End-point detection method and medical device controller and treatment system with end-point detection, particularly for electrosurgery

A controller for a medical device for treating a biological tissue, the controller comprising a processor configured to:

• obtain an amount of electric power for estimating a state of the tissue;
• determine an in-process heat capacity of the biological tissue during a time period of application of applied energy to the biological tissue, wherein the applied energy is ultrasonic energy or electrical energy;
• determine a state of the biological tissue based on the in-process heat capacity;
• and
• control the medical device based on the state of the biological tissue,
• wherein the medical device includes an end-effector configured to operate on the biological tissue,
• wherein determining the in-process heat capacity of the biological tissue includes determining a ratio of energy input to the end-effector over a sampling interval to a change in temperature of the biological tissue over that sampling interval, and
• wherein the change in temperature of the biological tissue is determined by:
• estimating, based on a first set of parameters, a residual energy associated with (i) a prior amount of electrical power provided to the medical instrument, (ii) a prior amount of electrical power consumed by the medical instrument, (iii) a prior amount of electrical power applied to the end-effector, (iv) a prior amount of electrical power consumed by the end-effector, or (v) a combination thereof;
• determining, based on the first set of parameters, a change in energy of the end-effector based on (i) a current amount of electrical power provided to the medical instrument, (ii) a current amount of electrical power consumed by the medical instrument, (iii) a current amount of electrical power applied to the end-effector, (iv) a current amount of electrical power consumed by the end-effector, or (v) a combination thereof:
• estimating a residual temperature of the end-effector associated with the residual energy;
• and
• determining a change in temperature of the end-effector associated with the change in energy.