Ligation band dispensing cap assembly and methods of use

A medical device for resecting a tissue. The medical device includes an elongate shaft having a distal end, a proximal end, and a plurality of channels extending therebetween. The medical device also includes a cap assembly disposed at the distal end of the elongate shaft. The cap assembly includes a housing having a proximal portion, a distal portion, and a cavity extending therebetween. The housing is configured to be transparent and includes a friction surface pattern disposed over a portion of an outer surface of the housing. The cap assembly further includes one or more ligation bands disposed on the proximal portion of the housing. The cap assembly also includes a wire interwoven between the ligation bands. The wire is further configured to roll at least one ligation band at a time towards the distal end of the distal portion.

FIELD OF THE DISCLOSURE

This disclosure relates generally to systems and methods for resecting tissue. More particularly, embodiments of the present disclosure relate to systems for endoscopic mucosal resection.

BACKGROUND OF THE DISCLOSURE

A treatment procedure for many gastrointestinal tract problems such as hemorrhoids, mucositis, early gastrointestinal cancer, and varices (vascular and lymphatic malformations) is Ligation Banding, an Endomucosal Resection (EMR) procedure. In this procedure, an elastomeric band is deployed over an undesired tissue such as a dysplastic/metaplastic lesion, a varix, or an internal hemorrhoid. The band exerts a compressive force on the tissue causing it to neck and form a polyp. The polyp may be resected using a snare loop or other resection device.

With conventional technologies, complications may arise. For example, a band can deploy at an angle, placing it over a smaller or larger region than desired. In such instances, the band may fail to compress the tissue properly, either producing a necked polyp, or increasing the risk of perforating the underlying muscular layer. As typically arranged, the bands are stretched over a housing and may require an operator to apply force for deployment. The present disclosure is directed to overcoming the disadvantages mentioned above as well as other problems in the art.

SUMMARY OF THE DISCLOSURE

In one aspect of the disclosure, a cap configured to be disposed at a distal end of an endoscope is disclosed. The cap includes a proximal portion, a distal portion, and a cavity extending between the proximal portion and the distal portions. The proximal portion may be configured to accommodate at least one ligation band on an outer surface thereof. The distal portion may taper towards a distal end of the cap. Further, the distal portion of the cap may have an outer surface configured to facilitate rolling motion of the ligation band thereon.

Another aspect of the disclosure is directed to a medical device. The medical device includes an elongate shaft having a distal end, a proximal end, and a plurality of channels extending there between. The medical device also includes a cap assembly coupled to a distal end of the elongate shaft. The cap assembly further includes a proximal portion, a distal portion, and a cavity extending between the proximal portion and the distal portion thereof. The proximal portion of the cap includes one or more ligation bands disposed over an outer portion of the cap assembly. The distal portion of the cap assembly has an outer surface configured to facilitate rolling of the ligation bands thereon. The cavity of the cap assembly includes a cavity having a region of low pressure to aspirate tissue that is to be resected with the device. In addition, the medical device includes a wire interwoven between the ligation bands. The wire is configured to pull at least one ligation band towards the distal portion of the cap assembly, may be extending through the cavity between the proximal and the distal portion of the cap assembly.

In yet another aspect of the disclosure, a method for resecting tissue is disclosed. The method includes introducing the medical device into a body cavity. The distal portion of the medical device may be positioned proximal to a tissue layer to be resected from a patient's body. The medical device includes an elongate shaft having a distal end, a proximal end, and a plurality of channels extending there between. The medical device also includes a cap assembly coupled to a distal end of the elongate shaft. The cap assembly further includes a proximal portion, a distal portion, and a cavity extending between the proximal portion and the distal portion. The proximal portion of the cap includes one or more ligation bands disposed over an outer portion of the cap assembly. The distal portion of the cap assembly has an outer surface configured to facilitate rolling of the ligation bands thereon. The cavity of the cap assembly includes a cavity for aspirating tissue to be resected by the device. In addition, the medical device includes a wire interwoven between the ligation bands. The wire configured to roll at least one ligation band towards the distal portion of the cap assembly and may extend through the cavity between the proximal and the distal portion of the cap assembly. The method may further include pulling the wire thereby pulling the ligation band. The ligation band may roll over the surface pattern of the cap and may be deployed over the desired tissue.

Additional objects and advantages of the disclosure will be set forth in part in the description which follows, and in part will be apparent from the description, or may become known by practicing the disclosure.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made to embodiments of the present disclosure, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The term “distal” refers to the end farthest away from a medical professional when introducing a device in a patient. The term “proximal” refers to the end closest to the medical professional when placing a device in the patient.

Overview

Embodiments of the present disclosure relate to systems and methods for resecting undesired tissue. For example, embodiments of the disclosed device may facilitate removal of deceased dead or other undesired tissue, such as hemorrhoids, mucositis, early gastrointestinal cancer, or varices (vascular and lymphatic malformations), including tissue disposed on, e.g., the mucosal walls of the colon, esophagus, stomach, or duodenum.

In some embodiments, a medical device may include a cap assembly configured for attachment to the distal end of a suitable introduction sheath, such as a catheter shaft, an endoscope, a laparoscope, a colonoscope, an ureterscope, or the like. The cap assembly may include a housing having a proximal portion, a tapering distal portion, and a cavity extending therebetween. The housing may have openings at its proximal and distal ends for allowing communication between the channels of the introduction sheath and the surrounding tissue. One or more ligation bands may be disposed on the proximal portion, and a varying-friction surface pattern may be configured on the surface of the distal portion of the housing. A wire may be interwoven between the ligation bands. The wire may be configured to roll at least one ligation band at a time toward the distal end of the distal portion of the housing.

Exemplary Embodiments

The embodiments disclosed herein are employed along with an endoscopic system, which functions as an introduction mechanism to introduce the disclosed embodiments to a target site within a patient's body. However, it may be noted that the embodiments of the present disclosure may be used along with other introduction devices, sheaths, or systems, such as trocars, catheter sheaths, laparoscopes, colonoscopes, ureterscope, or the like.

FIG. 1depicts an endoscopic system10. The system10includes a catheter shaft12, a cap assembly20, and a hub-handle assembly22. The catheter shaft12may have a proximal end14, a distal end16, and a plurality of working channels18extending through the catheter shaft12. The channels18may carry medical devices such as a vacuum suction mechanism, an endoscopic camera, light source, or the like. The cap assembly20is attached to the distal end16of catheter shaft12. One or more ligation bands24, and a number of such bands, generally 4, 5, 6, or 7 bands, may be disposed over cap assembly20. It should be appreciated that any number of bands may be disposed over cap assembly20. As known in the art, ligation bands24are resilient, formed of a material such as rubber, and dimensioned to constrict and resect tissue. One or more wires26extend from a rotatable knob28on the hub-handle assembly22, through one or more channels18in catheter shaft12, to the cap assembly20. For example, the one or more wires26may be coupled to a pulley (not shown) coupled to the rotatable knob28, such that rotation of the rotatable knob28can rotate the pulley to pull the one or more wires26. The wires26connect to the ligation bands24such that one band can be deployed at a time. Details of such a wire mechanism are provided in U.S. Pat. No. 5,913,865, which is expressly incorporated herein by reference in its entirety.

In addition to the rotatable knob28, the hub-handle assembly22includes several additional elements. A handle30allows the operator to hold the system10, and ports32permit the introduction of various medical devices into the channels18. Knobs and other controls34such as a steering mechanism and communication and control links to a computer system (none of which are shown) allow the operator to control the endoscopic system10.

FIG. 2is a side view of the cap assembly20. The cap assembly20includes a housing202attached to the distal end16of the catheter shaft12. The housing202includes a proximal portion204, distal portion206, and an internal cavity208. The distal portion206carries a varying-friction surface pattern210, as explained in detail below. In addition, one or more ligation bands212are disposed over the proximal portion204, and a wire214interweaves between the ligation bands212. The tripwire214operationally connects to the rotatable knob28, through the cavity208and through one of the channels18. For example, the tripwire214may be coupled to a pulley (not shown) that may rotate with the rotatable knob28.

The cap assembly20may be designed to either permanently or temporarily attach to the distal portion of catheter shaft12by an attachment mechanism. Permanent attachment mechanisms may include gluing, welding, soldering or the like, while temporary attachment mechanisms may include a snap-fit, screw-fit, luer-lock, press fit using a silicone component, or similar device formed into the cap assembly20. In some instances, the cap assembly20may be integral to the catheter shaft12. In an exemplary embodiment, as shown, the cap assembly20may have a screw-fit locking mechanism216at its proximal end.

The cap assembly20may be designed for multiple or a single uses. As a single-use device, for example, the cap assembly20may have temporary attachment mechanisms and may be stored in hermetically sealed, sterile packaging before use. A multiple-use device, however, may be sterilizably designed with materials able to withstand high temperature and pressure processing in devices such as an autoclave.

The dimensions of the cap assembly20may vary according to the desired application. For example, if cap assembly20is anally inserted to resect internal hemorrhoids, the dimensions of the cap assembly20may be considerably smaller than a similar device used in connection with treating esophageal varices.

Housing202may be a relatively short member (shorter than catheter shaft12) adapted to cover the distal end16of the catheter shaft12and facilitate dispensing ligation bands212. In general, the housing202may be a non-pliable, hollow tubular member, with cavity208in communication with a proximal opening218and a distal opening220. The proximal opening218may join internal channels18to the cavity208.

The proximal opening218may be dimensioned to fit over or mate with the catheter shaft12. In some instances, the cross-sectional shape of the proximal portion204may be circular, though other shapes may be employed as needed to be complimentary to the distal end16of the catheter shaft12. In addition, the cross-sectional dimensions of the proximal portion204may be uniform or may vary along its length.

The distal portion206may be configured with a generally decreasing taper from its proximal end to the distal opening220to facilitate dispensing the ligation bands212. Thus, the distal portion206may have a conical, hemispherical, or a funnel-like shape. The distal end of the distal portion206may be chamfered to further facilitate deployment of ligation bands212over a desired target tissue, and it may be made atraumatic to reduce the likelihood of inadvertent damage to the surrounding tissue. In addition, the distal end of the distal portion206may contain slots222, formed longitudinally in the surface of distal portion206. The wire214may be interwoven between the bands212and the slots222such that proximally pulling the wire214deploys one band212at a time.

The housing202may be configured to facilitate visualization of the tissue. In some embodiments, all or a portion of the housing202may be made from a transparent material. In some embodiments the entire housing202may be transparent, while other embodiments may include a transparent window or similar structure. Any of these alternatives allow an operator to view tissue around the housing202by way of a visualization device, such as an endoscopic camera19, carried within one of the channels18.

Surface pattern210is designed to provide a varying-frictional surface to facilitate the bands212to roll rather than slide while being dispensed. This characteristic is discussed in detail below. In the illustrated embodiment the surface pattern210may take the form of a spiral stripe extending the length of distal portion206.

Alternative forms of the surface pattern210are shown inFIGS. 3A-3F.FIG. 3Aillustrates a set of substantially circular stripes, formed circumferentially and spaced, evenly or irregularly, along distal portion206.FIG. 3Billustrates a criss-crossed pattern extending over the surface of the distal portion206.FIG. 3Cillustrates a solid pattern extending over the entire outer surface of the distal portion206. The solid pattern may be formed from a roughened surface having a pattern, regular or irregular, of varying frictional coefficients.FIGS. 3D and 3Eillustrate sets of circumferential stripes across the surface of distal portion206, the stripes being sinusoidal and zig-zag, respectively.FIG. 3Fillustrates a pattern of a plurality of patches arranged from the proximal to the distal end of the distal portion206. AlthoughFIG. 3Fshows the patches as substantially oval, it is contemplated that the patches may be of any shape including circular, square, triangular, irregular shape, and/or any other shape.

The surface pattern210may be transparent, that is, light can pass through the patterned areas without appreciable scattering, so that objects outside the housing are visible from within, semi-transparent, or translucent, depending upon the materials and techniques used to make the surface pattern210, described in detail in sections below. In some instances, the surface pattern210may be opaque; however in such embodiments, it may occupy a small enough percentage of the total surface area of the distal portion206such that it does not substantially obstruct the view of the endoscopic camera19. The surface pattern210may occupy any percentage of the total surface area of the distal portion206depending upon its transparency. For example, in some embodiments, a completely transparent surface pattern210may occupy 100% of the total surface area of the distal portion206. In some other embodiments, a translucent or opaque surface pattern210may occupy any percentage of the total surface area, including, for example, 25%, 20%, 15%, 10%, or 5% of the total surface area of the distal portion206.

Returning toFIG. 2, ligation bands212may be elastic rubber bands. The ligation bands212may be configured to roll over the surface pattern210. For example, the ligation bands212may have a square cross-section, which promotes rolling rather than sliding during deployment. The dimensions and elasticity of the ligation bands212may be determined by the desired application of the ligation bands212. For example, for large lesions, large ligation bands212may be needed, whereas for small varices, smaller ligation bands212may be used.

Wire214, as discussed, may be interwoven between the bands212. The wire214may be dimensioned to fit within the channel18and may be configured to pull the ligation bands212without any undesirable breakage or stretching. Although the present embodiment illustrates a single wire214, some embodiments may include multiple, wires.

FIG. 4illustrates deployment of the ligation bands212from housing202. Ligation bands212-1-212-5are arranged on the proximal portion204. The proximal end of a wire214extends distally from rotatable knob28(FIG. 1), or a pulley (not shown) coupled to the rotatable knob28, through distal opening220, and through one of a number of slots222. Wire214wraps around the first ligation band212-1, then returns distally to an adjoining one of slots222, wraps around the edge of that slot, and then extends proximally to the next ligation band212-2. That pattern continues until each ligation band212receives at least one wrap of wire214, such as a single wrap of wire214, or alternatively, a double wrap of wire214.

As the operator pulls the wire214proximally, the wire pulls the first ligation band212-1which may move from the proximal portion204to the distal portion206(initially, to the position shown inFIG. 4). When the band212-1reaches the distal portion206, it may experience friction generated by the high-friction surface pattern210. The frictional force acting on the contacting surface of the ligation band212-1, acting in collaboration with the force of tension exerted by the wire214, generates a torque on the band212-1, and initiates rolling motion of the ligation band212-1over the distal portion206. Specifically, the varying friction surface pattern over the distal portion has a coefficient of friction sufficient to generate a torque to support rolling of the ligation band over the distal portion. This increased frictional force is important when the ligation bands212are used in conditions where the bands212may be exposed to lubricants, which may be present for minimizing trauma to areas of tissue during intubation, and/or exposed to mucous in the gastrointestinal tract.

The housing202may be made of one or more suitable polymeric or metallic materials known in the art, for example the materials discussed above. In some implementations, a combination of materials may be employed. For example, the housing202may be made of a biocompatible, transparent, non-pliable material that can withstand high static and dynamic pressure exerted by the ligation bands212such as Poly(methyl methacrylate) (PMMA), ethylene tetrafluoroethylene (ETFE), polycarbonate, or the like.

The surface pattern210may be made by applying a clear, slightly adhesive coating on the regions marked by the surface pattern210. This coating may allow for visualization using the endoscopic camera19in addition to imparting a frictional surface to promote rolling. In some alternative embodiments, the surface pattern210may be produced by forming the surface pattern210on the housing202by abrasion. Sand blasting, etching, or similar processes may be used to abrade the housing202surface to give it a roughened finish. The abraded surface pattern210may provide sufficient friction to help ensure that ligation bands212roll rather than slide.

In some alternative embodiments, a two-shot molding process may be employed. In such embodiments, the surface pattern210may be made up of a friction-inducing polymeric material molded as flat strips or patches on the surface of the housing202. Alternatively, friction inducing metallic coatings may be applied on the housing202as the surface pattern210. For example, a metal or metal alloy powder may be attached to the surface of the housing202to form a high-friction surface pattern210. A person of ordinary skill in the art may contemplate various other techniques and materials to form the surface pattern210.

In some alternative embodiments, one or more surfaces of the housing202may include one or more micropatterns forming the surface pattern210. The one or more micropatterns may be formed on the one or more surfaces of the housing202during a molding process used to form the housing202. It is also contemplated that the one or more micropatterns may be formed on one or more surfaces of the housing202by a material removal process carried out on the one or more surfaces of the housing202. It is also contemplated that the one or more micropatterns may be added to one or more surfaces of the housing202by adding one or more materials to the one or more surfaces of the housing202. It is also contemplated that the one or more micropatterns may be formed using lithographic patterning methods, such as microlithography, nanolithography, photolithography, and/or any other suitable micropatterning process. A person of ordinary skill in the art may contemplate various other techniques and materials to create the micropatterning.

In some alternative embodiments, the surface pattern210may be formed by providing one or more low-friction regions on the housing202. For example, the housing202may be formed at least partially, or in some embodiments entirely, with one or more high-friction regions. The one or more high-friction regions may be formed in any suitable manner, such as by using the above-described methods and processes. Smoothing processes, such as grinding, polishing, and the like, may be carried out on one or more of the high-friction regions, to create one or more low-friction regions. Exemplary low-friction regions are shown between the regions having the surface pattern210inFIGS. 2-5C. Less friction is present between the ligation bands212and the low-friction regions than between the ligation bands212and the high-friction regions. The surface pattern210may be a fixed pattern that remains in a fixed position on the cap assembly20.

The ligation bands212may be made of elastic polymeric or rubber materials. The ligation bands212may expand/contract over a very wide range of circumferences and may exert a ligating force when contracted. In addition, the ligation bands212can maintain the described properties when subjected to storage, and the like. The ligation bands212may also be sterilized, and the bands212may be capable of maintaining the described properties during any sterilization.

To aid in detecting the position of ligation bands212within a patient's body, at least some portions of the ligation bands212may include radiopaque materials such as gold, palladium, platinum, tantalum, tungsten alloy, or polymeric materials loaded with radiopaque agents such as barium sulfate (BaSO4) or bismuth sub carbonate ((BiO)2CO3). Radiopaque materials are capable of producing a relatively bright image on a fluoroscopic monitor or other imaging device.

Ligation bands212may be coated with an antibacterial covering to inhibit bacterial growth on their surfaces. The antibiotic coating may contain an inorganic antibiotic agent, disposed in a polymeric matrix that may aid the antibiotic agent to adhere to the surface of the ligation bands212. A drug-releasing coating may be applied to the ligation bands212to assist in delivery of drugs to the severing site.

The bands212may have a frictional surface that may increase the friction between the bands212and the surface pattern210, thereby increasing the rotational torque, and hence angular motion of the ligation bands212. Alternatively, an adhesive coating may be applied on the ligation bands212to increase their surface friction along with the surface pattern210on the housing202. Additionally or alternatively, the bands212may have a roughened surface finish to improve tissue retention and prevent sloughing off over time.

FIGS. 5A-5Dillustrate use of the cap assembly20in performing an EMR ligation. As shown, an operator may introduce the endoscopic system10into a patient's body through natural anatomical openings or through incisions. Referring toFIG. 5A, the operator then steers the distal portion of the endoscopic system10proximate to the target tissue500. Visualizing the target tissue500through the endoscopic camera19placed in one of the channels18, the operator may place the distal portion206of the cap assembly200over the undesired tissue, such as a lesion, varix, or internal hemorrhoid.

Referring toFIG. 5B, the operator may then use vacuum suction though one of the channels18to draw tissue500into cavity208. The operator may draw tissue500until the tissue500completely blocks the view of the endoscopic camera19. This condition is conventionally referred to as ‘Red Out’, and may indicate the maximum amount of tissue500that can be accommodated within the cavity208. In alternative embodiments, a fluid such as gel, saline, hypertonic glucose, indigo carmine, ethylene blue or the like may be injected under the tissue to form a bleb, thereby raising the targeted tissue. In some cases, the polyp may be large and flat and multiple injections may be given around the polyp or directly into the middle of the polyp500. Next, the operator uses rotatable knob28to pull the wire214. The first ligation band212-1may then roll over the tapered distal portion206and deploy over the desired tissue500causing the tissue to neck and form a banded polyp500. The band may be in a fully closed position, including the entire targeted tissue.

Referring toFIG. 5C, the operator may then stop vacuum suction, and withdraw the cap assembly200from the polyp500. The process can be repeated multiple times until all ligation bands (212-1,212-2, and212-3) have been deployed, although only a single deployed band is shown. After ligating the required tissue500, the operator may choose to resect the polyp500, using a snare or similar conventional device, as shown inFIG. 5D. The operator may also retract the endoscopic system10from the patient's body.

Referring toFIG. 5D, it is also contemplated that blood supply to the tissue500may stop because of the compressive force of the band212-1, which may lead to the eventual death of the tissue500in hemostasis applications. The dead tissue500may be allowed to fall off naturally, or the operator may choose to resect the tissue500immediately, using a snare or similar conventional device, as in the case of removing polyps formed in EMR.

In another embodiment of the present disclosure, the tissue500may be a varix, such as one of a plurality of esophageal or anorectal varices, or a hemmorhoid. Varices and hemmorhoids may be removed in the same way that polyps, and tissue in hemostatis applications, are removed, as shown inFIGS. 5A-5D.

Embodiments of the present disclosure may be used in any medical or non-medical procedure. In addition, at least certain aspects of the aforementioned embodiments may be combined with other aspects of the embodiments, or removed, without departing from the scope of the disclosure.