Cordless hand-held ultrasonic cautery cutting device

An ultrasonic surgical assembly, comprising:

• an ultrasonic transducer operable to convert a received motional current into a movement of a cutting blade of an ultrasonic waveguide, the ultrasonic transducer having a first capacitance in a parallel configuration with a series configuration of a resistance, an inductance and a second capacitance, whereby the motional current flows through the series configuration;
• a third capacitance in a parallel configuration with the first capacitance;
• a variable power source coupled to the third capacitance and the ultrasonic transducer;
• and
• a current controller operable to regulate the motional current by varying an output of the variable power source based upon a product of the current flowing through the third capacitance multiplied by a ratio between a value of the first capacitance and a value of the third capacitance subtracted from a total current flowing into the ultrasonic transducer, thereby maintaining a substantially constant rate of movement of the cutting blade across a variety of cutting loads.

An ultrasonic surgical assembly, comprising:

• an ultrasonic transducer operable to convert a received motional current into a movement of a cutting blade of an ultrasonic waveguide;
• a removable battery;
• a disposable handle body having:
• a portion defining a battery-holding compartment shaped to removably receive the battery therein;
• and
• operable to removably couple the ultrasonic transducer to the ultrasonic waveguide, the ultrasonic transducer being separable from the handle body;
• the ultrasonic transducer having a first capacitance in a parallel configuration with a series configuration of a resistance, an inductance and a second capacitance, whereby the motional current flows through the series configuration;
• a third capacitance in a parallel configuration with the first capacitance;
• a variable power source coupled to the third capacitance and the ultrasonic transducer;
• and
• a current controller operable to regulate the motional current by varying an output of the variable power source based upon a product of the current flowing through the third capacitance multiplied by a ratio between a value of the first capacitance and a value of the third capacitance subtracted from a total current flowing into the ultrasonic transducer, thereby maintaining a substantially constant rate of movement of the cutting blade across a variety of cutting loads.

An ultrasonic surgical assembly, comprising:

• an ultrasonic transducer operable to convert a received motional current into a movement of a cutting blade of an ultrasonic waveguide;
• a clamping mechanism having a range of clamping force values and being operable to place material in physical contact with the cutting blade;
• a current controller communicatively coupled to the clamping mechanism and operable to vary the motional current based upon a given clamping force value within the range of clamping force values;
• a measurement circuit connected in a parallel configuration with the ultrasonic transducer;
• a variable power source operable to supply current through a set of connection points to the parallel configuration and thereby create the motional current in the ultrasonic transducer;
• and
• the current being controller operable to regulate the motional current by varying an output of the variable power source, thereby maintaining a substantially constant rate of movement of the cutting blade across a variety of cutting loads.