Medical systems, devices, and related methods

Abstract

In one example, a medical system can include a delivery tube configured to couple to a vacuum source and provide negative pressure to a distal portion of the delivery tube, and a porous body at the distal portion of the delivery tube, the porous body including a first section and a second section detachable from the first section.

Description

Technical Field

[0001] The present disclosure generally relates to medical systems, devices, and related methods that can be used to treat a subject. Aspects of the present disclosure relate to medical systems, devices, and methods for endoscopic medical procedures, such as applying negative pressure to tissue for wound treatment.

Background Art

[0002] Endoscopic and open surgical procedures of the gastrointestinal (GI) tract include, for example, among others, colectomy, bariatric surgery, esophagectomy, gastric bypass, and sleeve gastrectomy. As a result of these procedures, perforations, postoperative leaks, or other wounds may occur in the tract. There are limited treatment options for managing such wounds, which have a significantly high morbidity and mortality rate. The options include surgical reoperation and endoscopic placement of stents or clips. Surgery is relatively invasive and also has a high morbidity and mortality rate. Endoscopic stent placement is a less invasive option. However, the placed stent may move from the intended location and / or trap infective agents at the treatment site, inhibiting drainage.

[0003] The systems, devices, and methods of the present disclosure can correct some of the drawbacks described above or address other aspects of the art.

Summary of the Invention

Means for Solving the Problems

[0004] Examples of the present disclosure relate, among other things, to systems, devices, and methods for performing one or more medical procedures using medical systems and devices. Each of the examples disclosed herein can include one or more of the features described in relation to any of the other disclosed examples.

[0005] In one example, a medical system can include a delivery tube configured to couple to a vacuum source and provide negative pressure to a distal portion of the delivery tube, and a porous body at the distal portion of the delivery tube, the porous body including a first section and a second section removable from the first section.

[0006] In other aspects of the disclosure, the medical system can include one or more of the following features. The second section can extend circumferentially around the radially outermost surface of the first section, and the radially outermost surface can be radially outermost from the central longitudinal axis of the porous body. The system can further include a string coupled to the second section and extending from the porous body to the proximal portion of the delivery tube. The porous body can further include a third section extending circumferentially around the radially outermost surface of the second section, and the radially outermost surface of the second section can be radially outermost from the central longitudinal axis of the porous body. The system can further include a first string coupled to the second section and extending from the porous body to the proximal portion of the delivery tube, and a second string coupled to the third section and extending from the porous body to the proximal portion of the delivery tube. The delivery tube can be coupled to a vacuum source, the porous body can be cylindrical, and the central longitudinal axis of the porous body can be longitudinally aligned with the central longitudinal axis of the delivery tube. The system can further include a flexible overtube coupled to the second section, and the delivery tube can extend through the lumen of the flexible overtube.

[0007] In other aspects of the present disclosure, the medical system can include one or more of the following features. The first section can be cylindrical, and the second section can be wound around the first section. The first section and the second section can be separated by a perforation. The first section can be cylindrical and can include a central longitudinal axis. The second section can extend circumferentially around the outermost surface in the radial direction of the first section, and the outermost surface in the radial direction can be the outermost in the radial direction from the central longitudinal axis of the first section. The second section can be cylindrical and can include a lumen extending through the central longitudinal axis configured to receive the first section. A layer of mesh, adhesive, or agent can be disposed between the first section and the second section. The system can further include a delivery tube and a cylindrical overtube extending around the porous body, and the overtube can be configured to cover the porous body and the delivery tube. The system can further include a string coupled to the second section and the third section, and the string can extend from the sponge to the proximal portion of the delivery tube. The string includes a first portion coupled to the second section and the third section and having a length longer than the length of the delivery tube, and a second portion coupled to the third section and extending proximally to the proximal portion of the delivery tube. The first section, the second section, and the third section can be concentric and can have different thicknesses measured orthogonal to the central longitudinal axis of the porous body. The first string can be a different color than the second string.

[0008] In another aspect, the medical device can include a porous body including at least one perforation, a negative pressure conduit having an opening formed therein that is in fluid communication with the porous body and configured to apply a negative pressure to the porous body, and a string coupled to the porous body and extending from the porous body to a proximal portion of the conduit. The porous body can be configured to separate into discrete sections when the string is pulled proximally.

[0009] In other aspects of the present disclosure, the device can include one or more of the following features. The at least one perforation can extend longitudinally along the porous body. The conduit can be longitudinally aligned with a central cylindrical section of the porous body, and the at least one perforation can extend parallel to the longitudinal axis of the central section. The at least one perforation can include a first perforation and a second perforation, and the first perforation can be closer to the central longitudinal axis of the porous body than the second perforation.

[0010] In another aspect, a method of performing a medical procedure can include positioning a porous body adjacent to tissue at a target site, applying a negative pressure to the porous body, and pulling proximally a string coupled to the porous body to remove a first section of the porous body while a second section of the porous body remains positioned at the target site.

[0011] It can be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure as claimed. The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate exemplary aspects of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 4D

DETAILED DESCRIPTION OF THE INVENTION

[0013] The terms "proximal" and "distal" are used herein to refer to the relative positions of the components of an exemplary medical system and an exemplary medical device. As used herein, "proximal" refers to a position that is relatively close to the outside of the body or to the medical professional using the medical system or medical device. In contrast, "distal" refers to a position that is relatively far from the medical professional using the medical system or medical device or that is close to the inside of the body. The proximal and distal directions are labeled throughout the figures with arrows marked "P" and "D", respectively. As used herein, the terms "comprise", "comprising", "have", "include", or other variations thereof are intended to be construed as non-exclusive inclusion, such that a system, device, or method that comprises a list of elements includes not only these elements but also other elements not explicitly listed or inherent to it. Unless otherwise noted, the term "exemplary" is used in the sense of "example" rather than "ideal". As used herein, the terms "about", "substantially", and "approximately" indicate a range of values within + / - 10% of the recited value.

[0014] Endoluminal vacuum therapy (EVAC) has been proposed. In EVAC, negative pressure is delivered to a wound site within the GI tract, for example, through a nasogastric tube having a sponge at its distal end. The sponge is placed within a perforation, leak, or other wound by an endoscope. Negative pressure is then applied. However, devices and systems suitable for EVAC are limited.

[0015] Embodiments of the present disclosure include devices, systems, and methods for endoluminal vacuum therapy (EVAC). In an example, EVAC includes the intraluminal placement of a sponge or other similar material into a wound site, including a perforation, cyst, leak, anastomosis, etc. Placement of the material can be through a catheter, scope (endoscope, bronchoscope, colonoscope, gastroscope, duodenoscope, etc.), tube, or sheath inserted into the GI tract through a natural orifice. The orifice can be, for example, the nose, mouth, or anus, and the placement can be within any part of the GI tract, including the esophagus, stomach, duodenum, colon, or small intestine. The placement can also be within other organs accessible through the GI tract.

[0016] Next, reference is made in detail to the examples of the present disclosure described above and shown in the accompanying figures. Whenever possible, the same reference numbers are used throughout the figures to refer to the same or similar parts. Figure 1 shows a perspective view of an exemplary medical device 100 that includes a sponge 102 that can be used to assist in the healing of internal wounds, anastomoses, etc. within a subject. The sponge 102 may be substantially cylindrical and attachable, e.g., connectable, to a vacuum tube 104. The central longitudinal axis A of the sponge 105 may be aligned with the central longitudinal axis of the vacuum tube 104 (which is also shown as axis A in FIG. 1). The sponge 102 may be sized according to the patient's anatomical structure and can include a lumen or recess (not shown) for receiving the vacuum tube 104. The recess may be within the proximal end of the sponge 102. In some examples, the sponge 102 can include a curved, radially outermost surface 119. The sponge 105 may be flexible and configured to move through the tortuous path of a patient's body lumen.

[0017] The sponge 102 can include a plurality of concentric sections 116, 114, 112, 110, 108. Each section 116, 114, 112, 110, 108 may be separate from each other. The central section 116 may be shaped like a cylinder and can be directly coupled to the vacuum tube 104. For example, section 116 can have a shorter length than sections 114, 112, 110, 108 to accommodate the distal portion of tube 104 within the sponge 102. Each of the other sections 114, 112, 110, 108 can extend circumferentially around the central section 116 to form concentric ring-like cylindrical sections 114, 112, 110, 108 that are nested within each other. In some examples, each section 116, 114, 112, 110, 108 of the sponge 102 can be at a different distance from the central longitudinal axis A, and each section 116, 114, 112, 110, 108 can extend longitudinally in the direction of the central longitudinal axis A. In some examples, sections 116, 114, 112, 110, 108 can have the same thickness as measured in a direction perpendicular to the longitudinal axis A, and sections 114, 112, 110, 108 can have the same length as measured parallel to the longitudinal axis A. In other examples, sections 116, 114, 112, 110, 108 can have different thicknesses and / or different lengths. In some examples, the sponge 102 can include five sections (shown in FIG. 1), and in other examples, the sponge 102 can include two, three, four, six, seven, eight, nine, or any other suitable number of sections. Each section 114, 112, 110, 108 can contact the radially outer surface of the adjacent sections 116, 114, 112, 110, respectively, from the longitudinal axis A.

[0018] Sections 116, 114, 112, 110, 108 can be configured to move relative to each other such that one section 116, 114, 112, 110, 108 can be moved in a proximal - distal direction relative to the other sections 116, 114, 112, 110, 108 with little or no movement of the other sections 116, 114, 112, 110, 108. In some examples, a layer of mesh, adhesive, or agent may be disposed between each section 116, 114, 112, 110, 108 and an adjacent section 116, 114, 112, 110, 108, and this layer can facilitate removal of each section 116, 114, 112, 110, 108. In other examples, any other suitable material that joins adjacent sections together but allows them to be released from each other when an appropriate force is applied can be used between adjacent sections. Such materials can include an appropriate adhesive layer sandwiched between adjacent sections. In some examples, a drug may be laminated and / or sandwiched between adjacent sections and configured to be released from the sponge 102 when a radially outer layer from the longitudinal axis of the sponge 102 is removed, exposing the layer of drug. In some examples, the sponge 102 can be sized to fill a wound area 450 having a radius between approximately 1 cm and 7 cm and / or a depth between approximately 1 cm and 7 cm.

[0019] In embodiments of the present disclosure, the sponge 102 can be any suitable biocompatible material that can absorb and / or pass liquid by negative pressure. The material can be flexible, compressible, porous, hydrophilic, sterile, biodegradable, and / or disposable. The sponge material can be an open - cell foam having pores and channels internally. Suitable materials include polyurethane, esters, ethers, composite materials, and any medical - grade material.

[0020] The string or suture 106 may be coupled to the sponge 102 and may extend proximally from the sponge 102 to the proximal portion of the medical device 100. The string 106 may be coupled to each of the sections 108, 110, 112, 114 except for the central section 116. A length of the string 106 that is longer than the length of the medical device 100 (measured longitudinally) may be between each location where the string 106 is coupled to each of the sections 108, 110, 112, 114, thereby enabling each of the sections 108, 110, 112, 114 to be pulled proximally along the entire length of the medical device 100 without pulling any other of the sections 108, 110, 112, 114. The length of the string 106 between each location where it is coupled to each of the sections 108, 110, 112, 114 may be disposed between adjacent sections 108, 110, 112, 114. For example, the string 106 may be coupled to section 108, then to section 110, then to section 112, then to section 114, and the length of the string between each location where the string 106 is coupled to each section may be disposed between the sections (such as around a wound around the section). This additional length of the string 106 between each of the sections 108, 110, 112, 114 is configured to enable the user to pull section 108 proximally out of the patient's body without removing the remainder of the sections 110, 112, 114, 116, then proceed to pull the next radially outermost section (in this case section 110) proximally out of the patient's body without moving the remainder of the sections 112, 114, 116, and proceed in the same manner thereafter.

[0021] In some examples, the medical device 100 can include a single separate string coupled to each of the sections 108, 110, 112, 114, and thus, four strings 106 extend proximally from the sponge 102. In some examples, the medical device 100 can include a single string 106 coupled to each of the sections 108, 110, 112, 114, and each of the strings 106 can be a different color, such that a user removing a layer (section 108, 110, 112, 114) of the sponge 102 can identify which layer is being removed. In other examples, the string 106 can be replaced with a wire, tether, or extrudate. In some examples, the string 106 can be replaced with a set of concentric tubes extending from the sponge 102 to the proximal portion of the medical device 100, where each tube is coupled to a single section 108, 110, 112, 114. In this example, the tubes are flexible and configured to move through the patient's body.

[0022] The vacuum tube 104 may be cylindrical and have a central lumen (not shown) extending along the central longitudinal axis A of the vacuum tube 104. The vacuum tube 104 can have a length and width configured to extend through the working channel of an endoscope or other medical delivery device and may be flexible. In some examples, the vacuum tube 104 can include one or more holes in the distal portion of the vacuum tube 104 that includes the portion within the sponge 102. The vacuum tube 104 can be coupled to a vacuum source 120 at the proximal portion of the vacuum tube 104. The vacuum source 120 can supply a negative air pressure to the vacuum tube 101. The vacuum tube 104 may be coupled to at least the central section 116 of the sponge 102 and can supply a negative air pressure to the sponge 102. In some examples, the vacuum tube 104 can extend through the central portion 116 of the sponge 102. The vacuum tube 104 may be received within a recess in the proximal portion of the sponge 102 and, in some examples, the vacuum tube 104 may be coupled to the sponge 102 via an adhesive, suture, thread, and / or other attachment means.

[0023] In some examples, the medical device 100 can include an overtube (not shown) that can extend over the vacuum tube 104 and the sponge 102. The overtube can compress the sponge 102 such that the radially outermost surface from the longitudinal axis A of the sponge 102 is smaller when the sponge 102 is disposed outside of the overtube. The overtube can facilitate movement of the medical device 100 through the working channel of an endoscope or other medical device. Additionally, the overtube can prevent unwanted contact between the sponge 102 and the patient's tissue.

[0024] FIG. 2 shows a perspective view of the distal portion of an alternative embodiment of the medical device 200. The medical device 200 can have any of the features described above herein with respect to the medical device 100. The medical device 200 can include a vacuum tube 204 and a sponge 202, and can be coupled to a vacuum source 220 at the proximal portion of the medical device 200. In a manner similar to that described above herein with respect to the sponge 102, the sponge 202 includes concentric cylindrical sections 212, 214, 216. At least the central section 216 is directly coupled to the vacuum tube 204, the section 214 is coupled to a first string 223, and the section 212 is coupled to a second string 221. Each of the first string 223 and the second string 221 can extend from the sponge 202 to the proximal portion of the medical device and can be configured to be moved proximally to remove the sections 212, 214 of the sponge 202 from the patient's body. In some examples (shown in FIG. 2), the strings 221, 223 can be coupled to each of the sections 212, 214, respectively, at the proximal portions of the respective sections 212, 214. The strings 221, 223 can extend proximally outside of the vacuum tube 204.

[0025] Figure 3 shows a perspective view of the distal portion of another embodiment of medical device 300. Medical device 300 can have any of the features described above herein with respect to medical devices 100, 200. Medical device 300 can include a vacuum tube 304, a sponge 302, and a string 306. The vacuum tube 304 can be coupled to a vacuum source 320 at the proximal portion of the vacuum tube 304. The sponge 302 can include several sections 331, 332, 333, 334, 335, 336, and sections 331, 332, 333, 334, 335 can be wound around the central section 336. Each of the sections 331, 332, 333, 334, 335 can be wound around one or more adjacent and / or radially inner sections thereof, and sections 331, 332, 333, 334, 335, 336 can form a helix about the central longitudinal axis of the sponge 302. In some examples, a single rectangular sponge can be perforated to divide the sponge into sections 331, 332, 333, 334, 335, 336, and then this rectangular sponge can be rolled around a central section (such as section 336 in FIG. 3) to form the sponge 302. The string 306 can be coupled to each of the sections 331, 332, 333, 334, 335, 336, and a portion of the string that is the length of the medical device 100 is between each location where the string 306 is coupled to each respective section 331, 332, 333, 334, 335, 336.

[0026] Adjacent sections 331, 332, 333, 334, 335, 336 may be separated by perforations 361, 362, 363, 364, 365. The perforations 361, 362, 363, 364, 365 may be configured to allow the sections 331, 332, 333, 334, 335, 336 to separate from each other when the user pulls the string 306 proximally. For example, when the user first pulls the string 306 proximally, section 331 may be pulled proximally and the perforation 361 can allow section 331 to separate from section 332 without moving section 332 or any other section at all or only minimally. The user can then continue to pull the string 306 proximally to separate section 332 from section 333, then section 333 from section 334, and so on. In other examples, individual strings 306 may be coupled to each section 331, 332, 333, 334, 335, 336, whereby the user would need to pull one string to remove section 331, then a second string to remove section 332, and so on. In some examples (not shown), the central section 336 may be a sponge separate from the sponge 302. The perforations 361, 362, 363, 364, 365 can extend longitudinally, substantially parallel to axis A. In other examples, the perforations 361, 362, 363, 364, 365 are replaced by thinner regions or another form of weakening region between each section 331, 332, 333, 334, 335, 336 and can allow the adjacent sections 331, 332, 333, 334, 335, 336 to be released when an appropriate force is applied. Each section 331, 332, 333, 334, 335, 336 may be of any suitable size. In some examples, each section 331, 332, 333, 334, 335, 336 can extend circumferentially 360° around the central longitudinal axis of the vacuum tube 304. In other examples, each section 331, 332, 333, 334, 335, 336 can extend circumferentially less than 360° around the axis, such as section 331 shown in FIG. 3.The perforations 361, 362 can provide a means for a user to select the size of the sponge 302 before inserting the sponge 302 into the patient's body. Also, a layer of mesh, adhesive, agent, or other material may be used between adjacent sections 331, 332, 333, 334, 335, 336 as described above herein.

[0027] Next, reference is made in detail to a method of operating the medical devices 100, 200, 300. FIGS. 4A - 4D illustrate the operation of the medical device 100, but any of the medical devices 100, 200, 300 can be operated by the same method described hereinafter herein with respect to the medical device 100.

[0028] FIGS. 4A - 4D show side views of the medical device 100 in use within a patient's body lumen 452 (e.g., a portion of the gastrointestinal tract) to treat a wound area 450. To position the medical device 100 at the wound area 450 within the patient's body, the user can insert an endoscope (or another medical device) into the patient and visualize the wound area 450 using an image sensor (not shown) at the distal end of the endoscope, thereby identifying the location of the wound area 450. When the endoscope is positioned proximal to the wound area 450, the user can insert the medical device 100 into the working channel of the endoscope and move the medical device 100 distally through the working channel. In other examples, the medical device 100 may be positioned within the working channel proximal to the distal end of the endoscope before inserting the endoscope into the patient's body. In some examples, an overtube may be disposed between the medical device 100 and the working channel, and the overtube can prevent excessive bending, twisting, or other shape distortion of the medical device 100 within the working channel while the user moves the medical device 100 distally through the working channel. In other examples, the user may not need to use an endoscope and can insert the medical device 100 directly into the patient's body rather than within the working channel of a separate medical device.

[0029] With the distal portion of the endoscope positioned proximal to the wound region 450, the user can move the medical device 100 distally out of the working channel and place the sponge 102 into the wound region 450. The flexibility, compressibility, and shape of the sponge 102, as well as the flexibility of the vacuum tube 104, can facilitate the manipulation of the medical device 100 within the wound region 450. In some examples, the sponge 102 can bend, twist, and / or change shape to conform to the shape of the wound region 450. The user can then activate the vacuum source 120 to supply negative pressure to the sponge 102 through the vacuum tube 104, which can draw a portion of the wound region 450 towards the sponge 102. Once the medical device 100 is positioned within the wound region 450 and the vacuum pressure is supplied to the sponge 102, the user can then leave the sponge 102 and the vacuum tube 104 placed within the patient's body for approximately 48 - 72 hours. The negative pressure applied to the sponge 102 can also remove fluid and other materials from the wound region 450. In other examples, the sponge 102 may be left within the patient's body for any other period of time. The vacuum tube 104 can remain within the patient's body during treatment and extend from the patient to the vacuum source 120 through other openings within the patient's body, such as the patient's rectum, mouth, nose, other body orifices, or incisions. In some examples, an overtube can also remain within the patient's body during treatment and can cover a portion of the sponge 102 outside of the wound region 450.

[0030] As the wound area 450 heals, the wound area 450 can contract and become smaller. When the user desires to remove a section of the sponge 102 (such as after 48 to 72 hours have elapsed from the initial placement of the sponge 102 within the wound area), the user can first disconnect the vacuum tube 104 from the vacuum source 120 and supply physiological saline 460 to the vacuum tube 104 to deliver the physiological saline 460 to the wound area 450. FIG. 4B shows the physiological saline 460 being administered within the wound area 450. Although physiological saline 460 is shown in FIG. 4B, any suitable liquid known in the art may be used to fill the wound area 450 and facilitate removal of a portion of the sponge 102. The physiological saline 460 can facilitate release of the sponge 102 from the walls of the wound area 450. Once the physiological saline 460 is administered, the user can place the rigid tool 455 into the patient's body such that the distal end of the rigid tool 455 contacts section 110 of the sponge 102. The rigid tool 455 can prevent proximal movement of section 110 when the user pulls section 108 proximally. The rigid tool 455 can be a metal wire, tube, rod, or any other suitable relatively rigid member.

[0031] The wound area 450 is filled with physiological saline 460. After the rigid tool 455 is abutted against the section 110, the user can then pull the string 106 proximally to pull the section 108 proximally and remove the section 108 from the wound area 450. FIG. 4C shows that the section 108 has been pulled proximally from the wound area 450 and the rigid tool 455 is in contact with the section 110 to prevent the proximal movement of the section 110. FIG. 4C shows the use of the rigid tool 455, but the user can also remove the section 108 without the aid of the rigid tool 455 by simply pulling the string 106 proximally. After the section 108 is removed from the patient's body, the user can then reconnect and activate the vacuum source 120 to provide a negative pressure to the sponge 102, and the tissue in the wound area 450 can be drawn towards the section 110 (shown in FIG. 4D). This can enable the sponge 102 to consume less space within the wound area 450 and also enable the size of the wound area 450 to continue to decrease as the wound area 450 heals. The user can repeat these steps until the central section 115 is fully exposed to the wound area 450, and then the user can completely remove the medical device 100 from the patient when the treatment is complete. Note that the central section 116 can be removed from the patient's body by pulling the vacuum tube 104 proximally.

[0032] When treating tissue with any of the medical devices 100, 200, 300 described herein, it may be beneficial to remove a portion of the sponge after the patient's tissue has developed eschar formation or healed in another way. By removing sections of the sponges 102, 202, 302 from the area of tissue with eschar formation and enabling a new section of the sponge (or a portion of the sponge that has not yet contacted the tissue for treatment) to engage with the tissue, the tissue can heal more quickly.

[0033] Figures 4A - 4D show the sponge 100 being used to treat a wound area within a patient's body, but the present disclosure is not so limited. The sponges 102, 202, 302 and procedures discussed herein may be used to treat wounds, leaks, perforations, etc. in the upper gastrointestinal tract of a subject, the lower gastrointestinal tract of a subject, other lumens or cavities within a subject's body, on the outside of a subject, etc. The various aspects discussed herein can serve to reduce recovery time, reduce physician intervention, reduce the need and / or reliance on imaging or visualization for placing the sponge, reduce component costs, reduce risks to the subject, etc.

[0034] Additionally, the various aspects discussed herein can be packaged as a kit and used to treat a subject. Although the principles of the present disclosure are described herein with reference to illustrative aspects for particular applications, it should be understood that the present disclosure is not so limited. Those having access to the art and the teachings provided herein will recognize additional modifications, uses, aspects, and equivalents substitutions that are all included within the scope of the aspects described herein. Accordingly, the present disclosure should not be considered to be limited by the foregoing description.

Claims

1. A delivery tube configured to be coupled to a vacuum source and to provide negative pressure to a distal portion of the delivery tube; a delivery tube, and A porous body at the distal portion of the delivery tube, the porous body including a first section and a second section removable from the first section; a porous body, and A medical system comprising a string coupled to the second section and extending from the porous body to a proximal portion of the delivery tube.

2. The medical system according to claim 1, wherein the second section extends circumferentially around an outermost surface in the radial direction of the first section, and the outermost surface in the radial direction is the outermost in the radial direction within the first section from a central longitudinal axis of the porous body.

3. The medical system according to claim 1 or 2, wherein the porous body further comprises a third section extending circumferentially around an outermost surface in the radial direction of the second section, and the outermost surface in the radial direction of the second section is the outermost in the radial direction within the second section from a central longitudinal axis of the porous body.

4. The string is a first string, and the medical system further comprises a second string coupled to the third section and extending from the porous body to the proximal portion of the delivery tube, according to claim 3. The medical system described.

5. The medical system according to any one of claims 1 to 4, wherein the delivery tube is coupled to a vacuum source, the porous body is cylindrical, and a central longitudinal axis of the porous body is longitudinally aligned with a central longitudinal axis of the delivery tube.

6. The medical system according to any one of claims 1 to 5, further comprising a flexible overtube, wherein the delivery tube extends through a lumen of the flexible overtube.

7. The medical system according to any one of claims 1 to 6, wherein the first section is cylindrical and the second section wraps around the first section.

8. The medical system according to claim 7, wherein the first section and the second section are separated by a perforation.

9. The first section is cylindrical and includes a central longitudinal axis, the second section extends circumferentially around the outermost surface in the radial direction of the first section, the outermost surface in the radial direction is the outermost in the radial direction within the first section from the central longitudinal axis of the first section, the second section is cylindrical and includes a lumen extending through the central longitudinal axis configured to receive the first section, the medical system according to any one of claims 1 to 7.

10. The medical system according to any one of claims 1 to 9, wherein a layer of adhesive is disposed between the first section and the second section.

11. A delivery tube configured to couple to a vacuum source and provide negative pressure to a distal portion of the delivery tube, a delivery tube, A porous body at the distal portion of the delivery tube, the porous body including a first section and a second section removable from the first section. A cylindrical overtube extending around the delivery tube and the porous body, the cylindrical overtube configured to cover the porous body and the delivery tube, a medical system comprising.

12. The string is also coupled to the third section, the string, A first portion coupled to the second section and the third section, the first portion having a length longer than the length of the delivery tube. A second portion coupled to the third section and extending proximally to the proximal portion of the delivery tube, the medical system according to claim 3.

13. The medical system according to claim 3, wherein the first section, the second section, and the third section are concentric.

14. The medical system according to claim 4, wherein the first string is a different color from the second string.

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