Tissue liquefaction and aspiration for dental treatment

#The present invention is directed toward a method for liquefying target tissue within a body and more particularly, toward a method of heating a biocompatible fluid and presenting such to target tissue, thereby liquefying the target tissue and aspirating it while leaving non-target tissue intact.

#Prior thermal energy sources used in surgery have been “dry-heat” devices. Some examples are: thermal lasers, ultrasound, microwave, radio frequency, and electrosurgery devices. These dry-heat energy sources transfer heat from a surgical instrument to a tissue primarily by the heat transfer modalities of conduction and radiation. Thermal lasers, ultrasound, and microwave energy sources can liquefy tissue, but only at very high energy levels. If any of these dry-heat energy sources are placed in direct contact with target surgical tissue, there is no tissue differentiation. That is, healthy as well as unhealthy tissue will be liquefied. For example, collapsing cavitation bubbles in front of an ultrasound surgical instrument release a thermal energy of 13,000° F. per bubble. With such a high thermal energy input there is no differentiation of tissue within the surgical tissue field. That is, all tissue target and non-target, within the target field melts or liquefies. The thermal energy in thermal lasers and ultrasound is inherently high, so the heat cannot be “turned down” or reduced. In microwave, radio frequency, and electrosurgery the level of thermal energy may be reduced but in so doing, liquefaction of tissue is not achieved at all. Rather, cauterization or coagulation of the tissue results.

#U.S. Pat. No. 4,924,863 discloses a method for removing artherosclerotic plaque from a patient by heating the plaque under pressure for a limited period of time. When the plaque is heated, it liquefies without causing immediate death of the underlying tissue. The liquefied plaque is then aspirated from the body through a catheter. The means used for heating the plaque is microwave or radio frequency energy. As discussed above, however, in an effort to control the level of energy being produced, all of the plaque may not liquefy.

#For the purpose of illustrating the invention, there is shown in the accompanying drawing one form which is presently preferred; it being understood that the invention is not intended to be limited to the precise arrangements and instrumentalities shown.

#The sole FIGURE is an elevational view of a liquefaction and aspiration device of the present invention.

#Referring now to the drawing in detail, there is shown in the FIGURE a liquefaction and aspiration device constructed in accordance with the principles of the present invention and designated generally as 10.

#The liquefaction device 10 includes a hollow handpiece 12 with a first end 14 and a second end 16. An elongated cannula 18 extends from the first end 14 of the handpiece 12 and terminates in a tip 20. The tip 20 has three ports formed therethrough. Three lumens 22, 24, and 26 are positioned in the cannula. Each of the lumens has one end communicating with a corresponding port and an opposite end extending into the handpiece 12.

#An irrigation tube 28 has one end thereof connected to the lumen 24 and an opposite end connected to a fluid source 30. The fluid source is heated by a heating element (not shown) that can be located within or outside of the handpiece 12. The heated fluid source 30 supplies heated fluid through the heated irrigation tube 28 and out of the tip 20 of the cannula 18 via the port associated with the lumen 24. A variety of solutions that are compatible with the tissue being treated can be utilized. However, a preferred heated fluid is a saline solution. The saline solution is heated to a temperature between 98.6° F. and 250° F. This temperature defines the minimum threshold temperature of the liquid that is required to cause liquefaction of a specific substance when the heated liquid is presented to the specific substance. The heated fluid can be fed utilizing a pump mechanism or simply by the force of gravity.