Abstract:
The present invention relates to an improved arrangement for limiting the force applied to tissue by a mounted pivotal clamp arm of the present clamp coagulator apparatus and providing the appropriate amount of force to correctly positioned tissue. The arrangement is desirably economical in configuration, and cooperates with the associated pivotal clamp arm to position and maintain the clamp arm in substantial alignment with an associated end-effector, notwithstanding normal manufacturing tolerances of the components.

Description:
RELATED APPLICATIONS 
       [0001]    This application hereby claims the priority of U.S. Provisional Application 61/191,181 filed on Sep. 5, 2008. U.S. Provisional Application 61/191,181 and US patent application for Improved Jaw filed on Sep. 4, 2009, US patent application for Improved Tissue Pad filed on Sep. 4, 2009, and US patent application for Ultrasonic Shears Actuating Mechanism filed on Sep. 4, 2009 are incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates generally to ultrasonic surgical devices, and more particularly to ultrasonic surgical clamp coagulator apparatus for coagulating and/or cutting tissue. 
       BACKGROUND OF THE INVENTION 
       [0003]    Ultrasonic surgical instruments are finding increasingly widespread application in surgical procedures by virtue of the unique performance characteristics of such instruments. Depending upon specific instrument configurations and operational parameters, ultrasonic surgical instruments can provide substantially simultaneous cutting of tissue and hemostasis by coagulation, minimizing patient trauma. In some ultrasonic instruments the cutting action is typically effected by an end-effector at the distal end of the instrument, with the end-effector transmitting ultrasonic energy to tissue brought into contact therewith. Ultrasonic instruments of this nature can be configured for open surgical use, or laparoscopic or endoscopic surgical procedures. 
         [0004]    Ultrasonic surgical instruments have been developed that include a clamp mechanism to press tissue against the end-effector of the instrument in order to couple ultrasonic energy to the tissue of a patient. Such an arrangement (sometimes referred to as an ultrasonic shears, ultrasonic clamp coagulator, or an ultrasonic transector) is disclosed in U.S. Pat. No. 5,322,055, incorporated herein by reference. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention provides an ultrasonically-actuated surgical instrument for cutting/coagulating tissue, including loose and unsupported tissue, wherein the ultrasonic actuated blade is employed in conjunction with a clamp for applying a compressive or biasing force to the tissue against the blade. The present invention provides the foregoing features, in one embodiment hereof, as an ultrasonic clamp coagulator accessory for a standard ultrasonic surgical system wherein the instrument may be particularly adapted for endoscopic surgery. 
         [0006]    A standard ultrasonic surgical system comprises essentially a generator, which contains a power source for generating an ultrasonic frequency electrical drive sinusoidal waveform such as described in U.S. Pat. Nos. 5,026,387 and 6,063,050 (incorporated herein by reference) and a handpiece, containing a transducer for converting such electrical signal into longitudinal mechanical vibration for coupling to a blade assembly. Examples of suitable transducers include piezoceramic transducers as described in U.S. Pat. No. 7,285,895 (incorporated herein by reference), magnetostrictive transducers, or other means of producing ultrasonic vibration. 
         [0007]    Examples of generators include Ethicon Endo-Surgery Generator 300 or Generator G-110 and the Covidien AutoSonix Generator Box. Examples of transducers, sometimes called handpieces, include Ethicon Endo-Surgery HP054 or HPBLUE and Covidien AutoSonix™ Transducer. 
         [0008]    The clamp coagulator accessory adapts this standard ultrasonic unit for use in conjunction with a clamp assembly whereby tissue, particularly loose tissue, may be clamped between a clamping jaw and the blade for cutting and coagulating the tissue. 
         [0009]    In one embodiment, an ultrasonic surgical apparatus is configured to permit selective cutting, coagulation, and/or clamping of tissue during surgical procedures. The apparatus includes a pivoting clam arm which may be selectively pivoted towards and ultrasonic end effector. During use, tissue may be compressed against the ultrasonic end-effector by the clam arm, thereby allowing the tissue to be clamped, cut, and/or coagulated. 
         [0010]    The apparatus may be configured such that the pivotal clamp arm of the clamping mechanism is maintained in substantial alignment with the ultrasonic end-effector. Recognizing that normal manufacturing tolerances can result in misalignment of the clamp arm and end-effector, one embodiment of the present invention includes a clamp arm mounting arrangement which provides a “self-centering” action which maintains the clamp arm in the desired alignment with the ultrasonic end-effector. This desired alignment is achieved even when components of the apparatus, including the pivotal clamp arm, are dimensioned within normal manufacturing tolerances. 
         [0011]    In accordance with one embodiment, the present surgical apparatus includes a housing, and an inner tubular sheath having a proximal end joined to the housing. The inner tubular sheath may be joined with the housing in a manner which allows for rotation of the inner tubular sheath relative to the housing. An outer actuating member is reciprocably positioned around the inner tubular sheath such that the outer actuating member may reciprocally move longitudinally along the inner tubular sheath. An operating lever may be mounted on the housing and configured to effect selective reciprocable movement of the outer actuating member with respect to the inner tubular member. 
         [0012]    An ultrasonic waveguide, or blade, is positioned within the inner tubular sheath, and includes an end-effector extending distally of a distal end of the outer tubular sheath. In order to couple tissue with the ultrasonic end-effector, the apparatus includes a clamp arm pivotally mounted on the distal end of the inner tubular sheath for pivotal movement with respect to the end-effector. In this fashion, tissue can be clamped between the clamp arm and the end-effector for creating the desired ultrasonic effect on the tissue. The clamp arm is also operatively connected to the outer actuating member so that reciprocable movement of the outer actuating member pivotally moves the clamp arm with respect to the end-effector. 
         [0013]    In one embodiment, a rotating member such as a spline knob may be mounted on the housing in order to allow the user to align the blade and other components. For example, notches may be located on the inside of a spline knob engage openings on the inner and outer tube and on the blade shaft to ensure rotational alignment of the said inner tube and outer tube with the blade. Said spline knob serves as a means of rotating said blade to achieve desired alignment. Said notches may be oriented with respect to the blade end-effector to adjust the orientation of the blade with respect to the clamp arm. 
         [0014]    In one embodiment, the clamp is actuated by a scissor-like grip created by a thumb lever movably located on the under side of the handle housing and a finger grip located at the proximal end of the ultrasonic wave guide. Said thumb lever may be connected to a metal lever extending upwards towards the waveguide. The metal lever may be connected to a yoke assembly that engages the slideable outer tube, thereby allowing proximal and distal sliding movement of the thumb lever to slide the outer tube proximally and distally respectfully. 
         [0015]    A pin may be received through a distal end portion of the outer tube to engage a flat or a curved camming portion of the proximal end of the clamp arm. Distal motion of the slideable outer tube creates a camming motion acting upon said clamp arm. Furthermore, the clamp arm may be pivotally mounted via two mounting pins located at opposite side of the proximal end of said clamp along the circumference near the center of the distal end of the non-slideable inner tube so that the motion of the pin on the camming surface results in an opening and closing of the jaw with respect to the ultrasonic blade. 
         [0016]    This camming surface of the clamp arm may be distal or proximal to said clamp arm pivot, improving alignment between the clamp arm and blade. Thus, in one embodiment, by significantly reducing or eliminating relative motion between the inner tube and the blade, damage and failures of the blade seal can be reduced or eliminated. 
         [0017]    In one embodiment, a yoke assembly may be provided and includes a force-opposing member that engages a pre-loaded force-limiting spring. When said movable thumb lever moves distally, moving the clamp arm into a clamped position, said metal lever engages the force-opposing member, engaging the force-limiting spring, thus preventing adverse forces from being applied to the jaw. 
         [0018]    In accordance with one embodiment of the present invention, the outer tubular sheath includes a clamp arm mount, generally at the distal end thereof, on which the clamp arm is pivotally mounted. In order to maintain the clamp arm in the desired alignment with the associated end-effector, the clamp arm mount may engage the clamp arm, so as to provide a “self-centering” action in cooperation therewith. This engagement, which is accommodated by longitudinally parallel surfaces of the clamp arm and clamp arm mount, may accommodate normal manufacturing tolerances of the components, particularly the clamp arm, while maintaining the clamp arm in substantial alignment with the ultrasonic end-effector. 
         [0019]    In accordance with one illustrated embodiment, the clamp arm mount may have a generally U-shaped cross-section. The clamp arm mount includes a pair of laterally spaced leg portions which engage the clamp arm. The longitudinal parallel surfaces guide the clamp arm while opening and closing to maintain the clamp arm in substantial alignment. Each leg portion may define a respective pivot opening for receiving an associated pivot pin for pivotal mounting of the clamp arm. The clamp arm may include a pair of integral pivot pins respectively positioned on laterally spaced portions of the clamp arm. The integral pivot pins are configured for respective pivotal mounting in the pivot openings defined by the leg portions of the clamp arm mount. 
         [0020]    In one embodiment, the clamp arm holds or includes a tissue pad located substantially along the tissue side of the clamp arm, which acts as a clamping surface against the blade (i.e. the side facing the end effector of the blade). Said tissue pad may have a planar, concave, or convex tissue engagement surface. Said tissue pad may be adhered to said clamp arm by means of a glue or intermediate layer containing one or more adhesive surfaces. Said tissue pad may also attach mechanically to said clamp arm by means, for example, of molding said tissue pad into a shape with one or more columnar standoffs projecting from the tissue pad extending through the clamp arm and terminating on the opposite, outer surface of the clamp arm and comprising one or more features that are substantially larger than the columnar portion of the standoff, engaging the outer surface of the clamp arm securing the tissue pad to the clamp arm. Furthermore, the clamp arm may comprise indented features to accept said substantially larger features of said columnar standoffs, further securing the tissue pad to the clamp arm. Said tissue pad may also attach mechanically to said clamp arm via a substantially V-shaped or T-shaped slot located on the tissue engaging side of said clamp arm. Said tissue pad may comprise a substantially V-shaped or T-shaped projection that would engage said V-shaped or T-shaped slot. Furthermore, said tissue pad may comprise one or more curved tissue stop pads located proximally from the parallel tissue engaging surface of the tissue pad. Said curved tissue stop pads may curve from a direction parallel to the blade engaging surface of said tissue pad to a direction greater than 30 degrees from parallel and preferably substantially perpendicular to the orientation of the blade and act as an additional tissue grasping and manipulating surface. 
         [0021]    Other features and advantages of the present invention will become readily apparent from the following detailed description, the accompanying drawings, and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a perspective view of an ultrasonic surgical instrument system. 
           [0023]      FIG. 2  is a side view of one embodiment of ultrasonic shears disclosed herein. 
           [0024]      FIG. 3  is a perspective view of the ultrasonic shears of  FIG. 2 . 
           [0025]      FIG. 4  is a side section view of the ultrasonic shears of  FIG. 2 . 
           [0026]      FIG. 5  is a detailed side view of the housing of the ultrasonic shears of  FIG. 2 , with the left housing removed. 
           [0027]      FIG. 6  is a side view of the ultrasonic shears of  FIG. 2 . 
           [0028]      FIG. 7  is a side view of one embodiment of the end-effector of the ultrasonic shears of  FIG. 2 . 
           [0029]      FIGS. 8A and 8B  are side section views of the end-effector of  FIG. 7 . 
           [0030]      FIGS. 9A and 9B  are perspective section views of the end-effector of the ultrasonic shears disclosed herein. 
           [0031]      FIGS. 10A and 10B  are perspective section views of the end-effector of the ultrasonic shears disclosed herein. 
           [0032]      FIGS. 11 through 13  show the motion of the ultrasonic shears instrument including the force-limiting mechanism disclosed herein. 
           [0033]      FIG. 14A  is a perspective view of the end-effector, actuating tube, spline knob assembly disclosed herein. 
           [0034]      FIG. 14B  is a perspective view of the spline knob assembly with one half of the spline knob removed. 
           [0035]      FIG. 14C  is a side view of the spline knob assembly with one half of the spline knob removed. 
           [0036]      FIGS. 15A and 15B  are section views of the spline knob assembly disclosed herein. 
           [0037]      FIGS. 16 and 17  are exploded perspective views of the ultrasonic shears instrument disclosed herein. 
           [0038]      FIGS. 18A ,  18 B, and  18  C are side, bottom and isometric views of a clamp arm with tissue gripping feature 
           [0039]      FIGS. 19A and 19B  are side and isometric views of an end effector with clamp arm containing a compliance member. 
           [0040]      FIGS. 20A and 20B  are a side view and a perspective view, respectfully, of an ultrasonic instrument end effector including tissue pad securing features. 
           [0041]      FIGS. 21A ,  21 B, and  21 C are a side view, a top view, and a section view, respectfully, of a clamp arm including tissue pad securing features. 
           [0042]      FIGS. 22A ,  22 B, and  22 C are a side view, a top view, and a section view, respectfully, of a clamp arm including tissue pad securing features 
           [0043]      FIGS. 23A and 23B  are a side view and a perspective view, respectfully, of a clamp arm including tissue grasping features. 
           [0044]      FIGS. 24A and 24B  are a side view and a perspective view, respectfully, of a clamp arm including tissue pad securing features. 
           [0045]      FIGS. 25A and 25B  are a side view and a perspective view, respectfully, of a clamp arm including tissue grasping features 
           [0046]      FIG. 26  is a cross section view of a clamp arm including tissue grasping features 
           [0047]      FIG. 27  is a list of all elements described herein. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0048]    The present invention will be described in combination with ultrasonic instruments as described herein. Such description is exemplary only, and is not intended to limit the scope and applications of the invention. 
         [0049]      FIG. 1  illustrates one embodiment of an ultrasonic system  10  for coagulating and/or cutting tissue. Ultrasonic system  10  may comprise an ultrasonic signal generator  50 , an ultrasonic transducer  20 , ultrasonic surgical apparatus  30 . In the embodiment shown in  FIG. 1 , ultrasonic surgical apparatus  30  is configured as ultrasonic shears for cutting and coagulating tissue. A torque tool  40  which may be used to secure ultrasonic shears  30  to ultrasonic transducer  20  is also shown in  FIG. 1 . 
         [0050]      FIGS. 2 and 3  further illustrate one embodiment of ultrasonic shears  30 . Ultrasonic shears  30  comprise a housing  65 , which may include a right housing  60  and a left housing  70 . Proximal of said housing is a movable thumb lever  110 , the thumb lever distal motion  420  of which is shown. Rotational movement  630  is also shown allowing for alignment of the end effector  176  during use. Clamp arm closing motion  620  is illustrated and is resultant of said thumb lever distal motion. 
         [0051]      FIG. 4  is a partial section view of ultrasonic shears  30 , illustrating the securing of ultrasonic transducer  20  onto the ultrasonic shears. In the embodiment shown, ultrasonic blade  220  is secured to transducer  20  using a threaded connection. This permits the transmission of ultrasonic vibration from ultrasonic transducer  20  to ultrasonic blade  220 . Alternative connection means providing a secure interface between ultrasonic transducer  20  and ultrasonic blade  220  may also be used. 
         [0052]      FIG. 5  illustrates the handle portion of shears  30  with left housing  70  hidden to reveal the inner workings. Shown is the right housing  60  of the ultrasonic shears  30 , which includes finger grip  112 . Finger grip  112  and thumb lever  110  create a scissor grip movably located on the under side of the right handle housing  60 . Said thumb lever  110  connects to a linkage  80  operably connected to a yoke assembly  90  that engages the actuating outer tube  230 , thereby allowing proximal lever motion  410  and distal lever motion  420  of the thumb lever  110  to slide the outer tube with a proximal motion  510  and distal motion  520  respectively (see  FIG. 6 ). The yoke assembly  90  may include a force-opposing member  100  that engages a pre-loaded force-limiting spring  130 . Drive flange  140  transfers force from said yolk assembly to the outer actuating tube  230 . Spline knob  180  acts as a means of rotating shaft assembly  240  and thus ultrasonic blade  220  to achieve desired alignment. Sleeve  200  houses and compresses the distal portion of said spline knob  180 . Washer  190  acts as a rotation and thrust bearing for shaft assembly  240  and prevents backlash. 
         [0053]      FIG. 6  is a side view of the ultrasonic shears  30 , illustrating the relationship between the motion  400  of thumb lever  110  relative to the outer actuating tube  230 , clamp arm  150 , tissue pad  170  and the ultrasonic blade  220 . Proximal motion  410  of thumb lever  110  results in proximal motion  510  of outer actuating tube  230 , which results in the opening motion  610  of the clamp arm  150  relative to the ultrasonic blade  220 . Conversely, distal motion  420  of said thumb lever  110  results in distal motion  520  of said outer actuating tube  230 , which results in the closing motion  620  of said clamp arm  150  and tissue pad  170  relative to said ultrasonic blade  220 . 
         [0054]      FIG. 7  is a side closeup view of the end-effector  176  of the ultrasonic shears  30 . Outer actuating tube  230  operably connects to clamp arm  150  via actuating pin  232 . Non-actuating inner tube  160  is shown extending distally from inside said outer actuating tube  230 . Inner tube  160  remains stationary with respect to ultrasonic blade  220  and blade seal  222  (see  FIG. 8A ). Tissue pad  170  is shown connected to said clamp arm  150  to operably contact with ultrasonic blade  220  and tissue therebetween when in surgical use. Furthermore, said tissue pad  170  may comprise one or more tissue stop pads  172  located proximally from the blade engaging surface  174  of the tissue pad  170 . The tissue stop pads  172  may curve from a direction parallel to the blade engaging surface  174  of said tissue pad  170  to a direction between 30 degrees and substantially perpendicular to the orientation of the ultrasonic blade  220  and act to position and manipulate tissue and may act as an initial barrier to prevent tissue from engaging undesired portions of the blade  220  or clamp arm  150  during surgical use. Blade engaging surface  174  may be convex and/or conformal to blade end effector  178 . 
         [0055]    In one embodiment, tissue stop pads  172  may engage tissue while clamp arm  150  is in the open position. As clamp arm  150  closes, tissue stop pads  172  force the tissue in contact with the tissue stop pads  172  distally and downward against ultrasonic blade  220 . This stretches tissue across ultrasonic blade  200 , creating tension in the tissue for use when cutting and/or coagulating. Tissue tension aids in the speed of cutting and coagulation. 
         [0056]      FIGS. 8A and 8B  are side partial section views of the end effector  176  of the ultrasonic shears.  FIG. 8A  shows the end effector  176  with the clamp arm  150  in the open position.  FIG. 8B  shows the end effector  176  with clamp arm  150  in the closed position. Clamp arm  150  rotatably attaches via pivot pin  152  to non-actuating inner tube  160 . The axis of pivot pin  152  may be positioned above, below, or passing through the axis of ultrasonic blade  220 . Clamp arm  150  pivots about pivot pin  152  when outer actuating tube  230  slides distally or proximally, engaging actuating pin  232  which is mounted at the substantially distal end of the outer actuating tube  230  and extending through cam slot  154  and operably engaging cam surface  156 . Ultrasonic blade  220  extends through the interior of tube  160  and is engaged by tissue pad  170  which is connected to clamp arm  150  to facilitate clamping tissue between tissue pad  170  and ultrasonic blade  220 . If tissue stop pads  172  are positioned near ultrasonic blade  220 , they may perform a wiping action, clearing said ultrasonic blade of tissue upon opening and closing of clamp arm  150 . 
         [0057]    The profile and location of cam slot  154  and cam surface  156  may be selected to provide constant or variable mechanical advantage as actuating pin  232  moves distally or proximally. As clamp arm  150  rotates, the contact angle between cam surface  156  and actuating pin  232  provides a quantifiable mechanical advantage that can be chosen to meet the requirements for manipulating tissue for the position of clamp arm  150 . The profile of cam surface  156  may be straight, contain one or more curves, or any combination thereof. Cam surface  156  may also include indentions or protuberances to give sensory feedback as actuating pin moves along the surface. Cam slot  154  may be placed distal or proximal to pivot pin  152 . 
         [0058]    In one embodiment, a steeper angle with respect to the motion of actuating pin  232  will provide faster clamp arm  150  closing speed with lower mechanical leverage, while a shallower angle will provide slower clamp arm  150  closing speed with higher mechanical leverage. When outer actuating tube  230  is positioned as shown in  FIG. 8A , the contact angle is steep, providing faster closing speed than when outer actuating tube  230  is positioned as shown in  FIG. 8B . However, the mechanical advantage is greater in  FIG. 8B , allowing significant clamping force to be applied to tissue. 
         [0059]    In one embodiment, actuating pin  232  may be mounted at the substantially distal end of an inner actuating tube and extending through cam slot  154  and operably engaging cam surface  156 . Clamp arm  150  rotatably attaches via pivot pin  152  to non-actuating outer tube. Clamp arm  150  pivots about pivot pin  152  when inner actuating tube slides distally or proximally, engaging actuating pin  232 . 
         [0060]      FIGS. 9A ,  9 B,  10 A, and  10 B are alternate partial sectional views of said end effector  176  of said ultrasonic shears  30 . Shown is blade seal  222 , which does not move with respect to blade  220  and inner tube  160 . Blade seal  222  may be bonded to ultrasonic blade  220  or inner tube  160 . Alternately, blade seal  220  may be held in place through mechanical means. Reducing or eliminating the relative motion of blade seal  222  with respect to ultrasonic blade  220  and inner tube  160  allows for a tighter seal and reduces wear. This further reduces potential fluid migration along the shaft of blade  220  inside inner tube  160 . Fluid along the shaft of blade  220  can produce unwanted and potentially dangerous heat as ultrasonic energy is damped out by the fluid. Reducing fluid migration reduces parasitic diversion of ultrasonic energy from blade  220  into waste heat, which can result in patient injury in some circumstances. By moving actuating tube  230  rather than inner tube  160 , the risk of patient injury can be reduced. Seal integrity is further enhanced by locating blade seal  222  with respect to blade  220  and inner tube  160  during manufacture of ultrasonic shears  30 . 
         [0061]      FIGS. 11A and 11B  illustrate partial section views of the ultrasonic shears  30 . The clamp arm  150  is actuated by a scissor-like grip created by a thumb lever  110  movably located on the under side of the right handle housing  60  and finger grip  112  located at the proximal end of the ultrasonic blade  220 . Said thumb lever connects to a linkage  80  operably connected to yoke assembly  90  that engages the actuating outer tube  230 , thereby allowing proximal and distal sliding movement of the thumb lever to slide the outer tube proximally and distally respectfully, resulting in the opening and closing movement of said clamp arm. 
         [0062]      FIGS. 12A and 12B  further illustrate the actuating motion of the ultrasonic instrument. Said elements described above actuate upon living tissue  300  in the manner described. Relative motion of finger grip  112  with respect to lever  110  produces motion in clamp arm  150  with respect to blade  220 . In the embodiment shown, distal motion  420  of thumb lever  110  results in distal motion  520  in outer actuating tube  230  producing closing motion  620  of clamp arm  150  and tissue pad  170 , thereby compressing tissue  300  against blade  220 . 
         [0063]      FIGS. 13A and 13B  further illustrate the yoke assembly  90  which includes a force-opposing member  100  that engages a pre-loaded force-limiting spring  130 . When slideable thumb lever  110  moves distally, moving said clamp arm  150  into a clamped position, linkage  80  engages the force-opposing member, engaging the force-limiting spring, thus preventing adverse forces from being applied to the clamp arm or the tissue  300  shown clamped between said clamp arm and said ultrasonic blade. Continued distal motion  420  on thumb lever  110  results in spring compression  132 , limiting the force applied to tissue  300 . By careful selection of the point of farthest travel by the said actuating tube and the preload of the said force-limiting spring  130 , the tissue can be compressed and transected with a clamping force within a desirable range. 
         [0064]    In one embodiment, force-limiting spring  130  is a helical spring. Force limiting spring  130  may also be any of the following types of springs: a cantilever, coil, conical, volute, leaf, V-spring, Belleville, disc, constant-force, gas, mainspring, elastomeric, washer, torsion, extension, wave or other deformable component. 
         [0065]      FIG. 14A  illustrates the shaft assembly  240  of one embodiment of the ultrasonic shears apparatus. Drive flange  140  transfers force from the above-described yolk assembly to the outer actuating tube  230 . Spline knob  180  acts as a means of rotating said shaft assembly, and thus ultrasonic blade  220  to achieve desired alignment. Sleeve  200  houses and compresses the distal portion of said spline knob. Torque tab  210  engages the torque tool  40  to secure or disconnect the ultrasonic shears instrument to the ultrasonic transducer  20 . Compliance feature  234  is created by notches which allow the outer actuator tube  230  to compress when significant axial load is applied. Notches may alternate or form a spiral pattern. By careful selection of the point of farthest travel by the said actuating tube and the preload of the said compliance feature  234 , the tissue can be compressed and transected with a clamping force within a desirable range. 
         [0066]      FIGS. 14B and 14C  are a perspective view and a side view, respectfully, of one embodiment of the spline knob assembly with washer  190 , sleeve  200 , blade  200 , and one half of the spline knob  180  removed, showing torque tabs  210 . Tabs  182  located on the inside of a spline knob engage inner tube openings  186  and outer tube openings  188  on the non-actuating inner tube  160  and outer actuating tube  230  and recesses  184  on the ultrasonic blade  220  to ensure rotational alignment of the said inner tube and outer tube with the blade. Said spline knob serves as a means of rotating said blade to achieve desired alignment. Said tabs and recesses are oriented with respect to the blade end-effector  178  to adjust the orientation of the blade end effector  178  to the clamp arm. Sleeve  200  acts to house said spline knob and the blade and tube assembly as well as secure washer  190 , which acts to securely locate said shaft assembly within the ultrasonic shears instrument handle assembly. Sleeve  200  compresses said spline knob, compressing tabs  182  into recesses  184 , substantially aligning the features. Cross section  242  intersects the assembly for purposes of illustration in  FIGS. 15A and 15B . 
         [0067]      FIGS. 15A and 15B  illustrate cross sectional views of the spline knob assembly with outer actuating tube  230  in different positions. 
         [0068]      FIG. 16  is an exploded view of the ultrasonic shears apparatus showing some of the previously described components and subassemblies of one embodiment. 
         [0069]      FIG. 17  is an exploded view of one embodiment of the ultrasonic shears shaft assembly showing components and features unobstructed by outer components of one embodiment. 
         [0070]      FIGS. 18A ,  18 B, and  18 C illustrate one embodiment of a clamp arm  150  having integral tissue grip features  158 . Clamp arm  150  and tissue pad  170  may be made from a metal and a polymer respectively. Tissue grip features  158  are designed to prevent tissue from slipping while being manipulated. Said tissue grip features may be any non-smooth surface, including but not limited to teeth, bumps, ridges, holes, and knurls. Tissue grip features  158  made from metal will withstand wear and damage better than equivalent features on a polymer tissue pad  170 . Tissue pad  170  may be attached to said clamp arm and may or may not be designed to provide additional gripping force on tissue. The width of blade engaging surface  174  of tissue pad  170  may be the same or less than the width of clamp arm  150 . 
         [0071]      FIGS. 19A and 19B  illustrate an embodiment of clamp arm  150  which includes an integrated compliance member  134 . Said compliance member is operably connected to an actuator such as the outer actuating tube  230  and to said clamp arm. Said compliance member deforms when force is applied by said outer actuating tube, reducing the closing motion  620  when resistance is met. Said outer actuating tube is prevented from traveling beyond a set point, limiting the force that may be applied to said clamp arm. Said compliance member may be preloaded to prevent deformation until the said applied force is above a threshold. By careful selection of the point of farthest travel by the said actuating tube and the preload of the said compliance member  134 , the tissue can be compressed and transected with a clamping force within a desirable range. 
         [0072]      FIGS. 20A and 20B  illustrate an embodiment of an end effector  176  with a clamp arm  150  with a tissue pad  170  connected to said clamp arm via one or more tissue pad rivets  350  extending through the cross-sectional area of said clamp arm, terminating on the side opposite of tissue interaction of said tissue pad of said clamp arm. Said tissue pad rivets, for example, can be molded or inserted through said clamp arm and then heat processed so that said tissue pad rivets form a substantially larger, opposing surface on said side opposite of tissue interaction. 
         [0073]      FIGS. 21A through 21C  illustrate an embodiment of clamp arm  150  which includes tissue pad rivets  350 . Cross section  352  is shown in  FIG. 21C . 
         [0074]      FIGS. 22A through 22C  illustrate an embodiment of clamp arm  150  which includes a tissue pad  170  including tissue pad connection member  360  extending substantially longitudinally along the length of said clamp arm and through the cross-sectional area of said clamp arm, terminating on the side opposite of tissue interaction of said tissue pad of said clamp arm. Said tissue pad connection member forms an enlarged, substantially flattened, opposing surface on said side opposite of tissue interaction. Cross section  362  is shown in  FIG. 22C . 
         [0075]      FIGS. 23A and 23B  illustrate an embodiment of clamp arm  150  which includes a tissue pad  170  including clamp arm projections  370  located on the surface of clamp arm  150 . Said clamp arm projections project through tissue pad  170  and may secure it through friction or mechanical interference. Said clamp arm projections also may interact with tissue creating an improved means of gripping tissue. 
         [0076]      FIGS. 24A and 24B  illustrate an embodiment of clamp arm  150  which includes a tissue pad  170  secured to said clamp arm via one or more opposing tissue pad securing tabs  380  located along the length of said clamp arm. Said tissue pad securing tabs also may interact with tissue creating an improved means of gripping tissue. 
         [0077]      FIGS. 25A and 25B  illustrate an embodiment of clamp arm  150  which includes tissue pad  170  located between tissue grip features  158  located along the length of said clamp arm. 
         [0078]      FIG. 26  shows cross section  392 . The width of blade engaging surface  174  of tissue pad  170  may be the same or less than the width of clamp arm  150 . Tissue pad  170  is held in place by means of a slot feature  390 . 
         [0079]      FIG. 27  is a list of all elements described herein. 
         [0080]    Thus, the described embodiments are to be considered in all aspects only as illustrative and not restrictive, and the scope of the invention is, therefore, indicated by the appended claims rather than the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.