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 Application 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 Application 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 general aspect, various embodiments are directed to systems and methods for controlling a surgical instrument. The surgical instrument may comprise an ultrasonic transducer, a blade extending distally from the ultrasonic transducer along a longitudinal axis, and a motor coupled to the ultrasonic transducer. The motor, when activated, may rotate the ultrasonic transducer and the blade about the longitudinal axis. A control system may receive an indication to operate the surgical instrument according to an ultrasonic-only mode. The control system may instruct the motor to rotate the blade to a park position, and activate the ultrasonic transducer to longitudinally vibrate the blade.

