp cutting elements are provided with each use.

The rongeur900also provides the added advantages of having different sizes and configurations of the removable end unit902which can be used with the same body912increasing the versatility of the rongeur900, eliminating the need for having multiple rongeurs of different sizes and configurations and greatly reducing cost, especially if the rongeur900is power actuated.

For example, the end unit902may have a foot plate916that is angled relative to the shaft916in a specific orientation for a particular surgical procedure such that a number of specialized end units902may be provided for use with the body912. The end unit may have a shaft914and cutting/storage member950of different lengths, diameters and the overall configuration of the end unit902may be rounded for use in endoscopic procedures as described in reference toFIGS. 28 and 29. In such cases, the entire end unit902may be entirely disposable or the end unit902may comprise any of the cutting/storage members described above having a disposable portion such as the straw90described above in reference toFIGS. 8 and 9.

It is further appreciated that while the body912is shown with a manually operated handle, any of the embodiments of the power handles described above in reference toFIGS. 11-16may be modified to drive the rongeur900without departing from the scope of the present invention.

Referring toFIG. 33, an alternative embodiment of the rongeur of the present invention is shown and generally referred to by the numeral1000. Rongeur1000has a shaft1014and a cutting/storage member1050that are preferably rounded over their entire length, but may be more limitedly rounded in the area of the shaft and handle junction. The cutting/storage member1050preferably has a straw1090similar to the straw90described above in reference toFIGS. 8 and 9, except that it is in communication with a vacuum pump1092via a hose1094. The vacuum pump1092functions to evacuate any cut pieces of bone or cartilage and cogenerated debris from the straw1090resulting from the cutting action of the rongeur1000. The hose1094forms an airtight seal with the straw1090to prevent vacuum loss and any contamination of the wound with the cut pieces of bone or cartilage or cogenerated debris. The use of a vacuum pump1092or similar means well known by those skilled in the art in association with rongeur1000is especially advantageous when the rongeur1000is being used in endoscopic surgical procedures where the presence of cut pieces of bone or cartilage and/or cogenerated debris interferes with the endoscopic procedure.

While the rongeur1000has been described with the cutting/storage member1050having a straw1090in communication with the vacuum pump1092, it is appreciated that any of the embodiments of the cutting/storage member described above may also be modified to be in communication with vacuum pump1092or similar means well known by those skilled in the art to evacuate any cut pieces of bone or cartilage and/or cogenerated debris from the cutting/storage member without departing from the scope of the present invention. While the present invention has been described in association with the preferred embodiment and several alternative embodiments, it is recognized that other variations of the present invention may be made without departing from the scope of the present invention. Further, it is appreciated that any of the manually activated embodiments of the rongeurs described above may also be made to be electrically powered and similarly the electrically powered embodiment may also be made to be manually activated without departing from the scope of the present invention.