The present invention relates generally to medical probes, and specifically to endoscopes.
Various types of endoscopes are known in the art for visual inspection and diagnosis of the rectum and sigmoid of the large intestine. Rigid rectoscopes and sigmoidoscopes are most commonly used for this purpose, since they are durable, easy to use and relatively inexpensive.
To perform an examination using the rigid rectoscope (or sigmoidoscope), the physician first inserts a speculum through the anus. An obturator, having a blunt, rounded distal end, is fitted inside the speculum and protrudes distally therefrom to ease the insertion. Once the speculum is in place, the physician withdraws the obturator and closes the proximal end of the speculum with a plug. A special telescope is fitted into the plug, which enables the physician to view the inside of the rectum and sigmoid at the distal end of the speculum, either by direct vision or using a video camera coupled proximally to the telescope. In order to illuminate the area under view, a light source in an external console is coupled proximally to the speculum by fiberoptics. Typically, the plug also includes one or more working channels, which are used for irrigation, insufflation or insertion of surgical tools through the speculum.
Various rectoscopes and sigmoidoscopes of this type are available commercially. For example, Karl Storz GmbH, of Tuttlingen, Germany, offers the model 24911S rectoscope, which may be used with a rod lens telescope (for example, model 24946B) to view the rectum either under direct view or using a Karl Storz Endovision video camera. The rectoscope and accessories are made from stainless steel to allow disinfection and autoclaving between uses.
Rectoscopes and sigmoidoscopes having a disposable speculum and obturator are also available, such as the KleenSpec disposable sigmoidoscope produced by Welch Allyn Inc., of Skaneateles Falls, N.Y. The speculum and obturator are made of plastic. The speculum clips or screws onto a multi-use handle, to which a light source, telescope, video camera and instruments may be attached.
Flexible sigmoidoscopes and colonoscopes are also known in the art. Most such scopes include a fiberoptic bundle for conveying images from their distal end, within the intestine, to an eyepiece or video camera fixed to the proximal end. Some such scopes, such as the Pentax ES3801 PVE Video Sigmoidoscope, made by Asahi Optical Company of Tokyo, have a CCD detector with an objective lens at its distal end. By comparison with rigid rectoscopes and sigmoidoscopes, however, flexible scopes are costly, fragile and difficult to clean.
It is an object of some aspects of the present invention to provide an improved endoscope, and particularly an improved rectoscope.
It is an object of some aspects of the present invention to provide a video rectoscope that gives improved visibility of anatomical features within the rectum.
It is another object of some aspects of the present invention to provide a rectoscope that is easy and convenient for medical personnel to use.
It is a further object of some aspects of the present invention to provide a rectoscope including an easily-replaceable disposable portion, thus minimizing or eliminating the need for disinfection and sterilization between uses.
It is yet another object of some aspects of the present invention to provide methods and apparatus that facilitate insertion of an endoscope, particularly a rectoscope or sigmoidoscope, into a body cavity.
It is still another object of some aspects of the present invention to provide an improved steering mechanism for an endoscope.
In preferred embodiments of the present invention, a rectoscope comprises an elongate, generally rigid insertion member having a video camera head at its distal end. The insertion member and camera head are covered by a disposable sheath, which includes a transparent distal portion, preferably including an optical window, covering the camera head. The camera head includes an image detector array, preferably a CCD array, as is known in the art, along with a light source for illuminating an area of the intestine viewed by the camera head and an objective lens, which focuses an image of the area onto the array. The sheath, which is preferably made of a biocompatible plastic material, is removed and discarded after use. The rectoscope is used to examine and treat areas of the colon of a patient, specifically the rectal and sigmoid portions of the colon.
By comparison with rigid rectoscopes and sigmoidoscopes known in the art, the present invention can provide substantially improved image quality, because the video camera head is placed at the distal end of the rectoscope, near the area under view. The distal positioning of the camera head enables the present rectoscope to achieve both higher magnification and a wider field of view than video rectoscopes and sigmoidoscopes known in the art, in which the camera head views the intestine through a telescope from the proximal end of the scope.
In preferred embodiments of the present invention, the sheath comprises a narrowed, generally bluntly pointed tip, to ease insertion of the rectoscope through the anus. The narrowed tip thus performs the function of the obturator used in insertion of rectoscopes and sigmoidoscopes known in the art. Elimination of the obturator relieves a physician using the rectoscope of unpleasant odors and possible exposure to infection that are commonly associated with removal of the obturator.
In some preferred embodiments of the present invention, the optical axis of the camera head is angled relative to the longitudinal axis of the insertion member, and the distal end of the sheath is likewise angled, thus defining the narrowed tip. Preferably, the sheath has a bulbous protrusion at the tip, which further eases insertion of the rectoscope through the anus.
In one such preferred embodiment, a mirror is fixed to the bulbous protrusion, which is shaped so that the mirror is positioned within the field of view of the camera head and is oriented obliquely relative to the optical axis thereof An image of the inner wall of the rectum or sigmoid is reflected from the mirror and captured by the camera head. The mirror thus enables the physician to see an image from an alternative view angle, which may be useful particularly in observing and controlling the movement of tools that the physician inserts into the rectum using the rectoscope, as described below.
In other preferred embodiments of the present invention, the narrowed tip of the sheath is formed by a plurality of leaves, formed of a resilient material, which butt together tightly in a closed configuration to cover the transparent portion of the sheath and the camera head. During insertion through the anus, the closed leaves protect the transparent portion from fouling by fecal matter, lubricants or other substances. After the rectoscope has been inserted, the leaves are drawn apart, preferably by pulling the sheath back proximally, so as to expose the transparent portion of the sheath and allow the camera head to receive images of the area of the intestine under view.
In some preferred embodiments of the present invention, the sheath includes one or more worldling channels, which may be used for suction, irrigation, insulation, passage of surgical tools or other functions known in the art. The rectoscope includes a handle, to which the sheath is attached, preferably by a quick connect/disconnect fitting. Preferably, the handle includes user controls for regulating such functions as suction, irrigation and insufflation through the working channels. Further preferably, one or more of the working channels include a one-way valve, to prevent back-flow of fluid (gas or liquid) used in irrigation or insufflation through the channels.
Although rectoscopes in accordance with the present invention are described herein as being generally rigid, in some preferred embodiments the insertion member may include a flexible, resilient longitudinal section. This section allows the rectoscope to bend during insertion into the rectum, to make the insertion easier and less painful for the patient. Such bending is not possible using rigid endoscopes known in the art, and it differs from the bending of flexible endoscopes, which do not have the rigidity to maintain a particular shape and require complex steering mechanisms to control their angle and direction of bend.
In one such preferred embodiment, the rectoscope sheath comprises one or more flexible, longitudinally-disposed inflatable bladders, preferably at least two such bladders disposed radially within the sheath on different sides of the flexible section of the insertion member. Preferably, the bladders are placed on opposing sides of the sheath. The bladders are connected by respective valves to a suitable pressure source. When the pressure in one of the bladders is increased, the bladder lengthens, whereas when the pressure is decreased, the bladder tends to shorten. Thus, the bend angle of the sheath and of the insertion member therein is controlled by varying the pressure in the one or more bladders.
In another preferred embodiment of the present invention, a generally rigid rectal insert having a curved channel therethrough is inserted into the rectum, up to the sigmoid flexure. The insert is turned within the rectum so that the exit from the channel at the sigmoid flexure opens into the intestine in a direction generally along the axis of the sigmoid. The rectoscope including the flexible section, as described hereinabove, is then inserted through the channel and is forced by the rigidity of the insert to bend toward the sigmoid axis. The combination of the insert and rectoscope, in accordance with this preferred embodiment, thus allows endoscopic inspection of a portion of the intestine that can generally be reached only using a more costly flexible endoscope. The rectal insert described herein can also be used in conjunction with flexible endoscopes known in the art, making it easier to pass the endoscope through the sigmoid and reducing pain and the possibility of accidental perforation of the intestine.
Although preferred embodiments are described herein with reference to inspection and treatment of the rectum, and endoscopes in accordance with such preferred embodiments are referred to herein generally as rectoscopes, it will be appreciated that such endoscopes may similarly be adapted and applied to serve as sigmoidoscopes. The principles of the present invention may similarly be applied to produce rigid endoscopes for insertion into other body cavities, such as the throat, the vagina, or any other cavity large enough to receive an endoscope having a video camera head at its distal end, as described herein.
There is therefore provided, in accordance with a preferred embodiment of the present invention, a video endoscope, including:
a generally rigid, elongate insertion member, having distal and proximal ends;
a video camera head fixed at the distal end of the insertion member, and
a sheath, which fits over and covers the insertion member, the sheath having a distal portion covering the video camera head, at least a section of which distal portion is substantially transparent.
Preferably, the camera head includes a detector array and an objective lens, which forms an image on the detector array.
In a preferred embodiment, the camera head is inclined obliquely relative to a longitudinal axis of the insertion member.
Preferably, the camera head includes a light source, most preferably including one or more LEDs.
Preferably, the substantially transparent section of the distal portion of the sheath includes an optical window.
Preferably, the distal portion of the sheath includes a narrowed tip, which facilitates insertion of the endoscope through the anus. Further preferably, the narrowed tip includes a bulbous protrusion.
Alternatively or additionally, the narrowed tip includes two or more leaves, which are closed during insertion through the anus and open apart after insertion to expose the transparent section of the distal portion of the sheath. Preferably, to open the leaves, the sheath is shifted in a proximal direction drawn relative to the insertion member.
Preferably, the sheath contains a worldling channel passing longitudinally therealong. Further preferably, the sheath includes a one-way valve within the worldling channel, for preventing back-flow of fluid therethrough.
Preferably, the endoscope includes a handle, fixed to the proximal end of the insertion member, and the handle includes user controls for controlling the passage of fluid through the working channel.
In a preferred embodiment, at least a longitudinal section of the insertion member is flexible and resilient. Preferably, the sheath includes an inflatable bladder disposed longitudinally within the sheath, such that inflation of the bladder causes its length to increase so that the insertion member bends.
In another preferred embodiment, a mirror is fixed in a position distal to the camera head within a field of view thereof and oriented obliquely relative to an optical axis of the camera head, so that the camera head captures an image reflected from the mirror. Preferably, the image reflected from the mirror includes an area of a physiological structure in which a surgical procedure is to be performed using the endoscope.
There is further provided, in accordance with a preferred embodiment of the present invention, a steering mechanism for an elongate medical probe, including at least one controllably inflatable element fixed to the probe, such that a longitudinal dimension of the element changes responsive to inflation thereof thereby causing the probe to bend.
Preferably, the at least one inflatable element includes two elements disposed radially on different sides of the probe, so as to bend the probe in different, respective directions. Further preferably, the two elements include first and second elements on opposing sides of the probe, such that the first element is inflated and the second element is deflated so as to bend the probe toward the side on which the second element is fixed.
Preferably, the at least one inflatable element includes an expandable wall section on an outer surface thereof, which expands and contracts responsive to changes in the inflation of the element.
Preferably, the mechanism includes a pressure source which is controllably applied to the inflatable element so as control the bending of the probe.
In a preferred embodiment, the probe includes a generally rigid endoscope, having a flexible section which is bent by the mechanism, wherein the endoscope preferably includes a disposable sheath, which includes the at least one inflatable element.
There is moreover provided, in accordance with a preferred embodiment of the present invention, a generally rigid rectal insert, having a distal end which is inserted into the rectum of a patient, the insert having a curved channel therethrough through which an endoscope is inserted into the sigmoid portion of the colon of a patient.
Preferably, the distal end of the insert is brought into proximity with the patient""s sigmoid flexure, and the channel is curved so as to open laterally out of the distal end into the flexure. Further preferably, the insert is rotatable within the rectum so as to align the opening of the channel at the distal end thereof with the intestine.
There is also provided, in accordance with a preferred embodiment of the present invention, a method of endoscopic inspection, including:
providing an elongate, generally rigid insertion member having a video camera head at a distal end of the member;
fitting a disposable sheath over the member, such that the camera head is covered by a substantially transparent portion of the sheath;
inserting the insertion member, covered by the sheath, into a body cavity of a subject; and
receiving video images within the body cavity from the camera head.
Preferably, fitting the sheath includes fitting a sheath having a narrowed tip, and inserting the member includes first inserting the narrowed tip into the cavity.
In a preferred embodiment, the narrowed tip is opened after insertion to expose the substantially transparent portion of the sheath covering the camera head, wherein opening the narrowed tip preferably includes shifting at least a portion of the sheath in a proximal direction over the insertion member so as to separate two or more leaves that meet to form the narrowed tip.
Preferably, receiving the video images includes illuminating the inside of the body cavity using a light source in the video camera head.
Further preferably, fitting the disposable sheath includes fitting a sheath having at least one working channel passing therethrough. In a preferred embodiment, the body cavity is insufflated by passing a pressurized fluid through the working channel.
In a preferred embodiment, providing the insertion member includes providing a member at least a longitudinal portion of which is flexible and resilient, and inserting the member includes flexing the flexible, resilient portion. Preferably, inserting the member includes inserting an insert into the body cavity having a curved channel therethrough, and passing the member through the channel. Alternatively or additionally, flexing the flexible, resilient portion includes inflating an inflatable bladder disposed within the sheath so that the length of the bladder increases, thereby bending the portion.
Preferably, inserting the insertion member includes inserting the member through the anus of the subject, and receiving the images includes receiving images within the rectum or, alternatively or additionally, receiving images within the sigmoid.
There is further provided, in accordance with a preferred embodiment of the present invention, a method for steering a medical probe, including:
fixing an inflatable element to the probe; and
controllably inflating the element so as to change the length thereof, thus causing the probe to bend.
Preferably, fixing the inflatable element includes fixing a plurality of elements on different sides of the probe, so that each element causes the probe to bend in a different, respective direction.
In a preferred embodiment, the medical probe includes a generally rigid endoscope at least a section of which is flexible, and wherein controllably inflating the element causes the flexible section of the endoscope to bend.
There is additionally provided, in accordance with a preferred embodiment of the present invention, a method for inserting an endoscope into the colon of a patient, including:
providing a generally rigid insert having proximal and distal ends and having a curved channel passing therethrough with a lateral opening at the distal end;
inserting the insert into the patient""s rectum so that the distal end is in proximity to the sigmoid flexure of the colon; and
passing the endoscope through the channel and into the sigmoid colon.
Preferably, the insert is rotated to align the opening at the distal end of the insert with the colon before passing the endoscope therethrough.
Preferably, passing the endoscope includes passing a flexible endoscope through the channel or, alternatively, passing a generally rigid endoscope including a flexible portion through the channel, such that the flexible portion is bent by the curve of the channel.
The present invention will be more fully understood from the following detailed description of the preferred embodiments thereof, taken together with the drawings in which: