Field of Invention;
The present invention relates to diagnostic and operative continuous flow irrigation endoscopes to be used in surgeries such as hysteroscopy, arthroscopy and urology. More specifically the present invention basically relates to minimizing the size of the endoscope and the present invention relates to endoscopes which have a round cross section or an oval like cross section. The said present invention is especially useful in context with the small size endoscopes.
Background of the Invention:
The basic purpose of the present application is to minimize the size of a continuous flow irrigation endoscope. A small size endoscope causes less tissue trauma and less pain to the patient in comparison to a larger size endoscope. The term 'endoscope size' relates to the outer diameter of the endoscope and not to the long length of the endoscope. In the conventional prior art endoscopes reducing the size of the endoscope generally reduces the surgical efficiency of the endoscope. The present application relates to reducing the size of the endoscope without reducing the surgical efficiency of the endoscope.
The endoscope size can be reduced by reducing the cross sectional size of the components of the endoscope such as the fluid flow channels, the telescope and/or the instrument, however the same is undesirable because:
• Reducing the size of the telescope impairs the image quality by limiting the number and/or size of the fiber optic bundles.
• Reducing the size of the outflow fluid channel makes it difficult to evacuate air bubbles such as those produced during bipolar or monopolar surgery. Such bubbles can cause cardiac air embolism and they also obstruct endoscopic vision.
• Reducing the size of the inflow fluid channel makes it difficult to instill fluid into the tissue cavity thereby making it difficult to achieve a desired cavity pressure and thereby a desired mechanical distension of the tissue cavity.
• Any reduction in the size of the endoscopic instrument could reduce the surgical efficiency and also increase the surgical time.
The present application relates to minimizing the size of a continuous flow irrigation endoscope without reducing the size of the fluid flow channels, the telescope and/or the instrument. Alternatively stating the present application allows to maximize the cross
sectional size of the component/s of a continuous flow irrigation endoscope without increasing the size of the endoscope. The said endoscope has a 'proximal' end which is always located towards and near the surgeon and a 'distal' end which enters into a body tissue cavity.
In context with the present application the term 'continuous flow irrigation' means that fluid simultaneously enters into and escapes out of a body tissue cavity through separate independent entry and exit points, as a result of which a positive pressure is created inside the body tissue cavity which distends the tissue cavity. A 'continuous flow irrigation endoscope' at least requires an inflow fluid channel and an outflow fluid channel in order to function. The telescope, if at all, could be introduced separately such as via a separate 'incision or stab wound' made over the wound cavity as frequently practiced in arthroscopy, or alternatively the telescope is placed inside the lumen of the endoscope as practiced in hysteroscopy and urology. Similarly, the endoscopic instrument/s, if at all, could be passed through a separate stab would as frequently practiced in arthroscopy or alternatively the endoscopic instrument is placed inside the lumen of the endoscope as practiced in hysteroscopy and urology. In this entire manuscript the items such as the inflow fluid channel, the outflow fluid channel, a telescope and or instrument/s shall be referred to as 'components of the endoscope'. Also in this manuscript the total cross sectional area of the endoscope which is available for being occupied by the said 'components of the endoscope' shall be referred to as the 'effective cross sectional area' of the endoscope.
The inflow channel is a fluid transporting channel located inside the endoscope and is utilized to instill irrigation fluid inside a tissue cavity. The proximal end of the inflow channel ends in an adaptor known as the inflow port while the distal end of the inflow channel opens near the tip of the endoscope. The inflow port is connectable to an inflow tube which carries sterile irrigation fluid from a fluid source reservoir to the body tissue cavity. The out flow channel is a fluid transporting channel located inside the endoscope and is utilized to remove the dirty waste fluid from the tissue cavity. The proximal end of the outflow channel ends in an adaptor known as the outflow port while the distal end of this outflow channel opens near the tip of the endoscope. The outflow port is connectable to an outflow tube which transports the waste fluid from the cavity to a waste fluid collecting container.
The conventional continuous flow irrigation endoscope comprises of an inner tube placed inside the lumen of an outer tube. The inner tube functions as a first fluid flow channel, while the potential space between the outer and the inner tube functions as the second fluid flow channel. In such arrangement the effective cross sectional area of the endoscope is undesirably reduced because the inner tube occupies a part of the luminal cross section of the endoscope. Accordingly and logically, if the inner tube is some how discarded then the area occupied by the same can be beneficially allocated to any or all of the components of the endoscope. Thereby implying that if the inner sheath is discarded then the outer diameter of the shaft of the endoscope can be beneficially reduced without reducing the size of any or all of the 'components of the endoscope', and vice versa, and in the present application the same is achieved by utilizing a rigid planar sheet for the purpose of creating the inflow and the outflow fluid flow channels.
Also in the said conventional continuous flow irrigation endoscope comprising of an inner tube placed inside the lumen of an outer tube, the distal most end of the outer sheath converges in a tapering manner over the distal most end of the inner sheath and in this manner a closed cavity of a fluid channel is formed between the two tubes, and that the fluid enters into this 'closed cavity' through multiple small holes provided over a distal small length of the outer sheath. Referring to the described tapering arrangement reduces the distal most end of the endoscope has a relatively smaller diameter the rest of the entire proximal length of the endoscope length undesirably maintains a relatively greater outer diameter. Again referring to the described tapering arrangement of the conventional continuous flow irrigation endoscope the endoscope shaft does not maintain a same uniform diameter and cross sectional shape. In the system of the present application the entire shaft of the endoscope retains a same uniform diameter and cross sectional shape.
A small size endoscope causes less tissue trauma and less pain to the patient in comparison to a larger sized endoscope. Hence many companies have started to market the same, for example Karl Storz-Endoscope (Tuttlingen) is marketing the new generation of Bettocchi Hysteroscopes (catalogue number 26152 B1/BO) to be used in office hysteroscopy. The Bettocchi micro Hysteroscope has an oval like cross section with a maximum outer dimension/size of 4.2 mm and the two fluid channels are created by placing an inner sheath inside an outer sheath. The inner sheath functions as the inflow fluid channel and an endoscopic instrument is also passed through this channel. As already described in context
with a conventional prior art continuous flow irrigation endoscope, the potential space between the outer and the inner sheath functions as the out flow fluid channel. In the described Bettocchi micro Hysteroscope both the fluid flow channels have a relatively small area of cross section and hence a relatively higher resistance to fluid flow, which also do not allow the physician to use the conventional methods to distend the uterine cavity such as compressive cuff or gravity. The telescope is supported inside a cylinder like channel which we shall arbitrarily refer to as an 'optic sleeve' in this entire manuscript for the sake of an easy reference. The said 'optic sleeve' in placed inside the potential space between the inner and the outer sheath. The inner sheath and the optic sleeve undesirably occupy a substantial part of the cross sectional area related to the lumen of the Bettocchi endoscope. In the present application an additional optic sleeve is not utilized for supporting the telescope because the 'optic sleeve' tends to reduce the available effective cross sectional. A major disadvantage Bettocchi endoscope is its relative in efficiency to evacuate air bubbles produced during electrosurgical procedure specially bipolar surgery. Besides obstructing hysteroscopic vision the air bubbles can also cause a fatal pulmonary embolism. Based on the principals of fluid mechanics, the reasons related to a difficult evacuation of the air bubbles in the Bettocchi endoscope, as follows:
(1) High fluid resistance: A relatively small cross section of the outflow fluid channel increases the outflow resistance to fluid flow thereby retarding the evacuation of air bubbles.
(2) Reduced effective outflow rate: The waste fluid enters into the outflow channel usually via a total of ten holes, that is a set of five holes each placed on each side of the outer sheath near its distal end. Let the outflow rate be hypothetically assumed to be 100 ml/min, wherein the term 'outflow rate' is the rate at which the waste bloody fluid escapes out of the outflow port. In such described hypothetical arrangement the waste fluid actually enters into each of the any ten holes at 10 ml/min thereby aggregating to a total of 100 ml/mil which cumulatively escapes out of the outflow port. Thus from a fluid mechanics point of view the effective flow rate which is available for evacuating an air bubble through any one of the ten holes is mere 10 ml/min and not 100 ml/min. The efficiency with which an air bubble is sucked into an outflow hole is a function of the effective outflow rate per hole such that the said 'efficiency' increases as the said 'flow rate' per hole increases. Hence the air bubbles are evacuated with the greatest efficiency if the ten holes are substituted with a single hole having an effective outflow rate of 100 ml/min instead of 10 ml/min, and the same is achieved in the system of the present application. (3) Circumferentially located outflow holes: Fluid enters into each of the ten outflow holes at 90 degrees to the endoscope shaft and
thereafter the outflow fluid flow vector immediately bends by 90 degrees in a direction towards the outflow port, and this 90 degrees bend imposes an undesirable additional resistance to the outflow fluid flow. Thus in the Bettocchi endoscope an additional outflow fluid resistance is added because the outflow holes are located on a circumferential part of the shaft of the endoscope, while in the system of the present application the outflow hole is located on a cross sectional part of the outflow fluid flow channel and in an end on manner. (4) Side on bubble evacuation: In the Bettochi endoscope a specific air bubble which is initially identified through the telescope is located very far away, up to 1-2 cm from the outflow holes. In light of an already compromised effective outflow rate per hole and in light of an initial far away location of the bubble, it is not possible to predictably evacuate any bubble which the surgeon sees through the telescope. For example, a bubble might be lost in the fluid turbulence while it under takes its large journey of 2 cm. Such method of bubble evacuation wherein the outflow holes are located over the circumferential part of the shaft of the endoscope is being termed as a 'side on bubble evacuation' only for the sake of an easier description. (5) End on bubble evacuation: Unlike the Bettocchi endoscope, in the system of the present application the outflow hole is located at the distal most end of the outflow fluid channel in an end on axial location. In the system of the present application any specific bubble which is seen via telescope can be predictably evacuated in a predictable manner because the bubble is located immediately adjacent and in front of the outflow hole situated at the distal end of the out outflow fluid channel. Such arrangement of bubble evacuation as utilized in the present application is being termed as 'end on bubble evacuation' only for the sake of an easier description. (6) In the Bettocchi endoscope the outflow port is attached at right angle to the long axis of the endoscope. This right angle bend contributes an additional resistance to the outflow fluid flow.
Air bubbles are dangerous since they can cause pulmonary or cardiac air embolism during an endoscopic procedure. Hence in the interest of patient safety the endoscope needs to structurally designed in such a manner that the air bubbles are evacuated in the most efficient manner. In context with evacuating air bubbles, the advantages offered by an endoscope based on the system of the present application versus the Bettocchi endoscope are summarized in the below table:
Bubble evacuation - The Bettocchi endoscope' versus 'The endoscope of the present application
(Table Removed)
An endoscope based on the system of the present application has many structural advantages over the Bettocchi endoscope, as summarized in the below table:
Structural advantages - 'The Bettocchi endoscope' versus 'The endoscope of the present
application

(Table Removed)
Referring to a prior art US Patent 20060041186 (Vancaille et al), a longitudinal protuberance is welded on the inner surface of a solitary housing sheath along the entire long length of the housing sheath. The longitudinal protuberance essentially needs to come into a fluid tight apposition with a component such as the telescope or instrument for the purpose of creating two fluid channels, otherwise the fluid channels do not exist. In this prior art a cradle portion is utilized to support the component such as telescope or instrument, and the 'cradle' undesirably reduces the effective cross sectional area of the endoscope by encroaching upon a part of the valuable cross sectional space which is available inside the lumen of the endoscope. The said 'cradle' can be discarded only by way utilizing an additional longitudinal protuberance, and such arrangement further reduces the available effective cross sectional
area. Let us consider a situation wherein two fluid channels are created by virtue of a single longitudinal protuberance making a fluid tight apposition with a telescope. In such an arrangement it is not possible to contain the endoscopic instrument either totally below or totally above the telescope, and that the instrument could encroach at least partially on to a side of the telescope, and such arrangement could severely jeopardize patient safety by way of an optical illusion or misalignment of the instrument relative to the telescope especially if a thirty degree telescope is used. In US Pat No 20060041186 if the instrument needs to be permanently placed totally below or totally above the telescope then at least two longitudinal protuberance are needed which further undesirably reduces the effective cross section area of the endoscope. In the present application an endoscopic instrument can be placed totally above or below the telescope without reducing the available effective cross sectional area in any manner. Considering a hypothetical endoscope of a some size, in the present application it is possible to allocate a relatively greater area of cross section to the inflow and or the outflow fluid channel in comparison to US Patent 20060041186. An enhanced cross section of the fluid channels translates info a reduced fluid flow resistance which ultimately enhances the evacuation of air bubbles such as produced during bipolar or monopolar surgery. Also a lesser resistance to fluid flow in the inflow fluid flow channel enhances the fluid instillation into the tissue cavity thereby enhancing the mechanical distension of the tissue cavity. Considering a hypothetical endoscope of some size, the advantages of a system based on the present application over US Patent 20060041186 are summarized in the below table:

(Table Removed)
US Patent 7249602 describes a hysteroscopic morcellator based on the continuous flow irrigation principal, and the related product is marketed by Smith & Nephew company. The Smith & Nephew Hysteroscopic Morcellator comprises of an inner sheath which is immovably placed inside an outer sheath. The potential space between the outer and the inner sheath serves as the outflow channel while the inner sheath functions as the inflow channel. The telescope is supported inside an 'optic sleeve' which is provided inside the thickness of
the wall of the inner sheath. A morcellator capable of performing a to and fro and rotary motion is placed in the lumen of the inner sheath. A major disadvantage of this Smith & Nephew Hysteroscopic Morcellator is that the inflow sheath and the optic sleeve undesirably occupy a substantial part of the cross sectional area available inside the endoscope and thereby the size of the morcellator window cannot be relatively increased. The system of the present application makes it possible to discard an inner sheath and also the 'optic sleeve', and a additional cross sectional space achieved thereby can be beneficially utilized for the purpose of increasing the size of a morcellator window. It is the morcellator window which actually comes into contact with the tissue which is morcellated. The Smith & Nephew Hysteroscopic Morcellator has a major drawback of having a relatively smaller morcellator window which reduces patient safety by way of increasing the morcellation time and efficiency. If a hysteroscopic morcellator designed on the principals of the present application then the dimensions of the morcellator window can be relatively increased thereby enhancing morcellation efficiency and patient safety.
For a same outer cross sectional size of the hysteroscopic morcellator, the advantages of a system based on the present application over the Smith & Nephew Hysteroscopic Morcellator are summarized in the below table:
Smith & Nephew Hysteroscopic Hysteroscopic Morcellator based on
Morcellator (US Patent 7249602) the system of the present application
A relatively smaller morcellator window A relatively larger morcellator window
A relatively smaller size of telescope, the A relatively larger size of telescope, the
outflow fluid channel, the inflow fluid outflow fluid channel, the inflow fluid
channel and or the instrument channel and or the instrument
Comprises of an inner sheath placed Comprises of a single housing sheath
inside an outer sheath
A separate inflow tube is essential An separate inflow tube is neither utilized
nor needed
The telescope is supported inside the The telescope is supported primarily over
optic sleeve a rigid sheet
The limitations and disadvantages of conventional and traditional continuous flow irrigation endoscope are apparent to one skilled in the art and hence, there exists a strong need to provide a continuous flow irrigation endoscope which is effective and at the same time, simple to implement.
Objects of the Invention:
A primary object of the present invention is to reduce the size of a continuous flow irrigation endoscope without reducing the size of any or all of the components of the endoscope.
Another objective of the present invention is to increase the size of any or all of the components of a continuous flow irrigation endoscope without increasing the size of endoscope.
Yet another objective of the present invention is to enhance the efficiency of evacuating air bubbles during endoscopic procedures.
Further objective of the present invention is to reduce the resistance to fluid flow offered by the outflow and or inflow fluid flow channel without increasing the outer diameter of the endoscope.
Furthermore objective of the present invention is to increase the size of the telescope and or endoscopic instrument without increasing the size of endoscope.
Summary of the Invention:
The present invention is a system of increasing the effective cross sectional area of continuous flow irrigation endoscopes, wherein the term 'effective cross sectional area' relates to the total cross sectional area which is actually available for being occupied by components such as the telescope, the endoscopic instruments, the inflow fluid channel and the outflow fluid channel.
The present invention is a system of reducing the outer diameter of a continuous flow irrigation endoscope without reducing or reducing the cross sectional size or outer diameter of any one or all of the components such as the telescope, the endoscopic instrument, the inflow fluid channel and the outflow fluid channel. The endoscope related to the present invention comprises of only a single housing sheath only which simultaneously performs the dual function of both, the inflow fluid channel and the outflow fluid channel. The inflow and the outflow fluid flow channels are fluidly separated by a rigid planar sheet whose free
parallel marging along its axial length make a fluid tight approximation or contact with the said single sheath of the endoscope.
The present invention also relates to increasing the cross sectional size or outer diameter of any one or all of the components such as the telescope, the endoscopic instrument, the inflow fluid channel and the outflow fluid channel without increasing the outer diameter of the endoscope. The proposed technology is beneficially utilized in diagnostic endoscopes and operative endoscopes. The proposed technology reduces or minimizes the outer diameter of all kinds of continuous flow irrigation endoscope which includes the conventional endoscopes with a round cross section and also the endoscopes which have a oval like flattish cross section such as the 4 mm and 5 mm Bettochi type of microendoscopes as marketed by Karl Storz.
Brief Description of the Drawings':
Further aspects and advantages of the present invention will be readily understood from the following detailed description with reference to the accompanying drawings. Reference numerals have been used to refer to identical or similar functionally similar elements. The figures together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present invention wherein:
Figure 1 shows a basic functional form of the system of the present invention
Figure 2 shows a housing sheath which has an oval like outer cross section
Figure 3 shows a side view of the basic functional form of the system of the present invention shown in figure 1
Figure 4 shows a side view of the embodiment described in figure 2
Figure 5 specially shows the end cap 32
Figure 6 especially shows the depressed furrows which support the planar sheet
Figure 7 shows a side view of the embodiment described in figure 6 wherein the planar sheet is shown being supported in the longitudinal depressed furrows
Figure 8 describes the 'proximal thickening 16'
Figure 9 shows an embodiment containing a tapered 'proximal thickening'
Figure 10 shows an embodiment containing the 'distal rim 17
Figure 11 shows an embodiment containing the 'proximal thickening' as well as the 'distal rim'
Figure 12 shows an embodiment containing the 'localized thickening 18/19';
Figure 13 shows the telescope installed in the system of figure 1
Figure 14 shows the system of figure 1 wherein a telescope or a instrument is supported by a midline depression in the 'planar sheet'
Figure 15 shows the 'telescopic seal'
Figure 16 shows the 'inner protruding grooves '30 and 31'.
Skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
Detailed Description of the Invention:
While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the
invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the invention as defined by the appended claims.
The Applicants would like to mention that the drawings are drawn to show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by "comprises... a" does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
Accordingly, the present invention relates to a continuous flow irrigation endoscope, comprising: a sheath having peripheral side walls, a proximal end blockable by an end cap and an open distal end defining a longitudinal cavity; a planar bifurcating member dividing the longitudinally extending cavity defined by the sheath into two fluid flow channels; a circumferential portion of the sheath being provided with an inlet port at about the proximal end thereof such that the inlet port communicates with one of the two fluid flow channels; and said circumferential portion of the sheath being provided with an outlet port at about the proximal end thereof such that the outlet port communicates with the other fluid flow channel.
In an embodiment of the present invention, wherein the said planar bifurcating member is a rigid rectangular sheet.
In another embodiment of the present invention, wherein the said planar bifurcating member is a rigid rectangular sheet having depressed groove/furrow at about central location and along an entire long length of the rectangular sheet.
In yet another embodiment of the present invention, wherein the said sheath has a round/circular cross section.
In still another embodiment of the present invention, wherein the said sheath has an oval like cross section.
In a further embodiment of the present invention, wherein the planar bifurcating member is welded to the inner surface of the sheath wall at atleast two points.
In a furthermore embodiment of the present invention, wherein the entire longitudinal cavity defined by the sheath has a same uniform sectional shape and size.
In one more embodiment of the present invention, wherein the planar bifurcating member is slidably supported inside two axially aligned furrows/depressions provided in the inner surface of the wall of the said sheath, the said furrows/depressions being parallel to each other and to the long axis of the said sheath.
In an embodiment of the present invention, wherein a distal end of the said sheath is devoid of the said furrows/depressions
In yet another embodiment of the present invention, wherein the entire circumference of a proximal length of the sheath is made thicker relative to the rest of distal length of the sheath.
In still another embodiment of the present invention, wherein a part of the sheath wall immediately adjacent and external to one or both furrows/depressions is additionally thickened in the form of outward indentation
In a further embodiment of the present invention, wherein the said outward indentation is provided on a part or the entire length of one or both the furrows/depressions.
In a furthermore embodiment of the present invention, wherein the planar bifurcating member is slidably supported inside two axially aligned furrows/depressions provided on the inner surface of the wall of the said sheath; each of the said furrow/depression being formed
between two closely spaced parallel indentations/ridges arising from the inner surface of the sheath.
In one more embodiment of the present invention, wherein the two fluid channels are configured to allow insertion of a telescope and/ or an operating instrument.
In an embodiment of the present invention, wherein first of the said fluid channel is configured occupied to allow insertion of a telescope and the second of the said fluid channel is configured to allow the insertion of an operating instrument.
In another embodiment of the present invention, wherein the end cap has provisions to allow entry of the telescope and or the operating instrument into fluid channel(s).
In yet embodiment of the present invention, wherein the telescope and or the operating instrument has a bent portion and the said bent portion is situated outside the end cap.
In still embodiment of the present invention, wherein the circumferential portion of the sheath has provisions to allow entry of the telescope and or the operating instrument into fluid channel(s).
In a further embodiment of the present invention, wherein the telescope and or the endoscopic operating instrument has a bent portion and the said bent portion is situated inside the lumen of a fluid channel(s).
Let us know explain the invention in detail based on the figures.
Figures 1 shows the basic most functional form of the endoscope related to the system of the present invention. The continuous flow irrigation endoscope 7 comprises of a housing sheath 1 and a planar sheet 2 which extends longitudinally inside the lumen of the housing sheath 1. The housing sheath 1 is shown having a round cross section. The planar sheet 2 divides the lumen of sheath 1 into two fluid flow channels 3 and 4. One fluid channel functions as the inflow channel while the other serves as the outflow channel.
Figure 2 is similar to figure 1 except that the housing sheath 1 has an oval like cross section.
Figure 3 shows a side view of the endoscope 7 described in figure 1. The planar sheet 2 divides the lumen of the housing sheath 1 into two longitudinal fluid channels 3 and 4. The endoscope 7 has a proximal end 9 which is essentially located near the surgeon during surgery and a distal end 8 which enters into the body tissue cavity. Two ports 5 and 6 are shown permanently attached over the circumferential part of sheath 1 at the proximal end 9, and each port communicates with a fluid channel. For the sake of an academic discussion let ports 6 and 5 be arbitrarily assumed to be the inflow and the outflow ports respectively. An inflow tube and an outflow waste removing tube, not shown in the diagrams, are connectable to the inflow and outflow ports respectively for instilling and removing fluid from a body tissue cavity which is not drawn in any figures. Pressurized sterile irrigation fluid which is instilled into the inflow port 6 travels in the inflow channel 3 in the direction of arrow 10 to enter into a body tissue cavity via inflow opening 12. The waste fluid present inside the body tissue cavity enters into the outflow channel 4 via the outflow opening 13 and thereafter this waste fluid moves in the direction of arrow 11 to be finally evacuated via the outflow port 5. The openings 12 and 13 are located at the distal most ends of the inflow and outflow fluid channels and such a locational placement of the openings 12 and 13 is being arbitrarily termed as 'end on placement'. The 'end on placement' promotes the evacuation of dangerous air bubbles by minimizing fluid resistance and it also promotes cavity distension. The function of the ports 5 and 6 could also be interchanged in accordance with a structural or functional requirement but in such a case the described preceding sequence of events would need to be accordingly reversed. The ports 6 and 5 are shown attached at right over the outer circumferential surface of the sheath 1. However the right angle bend offers an additional undesirable resistance to fluid flow hence the ports could also be attached obliquely making an acute angle with the long axis of the endoscope.
Figure 4 shows a side view of the endoscope 7 described in figure 2 and a related discussion to the same would be similar to the description contained in the preceding paragraph as in context with an endoscope having a round cross section.
Referring to figure 1 the round cross section can be used in all the procedures such as hysteroscopic, urologic and arthroscopic procedures. While the oval like cross section shown in figure 2 is used optionally and relatively less frequently in specific surgical situations only. It is important to note that all procedures performed by the oval cross section can also be
performed by the round cross section. Some surgeon's might prefer to use the oval like cross section in office hysteroscopy in a conscious patient. While it may not be advisable to use the oval cross section in urology since it could traumatize the urethera.
Referring to figures 1 to 4 the planar sheet 2 could be shifted either up or down between the 12'0 clock and the 6'0 clock location of the housing sheath 1, and in this manner the cross sectional size of both fluid channels could be varied relative to each other. For example the cross sectional area of the outflow fluid channel could be increased relative to the inflow fluid channel, and vise versa, and that both of these embodiments have associated merits and demerits. Let us hypothetically assume a situation wherein the outflow fluid channel has a larger cross section than the inflow channel. Such a situation promotes the evacuation of dangerous air bubbles by reducing the outflow fluid resistance. Again assuming a hypothetical situation wherein the inflow fluid channel has a smaller cross section relative to the outflow channel, in such situation the inflow jet emerging out of the distal opening a inflow fluid channel travels to a relatively greater distance inside the body tissue cavity thereby substantially isolating the inflow fluid stream from the outflow fluid flow stream.
In the present invention a telescope and or an operating instrument could be placed in any fluid channel. Alternatively stating the telescope and the instrument could be housed in the same or separate fluid flow channels. It should be noted that the said instrument is a flexible scissor, flexible forceps, bipolar wire electrode, monopolar wire electrode, a morcellator, a shaver, a simple probe.
It could be relatively beneficial to place the telescope in the inflow channel since a constant supply of clear irrigation fluid helps in maintaining a clear view in front of the tip of the telescope.
It could be relatively beneficial to place a 30 degree telescope in a superiorly located channel such as 3 since such telescope views in a forward and downward direction. Accordingly, in such situation it would be further beneficial to place the instrument in an inferior channel such as 4. With a zero degree telescope the endoscopic instrument could be placed in the same or a separate fluid flow channel because a zero degree telescope views in a straight end on manner.
Referring to figure 1 to 4, the proximal end 9 of the endoscope 7 appears to be open but that is not the case since the proximal end 9 is deemed to be blocked in a fluid tight manner by suitable mechanical means which we arbitrarily term as 'end cap'. The end cap is a rigid structure whose primary function is to block both fluid channels at the proximal end 9 such that no irrigation fluid leaks from the proximal end 9. The end cap could be additionally used to pass telescope and or instrument into the fluid channel/s in a fluid tight manner such that no fluid leaks by the sides of the instrument or the telescope after the same are passed through the end cap. The end cap is so designed that it provides at least a partial support to the telescope and or the instrument at their respective proximal ends. The end cap is not welded to the planar sheet 2 or to the housing sheath 1. The endoscope 7 cannot function unless the end cap is installed at the proximal end 9. The said end cap 32 is shown in figure S and the two holes 33 and 34 are meant to provide passage to the instrument and or the telescope. The end cap 32 also exists and functions without the holes 33 and 34 in case the instrument and telescope are not utilized at all, or if the telescope and or the instrument are passed directly through the circumferential part of the endoscope 7. Referring to the end cap 32 the arrow 35 signifies that the end cap is connectable to the proximal end 9.
As already described, the telescope and or the endoscopic instrument occupy any or both fluid channels. As regards the insertion of the telescope and or the instrument the same could be inserted either through the end cap or through the circumferential part of the wall of the housing sheath 1. Both these embodiments are important and need to be considered with equal emphasis. The telescope and or the endoscopic instrument could also contain a bend located near a proximal location of the same. Depending upon the chosen embodiment said 'bend' could be located either outside the end cap or inside the lumen of a fluid channel. Many permutation combinations are possible in context with the said bend. For example a straight telescope could be passed through the end cap into an upper fluid channel such as 3 and flexible instrument could also be passed through the end cap into an inferiorly placed fluid channel such as 4 with the bend of the said instrument being located outside the end cap. Alternatively, a straight telescope could be passed through the end cap into an upper fluid channel such as 3 and flexible instrument could inserted through the circumferential part of the wall of the housing sheath 1 into an inferiorly placed fluid channel such as 4 with the bend of the said instrument being located outside the housing sheath 1. In case the instrument was a morcellator or a shaver then such instrument without any bend could be passed through the end cap into the inferior fluid channel 4, while a bent telescope could be directly inserted
into the upper fluid channel 3 through a hole in the circumferential part of the wall of the housing sheath overlying the upper fluid channel 3 or that the bent telescope could be passed through the end cap into the upper fluid channel 3 with the said 'bend' being located outside the end cap.
The planar sheet 2 is a flattish kind of a two dimensional object having a fixed length and a width, and that the length and width of the planar sheet 2 are chosen in accordance with the inner dimensions of the housing sheath 1. The planar sheet 2 can also be described as an axially oriented two dimensional structure which can be divided into two adjacent symmetrical halves by an imaginary line which runs along its central long axis, and that the said 'two adjacent symmetrical halves' being mirror images of each other. A basic most functional form of the planar sheet 2 is a flat rectangular sheet. However as an optional embodiment, as shown later in figure 14 a linear depression could also be provided in the centre of the entire long length of the planar sheet 2 for the purpose of providing additional support to a telescope or a instrument. The present application fully functions without the said longitudinal depression and that the said longitudinal depression also tends to reduce the effective cross sectional area by way of encroaching upon a part of the available cross section inside the lumen of the housing sheath 1.
The planar sheet 2 is either permanently welded to sheath 1 or it is detachably housed inside sheath 1. Alternatively stating, the free parallel margins of the planar sheet 2 are either permanently welded to the inner surface of the housing sheath 1, or that the free parallel margins of the planar sheet 2 make a fluid tight apposition with the inner surface of the wall of sheath 1, and both these embodiments have equal merits and demerits from a surgical point of view. For example, permanently welding the planar sheet 2 to the inner surface of sheath 1 could provide additional mechanical strength however it could also makes it relatively more difficult to clean the inner lumen of the sheath 1. Also, detachably installing the planar sheet 2 inside the sheath 1 could make it relatively easier to clean the lumen of sheath 1, but at the same time it could relatively reduce the overall mechanical strength of the planar sheet 2. Both these arrangements being equally important need to be included with an equal emphasis. It also needs to be noted that in case the planar sheet is detachably installed then in such a case from a practical point of view there could be a minimal fluid communication between the two fluid flow channels.
In case the planar sheet 2 is detachably installed inside sheath 1 then the planar sheet 2 could be inserted into the housing sheath 1 immediately prior to each surgery and could be removed immediately after the surgery. Such arrangement could facilitate the cleaning of the lumen of the sheath 1. However such arrangement is at the discretion of the surgeon and that multiple surgeries may be done without removing the planar sheet 2.
Referring to figures 1 to 4 an obturator could be inserted into the lumen of the endoscope 7, and thereafter the endoscope 7 with the installed obturator could be inserted into the opening of a body tissue cavity. Those conversant in the art would understand that a conventional 'obturator' relates to a long solid cylinder like object having a blunt distal end which minimizes any tissue trauma while inserting the 'obturator-endoscope' assembly into a tissue cavity. Whether or not an obturator is used is the sole discretion of the surgeon. Many surgeons may not use an obturator especially with small size endoscopes while other surgeons might always like to use an obturator. If an obturator is used in the present application then the end cap » would need to be removed prior to inserting the obturator inside the housing sheath 1. After the 'obturator-endoscope' system is inserted into a body tissue cavity the obturator is removed and the end cap is connected in a fluid tight manner to the proximal end 9. Hence the end cap can only be connectable to the proximal end 9 and that the end cap cannot be permanently welded to the proximal end 9. Referring to the present application a major distal part of the obturator would need to have a flat empty groove for accommodating the planar sheet 2 when the obturator is being inserted into the system shown in figures 1 to 4. It is obviously clear that an obturator is inserted only after the planar sheet 2 has been installed inside the housing sheath 1. The said obturator is not shown in any of the figures only to keep the drawings simple.
The planar sheet 2 is either permanently welded to the inner surface sheath 1 or it is detachably housed inside the lumen of sheath 1. In case the planar sheet 2 is welded to the inner wall of the sheath 1 then no additional support needs to be provided between the planar sheet 2 and the sheath 1. Considering a situation wherein the planar sheet 2 is detachably installed inside sheath 1, such a system does function if the planar sheet 2 is merely placed inside the housing sheath 1 without any additional support being derived from sheath 1, however according to the discretion of the surgeon an additional support could also be derived from the inner luminal surface of sheath 1. Referring to figure 1 let it be assumed that the planar sheet 2 having a width less than the inner diameter of the sheath 1 is merely placed
inside housing sheath 1, and that in such a situation the planar sheet 2 would obviously fall down under the influence of gravity. Hypothetically, if in such a situation the width of the planar sheet 2 is made equal to the inner diameter of the sheath 1 or if an adequately sized instrument is placed under the planar sheet 2 in the inferior channel 4 or if the same planar sheet 2 which has a smaller width than the inner diameter of the sheath 1 is placed adjacent to the 6'0 clock location, then the planar sheet 2 would not fall down, and in such a situation the planar sheet 2 would also be able to rotate along its long axis, and such arrangement could be beneficially used in certain selected surgical procedures, in case desired by the surgeon. However in case the surgeon so desires then additional mechanical support could also be provided to the planar sheet 2 as shown in figures 6 and 7. Figures 6 and 7 are similar to figures 1 and 3 except that the wall 1 of the housing sheath is represented by two concentric lines representing a thickness related to the wall of the sheath 1. Referring to figures 6 and 7, the said 'additional mechanical support' is provided by two depressed furrows 14 and 15 which exist in the form of longitudinal grooves structurally provided in the inner side of the thickness of the wall of sheath 1 by being etched into the same. The parallel free axial margins of planar sheet 2 are slidably placed in the furrows 14 and 15. As more clearly shown in figure 7 the depressed furrows 14 and 15 are two linear depressions in the wall of sheath 1 and that the depressed furrows run parallel to the long axis of sheath 1. The depressed furrows 14 and 15 could cause a mechanical weakness in the wall of the housing sheath 1. In case the said mechanical weakness is only minimal then such system could be used in surgical procedures as such. However if the acquired structural weakness in the housing sheath wall is not acceptable then additional external reinforcement could be provided to strengthen the weakened sheath 1 by incorporating any or all of the below described four structural arrangements, as follows:
Structural arrangement 1 - 'Proximal thickening' 16: Referring to figure 7 the depressed furrows 14 and 15 could reduce the mechanical strength of sheath 1. Increasing the overall wall thickness of sheath 1 is not desirable since the same increases the size of the endoscope. Referring to figure 8, a 'proximal thickening' is utilized to externally reinforce sheath 1. The term 'proximal thickening' refers to a structural arrangement wherein the wall thickness of the entire circumference of a proximal minimal length of sheath 1 is made relatively thicker in comparison to the remaining distal length of sheath 1, such that the lumen of the entire length of the housing sheath 1 remains unchanged in terms of a cross sectional size and shape. The 'proximal thickening' imparts additional mechanical strength to the distal length of the sheath
1 whose walls have been weakened by the depressed furrows 14 and 15. Referring to figure 8 the said circumferential 'proximal thickening' is represented by two thick black shaded lines 16. A cross sectional view through the 'proximal thickening' is not separately shown only to keep the drawings simple. The 'proximal thickening' 16 could extend to a short minimal distance beyond the ports 6 and 5 in the direction of the distal open end 8. The 'proximal thickening' as shown in figure 8 is confined to a small proximal length of the sheath 1 which usually does not enter into a body tissue cavity. However keeping in mind a remote possibility of the 'proximal thickening' entering into the body tissue cavity, the 'proximal thickening' could be imparted a tapering shape as shown in figure 9. The actual additional thickening of the sheath wall in the region of the 'proximal thickening' 16 is decided in accordance with the additional mechanical strength which needs to be provided to the distal weakened shaft of sheath 1.
Structural arrangement 2 - 'Distal rim' 17: Another method of strengthening the sheath 1 is by providing a 'distal rim' 17 as shown in figure 10. The term 'distal rim' relates to a structural arrangement wherein a distal most length of the sheath 1 is devoid of the depressed furrows 14 and 15 as shown in figure 10. The distal rim 17 indirectly provides additional mechanical strength to a weakened entire proximal length of the sheath 1. If the 'distal rim' is incorporated then the length of the planar sheet 2 obviously needs to be shortened accordingly, and keeping the same in mind it is recommended that the 'length of the distal rim' be chosen as short as possible. The term 'length of the distal rim' obviously refers to a length along the long axis of the sheath 1. The length of the 'distal rim' could be chosen in accordance to the additional mechanical strength which is required to be provided to the weakened proximal length of the sheath 1 which still harbors the depressed furrows 14 and 15.
Structural arrangement 3 - 'Dual strengthening of sheath 1': The 'proximal thickening' 16 and 'distal rim' 17, both these provisions can also be simultaneously incorporated for an enhanced strengthening, as shown in figure 11.
Structural arrangement 4 - 'Localized thickening 18/19': Referring to figure 12 another method to strengthen the sheath 1 is by applying a 'localized thickening' 18/19 over a limited part of the wall of sheath 1 which has been weakened by the furrows 14 and 15. The term 'localized thickening' relates to a structural arrangement wherein a minimal surface area of
the sheath wall 1 immediately adjacent and external to the furrows 14 and IS is made relatively thicker relative to the rest of the sheath wall as shown in figure 11. The said 'localized thickening' could be small dot shaped thickenings immediately overlying the furrows 14 and 15 or a narrow axially oriented strip of the sheath wall immediately overlying the furrows 14 and 15 could be thickened relative to the rest of the sheath wall. The 'localized thickening' 18 and 19 could be small dot shaped circular like external indentations overlying the furrows 14 and 15. The diameter of each circular 'localized thickening' needs to be kept as less as possible, such as 0.1 to 2 mm depending upon the depth of the ridges 14 and 15. The additional thickness imparted to the sheath wall in the region of the 'localized thickening' could be equal to or less than the depth of the ridges 14 and 15. In order to minimize a stretch injury to a wound opening it is preferred that no two circular 'localized thickenings' be situated diametrically opposite to each other. Thereby implying that no two circular 'localized thickenings' be located at a same axial location. The number of circular 'localized thickenings' related to each of the furrows 14 and 15 could vary from one to multiple. In case only one circular 'localized thickening' is utilized then the same could be located in the centre of the furrow in order to impart an equitable strength in a distal and a proximal direction. A solitary circular 'localized thickening' could also be located in a relatively more proximal direction in order to minimize the possibility of the circular 'localized thickening' to enter into a wound opening. The 'localized thickening' could also extend longitudinally along a partial or the entire length of the sheath 1 overlying the furrows 14 and 15, and the cross section of such longitudinal 'localized thickening' obviously being hemi cylinder type in axial cross section. The longitudinally oriented 'localized thickening' could also be confined to only one furrow, 14 or 15.
Referring to figure 13 a telescope 20 is shown to be placed inside the fluid channel 3. At the proximal end the telescope 20 derives support from an end cap not shown in this drawing and distally the telescope 20 is supported over the planar sheet 2. Unlike Bettocchi Hysteroscopes of Karl Storz the telescope 20 in not placed inside an 'optic sleeve'. The optic sleeve is a major disadvantage since it undesirably reduces the effective cross sectional area of the endoscope lumen. Depending upon its diameter the telescope 20 could also touch the inner surface of the housing sheath 1 at the 12'O clock location, however such arrangement should not be misinterpreted as if the telescope contributes in creating a fluid channel in any manner. Also such arrangement should also not be misinterpreted as if the telescope 20 sub divides the channel 3 into two sub channels because at the proximal end the two sub channels, if at
all, is supplied by the same common inflow port. Thus from a structural point of view a channel such as 3 needs to considered as a single channel irrespective of the fact whether the same is occupied by a telescope or instrument. Referring to figure 13 the telescope could also be substituted by an endoscopic instrument.
Referring to figure 14 the telescope 20 is additionally supported inside a axially oriented curved depression provided in the centre of the planar sheet 2 and that the depression involves the entire central part of the of the planar sheet 2 along its axial length. Referring to this figure 14 the telescope could also be substituted by an endoscopic instrument. The said curved depression shown in figure 14 has a disadvantage that it reduces the effective cross sectional area of the endoscope. The present invention fully functions even without the said 'depression'.
The 'telescope seal' 21: Referring to figure 13 let channels 3 and 4 be arbitrarily assumed to be the inflow and the outflow fluid channels respectively. It could be argued that the distal open ends 12 and 13 of the channels 3 and 4 being located adjacent to each other could cause a partial mixing of the inflow and the outflow fluid streams. Such problem could be substantially minimized by reducing the cross section of the inflow channel 3 in comparison to the cross section of the outflow channel 4. Such arrangement allows the inflow fluid jet to emerge from the inflow channel 3 with a relatively greater velocity and thereby traverse a relatively larger distance inside a tissue cavity, while the outflow channel having a larger area of cross section would suck waste fluid from only a nearby adjacent location. Thereby implying that in figure 13 the two fluid channels appear to be located adjacent to each other however from a functional point of view, as just explained, the two fluid channels function as if their distal open ends 12 and 13 were located far away distance from each other. Let us consider a situation wherein despite the preceding solution and explanation a surgeon still wishes to locate the distal openings ends 12 and 13 at a far away distance from each other, and the same could be accomplished by a 'telescope seal'. Wherein the term 'telescope seal' relates to a flat rigid hemi spherical like sheet having a central hole for inserting the telescope. Referring to figure 15S the hemispherical black shaded area 21 represents the said 'telescope seal'. The 'telescope seal' 21 is a flat rigid sheet whose circular like free margin confirms to the shape of partial inner cross section of the fluid channel 3. The 'telescope seal' 21 is plane which is perpendicular to the telescope 20 and it has a centrally placed hole which is meant to be occupied by the telescope 20 or an instrument. In case the planar sheet 2 is
detachably housed inside the housing sheath 1 then in such a case the lower straight part of the 'telescope seal' 21 could be permanently welded to the planar sheet 2 and that the upper circular like free margin of the 'telescope seal' 21 could remain in a fluid tight apposition with a part of the inner surface of the sheath 1. In case the planar sheet 2 is permanently welded to the housing sheath 1 then in such a case the lower straight part of the 'telescope seal' 21 could be welded to the planar sheet 2, while the upper circular like free margin of the 'telescope seal' 21 could be welded to a part of the inner surface of the sheath 1. In light of the structural arrangement described in context with the telescope seal 21, multiple holes 22 or a single opening is provided in a partial upper circumferential part of the sheath wall proximal to the 'telescope seal' 21. The 'telescope seal' 21 allows any fluid pushed into port 6 to enter into a body tissue cavity only through holes 22 and not through the opening 12. The 'telescope seal' 21 has three drawbacks, that special care needs to be taken while cleaning the endoscope, and it is relatively more difficult to install the telescope into the endoscope and that the circumferentially located holes additionally increase the resistance to fluid flow.
The 'inner protrusions' 30 and 31: The depressed furrows 14 and 15 could also be replaced by two suitable 'inner protruding grooves' 30 and 31 which protrude inwards into the lumen of the sheath 1 as shown in figure 16. The 'inner protrusions' 30 and 31 are welded on diametrically opposite sides of the inner surface of sheath 1, and the protrusions only minimally protrude into the lumen of sheath 1. The groves 30 and 31 are only meant to provide additional support the planar sheet 2. The protrusions 30 and 31 do not generally come in contact with the telescope 20 or an endoscopic instrument, and said 'contact' is also needed. Even if the protrusions 30 and 31 ever come in contact with a telescope or an instrument then such physical contact does not contribute in any manner towards the formation of any fluid flow channel. The 'inner protruding grooves' 30 and 31, however, do tend to undesirably reduce the effective cross sectional area.
Advantage:
The present invention reduces the outer diameter or the outer cross sectional size of a continuous flow irrigation endoscope without reducing the outer cross sectional size or the outer diameter of any or all components such as the fiber optic telescope, the endoscopic instrument, the inflow fluid channel and the outflow fluid channel.
The present invention also allows to increase the outer diameter or the outer cross sectional size any or all components such as the fiber optic telescope, the endoscopic instrument, the inflow fluid channel and the outflow fluid channel of a continuous flow irrigation endoscope without increasing the outer cross sectional size or the outer diameter of the shaft of the endoscope.
The achieved reduction in the size of the endoscope shaft minimizes trauma and pain to the patient, and the achieved increase in the size of the components such as the fiber optic telescope, the endoscopic instrument, the inflow fluid channel and the outflow fluid channel helps in enhancing the surgical efficiency of the endoscope. Hence the present invention is useful to mankind since it enhances patient safety and surgical efficiency related to a continuous flow irrigation endoscope.
The advantages of the disclosed invention are thus attained in an economical, practical, and facile manner. While preferred aspects and example configurations have been shown and described, it is to be understood that various further modifications and additional configurations will be apparent to those skilled in the art. It is intended that the specific embodiments and configurations herein disclosed are illustrative of the preferred nature of the invention, and should not be interpreted as limitations on the scope of the invention.

I/We Claim:
1. A continuous flow irrigation endoscope, comprising:
a sheath having peripheral side walls, a proximal end blockable by an end cap and an
open distal end defining a longitudinal cavity;
a planar bifurcating member dividing the longitudinally extending cavity defined by
the sheath into two fluid flow channels;
a circumferential portion of the sheath being provided with an inlet port at about the
proximal end thereof such that the inlet port communicates with one of the two fluid
flow channels; and
said circumferential portion of the sheath being provided with an outlet port at about
the proximal end thereof such that the outlet port communicates with the other fluid
flow channel.
2. The endoscope as claimed in claim 1, wherein the said planar bifurcating member is a rigid rectangular sheet.
3. The endoscope as claimed in claim 1 wherein the said planar bifurcating member is a rigid rectangular sheet having depressed groove/furrow at about a central location and along an entire long length of the rectangular sheet.
4. The endoscope as claimed in claim 1 wherein the said sheath has a round/circular
cross section.
5. The endoscope as claimed in claim 1 wherein the said sheath has an oval like cross section.
6. The endoscope as claimed in claim 1 wherein the planar bifurcating member is welded to the inner surface of the sheath wall at atleast two points.
7. The endoscope as claimed in claim 1 wherein the entire longitudinal cavity defined by the sheath has a same uniform cross sectional shape and size
8. The endoscope as claimed in claim 1 wherein the planar bifurcating member is slidably supported inside two axially aligned furrows/depressions provided in the inner surface of the wall of the said sheath, the said furrows/depressions being parallel to each other and to the long axis of the said sheath.
9. The endoscope as claimed in claim 8 wherein a distal end of the said sheath is devoid of the said furrows/depressions
10. The endoscope as claimed in claims 8 and 9, wherein the entire circumference of a proximal length of the sheath is made thicker relative to the rest of distal length of the sheath.
11. The endoscope as claimed in claim 8, wherein a part of the sheath wall immediately adjacent and external to one or both furrows/depressions is additionally thickened in the form of outward indentation
12. The endoscope as claimed in claim 11, wherein the said outward indentation is provided on a part or the entire length of one or both the furrows/depressions.
13. The endoscope as claimed in claim 1 wherein the planar bifurcating member is slidably supported inside two axially aligned furrows/depressions provided on the inner surface of the wall of the said sheath; each of the said furrow/depression being formed between two closely spaced parallel indentations/ridges arising from the inner surface of the sheath.
14. The endoscope as claimed in claim 1 wherein the two fluid channels are configured to allow insertion of a telescope and or an operating instrument.
15. The endoscope as claimed in claim 1 wherein a first of the said fluid channel is configured to allow insertion of a telescope and the second of the said fluid channel is configured to allow the insertion of the operating instrument.
16. The endoscope as claimed in claims 14 and 15 wherein the end cap has provisions to allow entry of the telescope and or the operating instrument into fluid channel(s).
17. The endoscope as claimed in claim 16 wherein the telescope and or the operating instrument has a bent portion and the said bent portion is situated outside the end cap.
18. The endoscope as claimed in claims 14 and 15 wherein a circumferential portion of the sheath has provisions to allow entry of the telescope and or the operating instrument enter into fluid channel(s).
19. The endoscope as claimed in claim 18 wherein the telescope and or the operating instrument has a bent portion and the said bent portion is situated inside the lumen of a fluid channel(s).
20. An continuous flow irrigation endoscope substantially as herein described with reference to the accompanying drawings.