Patent Application
20100145258
1. Field
The present disclosure is directed to systems and methods for eliminating post-excitation vibration in ophthalmic surgical handpieces.
2. Description of the Related Art
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In eye surgery, particularly phacoemulsification (phaco) surgery, ultrasonic vibration is commonly used to emulsify tissue within an eye of a patient. Ultrasonic vibration is often provided by a stack of crystals included in a surgical handpiece having a needle connected thereto. Initially, an operator inserts the needle into patient's eye. By applying a voltage to the crystals, in response to an operator request, ultrasonic vibration is produced. The ultrasonic vibration is delivered to an eye through the needle. When an operator no longer requests ultrasonic vibration, the voltage is removed from the surgical handpiece, and specifically, the crystals. When the voltage is removed, the crystals continue to vibrate for an interval, commonly understood as a “ring-down” interval of the crystals. During the “ring-down” interval, the needle, which remains inserted in the eye, continues to deliver ultrasonic vibration to the patient's eye. In some instances, a period between multiple applications of voltage to the crystals may be less than the “ring-down” interval, such that the crystal constantly vibrates the needle irrespective of request from the operator.
In order to minimize an amount of ultrasonic vibration delivered to an eye during ophthalmic surgery, it is desirable to provide vibration to the patient's eye only when requested by an operator of a surgical handpiece.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.
According to one exemplary embodiment of the present disclosure, a method 100 of eliminating post-excitation vibration provided from a surgical handpiece to a patient's eye during ophthalmic surgery is illustrated in
By utilizing a brake signal to eliminate vibration of the needle after ceasing excitation, method 100 allows the operator to minimize the amount of vibration transmitted to the patient's eye over an entire ophthalmic surgery and to apply ultrasonic energy to the eye only when desired. In one example, during a phacoemulsification procedure, an operator may excite a crystal structure to cause ultrasonic vibration multiples times during an ophthalmic surgery, and therefore, also cease excitation of the crystal structure multiples times in the ophthalmic surgery. Over the ophthalmic surgery, the amount of ultrasonic vibration transmitted to the patient's eye during “ring-down” may be eliminated by generating a brake signal according to the present disclosure for each of the multiple cessations of excitation of the crystal structure.
The method illustrated in
The ophthalmic surgery system 200 includes a surgical handpiece 202 and a control circuit 204, which is electrically coupled to the surgical handpiece 202 via cable 206 The surgical handpiece 202 includes an ultrasonic vibration structure 208, a needle 210, and a horn 212. The ultrasonic vibration structure 208 will be illustrated in this example as a crystal structure 208, but other structures may be used The crystal structure 208 is in mechanical communication with the needle 210 through the horn 212. In this particular embodiment, the crystal structure includes two piezoelectric crystals. It should be appreciated that a different number and type of crystals may be employed in other embodiments of the present disclosure, as well as a magneto-resistive structure well known in the phaco arts.
In use during ophthalmic surgery, an operator grips the surgical handpiece 202 and inserts the needle 210 into a patients' eye (not shown) for emulsifying tissue. The operator generally uses a foot pedal for indicating an operator demand for ultrasonic vibration of the needle 210. When the operator demand is received by the control circuit 204, the control circuit 204 is configured to provide an excitation signal, via cable 206, to the crystal structure 208 included in the surgical handpiece 202. The excitation signal causes ultrasonic vibration of the crystal structure 208. Vibration of the crystal structure 208, in turn, causes ultrasonic vibration of the horn 212 and the needle 210. When the operator no longer desires ultrasonic vibration at the patient's eye, the operator steps off the foot pedal, indicating to the control circuit 204 to cease ultrasonic vibration to the patient's eye. In response, the control circuit 204 ceases outputting the excitation signal to the crystal structure 208.
Upon ceasing the excitation signal to the crystal structure 208, the control circuit 204 is configured to provide a brake signal to the surgical handpiece 202. In this manner, the brake signal is applied substantially immediately after the excitation signal ceases. The brake signal eliminates ultrasonic vibration of the needle 210 within the patient's eye, after the cessation of the excitation signal, which generally reduces a total amount of ultrasonic vibration transmitted to the patient's eye during an ophthalmic surgery.
According to at least the embodiment of
Further, since the brake signal 304 is out-of-phase from the excitation signal 306, one or more types of energy generated in the surgical handpiece 202 may be prevented by the control circuit 204, potentially resulting in reduced heat generation in the surgical handpiece 202.
In this particular embodiment, the brake signal 304 is about 180 degrees out-of-phase from the excitation signal 302. In other embodiments, other phase-shifts may be employed to eliminate or reduce the vibration of a crystal structure, horn and/or needle after excitation of the crystal structure has ceased. For example, a phase-shift between about 90 degrees and about 270 degrees may be effective to reduce and/or eliminate vibration transmitted to the patient's eye after excitation is ceased. It should be appreciated that various magnitudes and/or frequencies for one or both of an excitation signal and a brake signal may be employed in other embodiments of the present disclosure, depending on safety of the patient, effectiveness of a surgical handpiece, operation of a surgical handpiece, components of a surgical handpiece, type of ophthalmic surgery, etc. Further, a magnitude and/or a frequency of an excitation signal may be different than that of a brake signal. For example, a magnitude of a brake signal may be greater than a magnitude of an excitation signal to increase an opposing force to a crystal structure upon cessation of the excitation signal.
While the excitation signal 302 and brake signal 304 are illustrated as having a sinusoidal waveform in
The brake signal 304 may be provided to the crystal structure 208 for a fixed time interval sufficient to eliminate vibration of the crystal structure 208 and needle 210. In the particular embodiment of
According to at least one embodiment, a brake signal may be applied after elimination of vibration of a crystal structure and/or a needle such that the crystal structure vibrates according to one or more unique types of patterns. For example, applying a brake signal beyond rest of a crystal structure and/or a needle may result in approximately triangular or sinusoidal amplitude modulated vibration of the needle. Various types, amplitudes, and forms of unique pulsing of a crystal structure may be implemented, depending on requirements of one or more components included in an ophthalmic surgery system and/or an operator.
According to one exemplary embodiment of the present disclosure, an ophthalmic surgery system 400 is illustrated in
The brake mechanism 412 included in the surgical handpiece 402 includes a piezoelectric crystal. It should, however, be appreciated that a brake mechanism may include a different type of crystal and/or mechanical actuator suitable for contacting at least one of a horn, a needle, or a different components of a surgical handpiece to eliminate vibration of the needle included in the surgical handpiece.
Although several aspects of the present disclosure have been described above with reference to phacoemulsification instruments, it should be understood that various aspects of the present disclosure are not limited to phacoemulsification instruments, and can be applied to a variety of other ophthalmic surgical procedures.
By implementing any or all of the teachings described above, a number of benefits and advantages can be attained including improved reliability, reduced down time, elimination or reduction of redundant components or systems, avoiding unnecessary or premature replacement of components or systems, and a reduction in overall system and operating costs.
