Abstract:
An improved articulation mechanism is described in conjunction with a therapeutic ultrasound instrument. Ultrasonic vibrations, when transmitted to organic tissue at suitable energy levels and using a suitable end-effector, may be used for the safe and effective treatment of many medical conditions. The mechanism includes an actuating arm with a collar operatively connected to the actuating arm. The collar converts rotation of the actuating arm into a plurality of actuations of the surgical instrument. In one embodiment the collar includes two ranges of motion, where the first range is used to articulate the surgical instrument, and the second range is used to actuate the surgical instrument. Such instruments are particularly suited for use in minimally invasive procedures, such as endoscopic or laparoscopic procedures.

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 09/255,519 filed Feb. 22, 1999, now U.S. Pat. No. 6,090,120, which is a divisional of U.S. patent application Ser. No. 09/059,072, filed Apr. 13, 1998 now U.S. Pat. No. 5,897,523. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates, in general, to surgical instruments and, more particularly, to an articulation and actuation mechanism for surgical instruments. 
     BACKGROUND OF THE INVENTION 
     This application is related to the following copending patent applications: application Ser. No. 08/770,550 filed Dec. 23, 1996; application Ser. No. 08/808,652 filed Feb. 28, 1997; application Ser. No. 091255,519 filed Feb. 22, 1999; and application Ser. No. 09/464,973 filed Dec. 16, 1999 which are hereby incorporated herein by reference. 
     Ultrasonic instruments, including both hollow core and solid core instruments, are used for the safe and effective treatment of many medical conditions. Ultrasonic instruments, and particularly solid core ultrasonic instruments, are advantageous because they may be used to cut and/or coagulate organic tissue using energy in the form of mechanical vibrations transmitted to a surgical end-effector at ultrasonic frequencies. Ultrasonic vibrations, when transmitted to organic tissue at suitable energy levels and using a suitable end-effector, may be used to cut, dissect, or cauterize tissue. Ultrasonic instruments utilizing solid core technology are particularly advantageous because of the amount of ultrasonic energy that may be transmitted from the ultrasonic transducer, through the waveguide, to the surgical end-effector. Such instruments are particularly suited for use in minimally invasive procedures, such as endoscopic or laparoscopic procedures, wherein the end-effector is passed through a trocar to reach the surgical site. 
     Solid core ultrasonic instruments adapted for use in surgery and, more particularly, for use in minimally invasive surgery, are well known in the art. For example, U.S. Pat. No. 5,322,055 illustrates an ultrasonic surgical shears that utilizes solid core ultrasonic technology, while U.S. Pat. No. 5,324,299 illustrates an ultrasonic hook blade end-effector for use in surgical applications. In addition, articulating instruments for use in minimally invasive surgery are also known in the art. For example, U.S. Pat. No. 5,409,498 describes an articulating endocutter for use in cutting and stapling tissue. 
     Many ultrasonic surgical instruments used for cutting and coagulation rely upon relatively stiff, solid core ultrasonic waveguides to efficiently deliver energy from the transducer to the end-effector. In such instruments it may be desirable to articulate the end-effector in order to provide the surgeon with flexibility in engaging hard to reach structures. However, the relatively stiff solid core ultrasonic waveguides and the limited structural space available in minimally invasive instruments make it difficult to design appropriate mechanisms for articulating end-effectors in such devices. One option, which is illustrated and described in U.S. patent application Ser. No. 08/770,550 previously incorporated herein by reference, involves separating the waveguide into two or more segments which may be moved independently to provide articulation. 
     Flexible high power ultrasonic surgical instruments are also available. Flexible ultrasonic surgical instruments such as atherosclerosis treatment devices, thrombolysis devices, or some stone crushing devices are typically thin wires encased in a polymeric sheath, are relatively flexible, and articulate if assisted with known flexible endoscopy articulation means. For example, U.S. Pat. No. 5,380,274 describes a flexible ultrasonic catheter, and U.S. Pat. No. 4,108,211 describes a flexible endoscope mechanism. 
     It would, therefore, be advantageous to design an improved mechanism for articulating and actuating surgical instruments. It would further be advantageous to design an improved mechanism for articulating and actuating surgical instruments wherein the end-effector is both rotatable and articulatable. It would further be advantageous to design an articulating solid core ultrasonic surgical instrument which could be passed through a trocar or other surgical access device and the end-effector could be articulated utilizing a handle positioned outside of the surgical access device. The present invention incorporates improvements to known ultrasonic surgical instruments to provide these advantages. 
     SUMMARY OF THE INVENTION 
     An improved actuation mechanism for a surgical instrument is described. The mechanism includes an actuating arm and a collar operatively connected to the actuating arm. The collar converts rotation of the actuating arm into a plurality of actuations of the surgical instrument. In one embodiment the collar includes two ranges of motion, where the first range is used to articulate the surgical instrument, and the second range is used to actuate the surgical instrument. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to organization and methods of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a perspective partial cutaway view illustrating a surgical instrument including an articulatable ultrasonic surgical shears according to the present invention, wherein the surgical instrument is illustrated in combination with an ultrasonic transducer; 
     FIG. 2 is an exploded perspective view of a surgical instrument according to the present invention; 
     FIG. 2A is a perspective view of the distal end of the ultrasonic waveguide illustrated in FIG. 2; 
     FIG. 3 is a perspective view of the rotation driver of the articulation and actuation mechanism shown in FIG. 4; 
     FIG. 4 is a perspective view of an actuation mechanism internal to the surgical instrument shown in FIG. 1; 
     FIG. 5 is a perspective partial view illustrating the distal end of the actuating arm of a surgical instrument according to the present invention; 
     FIG. 6 is a perspective view illustrating a distal portion of the waveguide collar of a surgical instrument according to the present invention; 
     FIG. 7 is a perspective view illustrating a proximal portion of the waveguide collar of a surgical instrument according to the present invention; 
     FIG. 8 is a side sectioned view sectioned through the articulation collar illustrating the ultrasonic waveguide surrounded by the articulation collar positioned within the inner-tube and outer-tube of the ultrasonic surgical shears in accordance with the present invention; 
     FIG. 9 illustrates the device of FIG. 8 in its articulated position; 
     FIG. 10 is a cutaway perspective view illustrating a distal portion of the surgical instrument according to the present invention with the end-effector in the articulated position; and 
     FIG. 11 illustrates the device shown in FIG. 10 with the end-effector in the articulated position and the end-effector sheared. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates a surgical instrument  10  including an end-effector, designated as a shear blade  38  that may be both articulated and actuated according to the present invention. In FIG. 1, surgical instrument  10  is illustrated in combination with ultrasonic transducer  12 . Surgical instrument  10  includes instrument handle  14 , ultrasonic transmission rod assembly  16  and ultrasonic shear blade  38 . Ultrasonic transducer  12  includes generator housing  17 , which may also be referred to as a handpiece, and power supply cable  20 . Ultrasonic transducer  12  houses transduction elements, preferably piezeoceramic elements, for converting an electrical signal, for example, a 55,500 Hz sinusoidal waveform, into a mechanical longitudinal vibration. A suitable ultrasonic handpiece is available from Ethicon Endo-Surgery Inc. in Cincinnati Ohio, as make ULTRACISION® and model HP051. Instrument handle  14  includes finger grip  22 , actuation trigger  24  and rotation knob  26 . 
     FIG. 2 illustrates the elements and interconnection of instrument handle  14 , ultrasonic transmission rod assembly  16  and ultrasonic shear blade  38 . Instrument handle  14  includes left housing half  42  and right housing half  44 . Left housing half  42  includes finger grip  22 . Actuation trigger  24  is rotatably mounted on pivot pin  46  between left housing half  42  and right housing half  44 . Actuation trigger  24  includes thumb ring  48 , pivot  50 , yoke  52 , yoke arms  54  and detent pins  56 . Driver collar  58  is positioned in yoke  52  and rotatably engaged by detent pins  56 . Driver collar  58  comprises drive teeth  71 , engageable with drive threads  69  of rotation driver  65 . Rotation knob  26  is rotatably positioned between left housing half  42  and right housing half  44  at the distal end of instrument handle  14 . Rotation knob  26  includes rotation disk  60 , rotation channel  62 , rotation drive tube  64  and rotation knob connector pin holes  66 . 
     In FIG. 2 ultrasonic transmission rod assembly  16  includes outer sheath  28 , ultrasonic waveguide  30 , and actuating arm  34 . Outer sheath  28  is affixed to ultrasonic waveguide  30 , actuating arm  34  and rotation drive tube  64  by rotation connector pin  68  which passes through rotation knob connector pin holes  66 , waveguide connector pin hole  70 , outer sheath connector pin holes  67 , and actuation arm connector pin slot  74 . Outer sheath  28  includes proximal tube  76 , and wrench flats  78 . Actuating arm  34  is positioned within and extends from the proximal to the distal end of outer sheath  28 . Actuating arm  34  includes actuation arm connector pin slot  74  and actuation slot  82  at the proximal end. Actuation arm  34  is adapted to engage rotation driver  65  via keys  83  and keyways  85 . Actuating arm  34  is positioned on ultrasonic waveguide  30  within outer sheath  28 . 
     In FIG. 2 ultrasonic waveguide  30  includes node isolator  88 , connector segment  86 , transmission segment  90 , pivoting node  93 , shear blade  38 , fixed node  91 , and articulation segment  92 . Articulation segment  92  is bounded by fixed node  91  at the proximal end thereof and pivoting node  93  at the distal end thereof. Pivoting node  93  is surrounded by waveguide collar  43  comprising an articulation collar  45  and an actuation collar  47 . Articulation segment  92  is generally thinner than transmission segment  90  and, more particularly, preferably has a diameter of 20 to 70 percent of the diameter of the narrowest portion of transmission segment  90 . In addition, or as an alternative, articulation segment  92  may include a bend or curve to facilitate rotational movement of pivoting node  93 . Rotation is facilitated by reducing the force required to bend articulation segment  92 . Ultrasonic waveguide  30  is preferably fabricated from a solid core shaft constructed out of material which propagates ultrasonic energy efficiently, such as a titanium alloy (e.g., Ti-6A1-4V) or an aluminum alloy. 
     FIG. 2A illustrates first arm  122  and second arm  124  extending from the distal portion of ultrasonic waveguide  30 . First arm  122  and second arm  124  are bifurcated from ultrasonic waveguide  30  near pivoting node  93 . This bifurcation may be accomplished by cutting the distal portion of ultrasonic waveguide  30  using a laser cutting tool, EDM machine, or other methods known in the art. During actuation of shear blade  38 , first arm  122  and second arm  124  may be made to move normally to their length in a scissoring action, cutting any tissue therebetween. 
     As illustrated in FIG. 3, rotation driver  65  includes drive threads  69 , latch  59 , and keys  83 . Latch  59  is insertable into actuation slot  82  of actuating arm  34  (see FIG.  2 ). Threads  69  are angled along the length of rotation driver  65  to cause rotation driver  65  to rotate as driver collar  58  is moved forward over rotation driver  65  as further illustrated in FIG.  4 . 
     FIG. 4 illustrates handle actuation mechanism  51  of surgical instrument  10 . In handle actuation mechanism  51 , actuation trigger  24  is pivotally connected to driver collar  58  by yoke  52 . Yoke arms  54  of yoke  52  spring load detent pins  56  in collar rotation channel  57 . The proximal end of ultrasonic waveguide  30  extends through central aperture  61  of rotation driver  65 . The proximal end of actuating arm  34  extends into collar central aperture  61 . 
     Referring to FIGS. 2 through 4, latch  59  of rotation driver  65  engages actuation slot  82  that is positioned at the proximal end of actuating arm  34 . The proximal end of ultrasonic waveguide  30  is rotationally and axially affixed to rotation knob  26  by rotation connector pin  68  that passes through rotation drive tube  64 . The proximal end of actuating arm  34  is rotatably affixed to rotation knob  26  by rotation connector pin  68  which passes through rotation drive tube  64  and actuation arm connector pin slot  74  of actuating arm  34 . Drive teeth  71  of driver collar  58  engage drive threads  69  of rotation driver  65 . As driver collar  58  is driven over rotation driver  65  by yoke  52 , actuating arm  34  is rotated within outer sheath  28 . Rotation of actuating arm  34  within outer sheath  28  may be independent of rotation of ultrasonic transmission rod assembly  16  as a whole. 
     FIGS. 5 through 11 illustrate how ultrasonic shear blade  38  is made to both articulate and shear through actuation of thumb ring  48  via handle actuation mechanism  51  (FIG.  4 ). In FIG. 5, the distal end of actuating arm  34  comprises thread tabs  29 A and  29 B and shear tabs  49 A and  49 B. Thread tabs  29 A and  29 B and shear tabs  49 A and  49 B may be formed from actuating arm  34  by processes such as, for example, cutting and forming the thread tabs  29 A and  29 B and shear tabs  49 A and  49 B from actuating arm  34 . Actuating arm  34  also comprises an opening  53 . 
     FIG. 6 illustrates the actuation collar  47  of the waveguide collar  43  of a surgical instrument  10  according to the present invention. Actuation collar  47  comprises tab faces  55 A and  55 B, contact lobes  73 A and  73 B, and a collar aperture  77 . Collar aperture  77  accommodates ultrasonic shear blade  38  to be positioned within and extend from actuation collar  47 . 
     FIG. 7 illustrates articulation collar  45 , the proximal portion of the waveguide collar  43 . Articulation collar  45  includes an attachment portion  102 , articulation portions  104  and  106 , bore  108 , and keyway  110 . Articulation collar  45  and actuation collar  47  are rotatably coupled, and work together to both articulate and actuate ultrasonic shear blade  38 , as will be described below. 
     FIG. 8 illustrates the distal end of surgical instrument  10  showing ultrasonic shear blade  38  in a non-articulated and non-actuated condition. Shear blade  38  extends straight and longitudinally from ultrasonic waveguide  30 . Ultrasonic waveguide  30  is located within actuating arm  34  by waveguide collar  43 . Actuating arm  34  is located within outer sheath  28 . Key  111  of ultrasonic waveguide  30  rigidly locates articulation collar  45  onto a nodal attachment point  114  of ultrasonic waveguide  30 . Attachment portion  102  of articulation collar  45  is shown coupled to groove  112  of actuation collar  47 . Articulation portions  104  and  106  are shown contacting thread tabs  29 B and  29 A respectively. 
     As illustrated in FIG. 9, articulation of ultrasonic end-effector  38  is achieved by rotation of actuating arm  34  about ultrasonic waveguide  30 . The distal end of surgical instrument  10  is illustrated with ultrasonic shear blade  38  in an articulated, but non-actuated condition. As thumb ring  48  is moved toward finger grip  22  (illustrated in Figure 2 ), drive teeth  71  are pressed over drive threads  69 , causing actuating arm  34  to rotate. Rotation of actuating arm  34  through the first (30) to (60) degrees articulates ultrasonic shear blade  38  (10) to (20) degrees from longitudinal axis  116 . After (30) to (60) degrees of rotation, articulation portions  104  and  106  change from an angled region  118 A and  118 B to non-angled regions  120  and  121 , as illustrated in FIG.  7 . Articulation of shear blade  38  is accomplished by bending articulation segment  92  of ultrasonic waveguide  30  as described in U.S. patent application Ser. No. 09/255,519 previously incorporated herein by reference. 
     Now referring to FIGS. 2,  6 , and  10 , the actuation of shear blade  38  is illustrated. As actuating arm  34  continues to rotate past (30) degrees to (60) degrees, actuation collar  47  causes shear blade  38  of ultrasonic shear blade  38  to shear. Actuation collar  47  rotates freely with articulation collar  45  until shear tabs  49 A and  49 B contact tab faces  55 A and  55 B respectively. As rotation continues, contact tabs  73 A and  73 B apply a force to shear blade  38 . 
     FIGS. 10 and 11 illustrate shear blade  38  moving from an articulated non-actuated state to an articulated actuated state. Shear tabs  49 A and  49 B contact tab faces  55 A and  55 B respectively and apply a force to shear blade  38  causing shear blade  38  to shear as illustrated in FIG.  11 . During actuation, contact tab  73 A forces first arm  122  in one direction, while contact tab  73 B forces second arm  124  in the opposite direction causing shear blade  38  to shear. Counter-rotation of actuating arm  34  then allows first arm  122  and second arm  124  to return to their original non-actuated state. 
     Referring back to FIG. 2, shear blade  38  may be both articulated and actuated by moving actuation trigger  24  of instrument handle  14  toward finger grip  22 . When actuation trigger  24  is moved toward finger grip  22 , pivot  50  of actuation trigger  24  pivots on pivot pin  46 , forcing yoke  52  to move toward the proximal end of instrument handle  14 . Proximal movement of yoke  52  is transmitted to driver collar  58  by yoke arms  54  and detent pins  56  which engage rotation driver  65 . Thus when actuation trigger  24  is moved toward finger grip  22 , driver collar  58  is moved axially in a distal to proximal direction over rotation driver  65 . 
     Axial movement of driver collar  58  is converted to rotation of rotation driver  65 , that subsequently rotates actuating arm  34  by applying a force through latch  59  which engages actuation slot  82  in actuating arm  34 . Actuation arm connector pin slot  74  in actuating arm  34  is elongated to ensure that rotation connector pin  68  and node isolator  88  do not interfere with the rotational movement of actuating arm  34 . Thus, distal to proximal axial movement of driver collar  58  forces actuating arm  34  to rotate and, since rotation driver  65  is free to move with respect to the proximal end of ultrasonic waveguide  30 , axial movement of actuating arm  34  does not result in axial movement of the proximal end of ultrasonic waveguide  30 . 
     In order to properly position shear blade  38  prior to or after it is articulated, surgical instrument  10  is also adapted to allow shear blade  38  to be rotated around a central axis. Axial rotation of shear blade  38  is accomplished by moving rotation knob  26 . When rotation disk  60  of rotation knob  26  is rotated, rotational force is transmitted through rotation drive tube  64  to rotation connector pin  68 . As illustrated in FIG. 2, rotation channel  62  is mounted between left housing half  42  and right housing half  44  such that rotation knob  26  may be freely rotated but will not move axially with respect to instrument handle  14 . Rotation connector pin  68  passes through rotation knob connector pin holes  66 , outer sheath connector pin holes  67 , mounting arm connector pin-slot  72 , waveguide connector pin hole  70  and actuation arm connector pin slot  74 , thus transmitting rotational forces from rotation knob  26  to outer sheath  28 , ultrasonic waveguide  30  and actuating arm  34 . Rotational forces are, in turn transmitted back to rotation driver  65  by the interconnection of actuation slot  82  and latch  59 . 
     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.