ES2728797B1 - Endoscopic accessory for ligation of lesions - Google Patents

Description

DESCRIPTION

Endoscopic accessory for ligation of lesions

TECHNICAL SECTOR

The present invention belongs to the field of medical-surgical equipment and more specifically to that of endoscopic devices. It refers to an accessory to perform ligatures of lesions in the mucosa and submucosa of a hollow organ of the body, such as those of the digestive tract.

STATE OF THE ART

Endoscopic procedures for the diagnosis and treatment of digestive pathologies, the biliary tree, the vascular system and other organs of the human body have developed to become common procedures in all hospitals and medical centers.

Digestive endoscopy is a diagnostic-surgical technique that is practiced through natural orifices of the digestive system, the mouth or the anus, using the assistance of flexible endoscopes of different characteristics and lengths that are equipped with a light source, a camera of video and a working channel through which different tools can be introduced. All this allows the medical team the endoluminal diagnosis of the pathology and its treatment. These techniques are known as minimally invasive since they avoid large interventions and therefore allow a recovery period with much fewer comorbidities and being more comfortable for the patient.

Endoscopic treatment of lesions currently encompasses a variety of techniques such as electrical cautery, laser photocoagulation, thermotherapy by application of heat probes, and sclerotherapy, which involves injecting a drug into a target vessel, varicose or not. , by means of a needle that is passed through the working channel of the endoscope. Another widely used and increasingly promising technique is lesion ligation, where the mucosal and submucosal tissue is aspirated and strangulated at its base using an elastic band.

Patent ES2146310, among others, describes a type of endoscopic device to perform ligatures composed of a cap on which a plurality of elastic bands whose purpose is to tie the lesions at the base. A string is placed under the bands and inserted into the working channel of the endoscope. The proximal end of the string is wrapped around a wheel on the outside of the endoscope. The wheel acts as a rope drive mechanism, releasing the bands one by one. The cap is placed at the distal end of the endoscope, covering the entire section of the scope and leaving the preloaded bands in a stretched state, which conditions that the endoscope has a rigid portion at its end, thus making insertion in the areas difficult. narrower or more angled, such as the pharyngoesophageal junction (anatomical point called Killian's mouth) and therefore increasing the risks of the test. Said rigid section worsens maneuverability also at marked working angles, proving impossible to use in digestive tracts such as the right colon (anatomical region of the ascending colon and cecal cul-de-sac) and lengthening the test time on other occasions, since each Once the therapy is to be applied after the limited number of preloaded bands is exhausted, the endoscope must be removed and reintroduced with a cap, thus having to re-locate the lesion and position the endoscope in front of it, a task that when the active bleeding can be long, complicated and not without risks.

The size of the cap is also limited to a diameter similar to that of the endoscope, so it is not possible to ligate larger lesions.

OBJECT OF THE INVENTION

The object of the invention therefore is to provide an accessory for ligating lesions with bands that allows an easy approach, suction and firing of the bands quickly, easily, safely and without the need to exchange the endoscope or lose position.

To this end, the invention proposes an endoscopic accessory comprising two flexible tubes, one inner and the other concentric outer, movable between them and defining a distal end and a proximal end and a conduit to connect to a vacuum pump at the proximal end, comprising also a stent fixed to the distal end of the inner tube, said stent having a conical section in its proximal part and another cylindrical in the distal part, the stent being covered, at least between the openings of its weft, by a plastic or silicone material and provided with one or more elastic bands for treating injuries and a rope mechanism to release them. Advantageously, the The angle of inclination of the conical section, once the stent has been opened, is between 20 ° and 45 °.

Preferably, the tubes comprise Teflon, polyurethane or polyethylene and the stent nitinol, chromium cobalt, stainless steel, titanium, iridium or alloys of titanium and iridium.

Optionally, wedge-shaped silicone membranes adhered to the stent in its widest part can be incorporated above the bands to prevent them from moving during the closure of the device. Preferably, a valve is provided within the proximal end of the outer tube in such a position as to prevent the passage of air into the conduit.

Optionally, a conical termination of biodegradable material can be included at the distal end of the outer tube to facilitate insertion and movement within the working channel of the endoscope. If desired, a thread may be further included at the proximal end of the outer tube adapted to secure the accessory to an endoscope and / or a thread at the proximal end of the inner tube adapted to secure endoscopic accessories.

It is possible to apply the accessory in larger lesions than with previous techniques, since the stent can be presented once opened with a diameter greater than that of the endoscope. Another advantage of the invention is that the stent can be encapsulated and removed from the endoscope in case of wanting to interrupt the treatment even without having triggered all the bands, so that they can be reused at another point in the endoscopic test. Furthermore, when used through the working channel, its use is not influenced by the angulations of the colon and therefore it is possible to access deep areas of the digestive tract, such as the right colon.

BRIEF DESCRIPTION OF THE FIGURES

In order to help a better understanding of the characteristics of the invention according to a preferred example of a practical embodiment thereof, the following description of a set of drawings is attached where, with an illustrative and non-limiting nature, the following has been represented :

Figure 1 is a general view of the accessory in an example of implementation with the drive wheel located on the side wall of the inner tube.

Figure 2 is a view of the accessory according to the previous example in its open position.

Figure 3 shows the different steps in the use of the accessory.

Figure 4 shows the position of the device relative to the endoscope.

DETAILED DESCRIPTION OF THE INVENTION

The accessory of the invention comprises an inner flexible tubular element 1a and an outer concentric element 1b of the same material, a suitable medium grade plastic, such as Teflon, polyurethane, polyethylene or the like, allowing them to move relative to each other. . A stent 3 made of flexible and biocompatible material is attached to the distal end of the inner tube (by welding or any type of adhesive). These materials include, for example, nitinol (shape memory material), chromium cobalt and stainless steel, all with or without silicon carbide coating in addition to titanium, iridium and alloys of both.

The stent has two sections, one conical in the proximal part and the other cylindrical in the distal part. The function of the conical part is to serve as a link between the area adhered to the inner tube, with a diameter of between 1.35 and 2.3 mm and the cylindrical section with a diameter, in its released phase between 8-50 mm , preferably between 9 to 35 mm, in particular between 12-30 mm and more specifically around 25 mm, for application in the colonic region or over 18 mm, for example, for narrower regions such as the esophagus. This nexus of union facilitates the controlled opening of the stent and its subsequent encapsulation. The conical section will therefore have a variable length depending on the maximum diameter to be reached in the cylindrical section and can be calculated knowing that the angle of inclination of the conical section, once the stent is open, will be between 20 ° and 45 °. ° approximately.

The cylindrical section will have a variable length depending on the number of elastic bands to be loaded. In a preferential example, it will incorporate 6 bands and will therefore have a length of about 2 cm and a diameter between 9 and 35 cm, depending on the type of lesions to be aspirated, with the basic model presenting a diameter slightly greater than that of the endoscope. with which you want to apply (colonoscope or gastroscope). Regarding its structure, a braiding or spiraling is enough, such as that described in patent ES2369358T3. This structure may be formed, for example, by single filaments (monofilaments), with a high tensile strength of at least 100 N / mm2 and / or a modulus of elasticity of at least 500 N / mm2.

Regarding the radial force necessary to overcome the pressure exerted by the elastic bands on their surface, currently the colonic and rectal stents are considered suitable when their radial force is between 0.100 and 0.400 Kgf (0.981 and 3.924 Newton) with a variability in around 20%. In the duodenum, for example, these forces are between 0.100 and 0.350 Kgf (0.981 and 3.433 Newton), a force that allows them to acquire their cylindrical shape when released but that allows, thanks to its braiding, to contract or encapsulate again when the treatment session It is finished. One skilled in the art will recognize that there are multiple possibilities of spatial arrangements, materials and thickness of the threads or even the number of filaments of the weft that achieve this end. For example, structured monofilaments, hollow capillary monofilament, monofilament covered with a coating of one layer or more layers. In this way the monofilament wires can exhibit a structured cross section, eg a star-shaped cross section or a core clad structure cross section. Monofilament wires can have a diameter of 30 µm to 2 mm, particularly 70 µm to 500 µm.

The stent of the present invention is permanently covered, by means of an adhesive or covalent bonding, by a silicone film or film or other plastic material that maintains elasticity, being able to cover only the holes of the braid or, on the contrary, be placed as a complete coverage both by the exterior, as well as the interior of the stent structure with a thickness similar to that of the filament, that is, between 30 ^ m and 2mm. The plastic or silicone coating makes it possible to concentrate all the suction force on the distal end of the stent, that is, the area that is open and closest to the lesion, avoiding the loss of suction through the holes in the braid.

Elastic bands are placed on the stent, which in their stretched form will have a thickness of around 1mm, although they may vary in thickness depending on the maximum diameter required of them in their stretched position. The bands will be placed transverse to the longitudinal axis of the stent and will be arranged one next to the other forming parallel rows with an equal distance between them. These bands will be pre-assembled on a rope and after each one of the bands a projection made with the rope itself (knot) or by placing any material crimped on the rope and that allows the band to be approached to the end by pushing. distal free of the stent, thus being released in a controlled, one by one, by the chord mechanism controlled by a toothed wheel 5 from the proximal end of the device.

As can be seen in the cross-section of figure 2, in a particular implementation, the rope 6 is located in a channel separated from the main channel by a wall 10, made of the same material as the internal tube, whose function is to protect the rope. Enough space will remain in the main channel 10 to accommodate a polypectomy handle, diathermy accessories, or others as explained below. The rope 6 is wound on the wheel 5 arranged outside the outer tube 1b, this thread mechanism being able to be placed, both on the side wall of the inner tube in its basic shape or in a particular shape as a horizontal thread, with its matching axis of rotation. with the axis of the inner tube and in the proximal portion thereof.

Referring to Figure 1, the inner tube 1a is inserted into the outer tube 1b. Both are relatively mobile. At the distal end (closer to the lesion as will be seen later), the stent 3 is fixed in its conical part by means of welding or adhesive at point 29. In figure 1 the silicone coating has not been represented to be able to appreciate better the rest of the elements of the invention. The bands 3a are placed sequentially on the stent, with their diameters perpendicular to the main axis of the accessory.

When the inner tube 1a moves towards the distal end of the outer element 1b, the stent is no longer subjected to the pressure exerted up to that moment by the inner walls of the outer tube, so that it expands as can be seen in figure 2 .

In a preferential example, figure 1 refers to a conical termination 9 made of biodegradable material at the distal end of the device in relation to the outer tube and remaining fixed to it since the proximal end of said conical termination will have a diameter equal to the outer tube. and it will be introduced inside it thanks to a minimum compression of the material inside the tube. This termination contributes to a better displacement of the device through the working channel in those circumstances in which the endoscope is very curved within the hollow organ (large intestine, for example).

This conical termination will be expelled after the first opening of the device (figure 3, opening phase of the stent) and has a size of around 1cm in length and a diameter descending, with the size of the outer tube, with an angle between approximately 20-45 °. Regarding the material, a wide variety of biodegradable materials can be used, for example, copolymers of lactic acid and glycolic acid, PLGA (poly lactic-co-glycolic acid) among others.

In a preferential example, wedge-shaped silicone membranes 11 adhered to the stent only in its widest part and remaining above the bands, but without being adhered to them, allow the bands to be fixed when recapsulating the device. by means of the clamp mechanism exerted by the silicone membrane on one side and the stent on the other, leaving the bands on the inside and ensuring that they are not dragged by the edge of the outer tube towards the distal end of the stent and are released uncontrollably .

The inner tube is provided in its proximal third with a conduit 4 that is connected to the aspiration equipment (standard in all endoscopy equipment) in order to reduce the pressure in the area of the lesion so that it is aspirated towards the stent. Aspiration can be controlled by means of a stopcock type closure that allows the aspiration to be stopped when necessary.

The basic stages of the procedure for using the device are as follows (figure 3):

1. Introduction of the device closed by the working channel.

2. Displacement of the inner tube 1a towards the distal end. The operator must ensure that the stent is completely out of the distal end of the endoscope before beginning this step.

3. Opening the device with the bands 3a preloaded. In this stage the stent 3 acquires a diameter greater than the working channel. This stage is carried out automatically thanks to the expansion force of the stent 3.

4. Approach of the device to the lesion.

5. Placement of the open device over the target lesion.

6. Start of aspiration through duct 4 connected to the aspiration equipment.

7. Release of the elastic band 3a by means of the mechanism 5, 6.

8. Introduction of the polypectomy or diathermy loop through the inner tube for resection of the target lesion.

9. Repeat the previous process from step 4 to 8 as many times as necessary.

At the end of the treatment, or if it is desired to postpone it without releasing all the elastic bands, the stent is closed with the remaining bands, moving the inner tube towards the proximal end, the stent again acquiring a reduced diameter, equal to that of the tube Exterior. In this way the device can be removed without difficulty through the working channel.

The inner tube has at its proximal end a double membrane type valve 8 that keeps this end closed at the moment of aspiration, but at the same time allows the passage of a polypectomy handle, represented in figure 3, accessories for diathermy or others. The inner tube may also have a threaded proximal end to connect irrigation systems such as syringes or water pumps.

The form of application of the invention is represented in FIG. 4 as a preferred form. The introduction of the device through the working channel and its arrangement relative to the endoscope are observed. In this arrangement, the distance of the stent with the bands, in relation to the distal end of the endoscope is variable and can be controlled by the endoscopist or assistant who performs the intervention.

In another possible configuration, the outer tube may be provided with a thread 12 for fixing the device to the proximal end of the endoscope's working channel, thus achieving greater stability and a decrease in the possibility of accidentally removing the device when it is removed. However, in this second arrangement, the distance between the distal end of the endoscope and the stent with the preloaded bands is open, it will not be modifiable by the endoscopist or assistant. A thread can also be incorporated into the proximal end of the inner tube (1a) adapted to fix endoscopic accessories.

In view of this description and figure, the person skilled in the art will understand that the invention has been described according to some preferred embodiments thereof, but that Multiple variations can be introduced in said preferred embodiments, without exceeding the object of the invention as claimed.

Claims (9)

1. - Endoscopic accessory for ligation of injuries comprising flexible tubes, one inner (1a) and the other concentric outer (1b), movable between them and defining a distal and a proximal end and a conduit to connect to a vacuum pump at the proximal end (4), further comprising a stent (3) fixed to the distal end of the inner tube (1a), said stent having a conical section in its proximal part and another cylindrical in the distal part, the stent being covered, at the except between the openings of its weft, by a plastic or silicone material and provided with one or more elastic bands (3a) for treating injuries and a rope mechanism (5, 6) to release them. 2. Endoscopic accessory according to claim 1, characterized in that the angle of inclination of the conical section, once the stent has been opened, is between 20 ° and 45 °. Endoscopic accessory according to any of the preceding claims, characterized in that the tubes comprise Teflon, polyurethane or polyethylene. 4. Endoscopic accessory according to any of the preceding claims, characterized in that the stent comprises nitinol, chromium cobalt, stainless steel, titanium, iridium or alloys of titanium and iridium. Endoscopic accessory according to any of the preceding claims, characterized in that it comprises wedge-shaped silicone membranes 11 adhered to the stent in its widest part above the bands (3a). Endoscopic accessory according to any of the preceding claims, characterized in that it comprises a valve (8) inside the proximal end of the outer tube (1b) in a position such that it prevents the passage of air into the conduit (4). Endoscopic accessory according to any of the preceding claims, characterized in that it comprises a conical termination (9) of biodegradable material at the distal end of the outer tube. Endoscopic accessory according to any of the preceding claims, characterized in that it incorporates a thread (12) at the proximal end of the outer tube (1b) adapted to fix the accessory to an endoscope. Endoscopic accessory according to any of the preceding claims, characterized in that it incorporates a thread at the proximal end of the inner tube (1a) adapted to fix endoscopic accessories.