Fluid-Assisted Medical Devices, Fluid Delivery Systems and Controllers for Such Devices, and Methods

Abstract

Medical devices, methods and systems for treating tissue are provided. An exemplary system comprises a fluid from a fluid source, a surgical device which provides energy and the fluid to the tissue and a control mechanism which changes a flow rate of fluid provided from the surgical device and changes a rate of energy provided from the surgical device. The fluid flow rate changes between at least two non-zero flow rates and the energy rate changes between at least two non-zero energy rates. An exemplary method comprises providing a fluid from a fluid source, providing a surgical device which provides energy and the fluid to the tissue, and changing a flow rate of fluid provided from the surgical device with a change in a rate of energy provided from the surgical device. Exemplary devices comprise a tip portion configured to provide energy and a fluid to a tissue.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This patent application is a continuation of U.S. Ser. No. 09 / 947,658 filed Sep. 5, 2001, now U.S. Pat. No. ______, which is a continuation-in-part of U.S. Ser. No. 09 / 797,049, filed Mar. 1, 2001, now pending, the entire disclosure of which is incorporated by reference, which claims priority to U.S. Ser. No. 60 / 187,114, filed Mar. 6, 2000, the entire disclosure of which is incorporated herein by reference.FIELD OF THE INVENTION [0002] This invention relates generally to the field of medical devices, methods and systems for use upon a body during surgery. More particularly, the invention relates to electrosurgical devices, methods and systems for use upon tissues of a human body during surgery. BACKGROUND [0003] Electrosurgical devices use electrical energy, most commonly radio frequency (RF) energy, to cut tissue or to cauterize blood vessels. During use, a voltage gradient is created at the tip of the device, thereby inducing current f...

AI Technical Summary

Benefits of technology

[0018] The invention can improve the speed of tissue coagulation provided by fluid-enhanced electrosurgery by assuring that the electrode-tissue interface is within a desired temperature range (for example, not significantly hotter than 100° C.) through the control of the fraction of conductive fluid that is boiled off at the electrode-tissue interface. This improvement can be achieved by measuring power provided to the device and regulating the flow of fluid to the device. Preferably, tissue sensors (for example, that would measure tissue temperature or tissue impedance) are not required according to the invention.

[0019] Some embodiments of the invention can provide one or more advantages, such as the ability to achieve the desired tissue effect (for example, coagulation, cutting, or the like) in a fast, effective manner. The invention can also provide the ability to treat tissue quickly without using a tissue sensor (for example, a temperature sensor) built into the device or a custom special-purpose generator. The invention can allow a surgeon to use a variety of electrosurgical devices with a wide variety of general-purpose generators. Further, the invention can provide the ability to use an electrosurgical device that is capable of quickly and effectively sealing a wide variety of tissue sizes and thicknesses.

[0024] In some applications of the techniques described herein, the fluid flow control mechanism increases the flow rate of fluid provided from the surgical device with an increase in a boiling percentage of the fluid provided from the surgical device. Alternately or additionally, the fluid flow control mechanism decreases the flow rate of fluid with a decrease in the boiling percentage of the fluid.

Problems solved by technology

Current electrosurgical devices can cause the temperature of tissue being treated to rise significantly higher than 100° C., resulting in tissue desiccation, tissue sticking to the electrodes, tissue perforation, char formation and smoke generation.

Undesirable results of such transmission to adjacent tissue include unintended thermal damage to the tissue.

However, an uncontrolled flow rate of saline can provide too much cooling at the electrode / tissue interface.

This, in turn, can result in longer treatment time, to achieve the desired tissue temperature for cauterization or cutting of the tissue.

Long treatment times are undesirable for surgeons since it is in the best interest of the patient, physician and hospital to perform surgical procedures as quickly as possible.

RF energy delivered to tissue is unpredictable and often not optimal when using general-purpose generators.

A further limitation of current electrosurgical devices arises from size constraints of the device in comparison to tissue that is encountered during a single surgical procedure.

Surgical devices often come in a variety of sizes because larger segments of tissue physically require commensurately larger electrode jaws or tips, but smaller segments of tissue often are not optimally treated by the much larger size RF device.

It is undesirable to require numerous surgical devices during a single procedure, because this wastes valuable operating room time, can make it difficult to precisely relocate the treatment site, increases the risk of infection, and increases the cost by increasing the number of different surgical devices that are needed to complete the surgical procedure.

For example, a bipolar saline-enhanced tissue sealing forceps that has jaws long enough to effectively seal a 30 mm length of tissue may not be desirable for sealing a segment of tissue that is 10 mm in length.

For at least the reasons identified above, this is an undesirable situation with current electrosurgical devices.

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