Systems and methods for varying stiffness of an endoscopic insertion tube

The specification describes endoscopes that enable varying stiffness of an insertion portion in an endoscope assembly. In one example, an actuator operates either a spring or a flexible tube to vary stiffness of the insertion portion. In alternative examples, an elliptical wheel arrangement or screw mechanism provides a means to increase stiffness of the insertion portion of an endoscope assembly. In further examples, fluid and gas may be used inside the insertion potion to vary stiffness by varying pressure of the fluid/gas.

FIELD

The present specification generally relates to an endoscope unit having an insertion portion whereby the stiffness of the insertion portion can be varied.

BACKGROUND

Endoscopes have attained great acceptance within the medical community, since they provide a means to perform procedures with minimal patient trauma, while enabling the physician to view the internal anatomy of the patient. Over the years, numerous endoscopes have been developed and categorized according to specific applications, such as cystoscopy, colonoscopy, laparoscopy, upper GI endoscopy and others. Endoscopes may be inserted into the body's natural orifices or through an incision in the skin.

An endoscope is usually an elongated tubular shaft, rigid or flexible, having one or more video cameras or fiber optic lens assemblies at its distal end. The shaft is connected to a handle, which sometimes includes an ocular for direct viewing. Viewing is also usually possible via an external screen. Various surgical tools may be inserted through a working channel in the endoscope to perform different surgical procedures.

Endoscopes may have a front camera and a side camera to view the internal organ, such as the colon, illuminators for each camera, one or more fluid injectors to clean the camera lens(es) and sometimes also the illuminator(s) and a working channel to insert surgical tools, for example, to remove polyps found in the colon. Often, endoscopes also have fluid injectors (“jet”) to clean a body cavity, such as the colon, into which they are inserted. The illuminators commonly used are fiber optics which transmit light, generated remotely, to the endoscope tip section. The use of light-emitting diodes (LEDs) for illumination is also known.

The elongated tubular shaft, also known as the insertion portion of the endoscope has a bending section, proximal to a distal end of the shaft that can bend upon application of an external control to navigate a curved path inside a body cavity, or to access difficult areas within the cavity. However, sometimes it is desirable to vary the degree of bending, based on the application or based on the region inside the body cavity where a distal end of the shaft is navigating. A stiffer insertion portion may reduce the chances of looping of the tubular shaft inside the body cavity, whereas a softer insertion portion may make it easier to reach the cecum. Lack of the ability to vary the stiffness of the insertion portion, such as around the bending portion, could result in patient discomfort and/or increased time for endoscopic examinations. Additionally, some physicians may prefer using a stiffer insertion portion, while some others may prefer a flexible insertion portion. Moreover, repeated reprocessing of parts of endoscope, including its cleaning, may influence the flexible characteristics of the insertion portion. As a result, the insertion portion may become more flexible than required with each time it is cleaned.

U.S. Pat. No. 7,789,827, assigned to Storz, discloses “a flexible endoscope comprising: a flexible shaft portion having a distal and a proximal end and including an outer layer comprising an electrically insulated water-tight material, an inner layer enclosed by said outer layer, a plurality of elongated segments disposed in said outer layer and comprising a polymer material that changes characteristics upon the application of an electrical current, a handle portion coupled to said flexible shaft portion, an electrical source for providing the electrical current to said at least one elongated segment, and electrical conductors electrically connected between said plurality of elongated segments and said electrical source, said electrical conductors extending from said flexible shaft portion through said handle portion to said electrical source, wherein said plurality of elongated segments are positioned in said outer layer in an end-to-end fashion along a longitudinal length of said flexible shaft portion and each elongated segment has at least one end affixed to said inner layer such that upon an application of electrical current to said plurality of elongated segments, said plurality of elongated segments change physical dimension, and wherein said inner layer moves relative to said outer layer based on the dimensional change of at least one of said plurality of elongated segments.” However, the '827 patent does not provide a complete mechanical control of the flexibility of the insertion portion.

Thus, what is needed is an insertion portion with an ability to vary its stiffness or flexibility, with minor modifications to the existing structure, shape, size, and manufacturing complexity. Additionally, what is needed is a flexible shaft with an insertion portion that may utilize material available with an endoscope system.

SUMMARY

The present specification discloses various endoscope assemblies comprising an element of variable stiffness embedded within an insertion portion of the endoscope assembly and a controller to vary stiffness of the element.

The present specification discloses an endoscope assembly comprising an insertion portion that is connected to a handle at a proximal end of the insertion portion and a bending portion at a distal end of the insertion portion, comprising: a screw configured to rotate around a longitudinal axis of the endoscope assembly; a housing in physical communication with the screw, wherein the housing is configured to move in a direction that is at least one of a distal direction and a proximal direction along the longitudinal axis of the endoscope assembly, with the rotation of the screw; a stopper placed within the housing; and a wire having a proximal end and a distal end, wherein the proximal end of the wire is connected to the stopper, the wire stretches along a length of the insertion portion, and the distal end of the wire is connected to a proximal end of the bending portion and wherein the wire stiffens the insertion portion upon rotation of the screw towards distal end of the insertion portion.

Optionally, the wire is placed inside a coil fixed to an internal periphery of the insertion portion.

Optionally, the endoscope assembly further comprises a housing containing at least one of the screw, the internal housing, the stopper, and the wire.

Optionally, the endoscope assembly further comprises a knob located in the handle and in physical communication with the screw, wherein a rotation of the knob causes a rotation of the screw.

The stopper may be configured within said housing such that a proximal movement of the housing causes said stopper to move proximally and such that a distal movement of the housing causes the stopper to move distally.

Movement of the wire may cause at least one of the pitch, degree of expansion, degree of compression, and flexibility of the coil to change.

Movement of the wire may cause at least one of the tensile strength, flexibility, or compressibility of the bending portion to change.

Optionally, the housing is positioned around the longitudinal axis of the screw and is configured to move longitudinally along said axis.

The present specification also discloses an endoscope assembly comprising an insertion portion that is connected to a handle at a proximal end of the insertion portion and a bending portion at a distal end of the insertion portion, comprising: an actuator; a spring, having a proximal end and a distal end, wherein the proximal end of the spring is connected to the actuator and wherein the actuator activates the spring; and, a wire, having a proximal end and a distal end, with the proximal end of the wire connected to the distal end of the spring, wherein the wire stretches along a length of the insertion portion and wherein the distal end of the wire is connected to a proximal end of the bending portion, and wherein the wire stiffens the insertion portion upon activation of the spring.

The spring may comprise superelastic material. Optionally, the superelastic material is Nitinol.

Optionally, the actuator is connected to an electric current source that activates the spring. Optionally, the actuator is connected to a heat source that activates the spring. Still optionally, the actuator is connected to a gear motor that activates the spring.

Optionally, the endoscope assembly further comprises a shaft connecting the spring and the wire. The shaft may have a U-shaped structure comprising: a first wall connected to distal end of the spring; and a second wall, parallel to the first wall, connected to the proximal end of the wire.

The wire may be placed inside a coil fixed to an internal periphery of the insertion portion.

Optionally, the endoscope assembly further comprises a housing containing at least one of the actuator, the spring, and the wire.

The present specification also discloses an endoscope assembly comprising an insertion portion that is connected to a handle at a proximal end of the insertion portion and a bending portion at a distal end of the insertion portion, comprising: an actuator; a tube with slits centered and stretching along its longitudinal axis across a portion of its length, the tube having a proximal end and a distal end, wherein the proximal end of the tube is connected to the actuator, and wherein the actuator activates the tube; and, a wire, having a proximal end and a distal end, the proximal end of the wire connected to the tube, wherein the wire stretches along a length of the insertion portion and the distal end of the wire is connected to a proximal end of the bending portion, wherein the wire stiffens the insertion portion upon activation of the tube.

The tube may be manufactured with a superelastic material. Optionally, the superelastic material is Nitinol.

The present specification also discloses an endoscope assembly comprising an insertion portion that is connected to a handle at a proximal end of the insertion portion and a bending portion at a distal end of the insertion portion, comprising: a wheel, approximately shaped as an ellipse, wherein said wheel further comprises a first portion, a second portion, and a center portion; a shaft connected to a center of the wheel; a lever connected to the shaft, wherein rotation of the lever rotates the shaft and the wheel; a wire having a proximal end and a distal end, wherein the proximal end of the wire rests on an edge of the wheel, the wire stretches along a length of the insertion portion and the distal end of the wire is connected to a proximal end of the bending portion and wherein the wire stiffens the insertion portion upon rotation of the wheel; and a stopper connected to the proximal end of the wire, wherein the stopper anchors the wire with the wheel.

Optionally, the wire is placed inside a coil fixed to an internal periphery of the insertion portion.

The present specification also discloses an endoscope assembly comprising a working channel, wherein the outer periphery of the working channel is covered with an enforcement layer providing stiffness to the working channel.

Optionally, the enforcement layer is manufactured from a material comprising at least one metal from family of stainless steel metals.

The present specification also discloses an insertion portion in an endoscope assembly, comprising: at least one flexible tube extending from a proximal end of the insertion portion along length of the insertion portion; a pressure pump connected to the at least one flexible tube at the proximal end of the insertion portion; and a fluid inflating the at least one flexible tube, wherein a pressure of the fluid is controlled by the pressure pump.

Optionally, the fluid is at least one of water, a fluid that changes viscosity based on an applied electric field, a fluid that changes viscosity based on shear rate or shear rate history, a fluid that changes viscosity based on a magnetic field, and a fluid that changes viscosity based on exposure to light.

The fluid may be water sourced from a water supply of the endoscope assembly.

Optionally, varying an operating voltage of the pressure pump controls pressure of the fluid.

A pressure regulator may be connected to the pressure pump to control pressure of the fluid.

Optionally, the at least one flexible tube extending from a proximal end of the insertion portion extends up to a proximal end of bending section of the insertion portion and not into a tip section of the endoscope assembly.

Optionally, the at least one flexible tube extending from a proximal end of the insertion portion extends up to a distal end of the insertion portion.

Still optionally, the at least one flexible tube extending from a proximal end of the insertion portion extends up to an opposite end of the flexible tube, wherein the opposite end is sealed.

The pressure pump may control pressure of the fluid to control flexibility of the at least one flexible tube.

The present specification also discloses an insertion portion in an endoscope assembly, comprising: a flexible tube coiled around an outer circumferential surface of a treatment tool insertion channel embedded inside the insertion portion, the coiled tube extending from a proximal end of the insertion portion along a length of the insertion portion; a pressure pump connected to the flexible tube at the proximal end of the insertion portion; and a fluid inflating the flexible tube, wherein a pressure of the fluid is controlled by the pressure pump.

Optionally, the fluid is at least one of water, a fluid that changes viscosity based on an applied electric field, a fluid that changes viscosity based on shear rate or shear rate history, a fluid that changes viscosity based on a magnetic field, and a fluid that changes viscosity based on exposure to light.

The fluid may be water sourced from a water supply of the endoscope assembly.

Optionally, varying an operating voltage of the pressure pump controls pressure of the fluid.

A pressure regulator may be connected to the pressure pump to control pressure of the fluid.

Optionally, the flexible tube extending from a proximal end of the insertion portion extends up to a proximal end of bending section of the insertion portion and not into said tip section.

Optionally, the flexible tube extending from a proximal end of the insertion portion extends only up to a distal end of the insertion portion.

Still optionally, the flexible tube extending from proximal end of the insertion portion extends up to an opposite end of the flexible tube, wherein the opposite end is sealed.

The pressure pump may control pressure of the fluid to control flexibility of the flexible tube.

The present specification also discloses an insertion portion in an endoscope assembly, comprising: at least one flexible lining stretching along an inner wall of the insertion portion, the flexible lining forming a parallel wall inside the insertion portion such that a gap exists between the parallel wall and the inner wall of the insertion portion, and extending from a proximal end of the insertion portion along a length of the insertion portion; a pressure pump connected to the gap at the proximal end of the insertion portion; and a fluid filling the gap, wherein a pressure of the fluid is controlled by the pressure pump.

The present specification also discloses an insertion portion in an endoscope assembly, comprising: at least one flexible tube extending from a proximal end of the insertion portion along a length of the insertion portion, wherein the flexible tube encloses a gas; at least one sealed chamber into which the at least one flexible tube opens and carries gas into the at least one sealed chamber; and a pressure pump connected to the at least one flexible tube at the proximal end of the insertion portion, wherein a pressure of gas is controlled by the pressure pump.

Optionally, the gas is air.

Optionally, three flexible tubes open into three corresponding sealed chambers.

Each chamber may be located adjacent to one another along a longitudinal axis of the insertion portion.

Each chamber may be concentrically located along a longitudinal axis of the insertion portion.

The aforementioned and other embodiments of the present specification shall be described in greater depth in the drawings and detailed description provided below.

DETAILED DESCRIPTION

The present specification is directed towards multiple embodiments. The following disclosure is provided in order to enable a person having ordinary skill in the art to practice the specification. Language used in this specification should not be interpreted as a general disavowal of any one specific embodiment or used to limit the claims beyond the meaning of the terms used therein. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the specification. Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present specification is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the specification have not been described in detail so as not to unnecessarily obscure the present specification.

It is noted that the term “endoscope” as mentioned to herein may refer particularly to a colonoscope and a gastroscope, according to some embodiments, but is not limited only to colonoscopes and/or gastroscopes. The term “endoscope” may refer to any instrument used to examine the interior of a hollow organ or cavity of the body, provided it further includes an insertion section, bending portion, and viewing tip as described herein.

Reference is now made toFIG. 1, which shows a multiple viewing elements endoscopy system400, in accordance with some embodiments. System400may include a multiple viewing elements endoscope402, having a multiple viewing elements tip section408. Multiple viewing elements endoscope402may include a handle404, from which an elongated shaft406emerges. Elongated shaft406terminates with a tip section408, which can be turned by way of a bending section410. Handle404may be used to maneuver elongated shaft406within a body cavity. The handle404may include one or more knobs and/or switches405that control bending section410as well as functions such as fluid injection and suction. Handle404may further include a working channel opening412through which surgical tools may be inserted, as well as one or more side service channel openings.

A utility cable414may connect between handle404and a main control unit416. Utility cable414may include therein one or more fluid channels and one or more electrical channels. The electrical channel(s) may include at least one data cable to receive video signals from the front and side-pointing viewing elements, as well as at least one power cable to provide electrical power to the viewing elements and to the discrete illuminators. Main control unit416governs a plurality of operational functionalities of the endoscope. For example, main control unit416may govern power transmission to the endoscope's402tip section408, such as for the tip section's viewing elements and illuminators. Main control unit416may further control one or more fluid, liquid and/or suction pump, which supply corresponding functionalities to endoscope402. One or more input devices, such as a keyboard418, may be connected to main control unit416for the purpose of human interaction with main control unit416. In another configuration (not shown), an input device, such as a keyboard, may be integrated with main control unit416in a same casing.

A display420may be connected to main control unit416, and configured to display images and/or video streams received from the viewing elements of multiple viewing elements endoscope402. Display420may further be operative to display a user interface to allow a human operator to set various features of system400.

Optionally, the video streams received from the different viewing elements of multiple viewing elements endoscope402may be displayed separately on display420, either side-by-side or interchangeably (namely, the operator may switch between views from the different viewing elements manually). Alternatively, these video streams may be processed by main control unit416to combine them into a single, panoramic video frame, based on an overlap between fields of view of the viewing elements.

In another configuration (not shown), two or more displays may be connected to main control unit416, each to display a video stream from a different viewing element of the multiple viewing elements endoscope.

Referring now toFIG. 2, a view of a scope handle200of an endoscope, such as endoscope402ofFIG. 1, is shown. Handle200includes various components such as an umbilical tube202that connects its control head to a supply plug at the end of a utility cable, such as utility cable414ofFIG. 1. The control head on handle200includes knobs204to enable turning of a bending section as well as for functions such as fluid injection and suction. Additionally, handle200may include switches/buttons205. Both knobs204and buttons205may provide multiple controlling functions. The figure also shows the position of a working channel opening206through which surgical tools may be inserted. An insertion portion208(shown in part) emerges from handle200, and has been described as elongated shaft406in context ofFIG. 1. For purposes of describing the specification, elongated shaft will be known as the ‘insertion portion’, since it is the part of the endoscope assembly that is inserted inside a body cavity. In embodiments, at a proximal end, handle200connected to insertion portion208maneuvers it within the body cavity.

FIG. 3aillustrates a cross-sectional view of a portion of handle200extending from near working channel opening206towards the beginning of insertion portion208. In embodiments, handle200includes an actuator302that is responsible for activating a spring304, thus allowing the spring304to modulate its degree of elasticity to change its stiffness. In the embodiments of the present specification, activating is defined as being at least one of modifying the pitch, length, degree of compression, or degree of expansion of the spring. In various embodiments, the spring is any one of a tension/extension spring, compression spring, constant spring, variable spring, coil spring, flat spring, machined spring, In embodiments, actuator302and spring304are manufactured with Nitinol. Nitinol is an alloy of Nickel and Titanium, and is known for its properties of shape memory and super elasticity. Nitinol deforms at low temperatures and recovers its original shape when heated. In embodiments, this property is used to control or vary the stiffness of insertion portion208.

In embodiments, a first end of a wire306is connected to a shaft over which spring304is wound, inside a housing. In the embodiments of the present specification, a wire comprises any single, cylindrical, flexible strand or rod of metal or any member capable of having its extent or degree of mechanical load bearing be modulated. Movement of spring304influences stiffness of wire306. A second end of wire306may be connected to a proximal end of a bending section within insertion portion208. Therefore, movement of spring304influences the stiffness of insertion portion208along its entire length. In embodiments, a coil308is wound around wire306to protect it and enable movement of wire306. In the embodiments of the present specification, movement of the wire causes at least one of the pitch, degree of expansion, degree of compression, and flexibility of the coil to change. In addition, in the embodiments of the present specification, movement of the wire causes at least one of the tensile strength, flexibility, or compressibility of the bending section of the endoscope to change.

Referring now toFIG. 3b, another cross-sectional view of spring304and related arrangements is illustrated in accordance with some embodiments. A housing310accommodates spring304and a dynamic shaft316. Housing310stretches across the length of spring304, and has two ends—a proximal end318and a distal end320, which may be proximal and distal respectively to a beginning of the handle of the endoscope. Shaft316is connected to a distal end of actuator302inside housing310. The proximal end of actuator302may continuously exit housing310towards a source of energy that actuates spring's304movements. Spring304is wound around a tubular length of actuator302, positioned inside housing310. A proximal end of spring304is fixed to the internal surface of proximal end318of housing310. A distal end of spring304is fixed to shaft316.

In one embodiment, shaft316is a U-shaped structure, where the two straight parallel edges of its U-shape may be referred to as a first wall324and a second wall322, positioned parallel to one another, each having internal and external surfaces. First and second walls324,322, may be connected to each other with a flat base323completing the U-shaped form. Wall324, which is on the proximal side, connects to spring304on its external surface, while wall322on the distal side, is pierced by, or generally attached to, wire306. Wire306enters shaft316from the external surface of wall322and is held in place by a stopper312on the other side of wall322. Thus, stopper312aids in anchoring of wire306inside housing310. The distal end of wire306continuously exits distal end320of housing310, opposite to the side where actuator302exits housing310. Outside housing310, wire306is protected by coil308that is fixed to the internal surface of the insertion portion.

Referring now toFIGS. 4a, 4b, 4c, and 4d, exemplary embodiments of energy sources for an actuator, such as actuator302, are illustrated.FIG. 4aillustrates an actuator402that may be energized by an electric current. In embodiments, actuator402may comprise two parallel terminals402aand402bthat are connected to each end of spring490. In an embodiment, terminal402ais connected to proximal end of spring490, and terminal402bis connected to distal end of spring490. Any one of the two terminals may be connected to an anode, while the other is connected to a cathode. Electric current may pass through the two terminals, resulting in activation of spring490, thus allowing spring490to modulate its degree of elasticity to change its stiffness. In embodiments, actuator402and spring490are manufactured with Nitinol. Nitinol is an alloy of Nickel and Titanium, and is known for its properties of shape memory and superelasticity, namely an elastic, reversible response to applied stress. Nitinol deforms at low temperatures and recovers its original shape when heated or placed at low temperatures. Electric current passing through the two terminals heat actuator402and as a result spring490is also heated, thereby contracting spring490, resulting in increased stiffness of a wire496. The second end of wire496, connected to the proximal end of the bending section within the insertion portion, therefore increases the stiffness of the insertion portion along its entire length. In embodiments, property of superelasticity is used to control or vary the stiffness of the insertion portion.

FIG. 4billustrates an actuator491that may be energized by a heating body or heat source, such as but not limited to resistance based heater. Actuator491is heated, due to thermal conductivity and/or heat transfer from the heating body or heat source. Thus, actuator491may be a heat body connected to a spring493along the length of the shaft over which spring493is wound. In embodiments, heating the actuator491activates spring493, which may be manufactured from a super-elastic material such as Nitinol. Temperature changes applied on the two terminals of heat actuator491also causes spring493to be heated, thereby causing spring493to be in a first configuration, or its original shape, which results in an increase in the stiffness of the insertion portion via pulling or stretching of wire496. In embodiments, the superelastic property is used to control or vary the stiffness of the insertion portion.

In another embodiment, reduction of temperature of actuator491and therefore that of spring493results in deformation of both (due to Nitinol deforming at low temperatures), owing to their superelastic property. As a result, lowering the temperature of actuator491in order to cool it results in spring493to be brought to a second configuration, which causes contraction of wire496and subsequently, an increase in the stiffness of the insertion portion. In embodiments, a coolant is used to cool actuator491and spring493.

The extent of stiffness of the insertion tube is therefore controlled by changing temperature of the structure, and therefore of the properties of the wire496, such that the wire is either pushed or contracted or pulled or expanded.

In yet another embodiment,FIGS. 4cand 4dillustrate a gear motor494that drives a dynamic shaft495connected to a wire496placed inside the endoscope's insertion portion. In one embodiment, shaft495is a U-shaped structure, where the two straight parallel edges of its U-shape may be referred to as a first wall498and a second wall499, positioned parallel to one another, each having internal and external surfaces. First and second walls498,499may be connected to each other with a flat base419, thus completing the U-shape. Wire496stretches over the complete length of the insertion portion and is connected to shaft495at proximal end of wire496. First wall498of shaft495is connected to wire496while a proximal end of second wall499is connected to an actuator497driven by gear motor494. In embodiments, operation of gear motor494results in stiffening or relaxing of wire496with backward or forward movements of shaft495, respectively, that is pulled by gear motor494.

Referring now toFIG. 5a, another cross-sectional view of spring304and related arrangements described in context ofFIGS. 3a-3band 4a-4dis illustrated in accordance with some embodiments. Embodiments ofFIGS. 4aand 4binclude wire, coil, and housing configurations (not labelled) similar to those described in context ofFIGS. 3aand 3b. Hereinafter, wire306coil308, housing310, and distal end320of housing310, also refer to similar configurations described forFIGS. 4aand 4b. In embodiments, coil308is wound around wire306to protect it and enable movement of wire306. An arrow502illustrates an exemplary direction of movement of spring304. Movement in one direction may stretch spring304, such that spring304lengthens. As a result, wire306also relaxes and decreases the stiffness of the insertion portion, which may make the insertion portion more flexible. Movement in an opposite direction may tighten spring304, resulting in a tightening of wire306and an increase in the stiffness of the insertion portion. Actuator302, also described above with respect toFIGS. 4a-4d, causes movement of spring304. An energized actuator302may activate spring304, which results in the tightening of spring304. Alternatively, when the energy is not provided to actuator302, or its source is interrupted, spring304may return to a loosened or stretched state. While actuator302may energize and activate a Nitinol spring causing it to stiffen, in certain embodiments utilizing a mechanical means to move actuator302may similarly stiffen or deform spring304by a mechanical movement. In embodiments, wire306is placed inside coil308, which is positioned outside of housing310. Coil308is fixed to an internal surface of the insertion portion along its length, and is also fixed to an external surface of distal end320of housing310. As a result, when spring304is stiffened, wire306is pulled, resulting from the pulling motion by actuator302.

In operation, as actuator302is energized, spring304is activated. Activation of spring304results in a change in its shape owing to superelastic properties of Nitinol. Consequently, dynamic shaft316moves while pulling or pushing wire306, as wire306is also connected to shaft316. The stiffness character of the insertion portion is influenced by pulling or pushing the wire, influenced respectively by heating or cooling actuator302. In embodiments, controlling the amount of energy provided to actuator302may further control the degree of stiffness of the insertion portion. In embodiments, a controller to control the degree of energy provided to actuator302and therefore the degree of stiffness of the insertion portion is provided in either the handle of the endoscope, the main control unit connected to the endoscope, through a foot pedal attached to the endoscope, or through any other means. The control mechanism may be provided through an interface such as a push button, a valve, a nob, or any other digital or analogue interface. As the energy provided to actuator302is increased, wire306is pulled more, and the degree of stiffness increases. In embodiments, one or more screens connected to the system may display the use of a control to control the stiffness, and may even display a degree of stiffness achieved through the control. For example a display may illustrate the stiffness in effect through a binary illustration, such as whether the insertion tube is or is not stiff. In another example, a display may indicate a degree of stiffness over a numerical or any other scale, such as 1 to 4, where 1 may be first degree of stiffness and 4 may be the highest degree of stiffness that can be applied to the insertion tube, or vice versa. In yet another example, also illustrated inFIG. 5b, a degree of stiffness may be indicated through a display506by means of a slider501between standard “+” and “−” symbols503and504, respectively indicating maximum and minimum degrees of stiffness.

FIG. 6illustrates an alternative embodiment of an arrangement to manipulate and vary the stiffness of an insertion portion in an endoscope. In this embodiment, the spring is replaced by a tube604, which is also manufactured with Nitinol. Tube604comprises slits605along its tubular walls, and along its longitudinal axis. The slits605may stretch across a portion of tube604and may be centered at the center of the total length of tube604. In embodiments, the slits605are typically equidistant from each other, spaced throughout the circumference of tube604. Similar to the previous embodiment, tube604may be placed over an actuator602, inside a housing610. Housing610accommodates tube604and a dynamic shaft616. Housing610may stretch across the length of tube604, and have two ends—a proximal end618and a distal end620, which may be proximal and distal respectively to a beginning of the handle of the endoscope. Shaft616may be connected to a distal end of actuator602inside housing610. The proximal end of actuator602may continuously exit housing610towards a source of energy that actuates tube's604movements. Tube604may be placed around a tubular length of actuator602, positioned inside housing610. Proximal end of tube604is fixed to internal surface of proximal end618of housing610. Distal end of tube604is fixed to shaft616.

In one embodiment, shaft616is a U-shaped structure, where the two straight parallel edges of its U-shape may be referred to as a first wall624and a second wall622, positioned parallel to one another, each having internal and external surfaces. First and second walls624,622, may be connected to each other with a flat base623, thus completing the U-shape. External surface of wall624, which is on the proximal side of the endoscope handle, connects to tube604, while wall622on the distal side, is pierced by wire606. Wire606enters shaft616from the external surface of wall622and is held in place by a stopper612on the other side of wall622. Thus, stopper612aids in anchoring of wire606within the inside of housing610. The distal end of wire606continuously exits distal end620of housing610, opposite to the side where actuator602exits housing610. Outside housing610, a coil608that is fixed to the internal surface of insertion portion208protects wire606. An arrow614illustrates exemplary direction of movement of tube604, which is caused by energising or de-energising of actuator602. Actuator602may be one of several embodiments described previously, such as in context ofFIGS. 4a, 4b, 4c, and 4d. Additionally, operation of tube604mechanism may be similar to operation of spring304mechanism, similar to that described in context ofFIG. 5a.

FIG. 7aillustrates a portion of an endoscope handle with an elliptical wheel mechanism700that enables variable stiffness of an insertion portion708of the endoscope. In an embodiment, an elliptical wheel704comprises two side portions—a first side portion716and a second side portion718that sandwich a center portion. The edges of first portion716and second portion718rest slightly above the center portion of the sandwich. Thus, the diameter of first portion716and second portion718is larger than the diameter of the center portion. In embodiments, a wire702rests on an outer edge of the center portion, between two sides716and718of wheel704. In embodiments, wire702is connected at its proximal end to a stopper714. Stopper714rests against edges two sides716and718of wheel704. Wheel704may have a shape similar to that of an ellipse. In embodiments, one or both of the longer edges of elliptical wheel704may have an indentation such that the indentation provides a recess or a notch for stopper714to rest and stop rotation of wheel704. Thus, stopper714enables anchoring of wire702with wheel704. At its other end, wire702is connected to a proximal end of a bending section within insertion portion708. In embodiments, wire702is placed inside a coil706. Coil706enables movement of wire702, and is fixed to the internal surface of insertion portion708.

In embodiments, wheel704is connected to a shaft712, which in turn is connected to a lever710. Thus, lever710operates wheel704. In embodiments, lever710is manually operated, and the extent of its rotation influences the degree of stiffness of insertion portion708. In operation, rotation of lever710rotates wheel704, which influences wire702. Consequently, wire702either tightens or relaxes, based on the direction of rotation of lever710.

FIG. 7billustrates another perspective view of the endoscope handle with the elliptical wheel arrangement ofFIG. 7a. In the arrangement, wheel704is located at a proximal end of the endoscope's handle, and wire702extends towards a distal end into insertion portion708.

FIG. 7cillustrates an enlarged two-dimensional view of assembly700, in accordance with some embodiments. In embodiments, wheel704has an asymmetric shape, similar to an ellipse. In this figure, one side716is visible, and the second side cannot be seen. Central edge of wheel704is also hidden behind side716, between the two sides. Wire702is seen connected to stopper714and passing over the central edge of wheel704. The concentric center of elliptical wheel704allows its radius to increase as wheel704rotates. Increased radius results in tightening of wire702. Shaft712, connected to lever710, rotates with the movement of lever710. Wheel704is placed on shaft712and rotates with it. In embodiments, wire stopper714is adapted to fix position of wire702relative to wheel704. In embodiments, one of the longer edges of elliptical wheel704may have an indentation such that the indentation provides a recess or a notch for stopper714to rest and stop rotation of wheel704. Thus, stopper714enables anchoring of wire702with wheel704. At its other end, wire702is connected to a proximal end of a bending section within insertion portion708. Once the wheel stops rotating, wire702may not move further around outer edge of centre portion of wheel704, thus fixing location of wire702relative to wheel704.

FIGS. 8aand 8billustrate cross-sectional views800of another embodiment for varying the stiffness of an insertion portion802of an endoscope involving a screw mechanism located within the handle of an endoscope. Simultaneously referring toFIGS. 8aand 8b, the mechanism includes a screw804placed within a housing806located in the handle of the endoscope. In embodiments, housing806further includes an internal housing (further illustrated inFIG. 9) to house a wire stopper808. In embodiments, internal housing moves in accordance with a tightening/releasing movement of screw804, in a direction that is at least one of a distal direction and a proximal direction along the longitudinal axis of the endoscope assembly. In embodiments, a proximal end of a wire810is connected to stopper808. Distal end of wire810is connected to a proximal side of a bending portion at distal end of insertion portion802. In embodiments, an opening818in the endoscope handle provides an optimal space and location suitable to place the screw mechanism in accordance with described embodiments. In some embodiments, a knob on the handle, such as knob405described with reference toFIG. 1, may be used to rotate the screw804. The knob is in communication with the screw such that a rotation of the knob causes a rotation of the screw. In some embodiments, the physical connection between the knob and the screw804may be geared such that a large rotation of the knob405would cause a smaller rotation of the screw or a small rotation of the knob would cause a larger rotation of the screw804.

Referring toFIG. 9in combination withFIGS. 8aand 8b, a three-dimensional view of the screw mechanism ofFIGS. 8aand 8bis illustrated. In addition to components described in context ofFIGS. 8aand 8b,FIG. 9illustrates an internal housing906, placed within housing806. Internal housing906moves with tightening/releasing of screw804. In embodiments, as screw804is tightened, internal housing906moves in a direction of its proximal end908, towards a proximal end904of housing806. In operation, screw804may be rotated around a longitudinal axis of the endoscope's handle. Rotating screw804may cause internal housing906to move along the longitudinal axis. In embodiments, rotation of screw in a clock-wise direction814may move internal housing906in a proximal direction816, towards a proximal end of the endoscope's handle. In embodiments, distal end of wire810is connected to a proximal end of a bending section within the endoscope. In embodiments, wire810is placed within a coil812, which enables movement of wire810. Coil812is fixed to the internal surface of insertion portion802.

Screw804is connected to proximal end908. In embodiments, screw804is screwed inside internal housing906through its proximal end908. Rotation of screw804moves internal housing906closer to proximal end904of housing806, in proximal direction816. Consequently, wire810is pulled resulting in stiffening of the insertion portion. When screw804is released, internal housing906moves towards a distal end902of housing806, resulting in a relaxed insertion portion. Therefore, movement of screw804influences tightening or loosening of wire810.

In embodiments, an opening818in the endoscope handle provides an optimal space and location suitable to place the screw mechanism in accordance with described embodiments.FIG. 10illustrates housing806and the screw mechanism placed inside opening818in a handle1002of the endoscope. In embodiments, internal design of scope handle1002allows secure placement of the screw mechanism.FIG. 10illustrates a view of handle1002when it is open. Once handle1002is closed and locked, the screw mechanism is invisible, secure, and intact. The mechanism may be operated, likely to tighten screw804, during a maintenance activity when handle1002is unlocked and opened to reveal the screw mechanism.

Referring toFIGS. 11aand 11b, an additional embodiment is described, which influences stiffness of an insertion portion of an endoscope.FIG. 11aillustrates a cross-sectional view of a handle1100. A service channel opening leads to a working channel1104inside handle1100. Working channel1104extends towards tip section of the endoscope, stretching over entire length of an insertion portion1106. In embodiments, an enforcement layer1108is placed over an outer periphery of working channel1104. In embodiments, layer1108may be manufactured from a metal that is from the family of stainless steel metals, or any other material that may stiffen working channel1104such that utility of working channel1104remains unaffected. Physicians are able to insert surgical tools and/or equipment to perform procedures through working channel1104that is covered by layer1108. Working channel1104stretches over entire length of insertion portion1106, therefore layer1108may influence stiffness characteristic of insertion portion1106, for example by providing permanent stiffness to insertion portion1106.

FIG. 11billustrates a cross-sectional view of working channel1104inside the endoscope handle. The figure also clearly illustrates enforcement layer1108on the outer periphery of working channel1104.

Although the present specification has been described with particular focus on an actuator that can controls a super-elastic element in order to vary stiffness of an insertion portion in an endoscope assembly, the present specification is also designed to vary stiffness through means of fluid and gas provided within the insertion portion. Therefore, various embodiments of the present specification describe elements (solid, liquid, and gas) that are controlled through different mechanisms to vary stiffness of an insertion portion in an endoscope.

Referring now toFIG. 12, a longitudinal cross-sectional view of a portion of an elongated shaft in an endoscope is shown, in accordance with some embodiments. For purposes of describing the specification, elongated is termed as the ‘insertion portion’, since it is the part of the endoscope assembly that is inserted inside a body cavity.

An insertion portion1222terminates at a tip section1224, which is at the distal end (that is, the end that is farthest from the endoscope handle) of insertion portion1222. In embodiments, at a proximal end, a handle connected to insertion portion1222assists/help maneuvers the insertion portion within the body cavity. The arrangement of these components is described above with reference toFIG. 1. In some embodiments, a flexible tube1226extends from the proximal end of insertion portion1222along its entire length. In embodiments, flexible tube1226is a separate tube outside a working channel and inside insertion portion1222. In embodiments, length of flexible tube1226may vary with the length of insertion portion1222. Diameter of flexible tube1226may also vary to adapt to the endoscope device where is it embedded. In embodiments, flexible tube1226may have an amorphous shape that adapts to space available within insertion portion1222. In embodiments, flexible tube1226is manufactured with a polymer that is used for conductivity of fluid under pressure. Examples of such polymer may include, but are not limited to, Polyurethane, Polyamide, Polyethylene, Polypropylene, Nylon, Silicon, and TPE.

The illustrated embodiment shows flexible tube1226terminating at tip section1224. In alternative embodiments, flexible tube1226terminates some distance prior to tip section1224, and within the bending section of insertion portion1222. In other embodiments, flexible tube1226terminates just before a first vertebra of the bending section, or at a proximal end of the bending section. In embodiments, flexible tube1226is configured to enclose a fluid, such as but not limited to water. In embodiments where water inflates flexible tube1226, the water may be sourced from the same supply that feeds the injector channel. Flexible tube1226may be sealed at its distal end, referred to as a sealed end1234, such that it carries a volume of water enclosed within flexible tube1226. An increase in this volume results directly in an increase of pressure of the water inside the flexible tube1226, which, in turn, results in an increase in stiffness (or decrease in flexibility) of flexible tube1226. Conversely, a decrease in this volume results directly in a decrease of pressure of the water inside the flexible tube1226, which, in turn, results in a decrease in stiffness (or increase in flexibility) of flexible tube1226. This arrangement also affects the overall flexibility of insertion portion1222, thus enabling control over its maneuverability inside a body cavity.

In embodiments, a pressure pump1228is connected to flexible tube1226at the proximal end of insertion portion1222. In alternative embodiments, pressure pump1228is connected through the handle to flexible tube1226. Pressure pump1228may control the pressure of water inside flexible tube1226. Pressure control may be enabled through a button, a switch, or a knob located on the handle or on a main control unit of the endoscope assembly or by a foot pedal. The control may adjust the pressure by varying an operating voltage or by using a pressure regulator. In embodiments, water is input at an inlet1230of pump1228. Water of variable pressure may be output through an outlet1232, which feeds into flexible tube1226. In embodiments, a user/physician interfaces with a scale that allows selection of a stiffness percentage, such as in the range of 0% to 100%. 0% may represent an insertion portion stiffness without any pressure, inside flexible tube1226. And 100% may represent insertion portion1222with the maximum pressure that may be applied inside flexible tube1226. A percentage value within this range may vary based on user requirements.

In alternative embodiments, other fluids may be used in place of water, within flexible tube1226. Variable viscosity of a fluid may contribute to variation in stiffness of flexible tube1226containing the fluid. Therefore, any fluid that may change its viscosity properties may be used within flexible tube1226. In embodiments, the fluid within flexible tube1226may undergo a viscosity change due to a change in at least one of temperature, electric charge, magnetic field, exposure to light, or any other factor influencing viscosity. Examples of such fluids may include, but are not limited to, electrorheological fluids that change viscosity based on an applied electric field, non-Newtonian fluids that change viscosity based on shear rate or shear rate history, magnetorheological fluids that change viscosity based on a magnetic field, photo-rheological fluids that change viscosity based on exposure to light, and the like.

In embodiments, electrorheological fluids (ERFs) are material composed of dielectric properties suspended in an insulating oil. Flow characteristics of ERFs may depend on properties of the dispersed material and the oil. Examples of ERFs include dispersions consisting of oil (mineral or silicon oil) and solid polymer particles, Hydroxyl-terminated silicon oil, RheOil®, and the like. In embodiments, magnetorheological fluids (MRFs) are liquids that display adjustable flow properties through introduction of magnetic fields. As a result, their characteristics can be changed from free flowing to solid and back again in a few milliseconds. Examples of MRF include fluid made using Carbonyl Iron powder, hydrocarbon-based MRFs, and the like.

In embodiments, pump1228is a lightweight pump suitable for liquids that provides a high-pressure capability for a small device. Pump1228may be a small-sized pump that delivers a consistent flow throughout a wide range of varying pressures. In embodiments, an electronic driver circuit may be used to operate the motor of pump1228.

FIG. 12also illustrates a horizontal cross sectional view of insertion portion1222above its longitudinal cross-sectional view. This view shows an exemplary position of flexible tube1226within insertion portion1222. Flexible tube1226is seen positioned at the radial center of insertion portion1222. Thus, flexible tube1226enables variation in flexibility of insertion portion1222from within and from its center. In another embodiment, flexible tube1226may be positioned in an empty space within and along insertion portion1222. In embodiments, such empty spaces may include but are not limited to spaces between electronic wires, working channels, and air/water channel(s).

In an alternative embodiment, flexible tube1226is coiled around an outer circumferential surface of a treatment tool insertion channel, such as a working channel, embedded within insertion portion1222. In this case, flexible tube1226coils around entire length of the working channel extending from the proximal end of insertion portion1222. In another embodiment, flexible tube1226coils around the working channel and terminates some distance prior to the bending section of insertion portion1222.

In yet another embodiment, flexible tube1226is replaced with a flexible lining that extends from a proximal end of insertion portion1222along length of insertion portion1222. The flexible lining may form a tubular wall concentric to the inner wall of insertion portion1222such that a gap exists between the two walls. In embodiments, at least one flexible lining stretches along the inner wall of insertion portion1222. In alternative embodiments, multiple flexible linings may be utilized. The flexible lining forms a parallel wall inside insertion portion1222such that a gap exists between the parallel wall and the inner wall of insertion portion1222. A pressure pump may be connected to the gap at the proximal end of insertion portion1222that controls pressure of a fluid that fills the gap.

FIGS. 13a, 13b, 13c, and 13dillustrate various embodiments of methods that are utilized to seal the flexible lining. In embodiments, the flexible lining may be sealed at the distal end of insertion portion1222.FIG. 13aillustrates a method of sealing by soldering a flexible lining1302, with the wall of an insertion portion1304at its distal ends1306. In embodiments, flexible lining1302may be punched at its distal ends with insertion portion1304.

FIG. 13billustrates another embodiment where a plug1308is utilized in addition to sealing by soldering flexible lining1302with the wall of insertion portion1304at its distal ends1306. Plug1308may be placed between inner walls of flexible lining1302proximal to ends1306to provide additional support to sealed ends1306.

FIG. 13cillustrates another embodiment where an Ultra Violet (UV) cure adhesive1310is used to seal open ends of flexible lining1302, in addition to plug1308.

FIG. 13dillustrates yet another embodiment where only UV cure adhesive1310is used to seal open ends of flexible lining1302.

FIG. 14illustrates a cross-sectional view of another embodiment of an insertion portion1402. In this embodiment, two or more flexible tubes1404are inserted within insertion portion1402. Sealed ends1406towards the distal ends of each of tubes1404may seal the tubes, such that it carries a volume of water enclosed within tubes1404.

An increase in this volume results directly in an increase of pressure of the water inside the flexible tubes1404, which, in turn, results in an increase in stiffness (or decrease in flexibility) of flexible tubes1404. Conversely, a decrease in this volume results directly in a decrease of pressure of the water inside the flexible tubes1404, which, in turn, results in a decrease in stiffness (or increase in flexibility) of flexible tubes1404. This arrangement also affects the overall flexibility of insertion portion1402, thus enabling control over its maneuverability inside a body cavity.

FIG. 15illustrates a cross-sectional view of yet another embodiment of an insertion portion1502. In this embodiment, a flexible tube1504is inserted inside insertion portion1502. Tube1504stretches along one side of an inner wall of insertion portion1502, and may continually stretch along another side of the inner wall of insertion portion1502. Tube1504may bend near the distal end of insertion portion1502to direct its water contents along other sides of its inner wall. In embodiments, flexible tube1504may be placed within insertion portion1502during its extrusion. In alternative embodiments, a guide is used to insert and place flexible tube1504inside insertion portion1502. Once tube1504is placed, the guide may be withdrawn from insertion portion1502.

FIG. 15also illustrates a pressure-regulating valve1506that may be used to stop or allow the water within tube1504from flowing back to a pressure pump1508through an inlet1510. In embodiments, once pressure-regulating valve1506is closed, water stops flowing out of tube1504, such that a volume of water is enclosed within tube1504. An increase or decrease in this volume results directly in an increase or decrease of pressure of the water inside tube1504. An increase in this volume results directly in an increase of pressure of the water inside the flexible tube1504, which, in turn, results in an increase in stiffness (or decrease in flexibility) of flexible tube1504. Conversely, a decrease in this volume results directly in a decrease of pressure of the water inside the flexible tube1504, which, in turn, results in a decrease in stiffness (or increase in flexibility) of flexible tube1504. This arrangement also affects the overall flexibility of insertion portion1502, thus enabling control over its maneuverability inside a body cavity.

FIGS. 16a, 16b, 16c, and 16dshow longitudinal cross-sectional views of a portion of an elongated shaft in an endoscope in accordance with another embodiment. Referring toFIGS. 16ato 16d, an insertion portion1602terminates at a tip section1610(shown inFIG. 16a), which is at the distal end of insertion portion1602. In embodiments, at a proximal end, a handle (not shown) connected to insertion portion1602assists in maneuvering it within the body cavity. The arrangement of these components is described above with reference toFIG. 1.

Referring toFIG. 16a, in embodiments, a flexible tube1604aextends from the proximal end of insertion portion1602along its length. The illustrated embodiment shows flexible tube1604aterminating near tip section1610. In alternative embodiments, flexible tube1604aterminates within the bending section of insertion portion1602. In another embodiment, flexible tube1604aterminates some distance prior to the bending section of insertion portion1602. In embodiments, flexible tube1604ais configured to carry gas, such as but not limited to air, or fluid. In embodiments where gas/fluid inflates flexible tube1604a, the gas/fluid may be sourced from the same supply that feeds the injector channel. Flexible tube1604amay open into a sealed gas chamber1612near tip section1610, such that the gas carried by tube1604ais filled inside chamber1612.

An increase or decrease in this volume of the gas within tube1604aresults directly in an increase or decrease of pressure of the gas within chamber1612. An increase in this volume results directly in an increase of pressure of the gas within chamber1612, which, in turn, results in an increase in stiffness (or decrease in flexibility) of insertion portion1602that houses chamber1612. Conversely, a decrease in this volume results directly in a decrease of the pressure of the gas within chamber1612, which, in turn, results in a decrease in stiffness (or increase in flexibility) of insertion portion1602that houses chamber1612.

Referring toFIG. 16b, an additional flexible tube1604bis shown. Flexible tube1604bmay be similar in its characteristics and operation to flexible tube1604a, and may open into a different chamber1614(similar to chamber1612). In embodiments, chamber1614may be located adjacent to chamber1612along the longitudinal axis of insertion portion1602. In another embodiment, chamber1614is located at a predefined distance from chamber1612along the longitudinal axis of insertion portion1602. Chambers1612and1614may be placed concentrically, such that chamber1612is inside chamber1614, and both are aligned inside and along the inner circumferential surface of insertion portion1602.

Referring toFIG. 16c, another flexible tube1604cis shown. Flexible tube1604cmay be similar in its characteristics and operation to flexible tubes1604aand1604b, and may open into a third chamber1616(similar to chambers1612and1614). In embodiments, chamber1616may be located adjacent to chamber1614along the longitudinal axis of insertion portion1602. In an embodiment, chamber1616may be located at a predefined distance from chamber1614along the longitudinal axis of insertion portion1602. Chambers1612,1614, and1616may be placed concentrically, such that chamber1612is inside chamber1614, which is inside chamber1616, and both all are aligned inside and along the inner circumferential surface of insertion portion1602.

In embodiments, insertion portion1602may include multiple chambers, and the number of chambers may vary. Length of chambers may also vary. In an embodiment, length of the chambers may vary from 1 to 30 cm. In other embodiments, the lengths may exceed 30 cm.

Pressure of gas/fluid may be varied separately in all of the chambers described in the above embodiments to variably control stiffness of insertion portion1602.

In embodiments, a pressure pump1608is connected to flexible tubes1604a,1604b, and1604c, at the proximal end of insertion portion1602. In alternative embodiments, pressure pump1608is connected through the handle. Pressure pump1608may control pressure of gas inside each flexible tube1604a,1604b, and1604c. A switch1606or any other external control (such as a button or a knob) may enable an operator to configure pressures within each tube and thus each chamber, to manage stiffness of insertion portion1602. Switch1606may be located on the handle or on a main control unit of the endoscope assembly. The control may adjust the pressure by varying an operating voltage or through a pressure regulator.

Various embodiments of the specification described herein may thus allow flexibility of an insertion portion of an endoscope to vary, thereby increasing ease of navigation through different parts and contours inside a body cavity while solving problems related to looping. The gas and fluid pressure controls provide an additional layer of control over the flexibility of the insertion portion of most available endoscopes.

Alternative embodiments may also be considered that enable control over the flexibility of the insertion portion. These additional alternatives may be in the form of various methods of manufacturing the insertion tube of the insertion portion. Such embodiments enable flexibility of the insertion tube to be controlled on the basis of the manufactured characteristics of the tube. Some embodiments of methods of manufacturing are discussed here.

Immersion Method

The immersion method of manufacturing the insertion tube may enable control over rigidity of different areas of the tube. Rigidity of the tube may be controlled by use of different viscosity liquids that construct the base material of a jacket of the tube, which is also known as a sheath. In embodiments, the jacket may be Thermoplastic Polyurethane. Additionally, a portion of the sheath may be of the braided hose type. In embodiments, the hose braid may be manufactured using stainless steel, or a synthetic material, or Kevlar, or any other material known in the art. In embodiments, the type of hose braid used (wire diameter, number of wires per bobbin, number of carriers) also affects the rigidity of the tube. Moreover, flat coils may be used as framework for insertion tubes to provide control over the rigidity of the tube. In embodiments, flat coils may be manufactured using stainless steel, or copper, or any other material known to manufacture flat coils. An advantage of the immersion method is that the insertion tubes manufactured by this method do not require an extra coating.

Extrusion Method

This method offers advantages when the control over stiffness of the insertion tube is maintained with hose braids and flat spirals. One of the advantages include an improved quality of connection of the insertion tube with its mesh, which is used for the jacket. The improved quality of connection ensure that the sheath remains attached to the tube braid, and thus a widespread form of beads bend in the insertion tube in a tight radius. With a surface treatment of the tubular braid and/or use by the extrusion, a uniform thickness of the casing is achieved. This also results in improved uniformity of stiffness in the rigidity zones. Another advantage is that insertion tubes have a constant stiffness among different manufacturing batches. As a result, the reject rate in production by this method is much lower. Additionally, the tubes manufactured by this method may have a relatively smoother surface. The insertion tubes manufactured by this method also do not require an extra coating.

Shrink Tube Method

In this method, flat coils are prepared with the hose braid, and coated with a heat shrink tube, followed by baking in an oven until maximum shrinkage is reached. Variable stiffness may be achieved with this method by differing the quality of the flat coils and of the hose braid.

Various embodiments of the specification described herein may thus allow flexibility of an insertion portion of an endoscope to vary, thereby increasing ease of navigation through different parts and contours inside a body cavity while solving problems related to looping.

The above examples are merely illustrative of the many applications of the system of present specification. Although only a few embodiments of the present specification have been described herein, it should be understood that the present specification might be embodied in many other specific forms without departing from the spirit or scope of the specification. Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive, and the specification may be modified within the scope of the appended claims.