Endoscope for use with a disposable sheath

[54] ENDOSCOPE FOR USE WITH A DISPOSABLE SHEATH

[75] Inventors: Eric A. Opie, Brier, by Elizabeth J.

Terry, executrix; Fred E. Silverstein,

Seattle, both of Wash. [73] Assignee: OpieLab, Inc., Seattle, Wash.

[21] Appl. No.: 185,116

[22] Filed: Apr. 22, 1988

[51] Int. Q.* A61B1/00

[52] U.S. CI 128/6

[58] Field of Search 128/4, 5, 6, 7

[56] References Cited

U.S. PATENT DOCUMENTS

2,797,683 7/1957 Aiken 128/6

3,739,770 6/1973 Mori 128/6

4,024,858 5/1977 Chikama 128/4

4,606,330 8/1986 Bonnet 128/7

4,646,722 3/1987 Silverstein et al 128/4

Primary Examiner—William H. Grieb

Attorney, Agent, or Firm—Seed and Berry

[57] ABSTRACT

An endoscope specially adapted for use with a disposable sheath having an outer casing and one or more internal channels. The endoscope includes a tip portion connected to a control handle through a flexible insertion tube. The insertion tube is formed by a braided wire tube covered by a flexible waterproof coating and surrounding a resilient D-shaped tube through which optical components for the endoscope extend. A longitudinally extending groove is formed in the braided tube to receive the channel(s). The groove extends perpendicular to, and makes contact with, a generally planar portion of the D-shaped tube so that the D-shaped tube can restrict deformation of the groove as the insertion tube bends. Longitudinal channels are formed on opposite sides of the groove to house control cables extending from the control handle to the tip portion. The cables are surrounded by tubes that collectively occupy the entire channel so that the tubes prevent the channel, and hence the groove, from collapsing.

24 Claims, 2 Drawing Sheets

10

ENDOSCOPE FOR USE WITH A DISPOSABLE
SHEATH

TECHNICAL FIELD

This invention relates to the field of endoscopy, and more particularly, to the construction of the basic endoscope core of a device for inexpensively isolating an endoscope from virus and bacteria.

BACKGROUND ART

The use of endoscopes for diagnostic and therapeutic indications is rapidly expanding. To improve performance, endoscopes have been optimized to best accomplish their purpose. Therefore, there are upper endo- 15 scopes for examination of the esophagus, stomach and duodenum; colonoscopes for examining the colon; angioscopes for examining blood vessels; bronchoscopes for examining the bronchi; laparoscopes for examining the peritoneal cavity; and arthroscopes for examining joint 20 spaces. The discussion which follows will apply to all of these types of endoscopes.

Instruments to examine the rectum and sigmoid colon, known as "flexible sigmoidoscopes," are good examples of the usefulness of endoscopic technology. 25 These devices are expensive, and they are used in a contaminated environment for a procedure which is brief (five to ten minutes) and where problems of cleaning time and contamination are important factors. There has been a large increase in the use of the flexible sig- 30 moidoscope for use in screening symptomatic and asymptomatic patients for colon and rectal cancer. Ideally, flexible sigmoidoscopes must be used rapidly and inexpensively in order to maintain the cost of such screening at acceptable levels. Typically, a clinic would 35 like to perform five sigmoidoscope examinations each hour. A significant problem with making such examinations quick and inexpensive is the time necessary for adequately cleaning the device.

Although endoscopes can be cleaned in about two to 40 four minutes, this relatively cursory cleaning may not be adequate for complete disinfection or sterilization. Even a more complete cleaning, requiring on the order of eight to ten minutes, may not allow adequate cleaning, particularly in view of the increasing problems with 45 contagious viruses. Even with the use of chemicals such as gluteraldehyde, adequate cleanliness may not be possible.

The cleaning problem not only includes the outside of the endoscope, but also the multiple small channels 50 inside the endoscope. This includes channels for: air insufflation; water to wash the tip; and biopsy and suction. Each channel also has a control valve. These channels extend along the length of the endoscope and come into contact with body tissues and fluids. It is extremely 55 difficult to adequately clean these channels even when skilled health practitioners spend a great deal of time on the cleaning procedure.

Even if endoscopes can be adequately cleaned in eight to ten minutes, the cleaning still prevents endos- 60 copy examinations from being relatively inexpensive. While a physician may spend five to ten minutes performing some types of endoscopy, he or she will generally waste a great deal of time waiting for the endoscope to be cleaned before he or she can conduct another 65 endoscopy. A partial solution to the "idle time" problem is to purchase multiple instruments so one can be used as the others are being cleaned. However, the

expense of having duplicate endoscopes of each of the many types described above makes this solution impractical especially for physicians' offices and smaller clinics.

Not only must the idle time of the physician be added to the cost of endoscopic examinations, but the time spent by a nurse or other hospital personnel in the cleaning as well as the cost of disinfecting chemicals and other costs of the cleaning process must also be added to the cost of the examination. Although automatic washing machines are available to clean endoscopes, these machines are expensive, take up significant amounts of space, are noisy, and are not faster than washing by hand. Further, regardless of whether the cleaning is done manually or by machine, the cleaning chemicals can be harmful to the endoscope and thus significantly shorten its life. The cleaning chemicals, being toxic, are also potentially injurious to the staff who use them and to the environment into which they are discharged. To use some of these chemicals safely, such as gluteraldehyde, requires a dedicated ventilated hood, which uses up space and is expensive to install and operate. The chemicals are also potentially toxic to the patient in that, if residue remains after cleaning and rinsing the instrument, the patient could have a reaction to the chemicals.

As a result of these many problems, conventional endoscope cleaning techniques greatly increase the cost of endoscopic procedures. Furthermore, while the risk of contamination using endoscopes is often far less than the risk of alternative procedures, such as surgery, there is nevertheless a risk that endoscopes are not cleaned adequately to prevent the risk of transmission of infectious diseases from one patient to the next.

In the health care field, the problem of contaminated instruments transmitting disease from one patient to the next have generally been solved by making such instruments disposable. However, this approach has not been thought possible in the field of endoscopy because endoscopes are very expensive instruments. Moreover, it has not been thought possible to isolate the endoscope from the patient or the external environment because the endoscope itself has channels inside it that are used as conduits for body fluids and tissues, such as, for example, in taking biopsies. The only method currently available to actually sterilize an endoscope is to use gas sterilization with ethylene oxide gas. However, there are several disadvantages in using this procedure. The procedure is very slow (up to 24 hours), during which time the endoscope cannot be used. Also, the gas affects the plastic of the endoscope and may limit its lifespan. Finally, the gas is toxic, and, therefore, great care must be taken to ensure that no residue remains that might cause patient or staff irritation or allergic reaction during contact with the endoscope.

As a result of the above-described limitations in using and cleaning endoscopes by conventional techniques, there has not heretofore been an acceptable solution to the problem of making endoscopy procedures both inexpensive and entirely safe.

A new approach to the problem of endoscope contamination is described in U.S. Pat. No. 4,646,722. This new approach involves the use of an endoscope sheath having a flexible tube surrounding the elongated core of an endoscope. The flexible tube has a transparent window near its distal end positioned in front of the viewing window of the endoscope. Channels that come into