GASTROSTOMY DEVICE WITH AN IMPROVED RETAINING ELEMENT

Abstract

A gastrostomy device (100) comprises a gastrostomy tube (200), and an inflatable retaining element (300) coupled to the tube (200) at or near a distal end (205) of the tube (200). The retaining element (300) comprises an inner layer (310) made of polyurethane, PUR, and an outer layer (315) made of polyamide, PA.

Claims

1. A gastrostomy device (100), comprising: a gastrostomy tube (200); and an inflatable retaining element (300) coupled to the tube (200) at or near a distal end (205) of the tube (200), characterized in that the retaining element (300) comprises an inner layer (310) made of polyurethane, PUR, and an outer layer (315) made of polyamide, PA.

2. The gastrostomy device (100) according to claim 1, wherein a portion (320, 330) of the inner layer of the retaining element (300) is coupled to a portion (220, 225) of the tube (200).

3. The gastrostomy device (100) according to claim 1, wherein the retaining element (300) is coupled to the tube (200) at two portions (220, 225) of the tube (200) spaced apart from each other.

4. The gastrostomy device (100) according to claim 1, wherein the retaining element (300) includes at least one tubular extension (320, 330) having a cross-section configured for coaxially sheathing the tube (200).

5. The gastrostomy device (100) according to claim 4, wherein the outer layer (315) made of polyamide extends at least partially on the at least one tubular extension (320, 330).

6. The gastrostomy device (100) according to claim 1, wherein the retaining element (300), in an inflated state, has a substantially ellipsoidal form.

7. The gastrostomy device (100) according to claim 1, wherein the retaining element (300) has a flat portion (340) substantially perpendicular to a longitudinal axis of the tube (200).

8. The gastrostomy device (100) according to claim 1, wherein a surface of the retaining element (300), when in an empty state, has an area substantially equal to an area of the surface of the retaining element (300), when in an inflated state.

9. The gastrostomy device (100) according to claim 1, wherein the gastrostomy device (100) further comprises: a protection sheath (610) sheathing the retaining element (300) in its empty state, wherein the retaining element (300) in its empty state is folded around the tube (200).

10. The gastrostomy device (100) according to claim 1, wherein the tube (200) comprises a gastric lumen (230) extending in a longitudinal direction of the tube (200) and a retainer lumen (235) extending in a longitudinal direction of the tube (200), wherein the retainer lumen (235) is in fluid communication with an interior space of the retaining element (300), and wherein the gastric lumen (230) extends to a distal end tip (210) of the tube (200) and is configured to let nutrition and/or medication and/or a gas pass through.

11. The gastrostomy device (100) according to claim 10, wherein the retainer lumen (235) has a cross-section forming an ellipse, wherein a minor axis of the ellipse aligns with a radially direction of a cross-section of the tube (200).

12. The gastrostomy device (100) according to claim 1, wherein the tube (200) comprises indication elements (240) disposed circumferentially and/or along a longitudinal direction of the tube (200).

13. The gastrostomy device (100) according to claim 12, wherein at least some of the indication elements (240) are visible from the outside of the tube (200), and/or wherein at least some of the indication elements (240) are integrated into a wall (245) of the tube (200), and/or wherein at least some of the indication elements (240) include a contrast agent.

14. The gastrostomy device (100) according to claim 1, wherein at least a part of the tube (200) is made of polyurethane, PUR.

15. Use of polyurethane, PUR, for an inner layer (310) of an inflatable retaining element (300) of a gastrostomy device (100), and polyamide, PA, for an outer layer (315) of the inflatable retaining element (300).

Description

[0049] Preferred examples of a gastrostomy device are described in greater detail with reference to the attached schematic drawings in the following, wherein

[0050] FIGS. 1A and 1B show a perspective view and a side view of a gastrostomy device, respectively, including a protection sheath sheathing a portion of the gastrostomy device,

[0051] FIG. 2 shows a side view of a gastrostomy device including a protection sheath sheathing a portion of the gastrostomy device and a trocar sheathed by an access sheath,

[0052] FIG. 3 shows a side view of a gastrostomy device including a protection sheath and an access sheath each sheathing a respective portion of the gastrostomy device,

[0053] FIGS. 4A to 4D show a distal end of a gastrostomy device in more detail, and in particular show a retaining element at a distal end of a gastrostomy device sheathed by a protection sheath and an access sheath at different states,

[0054] FIGS. 5A to 5C show a sectional side view of respective variants of a retaining element in an inflated state at a distal end of a gastrostomy device,

[0055] FIGS. 6A and 6B show exemplary double layer tubes from which a retaining element can be formed,

[0056] FIG. 7 shows a sectional side view of a retaining element and increased details thereof,

[0057] FIG. 8 shows a side view and a perspective view of a retaining element, and

[0058] FIGS. 9A and 9B show a cross-section of gastrostomy tubes of exemplary sizes CH10 and CH14, respectively.

[0059] The following detailed description of the schematic drawings focuses on the illustrated implementation variants of a gastrostomy device. The present disclosure is not limited to the above and below described and illustrated gastrostomy devices, but includes combinations of the described variants and implementation details of these gastrostomy devices.

[0060] FIGS. 1A and 1B show a perspective view and a side view of a gastrostomy device 100, respectively. The gastrostomy device 100 includes a gastrostomy tube 200, which forms the main component of the gastrostomy device 100 in a longitudinal direction thereof. At or near the distal end of the gastrostomy tube 200 is an inflatable retaining element 300 coupled to the tube 200. The distal end of the tube 200 and the retaining element 300 will be inserted into a body cavity of a patient, such as the stomach, when the retaining element 300 is in an empty state. Nevertheless, for a better understanding of the overall structure of the gastrostomy device 100 FIGS. 1A and 1B illustrates the gastrostomy device 100 with an inflated retaining element 300.

[0061] In order to facilitate inflation of the retaining element 300, the tube 200 comprises a first lumen, i.e. a retainer lumen, extending in a longitudinal direction of the tube 200. The retainer lumen is in fluid communication with an interior space of the retaining element 300. A connector arrangement 400 is provided at a proximal part of the tube 200. A connector of the connector arrangement 400 is in fluid communication with the retainer lumen and provides for coupling of filling means thereto, so that a fluid can be filled from the filling means through the retainer lumen into the interior space of the retaining element 300. Thereby the retaining element 300 is inflated (filled with the fluid) and achieves a form exemplarily shown in FIGS. 1A and 1B. The fluid may be water, a saline solution, glycerin, water-glycerin emulsion, air or other gas.

[0062] When inflated, the retaining element 300 retains the gastrostomy device 100 in the body cavity of the patient, such as the stomach. A user can pull the gastrostomy device 100, so that the retaining element 300 abuts against an interior wall of the body cavity, such as the stomach wall. For example, the user can pull the gastrostomy device 100 at the connector arrangement 400. Then the gastrostomy device 100 can be secured with an external retaining element 620. The external retaining element 620 is slidably arranged on the tube 200 but withstands a certain pulling or pushing force due to friction between the external retaining element 620 and an outer surface of the tube 200.

[0063] In order to facilitate such pulling, the tube 200 includes indication elements 240. Such indication elements 240 can be disposed circumferentially and/or along a longitudinal direction of the tube 200. The indication elements 240 can have an arbitrarily chosen form. For instance, some of the indication elements 240 are continually provided along a longitudinal direction of the tube 200 (not shown in FIG. 1A) or can be arranged at equal intervals along a longitudinal direction of the tube 200 as illustrated in FIG. 1A. Alternatively, the indication elements 240 can be arranged at logarithmic intervals in the longitudinal direction of the tube 200, where the distances between two adjacent indication elements 240 becomes smaller the closer they are located to the distal end tip 210 or to the retaining element 300. Furthermore, the indication elements 240 can also be provided with numerals, in order to indicate a distance to the distal end tip 210 or a distance to the retaining element 300. For example, the numerals can indicate such distance in centimeters or millimeters.

[0064] Furthermore, the tube 200 further includes a second lumen, i.e. a gastric lumen, extending in a longitudinal direction of the tube 200. The gastric lumen extends from a proximal end up to a distal end tip 210 of the tube 200. The gastric lumen is configured to let nutrition and/or medication and/or gas(es) pass through. Therefore, nutrition, medication and/or gas(es) can be led into or removed from the body cavity of the patient, such as the stomach. In order to facilitate supply of nutrition, medication and/or gas(es), a fitting 500 or fitting arrangement is provided at the proximal end of the tube 200.

[0065] FIGS. 1A and 1B further illustrate an exemplary sheath 610, 615 sheathing a portion of the gastrostomy device 100. Such sheath 610, 615 can be employed to form an access sheath into the body cavity, for example, into the stomach through the abdominal wall and stomach wall. Alternatively, such sheath 610, 615 may be a protection sheath for the retaining element 300, when it is in an empty state, for example, for transportation and before and during insertion into the body cavity. In order to remove the sheath 610, 615, it can be teared apart by pulling the two illustrated handles away from each other. The sheath 610, 615 is provided with a predetermined breaking line along the longitudinal direction of the sheath 610, 615.

[0066] FIG. 2 shows a side view of a gastrostomy device 100 and of a trocar 10, each including a sheath 610, 615 sheathing a portion of the gastrostomy device and the trocar, respectively. The illustrated gastrostomy device 100 and trocar 10 can be part of a gastrostomy kit, which is provided ready for use. The gastrostomy device 100 includes the same components as the gastrostomy device 100 of FIGS. 1A and 1B, so that the description of such components is omitted for brevity of the present disclosure.

[0067] The trocar 10 provided in the gastrostomy kit is inserted into an access sheath 615 and can be locked at a handle at the access sheath 615. The trocar 10 can then be used to puncture an opening through the abdominal wall and stomach wall of the patient by holding the trocar 10 at the knob 15 and pressing the sharp end of the trocar 10 through the abdominal wall and stomach wall. The trocar 10 can be made of stainless steel or PEEK (Polyether ether ketone) with a sharp distal pin end. When inserted, a distal end of the access sheath 615 enters the stomach of the patient. For example, the access sheath 615 can have a size of CH 10 to CH 20 (CH=Charrere, a measuring unit for the outer diameter of tubular devices; 1 CH is approximately 0.33 mm) and may include Teflon to facilitate relative movement of the access sheath 615 and the trocar 10.

[0068] This process can be observed with a simple endoscope provided into the stomach of the patient. Since the endoscope is only used to inflate the stomach with air and to provide an image from the inside of the stomach, the smallest available endoscope can be used. For example, a small tube endoscope (having a diameter of only 4.3 mm) can be used, which may be inserted through the nose of the patient. This helps reducing the risk of moving any infectious germs from the throat and/or esophagus of the patient into the stomach and is more comfortable for the patient.

[0069] Once inserted, the trocar 10 is removed, while the access sheath 615 maintains in the body of the patient. A valve in the access sheath 615 can close when the trocar 10 is removed, in order to prevent air from escaping from the inflated stomach. For instance, the valve can be disposed in a handle of the access sheath 615. Subsequently, the gastrostomy device 100 can be inserted through the access sheath 615.

[0070] As illustrated in FIG. 2, a distal end of the gastrostomy tube 200 is covered by a protection sheath 610. The protection sheath 610 can be identically constructed as the access sheath 615. However, the protection sheath 610 can be shorter than the access sheath 615. The protection sheath 610 protects the retaining element 300 provided at the distal end part of the tube 200.

[0071] In order to facilitate insertion of the gastrostomy device 100 into the patient's body cavity, the protection sheath 610 can be abutted against a proximal end of the access sheath 615. Thereby the tubular parts of the access and protection sheaths 610, 615 can be brought into alignment, so that both sheaths 610, 615 form a continuous tube. The distal end of the gastrostomy device 100, and in particular the distal end of the tube 200, is pushed through the protection sheath 610 into the access sheath 615 and further into the body cavity of the patient. This insertion can still be observed with the endoscope. By connecting the protection sheath 610 and the access sheath 615 a valve in the access sheath 615 (e.g. in the handle thereof) can be opened. Alternatively, the valve can be opened by the distal end of the tube 200 when pushed through the protection and access sheaths 610, 615.

[0072] When brought in place, the retaining element 300 is inflated. This retains the gastrostomy device in the body cavity. Then the access and protection sheaths 610, 615 can be removed from the patient and the gastrostomy device 100 by tearing them apart. Thereafter, the tube 200 can be pulled in a longitudinal direction away from the patient's body abutting the retaining element 300 to the body cavity wall (e.g., stomach wall). Then the gastrostomy device 100 is secured with an external retaining element 620. The external retaining element 620 can be a disk-like element that glides over an exterior surface of the tube 200. When pulling the gastrostomy device 100 away from the patient's body and, at the same time, pushing the external retaining element 620 along the tube 200 towards the patient's body, the abdominal wall and stomach wall are squeezed together and hold in place by both retaining elements 620, 300. In this position, a stoma is formed within two to four weeks.

[0073] FIG. 3 shows a side view of a gastrostomy device 100 including the two sheaths 610, 615 sheathing parts of the gastrostomy tube 200. In particular, FIG. 3 illustrates how the distal end 205 of the tube 200 and the retaining element 300 protrude from a distal end of the access sheath 615. This corresponds to the inserting process, where the empty retaining element 300 enters the body cavity.

[0074] The protection sheath 610 is illustrated spaced apart from the access sheath 615. However, it is to be understood, that during the insertion process, the protection sheath 610 may abut against the proximal end of the access sheath 615 forming a continuous passage for the gastrostomy tube 200.

[0075] FIGS. 4A to 4D show an enlarged distal end of a gastrostomy device 100, and in particular a distal end 205 of a gastrostomy tube 200 and a retaining element 300 sheathed by an access sheath 615 and a protection sheath 610 and further show different states of the retaining element. FIG. 4A illustrates how the access and protection sheaths 610, 615 form a continuous passage. This drawing further shows that a first portion (distal end portion) of the empty retaining element 300 protrudes from a distal end of the access sheath 615. This will take place while the access sheath 615 is provided through the abdominal wall and stomach wall of the body of the patient.

[0076] When pushed further, the entire empty retaining element 300 and the distal end tip 210 of the tube 200 will protrude from the distal end of the access sheath 615, as illustrated in FIG. 4B. In its empty state the retaining element 300 can cover the distal end tip 210 of the tube 200. Thus, the empty retaining element 300 forms a distal end of the gastrostomy device 100 during the insertion process. From the enlarged view of the distal end 205 of the tube 200 shown in FIG. 4C it is derivable that the retaining element 300 takes up space adjacent to the distal end 210 of the tube 200 in a longitudinal direction of the tube 200. This facilitates folding the retaining element 300 and providing it within the protection sheath 610. Since the distal end of the folded retaining element 300 can use the entire cross-sectional area of the protection sheath 610, kinks or other sharp folding edges of the retaining element 300 are avoided.

[0077] A surface of the retaining element 300 in its empty state has an area substantially equal to an area of the surface of the retaining element 300 when in its inflated state. In other words, the material of the retaining element 300 has almost no prolongation when being inflated. Thus, the empty retaining element 300 when being stowed requires more volume than, for example, an elastically extendable retaining element, such as the conventional retaining element made from elastic silicone.

[0078] FIG. 4D shows the distal end 205 of the tube 200, where the retaining element 300 is inflated. As illustrated in FIG. 4D, a portion 330 of the inner layer of the retaining element 300 is coupled to a portion 220 of the tube 200. Furthermore, the retaining element 300 is coupled to the tube 200 at two portions of the tube 200 spaced apart from each other, although only one portion 220 is visible in the drawing. The distal end 210 of the tube 200 protrudes from the retaining element 300. This facilitates the effusing of nutrition, medication and/or gas(es) from the distal end 210 of the tube 200.

[0079] FIG. 5A shows a cross-sectional view of a retaining element 300 in an inflated state at a distal end 205 of a gastrostomy tube 200. The retaining element 300 includes at least one tubular extension 320, 330 having a cross-section configured for coaxially surrounding the tube 200. In particular, a first tubular extension 320 surrounds a first portion 225 of the tube 200 and a second tubular extension 330 surrounds a second portion 220 of the tube 200.

[0080] The tube 200 includes a gastric lumen 230 and a retainer lumen 235 both extending in a longitudinal direction of the tube 200. Between the first portion 225 and the second portion 220 of the tube 200 an opening 250 in an outer skin of the tube 200 may be provided. This opening 250 provides for a fluid communication between the retainer lumen 235 and an interior space of the retaining element 300. Any fluid provided into the retainer lumen 235 can flow into the interior space of the retaining element 300, thereby inflating the retaining element 300.

[0081] The retaining element 300 comprises an inner layer made of polyurethane (PUR) and an outer layer made of polyamide (PA). The tubular extensions 320, 330 can be formed at least from the inner PUR-layer. A watertight connection is provided between the tubular extensions 320, 330 and the first and second portions 225, 220 of the tube 200, respectively. For example, the tubular extensions 320, 330 can be welded, adhered, shrink fitted, etc. onto the first and second portions 225, 220 of the tube 200, respectively. According to an example, at least portions 220, 225 of the tube 200 can be made of polyurethane (PUR), so that a solvent or heat bonding between the tubular extension 320, 330 (made also of PUR) with the respective portion 220, 225 of the tube 200 can be achieved easily. It is to be understood that the entire tube 200 can be made of PUR. The retaining element 300 can include an outer layer made of polyamide (PA). The outer PA-layer can extend at least partially on the at least one tubular extension 320, 330. In addition, the PA-layer can cover the entire tubular extensions 320, 330 as well as a part or all of an exterior surface of the tube 200. For instance, when the retaining element 300 is fixed to the tube 200, most parts of the gastrostomy device 100 can be dipped into a solution coating the retaining element 300 and the tube 200 with a PA-layer. Alternatively, the retaining element 300 is formed from a double layer tube consisting of PUR and PA layers and the tube 200 is also a double layer tube consisting of an inner PUR layer and an outer PA layer. In this case, the PA layer can be removed from the tube 200 at the two portions where the tubular extensions 320, 330 will be adhered, so that the PUR-layers of the tube 200 and the tubular extensions 320, 330 come into contact with each other.

[0082] FIG. 5A further shows that the tube 200 can have different cross-sections along a longitudinal axis of the tube 200. For example, with the opening 250 into the retainer lumen 235 the retainer lumen 235 can end. Therefore, the tube 200 may be formed between the opening 250 and the distal end tip 210 with a cross-section having only the gastric lumen 230. This allows a smaller outer diameter of the distal end of the tube 200, creating more space in particular in an area where the empty retaining element is disposed when folded.

[0083] Furthermore, the tube 200 may be provided with indication elements 240, such as symbols 241 or tick marks of a scale. Such symbols 241 are provided on a portion of the tube 200 facing towards the proximal end of the tube, i.e. a portion that will lie outside of the body of the patient when the gastrostomy device 100 is placed in the patient's body cavity. The indication elements 240 may be arranged circumferentially and/or in a longitudinal direction of the tube 200 at any desired distance. In a circumferential direction, the indication elements 240 can be uniformly distributed, such as three indication elements every 120 (not shown in FIG. 5A). The symbols 241 can be spaced apart from each other in the longitudinal direction of the tube 200 by a predetermined distance. For example, symbols 241 can be provided at equal intervals, such as 0.5 cm, 1 cm, 1.5 cm, or any other distance required to form a scale indicating a distance to the retaining element 300 and, in particular, a distance to the surface 340 of the retaining element 300 abutting the stomach wall. The symbols 241 may surround the tube 200 entirely (forming rings on a surface of the tube 200 as illustrated in FIG. 5A) or may be subdivided in a circumferential direction. The indication elements 240 can be printed onto the surface of the tube 200 or may be integrated into the tube wall of tube 200.

[0084] As can be derived from FIG. 5A, the retaining element 300, in an inflated state, can have a substantially ellipsoidal form. It is to be understood that the retaining element 300 does not need to have a perfectly symmetrical ellipsoidal form. For instance, the retaining element 300 may comprise one or more flat or plane surfaces 340, 345. It is particularly advantageous if a surface that will abut against the stomach wall of the patient has a flat or plane portion 340, since this provides good retaining properties. The retaining properties can be enhanced, if the flat or plane portion 340 is disposed substantially perpendicular to a longitudinal axis of the tube 200.

[0085] Alternatively, as illustrated in FIG. 5B, the flat or plane surface 340 of FIG. 5A may be bent inwardly, i.e. towards a center of the retaining element 300. This can be achieved by moving the proximal tubular extension 330 closer to the distal end of the tube 200 before adhering the proximal tubular extension 330 to the tube 200. Alternatively or additionally, the retaining element 300 may be fabricated as having a bulge that is maintained due to the form durability of the PUR- and PA-layers of the retaining element 300, where the proximal tubular extension 330 lies closer to a center of the retaining element 300. This provides additional flexibility for the gastrostomy device 100 when the retaining element 300 abuts against the wall of the body cavity, such as the stomach wall, around the stoma. Thus, the wall of the body cavity is less irritated by the proximal tubular extension 330 and/or the surface 340 of the retaining element 300.

[0086] Additionally or alternatively, the retaining element 300 can be provided with a bulgy form on the opposite (distal) side, i.e. at surface 345. Likewise, the distal tubular extension 320 may be adhered to the tube 200 resulting in the bulgy form of the retaining element 300 and/or the retaining element 300 may be fabricated with such bulgy form.

[0087] Also additionally or alternatively, the retaining element 300 can be provided with a flat or plane surface 345 on its distal side and the distal tubular extension 320 is brought closer to the proximal end of the tube 200 before adhering the distal tubular extension 320 to the tube 200. For instance, the flat or plane surface 345 can protrude further to a distal side of the gastrostomy device 100 than the distal end tip 210 of the tube 200. Such form of the retaining element 300 is illustrated in FIG. 5C. This allows providing the distal end tip 210 closer to the center of the retaining element 300. This form of the retaining element 300 and, in particular, the surface 345 of the inflated retaining element 300 then facilitates keeping the distal end tip 210 away from a corresponding wall of the body cavity (otherwise pricking into the wall of the body cavity), such as the stomach wall. Thus, the wall of the body cavity on the distal side of the retaining element 300 will not be irritated (or less irritated) by the tube 200 (particularly its distal end tip 210) and/or the surface 345 of the retaining element 300.

[0088] It is to be understood that distal side surface 345 of the retaining element 300 is not limited to the form illustrated in FIG. 5C. The flat or plane surface 345 can instead be flush with the distal end tip 210 of the tube 200. Furthermore, it is also understood that the proximal side (surface 340) of the retaining element 300 can be formed corresponding to the distal side (surface 345) of the retaining element 300.

[0089] In order to fabricate any of these retaining elements 300, a double layer tube may be formed as illustrated in FIGS. 6A and 6B. For example, a double layer tube can be fabricated by coextrusion of PUR forming an inner layer 310 of the tube and PA forming an outer layer 315 of the tube. FIG. 6A shows an exemplary tube having an outer diameter of approximately 5.6 mm and an inner diameter of approximately 5 mm. The thickness of the inner PUR-layer 310 can be between 0.1 mm and 0.4 mm, preferably 0.2 mm, and the thickness of the outer PA-layer 315 can be between 0.05 mm to 0.2 mm, preferably 0.1 mm. Such tube can be used to form a retaining element 300 that fits onto (can be coupled to) a tube 200 of size CH 10.

[0090] According to another example illustrated in FIG. 6B, the double layer tube may have an outer diameter of approximately 6.6 mm and an inner diameter of approximately 6 mm. The thickness of the inner PUR-layer 310 can be between 0.1 mm and 0.4 mm, preferably 0.2 mm, and the thickness of the outer PA-layer 315 can be between 0.05 mm to 0.2 mm, preferably 0.1 mm. Such tube can be used to form a retaining element 300 that fits onto (can be coupled to) a tube 200 of size CH 14.

[0091] Such double layer tube is then expanded or widened to take the form of the retaining element 300, as shown in FIG. 7. Optionally, the double-layered tube can be elongated or stretch formed before widening. After (elongating and) curing, the retaining element 300 can be taken out of a mold or tool. Any remaining parts of the double layer tube at one or both ends of the retaining element 300 can be cut to a desired length, thereby providing the proximal tubular extension 330 and/or the distal tubular extension 320.

[0092] During the elongating the diameter of the double-layered tube decreases. By elongating adjacent portions of the double-layered tube to a different extent, varying diameters of the double-layer tube can be achieved. This allows forming tubular extensions 320, 330 that fit onto different portions of tube 200, such as portions 220, 225 (FIG. 5A) having different diameters. It is to be understood that both tubular extensions 320, 330 can have the same inner diameter, so that they fit onto a tube 200 having a continuous outer diameter. Furthermore, elongating the double-layered tube allows fabricating retaining elements 300 for tubes 200 of different sizes, e.g. CH 8 to CH 12, from the same double-layered tube, such as the double-layered tube illustrated in FIG. 6A. Likewise, the double-layered tube illustrated in FIG. 6B may be used to fabricate retaining elements 300 for tubes 200 of sizes between CH 12 and CH 20. It is to be understood that a specific double-layered tube (having a specific diameter) can be employed only for a retaining element 300 for a certain tube size.

[0093] Only as an example, a first tubular extension 320 of the retaining element 300 may have an outer diameter between 3.9 mm and 4.3 mm, preferably 4 mm, an inner diameter of approximately 3.7 mm and a wall thickness of approximately 0.15 mm. Similarly, a second tubular extension 330 may have an outer diameter between 4.4 mm and 5 mm, preferably 4.5 mm, an inner diameter of approximately 4.2 mm and a wall thickness of approximately 0.15 mm. As can be derived from these dimensions, the first tubular extension 320 may have a smaller inner (and outer) diameter than the second tubular extension 330, in order to fit onto a smaller portion of the tube 200 at a distal end 205 thereof (see FIG. 5).

[0094] Furthermore, the retaining element 300 may have a substantially elliptical cross-section, a bulgy cross-section or other partially round form. For instance, the outer ends (in a radially direction) of the retaining element may be curved, for example having a radius between 2.5 mm and 10 mm, preferably 6 mm, so that the retaining element 300 is approximately 5 mm to 20 mm deep, preferably 8 mm to 15 mm deep, and most preferably 12 mm deep (in a longitudinal direction of the tubular extensions 320, 330). The maximum radial extend of the retaining element 300 can be between 20 mm and 35 mm, preferably between 22 mm and 30 mm, and most preferably ca. 26 mm. Since the double layer tube is widened to form the retaining element 300, the wall thickness varies from the tubular extensions 320, 332 the radially maximal spaced portion of the retaining element 300. At the radially maximal spaced portion of the retaining element 300 (cf. Detail C in FIG. 7) the wall thickness can become approximately 0.025 mm thin.

[0095] As can be further derived from FIG. 7, the tubular extensions 320, 330 can migrate to the retaining element 300 with a curvature, for example a radius between 2 mm and 3 mm, preferably 2.5 mm. Alternatively, the transition between tubular extensions 320, 330 and the retaining element 300 may be substantially perpendicular. Between this transitioning portion and the curved radially maximal spaced portion (outer end) of the retaining element 300 may be a flat or plane surface 340, 345. Flat or plane surface 340 is configured for abutting against a stomach wall of the patient. Alternatively, the surface 340 may have a rather bulgy form (FIG. 5B). Likewise, surface 345 can be a flat or plane surface or can have a rather bulgy form (FIG. 5C).

[0096] FIG. 8 schematically shows a side view and a perspective view of a retaining element 300 thus formed. Only one flat or plane surface 345 of the retaining element 300 is visible. It is to be understood that the retaining element can also be fabricated without a flat or plane surface.

[0097] FIGS. 9A and 9B show cross-sections of gastrostomy tubes 200 of sizes CH10 and CH14, respectively. According to a first example shown in FIG. 9A, an outer diameter of the tube 200 can be approximately 3 mm and an inner diameter can be approximately 2 mm.

[0098] The tube wall 245 thus formed creates a gastric lumen 230. Within the tube wall 245 can be a retainer lumen 235. Both lumens 230, 235 extend in a longitudinal direction of the tube 200, wherein the gastric lumen 230 extends to a distal end tip 210 of the tube 200 and the retainer lumen 235 is in fluid communication with an interior space of the retaining element 300. Such fluid communication can be achieved by an opening (not shown in FIG. 9A) through the tube wall 245 into the retainer lumen 235 (from an exterior side of the tube 200). The retainer lumen 235 can have a cross-section forming an ellipse. Such ellipse may have a minor axis that aligns with a radially direction of a cross-section of the tube 200, as shown in FIG. 9A. The minor axis of the ellipse may have a length of approximately 0.4 mm, and a major axis of the ellipse may have a length of approximately 0.6 mm. The center of the ellipse may be about 1.1 mm from the center of the cross-section of the tube 200.

[0099] Due to the retainer lumen 235 the cross-section of the gastric lumen 230 has an indent. This indent may be formed by two curved sections moving towards the center of the tube 200, each having a radius of about 0.2 mm and an intermediate section with an opposite curvature with a radius of approximately 0.45 mm. This intermediate section can be substantially parallel to the corresponding part of the ellipse of the retainer lumen 235. Therefore, the indent into the gastric lumen 230, i.e. the interior surface of the tube wall 245 at the most indenting position, may be spaced apart from the center of the tube 200 by approximately 0.7 mm.

[0100] Furthermore, integrated into the tube wall 245 may be indication elements 240. For example, FIG. 9A depicts indication elements 240 in the form of markers 242, which are arranged in a circumferential direction. The markers 242 can be uniformly distributed, such as three markers 242 every 120. The markers 242 can have an approximately rectangular or elliptical cross-section having dimensions of approximately 0.5 mm and 0.25 mm. The distance between a marker 242 and an exterior surface of the tube wall 245 may be about 0.08 mm, while a distance between the marker 242 and an interior surface of the tube wall 245 (the surface of the gastric lumen 230) may be about 0.04 mm. The markers 242 may extend over the entire length of the tube 200 (in a longitudinal direction of the tube 200).

[0101] According to a second example shown in FIG. 9B, an outer diameter of the (CH14) tube 200 can be approximately 4.2 mm and an inner diameter of approximately 3 mm.

[0102] The tube wall 245 thus formed creates a gastric lumen 230. Within the tube wall 245 can be a retainer lumen 235. The retainer lumen 235 can have a cross-section forming an ellipse. Such ellipse may have a minor axis that aligns with a radially direction of a cross-section of the tube 200, as shown in FIG. 9B. The minor axis of the ellipse may have a length of approximately 0.6 mm, and a major axis of the ellipse may have a length of approximately 0.8 mm. The center of the ellipse may be about 1.45 mm from the center of the cross-section of the tube 200.

[0103] Due to the retainer lumen 235 the cross-section of the gastric lumen 230 has an indent. This indent may be formed by two curved sections moving towards the center of the tube 200, each having a radius of about 0.3 mm and an intermediate section with an opposite curvature of a radius of approximately 0.65 mm being substantially parallel to the corresponding part of the ellipse of the retainer lumen 235. Therefore, the indent into the gastric lumen 230 may be closer to the center of the tube 200 than the remaining interior surface of the tube wall 245.

[0104] Furthermore, integrated into the tube wall 245 may be indication elements 240. For example, FIG. 9B depicts indication elements 240 in the form of markers 242 may be arranged in a circumferential direction. The markers 242 can be uniformly distributed, such as three markers 242 every 120. The markers 242 can have an approximately rectangular or elliptical cross-section having dimensions of approximately 0.8 mm and 0.3 mm. The distance between a marker 242 and an exterior surface of the tube wall 245 may be about 0.08 mm, while a distance between the marker 242 and an interior surface of the tube wall 245 (the surface of the gastric lumen 230) may be about 0.04 mm. The markers 242 may extend over the entire length of the tube 200 (in a longitudinal direction of the tube 200).

[0105] Alternatively or additionally to markers 242 integrated into the tube wall 245, symbols 241 (not shown in FIGS. 6A and 6B) can also be printed onto an exterior surface of the tube wall 245.

[0106] The above described aspects, variants and implementations of a gastrostomy device do not limit the present disclosure. Any details described with respect to one of the illustrated gastrostomy devices may also be implemented or applied to another one of the described gastrostomy devices.