All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.
The invention relates generally to guide tubes that can be inserted into a body cavity. More particularly, the invention relates to guide tubes that can be used in endoscopic procedures.
In medical procedures it is often necessary to place a medical device within a body lumen. Examples here include colonoscopy, endoscopy, arthroscopic procedures, catheterization and the like. In such procedures it is desirable to limit inadvertent damage to the body lumen that can be caused by the medical device. Similarly, it can be difficult to place with device within the body lumen due to the many branches and folds that often exist in such body lumens. As a consequence, it is often desirable to first place a guide tube or lumen within the body lumen itself. Such a tube can limit body damage and speed up the medical procedure, i.e. the physician's efforts can be focused on applying the medical device rather than placing it. For example, before performing a colonoscopy it is first necessary to insert and place a relatively stiff colonoscope into the colon. Safe placement requires that the physician must carefully insert and advance the colonoscope over 1 meter into the colon without causing mechanical damage to the colon itself. As a consequence, the individual inserting the colonoscope often requires years of training and practice. While experienced physicians have low injury rates, the training required and the time added to the colonoscopy procedure result in higher costs and added procedure time.
One means of circumventing these requirements is to first place a guide tube within the body lumen. If such a guide tube were cost-effective and easily deployed, it could yield a safer procedure in which a guide tube is first deployed within the colon, after which the colonoscope can be rapidly and safely placed. Ideally, deployment of such a guide tube could be done with ease and provide little risk such that it could either be deployed by a less experienced operator or it could be more rapidly deployed by an experienced operator. Such a device would reduce the time that the skilled physician must spend with the patient and lower the overall cost of the procedure. Unfortunately, no guide tube schemes disclosed to date have met these criteria and, as a consequence, they have not been widely adopted.
In most schemes disclosed in the prior art, the guide tube is deployed within the body lumen by eversion with a means of pressurization provided at the proximal end. A major limitation of the prior art is associated with the high resistive forces that occur as the guide tube is deployed. Such resistive forces can arise during guide tube deployment as a result of twisting of the guide tube or as a result of the general tendency for the guide tube to become tangled or disordered at its proximal end. Resistive forces can also arise when air pockets are trapped within the center region of the guide tube so that the inverted section of the guide tube is not fully compressed. This increases the cross sectional area of the guide tube and provides a larger inner surface area, thereby increasing the overall resistive drag force associated with this surface. Furthermore, the prior art either uses no distal valve to limit outward fluid flow or uses valve schemes that are overly cumbersome or ineffective. As a result of these and similar restrictions, the systems used in the prior art require deployment pressures and inflation fluid volumes that are higher than desirable and that pose a risk of bodily injury. Furthermore, most systems in the prior art are overly cumbersome and impractical to operate. As a consequence, systems disclosed in the prior art are not in widespread use today.
The present invention relates generally to guide tubes that can be inserted into a body cavity. More particularly, the invention relates to everting guide tubes that can be used in endoscopic procedures.
In some embodiments, an endoscopic guide tube device to facilitate the insertion of an endoscope or similar device into a body lumen is provided. The device can include a pressurization chamber comprising a nozzle and an inner surface of a wall that defines an interior, wherein the nozzle has an opening; an everting tube having a proximal end and a distal end, wherein the everting tube is mounted within the pressurization chamber with the proximal end of the everting tube attached to the pressurization chamber; a port on the pressurization chamber configured to allow a positive pressure to be delivered to the interior of the pressurization chamber, wherein the positive pressure is configured to deploy the everting tube outwards through the nozzle; and a valve located at or proximate the distal end of the everting tube, wherein the valve is configured to open when the everting tube is fully deployed.
In some embodiments, an endoscopic guide tube device to facilitate the insertion of an endoscope or similar device into a body lumen is provided. The device can include a pressurization chamber containing an everting tube mounted within said pressurization chamber with a proximal end of said everting tube mounted to be attached to said pressurization chamber; a port on said pressurization chamber whereby a positive pressure can be delivered to the interior of said pressurization chamber to cause said everting tube to deploy outward through said nozzle; and a self-sealing valve means located at or near the distal end of said everting tube which opens when guide tube is fully everted.
In some embodiments, the pressurization chamber of the endoscopic guide tube device has a pressure relief valve configured to prevent excessive positive pressures from occurring within the everting tube. In some embodiments, the pressure relief valve is configured to prevent excessive positive pressures from occurring within the everting tube during or after deployment. In some embodiments, the pressurization chamber is in communication with a pressure sensor configured to measure pressure within the pressurization chamber.
In some embodiments, the everting tube is wound on a deployment spool located within the pressurization chamber. In some embodiments, the deployment spool comprises a central axle and an outer diameter surface on which the everting tube is wound. In some embodiments, the deployment spool has a diameter equal or greater than 0.2 inches. In some embodiments, the central axle of the deployment spool is positioned such that a portion of the outer diameter surface of the deployment spool is nominally aligned with the opening of the nozzle to reduce or minimize frictional resistance between the everting tube and the nozzle during deployment of the everting tube.
In some embodiments, the pressurization chamber has restraints or indentations on opposite sides of the inner surface of the pressurization chamber which are configured to restrain the central axle of the deployment spool, wherein the restraints or indentations do not extend through the wall of the pressurization chamber such that the deployment spool axle is fully contained within the pressurization chamber and does not extend through the wall of the pressure chamber. In some embodiments, either one end or both ends of the central axle of the deployment spool extends through the inner surface of the pressurization chamber, wherein a wheel is attached to one end of the axle or wheels are attached on both ends of the axle, wherein the one or more wheels are located outside the pressurization chamber and are configured to apply an external twisting force to the deployment spool. In some embodiments, the device further includes an axle extended across the interior of the pressurization chamber, wherein the deployment spool comprises a cylindrical tube disposed over the axle such that the deployment spool can rotate independently of the axle. In some embodiments, the device further includes an axle extended between the two sides of the pressurization chamber and the spool is formed by a cylindrical tube that passes over the axle but where the spool is not rigidly attached to the axle and may rotate independently of the axle. In some embodiments, the deployment spool comprises a hollow shaft with no axle that is located inside the pressurization chamber and is constrained within the pressurization chamber by restraints located on opposite walls of the pressurization chamber.
In some embodiments, the everting tube is attached to the nozzle and the nozzle is detachable from the pressurization chamber to allow the nozzle and attached everting tube to be physically separated from the pressurization chamber. In some embodiments, the nozzle incorporates a seal such that when the endoscope is inserted through the nozzle the seal resists fluid escape from around the endoscope where the endoscope enters the nozzle. In some embodiments, the nozzle incorporates a seal such that when the endoscope is inserted through the nozzle the seal resists fluid escape from the space between the inside surface of the nozzle and the outside surface of the endoscope where it enters the nozzle. In some embodiments, a second port is located on the nozzle to allow fluid communication to the interior of the everted tube, wherein the second port is configured to allow application of positive pressure to the interior of the everted tube from an external pressure source. In some embodiments, the nozzle has a distal end that is comprised of a non-rigid elastomeric material. In some embodiments, the nozzle has a proximal end, a distal end and a central region between the proximal end and the distal end, wherein the outside diameter of the central region of the nozzle is smaller than both the outside diameter at the proximal end and the outside diameter at the distal end of the nozzle. In some embodiments, the nozzle is formed from two or more mated pieces that can be separated to allow removal of the nozzle from the endoscope without having to remove the endoscope from within the nozzle.
In some embodiments, the everting tube has a seal at its proximal end that mates with the nozzle, wherein the seal is configured to allow the everting tube to be separated from the nozzle such that the endoscope can then be inserted into the proximal end of the everting tube through the seal.
In some embodiments, prior to deployment, the everting tube is folded within the pressurization chamber in an accordion-like manner into a plurality of folds such that the orientation of the folds within the pressurization chamber is orthogonal to the orientation of the central axis of the everting tube after deployment. In some embodiments, prior to deployment, the everting tube is wrapped within the pressurization chamber in a looped manner to form loops with an alternating winding orientation such that when the everting tube is deployed the twisting of the everting tube along its axis is reduced. In some embodiments, the everting tube is wrapped within said pressurization chamber in a looped manner such that the everting tube is twisted about +180 degrees around its axis and held in place and then twisted about −180 degrees about its axis and then held in place such that when said everting tube is deployed the net result will be little or no residual twisting of said everting tube along its axis. In some embodiments, the loops form a stacked arrangement within the pressurization chamber with the central axis of the stacked loops being generally parallel to the alignment of the everting tube when fully deployed. In some embodiments, the loops formed from the twisted everting tubes are stacked in an alternating manner such that the final arrangement forms a figure eight pattern with two sets of stacked loops, each of whose central axes are generally aligned parallel with the axis of the everting tube when fully deployed.
In some embodiments, the everting tube is formed from extruded low durometer polyurethane. In some embodiments, the wall thickness of the everting tube is 0.010 inches or less. In some embodiments, the everting tube is rolled or folded along its axial length prior to wrapping or folding it within the pressurization chamber. In some embodiments, the everting tube comprises a single material formed in a manner such that the everting tube has a section having a first diameter followed by a section having a second diameter which is repeated along the length of the everting tube to form an undulating pattern or a ribbed pattern along at least one half the length of the everting tube. In some embodiments, the surface of the everting tube is modified to reduce either its coefficient of friction or its adhesion properties, wherein the modification is selected from the group consisting of plasma energy treatment, application of polyvinylypyrrolidone, application of hyaluronic acid, application of parylene, application of friction reducing surface treatments, application of a biocompatible lubricating agent, application of glycerin, application of propylene glycol, application of a hydrophobic silicone based lubricant, and application of a water based lubricant.
In some embodiments, the distal end of the everting tube is temporarily sealed prior to deployment and wherein the distal end of the everting tube is configured to be opened by applying a force to the temporary seal at the distal end of the tube that is greater than the force used to cause the everting tube to deploy from the pressurization chamber. In some embodiments, the distal end of the everting tube is closed and wherein the distal end of the everting tube is configured to be opened by cutting or puncturing.
In some embodiments, the valve is formed from or attached to the distal end of the everting tube that has been modified such that, prior to full eversion, the distal end of the everting tube comprises two flat sections that are connected along two edges and have two common surface faces that are generally in direct contact with each other such that there is no significant gap between the two flat sections including at the edges where the two flat sections are connected such that a fluid barrier exists that prevents fluid from entering into the distal end of the everting tube. In some embodiments, the valve is integral to the distal end of the everting tube. In some embodiments, the valve comprises a distal portion of the everting tube that is temporarily sealed by an application of a viscous gel or grease on the interior surface of the everting tube. In some embodiments, the valve comprises an elastomeric material connected to the distal end of the everting tube, wherein in an unpressurized state the elastomeric material is in a constricted state that seals the distal end of the everting tube. In some embodiments, the valve is configured to open at an applied pressure of 3 to 5 psi.
In some embodiments, a method of inserting an endoscope into a body lumen is provided. The method can include providing an everting tube having a proximal end and a sealed distal end; partially deploying the everting tube within the body lumen; advancing the endoscope into the partially deployed everting tube while maintaining a nominal seal between the endoscope and the proximal end of the partially deployed everting tube; advancing the endoscope within the everting tube until the endoscope reaches the distal end of the partially deployed tube; applying pressure to the sealed distal end using the endoscope; and opening the sealed distal end to fully deploy the everting tube.
In some embodiments, the method further includes inflating the everting tube via pressurization delivered from the endoscope. In some embodiments, the method further includes inflating the everting tube through a port in communication with the everting tube using an external pressure source.
In some embodiments, an endoscopic guide tube device to facilitate the insertion of an endoscope or similar device into a body lumen is provided. The device can include a pressurization chamber comprising a nozzle and an inner surface that defines an interior, wherein the nozzle has an opening; an everting tube having a proximal end and a distal end, wherein the everting tube is mounted within the pressurization chamber with the proximal end of the everting tube attached to the pressurization chamber; a port on the pressurization chamber configured to allow a positive pressure to be delivered to the interior of the pressurization chamber, wherein the positive pressure is configured to deploy the everting tube outwards through the nozzle; and a tether having a proximal end and a distal end, wherein the distal end of tether is attached to one or more locations on a distal portion of the everting tube, wherein the proximal end of the tether is separately connected or held to an external body such that, prior to full deployment of the everting tube, the length of the distance between the two ends of the tether is less than the fully deployed length of the everting tube such that the tether prevents full deployment of the everting tube until the tether is released from the external body.
In some embodiments, the device can further include a distal seal located at the distal end of the everting tube. In some embodiments, the distal seal comprises two sheets connected at the edges and lying adjacent to each other with no space existing between the two sheets. In some embodiments, the distal seal comprises a viscous or adhesive material disposed within the distal end of the everting tube. In some embodiments, the distal seal comprises a pressure bond at the distal end of the everting tube. In some embodiments, the distal seal comprises an elastic or non-elastic material disposed around the distal end of the everting tube. In some embodiments, the distal seal comprises a portion of the tether wrapped around the distal end of the everting tube.
In some embodiments, the device can further include a deployment spool located within the pressurization chamber, wherein the proximal end of the tether passes though the nozzle of the pressurization chamber and is releasably attached to the deployment spool.
In some embodiments, the external body is dimensioned larger than either the inner diameter of the nozzle or the everting tube such that the external body is too large to pass through the nozzle.
In some embodiments, the valve is self-sealing.
In some embodiments, the device further includes a second port configured to allow negative pressure to be applied to the interior of the everted tube while a positive pressure is applied within the interior of the pressurization chamber to create two forces which both act to remove trapped air located within the everting tube before it is deployed.
In some embodiments, the device further includes a temporary seal placed near the proximal end of the everting tube prior to deployment and a second temporary seal placed at the distal end of the everting tube prior to deployment, wherein the temporary seal at the proximal end is physically accessible via the nozzle opening such that a negative pressure can be applied to the interior of the everting tube such that residual gas or fluid can be removed to reduce the cross sectional area of the everting tube.
In some embodiments, the device further includes a temporary seal located on the distal end of the everting tube and a second removable seal located over the nozzle opening to provide an airtight seal such that a negative pressure to remove air can be applied to an interior volume formed by the seals and the everting tube.
In some embodiments, the everting tube comprises a wall structure that includes a first flexible material and a second flexible material that has a higher modulus of elasticity than the first material used to form the everting tube wall, wherein the second material is wrapped around the first material in loops or a helical pattern.
In some embodiments, a semi-rigid tube device is provided. The device can include a tube having an outside diameter smaller than the everting tube and an inside diameter larger than the endoscope with openings at both ends and a flange at its base to prevent passage through the rectum. In some embodiments, the tube is flexible and has a slit that runs along its entire length where the tube material is a polymer that is sufficiently flexible such that when an endoscope is passed through the semi-rigid tube, the semi-rigid tube can be pulled sideways off the endoscope by allowing the endoscope to pass through the slit.
In some embodiments, a method of performing endoscopy in the colon is provided. The method can include deploying an everting guide tube within the colon then inserting the semi-rigid tube into the everting guide tube. The everting guide tube and/or the semi-rigid tube can be advanced past the sigmoid flexure of the colon to straighten the colon, after which an endoscope is advanced into the colon.
In some embodiments, the semi rigid tube device is employed and the method adds the additional step of retracting the semi-rigid tube after the endoscope has been inserted and removing the semi-rigid tube by pulling it sideways off the endoscope by passing the endoscope through the slit in the side of the semi-rigid tube.
In some embodiments, a method of manufacturing the device is provided. The method can include applying a negative pressure to the interior of the everting tube before it is wrapped or folded.
In some embodiments, the method further includes placing a temporary seal near the proximal end of the everting tube and placing a second temporary seal at the distal end of the everting tube by either compression and wrapping of the everting tube or by placement of a temporary seal around the outside of the everting tube, after which a needle and syringe or similar device is inserted through either the temporary seal and a negative pressure is applied to the interior volume within the sealed everting tube in order to reduced the cross sectional area of the everting tube. In both cases the temporary seals open when pressure is applied to the pressurization chamber to cause deployment of the everting tube.
In some embodiments, the device is formed by heating and pressing a section of tube having an otherwise nominally circular cross section such that the material is heated to at or near its transition temperature such that its shape is permanently changed from a nominally circular cross section to a nominal cross section existing substantially of two flat sheets connected along their two edges.
In some embodiments, a method of manufacturing the device is provided. The method can include providing a thin flat material having a width nominally equal to 3.14*D/2, where D is the tube diameter, and inserting the thin flat material into the distal end of the everting tube prior to heating in order to prevent the two surfaces from bonding together.
In some embodiments, a method of manufacturing the device is provided. The valve can be formed by bonding two flat sheets to the distal end of a nominally circular tube and bonding those two sheets together along their edges so that the distal end of the tube terminates in a normally closed, flat valve. In some embodiments, the valve can be formed by applying a viscous gel or grease on the interior surfaces of a nominally circular everting tube near its distal end to temporarily seal the end of the tube until it is fully deployed by eversion delivery. In some embodiments, a viscous grease or gel substance is applied on the internal surfaces of the everting tube at its distal end within the formed valve region the evertable tube.
In some embodiments, a passive valve that is normally closed is provided. The valve can be located at the distal end of a nominally circular evertable tube wherein the valve includes a deformation of the nominally circular evertable tube within its distal region end region such that when the tube is in its relaxed, non-pressurized state, the deformed section forms a shape that substantially comprises two flat sheets connected at the edges and lying adjacent to each other with no space existing between the two surfaces, particularly at the edges of two surfaces.
The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
a is a longitudinal cross-section of an embodiment of a guide tube device.
b illustrates the insertion of an embodiment of a guide tube device into the opening of the body lumen and the initial deployment process.
c-1e are transverse cross-sections of embodiments of a guide tube device that illustrate the attachment of the spool to the deployment chamber.
a illustrates an embodiment of an endoscope inserted into the deployment nozzle that is attached to the proximal end of deployed guide tube.
b and 2c illustrate various embodiments of a deployment nozzle.
a and 3b illustrate an embodiment of the insertion of a deployment nozzle into the proximal end of a guide tube.
a-7c illustrates an embodiment of the eversion of a guide tube.
a-10c illustrate various embodiments of the thread orientation of a guide tube.
a-11c illustrate an embodiment of a guide tube having a valve that opens upon full eversion of the guide tube.
d illustrates a fully everted guide tube deployed within a body lumen.
a-12d illustrate various valve embodiments.
a-13c illustrate additional valve embodiments.
a-14c illustrate an embodiment a feature that restricts full deployment of the guide tube.
a-15c illustrate an embodiment of a guide tube with a tether.
For purposes of clarification, in this document the following definitions will apply:
The terms endoscope or colonoscope refer to a tubular device used for imaging the interior of a body lumen wherein the tubular device is inserted into the body lumen to the site of interest and an image is created for an operator using such means as a fiber optic imaging bundle or electronically such as can be achieved with a camera located on the distal end of the tubular device. The terms endoscopy and colonoscopy will refer to the procedure of using such a device.
When discussing devices such as an endoscope or guide tube, the proximal end will refer to the end to reside outside the body and closest to the operator while the distal end will refer to the end that is to be located furthest from the operator. Furthermore, the terms distal and proximal shall be applied to the guide tube, as if the guide tube is fully deployed (everted). When discussing a body lumen, the proximal end will refer to the end that is deepest within the body while the distal end will refer to that end closest to the outer orifice. In general, the most distal end of the endoscope will be located at the most proximal region of the body lumen.
The terms eversion, evert, everting or other derivations shall refer to the method of deploying a tube within a body cavity. For example, one method of eversion includes applying pressure to an inverted hollow tube to cause it to unfold at its distal end thereby reversing the inverted surface and extending the tube within a body cavity. The tube can be inverted for this purpose by folding the proximal end of the tube back over itself and securing it to the deployment system. Pressure is then applied to the interior cavity created within the tube so that the inverted portion moves through the proximal opening and extends outward, continually unfolding at its endpoint where it is folded back within itself. In one embodiment, the inverted portion of the tube within the interior cavity is flexible such that it is compressed by the applied deployment pressure to cause eversion so that the lumen of the inverted tube is caused to have a volume substantially less than it would in an open, uncompressed state. As the tube is being deployed the entire length of tube will be turned inside out by folding back onto itself. Other means can also be used to create the initial everted tube such as, for example, attaching to a distal end of the tube and pulling part of the tube back within itself so as to turn it partially inside-out. References here to eversion and its derivation are intended to cover these and similar means for partially inverting a tube and the deploying it through the application of internal pressure.
With this invention, we have overcome the limitations of the prior art by reducing the pressure and fluid volume that are required to deploy the guide tube. Furthermore, the invention is less complex than most past systems, thereby making it easier to use and more cost effective to manufacture. The reduction in required pressure is accomplished through incorporation of one or both improvements described within. The first being a low-resistance deployment device and the second, a distal valve incorporated in the guide tube. An example of a low-resistance deployment device is a spool mechanism that allows the guide tube to feed out smoothly and consistently during deployment with little or no resistance while limiting the tube's ability to twist or become entangled. The scheme of spooling the guide tube also limits the amount of air that can enter within the everted tube which is desirable since this air increases the cross section area within the center of the inverted tube and creates resistive drag. Other low-resistance deployment means disclosed here offer these same benefits. An example of a distal valve is also disclosed here. This valve is accomplished by flattening the distal end of the guide tube to limit outward flow of inflation fluid during deployment. This scheme is effective and easier to manufacture than the prior art. These and other features disclosed here provide a simple to use device that is operated with lower pressure and fluid volumes than were previously required, thereby making them safer to use within body cavities.
Shown in
In some embodiments, the entire length of the guide tube 7 is deployed by eversion. The deployment of the guide tube 7 can be achieved by the pressure provided by the deployment fluid in communication with the pressure chamber 1. The invention avoids several of the drawbacks of the prior art as exemplified above. This is achieved by employing one or more of the following elements: a single wall tube that is deployed within the body lumen by eversion, an integral valve at the distal end of the tube, a pressurization chamber external to the body to facilitate the eversion deployment process and a means within the pressurization chamber to reduce the friction and resistance that has hindered deployment in previous designs.
b illustrates the pressurization chamber after the deployment nozzle 2 has been inserted into the opening of the body lumen and initial pressure has been applied to initiate the deployment process. The guide tube 7 is depicted in an intermediate state of eversion with some length of the guide tube deployed. There is common communication between the pressurization chamber 1 and the annular cavity 35 of the guide tube. The differential pressure between the pressurization chamber 1 and the interior of the body lumen produces a net outward force at the distal surface 36 of the everting guide tube 7 that results in a forward force to cause eversion and deployment of the guide tube 7 within the body lumen.
The pressurization chamber 1 has several items contained within it and formed on its body. In some embodiments, the pressurization chamber 1 is formed such that its axis is aligned with the direction of the guide tube 7. As a specific example for purposes of explanation; the pressurization chamber is described here as having a cylindrical cross section but it can be other elongated shapes as well, such as one having a rectangular cross section. However, it is preferable that it have a generally elongated shape aligned with the axis of the guide tube 7 and being of a cross-sectional size that can be easily gripped in one hand. When the guide tube 7 is being deployed, the axis of the cylindrical tube of the pressurization chamber 1 is parallel to the axis of the body lumen into which the guide tube 7 is to be deployed. For example, in the case of colonoscopy, the patient lays on their side with their knees pulled toward the chest to allow easier access to the rectum. A right handed physician would then typically grip the pressurization chamber 1 in their left hand and insert the deployment nozzle 2 into the rectum and then apply pressure for deployment with the right hand using either a manual or automated pressurization device. As pressure is applied, force on the guide tube's 7 distal surface begins to cause the guide tube 7 to deploy within the body by means of eversion. The pressurization device could be one of any number of means known to those skilled in the art. Examples of manually pumped pressurization devices are single and double action pumps similar to those used routinely for inflation. Actions for such manual pumps are well known to those in the art and include a piston that is pulled in and out to apply pressure through a valve as well as trigger or lever action schemes similar to those used in caulking and grease guns. As an alternative to pressurization created by manual pumping, the pressurization chamber 1 can be pressurized via a connection to a higher pressure container via inflation port 4. In this case, inflation pressure can be applied either through a valve incorporated within inflation port 4 or either upstream or downstream of it. This approach provides for easier operation since pressure can be delivered via a finger or hand operated switch. In fact, when the action to control the pressurization valve is conveniently located, such as on the body of pressurization chamber 1, this scheme can allow the device to be held in place and pressurized with one hand while leaving the other hand free to perform other tasks.
As the guide tube 7 deploys further into the body lumen, the guide tube's 7 distal end will exit the deployment nozzle 2 and be pulled first into the lumen of the guide tube 7 at its proximal end. As the guide tube 7 is further deployed, the everting guide tube 7 will reach its maximum length at which point the valve at its distal end will open to complete the deployment process. When fully deployed, the guide tube 7 will include a single wall tube that lies within the body lumen with its proximal end outside the body lumen orifice. Full deployment can be detected by a drop in resistance to applied pressure or a drop in pressure in the pressurization chamber either as indicated by the pressure sensor 5 or by feel if using a hand pump. This occurs because the distal end of the guide tube 7 generally remains closed or sealed until eversion is completed, thereby maintaining the pressure in the pressurization chamber 1 as the guide tube 7 is everted. However, once the distal end is opened or unsealed at the completion of eversion, the pressure and pressurization fluid is allowed to dissipate into the body lumen, thereby decreasing the resistance to applied pressure and/or decreasing the pressure in the pressurization chamber 1.
In addition to the deployment nozzle 2, the pressurization chamber 1 has an inflation port 4 as well as an optional a pressure relief valve 3 and an optional port for attachment of a pressure gauge 5. In some embodiments, the pressure relief valve 3 is a simple mechanical device as is well known in the art, an example of which is a hole in the body of the pressurization chamber 1 that is covered by a flexible diaphragm. When the applied pressure within the pressurization chamber 1 exceeds safe limits, the diaphragm will flex to release pressure such that the unit prevents over-pressurization in the event that the operator inadvertently exceeds safe limits. Other valve means can be used to provide a fail-safe mechanism to prevent over-pressurization; the key point here is that one can be included on the body of the pressurization chamber 1 or similarly located so as to be in communication with the pressurization chamber 1.
In addition to the optional pressure relief valve 3, there is an inflation port 4 incorporated into the pressurization chamber 1 so that pressure can be increased within the pressurization chamber 1 so as to cause deployment of the guide tube 7 by eversion. In some embodiments, the fluid used in this pressurization process can be a gas such as air, a fluid means such as water or saline or similar gases or fluids that are well known in the art. In addition to these elements, there can also be a port for attachment of a pressure gauge 5 such that the operator can actively monitor the applied pressure if desired. The device may be made out of a variety of materials such as plastics or metal generally suitable for relatively low operating pressures. For example, in the colonoscopy application, since the colon can burst at pressures of 5 psi, the device can be built from materials suitable for that pressure range. For other applications the device can be built to provide the appropriate pressure, either higher or lower.
In addition to these elements on the body of the pressurization chamber 1, there are also internal elements as shown in
To minimize or reduce the potential for trauma to the body lumen, it is desirable to minimize or reduce the deployment pressure. We have found that the deployment spool 6 provides low resistance such that the guide tube 7 is deployed with such minimal, reduced or low pressure. One means that offers a particularly low resistance is when the outer diameter surface of the deployment spool 6 is generally aligned with the through hole 8 as shown in
In an alternative configuration shown in
Various means are provided to separate the deployed guide tube 7 from the pressure chamber 1 after the guide tube 7 is fully deployed. In one configuration the deployment nozzle 2 can be detached from the pressure chamber 1. A sealing member, such as an O-ring provides a seal between the mating surface of the pressure chamber 1 and the deployment nozzle 2. The union of the two parts can be made by mating threads, locking pins, external collar, clamp, etc. Separating the mating parts requires minimal activation such as a slight opposing twist.
a shows an endoscope 32 inserted into the deployment nozzle 2 that is attached to the proximal end of deployed guide tube 7. In one embodiment, the distal end of the deployed guide tube 7 is temporarily closed. Means for temporarily closing the distal end are discussed in association with
As shown in
In another embodiment of the deployment nozzle 2, illustrated in
In
An alternative to the figure eight coiling configuration is to stack individual loops of the guide tube 7 on top of the next as shown in the isometric view of
The guide tube 7 is typically formed from a long section of tubing as is known in the art. An example of a material for this guide tube 7 is low durometer polyurethane. In some embodiments, the guide tube 7 is formed by a seamless process such as blow molding of an extruded tube to achieve the desired tube diameter and wall thickness. Blow molding of the guide tube 7 as compared to a guide tube that is extruded to final dimensions, provides superior strength and better resistance to structural deformity when the resulting tube is pressurized during intended use. The diameter of the guide tube 7 is sized to be larger than the diameter of the endoscope 32 but not generally larger than the internal diameter of the body lumen. The guide tube 7 wall thickness is to be held as thin as possible to promote eversion yet thick enough to provide an adequate safety factor such that the guide tube 7 does not distend from internal pressure or become damaged from endoscope 32 passage. Minimum wall thickness of the guide tube 7 must be adequate to accommodate the hoop stress from pressurization. For example, in some embodiments, for a 14 mm diameter tube a wall thickness or 0.005″-0.010″ is functional. However, the wall thickness may be less or greater. The wall of the tube may be laminated, and include one or more materials or similar materials with varying specific properties, such as durometer, elasticity, Young's modulus, and other properties. In one embodiment, an example of optimal material property characteristics for a 14 mm diameter guide tube 7 would be a wall thickness equal to or less than 0.005″. Material that is very flexible as to promote eversion without adding resistance, does not distend when pressurized up to 10 psi and for those situations where the physician desires to view the body luminal surface as the endoscope is advanced, a transparent tube is preferred in some embodiments.
As shown in
In
In the embodiments shown in
When such a temporary vacuum seal is applied to the inner volume, the seal can be formed at the time when the device is manufactured and packaged or it can formed by the user just prior to guide tube 7 deployment. When the vacuum is created by the user, a syringe or similar device is attached to the distal end of the nozzle 2 and a vacuum is created by withdrawing the plunger of the syringe, after which pressure is applied to the pressurization chamber 1 to help prevent fluid from reentering the inverted guide tube. Alternatively, the order of these two operations can be reversed.
Note that such a vacuum and pressurization process effectively self-seals the tube, i.e. no discrete additional sealing steps need be applied at the locations designated 39A, 39B. In such an embodiment, this vacuum is held in place by applying a temporary seal to prevent air or fluid from reentering the inverted guide tube. When the vacuum is applied at the time of manufacture a temporary seal is created around the inner surface of the guide tube to maintain the vacuum prior to tube deployment. Alternatively, the vacuum seal can be a cap placed over the end of the nozzle 2 and removed prior to deployment. The seal can be a temporary seal as is commonly used in packaging processes. In that case the seal breaks when sufficient pressure is applied to the pressurization chamber 1 to begin deployment. Alternatively, the seal can be one that is applied to the end of the nozzle 2 either at the time of manufacture or by the user, and then removed just prior to deployment.
It is important to note that this vacuum sealing does not need to be perfect. While placement of a temporary seal can be used to maintain a higher vacuum, it should be noted that after the air within the inverted guide tube is removed by the vacuum, the guide tube 7 tends to naturally seal upon itself such that it is difficult for air to reenter the inverted tube prior to deployment. This is true for both the configuration shown in
The key element here is incorporation of a means to create a vacuum within the inner guide tube in order to reduce its overall profile which subsequently reduces the frictional forces that are created during deployment.
In another embodiment, a modified guide tube 7 is constructed using a flexible ribbed structure 54 constructed by spirally embedding or wrapping a continuous length of material, such as a thread, with a higher elastic modulus, i.e. a greater stiffness, than the guide tube wall material within or on the tube wall with spacing between the sections as shown in
In a non-segmented guide tube 7, it is the nature of the guide tube 7 to be straight when internally pressurized within a straight body lumen but at a fold, the tube wall at the inside apex of the bend is pressed against the opposing side of the tube, which can partially or completely occlude the lumen of the guide tube. When a segmented guide tube is internally pressurized and placed into a bend, the tube will partially fold within the bend at multiple defined bend points. In essence, the incorporation of the higher tensile strength or a stiffer material as disclosed here provides bend points for multiple small folds to occur within a bend at the incorporated stiffer material thereby reducing the likelihood of a single large fold forming and completely occluding the inner lumen of the tube.
We have found that shorter segment lengths result in a lower likelihood of such a single completely occluding fold occurring. The orientation of the segments is generally perpendicular to the tube axis. As a specific example, thread can be used to form the segmented guide tube. Thread is flexible and does not significantly hinder the deployment properties of the guide tube 7. There are numerous methods for fabricating these controlled bend points within a pressurized guide tube, including laminating one or more threads between tube layers or dip coating a like material layer over a tube with the structural threads in place.
The thread orientation within the tube may be of a variety of configurations.
In another configuration of a guide tube 7 with controlled bend points, rings perpendicular to the axis spaced at a set interval are molded into the tube. In some embodiments, the cross sectional areas enclosed by each ring is greater than the cross section of the tube wall thereby creating ribs along the outer surface of the tube wall. Controlled bend points with a guide tube may also be achieved by molding a tube with defined segments where the segments are separated by a short length where the cross sectional area is either increased or decreased relative to the nominal cross sectional area of the tube.
Frictional forces acting on deployment guide tube 7 arise when the inner and outer surface of the tube pass over each other during deployment. These can be reduced by reducing the coefficient of friction of the guide tube 7 surface. The tube surface can be modified in a variety of ways, including plasma energy treatment, bonding a wetting material to the surfaces such as polyvinylypyrrolidone (PVP), hyaluronic acid, or applying a surface coating such as parylene, etc. Another option to reduce the friction associated with the guide tube 7 is to apply a lubricating agent directly to the guide tube surface prior to deployment. Lubricating agents can be selected from a range of biocompatible lubricants as are well known in the art. In some embodiments, the guide tube surface can be modified to reduce the coefficient of friction by one of the above surface treatment methods and/or use of biocompatible lubricants that are known and acceptable for mucosal contact and are primarily comprised of glycerin, and propylene glycol.
As shown in
d shows the guide tube 7 fully deployed within a body lumen such as a colon. In the fully deployed state, the guide tube 7 is in a single wall tube configuration along its entire length. The valve 14 at the distal end 15 of the guide tube 7 is everted and open to the body lumen.
a-
a-
A further embodiment of the distal passive valve 14 is shown in
Alternatively to using a valve 14 to seal the distal end 15 of the guide tube 7 during eversion, viscous fluid such as silicone may be located within the lumen of the inner surface. Referring to
Other means can be used to form a valve or temporary seal at the distal end of the guide tube to promote eversion. Examples of alternative means to accomplish this are folding the distal end of the guide tube, use of a balloon, snare, pressure sensitive adhesive, adhesive, thermal or other applied energy tacking or welding, solvent bonding, elastic or inelastic band, and the like.
Various means have been disclosed separately here for achieving either guide tube deployment with low resistance pressure and for providing a distal valve to reduce the required deployment pressure and the volume of inflation fluid required. We also note that we have determined through bench-top testing that guide tube 7 deployment is further enhanced when these two features are used in combination. Specifically, we have found that, and we disclose here, that a combination of these two features using any one of the low resistance means disclosed here with any of the distal valve or sealing schemes disclosed here or elsewhere in the prior art provides performance superior to those concepts that exist in the prior art.
The function of the guide tube 7 may be enhanced with a distal valve 14 that does not open immediately during the guide tube 7 deployment so that the deployed guide tube 7 can be internally pressurized as the endoscope is being advanced within it. This is accomplished by the guide tube 7 deployment being stopped when the distal valve 14 has not yet reached but is in close proximity of the distal fold 36.
By not everting the last few inches of the guide tube 7 during deployment the distal valve 14 remains sealed. The proximal end of the guide tube 7 is sealed to the shaft of an endoscope by means such as that described by the description associated with
Pressurizing the guide tube 7 during endoscopic advancement provides a number of features to facilitate the insertion of the endoscope within the guide tube 7. The guide tube 7 has improved column strength to better fix the distal end in place as the endoscope is being advanced. In addition the opening in the lumen of the guide tube 7 is generally increased, thereby easing endoscope passage. A pressurized guide tube 7 also has the natural tendency to be in a straightened configuration. Therefore, when the deployed guide tube 7 is pressurized, the straightening effect of the guide tube 7 provides support to minimize or reduce the severity of bends within the colon caused by the advancing endoscope.
In one embodiment full deployment is temporarily stopped by fixing the distal end of the guide tube with a temporary seal known to those skilled in the art. Examples of such temporary seals are application of epoxy or adhesive at the distal end of the guide tube 7, thermally sealing the distal end of guide tube 7 or application of a stricture such as band or o-ring seal to the distal end of guide tube 7. The seals disclosed here are stronger than those described above, i.e. the burst pressure of these seals is generally in the range of 3-5 psi or above such that they will not open under normal deployment pressure. As a consequence, when the guide tube 7 is deploying, deployment stops when the distal seal is reached. Added pressure at this point would be noticeable to the operator and would result in opening of the pressure relief valve 3 if it is employed. When this point is reached the operator can advance the endoscope as described above. When the endoscope reaches the sealed end of the guide tube 7 it can be pushed through the distal end by via pushing force from the operator. Alternatively the operator can open the distal seal using the tools that are available via the distal end of the endoscope.
In yet another embodiment, the distal end of the guide tube 7 is permanently sealed. In this case the device is operated in the same manner with the endoscope inserted until it reaches the seal at the distal end. Once this is accomplished the operator uses a cutting tool in the endoscope to puncture this distal seal and advance the endoscope beyond the distal end of the guide tube 7.
In another embodiment the full deployment is temporarily stopped by mechanical means incorporated into the guide tube 7. An embodiment of a mechanical means to stop the deployment of the guide tube 7 during eversion is shown in
One configuration disclosed here maintains temporary static pressurization of the guide tube 7 by using a tether 23 to mechanically restrain the distal end of the guide tube 7 to thereby prevent or inhibit the distal end from everting during initial deployment. Means to achieve this function are shown in
The tether 23 may have various physical properties. In some embodiments, it can be flexible, and can have minimal elongation when subjected to normal loads of less than 10 pounds force. It may or may not have the ability to remain elongated under compressive force without buckling, or its length may have a combination of these attributes.
In one embodiment where the tether 23 has the ability resist compress forces at its distal end, the tether is withdrawn from the distal surface 36 of guide tube 7 prior to everting section of tube 7 where tether is secured. In one configuration shown in
In an alternative configuration, the proximal portion of the tether 23 resists compression and its distal end has low or nearly no compressive resistance properties. In this configuration the tether offers limited assistance pushing the distal end of the guide tube 7 while using lower than normal deployment pressure. The distal end of the tether 23 being very flexible does not significantly impede the eversion of the distal end of the guide tube 7. This configuration has the ability for the distal end of the guide tube 7 to be subsequently re-inverted to re-pressurize the lumen of the guide tube 7, while counter force is applied to the tether 23 as the endoscope is withdrawn from the guide tube 7 that remains stationary. In some embodiments, the compressive resistant tether 23 can be oriented in a straight configuration, and made from a creep resistant material so it does not take a curved shape when wound upon the deployment spool 6. Suitable material for the tether 23 includes spring wire, nitinol wire, and synthetics such as polyimide tube or solid core.
There are other means known to one skilled in the art to temporarily prevent the guide tube from fully everting during deployment. Examples of alternative means to accomplish this are a locking pin, locking catch, balloons, snares, pressure sensitive adhesion, banding, mechanical seals benefiting from internal pressure, diaphragms, etc.
An alternative means to advance the endoscope within a body lumen is to first deploy the guide tube 7 as previously described. With the guide tube 7 deployed within the body lumen, a semi-rigid guide is advanced down the entire length of the guide tube. The semi-rigid guide has a length greater than the guide tube 7 and a diameter less than the diameter of the working channel of an endoscope. With the semi-rigid guide in place, the guide tube is withdrawn from the body lumen while the semi-rigid guide remains fixed in place within the body lumen. An endoscope is now advanced within the body lumen over the semi-rigid guide.
As shown in
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. For example, features described in one embodiment can be used in another embodiment. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.
This application claims the benefit of U.S. Provisional Application No. 61/577,608 filed Dec. 19, 2011 titled “Endoscope Guide Tube” which is herein incorporated by reference in its entirety for all purposes.
Filing Document | Filing Date | Country | Kind |
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PCT/US2012/070661 | 12/19/2012 | WO | 00 |
Number | Date | Country | |
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61577608 | Dec 2011 | US |