WO2007110620A1

WO2007110620A1 - Endoscope with a plurality of image capturing means

Info

Publication number: WO2007110620A1
Application number: PCT/GB2007/001083
Authority: WO
Inventors: Tarek Abdelhakim Salem
Original assignee: Tarek Abdelhakim Salem
Priority date: 2006-03-24
Filing date: 2007-03-26
Publication date: 2007-10-04
Also published as: GB0605931D0

Abstract

An endoscope comprising a shaft and a plurality of image capturing means, wherein at least two image capturing means are displaced longitudinally relative to each other along the length of the shaft. The invention also relates to methods for the detection and correction of looping of an endoscope.

Description

ENDOSCOPE WITH A PLURALITY OF IMAGE CAPTURING MEANS

Field of the invention

The present invention relates to an endoscope, more specifically to an endoscope that includes more than one image capturing means . The invention also relates to methods for the detection and correction of looping of an endoscope

Background to the invention Endoscopy involves the visual inspection of a body cavity using an endoscope. Endoscopes conventionally comprise a shaft through which light bundles and other contents are tightly packed inside a water proof layer. The light bundles permit light to be transmitted from the proximal end of the endoscope to the distal end of the endoscope in order to illuminate the area to be visualised. An image capture means such as a charge coupled device camera is normally provided at the distal end of the endoscope which transmits images down through the shaft to the proximal end of the endoscope where the image is resolved on a monitor for the user to see. Charge coupled devices are small enough to fit in the tip of an endoscope but large enough to provide sufficient pixels to enable high quality digital images .

Endoscopy is becoming an increasingly important clinical technique. For example, colonoscopy (a central diagnostic and therapeutic technique for patients with colorectal diseases) is expected to increase in frequency of use in the UK after the introduction of a national colorectal screening programme. New techniques are being developed in this field such as NOTES (Natural Orifice Transluminal Endoscopic Surgery) . Thus, it is important that the technique should be safe, reasonably quick, acceptable to patients, and carries minimal risk (risks associated with such procedures are perforation and Haemorrhage) .

The main problem with endoscopic techniques such as colonoscopy is that they are "push" techniques which inevitably result in "looping" of the shaft within the body cavity or passage. A variety of shaped loops may form, e.g. N-loops or α-loops. Looping prevents the progression of the distal end of the endoscope through the body passage and increases the stress on the body passage in the region of the loop. Looping therefore halts the progress of the procedure and can cause variable degrees of patient discomfort and possible complications. The endoscopist has no means of seeing what is happening to the shaft of the endoscope during the procedure and so can be unaware that looping is occurring. It is important to detect looping as early as possible during an endoscopic procedure in order to prevent excess stress on the body passage, which can be rectified by partially withdrawing and then straightening the endoscope.

Various techniques have been tried to identify and correct looping of the endoscope shaft in order to provide a procedure that is smooth, quick and has no or minimal patient discomfort. Magnetic Endoscope Imaging (MEI) is one of those techniques. However, MEI is costly, needs relatively large amounts of space for bulky equipment and conducting coils to be arranged around the shaft and along its length. There is no means of visualising the colonic lumen with MEI. In addition, it cannot be used for patients with pacemakers or implanted defibrillators.

Variable stiffness scopes have also been used to prevent looping but with variable results.

Accordingly, it is an object of the present invention to provide an endoscope that enables the user to detect looping more easily and quickly than conventional endoscopes, without the aforementioned problems associated with known techniques for detecting looping, and so provide a faster and safer method of detecting^' and correcting looping in an endoscopic procedure. The present invention also provides educational aspects for endoscopy trainees . Summary of the invention

According to one aspect of the present invention, there is provided an endoscope comprising a shaft and a plurality of image capturing means, wherein at least two image capturing means are displaced longitudinally relative to each other along the length of the shaft.

The advantage of providing at least two image capturing means arranged in this way is that one image capturing means may be employed for making the_. visual inspection of the passageway into which it is inserted, whilst the other image capturing means may visualise a portion of the shaft of the endoscope in the direction in which the image capturing means is pointed and so is able to capture images of a loop forming. Thus, by viewing the resolved images transmitted from both image capturing means, the user is able to monitor the progression of the endoscope through the passageway and easily identify the early stage of loop formation. Lesions in the body passage not detected by the distal tip image capturing means may also be recognised by more proximal image capturing means attached to the shaft of the endoscope.

The endoscope is not a capsule endoscope. Preferably, one of the at least two image capturing means is provide at or near the distal end of the shaft. It is the image capturing means provided at the distal end of the shaft that is the image capturing means that is used to visualise the passageway in front of the advancing endoscope. Whilst it is preferred that image capturing means at the distal end of the shaft is provided at the tip of the shaft, it must be realised that providing the image capturing means at any position near the tip such that it is still able to visualise the passageway in front of the advancing endoscope is also contemplated. This image capturing means may be a conventional image capturing means provided at the distal end of a shaft, for example, it may not be capable of movement and relies on the four-way directional movement of the distal end of the shaft to change the viewing position and may have a 140° field of view. Alternatively, the image capturing means may be those described below and so capable of independent movement from the shaft.

For the avoidance of doubt, the distal end of the shaft is the end that is furthest from the user of the endoscope and is the first portion of the shaft that .is inserted into the passageway to be investigated. The opposite end of the shaft is termed the proximal end. It has been found that most loops form in the first metre of the shaft of colonoscopes, as they pass through the sigmoid colon (about 80% of all colonoscopies) , and through the deep transverse colon (about one third of all colonoscopies) .

Thus, in a preferred embodiment of the present invention the at least two image capturing means are provided along the first metre of the shaft from the distal end. As most looping tends to occur in this first metre, the applicant has found that image capturing means provided in this portion of the length of the shaft are able to visualise most looping. All image capturing means may be provided in this portion of the length of the shaft.

The at least two image capturing means can be displaced, relative to each other along the length of the shaft, by any distance that permits the more proximally positioned image capturing means to view a portion of the shaft between the more proximally positioned image capturing means and the more distally positioned camera. Therefore, the at least two image capturing means are not be placed side-by-side at the distal tip of the shaft (e.g. they are not placed in the manner of image capturing means in a stereoscopic endoscope) . Preferably, the at least two image capturing means are displaced by more than 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8 metres relative to each other along the length of the shaft. Preferably, the at least two image capturing means are displaced by less than 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6 or 0.5 metres relative to each other along the length of the shaft. The at least two image capturing means may be displaced by a distance that is encompassed by a range from any of more than 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8 to any of less than 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6 or 0.5 metres relative to each other along the length of the shaft, most preferably from 0.3 to 0.6 metres . In order to visualise looping or multiple looping at different portions along the length of the shaft the endoscope may include 2, 3, 4, 5, 6, 7, 8, 9, or more image capturing means proved along the length of the shaft, preferably at regular intervals . The regular intervals may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8 metres, most preferably from 0.3 to 0.6 metres. The endoscope may also comprise two or more image capturing means provided at the same length along the shaft of the endoscope. In this way two or more image capturing means may be able to visualise the same length of the endoscope and surrounding wall of the body passage but from a different side of the endoscope, thereby permitting the user to more easily determine in which direction the shaft is looping. One or more of the image capturing means may be fixed in position on the shaft, facing towards the proximal end of the shaft or towards the distal end of the shaft. However, for the more proximalIy positioned image capturing means to visualise along the shaft of the endoscope they must capable of protruding out from the profile of the shaft. Such a protrusion can cause damage to the soft tissue of the body passageways and so is not desirable.

Accordingly, in a preferred embodiment of the present invention the endoscope is configured such that at least one of the image capturing means can switch from a stowed position, wherein the image capturing means is retained within the shaft of the endoscope, and a viewing position, wherein the image capturing means extends away from the shaft of the endoscope.

Preferably, when the image capturing means is in the stowed position the image capturing means is substantially entirely retained within the shaft of the endoscope. Thus, when the image capturing means is in the stowed position its external profile is substantially flush with the external profile of the shaft of the endoscope. For example, the endoscope may further comprise a housing within the shaft in which the image capturing means may be stowed. The housing is preferably shaped to house the image capturing means . In the aforementioned configurations the image capturing means can be withdrawn into the housing within the shaft of the endoscope so that there can be no harmful protrusions from the shaft, and is only required to extend when a view along the shaft is required.

The endodoscope may further comprise a water tight skin that covers that outer surface of the shaft extends over the surface of the housing in which the image capturing means rests when in the stowed position. Thus, creating a,. barrier between the lumen of the body passage and the contents of the shaft. The point of attachment of the image capturing means to the shaft may be at the skin of the shaft or may pass through the skin of the shaft into the lumen of the shaft (in such an embodiment a seal, such as a washer, should be provided at the break in the skin through which the attachment of the image capturing means to shaft passes to prevent contaminants from the body passage leaking into the contents of the endoscope) .

Preferably, when the image capturing means is in the viewing position the image capturing means can view along the external surface of the endoscope towards the distal end of the endoscope. It is also preferred that the image capturing means is not fixed in a single viewing position. Thus, when the image capturing means is in the viewing position the image capturing means may be configured so as to enable multi-directional viewing. This may enable viewing of areas normally not seen easily with conventional endoscopes, such as Ampula of Vater during Endoscopic Retrograde Cholangio-Pancreatography (ERCP) .

The image capturing means provided for viewing along the shaft is preferably more proximally positioned relative to the image capturing means provided at the distal end of the endoscope.

The ability for the image capturing means to extend from a housed position within the shaft to an extended position out of the shaft, and to rotate for mulit-directional viewing when in the viewing position, can be engineered in a number of ways. However, by way of example, the image capturing means may be pivotalIy retained within or to the shaft of the endoscope, thereby permitting the image capturing means to pivot from the stowed position to the viewing position. A pivotal arrangement may also permit the image capturing means to rotate around the pivot point when in the viewing position and so permit multi- ^ ^

directional viewing. The image capturing means may be pivoted around a ball and socket joint. In order that the image capturing means may get an optimum view along the shaft, the image capturing means can pivot so as to be at substantially at 90², or more, to the external surface of the body of the endoscope.

The endoscope may further comprise actuation means which are transmitted through the shaft of the endoscope and connect the image capturing means to control means provided at the proximal end of the endoscope, wherein said actuation means are configured to urge the image capturing means from the stowed position to the viewing position. Second actuation means may also be provided which are transmitted through the shaft of the endoscope and connect the image capturing means to the control means provided at the proximal end of the endoscope, wherein the said second actuation means are configured to rotate the image capturing means so as to allow multi-directional viewing when in the viewing position. The first and/or second actuation means are preferably tension cables or springs, or a mixture thereof. For example, the image capturing means may be spring biased towards rest when housed within the shaft. The image capturing means may, however, be drawn from the housing by increasing the tension of a tension cable attached to the side of the camera means that opposes the housing. In such embodiments the actuation means act essentially like tendons in an arm that are able to flex and straighten a finger.

In a further preferred embodiment of the present invention, the endoscope may be configured such that at least one of the image capturing means can move along at least a portion of the length of the shaft. This movement may be achieved in any manner of ways, for example, a track may be provided along at least a portion of the length of the shaft on which the image capturing means may travel . In order to permit the image capturing means to move along the shaft without injuring any soft tissue of the passage within which the endoscope is inserted, the image capturing means preferably has an aerodynamic profile (i.e. a tapering to flat anterior and posterior edge) . Alternatively, or in addition the shaft may include a channel that runs along a portion of the length of shaft in which the image capturing means may travel . A portion of the length of shaft may be the whole length of the shaft or less than 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1., 1.2 metres from the distal end of the shaft. This preferred embodiment of the present invention may include any of the features of the earlier described embodiments of the present invention. For example, the image capturing means that can move along at least a portion of the length of the shaft may be configured such that it may also switch from a stowed position to a viewing position in the same manner as described above for the earlier described embodiments . This may be achieved by providing the image capturing means with an axle, around which the image capturing means can pivot from the stowed to the viewing position, and which can be connected to one or more wheels on which the image capturing means run (preferably, at least two wheels, one wheel provided at each end of the axle) .

Any form of image capturing means that provides sufficient clarity and is small enough to be. provided in the shaft may be used. Preferably the image capturing means is a camera, more preferably a charge coupled device chip or a light emitting diode (fibre optics may not be required when using a light emitting diode camera) .

The shaft of the endoscope may include markings on the outer surface that provide an indication of the depth of insertion of the endoscope. These marking may assist in understanding the orientation of the image capturing means that visualise the markings. For example, if the image capturing means -which are preferably inserted close to a numbered marking on the endoscope- visualises an inverted number like inverted numbered marking at 0.3 meter distance from the tip, this would indicate to the user that the ^

image capturing means is either facing away from^' the distal end of the shaft or that the shaft itself is rotated or torqued clockwise/anticlockwise. .

In order to display the images in the clearest manner the endoscope may further comprise a split screen monitor, wherein an image captured in each of the image capturing means is displayed on a separate portion of the split screen monitor.

The endoscope is preferably a colonoscope.

In a further aspect of the present invention, there is provided a method of detection and correction of looping of an endoscope comprising the steps of:

(a) inserting the endoscope recited in any of the preceding claims in through an orifice and along a passageway whilst monitoring the image provided by the at least two image capturing means; (b) withdrawing and straightening the shaft of the endoscope when the image transmitted from the proximally disposed image capturing means shows looping;

(c) returning to the step of urging the endoscope through the passageway. When viewing the loop it may be possible to understand which direction the loop is formed in and so provide the user with an indication of the direction to straighten the shaft of the endoscope. Thus, the method may include the step of straightening the shaft of the endoscope by twisting in a direction that is opposed to the direction of the loop, as visualised by the image capturing means.

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: -

Figure 1 shows a side view of the distal end of an endoscope according to the present invention that includes two cameras .

Figure 2 shows a side view of the distal end of an endoscope according to the present invention that includes 5 cameras .

Figure 3 shows a side view of the distal end of an endoscope according to the present invention that includes a longitudinally moveable camera.

Figure 4 shows a sectional view along lines X-X of the endoscope of Figure 3. Figure 5 shows a sectional view of the ball and socket joint of an endoscope according to the present invention.

Figure 6 shows the first actuating means according to the present invention.

Figure 7 shows the second actuating means according to the present invention.

The proximal tip of the endoscope of the present invention, as illustrated in figure 1, comprises a shaft (1) with a distal camera (2) , provided at the distal end of the shaft, and a proximal camera (3), provided proximally along the shaft relative to the distal camera. The proximal camera

(3) is shown in the viewing position, from where it can visualise the shaft as it extends towards the distal camera. The camera is able to extend out from the housing

(4) within the shaft by pivoting around the pivot point (5) . The shaft (1) and housing (4) are covered by a flexible skin that prevents any contamination entering the lumen of the endoscope. The cameras are CCD chip cameras. A light bundle (not shown) for light transmission is transmitted through the shaft and exits the shaft along with the cameras so as to illuminate the area in front of ^

each camera. The cameras are displaced longitudinally along the shaft by 0.45 metres relative to each other.

The distal tip of the endoscope of the present invention, as illustrated in figure 2, is substantially similar to that of figure 1, except it includes five cameras; one distal camera (2) and four more proximally positioned cameras (3) . The middle proximal camera (3) provided on the left hand side of the shaft (1) is shown in the stowed position where it is embedded into the substance of the colonoscope within a housing (4) , which is specifically designed to host the camera so that it's outward face is in line with the contours of the circumference of the colonoscope. A further proximal camera (3) is provided at the same distance from the distal end of the shaft (1) as the aforementioned stowed camera (3), but on the opposite side of the shaft. When both these cameras are in the viewing position it enables them to look down the same length of the shaft (1) but from different sides, thereby giving the user more information relating to the orientation of any looping that may be visualised. The most proximally positioned camera (3) is pivoted out into the viewing position and pivoted around so as to view along the shaft in the opposite direction from the distal tip of the shaft (1) . The most distally positioned proximal camera (3) is configured so as to be stowed and opens into a viewing position in which the camera faces towards the proximal end of the shaft (1) . Each of the proximal cameras (3) on the left hand side of the shaft (1) are separated by a distance of 0.45 metres.

The endoscope of the present invention, as illustrated in Figure 3, differs from the endoscope provided in the earlier figures by the fact that the more proximally positioned camera (3) is not fixed in one position but is able to move longitudinally up and down the shaft (1) . The shaft (1) includes a channel (6) that runs along the length of the shaft and into which the proximal camera (3) is able to run. The proximal camera runs on tracks (not shown) provided at the base of the channels. Tension cable (7) is attached to the proximal camera (3) and runs the length of the shaft (1) to control knobs, which can be used by the user to change the longitudinal positioning of the proximal camera (3) . The more proximally positioned camera is spring biased so as to return to the distal end of the shaft once tension on the cable (7) is removed.

Figure 4 shows a cross sectional view, across line X-X, of the shaft (1) illustrated in Figure 3. It can be seen that when the camera is embedded within the channel (6) it is substantially flush with the outer surface of the shaft (D • A ball and socket joint (8) of the pivot point (5) is illustrated in Figure 5. Part of the ball and socket joint (8) is fixedly received within the shaft (1) with the other part extending through the skin of the shaft (1) where it joins the proximal camera (3) . In order to prevent any contaminants leaking into the lumen of the shaft (1) an o- ring washer (9) is provided at the portion of the ball and socket joint (8) that crosses the skin. The arrows indicate the various movements that the proximal camera (3) make by virtue of the attachment to the shaft (1) via the ball and socket joint (8) . Thus the camera is able to move from the stowed to viewing position and able to look forward or backward along the shaft (1) .

Figure 6 illustrates the first actuating means that enable the proximal camera (3) to pivot around the ball and socket joint (8) so as to move from the stowed position to the viewing position. A first tension cable (10) is attached to the side of the camera that is opposed to the housing (4) and is transmitted through the lumen of the shaft (1) to a control knob (12) . When the control knob (12) is turned anti-clockwise the fist tension cable tightens and the camera is urged into the viewing position. A second tension cable (11) is attached to the side of the camera that is closest to the housing (4) and is transmitted through the lumen of the shaft (1) to a control knob (12) . When the control knob (12) is turned clockwise the first tension cable tightens and the camera is urged into the stowed position. Alternatively, but not shown, the second tension cable (11) may be omitted and replaced with a spring that biases the camera into the stowed position.

The knob is a wheel knob and is provided below the usual control buttons used in a colonoscope i.e. within a short distance below the air button/water button and within reach of the colonoscopist's hand.

Figure 7 illustrates the second actuating means that enable the proximal camera (3) to pivot around the ball and socket joint (8), when in the viewing position, so as to enable multi-directional viewing. A third tension cable (13) is fixed to the proximal camera (3) after it wraps around the base of the proximal camera (3) in a clockwise direction. The remainder of the third tension cable (13) is transmitted through the lumen of the shaft (1) to a control knob (12) . When the control knob (12) is turned clockwise the third tension cable tightens and the camera is urged to rotate in an anti-clockwise direction. A fourth tension cable (14) fixed to the proximal camera (3) after it wraps around the base of he. proximal camera (3) in an anticlockwise direction. The remainder of the fourth tension cable (14) is transmitted through the lumen of the shaft (1) to a control knob (12) . When the control knob (12) is turned anti-clockwise the fourth tension cable tightens and the camera is urged to rotate in a clockwise direction.

The present invention has been described above purely by way of example. It should be understood that modifications in detail may be made within the scope of the invention.

Claims

1) An endoscope comprising a shaft and a plurality of image capturing means, wherein at least two image capturing means are displaced longitudinally relative to each other along the length of the shaft.

2) An endoscope as claimed in claim 1, wherein one of the at least two image capturing means is provided at or near the distal end of the shaft.

3) An endoscope as claimed in any of the preceding claims, wherein the at least two image capturing means are provided along the first metre of the shaft from the distal end.

4) An endoscope as claimed in any of the preceding claims, wherein the at least two image capturing means are displaced by more than 0.3 metres relative to each other along the length of the shaft.

5) An endoscope as claimed in any of the preceding claims, wherein the at least two image capturing means are displaced by less than 1 metre relative to each other along the length of the shaft.

6) An endoscope as claimed in any of the preceding claims, wherein the endoscope- is configured such that at least one of the image capturing means can switch from a stowed position, wherein the image capturing means is retained within the shaft of the endoscope, and a viewing position, wherein the image capturing means extends away from the shaft of the endoscope. 7) An endoscope as claimed in claim 6, wherein when the image capturing means is in the stowed position the image capturing means is substantially entirely retained within the shaft of the endoscope. 8) An endoscope as claimed in claim 6 or claim 7, wherein when the image capturing means is in the stowed position its external profile is substantially flush with the external profile of the shaft of the endoscope. 9) An endoscope as claimed in any of claim 6 to 8, further comprising a pocket within the shaft of the endoscope that is shaped to house the image capturing means . 10) An endoscope as claimed in any of claims 6 to 9, wherein when the image capturing means is in the viewing position the image capturing means can view along the external surface of the endoscope towards the distal end of the endoscope. 11) An endoscope as claimed in any of claims 6 to 10, wherein when the image capturing means is in the viewing position the image capturing means is configured so as to enable multi-directional viewing. 12) An endoscope as claimed in any of claims 6 to 11, wherein the image capturing means recited in claim 6 is more proximally positioned relative to the image capturing means provided at the distal end of the endoscope. 13) An endoscope as claimed in any of claims 6 to 12, wherein the image capturing means is pivotally retained at the shaft of the endoscope, thereby permitting the image capturing means to pivot from the stowed position to the viewing position.

14) An endoscope as claimed in any of claims 6 to 13, wherein the image capturing means is pivotally retained at the shaft of the endoscope, thereby permitting the endoscope to rotate around the pivot point when in the viewing position and so permit multi-directional viewing.

15) An endoscope as claimed in claims 13 or 14, wherein the image capturing means is pivoted around a ball .and socket joint.

16) An endoscope as claimed in any of claims 6-15, wherein the image capturing means can pivot so as to be at substantially at 90^s to the external surface of the body of the endoscope.

17) An endoscope as claimed in any of claims 6 to 16, further comprising actuation means which are transmitted through the shaft of the endoscope and connect the image capturing means to control means provided at the proximal end of the endoscope, wherein said actuation means is configured to urge the image capturing means from the stowed position to the viewing position.

18) An endoscope as claimed in claim 17, further comprising a second actuation means which are transmitted through the shaft of the endoscope and connect the image capturing means to the control means provided at the proximal end of the endoscope, wherein said actuation means is configured to rotate the image capturing means so as to allow multi-directional viewing when in the viewing position. 19) An endoscope as claimed in any of claims 17 and 18, wherein the first and/or second actuation means are tension cables .

20) An endoscope as claimed in any of claims 1 to 19, wherein the endoscope is configured such that at least one of the image capturing means can move along at least a portion of the length of the shaft.

21) An endoscope as claimed in claim 20, further comprising a track provided along at least a portion of the length of the shaft and on which the image capturing means may travel .

22) An endoscope as claimed in claim 20 or claim 21, further comprising a channel provided in the shaft that that runs along at least a portion of the length of the shaft and in which the image capturing means may travel.

23) An endoscope as claimed in any of the preceding claims, wherein the image capturing means is a camera.

24) An endoscope as claimed in claim 23, wherein the camera is a charge coupled device chip.

25) An endoscope as claimed in any of the preceding claims, further comprising a split screen monitor provided towards the proximal end of the endoscope, wherein an image captured in each of the image capturing means is displayed on a separate portion of the split screen monitor.

26) An endoscope as claimed in claim 25, wherein the endoscope is a colonoscope.

27) A method of detection and correction of looping of an endoscope comprising the steps of:

(a) inserting the endoscope recited in any of the preceding claims in through an orifice and along a passageway whilst monitoring the image provided by the at least two image capturing means;

(b) withdrawing and straightening the shaft of the endoscope when the image transmitted from the proximally disposed image capturing means shows looping; (c) returning to the step of urging the endoscope through the passageway.

28) An endoscope substantially as hereinbefore described with reference to and as shown in Figures 1 to 7. 29) A method substantially as hereinbefore described with reference to and as shown in Figures 1 to 7.