The subject of the invention is a fistula drainage unit, the operation of which is based on a drainage, a seal set and a set of tubes with membranes. The suction and irrigating drainage system is dedicated for treatment for post-surgery and post-traumatic fistulas. A fistula should be understood as a pathological condition occurring in areas within a living body with a limited functional access thereto, e.g. as a result of separation of intestinal joints or other intra-abdominal or intra-tissue joints and connections.

A range of solutions exists, the design of which is included in the fistula drainage unit. The publication of the international application W02018152536A1 discloses a fistula treatment unit including an cap with a vacuum port, a spacer with an aperture, the first and the second anchor and a closing cap. The device is configured for vacuum generation through the vacuum port, the spacer aperture and an opening in the first distal anchor, wherein the spacer aperture is intended to seal the area between the first and the second anchor in the tissue, thus securing the device in place. The first anchor may also include many openings forming vacuum paths transferring the vacuum. The closing cap may also include an irrigating aperture, enabling irrigation of the fistula duct without the need to remove the device.

Another known solution is described in the American application US2020069850A, which discloses a device, method and system for wound treatment. The common point of the solutions lies in the use of multiple wound dressings combined with vacuum treatment of wounds. The vacuum treatment device includes a vacuum source and a controller. The vacuum source may include inlets configured for liquid flow from the dressings placed on the wound. The liquid flow paths may contain pressure sensors configured for pressure measurements within the liquid flow paths. The controller is intended to operate the vacuum source cooperating with at least one of the liquid flow paths.

Another known solution is described in the American application US2018250450 A1, which discloses a wound cleaning device, wherein irrigation liquid from a tank is connected with a dressing adapting to the wound. The exudate is transferred from the dressing thanks to the operation of at least one pump, wherein the exudate travels along a path passing through the dressing, while exudate suction and wound irrigation take place simultaneously, using means intended for simultaneous suction and wound irrigation.

Another known solution comes from the international application WO 2016/069890 A1 publication, which discloses a dressing and drainage device for vacuum therapy. The device includes a semi-permeable covering layer, adapted for covering of the wound of the patient, a porous dressing adapted to be placed between the semi- permeable covering sheet and the wound of the patient, and a drainage connection including a suction port with liquid connection with a porous dressing placed inside a semi-permeable covering sheet, as well as lines connected with the suction port on one end and adapted to be connected to a suction source on the other end.

Another known solution is disclosed in the publication of the international application WO 2021/161116 A1, which discloses drainage for spine surgery with the option of epidural medication injection. The drainage is provided with an additional injection port. The additional port enables delivery of a painkiller into the area upon the initial placement, as well as when the pipe remains in place. The surgical drainage according to the invention enables delivery of epidural post-operative analgesia to the patient, which improves the treatment of post-operative pain and eliminates the need of systemic drug delivery, as well as the related side effects.

Another known solution is presented in the international application WO 2013/131638 A1 publication, which discloses an invention related to a wound treatment kit, which includes a covering unit which can be attached to the skin surrounding the wound and is used to form enclosed space of the wound, and a suction connector which may be used to decrease the pressure within the wound space, wherein the covering unit is permeable for steam at least in some areas.

The objective of the invention is to provide more effective liquid removal with simultaneous drug delivery and fistula irrigation, as well as an improved seal around the fistula using a special design tube. The operation of the entire system is based on a suction pump continuously removing fluids from the fistula. This enables more effective treatment of the remaining part of the wound using a vacuum dressing.

The commonly used dressings, systems and fistula treatment methods are susceptible to leakages and clogging, which decrease the therapy efficiency, while increasing the suffering of the patients, causing mainly extensive inflammations, pain or even resulting in death.

The fistula drainage unit according to the invention includes a dressing made of porous foam and a fistula tube placed through the dressing. The dressing is made of a foam with open pores, including a fistula tube. The dressing is intended for attachment on the surface of the body by applying the external sealing film layer provided with a suction pump port of the dressing.

The fistula drainage unit according to the invention is characterised in that the drainage is provided with an external layer of polyurethane foam inside the fistula tube. The fistula tube is provided with a bottom flange and a top flange, wherein the top flange is provided with a ring adapted to attaching a through assembly lid, wherein the assembly lid is provided with a circumferential sealing ring at the point cooperating with the assembly flange, wherein the top part of the assembly lid is provided with a sealing valve containing the discharging drainage, placed within the central assembly tunnel. Two additional drains are placed inside the discharging drainage, wherein the transporting drainage is attached to the inner wall of the discharging drain, while the irrigating drainage can slide inside the discharging train using a spacer ring. The bottom flange of the fistula tube, on the other hand, includes a circumferential, flexible sealing membrane. In a preferable embodiment of the solution according to the invention, the drainage is connected to the suction pump via a port.

In another preferable embodiment of the solution according to the invention, a dressing made of foam with open pores is connected to a suction pump via a port.

In another preferred embodiment of the solution according to the invention, the fistula tube is provided with at least one, circumferential, open air duct in the side wall.

In another preferred embodiment of the solution according to the invention, the diameter of the irrigating drainage is up to 2/3 of the discharging drainage diameter, while the transporting drainage diameter is up to 1/3 of the discharging drainage diameter.

In another preferred embodiment of the solution according to the invention, the discharging drainage, the transporting drainage and the irrigating drainage include at least two symmetrical openings each.

The fistula tube may contain at least one circumferential, flexible, concentric, bottom sealing ring.

The previously used polyurethane dressing, in direct contact with the fistula wall, fistula tubes and adhesive sealing films have been supplemented with a three-piece drainage design, including a special design tube, thus forming a tight dressing for vacuum therapy of the fistula. In the past, a bag connected with a tube was used instead of a three point drainage. Bag overfilling and tube leakages were an unfavourable occurrence observed during such therapies. The previously known discharging systems, in the case of failure, contribute to the suffering of the patient and are inefficient, as they require frequent changes of the whole dressings. The lifetime of dressings used in the past is evaluated as 48 hours as a maximum. This solution ensures continuous cycle removal of the exudate. The drainage unit provides a sealed vacuum dressing with simultaneous, full circulation of three fluid types: fistula treatment and irrigation, as well as exudate fluid removal take place simultaneously.

The fistula drainage unit according to the invention provides a three point solution. Irrigation fluids and medication are delivered to the fistula simultaneously in the solution according to the invention, using two separate drainages, while the exudate is removed simultaneously through a third drainage acting as a suction drainage. This complex design of the drainage unit enables continuous treatment over longer periods of time while using a single dressing, without the need to replace any parts of the drainage unit.

The object of the invention is shown in an embodiment in the attached drawing, in which individual figures of the drawing represent as follows:

Fig.l. A view of the assembly drainage between the fistula tube and the assembly cover, side cross-section.

Fig.2. A drainage system with a seal, longitudinal cross-section.

Fig.3. A fistula drainage unit, cross-section according to the main symmetry axis

Fig.4. Fistula tube, view from below

Fig.5. Fistula tube with a thread,

Fig. 1. presents the assembly tunnel (23) formed between the sealing valve (8b) and the bottom flange (10b). A discharging drainage (2), shown in Fig. 2, is placed in the duct (23), including a polyurethane foam seal (6). Assembly flange (22) is mounted on the fistula tube wall (9). In this embodiment, a sealed connection between the assembly lid (8c) and the fistula tube (21) has been implemented by a pressed connection between the assembly flange (22) of the fistula tube (21) and the sealing ring (8a). In another embodiment, the assembly flange (22) may have the form of a threaded ring, while the fixing ring (8a) may be provided with spiral grooves corresponding to the thread, as shown in Fig. 5. Four open air ducts are visible in the presented embodiment, as also shown in Fig. 3. The fistula tube (21) contains a circumferential membrane (18) in the area of the fistula entry (16), sealing the air-filled (venting) ducts (7), as shown in Fig. 1.

Fig. 2 presents the complete set of drainages in a longitudinal section. The discharging drainage (2) contains two additional drainages. In the presented embodiment, the transporting drainage (5) is located on the left, while the irrigating drainage (4) is located on the right to the discharging drainage (2). In the presented embodiment a set of functional opening is visible at the length of individual drainages. The openings [17] of the transporting drainage (5) are located within the cross-section of the openings (13) of the discharging drainage (2), while openings (15) of the discharging drainage (4) are located below the fistula entry (16). As shown in the embodiment presented in Fig. 2, the external surface of the transporting drainage (5) is attached and connected to the internal surface of the discharging drainage (2). The irrigating drainage (4) is a moving drainage installed inside the discharging drainage (2) and slideable within the spacer ring (3). Sealing foam (6) is installed on the circumference of the discharging drainage (2), inside the assembly duct (23) near the fistula entry (16), as also shown in Fig. 3.

Fig. 3 shows a cross-section through the entire fistula drainage unit, including visible elements of the vacuum dressing and drainage elements. In the presented embodiment, the vacuum dressing is provided as polyurethane foam (11) with open pores, located within the area of the living tissue (14) within the fistula entry (16) shown in Fig. 1. In the presented embodiment, a layer of dressing film (12) is integrated with the port (lb) connected to a suction pump (la). A dressing layer comprising insulation for the open, alive structure (14) is applied onto the foam layer (11) within the area of the fistula entry (16) shown in Fig. 1. In the presented embodiment, the foam structure (11) includes a through opening for fistula tube (21) assembly, including the assembly lid (8c) installed on it. In the presented embodiment, the assembly lid (8c) is installed on the fistula tube (21) using a tight connection executed using a sealing ring (8a) cooperating with the assembly flange (22), as also shown in the embodiment in Fig. 1. The assembly tunnel (23) shown in Fig. 1 is visible between the sealing valve (8b) and the bottom flange (10b). The tunnel (23) contains a discharging drainage (2) containing two additional, functional drainages: a transporting drainage (5) for fluids, e.g. an antibiotic, and an irrigating drainage (4) enabling transport of e.g. physiological saline. In other embodiments, not shown in the figures, drainages (5) and (4) may transport different liquids. In the presented embodiment, the irrigating drainage (4) is slideable within the spacer ring (3) inside the discharging drainage (2), as also shown in Fig. 2. The spacer ring (3) enables vertical adjustment of the placement depth of the irrigating drainage (4) within the area of the fistula entry (16) shown in Fig. 1. In the presented embodiment, the discharging drainage (2) includes a port (lc) used to connect a suction pump (Id).

Fig. 4. presents the fistula tube (21), viewed from below. A set of stabilisers (20) of the assembly duct (23) is visible. In this embodiment, the assembly duct (23) is stabilised using four stabilisers (20) concentric with the horizontal and the vertical axis of symmetry. A sealing foam (6) jacket is placed inside the duct (23). In the presented embodiment, the bottom flange (10b) includes two bottom, flexible, circumferential sealing rings (19) concentric with the circumferential bottom flange (10b). In another embodiment, the bottom flange (10b) may include three or a different number of bottom sealing rings (19).

Fig. 5 presents a side view of the fistula tube (21), where the sealing ring (8a) is provided with spiral grooves matching the shape of the assembly flange (22) formed as a thread.

List of references: la. Suction pump of the dressing lb. Port of the suction pump of the dressing lc. Port of the suction pump of the discharging drainage ld. Suction pump of the discharging drainage

2. Discharging drainage

3. Spacer ring

4. Irrigating drainage

5. Transporting drainage

6. Polyurethane seal

7. Air duct

8a. Top sealing ring

8b. Sealing valve

8c. Assembly lid

9. Fistula tube wall

10a. Top flange

10b. Bottom flange

11. Polyurethane dressing foam

12. Dressing film

13. Discharging drainage openings

14. Alive tissue structure

15. Irrigating drainage openings

16. Fistula inlet

17. Transporting drainage openings

18. Fistula inlet sealing membrane

19. Bottom sealing ring

20. Stabilisers

21. Fistula tube

22. Assembly flange

23. Assembly tunnel