Patent Publication Number: US-11382642-B2

Title: Rotatable cutting implements with friction reducing material for ultrasonic surgical instruments

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional patent application is a divisional application claiming priority under 35 U.S.C. § 121 to U.S. patent application Ser. No. 15/249,860, filed Aug. 29, 2016, entitled ROTATABLE CUTTING IMPLEMENTS WITH FRICTION REDUCING MATERIAL FOR ULTRASONIC SURGICAL INSTRUMENTS, which issued on May 28, 2019 as U.S. Pat. No. 10,299,810, which is a divisional application claiming priority under 35 U.S.C. § 121 to U.S. patent application Ser. No. 13/891,269, filed May 10, 2013, entitled ROTATABLE CUTTING IMPLEMENTS WITH FRICTION REDUCING MATERIAL FOR ULTRASONIC SURGICAL INSTRUMENTS, which issued on Aug. 30, 2016 as U.S. Pat. No. 9,427,249, which is a divisional application claiming priority under 35 U.S.C. § 121 to U.S. patent application Ser. No. 12/703,875, filed Feb. 11, 2010, entitled ROTATABLE CUTTING IMPLEMENT ARRANGEMENTS FOR ULTRASONIC SURGICAL INSTRUMENTS, which issued on Jun. 25, 2013 as U.S. Pat. No. 8,469,981, the entire disclosures of which are hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     The present disclosure generally relates to ultrasonic surgical systems and, more particularly, to ultrasonic systems that allow surgeons to perform cutting and coagulation of tissue. 
     Over the years, a variety of different types of non-ultrasonically powered cutters and shaving devices for performing surgical procedures have been developed. Some of these devices employ a rotary cutting instrument and other devices employ a reciprocating cutting member. For example, shavers are widely used in arthroscopic surgery. These devices generally consist of a power supply, a handpiece, and a single-use end effector. The end effector commonly has an inner and outer tube. The inner tube rotates relative to the outer tube and will cut tissue with its sharpened edges. The inner tube can rotate continuously or oscillate. In addition, such device may employ a suction channel that travels through the interior of the inner tube. For example, U.S. Pat. No. 4,850,354 to McGurk-Burleson, et al., discloses a non-ultrasonically powered surgical cutting instrument that comprises a rotary cutter for cutting material with a shearing action. It employs an inner cutting member which is rotatable within an outer tube. 
     U.S. Pat. No. 3,776,238 to Peyman et al. discloses an ophthalmic instrument in which tissue is cut by a chopping action set-up by the sharp end of an inner tube moving against the inner surface of the end of an outer tube. U.S. Pat. No. 5,226,910 to Kajiyama et al. discloses another surgical cutting instrument that has an inner member which moves relative to an outer member to cut tissue entering through an aperture in the outer member. 
     U.S. Pat. No. 4,922,902 to Wuchinich et al. discloses a method and apparatus for endoscopic removal of tissue utilizing an ultrasonic aspirator. The device uses an ultrasonic probe which disintegrates compliant tissue and aspirates it through a narrow orifice. U.S. Pat. No. 4,634,420 to Spinosa et al. discloses an apparatus and method for removing tissue from an animal and includes an elongated instrument having a needle or probe, which is vibrated at an ultrasonic frequency in the lateral direction. The ultrasonic movement of the needle breaks-up the tissue into fragments. Pieces of tissue can be removed from the area of treatment by aspiration through a conduit in the needle. U.S. Pat. No. 3,805,787 to Banko discloses yet another ultrasonic instrument that has a probe that is shielded to narrow the beam of ultrasonic energy radiated from the tip of the probe. In one embodiment the shield extends past the free-end of the probe to prevent the probe from coming into contact with the tissue. U.S. Pat. No. 5,213,569 to Davis discloses a phaco-emulsification needle which focuses the ultrasonic energy. The focusing surfaces can be beveled, curved or faceted. U.S. Pat. No. 6,984,220 to Wuchinich and U.S. Patent Publication No. US 2005/0177184 to Easley disclose ultrasonic tissue dissection systems that provide combined longitudinal and torsional motion through the use of longitudinal-torsional resonators. U. S Patent Publication no. US 2006/0030797 A1 to Zhou et al. discloses an orthopedic surgical device that has a driving motor for driving an ultrasound transducer and horn. An adapter is provided between the driving motor and transducer for supplying ultrasonic energy signals to the transducer. 
     While the use of ultrasonically powered surgical instruments provide several advantages over traditional mechanically powered saws, drills, and other instruments, temperature rise in bone and adjacent tissue due to frictional heating at the bone/tissue interface can still be a significant problem. Current arthroscopic surgical tools include punches, reciprocating shavers and radio frequency (RF) devices. Mechanical devices such as punches and shavers create minimal tissue damage, but can sometimes leave behind ragged cut lines, which are undesirable. RF devices can create smoother cut lines and also ablate large volumes of soft tissue; however, they tend to create more tissue damage than mechanical means. Thus, device which could provide increased cutting precision while forming smooth cutting surfaces without creating excessive tissue damage would be desirable. 
     Arthroscopic surgery involves performing surgery in the joint space. To perform the surgery, the joints are commonly filled with pressurized saline for distention and visualization. Ultrasonic instruments which may be used in such surgeries must withstand the fluid pressure without leaking. However, conventional ultrasonic instruments generally experience significant forces during use. Current seals on ultrasonic devices are generally not robust enough to withstand this environment without leaking. 
     It would be desirable to provide an ultrasonic surgical instrument that overcomes some of the deficiencies of current instruments. The ultrasonic surgical instruments described herein overcome many of those deficiencies. 
     It would also be desirable to provide more robust sealing arrangements for ultrasonic surgical instruments used to cut and coagulate in the aqueous environment of arthroscopic surgery. 
     The foregoing discussion is intended only to illustrate some of the shortcomings present in the field of various embodiments of the invention at the time, and should not be taken as a disavowal of claim scope. 
     SUMMARY 
     In one exemplary embodiment, a surgical instrument may comprise a housing, a transducer assembly, a motor, a hollow sheath, and a blade. The transducer assembly may be rotatably supported within the housing and may be configured to selectively generate an ultrasonic motion. The motor may be coupled to the transducer assembly and may be configured to selectively apply rotational motion to the transducer assembly. The hollow sheath may be coupled to the housing and may define a distal cavity. The blade may be coupled to the transducer assembly and may be rotatably supported within the hollow sheath. A distal end of the blade may include a tissue-cutter that may be rotatably supported in the distal cavity. The distal cavity may comprise a friction reducing material. A portion of the tissue-cutter may be arranged to apply the ultrasonic motion to tissue. 
     In another exemplary embodiment, an ultrasonic surgical instrument may comprise a housing, an ultrasonic transducer assembly, a motor, an outer sheath, and a blade. The ultrasonic transducer assembly may selectively generate ultrasonic motion and may be rotatably supported within the housing. The motor may be within the housing may be configured to selectively apply a rotary motion to the ultrasonic transducer assembly. The outer sheath may be coupled to the housing. The outer sheath may comprise a distal tip portion that may define a tip cavity. The blade may be operably coupled to the ultrasonic transducer assembly and may be rotatably supported within the outer sheath for rotation with the ultrasonic transducer assembly. The blade may include a tissue-cutting distal end that may be rotatably supported within the tip cavity. The tip cavity may comprise a friction reducing material. A portion of the tissue-cutting distal end may be configured to apply the ultrasonic motion to tissue. 
     In yet another exemplary embodiment, a surgical instrument may comprise a housing, a rotatable transducer assembly, a motor, a cylindrical shaft, and a blade. The rotatable transducer assembly may be operable to selectively generate an ultrasonic motion. The motor may be operable to selectively rotate the rotatable transducer assembly within the housing. The cylindrical shaft may be coupled to the housing and may define a distal tip cavity. The blade may be operably coupled to the rotatable transducer assembly and may be rotatably supported within the cylindrical shaft. The blade may include a tissue-cutting distal end that may be rotatably supported within the distal tip cavity. The distal tip cavity may comprise a low friction material. The tissue-cutting distal end may be arranged to apply the ultrasonic motion to tissue. 
    
    
     
       FIGURES 
       The features of various non-limiting embodiments are set forth with particularity in the appended claims. The various non-limiting embodiments, 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 as follows. 
         FIG. 1  is a schematic view of a non-limiting embodiment of a surgical control system; 
         FIG. 1A  is a perspective view of a non-limiting embodiment of control system enclosure; 
         FIG. 1B  is a perspective view of another non-limiting embodiment of a control system enclosure arrangement; 
         FIG. 2  is a cross-sectional view of anon-limiting embodiment of a handpiece; 
         FIG. 3  is a partial cross-sectional view of an ultrasonic surgical handpiece that may be employed with various non-limiting embodiments; 
         FIG. 4  is a cross-sectional view of a portion of a non-limiting nosepiece embodiment; 
         FIG. 5  is a partial exploded assembly view of a non-limiting nosepiece embodiment; 
         FIG. 6  is a partial cross-sectional view of a non-limiting embodiment of a surgical instrument handpiece; 
         FIG. 7  is a perspective view of the non-limiting surgical instrument handpiece embodiment of  FIG. 6 ; 
         FIG. 8  is a partial cross-sectional view of another non-limiting surgical instrument handpiece embodiment; 
         FIG. 9  is a partial cross-sectional view of another non-limiting surgical instrument handpiece embodiment; 
         FIG. 10  is a perspective view of the surgical instrument handpiece embodiment depicted in  FIG. 9 ; 
         FIG. 11  is a partial exploded assembly view of a non-limiting coupling assembly embodiment for coupling a motor to a transducer assembly; 
         FIG. 12  is a side view of a thin plate member and drive shaft arrangement of a non-limiting coupling assembly embodiment; 
         FIG. 13  is an end view of the non-limiting thin plate member embodiment of  FIG. 12 ; 
         FIG. 14  is a side view of a non-limiting thin plate member and drive shaft arrangement of another non-limiting coupling assembly embodiment; 
         FIG. 15  is an end view of the non-limiting thin plate member embodiment of  FIG. 14 ; 
         FIG. 16  is a partial cross-sectional view of another non-limiting surgical instrument handpiece embodiment; 
         FIG. 17  is a partial perspective view of a non-limiting outer sheath and blade embodiment; 
         FIG. 18  is a partial perspective view of the non-limiting blade embodiment depicted in  FIG. 17 ; 
         FIG. 19  is a partial bottom perspective view of the blade of  FIGS. 17 and 18 ; 
         FIG. 20  is a side view of a portion of another non-limiting blade embodiment; 
         FIG. 21  is a side view of a portion of another non-limiting blade embodiment; 
         FIG. 22  is a partial perspective view of a distal end of another non-limiting outer sheath and blade arrangement; 
         FIG. 23  is a partial perspective view of a distal end of another non-limiting outer sheath and blade arrangement; 
         FIG. 23A  is a side view of a portion of the non-limiting outer sheath embodiment depicted in  FIG. 23 ; 
         FIG. 24  is a side view of a portion of another non-limiting blade embodiment; 
         FIG. 25  is a side view of a portion of another non-limiting blade embodiment; 
         FIG. 26  is a partial perspective view the non-limiting blade embodiment of  FIG. 25  within a distal end of another non-limiting outer sheath embodiment; 
         FIG. 27  is a side view of a portion of another non-limiting blade embodiment; 
         FIG. 28  is a partial perspective view the non-limiting blade embodiment of  FIG. 27  within a distal end of another non-limiting outer sheath embodiment; 
         FIG. 29  is a partial cross-sectional end view of the non-limiting blade and outer sheath embodiments of  FIG. 28 ; 
         FIG. 30  is a side view of a portion of another non-limiting blade embodiment; 
         FIG. 31  is a partial perspective view of the non-limiting blade embodiment of  FIG. 30  within a distal end of another non-limiting outer sheath embodiment; 
         FIG. 32A  illustrates a first rotational position of the non-limiting blade embodiment of  FIGS. 30 and 31  within the outer sheath embodiment of  FIG. 31 ; 
         FIG. 32B  illustrates a second rotational position of the non-limiting blade embodiment of  FIGS. 30 and 31  within the outer sheath embodiment of  FIG. 31 ; 
         FIG. 32C  illustrates a third rotational position of the blade embodiment of  FIGS. 30 and 31  within the outer sheath embodiment of  FIG. 31 ; 
         FIG. 32D  illustrates a fourth rotational position of the blade embodiment of  FIGS. 30 and 31  within the outer sheath embodiment of  FIG. 31 ; 
         FIG. 33  is a perspective view of a portion of another non-limiting blade embodiment; 
         FIG. 34  is a partial perspective view of the blade embodiment of  FIG. 33  within a non-limiting outer sheath embodiment; 
         FIG. 34A  is a partial perspective view of another non-limiting blade and outer sheath embodiment; 
         FIG. 35  is a perspective view of a portion of another non-limiting blade embodiment; 
         FIG. 36  is a partial cross-sectional view of another non-limiting ultrasonic surgical instrument embodiment; 
         FIG. 36A  is a partial cross-sectional view of a nosepiece portion of another non-limiting surgical instrument embodiment of the present invention; 
         FIG. 37  is a partial perspective view of a distal end of the non-limiting outer sheath and blade arrangement of  FIG. 36 ; 
         FIG. 38  is a cross-sectional view of distal portions of the outer sheath and blade embodiments depicted in  FIG. 37  cutting tissue; 
         FIG. 39  illustrates use of the surgical instrument embodiment of  FIG. 36  in connection with performing a discectomy; 
         FIG. 40  depicts further use of the surgical instrument embodiment of  FIG. 36  in connection with performing a discectomy; 
         FIG. 41  is a side elevational view of the surgical instrument embodiment of  FIG. 36  with a selectively retractable safety sheath mounted thereon; 
         FIG. 42  is a partial perspective view of the retractable safety sheath embodiment illustrated in  FIG. 41  starting to be retracted from a closed position; 
         FIG. 43  is another partial perspective view of the retractable safety sheath embodiment illustrated in  FIGS. 41 and 42  with the safety sheath retracted to an open position; 
         FIG. 44  is another partial perspective view of the retractable safety sheath embodiment illustrated in  FIGS. 41-43  with the safety sheath retracted to an open position; 
         FIG. 45  is a side elevational view of a portion of the outer sheath and safety sheath embodiments illustrated in  FIGS. 41-44  with the safety sheath shown in cross-section in an open position; 
         FIG. 46  is a perspective view of a portion of another non-limiting blade embodiment; 
         FIG. 47  is a side view of a portion of another hollow outer sheath and blade arrangement of another non-limiting embodiment; 
         FIG. 48  is a cross-sectional view of another non-limiting blade embodiment; 
         FIG. 49  is a cross-sectional view of another non-limiting blade embodiment; 
         FIG. 50  is a cross-sectional view of another non-limiting blade embodiment; 
         FIG. 51  is a cross-sectional view of another non-limiting blade embodiment; 
         FIG. 52  is a partial cross-sectional view of another non-limiting outer sheath and blade embodiment; 
         FIG. 53  is another partial cross-sectional view of the outer sheath and blade embodiment of  FIG. 52  interacting with body tissue; 
         FIG. 54  is an end cross-sectional view of the outer sheath and blade arrangement depicted in  FIGS. 52 and 53  interacting with body tissue; 
         FIG. 55  is a partial perspective view of another non-limiting outer sheath embodiment; 
         FIG. 56  is a partial perspective view of another non-limiting outer sheath embodiment; 
         FIG. 57  is a partial cross-sectional view of the outer sheath embodiment of  FIG. 56  supporting another non-limiting blade embodiment; 
         FIG. 58  is a partial perspective view of another non-limiting outer sheath embodiment; 
         FIG. 59  is a cross-sectional view of another non-limiting outer sheath and blade embodiment; 
         FIG. 60  illustrates an angle between the cutting edges formed on a non-limiting outer sheath embodiment; 
         FIG. 61  is a perspective view of another non-limiting outer sheath embodiment; 
         FIG. 62  is a cross-sectional view of the outer sheath and blade embodiment of  FIG. 61 ; 
         FIG. 63  is a perspective view of another non-limiting outer sheath embodiment; 
         FIG. 64  is a cross-sectional view of the outer sheath and blade embodiment of  FIG. 63 ; 
         FIG. 65  is a perspective view of another non-limiting outer sheath embodiment; 
         FIG. 66  is a cross-sectional view of the outer sheath and blade embodiment of  FIG. 65 ; 
         FIG. 67  is a cross-sectional end view of another non-limiting outer sheath and blade arrangement; 
         FIG. 68  is a partial side cross-sectional view of the outer sheath and blade arrangement of  FIG. 67 ; 
         FIG. 69  is a partial side view of a distal end portion of the outer sheath and blade arrangement of  FIGS. 67 and 68 ; 
         FIG. 70  is a side view of a non-limiting handpiece housing embodiment attached to the outer sheath and blade arrangement of  FIGS. 67-69 ; 
         FIG. 71  depicts a method of using the surgical instrument embodiment of  FIG. 70 ; 
         FIG. 72  depicts another method of using the surgical instrument embodiment of  FIG. 70 ; 
         FIG. 73  depicts another method of using the surgical instrument embodiment of  FIG. 70 ; 
         FIG. 74  is a partial side cross-sectional view of another non-limiting surgical instrument embodiment; 
         FIG. 75  is a perspective view of a portion of the outer sheath and blade arrangement employed with the surgical instrument embodiment depicted in  FIG. 74 ; 
         FIG. 76  is an end view of the outer sheath and blade arrangement of  FIG. 75 ; 
         FIG. 77  is a cross-sectional end view of the sheath and blade arrangement of  FIGS. 75 and 76 ; 
         FIG. 78  is a side view of another non-limiting ultrasonic surgical instrument embodiment; 
         FIG. 79  is a partial cross-sectional view of a non-limiting seal embodiment between a hollow sheath and a waveguide portion of an ultrasonic implement embodiment; 
         FIG. 80  is a partial cross-sectional view of another non-limiting seal embodiment between a hollow sheath and a waveguide portion of an ultrasonic implement embodiment; 
         FIG. 81  is a partial cross-sectional view of another non-limiting seal embodiment between a hollow sheath and a waveguide portion of an ultrasonic implement embodiment; 
         FIG. 82  is a partial cross-sectional view of another non-limiting seal embodiment between a hollow sheath and a waveguide portion of an ultrasonic implement embodiment; 
         FIG. 83  is a partial cross-sectional view of another non-limiting seal embodiment between a hollow sheath and a waveguide portion of an ultrasonic implement embodiment, prior to being crimped in position; 
         FIG. 84  is a partial cross-sectional view of the seal embodiment of  FIG. 83  after being crimped in position; 
         FIG. 85  is a partial cross-sectional view of another non-limiting seal embodiment between a two-piece hollow sheath and a waveguide portion of an ultrasonic implement embodiment; 
         FIG. 86  is a partial cross-sectional exploded assembly view of another non-limiting seal embodiment between another two-piece hollow sheath and a waveguide portion of an ultrasonic implement embodiment; 
         FIG. 87  is a partial perspective view of a portion of the two piece hollow sheath embodiment of  FIG. 86 ; 
         FIG. 88  is a partial cross-sectional view of another non-limiting seal embodiment between a hollow sheath and a waveguide portion of an ultrasonic implement embodiment; 
         FIG. 89  is a partial cross-sectional view of another non-limiting seal embodiment between a hollow sheath and a waveguide portion of an ultrasonic implement embodiment; 
         FIG. 90  is a partial cross-sectional view of another non-limiting seal embodiment between a hollow sheath and a waveguide portion of an ultrasonic implement embodiment; 
         FIG. 91A  is an illustration depicting an initial position of two cutting edge embodiments preparing to cut tough tissue; 
         FIG. 91B  is a second position of the cutting edges and tissue of  FIG. 91A ; 
         FIG. 91C  is a third position of the cutting edges and tissue of  FIGS. 91A-B ; 
         FIG. 91D  is a fourth position of the cutting edges and tissue of  FIGS. 91A-C ; 
         FIG. 92  is a perspective view of a portion of a non-limiting cutting blade and bushing embodiment; 
         FIG. 92A  is a partial cross-sectional view of a portion of the blade and bushing embodiment of  FIG. 92  installed within an inner sheath of a non-limiting surgical instrument embodiment; 
         FIG. 93  is a cross-sectional view of a portion of the blade and bushing embodiment of  FIG. 92  in a non-limiting surgical instrument embodiment; 
         FIG. 94  is a perspective view of a portion of another non-limiting cutting blade and bushing embodiment; 
         FIG. 95  is a cross-sectional view of a portion of the blade and bushing embodiment of  FIG. 94  in a non-limiting surgical instrument embodiment; 
         FIG. 96  is a partial perspective view of a portion of a non-limiting blade and outer sheath embodiment; 
         FIG. 97  is a cross-sectional view of the blade and outer sheath arrangement of  FIG. 96 ; 
         FIG. 98  is a partial rear perspective view of a portion of the outer sheath and blade arrangement of  FIG. 97 ; 
         FIG. 99  is a partial rear perspective view of a portion of another non-limiting outer sheath and blade embodiment; 
         FIG. 100  is a partial perspective view of another non-limiting outer sheath embodiment; 
         FIG. 101  is a cross-sectional end view of the outer sheath embodiment of  FIG. 100  supporting a cutting blade embodiment therein; and 
         FIG. 102  is a perspective view of a portion of another non-limiting blade embodiment. 
     
    
    
     DESCRIPTION 
     The owner of the present application also owns the following U.S. Patent Applications, filed Feb. 11, 2010, which are herein incorporated by reference in their respective entireties: 
     U.S. patent application Ser. No. 12/703,860, now U.S. Pat. No. 8,531,064, entitled ULTRASONICALLY POWERED SURGICAL INSTRUMENTS WITH ROTATING CUTTING IMPLEMENT; 
     U.S. patent application Ser. No. 12/703,864, now U.S. Pat. No. 8,323,302, entitled METHODS OF USING ULTRASONICALLY POWERED SURGICAL INSTRUMENTS WITH ROTATABLE CUTTING IMPLEMENTS; 
     U.S. patent application Ser. No. 12/703,866, now U.S. Pat. No. 8,951,272, entitled SEAL ARRANGEMENTS FOR ULTRASONICALLY POWERED SURGICAL INSTRUMENTS; 
     U.S. patent application Ser. No. 12/703,870, now U.S. Pat. No. 9,259,234, entitled ULTRASONIC SURGICAL INSTRUMENTS WITH ROTATABLE BLADE AND HOLLOW SHEATH ARRANGEMENTS; 
     U.S. patent application Ser. No. 12/703,877, now U.S. Pat. No. 8,382,782, entitled ULTRASONIC SURGICAL INSTRUMENTS WITH PARTIALLY ROTATING BLADE AND FIXED PAD ARRANGEMENT; 
     U.S. patent application Ser. No. 12/703,879, now U.S. Pat. No. 8,486,096, entitled DUAL PURPOSE SURGICAL INSTRUMENT FOR CUTTING AND COAGULATING TIS SUE; 
     U.S. patent application Ser. No. 12/703,885, now U.S. Pat. No. 8,579,928, entitled OUTER SHEATH AND BLADE ARRANGEMENTS FOR ULTRASONIC SURGICAL INSTRUMENTS; 
     U.S. patent application Ser. No. 12/703,893, now U.S. Pat. No. 8,961,547, entitled ULTRASONIC SURGICAL INSTRUMENTS WITH MOVING CUTTING IMPLEMENT; and 
     U.S. patent application Ser. No. 12/703,899, now U.S. Pat. No. 8,419,759, entitled ULTRASONIC SURGICAL INSTRUMENT WITH COMB-LIKE TISSUE TRIMMING DEVICE. 
     Various embodiments are directed to apparatuses, systems, and methods for the treatment of tissue Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. It will be understood by those skilled in the art, however, that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Those of ordinary skill in the art will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments, the scope of which is defined solely by the appended claims. 
     Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment”, or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment”, or the like, in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features structures, or characteristics of one or more other embodiments without limitation. 
     Various embodiments are directed to improved ultrasonic surgical systems and instruments configured for effecting tissue dissecting, cutting, and/or coagulation during surgical procedures as well as the cutting implements and sealing features employed thereby. In one embodiment, an ultrasonic surgical instrument apparatus is configured for use in open surgical procedures, but has applications in other types of surgery, such as laparoscopic, endoscopic, and robotic-assisted procedures. Versatile use is facilitated by selective use of ultrasonic energy and the selective rotation of the cutting/coagulation implement. 
     It will be appreciated that the terms “proximal” and “distal” are used herein with reference to a clinician gripping a handpiece assembly. Thus, an end effector is distal with respect to the more proximal handpiece assembly. It will be further appreciated that, for convenience and clarity, spatial terms such as “top” and “bottom” also are used herein with respect to the clinician gripping the handpiece assembly. However, surgical instruments are used in many orientations and positions, and these terms are not intended to be limiting and absolute. 
     Surgical Systems 
       FIG. 1  illustrates in schematic form one non-limiting embodiment of a surgical system  10 . The surgical system  10  may include a ultrasonic generator  12  and an ultrasonic surgical instrument assembly  100  that may include a “self-contained” ultrasonic instrument  110 . As will be discussed in further detail below, the ultrasonic generator  12  may be connected by a cable  14  to an ultrasonic transducer assembly  114  of the self-contained ultrasonic instrument  110  by a slip ring assembly  150  located in a housing portion  102  of the surgical instrument assembly  100 . In one embodiment, the system  10  further includes a motor control system  20  that includes a power supply  22  that is coupled to a control module  24  by cable  23  to supply, for example, 24 VDC thereto. The motor control module  24  may comprise a control module manufactured by National Instruments of Austin, Tex. under Model No. NI cRIO-9073. However, other motor control modules may be employed. The power supply  22  may comprise a power supply manufactured by National Instruments. However, other power supplies may be successfully employed. The power supply  22  may be further coupled to a motor drive  26  by cable  25  to also supply 24 VDC thereto. The motor drive  26  may comprise a motor drive manufactured by National Instruments. Control module  24  may also be coupled to the motor drive  26  by cable  27  for supplying power thereto. A conventional foot pedal  30  or other control switch arrangement may be attached to the control module  24  by a cable  31 . As will be discussed in further detail below, the ultrasonic surgical instrument  100  may include a motor  190  that has an encoder  194  associated therewith. The motor  190  may comprise a motor manufactured by National Instruments under Model No. CTP12ELF10MAA00. The encoder  194  may comprise an encoder manufactured by U.S. Digital of Vancouver, Wash. under Model No. E2-500-197-I-D-D-B. However, other motors and encoders may be used. The encoder  194  may be coupled to the motor control module  24  by an encoder cable  32  and the motor  190  may be coupled to the motor drive  26  by cable  33 . The surgical system  10  may also include a computer  40  that may communicate by Ethernet cable  42  with the motor control module  24 . 
     As can also be seen in  FIG. 1 , in various embodiments, the motor control system  20  is housed in an enclosure  21 . To facilitate easy portability of the system, various components may be attached to the motor control system  20  by removable cable connectors. For example, foot pedal switch  30  may be attached to a detachable cable connector  37  by cable  35  to facilitate quick attachment of the foot pedal to the control system  20 . A/C power may be supplied to the power supply  22  by a conventional plug/cable  50  that is attached to a detachable cable connector  54  that is attached to cable  52 . The computer  40  may have a cable  60  that is attached to detachable cable connector  62  that is coupled to cable  42 . The encoder  194  may have an encoder cable  70  that is attached to a detachable connector  72 . Likewise, the motor  190  may have a cable  74  that is attached to the detachable connector  72 . The detachable connector  72  may be attached to the control module  24  by cable  32  and the connector  72  may be attached to the motor drive  26  by cable  33 . Thus, cable connector  72  serves to couple the encoder  194  to the control module  24  and the motor  190  to the motor drive  26 . The cables  70  and  74  may be housed in a common sheath  76 . 
     In an alternative embodiment, the ultrasonic generator  12  and the control system  20  may be housed in the same enclosure  105 . See  FIG. 1A . In yet another embodiment, the ultrasonic generator  12  may electrically communicate with the motor control system  20  by a jumper cable  107 . Such arrangement may share a data link as well as a common means for supplying power (cord  50 ). See  FIG. 1B . 
     In various embodiments, the ultrasonic generator  12  may include an ultrasonic generator module  13  and a signal generator module  15 . See  FIG. 1 . The ultrasonic generator module  13  and/or the signal generator module  15  each may be integrated with the ultrasonic generator  12  or may be provided as a separate circuit module electrically coupled to the ultrasonic generator  12  (shown in phantom to illustrate this option). In one embodiment, the signal generator module  15  may be formed integrally with the ultrasonic generator module  13 . The ultrasonic generator  12  may comprise an input device  17  located on a front panel of the generator  12  console. The input device  17  may comprise any suitable device that generates signals suitable for programming the operation of the generator  12  in a known manner. Still with reference to  FIG. 1 , the cable  14  may comprise multiple electrical conductors for the application of electrical energy to positive (+) and negative (−) electrodes of an ultrasonic transducer assembly  114  as will be discussed in further detail below. 
     Various forms of ultrasonic generators, ultrasonic generator modules and signal generator modules are known. For example, such devices are disclosed in commonly owned U.S. patent application Ser. No. 12/503,770, entitled Rotating Transducer Mount For Ultrasonic Surgical Instruments, filed Jul. 15, 2007, now U.S. Pat. No. 8,461,744, which is herein incorporated by reference in its entirety. Other such devices are disclosed in one or more of the following U.S. Patents, all of which are incorporated by reference herein: U.S. Pat. No. 6,480,796 (Method for Improving the Start Up of an Ultrasonic System Under Zero Load Conditions); U.S. Pat. No. 6,537,291 (Method for Detecting a Loose Blade in a Handle Connected to an Ultrasonic Surgical System); U.S. Pat. No. 6,626,926 (Method for Driving an Ultrasonic System to Improve Acquisition of Blade Resonance Frequency at Startup); U.S. Pat. No. 6,633,234 (Method for Detecting Blade Breakage Using Rate and/or Impedance Information); U.S. Pat. No. 6,662,127 (Method for Detecting Presence of a Blade in an Ultrasonic System); U.S. Pat. No. 6,678,621 (Output Displacement Control Using Phase Margin in an Ultrasonic Surgical Handle); U.S. Pat. No. 6,679,899 (Method for Detecting Transverse Vibrations in an Ultrasonic Handle); U.S. Pat. No. 6,908,472 (Apparatus and Method for Altering Generator Functions in an Ultrasonic Surgical System); U.S. Pat. No. 6,977,495 (Detection Circuitry for Surgical Handpiece System); U.S. Pat. No. 7,077,853 (Method for Calculating Transducer Capacitance to Determine Transducer Temperature); U.S. Pat. No. 7,179,271 (Method for Driving an Ultrasonic System to Improve Acquisition of Blade Resonance Frequency at Startup); and U.S. Pat. No. 7,273,483 (Apparatus and Method for Alerting Generator Function in an Ultrasonic Surgical System). 
     Surgical Instruments 
     As can be seen in  FIG. 2 , an ultrasonic surgical instrument handpiece  100  may comprise a housing  102  that houses the motor  190 , the encoder  194 , the slip ring assembly  150  and the self-contained ultrasonic surgical instrument  110 . The housing  102  may be provided in two or more parts that are attached together by fasteners such as screws, snap features, etc. and may be fabricated from, for example, polycarbonate material. The motor  190  may comprise, for example, a stepper motor manufactured by National Instruments under Model No. CTP12ELF10MAA00. However other motors may be employed to effectuate, for example, “gross” rotational motion of the self-contained ultrasonic surgical instrument  110  relative to the housing  102  on the order of 1-6000 rpm. The encoder  194  converts the mechanical rotation of the motor shaft  192  into electrical pulses that provide speed and other motor control information to the control module  24 . 
     The self-contained ultrasonic surgical instrument  110  may comprise a surgical instrument that is manufactured and sold by Ethicon Endo-Surgery under Model No. HP054. However, other ultrasonic instruments may be successfully employed. It will be understood that the term “self-contained” as used herein means that the ultrasonic surgical instrument may be effectively used as an ultrasonic surgical instrument on its own, apart from use with the surgical instrument  100 . As illustrated in more detail in  FIG. 3 , the ultrasonic surgical instrument  110  includes a housing  112  that supports a piezoelectric ultrasonic transducer assembly  114  for converting electrical energy to mechanical energy that results in longitudinal vibrational motion of the ends of the transducer assembly  114 . The ultrasonic transducer assembly  114  may comprise a stack of ceramic piezoelectric elements with a motion null point located at some point along the stack. The ultrasonic transducer assembly  114  may be mounted between two cylinders  116  and  118 . In addition, a cylinder  120  may be attached to cylinder  118 , which in turn is mounted to the housing at another motion null point  122 . A horn  124  may also be attached at the null point on one side and to a coupler  126  on the other side. A blade  200  may be fixed to the coupler  126 . As a result, the blade  200  will vibrate in the longitudinal direction at an ultrasonic frequency rate with the ultrasonic transducer assembly  114 . The ends of the ultrasonic transducer assembly  114  achieve maximum motion with a portion of the stack constituting a motionless node, when the ultrasonic transducer assembly  114  is driven at maximum current at the transducer&#39;s resonant frequency. However, the current providing the maximum motion will vary with each instrument and is a value stored in the non-volatile memory of the instrument so the system can use it. 
     The parts of the ultrasonic instrument  110  may be designed such that the combination will oscillate at the same resonant frequency. In particular, the elements may be tuned such that the resulting length of each such element is one-half wavelength or a multiple thereof. Longitudinal back and forth motion is amplified as the diameter closer to the blade  200  of the acoustical mounting horn  124  decreases. Thus, the horn  124  as well as the blade/coupler may be shaped and dimensioned so as to amplify blade motion and provide ultrasonic vibration in resonance with the rest of the acoustic system, which produces the maximum back and forth motion of the end of the acoustical mounting horn  124  close to the blade  200 . A motion from 20 to 25 microns at the ultrasonic transducer assembly  114  may be amplified by the horn  124  into blade movement of about 40 to 100 microns. 
     When power is applied to the ultrasonic instrument  110  by operation of the foot pedal  30  or other switch arrangement, the control system  20  may, for example, cause the blade  200  to vibrate longitudinally at approximately 55.5 kHz, and the amount of longitudinal movement will vary proportionately with the amount of driving power (current) applied, as adjustably selected by the user. When relatively high cutting power is applied, the blade  200  may be designed to move longitudinally in the range of about 40 to 100 microns at the ultrasonic vibrational rate. Such ultrasonic vibration of the blade  200  will generate heat as the blade contacts tissue, i.e., the acceleration of the blade  200  through the tissue converts the mechanical energy of the moving blade  200  to thermal energy in a very narrow and localized area. This localized heat creates a narrow zone of coagulation, which will reduce or eliminate bleeding in small vessels, such as those less than one millimeter in diameter. The cutting efficiency of the blade  200 , as well as the degree of hemostasis, will vary with the level of driving power applied, the cutting rate or force applied by the surgeon to the blade, the nature of the tissue type and the vascularity of the tissue. 
     As can be seen in  FIG. 2 , the ultrasonic instrument  110  is supported within the housing  102  by a tailpiece drive adapter  130  and a distal handpiece adapter  134 . The tailpiece drive adapter  130  is rotatably supported within housing  102  by a proximal bearing  132  and is non-rotatably coupled to the output shaft  192  of the motor  190 . See  FIG. 2 . The tailpiece drive adapter  130  may be pressed onto the housing  112  of the ultrasonic instrument  110  or, for example, be attached to the housing  112  by setscrews or adhesive. The distal handpiece adapter  134  may be pressed onto a distal end  113  of the handpiece housing  112  or be otherwise attached thereto by set screws or adhesive. The distal handpiece adapter  134  is rotatably supported in the housing  102  by a distal bearing  136  that is mounted within housing  102 . 
     When power is applied to motor  190 , motor  190  applies a “gross rotational motion” to the handpiece  110  to cause the ultrasonic surgical instrument  110  and blade  200  to rotate about central axis A-A. As used herein, the term “gross rotational motion” is to be distinguished from that “torsional ultrasonic motion” that may be achieved when employing a non-homogeneous formed ultrasonic blade. The term “gross rotational motion” instead encompasses rotational motion that is not solely generated by operation of the ultrasonic transducer assembly  114 . 
     To provide the ultrasonic instrument  110  with power from the ultrasonic generator  12 , a slip ring assembly  150  may be employed. As can be seen in  FIG. 2 , conductors  151 ,  152  are coupled to the ultrasonic transducer assembly  114  and extend through a hollow stem portion  132  of the tail piece drive adapter  130 . The hollow stem portion  132  is attached to the drive shaft  192  of the motor  190  and is free to rotate within the slip ring assembly  150 . A first inner contact  154  is attached to the hollow stem portion  132  for rotational travel therewith about axis A-A. The first inner contact  154  is positioned for rotational contact with a fixed outer contact  156  within the slip ring assembly  150 . The contacts  154 ,  156  may be provided in the form of concentrically arranged rings. Conductors  157 ,  158  are coupled to the fixed outer contact  156  and form generator cable  14 . Conductors  191  and  193  are attached to the motor and form motor cable  74  and conductors  195 ,  197  are attached to encoder  194  and form encoder cable  70 . Rotation of the motor shaft  192  results in the rotation of the tailpiece drive adapter  130  and the ultrasonic instrument  110  attached thereto about axis A-A. Rotation of the motor drive shaft  192  also results in the rotation of the inner contact  154 . Ultrasonic signals from the ultrasonic generator  12  are transferred to the inner contact  154  by virtue of contact or “electrical communication” between the inner contact  154  and the outer contact  156 . Those signals are transmitted to the ultrasonic transducer assembly  114  by conductors  151 ,  152 . In other alternative embodiments, the slip ring assembly may employ use of conventional pogo pins that engage concentric ring contacts. Other slip ring arrangements could also be employed. 
     Various embodiments also include a distal nosepiece  160  that may be removably attached to the distal end  103  of the housing  102  by fasteners  161 . See  FIG. 5 . One or more shim members  162  may be positioned between the distal end  103  and the nosepiece  160  to facilitate coaxial attachment between the housing  102  and the nosepiece  160 . The nosepiece  160  may be fabricated from, for example, stainless steel or polycarbonate. In various embodiments, the distal end  202  of the blade  200  extends through a hollow coupler segment  210  that is journaled within an inner sheath seal  212 . Inner sheath seal  212  may comprise, for example, polytetrafluoroethylene (PTFE″), and serve to establish a substantially fluid-tight and/or airtight seal between the coupler segment  210  and the nosepiece  160 . Also in the embodiment of  FIG. 4 , an inner sheath  220  may be attached to the hollow coupler segment  210  by, for example, welding or the hollow coupler segment  210  may comprise an integral portion of the inner sheath  220 . In one embodiment, a blade pin/torquing member  216  may extend transversely through the blade member  200  and the hollow coupler segment  210  to facilitate movement of the inner sheath  220  with the blade member  200 . One or more vented silicone bushings  214  may be journaled around the blade  200  to acoustically isolate the blade  200  from the inner sheath  220 . The blade member  200  may have a proximal end  201  that is internally threaded and adapted to removably engage a threaded portion of the coupler  126 . To facilitate tightening of the blade  200  to the coupler  126 , a tightening hole  108  ( FIG. 2 ) may be provided through the housing  102  to enable a tool (e.g., Allen wrench) to be inserted therethrough into a hole  131  in the tail piece drive adapter  130  to prevent the rotation of the ultrasonic surgical instrument  110  and coupler  126  attached thereto. Once the blade  200  has been screwed onto the coupler  126 , the user may remove the Allen wrench or other tool from holes  108 ,  131  and insert a threaded plug (not shown) into hole  108  to prevent fluids/debris from entering the housing  102  therethrough. 
     Also in various embodiments, an outer sheath  230  may be coaxially aligned with the inner sheath  220  and blade member  200  and be attached to a distal end  163  of nosepiece  160  by, for example, welding, brazing, overmolding or pressfit. As can be seen in  FIG. 4 , a suction port  240  may be attached to the nosepiece  160  to communicate with the hollow outer sheath  230 . A flexible tube  242  may be attached to the suction port  240  and communicate with a collection receptacle  243  that is coupled to a source of vacuum, generally depicted as  244 . Thus, the outer sheath  230  forms a suction path extending around the inner sheath  220  that begins at a distal tip of the outer sheath  230  and goes out through the suction port  240 . Those of ordinary skill in the art will appreciate that alternate suction paths are also possible. In addition, in alternative embodiments, the inner sheath  220  is omitted. 
     Various embodiments of the surgical system  10  provide the ability to selectively apply ultrasonic axial motion to the blade  200  and gross rotational motion to the blade  200  as well. If desired, the clinician may simply activate the ultrasonic transducer assembly  114  without activating the motor  190 . In such cases, the instrument  100  may be used in ultrasonic mode simply as an ultrasonic instrument. Frequency ranges for longitudinal ultrasonic motion may be on the order of, for example, 30-80 kHz. Similarly, the clinician may desire to active the motor  190  without activating the ultrasonic transducer assembly  114 . Thus, gross rotational motion will be applied to the blade  200  in the rotation mode, without the application of longitudinal ultrasonic motion thereto. Gross rotational speeds may be, for example, on the order of 1-6000 rpm. In other applications, the clinician may desire to use the instrument  100  in the ultrasonics and rotational modes wherein the blade  200  will experience longitudinal ultrasonic motion from the transducer assembly  114  and gross rotational motion from the motor. Oscillatory motion of, for example, 2 to 10 revolutions per cycle (720 to 3600 degrees) or continuous unidirectional rotation may be achieved. Those of ordinary skill in the art will readily appreciate that various embodiments of the surgical system  10  may be affectively employed in connection with arthroscopic as well as other surgical applications. 
     At least one non-limiting embodiment may further include a control arrangement  170  on the housing  102 . See  FIG. 2 . The control arrangement  170  may communicate with the control module  24  by multi-conductor cable  171 . The control arrangement  170  may include a first button  172  for activating/deactivating a “dual” mode that includes the “ultrasonic mode” and “rotational mode”. In such arrangements, the control module  24  may be pre-programmed to provide a pre-set amount of gross rotational motion to the blade  200 . The control arrangement  170  may further include a second button  174  for activating/deactivating the rotational mode without activating the ultrasonics mode to thereby cut without hemostasis. The control arrangement  170  may also include a third button  176  for activating/deactivating a “coagulation mode” wherein the motor  190  drives to a pre-set rotational orientation and then “parks” or deactivates, thereby exposing the ultrasonic blade surface at the distal end of the outer sheath  240  as will be discussed in further detail below. Also in this mode, the ultrasonic transducer assembly  114  may be powered to provide spot coagulation or in an alternative embodiment, the clinician may simply activate a spot coagulation button  77  which activates the ultrasonic transducer assembly  114  for a preset time period of, for example, five seconds. The control arrangement may further include a button  178  to switch between ultrasonics and rotational modes. In accordance with various non-limiting embodiments, any combinations of the aforementioned functions/modes may be combined and controlled by one or more buttons without departing from the spirit and scope of the various non-limiting embodiments disclosed herein as well as their equivalent structures. 
     Those of ordinary skill in the art will understand that the housing member  102  and the mounting adapters  130  and  134  may be configured to operably support various different types and shapes of ultrasonic handpieces therein that may be independently used apart from the surgical instrument  100 . Thus, the control system  20  and instrument  100  may be provided in “kit form” without the ultrasonic handpiece  110  to enable the purchaser to install their existing ultrasonic handpiece therein without departing from the spirit and scope of the various non-limiting embodiments disclosed herein as well as their respective equivalent structures. 
       FIGS. 6 and 7  illustrate another surgical instrument  300  wherein like numbers previously used to describe the various embodiments discussed above are used to designate like components. In these embodiments, the surgical instrument  300  includes a housing  302  that houses a transducer assembly  314  that is attached to an ultrasonic horn  324 . The ultrasonic horn  324  may be coupled to the proximal end  201  of the blade  200  in the manner described above. The ultrasonic horn  324  may be rotatably supported within the housing  302  by a distal bearing  336 . A nosepiece  160  may be attached to the housing  302  by fasteners  161  in the manner described above. 
     In this embodiment, the ultrasonic transducer assembly  314  has magnets  316  embedded or otherwise attached thereto to form an integral motor rotor, generally designated as  320 . A motor stator ring  330  is mounted within the housing  302  as shown. Conductors  332 ,  334  are attached to the motor stator ring  330  and pass through the common sheath  76  to be attached to the motor cable  33  in the control system  20  as described above. A hollow shaft  340  extends through the motor rotor  320  to form a passage for conductors  151 ,  152 . Conductors  151 ,  152  are coupled to the ultrasonic transducer assembly  314  and an inner contact  154 . The inner contact  154  is attached to a portion of the hollow shaft  340  that rotatably extends into a slip ring assembly  150  that is also supported within the housing  302 . The hollow shaft  340  is rotatably supported within the housing  302  by a proximal bearing  342 . The slip ring assembly  150  is fixed (i.e., non-rotatable) within the housing  302  and includes a fixed outer contact  156  that is coupled to conductors  157 ,  158  that form generator cable  14  as was described above. When power is supplied to the motor stator  330 , the rotor  320  and the integral ultrasonic transducer  314  are caused to rotate about axis A-A. Ultrasonic signals from the ultrasonic generator  12  are transferred to the inner contact  154  by virtue of rotating contact or electrical communication between the inner contact  154  and the outer contact  156 . Those signals are transmitted to the ultrasonic transducer assembly  314  by conductors  151 ,  152 . The surgical instrument  300  may include a control arrangement of the type described above and be used in the various modes described above. A suction may be applied between the blade  200  and outer sheath  230  through port  240 . A collection receptacle  243  and source of suction  240  may be attached to the port  240  by tube  242 . The distal end of the blade is exposed through a window in the distal end of the outer sheath  230  to expose the blade to tissue as will be further discussed below. 
       FIG. 8  illustrates another surgical instrument  400  wherein like numbers previously used to describe the various embodiments discussed above are used to designate like components. In these embodiments, the surgical instrument  400  includes a housing  302  that houses an ultrasonic transducer assembly  314  that is attached to an ultrasonic horn  324 . The ultrasonic horn  324  may be coupled to the proximal end  201  of the blade  200  in the manner described above. The ultrasonic horn  324  may be rotatably supported within the housing  302  by a distal bearing  336 . A nosepiece  160  may be attached to the housing  302  in the manner described above. 
     In this embodiment, a brushed motor  410  is integrally attached to the ultrasonic transducer assembly  314 . As used herein “integrally attached” means directly attached to or otherwise formed with the ultrasonic transducer assembly  314  for travel therewith. The term “integrally attached” as used with reference to the attachment of the brushed motor  410  to the ultrasonic transducer assembly  314  does not encompass those configurations wherein the ultrasonic transducer assembly is attached to the motor via a driven shaft arrangement. Also in this embodiment, magnets  426  are provided in a stator ring  420  that is fixed within the housing  302 . Conductors  432 ,  434  extend through a hollow shaft  340  that is attached to the brushed motor  410 . The hollow shaft  340  is rotatably supported within the housing  302  by proximal bearing  342 . The motor conductor  432  is attached to a first inner motor contact  436  and the motor conductor  434  is attached to a second inner motor contact  438 . The first and second inner motor contacts  436 ,  438  are supported on the portion of the hollow shaft  340  that extends into a slip ring assembly, generally designated as  450 . The slip ring assembly  450  is fixed (i.e., non-rotatable) within the housing  302  and includes a first outer motor contact  440  that is coupled to conductor  441  and a second outer motor contact  442  that is coupled to conductor  443 . The conductors  441 ,  443  form motor cable  74  as was described above. When the clinician desires to apply gross rotational motion to the ultrasonic transducer assembly  314  and ultimately to the blade  200 , the clinician causes power to be supplied to the brushed motor  410  from the motor drive  26 . 
     Also in this embodiment, conductors  151 ,  152  are attached to the ultrasonic transducer assembly  314  and extend through the hollow shaft  340  to be coupled to inner transducer contact  154  that is attached to the hollow shaft  340 . The slip ring assembly  450  includes a fixed outer transducer contact  156  that is coupled to conductors  157 ,  158  that form generator cable  14  as was described above. When power is supplied to the brushed motor  410 , the motor  410 , ultrasonic transducer assembly  314 , and motor shaft  340  are caused to rotate about axis A-A. Ultrasonic signals from the ultrasonic generator  12  are transferred to the inner contact  154  by virtue of rotational sliding contact or electrical communication between the inner contact  154  and the outer contact  156 . Those signals are transmitted to the ultrasonic transducer assembly  314  by conductors  151 ,  152 . The surgical instrument  400  may include a control arrangement of the type described above and be used in the various modes described above. It will be understood that the instrument  400  may be used in rotation mode, ultrasonic mode, rotation and ultrasonic mode (“duel mode”) or coagulation mode as described above. A suction may be applied between the blade  200  and outer sheath  230  through port  240 . A collection receptacle  243  and source of suction  240  may be attached to the port  240  by tube  242 . The distal end of the blade is exposed through a window in the distal end of the outer sheath  230  to expose the blade to tissue as will be further discussed below. 
       FIGS. 9-13  illustrate another surgical instrument  500  wherein like numbers previously used to describe the various embodiments discussed above are used to designate like components. In these embodiments, the surgical instrument  500  includes a housing  302  that houses a transducer assembly  530  that is attached to an ultrasonic horn  324 . The ultrasonic horn  324  may be coupled to the proximal end  201  of the blade  200  in the manner described above. The ultrasonic horn  324  may be rotatably supported within the housing  302  by a distal bearing  336 . A nosepiece  160  may be attached to the housing  302  in the manner described above. 
     This embodiment includes a motor  510  that may comprise a stepper motor of the type and construction described above and may have an encoder portion associated therewith that communicates with the control module  24  as was described above. The motor  510  may receive power from the motor drive  26  through conductors  511 ,  512  that comprise motor cable  74  that extends through the common sheath  76 . The motor  510  has a hollow motor shaft  520  attached thereto that extends through a slip ring assembly  150 . The hollow drive shaft  520  is rotatably supported within the housing  302  by a proximal bearing  342 . The slip ring assembly  150  is fixed (i.e., non-rotatable) within the housing  302  and includes a fixed outer contact  156  that is coupled to conductors  157 ,  158  that form generator cable  14  as was described above. An inner contact  154  is mounted on the hollow drive shaft  520  and is in electrical contact or communication with outer contact  156 . Conductors  151 ,  152  are attached to the inner contact  154  and extend through the hollow drive shaft  520  to be coupled to the ultrasonic transducer assembly  530 . 
     In various embodiments, to facilitate ease of assembly and also to acoustically isolate the motor from the ultrasonic transducer assembly  530 , the hollow drive shaft  520  may be detachably coupled to the ultrasonic transducer stack  530  by a coupling assembly, generally designated as  540 . As can be seen in  FIGS. 9, 11, and 12 , the coupling assembly  540  may include a thin plate member  542  that is attached to a distal end  521  of the hollow drive shaft  520 . The thin plate member  542  may be fabricated from a material that has a relatively low stiffness in the axial direction and a high stiffness in rotation. See  FIG. 12 . For example, the thin plate member  542  may be fabricated from 0.008 inch thick Aluminum 7075-T651 and be attached to the distal end  521  of the hollow drive shaft  520  by, for example, by a press fit or brazing. The coupling assembly  540  may further include a proximal end mass or flange portion  531  of the ultrasonic transducer assembly  530 . The proximal end mass  531  may comprise, for example, a flange manufactured from stainless steel which is attached to the ultrasonic transducer assembly  530  by, for example, a bolted or other connection. As can be seen in  FIG. 11 , the end mass  531  has a hole  532  sized to receive the thin plate member  542  therein. In various embodiments, the thin plate member  542  may be sized to be pressed into the hole  532  such that rotation of the thin plate member  542  about axis A-A will cause the ultrasonic transducer assembly  530  to rotate about axis A-A. In other embodiments, a separate fastener plate (not shown) or snap rings (not shown) or snap features (not shown) may be provided to retain the thin plate member  542  in non-rotatable engagement with the end mass  531  of the ultrasonic transducer assembly  530 . Such arrangements serve to minimize the transmission of acoustic vibrations to the motor from the ultrasonic transducer assembly. 
       FIGS. 14 and 15  illustrate an alternative thin plate member  542 ′ that may be employed. In this embodiment, the thin plate member  542 ′ has a plurality of radial notches  544  provided therein to form radial tabs  546 . The hole  532  would be formed with notches (not shown) to accommodate the radial tabs  546  therein. Such arrangement may reduce the moment force applied to the shaft  520 . By employing the thin plate members  542 ,  542 ′ the amount of acoustic vibrations that are transferred from the ultrasonic transducer assembly  530  to the drive shaft  520  may be minimized. 
     When power is supplied to the motor  510 , the drive shaft  520  rotates bout axis A-A which also causes the transducer assembly  530  to rotate about axis A-A. When the clinician desires to power the ultrasonic transducer assembly  530 , power is supplied form the ultrasonic generator  12  to the fixed contact  156  in the slip ring assembly  150 . Power is transmitted to the ultrasonic transducer assembly  530  by virtue of rotational sliding contact or electrical communication between the inner contact  154  and the outer contact  156 . Those signals are transmitted to the ultrasonic transducer assembly  530  by conductors  151 ,  152 . The surgical instrument  500  may include a control arrangement of the type described above and be used in the various modes described above. It will be understood that the instrument  400  may be used in rotation mode, ultrasonic mode, rotation and ultrasonic mode (“duel mode”) or coagulation mode as described above. A suction may be applied between the blade  200  and outer sheath  230  through port  240 . A collection receptacle  243  and source of suction  240  may be attached to the port  240  by tube  242 . The distal end of the blade is exposed through a window in the distal end of the outer sheath  230  to expose the blade to tissue as will be further discussed below. 
       FIG. 16  illustrates another surgical instrument  600  wherein like numbers previously used to describe the various embodiments discussed above are used to designate like components. In these embodiments, the surgical instrument  600  includes a housing  302  that houses a transducer assembly  314  that is attached to an ultrasonic horn  324 . In this embodiment, the transducer assembly  314  and the ultrasonic horn  324  are attached to a PZT housing  602  that is rotatably supported within the housing  302  by a distal bearing  336 . The ultrasonic horn  324  may be coupled to the proximal end of the blade  200  in the manner described above. A nosepiece  160  may be attached to the housing  302  by fasteners  161  in the manner described above. 
     This embodiment includes a motor  510  that may comprise a stepper motor of the type and construction described above. The motor  510  may have an encoder associated therewith that communicates with the control module  24  ( FIG. 1 ) as was described above. The motor  510  may receive power from the motor drive  26  ( FIG. 1 ) through conductors  511 ,  512  that comprise motor cable  74  that extends through the common sheath  76 . The motor  510  has a hollow motor shaft  520  attached thereto that extends through a slip ring assembly  150 . The hollow drive shaft  520  is rotatably supported within the housing  302  by a proximal bearing  342 . 
     The slip ring assembly  150  is fixed (i.e., non-rotatable) within the housing  302  and includes a fixed outer contact  156  that is coupled to conductors  157 ,  158  that form generator cable  14  as was described above. An inner contact  154  is mounted on the rotatable hollow drive shaft  520  and is in electrical contact or communication with outer contact  156 . Conductors  151 ,  152  are attached to the inner contact  154  and extend through the hollow drive shaft  520  to be coupled to the ultrasonic transducer assembly  314 . In various embodiments, to facilitate ease of assembly and also acoustically isolate the motor  510  from the ultrasonic transducer assembly  314 , the hollow drive shaft  520  may be detachably coupled to the PZT housing  602  by a coupling assembly, generally designated as  540 . The coupling assembly  540  may include a thin plate member  542  that is attached to a distal end  521  of the hollow drive shaft  520 . As discussed above, the thin plate member  542  may be fabricated from a material that has a relatively low stiffness in the axial direction and a high stiffness in rotation. The PZT housing  602  has a proximal end portion  604  that has a hole  603  sized to receive the thin plate member  542  therein. In various embodiments, the thin plate member  542  may be sized to be pressed into the hole  603  such that rotation of the thin plate member  542  about axis A-A will cause the PZT housing  602  and ultrasonic transducer assembly  314  and ultrasonic horn  324  to rotate about axis A-A. In other embodiments, a separate fastener plate (not shown) or snap rings (not shown) or snap features (not shown) may be provided to retain the thin plate member  542  in non-rotatable engagement with the proximal end portion  604  of the PZT housing  602 . This embodiment could also employ the thin plate member  542 ′ as was discussed above. 
     When power is supplied to the motor  510 , the drive shaft  520  rotates about axis A-A which also causes the PZT housing  602  and ultrasonic transducer assembly  314  to rotate about axis A-A. When the clinician desires to power the ultrasonic transducer assembly  314 , power is supplied from the ultrasonic generator  12  to the fixed contact  156  in the slip ring assembly  150 . Power is transmitted to the ultrasonic transducer assembly  314  by virtue of rotational sliding contact or electrical communication between the inner contact  154  and the outer contact  156 . Those signals are transmitted to the ultrasonic transducer assembly  314  by conductors  151 ,  152 . The surgical instrument  500  may include a control arrangement of the type described above and be used in the various modes described above. It will be understood that the instrument  400  may be used in rotation mode, ultrasonic mode, rotation and ultrasonic mode (“duel mode”) or coagulation mode as described above. A suction may be applied between the blade  200  and outer sheath  230  through port  240 . A collection receptacle  243  and source of suction  240  may be attached to the port  240  by tube  242 . The distal end of the blade is exposed through a window in the distal end of the outer sheath  230  to expose the blade to tissue as will be further discussed below. 
     In an effort to reduce the overall size of the housing  302  employed in each of the instruments  300 ,  400 ,  500 , and  600 , the ultrasonic transducer assemblies employed in each of those respective instruments could be replaced with a half wave transducer that is physically shorter in length. 
     Ultrasonic Blade and Sheath Embodiments 
     Current arthroscopic tools include punches, reciprocating shavers, and radio frequency (RF) powered devices. Mechanical devices such as punches and shavers tend to create minimal tissue damage, but can sometimes leave behind ragged cut lines which are not desirable. RF powered blades can leave behind smoother cut lines and also ablate large volumes of soft tissue. However, such devices can create more tissue damage than pure mechanical instruments. The various non-limiting surgical instruments embodiments described above provide a host of advantages over conventional RF powered surgical instruments as well as conventional mechanical shavers that employ a rotating tissue cutting member. As will be discussed in further detail below, additional advantages may be realized by employing the unique and novel blade and sheath configurations of various non-limiting embodiments. 
       FIGS. 17-21  illustrate one form of blade  200  and outer sheath  230  that may be employed in connection with the various surgical instruments described above. As can be seen in those Figures, the blade  200  may have a distal end portion  700  and the outer sheath  230  may have a distal end portion  720 . The blade  200  may be fabricated from, for example, titanium and the outer sheath  230  may be fabricated from, for example, Poly ether ether ketone (“PEEK”), Ultem®, or stainless steel. As was discussed above, the blade  200  may have a waveguide or proximal end portion that is configured to be threadably or otherwise attached to an ultrasonic horn  324  ( FIGS. 6-10 and 16 ) in a known manner. The distal end portion  700  of the blade  200  may have a curved tip portion  702  formed thereon. The curved tip  702  may have an arcuate top segment  704  that has a cutting edge  706  formed on each lateral side  705 . The cutting edges  706  may terminate distally in a common, substantially pointed distal end  708 . The pointed distal end  708  may be relatively blunted or the pointed distal end  708  may have a relatively sharpened point. As can be seen in  FIG. 20 , the pointed distal end  708  may curve inwardly to about the central axis A-A of the blade. As can be seen in  FIG. 19 , in various embodiments, the cutting edges  706  may not intersect each other but may be separated by a center portion  707 . As can be seen in  FIG. 20 , the blade  200  may have a reduced neck portion  710  that protrudes distally from a waveguide or proximal blade portion  712 . A node  714  may be established at the area where the neck portion  710  protrudes from the proximal portion  712 . 
     As can be seen in  FIG. 17 , the outer sheath  230  also has a distal end portion  720  that has a window or opening  722  formed therein to expose the distal end portion  700  of the blade  200 . As can be further seen in  FIG. 17 , the outer sheath  230  may comprise a hollow cylinder that has a substantially blunted end  724 . In various embodiments, the window  722  extends for one half of the circular cross-section of the sheath  230 . Such window configuration forms an arcuate ledge  725  that extends around the blunted end  724 . In various embodiments, the outer sheath  230  may be fabricated from, for example, Poly ether ether ketone (“PEEK”), Ultem®, or stainless steel. To prevent metal-to-metal contact between the cutting edges  706  on the distal end portion  700  of the blade  200  and the ledge  725 , a polymer fender  726  may be attached by, for example, adhesive or a T-slot around the ledge  724 . See  FIG. 17 . Fender  726  may be fabricated from, for example, Teflon®, silicone or other reduced or “low friction” material. The fender  726  may be sized to produce an interference fit of, for example, 0.005 inches with the cutting edges  706  and the pointed distal end  708 . 
     In use, as the blade  200  is rotated about axis A-A within the outer sheath  230  and introduced to tissue, the tissue is drawn into the window  722  by means of the suction applied between the inner sheath  220  ( FIG. 4 ), and the outer sheath  230  as was described above. The tissue drawn into the window  722  is then cut as the cutting edges  706  are rotated past the fender  726  and the cut tissue may pass between the inner sheath  220  and outer sheath  230  and out through the suction port  240  ( FIGS. 4, 6-10, and 16 ) to the collection receptacle  243  ( FIGS. 4, 6-10 , and  16 ). 
     In another embodiment, an axial suction passage  730  may be provided through the neck portion  710  of the blade  200 . See  FIG. 20 . The axial suction passage  730  may communicate with a transverse suction passage  732  in the area of node  714 . Thus, the cut tissue may pass through the passages  730 ,  732  and out between the inner sheath  220  and outer sheath  230  and out through the suction port  240  ( FIGS. 4, 6-10, and 16 ) to the collection receptacle  243  ( FIGS. 4, 6-10 , and  16 ).  FIG. 21  depicts an alternative embodiment wherein two exit passages  734 ,  736  communicate with the axial passage  730  and extend at an angle therefrom. In various embodiments, the exit passages  734 , 736  may extend from the axial passage  730  at an angle  738  of, for example, forty-five (45) degrees. Such arrangement may serve to reduce impedance and power losses during ultrasonic activation which might have otherwise resulted from water being drawn in through the window  722  in the outer sheath  230 . 
     In use, the clinician may elect to rotate the blade  200  within the outer sheath  230  without applying ultrasonic motion thereto. The clinician may also elect to apply ultrasonic motion to the rotating blade or the clinician may wish apply ultrasonic motion to a parked (non-rotating) blade to use the portion of the blade exposed in the window  722  to coagulate tissue. 
       FIG. 22  illustrates use of blade  200  in connection with an outer sheath  230  that has a distal end portion  750  that includes a distally protruding nose segment  752 . In various embodiments, the nose segment  752  may have an arcuate width “W” that comprises approximately ten (10) to thirty (30) percent of the circumference of the distal end portion  750  of the outer sheath  230 . The nose segment  752  may protrude distally from the end of the distal end portion  750  of the sheath  230  a length “L” that may be approximately 0.25 inches, for example. In alternative embodiments, a low friction fender or guard (not shown) may be applied to the sides  753  of the nose segment  752  if desired. These embodiments may operate in a similar manner to the previous embodiment. However, this embodiment has the added ability to cut tissue with the exposed tip. As with the other embodiments, the clinician may apply gross rotational motion to the blade  200  without ultrasonic motion or with ultrasonic motion. In another alternative method of use, the exposed tip  708  and partially exposed cutting edges  706  may be used to cut tissue when the blade is not being rotated or vibrated. 
       FIGS. 23-24  illustrate another non-limiting blade and outer sheath embodiment. In this embodiment, the blade  200  has a distal end portion  760  that is substantially similar to the distal end portion  700  of the blade configuration described above. However, the distal blade portion  760  does not hook inwardly to the same degree such that the blade tip  762  does not intersect the central axis A-A. See  FIG. 24 . As can be seen in  FIG. 23 , the window  722 ′ in the distal end portion  720  of the outer sheath  230  does not extend the entire distance from an end wall  725  to the blunt tip  724 . Thus, in this embodiment, the blunt tip  724  comprises a nose that extends more than 90° but less than 180° (i.e., angle “A” in  FIG. 23A  is greater than 90° but less than) 180°. 
       FIGS. 25 and 26  depict another non-limiting blade embodiment. In this embodiment, the blade  200 ′ may be substantially similar to blade  200  or any of the other blades described herein. In this embodiment, the distal end  700 ′ has a roughened upper surface  705 ′. Such roughened surface  705 ′ creates higher friction forces between the distal end portion  700 ′ of the blade  200 ′ and the tissue to draw the tissue into the window  722 ′ in the distal end portion  720  of the outer sheath  230  ( FIG. 26 ). By pulling more tissue into the window  722 , the leading cutting edge  706 ′ of the blade  200 ′ may have a higher likelihood of cutting the tissue cleanly. In various embodiments, for example, the roughened surface may be formed by knurling or the upper surface may be coated with a hard material such as diamond or the like 
       FIGS. 27-29  illustrate another non-limiting blade embodiment. In this embodiment, the blade  200 ″ may be substantially similar to blade  200  described herein. In this embodiment, the distal end  700 ″ has a series of radially extending cutting teeth  707  protruding outward from upper surface  705 ″ for pulling and cutting tissue as the blade  200 ″ is rotated within the outer sheath  230 . 
       FIGS. 30, 31, and 32A -D illustrate another non-limiting blade and outer sheath embodiment. During use of various instruments that employ a rotatable blade within an outer sheath, it has been experienced that the tissue may get “kicked out” of the sheath window as the blade rotates therein. This can lead to reduced cutting speeds as tissue is not adequately captured and held between the cutting edges. The blade  800  of this embodiment addresses such potential shortcomings. 
     As can be seen in  FIG. 30 , the blade  800  may be substantially the same as blade  200  except for the differences noted herein. In particular, the blade  800  may include a neck portion  803  that that terminates in a distal end portion  810 . The distal end portion  810  may have a somewhat curved tip  812 . A series of teeth  817  may be provided on at least one lateral side  813  or  815  of the distal end portion  810 . In the embodiment depicted in  FIGS. 32A-D , teeth  817  and  819  are formed on lateral sides  813 ,  815 , respectively, of the distal end portion  810 . The distal end portion  810  further has a somewhat domed top portion  821 . In the embodiment shown in  FIGS. 30-32D , the teeth  817  comprise relatively sharp points that define a series of arcuate openings  823  therebetween. Teeth  819  also comprise relatively sharp points that have a series of arcuate openings  825  therebetween. As shown in  FIG. 30 , an axial suction passage  805  may be provided through the neck portion  803  of the blade  800 . The axial suction passage  805  may communicate with a transverse suction passage  807  in the area of node  808 . Thus, the cut tissue may pass through the passages  805 ,  807  and out between the inner sheath (not shown) and outer sheath  850  and out through a suction port to a collection receptacle in the manner described hereinabove. Other suction path arrangements may also be successfully employed. 
     The outer sheath  850  may be substantially similar to the outer sheath  230  described above and have a distal sheath tip  852  attached thereto that has a window or opening  854  formed therein to expose the distal end portion  810  of the blade  800 . See  FIG. 31 . The outer sheath  850  may comprise a hollow cylinder fabricated from for example, stainless steel. In various embodiments, the window  854  extends for approximately one half of the circular cross-section of the sheath  850  and forms a blade opening  858  therein. The distal sheath tip  852  may be fabricated from metal such as, for example, stainless steel such that a relatively sharp cutting edge  860  extends around the blade opening  858 . For the purpose of explanation, the sharp cutting edge  860  has a first lateral cutting edge portion  862  and a second lateral cutting edge portion  864 . 
       FIGS. 32A-D  illustrate a sequential rotation of the blade  800  within the outer sheath  850 . Turning to  FIG. 32A  first, the blade  800  is shown being rotated in a counter clockwise “CCW” direction. As shown in that Figure, the cutting teeth  817  on the first lateral side  813  of the blade  800  are positioned to shear tissue (not shown) between the teeth  817  and the first lateral cutting edge portion  862  of the cutting edge  860 . When in that position, the arcuate openings  823  between the teeth  817  are exposed to collectively form a first lateral suction path  870  between the blade  800  and the distal sheath tip  852  to enable the tissue to be drawn therein by the suction being applied through the suction passage  805  ( FIG. 30 ). As the rotational sequence continues, the domed upper portion  821  of the blade  800  covers the opening  854  in the distal sheath tip  852  such that there are no exposed suction paths for tissue to enter into the opening  854 . As the blade continues through its rotation,  FIG. 32C  illustrates that the arcuate openings  825  between teeth  819  collectively form a second lateral suction path  872  between the second lateral cutting edge portion  864  and the blade  800  to enable tissue to be drawn therein. As the blade  800  continues to rotate in the CCW direction, a third suction path  874  is exposed to enable tissue to be further drawn into opening  854 . Thus, such arrangement permits a sequential opening of suction paths from one lateral side of the blade opening  858  to the other to facilitate better tissue cutting. In use, the clinician may elect to rotate the blade  800  within the outer sheath  850  without applying ultrasonic motion thereto. The clinician may also elect to apply ultrasonic motion to the rotating blade or the clinician may wish apply ultrasonic motion to a parked (non-rotating) blade to use the portion of the blade exposed in the opening  854  to coagulate tissue. 
       FIGS. 33 and 34  illustrate another blade embodiment  880  that may be substantially the same as blade  200  except for the differences noted below. In particular, the blade  880  may include a waveguide or proximal portion  882  that that terminates in a distal tissue cutting portion  884 . The proximal portion  882  of the blade  880  may be configured to be threadably or otherwise attached to an ultrasonic horn of any of the various embodiments discussed above. The distal tissue cutting portion  884  may have opposed arcuate channels  886 ,  888  formed therein. The first arcuate channel  886  may define a first cutting edge  890  and the second arcuate channel  888  may define a second cutting edge  892 . This blade embodiment may be used in connection with any of the outer sheath configurations described above. In the depicted embodiment, hollow outer sheath  900  is employed which may be similar to sheath  230  for example and include a distal sheath tip  901  that has rounded or blunted nose portion  902  and a window  904 . The hollow outer sheath  900  may be fabricated from, for example, stainless steel and the distal sheath tip  901  may be fabricated from metal such as, for example, stainless steel. The window  904  forms an arcuate cutting edge  906  that cooperates with the cutting edges  890 ,  892  on the blade  880  to shear off tissue as the blade  880  is rotated within the outer sheath  900  in the various manners described above. In at least one embodiment, the proximal portion  882  of blade  880  may be sized relative to the hollow outer sheath  900  such that a clearance is provided therebetween to enable a suction to be applied thereto in the manner described above, for example. As can be seen in  FIG. 34 , as the blade  880  rotates (represented by arrow “R”) the arcuate channels  886 ,  886  define openings  894 ,  896  between the distal end  884  of the blade  880  and the walls of the distal sheath tip  901  to enable tissue to be drawn therein by the suction (represented by arrows “S”) applied to the area between the inner wall of the outer sheath  900  and the neck  882  of the blade  800 . It will also be appreciated that the blade  880  may be rotated in a counter clockwise or clockwise direction or be selectively oscillated between such rotational directions and still effectively cut tissue drawn therein.  FIG. 34A  depicts an alternative sheath tip embodiment  901 ′ that is fabricated from a metal material such as, for example, stainless steel that has a series of serrated cutting teeth  905 ′ formed on each cutting edge  890 ′,  892 ′. 
       FIG. 35  depicts another blade embodiment  910  that may be substantially the same as blade  200  except for the differences noted below. In particular, the blade  910  may include a waveguide or proximal portion  912  that that terminates in a distal tissue cutting portion  914 . The proximal portion  912  of the blade  910  may be configured to be threadably or otherwise attached to an ultrasonic horn of any of the various embodiments discussed above. The distal tissue cutting portion  914  may have opposed channels  916  formed therein that cooperate to define a first cutting edge  920  and a second cutting edge  922 . This blade embodiment may be used in connection with any of the various outer sheath configurations described above and is designed to only rotate in a single direction “R” for tissue cutting purposes. As with the above-described embodiment, the arcuate channels  916  define openings between the tissue cutting portion  914  of the blade  910  and the inner walls of the distal sheath tip to enable tissue to be drawn therein as suction is applied to the area between the proximal portion  912  an the inner wall of the outer sheath. 
       FIG. 36  illustrates another surgical instrument  2000  wherein like numbers previously used to describe the various embodiments discussed above are used to designate like components. In these embodiments, the surgical instrument  2000  includes a housing  302  that houses an ultrasonic transducer assembly  314  that is attached to an ultrasonic horn  324 . In this embodiment, the ultrasonic transducer assembly  314  and the ultrasonic horn  324  may be non-rotatably supported within the housing  302  in a known manner. Electrical control signals may be supplied to the ultrasonic transducer assembly  314  from an ultrasonic generator  12  by conductors  151 ,  152 . Activation of the ultrasonic generator  12  will cause the ultrasonic transducer assembly  314  to apply ultrasonic motion to the ultrasonic horn  324 . In this embodiment, a hollow outer sheath  2010  is coupled to the ultrasonic horn  324  for receiving ultrasonic motion therefrom. For example, in various embodiments, the outer sheath  2010  may be coupled to the ultrasonic horn  324  by a threaded connection or other suitable fastening arrangement. 
     This embodiment includes a rotatable blade  2020  that is rotatably supported within the outer sheath  2010  and is coupled to a motor  510  supported within the housing  302 . The motor  510  may, for example, comprise a stepper motor of the type and construction described above. The motor  510  may have an encoder associated therewith that communicates with a control module  24  ( FIG. 1 ) as was described above. The blade  2020  may have a hollow distal portion  2022  and a solid proximal portion  2024 . See  FIG. 36A . The solid proximal portion  2024  may be attached to the motor drive shaft  520  by a threaded or other suitable connection. The motor drive shaft  520  may be rotatably supported within the housing  302  by a proximal bearing  342 . When control signals are supplied to the motor  510 , the drive shaft  520  rotates about axis A-A which also causes the blade  2020  to rotate about axis A-A within the outer sheath  2010 . 
     As can be further seen in  FIG. 36A , the hollow outer sheath  2010  is supported within a hollow nosepiece  160  that has a suction port  240  therein. A flexible tube  242  may be attached to the suction port  240  and communicate with a collection receptacle  243  that is coupled to a source of suction, generally depicted as  244 . The hollow sheath  2010  may be supported within the nosepiece  160  by a proximal seal  2013  and a distal seal  2015  which are located on each side of the suction port  240  as shown in  FIG. 36A  and which serve to establish fluid tight seals therebetween. The hollow sheath  2010  is provided with at least one proximal sheath opening  2014  in registration with the suction port  240  between the proximal seal  2013  and the distal seal  2015 . In addition, the hollow distal portion  2022  of the blade  2020  is rotatably supported within the hollow sheath  2010  by at least a proximal blade seal  2025  and a distal blade seal  2027 . At least one blade discharge port  2028  may be provided through the hollow portion  2022  of the blade  2020  between the proximal blade seal  2025  and the distal blade seal  2027  to discharge into the at least one proximal sheath opening  2014 . 
     Also in various embodiments, a distal end portion  2011  of the hollow outer sheath is closed and at least one opening or window  2012  is provided therein to expose a distal tissue cutting portion  2025  of the blade  2020 . In at least one embodiment window  2012  comprises an elongated slot and the distal tissue cutting portion also comprises an elongated slot  2026  in the blade  2020  ( FIGS. 37 and 38 ). Thus, suction may be applied from the suction source  244  into the hollow portion of blade  2020  through the port  240 , the proximal sheath opening  2014  and the blade discharge port  2028 . As the distal openings  2026 ,  2012  coincide, tissue “T” may be drawn into the hollow distal portion  2022  of blade  2020  as shown in  FIG. 38 . The severed portions of tissue “T” may pass through the hollow distal portion  2022  of blade  2020  and out through openings  2028 ,  2014  and into the collection receptacle  243 . 
     In use, the clinician may activate the rotating blade  2020  to cut and evacuate tissue. When a bleeder is encountered, the clinician may activate the ultrasonic transducer assembly  314  to send ultrasonic motions to the outer sheath  2010  for coagulation purposes. For example, spinal fusion surgeries require the removal of disc material due to a variety of disease states. Often times this material is toughened and requires quite a bit of force with conventional instrumentation to break up the disc and remove its fragments. Once the disc material is removed, the end plates must be scraped to reveal fresh surfaces to promote fusion of the plates to the cage. The plates must also be shaped to provide a good fit with the type of cage being used. Conventional instrumentation generally requires high forces from the surgeon very close to critical structures. In other embodiments, the motor may be coupled to rotate the ultrasonic transducer assembly and the blade may be attached to the ultrasonic transducer assembly as was described above so that the blade rotates and may have ultrasonic motion applied thereto. 
     Use of the above-described surgical instrument  2000  may be particularly advantageous when performing, for example, a discectomy as shown in  FIGS. 39 and 40 . As can be seen in those drawings, the outer sheath  2010  may be inserted into the disc “D”. The rotating blade  2020  may be used to shave off small pieces of disc and suction them out. Such arrangement eliminates the need for repeated insertion/removal of surgical tools. The device may also be employed to prepare the vertebrae endplates. In the embodiment depicted in  FIGS. 41-45 , the rotatable cutting blade  2020  has a series of serrated teeth  2021  formed on at least one side of the distal opening  2026  to further assist with the cutting of tissue drawn in through the opening  2012  in the outer sheath  2010 . Also in this embodiment, a retractable safety shield  2040  is movably mounted on the outer sheath  2010  and is selectively movable from a closed position substantially covering the opening  2012  in the outer sheath  2010  to an open position exposing the opening  2012  ( FIGS. 43 and 44 ). Such arrangement covers the teeth  2021  on the blade  2020  during insertion and removal of the outer sheath  2010  adjacent vital nerves and other critical tissues. To facilitate movement of the safety sheath  2040  on the outer sheath  2010 , a thumb control tab  2042  ( FIGS. 41 and 45 ) may be formed on the proximal end of the safety sheath  2040  to enable the clinician to apply sliding actuation forces thereto. In addition, in various embodiments, a retainer protrusion  2044  may be formed on the safety sheath  2040  to engage at least one detent or groove  2046  provided in the outer sheath  2010  to retain the safety sheath  2040  in a corresponding open or closed position. For example, one detent or groove  2046  may correspond to a closed position (wherein the safety sheath  2040  covers the opening  2012 ) and another detent or groove  2046 ′ may correspond to a partially opened position (wherein a portion of the opening  2012  is exposed) and another detent or groove  2046 ″ may correspond to a fully opened position (wherein the opening  2012  is fully exposed). 
       FIGS. 46-51  illustrate a blade  940  that has a nearly straight distal tissue cutting portion  942 . Such blade configuration may reduce potential impedance and power increases when the blade  940  is used in an aqueous environment when compared to the impedance and power requirements of various other blade configurations when used in that environment. That is, such relatively straighter blade designs may require less power to operate in an aqueous environment. The blade  940  may have a round or blunted distal end  944  and a groove  946  that forms cutting edges  947 ,  948  for cutting tissue when the blade  940  is used in connection with an outer sheath  230  as described above. The groove may have a length “L” of, for example, one (1) inch. The blade  942  may also have a suction passage  730  of the type and construction described above. As shown in  FIG. 47 , a low friction fender or pad  726  of the type and construction described above may be employed around the exposed distal end portion  720  of the outer sheath  230 .  FIGS. 48-51  depict alternative cross-sectional shapes of a blade  940  where differently shaped grooves  946  are employed. 
       FIGS. 52-55  depict another non-limiting blade and sheath embodiment. This embodiment employs a hollow outer sheath  950  that may be attached to the nosepiece or the ultrasonic transducer assembly of any of the surgical instruments described above by any suitable fastening method or connection arrangement. As can be seen in  FIG. 55 , the outer sheath  950  has a closed rounded or blunted nose portion  952  and an elongated rectangular-shaped window or opening  954 . In one embodiment, for example, the rectangular-shaped window  954  has a width “W” that is approximately one-fourth of the circumference of the hollow outer sheath  950  and a length of approximately 0.25 inches. The sheath  950  may be fabricated from, for example, stainless steel. 
     This embodiment also employs a blade  960  that can be used in connection with any of the surgical instrument embodiments described above or others. For example, a waveguide or proximal portion of the blade may be configured for attachment to the instrument&#39;s ultrasonic horn or motor drive shaft by a threaded or other connection. As can be seen in  FIGS. 52-54 , the blade  960  has a pair of radially-opposed sharpened cutting edges  962  formed thereon that serve to cut tissue “T” that is drawn into the window  954  of the outer sheath  950 . In various embodiments, the blade  960  may be fabricated from, for example, Titanium and be sized relative to the outer sheath  950  such that a clearance “C” is provided between the inner wall  951  of the outer sheath  950  and the tips of the radially opposed sharpened cutting edges  962 . See  FIG. 54 . In some embodiments, for example, the clearance “C” may be approximately 0.001 inches. In this embodiment, the blade  960  may be fabricated from, for example, Titanium and have a flattened distal end  964 . In use, when gross rotary motion is applied to the blade  960  in any of the various manners described above and suction is applied within the hollow outer sheath  950 , the tissue “T” is drawn in through the window  954  and trapped between the blade  960  and the inner wall  951  of the outer sheath  950 . This action isolates the tissue “T” long enough to cut when, for example, the device is employed in an aqueous environment as will be discussed in further detail below. In some embodiments, the cutting edges  962  may be serrated. In other embodiments the cutting edges  962  are not serrated. 
       FIG. 57  depicts another non-limiting blade and sheath embodiment. This embodiment employs a hollow outer sheath  970  that may be attached to the nosepiece or ultrasonic transducer assembly of any of the various instruments described above. As can be seen in  FIG. 56 , the outer sheath  970  has a rounded or blunted nose portion  972  and an elongated window or opening  974  that forms a blade access hole  976  in the nose portion  972  and two radially-opposed lateral window portions  978 . In one embodiment, for example, wherein the outer diameter of the outer sheath  970  is approximately 0.157 inches, the diameter of the blade access hole  976  may be approximately 0.125 inches. The lateral window portions  978  may each have a width “W” of approximately 0.090 inches and a length “L” of approximately 0.25 inches. Other window sizes/configurations may be employed. The sheath  970  may be fabricated from, for example, stainless steel. 
     This embodiment also employs a blade  980  that has a waveguide or proximal portion that is configured for attachment to the ultrasonic horn or motor drive shaft of any of the various surgical instrument embodiments described above  324  by a threaded or other suitable connection. In various embodiments, the blade  980  may be substantially the same as blade  960  described above (with radially-opposed sharpened cutting edges  982 ), except that blade  980  has a rounded/substantially blunted distal tip portion  984  that protrudes out through the blade access hole  976  in the outer sheath  970 . See  FIG. 57 . In various embodiments, the blade  980  may be fabricated from, for example, Titanium and be sized relative to the outer sheath  970  such that a clearance is provided between the inner wall  971  of the outer sheath  970  and the tips of the radially opposed sharpened cutting edges  962 . In some embodiments, for example, the clearance may be approximately 0.001 inches. In use, when gross rotary motion is applied to the blade  980  in any of the various manners described above and suction is applied within the hollow outer sheath  970 , the tissue is drawn in through the window portions  978  and trapped between the blade  980  and the inner wall  971  of the outer sheath  970 . This action isolates the tissue long enough to cut when, for example, the device is employed in an aqueous environment as will be discussed in further detail below. Also, in this embodiment, when the blade  980  is ultrasonically powered, the clinician can use the exposed distal tip portion  984  for spot ablation of fibrous tissue or for spot coagulation purposes. In some embodiments, the cutting edges  982  may be serrated. In other embodiments the cutting edges  982  are not serrated. 
       FIG. 59  depicts another non-limiting blade and sheath embodiment. This embodiment employs a hollow outer sheath  990  that may be attached to the nosepiece or ultrasonic transducer assembly of any of the above-described surgical instruments by any suitable fastening method or connection arrangement. As can be seen in  FIG. 58 , the outer sheath  990  has a closed rounded or blunted nose portion  992  and an elongated rectangular-shaped window or opening  994 . In one embodiment, for example, the rectangular-shaped window  994  has a width “W” that is approximately 0.100 inches and a length of approximately 0.25 inches. The sheath  990  may be fabricated from, for example, a polyamide or similar material that does not result in the heating of a blade  1000  from contact therewith. The window  994  may be defined by sharp edges  995 ,  997 . As can be seen in  FIG. 60 , edges  995 ,  997  may be provided with an angle “B” therebetween. In some embodiments, angle “B” may be approximately 110 degrees. 
     These embodiments also employ a blade  1000  that has a waveguide or proximal portion that is configured for attachment to the ultrasonic horn or motor drive shaft of any of the above-described surgical instruments or others by a threaded or other suitable connection arrangement. As can be seen in  FIG. 59 , the blade  1000  may have a pair of radially-opposed sharpened cutting portions  1002  formed thereon that serve to cut tissue that is drawn into the window  994  in the outer sheath  990 . In various embodiments, the blade  1000  may be fabricated from, for example, Titanium. The cutting portions  1002  of the blade  1000  may have sharp cutting corners  1003  formed thereon. In some embodiments, the cutting corners  1003  may be serrated. In other embodiments the cutting corners  1003  are not serrated. The cutting portions  1002  may be sized relative to the outer sheath  990  to establish a tissue shearing action between the cutting corners  1003  and the sharp edges  995 ,  996  of the window opening  994  as the blade  1000  is rotated or oscillated back and forth within the outer sheath  990 . The blade  1000  may be sized relative to the outer sheath  990  to create a slip fit therebetween that otherwise prevents tissue from becoming trapped between those two components. The blade  990  could rotate back and forth (arrow “D”) or rotate in a single direction (arrow “E”) and if desire be ultrasonically activated as well as was discussed above. See  FIG. 59 . In use, when gross rotary motion is applied to the blade  1000  in any of the various manners described above and suction is applied within the hollow outer sheath  990 , the tissue “T” is drawn in through the window  994  and trapped between the blade  1000  and the inner wall  999  of the outer sheath  990 . This action isolates the tissue long enough to cut when, for example, the device is employed in an aqueous environment as will be discussed in further detail below. 
       FIG. 62  depicts another non-limiting blade and sheath embodiment. This embodiment employs a hollow outer sheath  1010  that may be attached to the nosepiece or ultrasonic transducer assembly of any of the above described surgical instruments by any suitable fastening method or connection arrangement. As can be seen in  FIG. 61 , the outer sheath  1010  may have a closed rounded or blunted nose portion  1012  and an elongated rectangular-shaped window or opening  1014 . In one embodiment, for example, the window  1014  has a first coined or depressed edge  1016  and a second coined or depressed edge  1018  to define an opening  1019  that may have a width W″ that is approximately 0.100 inches. Window  1014  may have a length of approximately 0.25 inches. The sheath  1010  may be fabricated from, for example, stainless steel 
     These embodiments also employ a blade  1020  that has a waveguide or proximal portion that is configured for attachment to the ultrasonic horn or motor drive shaft of any of the above-described surgical instruments or others by a threaded or other suitable connection. As can be seen in  FIG. 62 , the blade  1020  may have a pair of radially-opposed sharpened cutting portions  1022 ,  1024  formed thereon. The blade  1020  may be fabricated from, for example, Titanium and have relative sharp cutting corners  1025  formed on each cutting portions  1022 ,  1024 . In some embodiments, the cutting corners  1025  may be serrated. In other embodiments the cutting corners  1025  are not serrated. The cutting portions  1022 ,  1024  may be sized relative to the outer sheath  1010  to establish a tissue shearing action between the depressed edges  1016 ,  1018  and the cutting corners  1025  as the blade  1020  is rotated or oscillated within the outer sheath  1010 . Such arrangement forms a relatively small localized area to lessen contact issues between the blade and the outer sheath by also facilitates a scissoring effect on the tissue. In use, when gross rotary motion is applied to the blade  1020  in any of the various manners described above and suction is applied within the hollow outer sheath  1010 , the tissue is drawn in through the opening  1019  and trapped between the blade  1020  and the inner wall  1011  of the outer sheath  1010 . This action isolates the tissue long enough to cut when, for example, the device is employed in an aqueous environment as will be discussed in further detail below. 
       FIG. 64  depicts another non-limiting blade and sheath embodiment. This embodiment employs a hollow outer sheath  1030  that may be attached to the nosepiece or ultrasonic transducer assembly of any of the above-described surgical instruments. As can be seen in  FIG. 63 , the outer sheath  1030  may have a closed rounded or blunted nose portion  1032  and an elongated rectangular-shaped window or opening  1034 . This embodiment may further include a pair of sharpened cutting inserts  1036 ,  1038 . The cutting inserts  1036 ,  1038  may be fabricated from, for example, hardened stainless steel and be attached within the hollow sheath  1030  by, for example, welding. Window  1034  may have a width W″ that is approximately 0.100 inches and a length of approximately 0.25 inches. The sheath  1030  may be fabricated from, for example, stainless steel. 
     These embodiments also employ a blade  1040  that has a waveguide or proximal portion that is configured for attachment to the ultrasonic horn or motor drive shaft of any of the surgical instruments described herein or others by a threaded or other suitable connection. As can be seen in  FIG. 64 , the blade  1040  has a pair of radially-opposed cutting portions  1042  formed thereon that have relatively sharp cutting corners  1043 . In some embodiments, the cutting corners  1043  may be serrated. In other embodiments the cutting corners  1043  are not serrated. In various embodiments, the blade  1040  may be fabricated from, for example, Titanium and be sized relative to the cutting inserts  1036 ,  1038  to establish a tissue shearing action between the sharp cutting corners  1043  and the cutting portions  1042  as the blade  1020  is rotated or oscillated within the hollow outer sheath  1030 . The outer diameter of the blade  1020  is smaller than the inner diameter of the outer sheath  1030  to provide clearance for the blade  1040  during operation. The only instance of contact would be between the cutting portions  1042  of the blade  1040  and the inserts  1036 ,  1038  along the window opening  1034  wherein the tissue is pulled in by the suction. 
       FIG. 66  depicts another non-limiting blade and sheath embodiment. This embodiment employs a hollow outer sheath  1110  that may be attached to the nosepiece or ultrasonic transducer assembly of any of the surgical instruments described above by any suitable fastening method or connection arrangement. As can be seen in  FIG. 65 , the outer sheath  1110  may have a closed rounded or blunted nose portion  1112  and an elongated rectangular-shaped window or opening  1114 . In this embodiment, the lateral edge portions  1116 ,  1118  of the window  1114  are coined or depressed inward. Window  1014  may have a width W″ that is approximately 0.10 inches and a length of approximately 0.25 inches. 
     These embodiments also employ a blade  1120  that has a waveguide or proximal portion that is configured for attachment to the ultrasonic horn or motor drive shaft of any of the surgical instrument embodiments described above or others by a threaded or other suitable connection arrangement. As can be seen in  FIG. 66 , the blade  1120  has a pair of radially-opposed cutting portions  1122  formed thereon that have relatively sharp cutting corners  1023 . In some embodiments, the cutting corners  1023  may be serrated. In other embodiments the cutting corners  1023  are not serrated. In various embodiments, the blade  1020  may be fabricated from, for example, Titanium and be sized relative to the depressed edges  1116 ,  1118  to establish a tissue shearing action between the sharp cutting corners  1023  and the cutting portions  1122  as the blade  1120  is rotated or oscillated. Such arrangement defines a larger clearance C 1  between the cutting portions  1122  of the blade  1120  and the inner wall  1111  of the sheath  1110 . To form a tissue shearing action between the lateral edges  1116 ,  1118  and the cutting portions  1122 , a clearance C 2  that is less than C 1  is provided. 
       FIGS. 67-69  depict another non-limiting blade and sheath embodiment. This embodiment employs a hollow outer sheath  1210  that may be attached to the nosepiece or ultrasonic transducer assembly of any of the surgical instruments described above. The hollow outer sheath  1210  has a distal nose portion  1212  that includes an upper opening  1214  and a lower opening  1215  that serve to define arcuate lateral side portions  1216 ,  1218 . The distal nose portion  1212  may further have a closed end  1219  that extends between the lateral side portions  1216 ,  1218 . 
     This embodiment further comprises a blade  1220  that has a waveguide or proximal portion that is configured for attachment to the ultrasonic transducer assembly of any of the surgical instruments described above. The blade  1220  further has a distal end portion  1221  that has a cavity  1222  that serves to define a pair of arcuate cutting portions  1224 ,  1226  that extend above the arcuate lateral side portions  1216 ,  1218  of the hollow sheath  1210 . One, both or neither of the cutting portions  1224 ,  1226  may have serrated teeth  1227 . In the embodiment depicted in  FIG. 67 , the cavity  1222  has a cross-sectional shape that roughly resembles a flat bottom “C”. However, the cavity  1222  may have other cross-sectional shapes. At least one suction passage  1230  may be provided through the blade  1220  as shown. The suction passage may communicate with a source of suction (not shown). 
     In various embodiments, the blade  1220  may be fabricated from, for example, Titanium and be sized relative to the distal nose portion  1212  of the hollow sheath  1210  such that the bottom portion  1232  of the blade  1220  extends downward beyond the lateral sides  1216 ,  1218  of the nose portion  1212 . Likewise, the cutting edges of the arcuate side portions  1224 ,  1226  extend above the lateral sides  1216 ,  1218  as shown in  FIG. 67 . The exposed bottom portion  1232  of the blade  1220  may be used, for example, to coagulate tissue, while the cutting edges  1224 ,  1226  may be used to cut and sever tissue. 
     The proximal end  1211  of the hollow sheath  1210  protrudes from a handle housing  1240  as shown in  FIG. 70 . The handle housing  1240  houses an ultrasonic transducer assembly, a motor, and a slip ring assembly as was described above and is coupled to a control system  10 . The handle housing  1240  may include a selector switch  1241  which enables the clinician to switch between a first “ultrasonic” mode  1242 , a second “shaver” mode  1244 , and a third “injection” mode  1246 . The switching mechanism  1241  communicates with the control system  10  to automatically orient the blade  1220  in a desired rotational orientation. For example, to employ the device  1200  in the ultrasonic mode  1242 , the clinician switches the selector switch  1241  to the ultrasonic mode position  1242  (depicted as action  1250  in  FIG. 71 ). When in the first ultrasonic configuration  1242 , the motor will rotate the blade  1220  to the position shown in  FIGS. 67 and 68  (depicted as action  1252  in  FIG. 71 ) and then park it in that position to expose the bottom portion  1232  of the blade  1220  through the hollow sheath  1210  (depicted as action  1254  in  FIG. 71 ). When in that position, the ultrasonic transducer assembly is activated to enable the bottom portion  1232  to be used to achieve hemostasis (depicted as action  1257  in  FIG. 71 ). More particularly, when in the ultrasonic mode  1242 , the clinician may orient the bottom portion  1232  against the tissue that is bleeding and then apply firm pressure to the tissue (depicted as action  1256  in  FIG. 71 ) with the exposed portion  1232  of the blade  1220 . The clinician then activates the ultrasonic transducer assembly to achieve hemostasis (depicted as action  1258  in  FIG. 71 ). In alternative embodiments, the device  1200  may be provided with a series of switches/buttons as was described above that communicate with a control system such that activation of one switch may initiate rotation. Activation of another switch may initiate rotatable oscillation and activation of another switch may, in cooperation with the control system rotate the blade to the ultrasonic position and park it and thereafter activate the ultrasonic transducer assembly or in still other embodiments, the ultrasonic transducer assembly may be activated by yet another separate switch. All of such alternative arrangements are within the scope of the various non-limiting embodiments disclosed herein and their respective equivalent structures. 
       FIG. 72  illustrates use of the device  1200  when in the shaver mode  1244 . In particular, the selector switch  1241  is moved to the shaver position  1242  (depicted as action  1260  in  FIG. 72 ). When in that position, the motor continuously rotates the blade  1220  within the hollow outer sheath  1210  (depicted as action  1262  in  FIG. 72 ). In other embodiments, the motor may rotatably oscillate the blade  1220  back and forth within the outer sheath  1210  or in other embodiments, the selector switch may be movable to yet another position wherein the rotatable oscillation is initiated. In either case, the clinician may then contact tissue with the rotating or oscillating blade ( 1220 ) to cause the tissue to be shaved and evacuated through the suction passage  1230  (depicted as action  1264  in  FIG. 72 ). 
       FIG. 73  illustrates use of the device  1200  when in the injection mode  1246 . In particular, the selector switch  1241  is moved to the injection position  1246  (depicted as action  1270  in  FIG. 73 ). When in that position, the blade  1220  is retained in a parked position (depicted as action  1272  in  FIG. 73 ). The clinician may then orient the blade in a desired position and then inject the desired medicament (depicted as action  1274  in  FIG. 73 ). One form of medicament that may be injected for example may comprise a cell generating drug sold under the trademark “Carticel”. However, other drugs and medicaments could be employed. The injection action may be accomplished by orienting the blade  1220  to a position within the outer sheath  1210  such that a medicament passage  1284  extending through the blade  1220  is exposed through the outer sheath  1210  to enable medicament to be advantageously applied to the adjacent site. The medicament may then be injected by activating a pump  1280  that communicates with a source of the medicament  1282 . See  FIG. 70 . In various embodiments, the device  1200  may have an injection trigger  1249  that communicates with the pump  1280  such that activation of the injection trigger  1249  will cause the pump  1280  to inject the medicament out through the passage  1284  ( FIG. 68 ). In alternative embodiments, the medicament may be manually injected by, for example, a syringe into a port (not shown) that communicates with medicament passage  1284  in blade  1220 . 
       FIGS. 74-77  depict another non-limiting surgical instrument embodiment  1300 . The device  1300  may include any one of the handpiece devices  300 ,  400 ,  500  described above. For example, the device  1300  may include a handpiece  300  that incorporates the difference noted below. The handpiece  300  includes a blade  200  that has a waveguide or proximal portion that is coupled to an ultrasonic transducer assembly that, when activated, applies ultrasonic motion to the blade  200 . The blade  200  may also be rotated by the motor arrangement contained within the handpiece  300  as described above. The blade  200  may extend through an inner sheath  1320  that protrudes from the handpiece  300 . The blade  200  is free to be selectively vibrated and rotated within the inner sheath  1320 . One or more seal members  1322  may be provided between the blade  200  and the inner sheath  1320  to prevent fluids and tissue from entering the area between the inner sheath  1320  and the blade  200 . The seal members  1322  may be fabricated from, for example, silastic silicone. 
     The device  1300  may further include an outer sheath  1330  that is movably received on the inner sheath  1320 . The outer sheath  1330  may be sized relative to the inner sheath  1320  such that a suction tube  1350  may extend between a portion of the inner sheath  1320  and a portion of the outer sheath  1330 . The suction tube  1350  may communicate with a source of suction generally depicted as  1352 . See  FIG. 74 . As can be seen in  FIGS. 74-77 , the outer sheath  1330  may include a swing arm portion  1332  that protrudes distally from a distal end portion  1331  of the outer sheath  1330 . The swing arm  1332  may be relatively straight ( FIG. 75 ) or it may have a slightly curved distal end  1334  ( FIG. 76 ). As can be seen in  FIG. 76 , the distal end  1334  may have a sharpened cutting surface  1336  thereon. As can also be seen in  FIGS. 74-76 , in some embodiments, the blade  200  may have a curved blade tip  1360  that has a pair of lateral cutting edges  1362  formed thereon. In other embodiments, the blade tip  1360  may be straight. In some embodiments, the blade  200  may be rotated in the various manners discussed above. In other embodiments, the blade  200  may not rotate. In such embodiments, for example, the clinician may choose not to activate the motor for rotating the blade or the handpiece may comprise a handpiece that does not include a motor for rotating the blade. 
     In use, the swing arm portion  1332  may cover portions of the distal end  1360  of the blade  200 . In one mode of use, the outer sheath  1330  is retained in position wherein the swing arm portion  1332  covers the back side of the blade  200  as shown in  FIG. 74 . Such arrangement leaves the curved blade tip  1360  exposed. When in such position, for example, the curved blade tip  1360  could be employed to transect tissue, such as the meniscus. In a second mode of operation, the swing arm portion  1332  is moving. 
     In the embodiment depicted in  FIGS. 74-77 , a suction tube  1350  is employed to draw loose tissue towards the blade tip  1360  and also remove small sections of transected tissue during cutting. In other embodiments, suction could occur in the annular space between the sheaths  1320 ,  1330 . In still other embodiments, the blade  200  may have a suction path (not shown) extending therethrough which ultimately communicates with a source of suction as was described above. Such suction path would most likely exit the blade  200  at the node at the proximal end. In still other embodiments, no suction is employed. 
     In some embodiments, the swing arm portion  1332  may be permanently retained in position against the blade  200 . In still other embodiments, a lubricious or low friction pad (not shown) may be mounted to the swing arm portion  1332  such that the pad contacts the blade  200 . In other embodiments, a 0.002″-0.010″ clearance may be provided between the swing arm portion  1332  and the blade  200 . In other embodiments, the swing arm portion  1332  extends around the length of the curved portion of the blade  200  so that the entire blade  200  is covered from the back side. 
     The various non-limiting embodiments described hereinabove may be effectively employed in a connection with a variety of different surgical applications and are particularly well-suited for cutting and coagulating tissue in the aqueous environment of arthroscopic surgery. In such applications, however, if fluid passes between the blade or waveguide and the inner sheath, the fluid may enter the housing and damage the components therein. Various sealing arrangements are known for use with ultrasonically powered surgical instruments. For example, U.S. Pat. Nos. 5,935,144 and 5,944,737, the disclosures of which are each herein incorporated by reference in their respective entireties, each disclose various sealing arrangement for use with ultrasonic surgical instruments in the traditional environment of laparoscopic surgery and open surgery (i.e., non-aqueous environments). However, various non-limiting embodiments discussed below employ improved sealing arrangements that may be better suited for use in aqueous environments. 
     More particularly and with reference to  FIG. 78 , there is shown an ultrasonic device  1400  that includes a housing  1402  that rotatably supports an ultrasonic transducer assembly  1404  therein. For example, the ultrasonic transducer assembly  1404  may be rotatably supported within the housing  1402  by a series of bearings (not shown). An ultrasonic horn  1406  may be coupled to the ultrasonic transducer assembly  1404  and an ultrasonic implement  1410  is attached thereto by conventional means which may typically comprise a threaded arrangement. As used herein, the term “ultrasonic implement” may encompass any one of the blade and cutting member embodiments described herein. The portion of the ultrasonic implement  1410  that is coupled to the ultrasonic horn  1406  may be referred to as a waveguide portion  1412 . The waveguide  1412  may comprise an integral portion of the ultrasonic implement  1410  or it may comprise a separate component attached thereto by, for example, a threaded connection. In the embodiment depicted in  FIG. 78 , the ultrasonic implement  1410  extends through a hollow outer sheath  1420 . The outer sheath  1420  and the distal end of the ultrasonic implement  1410  may be configured in any one of the various blade and sheath configurations described hereinabove as well as others. 
     As can also be seen in  FIG. 78 , a proximal shaft  1430  is attached to the ultrasonic transducer assembly  1404 . Attached to the proximal shaft  1430  is a driven gear  1432  that is in meshing engagement with a drive gear  1434  coupled to an out put shaft  1436  of a motor  1440 . Ultrasonic electrical signals and the motor control signals may be supplied from the control system  10  through a slip ring assembly  1450  of the type and construction described above. The device  1400  may further comprise the various control button arrangements described above, so that the device may be used in an ultrasonic mode, a non-ultrasonic mode (e.g., rotational shaving mode) and a combination of such modes. Unlike the various instruments described above, the motor  1440  is not coaxially aligned with the ultrasonic transducer assembly. 
       FIG. 79  depicts a non-limiting embodiment of a seal assembly  1470  that may be employed between in the waveguide or proximal portion  1412  of the ultrasonic implement  1410  and the outer sheath  1420 . The seal  1470  comprises an annular member that may be fabricated from silicon or other materials such as, for example, Ultem® and is over molded or otherwise sealingly attached to the waveguide  1412  at a node “N”. The seal  1470  may have a first annular seal portion  1472  that is molded onto the waveguide  1412  at a node “N” and two axial seal portions  1474 ,  1476  that extend axially in opposite axial directions beyond the first annular seal portion  1472  and which are separated by a groove  1478 . The groove  1478  may enable the two axial seal portions  1474 ,  1476  to somewhat flex relative to each other in sealing contact with the outer sheath  1420 . The narrower first annular seal portion  1472  may avoid excessive heat build-up while providing a wider contact area wherein the seal  1470  contacts the outer sheath  1420 . 
       FIG. 80  depicts anon-limiting embodiment of a seal  1480  that may be employed between in the waveguide or proximal portion  1412  of the ultrasonic implement  1410  and the outer sheath  1420 . The seal  1480  comprises an annular member that may be fabricated from silicon or other materials, such as for example, Ultem® and is over molded or otherwise sealingly attached to the waveguide  1412  at a Node “N”. The seal  1480  may be arranged to abut an inwardly-extending annular abutment ring  1490  formed on the outer sheath  1420 . The seal  1480  is located distal with respect to the abutment ring  1490 . When the fluid pressure builds up within the distal end of the outer sheath  1420 , the seal  1480  is forced into the abutment ring  1490  thereby increasing the strength of the seal. The outer sheath  1420  may be fabricated from, for example, stainless steel. 
       FIG. 81  depicts a non-limiting embodiment of a seal  1500  that may be employed between in the waveguide portion  1412  of the blade  1410  and the outer sheath  1420 . The seal  1500  comprises an annular member that may be fabricated from silicon or other materials, such as for example, Ultem® and is over molded or otherwise sealingly attached to the waveguide  1412  at a Node “N”. The seal  1480  may be arranged to be received within an annular groove  1423  provided in the outer sheath  1420 . The outer sheath  1420  may be fabricated from, for example, stainless steel. 
       FIG. 82  depicts a non-limiting embodiment of a seal  1510  that may be employed between in the waveguide or proximal portion  1412  of the ultrasonic implement  1410  and the outer sheath  1420 . The seal  1510  comprises an annular member that may be fabricated from silicon or other materials such as, for example, Ultem® and is over molded or otherwise sealingly attached to the waveguide  1412  at a node “N”. The seal  1510  may have an inner rim portion  1512  that is molded onto the waveguide  1412  at a node “N” and two axial seal portions  1514 ,  1516  that extend axially in opposite directions beyond the inner portion  1512  and which are separated by a groove  1518 . The axial portions  1514 ,  1516  are sized to extend into a groove  1520  provided in the outer sheath  1420 . As can be seen in  FIG. 82 , the groove  1520  has an inwardly protruding ring  1522  sized to extend into the groove  1518  in the seal  1510 . In the illustrated embodiment, the ring  1522  has an angled ramp  1524  formed thereon that permits the seal  1510  to slide over it during assembly, then lock in place. The outer sheath  1420  may be fabricated from, for example, Ultem®. 
       FIGS. 83 and 84  depict a non-limiting embodiment of a seal  1530  that may be employed between in the waveguide or proximal portion  1412  of the ultrasonic implement  1410  and the outer sheath  1420 . The seal  1530  comprises an annular member that may be fabricated from silicon or other materials such as, for example, Ultem® and is over molded or otherwise sealingly attached to the waveguide  1412  at a node “N”. The seal  1530  may have a groove  1532  therein as shown in  FIG. 83 . The outer sheath  1420  is then crimped to thereby crush the seal  1530  as shown in  FIG. 84 . The outer sheath  1420  could be crimped evenly all the way around the circumference, or it could be crimpled in discrete locations. For example, four evenly spaced (e.g., at 90 degree intervals) crimps may be employed. In such embodiments, the outer sheath  1420  may be fabricated from, for example, stainless steel. 
       FIG. 85  depicts a portion of an outer sheath  1540  that has a proximal axial portion  1542  and a distal axial section  1544  that are adapted to be interconnected together by, for example, welding, press fit, threading or snapping together. As can be seen in  FIG. 85 , the distal axial section  1544  has a groove portion  1546  sized to engage a portion of an annular seal  1550  that is over molded or otherwise sealingly installed on the waveguide or proximal portion  1412  of the ultrasonic implement  1410  at a node “N”. Thus, when attached together, the proximal axial section  1542  and distal axial section  1544  serve to trap and compress a portion of the seal  1550  therebetween. In alternative embodiments, the groove portion  1546  may be provided in the proximal axial section  1542  or each section  1542 ,  1544  may have a groove segment therein that cooperate to accommodate the annular seal  1550  therein. 
       FIG. 86  depicts a portion of an outer sheath, generally designated as  1560  that consists of two lateral halves  1562 ,  1564 . Each lateral half  1562 ,  1564  has a semi-annular groove segment  1566  formed therein. See  FIG. 87 . The semi-annular groove segments  1566  form an annular groove  1568  sized to receive an annular seal  1570  that is over molded onto or otherwise attached to the waveguide or proximal portion  1412  when the lateral halves  1562 ,  1564  are joined together to form the hollow outer sheath  1560 . By creating a two piece outer sheath  1560 , the seal  1570  could have much greater interference with the outer sheath  1560 , than it generally could have if the waveguide  1412  must be pushed down the outer sheath  1560  during the assembly process. The two outer sheath halves  1562 ,  1564  may be joined together by welding, snap fitting or other suitable methods. Thus, the seal  1570  may first be installed on the waveguide  1412 . Thereafter, the two halves  1562 ,  1564  may be brought together around the wave guide  1412  such that the seal  1570  is trapped within the groove  1568 . The halves  1562 ,  1564  are then fastened together in that position. 
       FIG. 88  depicts a non-limiting embodiment of a seal  1580  that may be employed between in the waveguide portion  1412  of the ultrasonic implement and the outer sheath  1420 . The seal  1580  comprises an annular member that may be fabricated from silicon or other materials such as, for example, Ultem® and is over molded or otherwise sealingly attached to the waveguide or proximal portion  1412  at a node “N”. The seal  1580  may be held in place by a proximal ring  1590  and a distal ring  1592 . The proximal ring  1590  may comprise an integral portion of the outer sheath  1420  or it could comprise a separate component that is pressed into the outer sheath  1420  or otherwise attached thereto. The distal ring  1592  may be glued, press fit or otherwise attached to the outer sheath  1420 . The distal ring  1592 , upon installation, may provide compression on the seal  1580 . This would increase the force between the seal  1580  and the waveguide  1412 , further decreasing fluid movement past the seal  1580 . The rings  1590 ,  1592  may comprise split annular rings or rings with no splits therein. In addition, as can be seen in  FIG. 88  the tings  1590 ,  1592  may be sized relative to the waveguide  1412  such that an amount of clearance “C” is provided therebetween. 
       FIG. 89  depicts a non-limiting embodiment of a seal  1600  that may be employed between in the waveguide or proximal portion  1412  of an ultrasonic implement  1410  and the outer sheath  1420 . The seal  1600  comprises an annular member that may be fabricated from silicon or other materials such as, for example, Ultem® and is over molded or otherwise sealingly attached to the waveguide  1412  at a node “N”. The seal  1600  may have an outer diameter that is greater than the inner diameter of the outer sheath  1420 . The seal  1600  may further have a proximal side  1602  and a distal side  1604 . When assembled, an outer portion of the proximal side  1602  of the seal  1600  sealingly contacts the inner wall  1421  of the outer sheath  1420 . Thus, when fluid pressure “P” builds up on the distal side of the seal  1600 , the seal  1600  is further urged into sealing contact with the outer sheath  1420 , thereby creating a better seal between the waveguide  1412  and the outer sheath  1420 . 
       FIG. 90  depicts a non-limiting embodiment of a seal  1610  that may be employed between in the waveguide or proximal portion  1412  of the blade and the outer sheath  1420 . The seal  1610  comprises an annular member that may be fabricated from silicon or other materials such as, for example, Ultem® and is molded or otherwise attached to the outer sheath  1420  as shown. In this embodiment, an annular groove  1620  may be provided in the waveguide  1412  for receiving a portion of the seal  1610  therein. In alternative embodiments, no groove is provided. It will be further understood that the seals depicted in  FIGS. 79-82  may likewise be attached to the outer sheath instead of the waveguide or proximal portion of the cutting blade or implement as illustrated without departing from the spirit and scope of the various non-limiting embodiments disclosed herein and their respective equivalents. In addition, it will be further understood that the various seal embodiments described herein may be effectively employed with any of the surgical instrument embodiments described above. That is, the various non-limiting seal arrangements disclosed herein and their respective equivalent structures may be effectively employed to achieve a seal between the ultrasonic blade or waveguide and the corresponding inner sheath. In those embodiments that employ an inner sheath and an outer sheath, but do not apply a suction therebetween, the various non-limiting seal arrangements disclosed herein and their respective equivalents may also be effectively employed to achieve a substantially fluid-tight seal between the inner and outer sheaths. In yet other non-limiting embodiments, the seal may be employed between an ultrasonic blade and an outer sheath wherein the ultrasonic blade does not engage in gross-rotational motion relative to the outer sheath. In such embodiments, the seal may be rigidly attached to the ultrasonic blade and the outer sheath. In still other non-limiting embodiments, the ultrasonic blade may oscillate within the outer sheath. For example the ultrasonic blade may oscillate through a 90 degree arc (45 degrees on each side of a central axis). In such embodiments, the seal may be rigidly attached to the outer sheath and ultrasonic blade by, for example, adhesive, crimping, etc. The seal material may comprise an elastic rubber material or the like that would accommodate twisting of the seal for a range of ±45 degrees. In such embodiments, the stretch experienced by the seal may help to return the blade to a neutral position of zero degrees (in alignment with the central axis). 
     Various of the above-described embodiments employ rotating blades that serve to shear off tissue between cutting edges formed on the blade and edges of the surrounding outer sheath. While such arrangements are very effective in cutting most tissues, tough tissue, such as tendon tissue for example, can be difficult to effectively cut because it can tend to “milk” between the blade and the outer sheath. Such problem is akin to problems encountered when scissors are used to cut through a tough material such as leather, for example. In short, the scissor blades separate and the material does not get cut. This phenomenon is graphically depicted in  FIGS. 91A-D . As can be seen in those Figures, two cutting blades  1700  are employed to cut through tough tissue “T”. As the blades  1700  move inward toward the tissue “T”, the tissue “T” moves between the blades  1700  and causes them to separate. 
     In various blade and sheath embodiments disclosed herein, it may be advantageous to minimize the amount of clearance between the cutting portion of the outer sheath and the cutting edge(s) of the blades. For example, it may be desirable to maintain the amount of clearance between the cutting portion of the outer sheath and the cutting edge(s) on the blades within the range of 0.001″ to 0.005″. In other non-limiting embodiments, one cutting edge or portion is harder than the other cutting portion. For example, the cutting edge(s) on the blades may be harder than the cutting portion of the outer sheath or visa versa. The motor may then be activated with or without ultrasound to achieve a near zero clearance between the cutting edges/portion. In addition to such approaches or in place of such approaches, other embodiments may employ structure to bias at least a distal portion the blade in an “off-center” arrangement within the outer sheath while still facilitating the rotation of the blade therein. More particularly and with reference to  FIGS. 92-93 , there is shown a blade  200  of the type and construction described above, extending through an outer sheath assembly  3000 . In the depicted embodiment, the outer sheath assembly  3000  is used in connection with a surgical instrument  3001  that may be constructed in any of the manners described above to selectively apply gross rotational motion to the blade  200  as well as to selectively apply ultrasonic motion thereto. 
     In the embodiment depicted in  FIG. 93 , the blade  200  extends axially through an inner sheath  3020  that is mounted within a portion of the instrument housing  3010 . The outer sheath assembly  3000  is attached to the instrument housing  3010  and has a distal tip portion  3002  that has a window or opening  3004  therein. As discussed above, the window  3004  enables tissue to be drawn into a tip cavity  3006  formed within the distal tip portion  3002 . Suction may be applied to the tip cavity  3006  through a suction port  3007  in the distal tip portion  3002  of the outer sheath assembly  3000  that communicates with a source of suction  244 . In these embodiments, the blade  200  is somewhat flexible and may be fabricated from, for example, Titanium. In addition, the waveguide portion or proximal portion of blade  200  extends through a bushing  3030  that is mounted within the inner sheath  3020  in the location of node “N”. In various embodiments, the inner sheath  3020  may be fabricated from material that is substantially rigid and resists bending. For example, the inner sheath  3020  may be fabricated from Ultem or similar materials. The bushing  3030  may be fabricated from, for example Ultem® and be non-rotatably retained within the inner sheath  3020  by, for example, stainless steel. 
     As can be seen in  FIGS. 92A and 93 , the waveguide or proximal portion  701  of blade  200  extends through a hole  3032  in the bushing  3030 . The centerline CL-CL of the bushing hole  3032  is offset (i.e., not coaxial with) from the central axis A-A defined by the outer sheath  3000 . The bushing hole  3032  is sized relative to the proximal portion  701  of the blade  200  to permit the proximal portion  701  to rotate freely therein, yet also serves to bias the distal end portion  700  of the blade  200  off the center axis A-A of the outer sheath  3000  such that the tissue cutting distal end  705  of the blade  200  is retained in rotatable contact with the cutting edge  3005  defined by the window opening  3004 . In some embodiments, for example, the blade  200  may be biased off center a distance that can be as much as 0.030″. Because the tissue cutting distal end  705  of the blade  200  is biased in such a manner, the distal end  705  resists forces encountered when cutting tough tissue which may otherwise cause cutting edges  706  on the distal end  705  to move away from the cutting edge  3005  of the window opening  3004 . 
       FIGS. 94 and 95  illustrate another embodiment wherein a proximal portion  701  of the blade  200  coaxially extends through a bushing  3040  that may be fabricated from, for example, silastic silicone or Ultem® and be retained within the inner sheath  3020  by, for example, a slip fit. As with the above embodiment, the bushing  3040  may be located at the node “N” along the waveguide or proximal portion of the blade  200 . However, in this embodiment, the distal portion  711  (i.e., the portion of the blade  200  that extends distally from the bushing  3040 ) is bent slightly to bias the tissue cutting distal end  705  of the blade  200  into the cutting edge  3005  of the window opening  3004 . For example, the distal portion  711  of the blade  200  may be bent approximately 0.030 inches off-center (distance OS in  FIG. 95 ). Such arrangement causes the tissue cutting distal end  705  of the blade  200  to resist forces when cutting tough tissue which may otherwise cause cutting edges  706  on the blade  200  to move away from the cutting edge  3005  of the window opening  3004 . 
       FIGS. 96-97  depict another non-limiting outer sheath  3040  and blade  200  embodiment. In this embodiment, a distal outer sheath tip  3050  is employed. The distal outer sheath tip  3050  may be fabricated from metal such as, for example, stainless steel and have a proximal bearing portion  3052  that extends into an open distal end  3062  of the outer sheath  3060 . The outer sheath  3060  may be fabricated from, for example, stainless steel and may be attached to the distal outer sheath tip  3050  by fasteners, adhesive, etc. The proximal end  3062  of the outer sheath  3060  is attached to a portion of an instrument housing as was described above. The instrument may comprise many of the various instrument embodiments described in detail above that supplies gross rotational motion to the blade  200  as well as ultrasonic motions thereto. 
     The waveguide or proximal portion  701  of the blade  200  may be attached to an ultrasonic horn (not shown) and extend through an inner sheath  3070  in the various manners described above. The proximal portion  701  of the blade  200  may be rotatably supported within the inner sheath  3070  by a bushing  3040  as was described above. A distal portion  711  of the blade  200  rotatably extends through a lumen  3054  in the distal outer sheath tip  3050 . See  FIG. 97 . A window  3056  is formed in the distal outer sheath tip  3050  to expose the tissue cutting distal end  705  of the blade  200 . As with various embodiments described above, the window  3056  may define at least one cutting edge  3057  that interacts with the rotating tissue cutting distal end  705  of blade  200  to cut tissue drawn into the window  3056 . In this embodiment, the outer diameter “OD” of the tissue cutting distal end portion  705  of the blade  200  at the point wherein the distal end  705  of the blade  200  protrudes distally into the window opening  3056  is greater than the inner diameter “ID” of the lumen  3054 . In some embodiments, for example, the inner lumen diameter “ID” may be approximately 0.140″ and the blade “OD” may be approximately 0.150″. Such arrangement results in an interference between the tissue cutting distal end  705  of the blade  200  and the distal outer sheath tip  3050 . In such arrangement, the distal portion  711  of the blade  200  essentially comprises a cantilevered beam which results in the tissue cutting distal end  705  of the blade  200  being pushed downward ( FIG. 97 ) by the distal outer sheath tip  3050 . 
     In the embodiments depicted in  FIGS. 92-97 , it may be desirable to provide an amount of clearance between the distal end  3058  of the distal outer sheath tip  3050  and the curved tip portion  702  of the blade  200 . This clearance “C” is illustrated in  FIG. 97 . Such clearance allows unimpeded ultrasonic motion of the blade  200 . However, it may be desirable to minimize such clearance “C” to reduce suction loses around the curved tip portion  702  which may hamper the device&#39;s ability to cut tissue. 
     Also, to facilitate the drawing of tissue into the window opening  3056 , suction must be applied within the distal outer sheath tip  3050  from a source of suction (not shown) in the various manners described above. In this embodiment, for example, a suction path  3080  is provided in the distal outer sheath tip  3050  as shown in  FIGS. 97 and 98 . A seal  3090  is journaled on the distal portion  711  of the blade  200  to establish a fluid tight seal at a point wherein the distal portion  711  of the blade  200  exits the inner sheath  3070 . See  FIG. 97 . Also in this embodiment, the distal end  3072  of the inner sheath  2070  extends into an opening  3055  in the bearing portion  3052  of the distal outer sheath tip  3050  to provide relative rigid support thereto. As can be seen in  FIG. 98 , the suction path  3080  forms a discontinuity in the inner sheath support surface  3057  defined by opening  3055 .  FIG. 99  depicts an alternative distal outer sheath tip  3050 ′ wherein the suction path  3080 ′ does not extend into the opening  3055 ′ that supports the distal end  3072  of the inner sheath  3070 . 
     Various ultrasonic surgical instruments that employ an outer sheath and rotatable cutting member arrangement also face the challenge of outer sheath and blade deformation due to heat and high contact forces between those two components. Deformation of the distal tip portion of the outer sheath can be reduced by changing the tip material to metal, but this can result in the undesirable effect of damaging the blade via galling, which can ultimately result in broken blades and extremely limited blade life. Such sheath tip blade galling damage can occur due to metal-to-metal contact between the blade and the sheath tip. This condition may be exacerbated when cutting tough tissues such as tendon and the like. As was discussed above, such tough tissues may bias the cutting edges away from each other and force the opposite cutting edge or face of the blade into contact with the sheath tip, thereby resulting in galling. 
     Various non-limiting embodiments described herein and their respective equivalents may employ a thin friction-reducing material on the inner wall of the tip cavity formed within the distal tip portion of the outer sheath or, in alternative embodiments, a low friction or friction reducing pad may be affixed within the tip cavity to protect the blade. One exemplary embodiment is depicted in  FIGS. 100 and 101 . As can be seen in those Figures, the outer sheath  900 ′ that was described above has a friction-reducing polymeric coating or pad  3100  therein. In various embodiments, the distal tip portion  902 ′ of the sheath  900 ′ may be fabricated from metal such as stainless steel and the friction reducing material or pad  3100  may be fabricated from, for example, polyimide, carbon-filled polyimide, Teflon®, Teflon-Ceramic, etc. In those embodiments in which a pad is employed, the pad may be affixed within the tip portion  902 ′ by, for example, adhesive or a dovetail joint arrangement. The pad  3100  is preferably configured to match the corresponding geometry of the blade. For example, as shown in  FIG. 101 , a blade  3110  that may be substantially similar to blade  200  described above, has a distal end portion  3112  that has a central portion  3114  that separates two cutting faces  3116 ,  3118 . The cutting faces  3116 ,  3118  have an arcuate shape and have cutting edges  3120  formed on each edge thereof. In that embodiment, the polymeric pad  3100  also has a similar arcuately shaped upper surface  3101 . The advantage of this concept is that it maintains a hard metallic cutting edge (e.g., stainless steel), which is advantageous for cutting tough tissue. It also protects the broad cutting faces  3116 ,  3118  of the blade  200  when the pad  3100  is fabricated from softer materials that can otherwise support the forces applied to the blade. In addition or in the alternative, the inner wall  903 ′ of the tip portion  902 ′ may be coated with a friction-reducing coating  3130  of the type described above. The coating  3130  may comprise a separate component that is held in place via adhesive or it may comprise a deposition coating that is directly adhered to the inner surface  903 ′ of the tip portion  902 ′. For example, a Teflon® material may be applied to portions of the inner wall  903 ′ through vapor deposition. The portions of the tip  902 ′ wherein the coating is not needed may be masked off using known masking techniques before exposing the tip  902 ′ to the vapor deposition process. 
       FIG. 102  depicts a tissue cutting blade end  3112 ′ that may be coated with a relatively hard, low-friction material to increase surface hardness and reduce friction. In particular, as can be seen in that Figure, at least portions of the cutting faces  3116 ′,  3118 ′ are coated with the coating material  3130 . In some embodiments, for example, the coating material may comprise coating materials such as Titanium Nitride, Diamond-Like coating, Chromium Nitride, Graphit iC™, etc. The blade  3060 ′ may be employed in connection with an outer sheath tip that is fabricated from metal (e.g., stainless steel) in order to avoid blade galling and eventual blade breakage. In alternative embodiments, the entire distal tissue cutting end of the blade may be coated with the coating material  3130 . 
     The devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the device can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the device can be disassembled, and any number of the particular pieces or parts of the device can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the device can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application. 
     Preferably, the various embodiments described herein will be processed before surgery. First, a new or used instrument is obtained and if necessary cleaned. The instrument can then be sterilized. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and instrument are then placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation kills bacteria on the instrument and in the container. The sterilized instrument can then be stored in the sterile container. The sealed container keeps the instrument sterile until it is opened in the medical facility. Sterilization can also be done by any number of ways known to those skilled in the art including beta or gamma radiation, ethylene oxide, and/or steam. 
     In various embodiments, an ultrasonic surgical instrument can be supplied to a surgeon with a waveguide and/or end effector already operably coupled with a transducer of the surgical instrument. In at least one such embodiment, the surgeon, or other clinician, can remove the ultrasonic surgical instrument from a sterilized package, plug the ultrasonic instrument into a generator, as outlined above, and use the ultrasonic instrument during a surgical procedure. Such a system can obviate the need for a surgeon, or other clinician, to assemble a waveguide and/or end effector to the ultrasonic surgical instrument. After the ultrasonic surgical instrument has been used, the surgeon, or other clinician, can place the ultrasonic instrument into a sealable package, wherein the package can be transported to a sterilization facility. At the sterilization facility, the ultrasonic instrument can be disinfected, wherein any expended parts can be discarded and replaced while any reusable parts can be sterilized and used once again. Thereafter, the ultrasonic instrument can be reassembled, tested, placed into a sterile package, and/or sterilized after being placed into a package. Once sterilized, the reprocessed ultrasonic surgical instrument can be used once again. 
     Although various embodiments have been described herein, many modifications and variations to those embodiments may be implemented. For example, different types of end effectors may be employed. Also, where materials are disclosed for certain components, other materials may be used. The foregoing description and following claims are intended to cover all such modification and variations. 
     All of the above U.S. Patents and U.S. Patent applications, and published U.S. Patent Applications referred to in this specification are incorporated herein by reference in their entirety, but only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.