Abstract:
An ultrasonic surgical instrument which incorporates a thumb and finger ring-actuated structure for the ultrasonic clamping device which is finger-operated in a scissor-like mode. Provided is either a fixed or removable blade tip and clamp assembly for ultrasonic treatments, so as to impart to the surgical instrument the ability of providing a variety of essentially exchangeable tips while reducing operationally engendered vibrations and stresses at the point of the coupling thereof to the clamp arm. The assembly is actuatable by relative movements between a blade extender and an outer tubular sheath extending to a handle end connected to the thumb and finger ring-actuated structure.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an ultrasonic surgical device which incorporates a readily detachable ultrasonic clamping device. In particular, the invention is directed to the provision of a removable blade tip and clamp assembly for ultrasonic treatments, so as to impart to the surgical device the ability of providing a variety of essentially exchangeable tips while reducing operationally engendered vibrations and stresses at the point of the coupling thereof to the clamp arm.  
           [0003]    Ultrasonic surgical devices or instruments which include ultrasonically-operating shears require the employment of a clamping mechanism which clamps tissue between an ultrasonic blade and a clamp arm. The mechanism for actuating the clamping mechanism necessitates the installation of a movable inner tube which is adapted to activate the clamp arm, and a stationary tube on which the clamp arm pivots. These tubes considerably increase the expense of the surgical instrument the cost of which is passed on to the customer or medical practitioner, and ultimately to the patient. In contrast, the inventive surgical instrument is designed to eliminate unnecessary costly components while being capable of reducing the outer diameter of the instrument or device. There is also a need in the medical technology for an ultrasonic instrument which possesses a detachable tip structure in order to facilitate cleaning, disposal, or usage of various end effectors; such as the blade and clamp element. A problem is also encountered with current detachable tip instruments in that they have an excessive number of parts, rendering the tips cumbersome to construct, expensive to manufacture; and also difficult to assemble by various possibly semi-skilled personnel and medical practitioners.  
           [0004]    Although the medical technology is extensively concerned with the problems encountered in connection with the construction of ultrasonic clamping devices or surgical instruments of generally the type considered herein, various desirable constructive and functional aspects are clearly lacking in the current state-of-the-technology.  
           [0005]    2. Discussion of the Prior Art  
           [0006]    Terumasa Japanese unexamined patent application 9-38099 discloses an ultrasonic surgical instrument with a tip/clamp assembly located at the distal node of a blade extender. The clamp arm of the instrument is movable on an axial pin, whereas the tip end is detachable through the use of a threaded screw connection, whereby this connection facilitates the interchanging of the tips. Due to the housing being located at the node, the point of attachment for the interchangeable tips is not located at the node, whereby the clamp assembly is not connected directly to the waveguide, but rather is attached to a housing located at the distal node of the blade extender.  
           [0007]    Mitsumasa Japanese unexamined patent application 8-275952 discloses an ultrasonic surgical tool with a blade/clamp assembly which is affixed to the blade via a nodally mounted block. The clamp is held open by a resilient flexible material; whereas the outer tube may then be actuated over the clamp through the intermediary of a manually-operated assembly, such as a thumb and finger ring assembly for effectively closing the clamp which becomes ensheathed by the outer tube. The tip/clamp assembly may also be removed for cleaning/disposal by means of a threaded connection.  
           [0008]    Schad U.S. Pat. No. 5,676,678 is directed to the provision of a surgical instrument with a holder for various tips, wherein the holder is coupled to an inner tube, and with the holder being detachable from the inner tube of the surgical instrument. The coupling functions by using two snap legs which engage over the tip assembly to fix the holder; the snap legs possessing elastic qualities which facilitate the selective attachment and removal of the tip assembly. When the holder coupling is exposed, the outer tube is held in place against the pressure of a helical spring by engaging hook projections located in an undercut rim of the instrument. These projections may then be released to cover and protect the coupling.  
           [0009]    Schad German Patent 19 534 618 issued on Mar. 20, 1997 discloses a surgical instrument with jaw components whereby at least one jaw part is connected to an inner tube so that it can be actuated relative to an outer tube to which the jaws are pivotally mounted. The jaw part consists of a catch which inserts into a bore hole opening, and closing the jaw part is effected by rotating the latter around a transversely mounted pin connecting the jaw parts to the outer tube. The instrument is designed to be disassembled through the provision of a removable inner tube so as to facilitate cleaning or disposal thereof. This patented surgical instrument is designed for manual and electrical use rather than as an ultrasonic surgical device. In contrast, the present invention possesses a clamp/blade system which is more effective in ultrasonic devices.  
           [0010]    Hood U.S. Pat. No. 5,669,922 discloses an ultrasonic surgical instrument having an end assembly comprising an end hook which is threaded and screwed into complementary threads formed on or in an extender. The blade of the instrument has a step that is located at or proximate to the nodal location of the assembly. This patent discloses only a blade, whereas to the contrary, the present invention incorporates a clamp mechanism, and moreover locates the coupling of the clamp mechanism at the node. By locating the coupling of the clamp at the node, mechanism pursuant to the present invention, vibrations and consequently stresses acting on the coupling are reduced. The nodal placement of the coupling functions to decrease wear on the coupling and reduces the possibility of clamp arm/transverse mounted pin/blade movement due to ultrasonic vibrations.  
           [0011]    Davidson et al. U.S. Pat. No. 5,322,055 discloses an ultrasonic surgical apparatus comprising a housing, an ultrasonic element carried by the housing for generating ultrasonic vibration, a blade coupled to the ultrasonic element and a clamp which moves in opposition to the blade for use in clamped coagulation. The present invention patentably distinguishes thereover by including a removable tip area which is located in an anti-nodal region, a multitude of choices for the tube/lever closure of the clamping device, a disassembly capability and a construction possessing fewer parts.  
           [0012]    Finally, DiMatteo, et al U.S. Pat. No. 5,810,859 discloses an ultrasonic surgical instrument with a removable waveguide which is connected to the hub of an ultrasonic transducer handle. The hub is designed to enable a coupling member to apply a rotational torque to the hub of the outer sheath, which is to be transmitted to the waveguide in order to tighten it onto the mounting device of the handpiece assembly. In a preferred embodiment of the patent, the location of the connection of the waveguide and handpiece is at the node to reduce any wear and stress due to the ultrasonic vibrations. In contrast, the present invention features a nodal connection at the point of attachment of the movable end effector; whereas although the patent discloses an embodiment with a removable end effector, that embodiment does not provide any disclosure about the nodal location of the movable end effector (jaw) coupling. The nodal location of the movable end effector pursuant to the present invention, in contrast, reduces wear on the coupling and reduces the risk of the tip attachment loosening or becoming damaged and the blade becoming damaged due to ultrasonic vibrations.  
         SUMMARY OF THE INVENTION  
         [0013]    Accordingly, in order to overcome the drawbacks and limitations encountered in the prior art, the present invention discloses an ultrasonic surgical instrument featuring an easily detachable ultrasonic clamping device incorporating a thumb/finger ring assembly actuating a removable or fixed blade assembly within an outer tube. The instrument features a clamp arm located at the distal node of the instrument, which is actuated by means of a direct drive system. The invention also discloses the structure for a possible detachable blade assembly which is located at the anti-node.  
           [0014]    Among the advantages of the present invention there is included a thumb/finger ring assembly for controlling the amount of force applied to the instrument. A spring embodied in the limiter assembly absorbs excessive force which may be possibly applied by the physician so as to prevent potential breakage of the instrument. The present invention also features an actuating blade assembly which actuates within an outer tube. This system eliminates the need for an inner tube, while at the same time eliminating the inadvertent friction caused by instruments in the prior art actuated by outer tubes which rub on the trocar. This particular friction which is encountered in the prior art, reduces the “feel” by the surgeon or medical practitioner during activation of the instrument. Moreover, the elimination of an extra outer tube reduces the overall size or diameter of the instrument, so as to resultingly improve upon visualization. The detachable blade/tip/clamp assembly allows for easy cleaning, disposal, and quickly interchangeable tips. Though these are several embodiments of the latter, the present invention may also have these parts affixed to each other, thereby reducing the extra parts necessary to make an instrument capable of being disassembled. These fixed instruments are beneficial for use in surgical or medical procedures where an inexpensive, disposable instrument would be optimal in order to reduce healthcare expenditures. The location of the clamp arm at the node reduces vibration and stress due to ultrasonic vibrations, thereby reducing wear and the potential of any breakage of the clamp arm. The blade tip apparatus is located at or near the anti-node to transfer as much ultrasonic power as possible to the blade. A direct drive system connecting the clamp arm to the thumb/finger ring assembly of the instrument serves to provide the physician with controlled forceful blunt dissection. In effect, the novel ultrasonic surgical instrument offers a physician a system adapted to apply a more controlled force in both opening and closing of the clamp arm.  
           [0015]    Pursuant to a specific embodiments, the present invention uses a pin passing through the node and some method of grounding the clamp to the tube, in the case where the blade is moving relative to the tube. In the case where the tube is moving relative to the blade, the blade/clamp interface is ground and there is force transmission from the tube to the clamp. Opening and closing could be facilitated through either blade movement relative to the tube or tube movement relative to the blade. Both movements would be initiated by the user via a manually-operated assembly, such as a thumb/finger ring assembly. The thumb and finger ring-actuated control system of the present invention provides the surgeon, physician or other medical practitioner, such as a nurse with greater control and reliability. The present invention also incorporates a direct drive system as opposed to the spring system of Mitsumasa Japanese &#39;952. One embodiment of the present invention provides a screw-in connection that consists of a single contained piece (such as the blade tip and clamp) that may be easily removed or attached. The screw-in connection provides for faster interchange or removal of tips and reduces overall part costs. However, other attachment methods may be utilized such as by means of magnaforming, press fit, swaging, and so forth; which methods are specifically directed to the provision of non-removable tips.  
           [0016]    Accordingly it is an object of the present invention to provide an improved ultrasonic surgical instrument which incorporates an easily detachable and replaceable ultrasonic clamping device.  
           [0017]    Another object of the invention resides in the provision of an ultrasonic surgical instrument possessing a unique attaching structure for the clamping blade and tip device which reduces stress and vibrations encountered due to ultrasonic vibrations so as to extend the service life of the instrument.  
           [0018]    Yet another object of the invention is to provide an ultrasonic instrument of the type described which employs a minimum number of easily assembled parts so as to render the instruments inexpensive to manufacture and render components of the instrument economically disposable and/or replaceable after only a single use.  
           [0019]    Still another object resides in the provision of an ultrasonic instrument of the type described which incorporates features rendering the instrument replaceable and/or disposable at a low cost after only a single use by the surgeon or medical practitioner. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    Reference may now be made to the following detailed description of preferred embodiments of ultrasonic surgical instruments pursuant to the invention, taken in conjunction with the accompanying drawings; in which:  
         [0021]    [0021]FIG. 1 illustrates a longitudinal view, partly in section, of a first embodiment of the ultrasonic surgical instrument pursuant to the invention;  
         [0022]    [0022]FIG. 2 illustrates, in a view similar to that of FIG. 1, a second embodiment of the inventive ultrasonic surgical instrument;  
         [0023]    [0023]FIG. 3 illustrates a detailed view of the blade extender and blade/clamp assembly of the instrument of FIG. 2;  
         [0024]    [0024]FIG. 4 illustrates a detailed view of an arrangement for attaching the blade/clamp tip portion of the instrument to a blade extender and tube;  
         [0025]    [0025]FIG. 5 illustrates, on an enlarged scale, the clamp/blade tip portion of FIG. 4;  
         [0026]    [0026]FIG. 6 illustrates a further embodiment of the actuator handle portion of an ultrasonic surgical instrument; and  
         [0027]    [0027]FIG. 7 illustrates a diagrammatic spring limiter arrangement for minimizing stress on the clamp/blade tip assembly of the instrument of FIG. 6.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0028]    Referring in detail to the drawings, FIG. 1 is a longitudinal sectional view of an ultrasonic surgical instrument  10  constructed pursuant to one embodiment. As shown, the ultrasonic surgical instrument  10  includes a coagulating accessory clamp arm  12 . Ultrasonic surgical instrument  10  comprises a handle-forming housing structure  14  including scissor-like operable thumb/finger ring assembly portion  16 ,  18  actuatable by the thumb and finger or multiple fingers of a user along arrow A. A blade extender  20  in the form of an elongated rod or shaft extends from the housing structure to an ultrasonic blade  21  which in this embodiment is integral therewith. A removable transducer (not shown) is located in the housing structure  14  and mounted removably to the proximal end of the blade extender  20 , and is preferably a piezeoceramic transducer for converting an electrical signal, for example, a 55,500 Hz sinusoidal waveform, into a mechanical longitudinal vibration. Handle structure  14  connects to an outer sheath or tube  22  coaxially covering the blade extender  20 , with the tube  22  having an end  24  fixedly attached to the housing structure, with blade extender  20  being axially slideable relative to tube  22 . In the embodiment of the ultrasonic surgical instrument  10  of FIG. 1, the thumb/finger ring assembly portion  18  is adapted to rotate around a pivot boss  28  on handle  14 , and is connected to the blade extender or shaft  20  by means of an insertion arm  30 .  
         [0029]    The clamp arm  12  connects directly in a pivoted manner to the ultrasonic blade  21  through the intermediary of a pin  32  about which the arm  12  may rotate. Though a pin  32  is used in this embodiment, there are numerous other means of hingedly or pivotably connecting the clamp arm  12  to the ultrasonic blade  21 , such as through a rivet, screw, or the like. The clamp arm  12 , which is attached to the ultrasonic blade  21 , then protrudes through a hole  34  formed in the tube  22 .  
         [0030]    During operation, wherein the thumb/finger ring assembly portion  18  of the handle is pulled towards thumb/finger ring portion  16  of handle part  14  in a finger actuated scissor-motion rotating around the cam surfaces of the pivot boss  28 , whereby the insertion arm  30  which is connected to the blade extender  20  either mechanically or by some mechanical transfer device (not shown), actuates the blade extender  20  distally so as to move axially within tube  22 . By actuating the blade extender  20  distally, the end of the clamp arm  12  which protrudes from a hole  34  is pulled backward against the wall of tube  22 . As the proximal end of clamp arm  12  is pushed forward, the clamp arm  12  rotates around pin  32 , rotating clamp arm  12  toward blade  21 . When the thumb/finger ring assembly portion  18  is pulled away from the handle portion  16 , the insertion arm  30  pivots around the cam surfaces of the pivot boss  28 , thereby actuating the blade extender  20  proximally. As the blade extender  20  moves proximally, the proximal end of the clamp arm  12  which protrudes through the hole  34  is pushed forward by the tube  22 . In doing so, the clamp arm  12  rotates around pin  32  rotating the distal end of the arm away from the blade.  
         [0031]    It is also possible to provide a reverse of this actuation with regard to the way in which the clamp arm  12  opens and closes, depending upon actuating direction in the thumb/finger ring assembly of the handle mechanism. The ultrasonic surgical instrument  10  may be built with the thumb/finger ring assembly portion  16  as the stationary actuator or with thumb/finger assembly portion  18  as the actuator mechanism, or reversely.  
         [0032]    In FIG. 2, in which elements similar to those in FIG. 1 are identified by the same reference numerals, there is illustrated a second embodiment in which a thumb/finger ring assembly  42  of the instrument  40  connects by means of an actuator attachment  44  to tube  46 . The assembly  42  is connected to a handle  48  through a pivot boss  50  about which assembly  42  pivots. In operation, the thumb/finger ring assembly  42  is pushed towards handle  48  rotating in directions of arrow B about the pivot boss  50 . The actuator attachment  44  is connected to the outer tube  46  by projecting into a slot  52  such that the latter pivots counterclockwise around pivot boss  50 , pulling the tube  46  proximally. As the tube  46  moves at its further or distal end, clamp arm  12  is pulled towards blade  21  as it pivots around pin  32 . When the assembly  42  is pulled away from handle  48 , the actuator attachment  44  pivots distally around the pivot boss  50 , whereupon as the actuator attachment  44  pivots, and the outer tube  46  is also pushed distally. As the tube moves distally, it resultingly pushes against the proximal end of the clamp arm  12  protruding though a small hole  34 . This produces the effect of rotating the clamp arm  12  around the pin  32  and pushing the clamp arm  12  away from the blade  21 .  
         [0033]    As shown in FIG. 3, rings  38  are formed from a silastic material and spaced along the length of the blade extender  20  and ultrasonic blade  21  at the nodes thereof so as to prevent the dispersion of ultrasonic waves to the tube  22 .  
         [0034]    As illustrated in the embodiment of FIG. 4, the tip portion  60  of the ultrasonic surgical instrument  10  or  40 , of either FIGS. 1 and 2, may be formed as a separate element from the blade extender or shaft  20  rather than being integral therewith. In this instance, the tip portion  60 , which comprises the blade  21  pivotally connected by pin  32  to the clamp arm  12 , as shown in detail in FIG.  5 , has the blade  21  equipped with a screw threaded end  62 , which is adapted to threadingly engage a complimentary screwthread  64  formed in the end  66  of the blade extender  20 . This construction allows for easy removal and exchange of the tip portion  60 , without requiring the entire instrument to be replaced. Other types of connections, in which the tip portion  60  is non-removable, can also be provided, such as by pin locks, interference fit, magnaforming or the like.  
         [0035]    Referring to the schematic representation of FIG. 6, this shows the provision of a latching pushbutton  70  on the handle structure  14  of the ultrasonic surgical instrument  10  of FIG. 1, which is connected to the blade and clamp (FIG. 3), which allows for the release of the disposable blade and clamp subassembly. Depressing the pushbutton  70 , which may be spring-loaded, releases the blade and clamp subassembly for easy cleaning or replacement.  
         [0036]    In FIG. 7, a spring limiter system  76  which is located on the tube  46  acts to minimize stress transmitted to the blade assembly  60  by absorbing any excessive force applied by the physician to thumb/finger ring assembly portions  16  or  18 . The spring limiter system  76  is located near the proximal end of the ultrasonic surgical instrument  40  adjacent to the handle structure  48 .  
         [0037]    While the invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.