A closed-loop control system is disclosed for use with an electrosurgical generator that generates electrosurgical energy. The closed loop control system includes a user interface for allowing a user to select at least one pre-surgical parameter, such as the type of surgical instrument operatively connected to the generator, the type of tissue and the desired surgical effect. A sensor module is also included for continually sensing at least one of electrical and physical properties proximate a surgical site and generating at least one signal relating thereto. The system also includes a control module for continually receiving the at least one selected pre-surgical parameter from the user interface and each of the signals from the sensor module, and processing each of the signals in accordance with the at least one pre-surgical parameter using at least one of a microprocessor, computer algorithm and a mapping. The control module generates at least one corresponding control signal relating to each signal from the sensor module, and relays the control signal to the electrosurgical generator for controlling the same. A method is also disclosed for performing an electrosurgical procedure at a surgical site on a patient. The method includes the steps of: applying at least one electrical pulse to the surgical site; continually sensing electrical and physical properties proximate the surgical site; and varying pulse parameters of individual pulses of the at least one pulse in accordance with the continually-sensed properties.

Method and system for controlling output of RF medical generator

Rayleigh, Brillouin and Raman scatterings in fibers result from the interaction of photons with local material characteristic features like density, temperature and strain. For example an acoustic/mechanical wave generates a dynamic density variation; such a variation may be affected by local temperature, strain, vibration and birefringence. By detecting changes in the amplitude, frequency and phase of light scattered along a fiber, one can realize a distributed fiber sensor for measuring localized temperature, strain, vibration and birefringence over lengths ranging from meters to one hundred kilometers. Such a measurement can be made in the time domain or frequency domain to resolve location information. With coherent detection of the scattered light one can observe changes in birefringence and beat length for fibers and devices. The progress on state of the art technology for sensing performance, in terms of spatial resolution and limitations on sensing length is reviewed. These distributed sensors can be used for disaster prevention in the civil structural monitoring of pipelines, bridges, dams and railroads. A sensor with centimeter spatial resolution and high precision measurement of temperature, strain, vibration and birefringence can find applications in aerospace smart structures, material processing, and the characterization of optical materials and devices.

Recent progress in distributed fiber optic sensors.

An electrosurgical system is disclosed. The electrosurgical system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue. The electrosurgical generator includes impedance sensing circuitry which measures impedance of tissue, a microprocessor configured to determine whether a tissue reaction has occurred as a function of a minimum impedance value and a predetermined rise in impedance, wherein tissue reaction corresponds to a boiling point of tissue fluid, and an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue.

Vessel sealing system

An electrosurgical system is disclosed. The electrosurgical system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue. The electrosurgical generator includes impedance sensing circuitry which measures impedance of tissue, a processor configured to determine whether a tissue reaction has occurred as a function of a minimum impedance value and a predetermined rise in impedance, wherein tissue reaction corresponds to a boiling point of tissue fluid, and an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue. A tissue cooling period is provided to enhance operative outcomes.

System and method for tissue sealing

A variety of techniques are available enabling both invasive measurement, where the monitoring device is installed in the medium of interest, and noninvasive measurement where the monitoring system observes the medium of interest remotely. In this article we review the general techniques available, as well as specific instruments for particular applications. The issues of measurement criteria including accuracy, thermal disturbance and calibration are described. Based on the relative merits of different techniques, a guide for their selection is provided.

Review of temperature measurement

If one area manifests clinically, it can be removed by Mohs surgery, but the second, noncontiguous, area may not be found during treatment, only to appear later and be considered a recurrence of the Mohs surgery. Second, human error accounts for a 5-year 99% cure rate for primary basal cell carcinomas by Mohs technique compared with the theoretically predicted 100% cure rate. With the numerous and detailed steps for excision, orientation, mapping, preparing frozen sections, and histologic interpretation of the tissue, errors are possible and may result in a recurrence. For example, if the tissue is mislabeled or mapped improperly and persistent tumor is noted microscopically, the wrong area of the wound may be reexcised. In addition, the frozen section may contain gaps or may not include the entire surface and a false-negative interpretation made, resulting in a recurrence. Fortunately, the technique includes careful routines to minimize the chance of human error.

L. Michalski

Papers

Temperature measurement