A surgical instrument. The surgical instrument may comprise a transducer and an end effector. The transducer may be configured to provide vibrations along a longitudinal axis at a predetermined frequency and may comprise a piezoelectric stack positioned along the longitudinal axis. The transducer also may comprise a first metallic end mass positioned along the longitudinal axis adjacent a first end of the piezoelectric stack and a second metallic end mass positioned along the longitudinal axis adjacent a second end of the piezoelectric stack. The length of the transducer may be greater than or equal to of one wavelength and less than ½ of one wavelength. The end effector may be coupled to the transducer and may extend along the longitudinal axis. The length of the transducer and the end effector may be a multiple of ½ of one wavelength.

Ultrasonic surgical instruments

An ultrasonic clamp coagulator assembly that is configured to permit selective cutting, coagulation and clamping of tissue during surgical procedures. An elongated portion of the instrument can be configured for endoscopic applications and has an outside diameter of less than 6 mm. The construction includes a clamping mechanism, including a clamp arm pivotally mounted at the distal portion of the instrument, which is specifically configured to create a desired level of tissue clamping forces, exceeding 4 pounds when the trigger is fully closed. The clamping mechanism includes a force-limiting mechanism that effectively smooths out abusive tissue forces.

Actuation mechanism for use with an ultrasonic surgical instrument

Various ultrasonic instruments are disclosed. The ultrasonic instruments include structures configured to indicate the cutting length of the instruments, detect when grasped tissue has extended beyond the cutting length of the instrument, and prevent tissue from extending beyond the cutting length. Several techniques for each types of structures are disclosed.

Tissue loading of a surgical instrument

An ultrasonic surgical shears includes an ultrasonic surgical blade, a clamping arm operable to open and close toward the blade, and a tissue pad attached to the clamping arm. A method for sealing a blood vessel of a patient includes obtaining an ultrasonic surgical shears and positioning the blood vessel between the blade and the tissue pad. The clamping arm is operated to exert an average coaptation pressure on the blood vessel between and including 60 psi and 210 psi. The blade is ultrasonically vibrated to transect and seal the blood vessel.

Ultrasonic surgical shears and method for sealing a blood vessel using same

A surgical instrument includes an ultrasonic transducer, an ultrasonic transmission waveguide extending from the ultrasonic transducer, and an ultrasonic blade acoustically coupled to the ultrasonic transmission waveguide. The ultrasonic blade includes a base and a curved body extending distally from the base. The curved body includes a tissue-treating surface extending on a first side of the curved body and a curved edge extending on a second side of the curved body opposite the first side. The curved edge has a proximal end and a distal end, wherein the proximal end is offset from the distal end in a first direction, wherein the proximal end is offset from the distal end in a second direction, and wherein the first direction is perpendicular to the second direction.

Ultrasonic surgical blade for use with ultrasonic surgical instruments

An ultrasonic generator circuit is described which comprises a resonant LC power oscillator circuit for driving an ultrasonic transducer, the resonant circuit comprising a voltage controlled switching element (an integrated gate bipolar transistor is preferred), and feedback being provided via a feedback transformer whose primary is connected in the resonant circuit, the secondary of the feedback transformer being connected to a feedback signal converter which, in dependence upon feedback current induced in the secondary of the feedback transformer, applied a feedback voltage to the input of the voltage controlled switching element (Fig. 6).

Ultrasonic generator circuit incorporating a power oscillator and a feedback loop

In order to supply to the transducer T DH a time varying current of constant direction, the transducer is connected via a switching means Q 1 , preferably a transistor, across a DC power supply, a capacitor C 1 being effectively connected in parallel with the transducer creating an LC circuit in which the inductance is contributed by the transducer inductance L L wholly or in combination with matching inductance L H . A control signal controls the switching means such that it opens periodically at the drive frequency required by the transducer, and may be provided by means of a transformer T X2 whose primary L E is connected to the LC circuit and whose secondary L F is led to the transistor input. The circuit achieves "zero-crossing": substantial current passes through the switching means only when substantially no voltage is present across it, whereby heat loss in the switching means is minimised.

Henry Kevin Ratcliff

Papers

Ultrasonic generator circuit incorporating a power oscillator and a feedback loop

Ultrasonic generator circuit for magnetostrictive transducer