1. Technical Field of the Invention
This invention relates to instrument heaters, and more particularly, to an apparatus for heating a instrument used in surgery, such as laparoscopic surgery.
2. Description of Related Art
Various delicate and small instruments are used in surgery. One of the most important instruments utilized by surgeons is an optical scope. An optical scope is essentially a telescope which normally has a camera for inserting through a small incision into a human body to view the interior of the body, such as the stomach. The optical scope includes a long thin cylindrical probe having a lens at one end and a fiber optic line that connects a camera to the lens. Wires connect the camera to a display used for viewing by a surgeon. The long thin portion of the probe is small enough and long enough to enter through the small incision. The use of the optical scope provides a very useful means for viewing the interior of the human body, without opening the cavity of a body to major surgery (e.g., large incisions).
Although the optical probe is very useful in surgery, there is a problem associated with using the optical scope. When the optical scope is initially inserted through the small incision into the interior of the body, the lens at the tip of the optical scope fogs up. The optical scope's lens fogs up because of the differential in temperature between the initial temperature of the probe and the interior of the human body. The optical scope is much cooler than the warm and moist interior of the human body. This temperature differential produces a moist film on the lens of the optical scope, resulting in the clouding of the lens.
When the lens fogs up, a surgeon must wait several minutes, with the optical scope being inserted into the interior of the body, until the temperature of the optical scope is equalized with the temperature of the interior of the body. This is a waste of precious time and prolongs the length of the surgery. Therefore, a simple, safe, sterile and inexpensive method and apparatus is needed to prevent the lens of the optical scope from fogging up. The present invention provides such a device.
One known prior art teaching of a solution to the aforementioned deficiency and shortcoming is to coat the lens of the optical scope with an anti-fogging material prior to inserting the scope into the incision. To date, the results from this prior art technique have been marginal at best. Other prior art references that discuss subject matter that bears some relation to matters discussed herein are U.S. Pat. No. 5,207,213 to Auhll et al. (Auhll), U.S. Pat. No. 4,279,246 to Chikama (Chikama), U.S. Pat. No. 5,400,767 to Murdoch (Murdoch), U.S. Pat. No. 5,549,543 to Kim (Kim), and U.S. Pat. No. 5,647,840 to D'Amelio et al. (D'Amelio).
Auhll discloses a laparoscope for performing laparoscopic surgery. The laparoscope includes a rigid elongated sheath tube having a distal section and a proximal section. The distal section has a distal tip with a lens. The lens has an exterior surface located at the distal tip. The laparoscope includes a fluid flow channel which terminates in a nozzle located at the distal tip for directing a fluid flow across the exterior surface of the lens. The laparoscope further includes a first channel which terminates in an orifice which is capable of directing a flow of irrigation fluid along a selected path. Auhll does not teach or suggest a simple method for preventing the formation of moisture film on the lens of an optical scope. Auhll merely discloses a complicated apparatus for removing the moisture film by directing a fluid over the optical scope.
Chikama disclose a device for preventing the clouding of an observing window of an optical scope using heat rays from a light source. A converter is provided for changing light into heat and transmitting optical bundles. A portion of the light is changed into heat by the converter causing the observing window to be warmed, thereby preventing the clouding. Although Chikama discloses a method and apparatus for heating the lens of an optical scope. Chikama does not use a simple, disposable sheath to warm the optical scope. Chikama utilizes a complicated device having a light source, to generate the necessary heat. Murdoch discloses a device for cleaning the lens of an optical scope within removing the scope from the body cavity. The device includes a tube, an inner diameter of the tube accepting the shaft of the optical scope. On the inner circumference, near to or at one end of the tube, is a ridge that can direct a flow of fluid within the tube onto the lens of the optical scope. During operation, whenever the lens becomes obscured, a fluid is injected into the device to clean the lens. Murdoch does not teach or suggest a device to prevent the formation of a moisture film on the lens of the optical scope. Murdoch merely discloses a device to remove a film obscuring the lens of the optical scope.
Kim discloses a laparoscopic defogging apparatus used to regulate and maintain the temperature of a lens at an end portion of the laparoscope. The apparatus utilizes a receptacle containing a first sterile fluid in which the lens is placed within. Additionally, a container is provided into which the receptacle is placed, the container being adapted to receive and contain a second sterile fluid at a sufficient depth to provide thermal contact with at least a part of the receptacle side wall portion. Kim also includes a heating device which provides heat to the sterile fluids whereby the laparoscope is maintained at a constant desired temperature. Although Kim discloses a device which warms the lens of an optical scope, Kim does not teach or suggest a simple method for heating the lens. Rather, Kim utilizes a complicated device using fluids to maintain the lens of the optical scope at the desired temperature.
D'Amelio discloses an endoscope having a distally heated lens for performing laparoscopic surgery. The laparoscope includes a rigid elongated sheath tube which encloses means defining a fiber optic light caring bundle. The fiber optic bundle has a proximal end which is adapted to be operatively coupled to a light source having light energy including infrared radiation and a distal end which is located in the distal section of the sheath tube contiguous the distal lens. The lens is heated by the light source. D'Amelio does not teach or suggest a device which can be simply and effectively used on an existing optical scope. D'Amelio merely discloses designing an entirely new and more complicated optical scope to prevent the formation of an film obscuring the lens of the optical scope.
Additionally, other methods have been used to solve the problem of moisture film formation. One such method involves applying alcohol wipes to the lens prior to use within the interior of the body. However, the alcohol wipes do not prevent the formation of the moisture film. Since the alcohol is cool, the lens remains cool, resulting in the formation of the unwanted film.
Thus, it would be a distinct advantage to have a method and apparatus for heating an optical instrument to prevent the fogging of the lens of the optical instrument. It is an object of the present invention to provide such a method and apparatus.