WO2009087306A2

WO2009087306A2 - Non-traumatic adjustable surgical ring

Info

Publication number: WO2009087306A2
Application number: PCT/FR2008/001451
Authority: WO
Inventors: Pascal Paganon
Original assignee: Compagnie Européenne D'etude Et De Recherche De Dispositifs Pour L'implantation Par Laparoscopie
Priority date: 2007-10-16
Filing date: 2008-10-16
Publication date: 2009-07-16
Also published as: WO2009087306A3; FR2922098A1

Abstract

The invention relates to a gastric ring (1) that comprises a flexible strip (2) adapted to be closed around the stomach according to a predetermined closing configuration in order to locally tighten the stomach along a perimeter having an adjustable length, wherein said strip (2) includes a hose (9) for containing a filling fluid, said hose (9) structurally having an initial conformation in which it is substantially bent on itself along a predetermined outline and has a cross section having a predetermined shape, the hose (9) also having a memory shape that allows it to recover the initial conformation thereof in the absence of stress, the flexible strip (2) defining, when in the predetermined closing configuration and in the absence of a filling fluid in the hose (9), a predetermined stomach-tightening perimeter having a length substantially not exceeding 80 mm.

Description

ATRAUMATIC ADJUSTABLE SURGICAL RING

TECHNICAL AREA

The present invention relates to the general technical field of surgical implants intended to be implanted in the body of a patient around biological organ (s) constituting a pocket or a duct, and more particularly to the gastric rings designed to treat Obesity by implantation of a flexible gastric band, intended to form a closed loop around the stomach to reduce the diameter of the opening of the stoma.

The present invention relates to a gastric band comprising a flexible band adapted to be closed around the stomach in a predetermined closure configuration, so as to locally grip the stomach at an adjustable length perimeter, said band comprising a hose for containing a filling fluid, said casing having by construction an initial conformation in which it is substantially curved on itself according to a predetermined contour and has a cross section of predetermined shape, the casing also having a shape memory allowing it to substantially recover its initial conformation in the absence of solicitation.

The present invention more particularly relates to a gastric ring, but it may also relate to a ring designed to be used to treat urinary or faecal incontinence (artificial sphincter), or a ring designed to regulate blood flow in blood vessels, this list being in no way limiting. PRIOR ART

It is already known to intervene surgically in patients with extremely severe obesity (morbid obesity), that is to say in the case of patients whose weight exceeds for example the ideal weight of at least 50 Kg, by implanting a gastric band (also called gastroplasty ring) in the body of these patients.

This widely known technique involves implanting a gastric band around the patient's stomach, in order to reduce the size of the stomach as well as the diameter of its passage (stoma).

The general structure of the gastric rings used is well known and involves a flexible band, made of elastomeric material and designed to be closed around the stomach to form a loop locally strangling the stomach. The flexible band of these known rings comprises an annular compression chamber intended to surround the stomach and thus defining a clamping perimeter of the stomach. In order to allow adjustment of the clamping perimeter, the annular compression chamber is designed to undergo diametric expansion under the effect of a liquid supply. To this end, said chamber is connected by a catheter to a device for adjusting the diameter of the chamber for injecting or removing liquid. Thanks to this feature, it is thus possible to adjust the internal diameter of the ring by injection or withdrawal of liquid, which causes a corresponding diametral expansion or retraction of the ring. The chamber of these known rings is made of a flexible and deformable material (silicone), so that the introduction of a sufficient quantity of liquid into the chamber leads to deform radially and centripetally the wall of the chamber, thereby causing a decrease in the length of the clamping perimeter of the ring. Conversely, if liquid is removed, the membrane forming the wall of the chamber undergoes a springback so that the length of the clamping perimeter of the ring is increased.

The known gastric rings of the type mentioned above generally give satisfaction, but nevertheless present a number of disadvantages.

First of all, these known rings are based on the implementation of high liquid pressure, in order to stretch the inner wall of the chamber radially and centripetalally, in order to reduce the perimeter of clamping of the ring. In other words, the rings in question are based on a principle of centripetal radial deformation of the chamber under the effect of pressurizing said chamber with a consequent liquid supply.

This operation under pressure introduces significant mechanical stresses within the ring, which are likely to damage the ring and possibly cause an accidental deflation of the chamber by liquid leakage. Such deflation is of course extremely detrimental for the patient, since it requires the replacement of the ring and therefore the realization of a new surgical operation.

In addition, the distension of the walls of the chamber under the effect of inflation of the chamber leads to folds on the inner surface of the chamber intended to be in contact with the stomach, these folds being likely to cause or promote the appearance of tissue lesions at the contact interface between the ring (and more precisely the inner wall of the chamber) and the stomach. In addition, the rings of the prior art tend, under the effect of the increase of the internal pressure in the chamber, to lose their circular nature and to become flatter as they swell, which favors the appearance of numerous folds and pinching areas on the inner face of the chamber intended to be in contact with the stomach, causes the appearance of overpressure zones (which can therefore be damaged) and finally generates a pinch effect of the stomach.

On the contrary, it is preferable, from a therapeutic point of view, for the stomach to undergo rather a balanced restriction, according to a substantially circular and smooth perimeter.

The principle of centripetal radial deformation of the chamber on which these known rings are based proves more particularly binding in terms of design, because it requires the implementation of a reinforcement on the outer wall of the ring, it is that is to say on the dorsal wall opposite to the inner wall of the chamber intended to be in contact with the stomach. This reinforcement is designed to increase the stiffness of the back wall of the ring and thus focus inward the thrust caused by the increase in pressure to promote a centripetal radial expansion of the chamber and limit the centrifugal expansion. These reinforcements are, however, generally insufficient to prevent ovalization of the ring and the appearance of wrinkles under the effect of the increase of the pressure in the chamber. Such reinforcements, which consist for example of a textile grid or a silicone excess thickness, are also generally complex to manufacture, which is likely to increase the cost of the ring.

Finally, the very principle of operation of these rings, which is based on the radial centripetal deformation of the chamber, does not allow for a universal ring capable of adapting to all situations anatomical and / or therapeutic. This is why these rings are generally offered in several sizes, the practitioner having to choose the appropriate size at the last moment, that is to say during the surgical operation when he became aware of the actual anatomical situation. The implementation of several sizes is therefore relatively restrictive since it requires that all sizes are available during the operation.

This contributes to complicating the hospital management and increasing treatment costs, while also increasing the operating risk to the extent that a mistake of choice in the size of the ring by the practitioner can never be totally ruled out.

SUMMARY OF THE INVENTION

The objects assigned to the invention therefore aim at proposing a new adjustable gastric ring making it possible to remedy the various disadvantages listed above and which, while being of particularly simple, robust and economical construction, has a particularly stable and balanced geometry as well as a Atraumatic character to be well supported by the patient.

Another object of the invention is to provide a novel gastric band particularly atraumatic and comfortable for the patient.

Another object of the invention is to propose a novel gastric ring of particularly simple and inexpensive construction.

Another object of the invention is to provide a novel gastric ring particularly simple to manufacture, while being compact, reliable and lightweight. Another object of the invention is to propose a novel gastric band that has diametral adjustment capabilities at least comparable to those of the rings of the prior art while being much less aggressive and traumatic for the stomach.

Another object of the invention is to propose a novel gastric ring capable of adapting to most of the usual anatomical situations, and which can therefore be proposed in a single size.

The objects assigned to the invention are attained by means of a gastric ring comprising a flexible band designed to be closed around the stomach in a predetermined closure configuration, so as to grip the stomach locally in a perimeter of adjustable length, said band comprising a casing for containing a filling fluid, said casing having by construction an initial conformation in which it is substantially curved on itself in a predetermined outline and has a cross section of predetermined shape, the casing having also a shape memory allowing it to substantially recover its initial conformation in the absence of bias, characterized in that the flexible strip defines, when in a predetermined configuration of closure and in the absence of filling fluid within the gut, a predetermined perimeter of squeezing the stomach whose long ur does not substantially exceed 80 mm.

SUMMARY DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention will appear better on reading the description which follows, as well as with the aid of the accompanying drawings, given purely by way of illustration and without limitation, in which: - Figure 1 illustrates, in a perspective view, a first embodiment of a gastric ring according to the invention, said ring being in the open configuration.

- Figure 2 illustrates, in a perspective view, the ring of Figure 1 in the closed configuration.

- Figure 3 illustrates, in a schematic sectional view, the ring of Figure 2 encircling the stomach.

- Figure 4 illustrates, in a partial sectional view, the ring of Figure 2.

- Figure 5 illustrates, in a view from above, a second embodiment of a gastric ring according to the invention, said ring being in the open configuration.

- Figure 6 illustrates, in a view from above, the ring of Figure 5 in the closed configuration.

- Figure 7 schematically illustrates the cross section of the hose of the ring shown in Figures 5 and 6.

BEST MODE OF REALIZING THE INVENTION

In the following description, reference will be made to a gastric band (or gastroplasty ring) designed to be implanted around the stomach to reduce the diameter of the stoma opening, or designed to be implanted around the esophagus . However, the invention is not necessarily limited to this application, and may also relate to other surgical rings, and generally the surgical rings intended to be implanted in the body of a patient around at least one organ biological hollow, constituting for example a pocket or a conduit, for modifying the passage section of said member when it is enclosed by the ring. By way of example, mention may be made of the rings used to treat urinary or faecal incontinence, or those used around blood vessels to regulate blood flow. In the case of urinary incontinence treatment, the ring will be implanted around the bladder or the urinary tract, and in the case of fecal incontinence treatment, it will be implanted around the gastrointestinal tract and especially around the anal structures. of the intestine.

Figures 1 to 7 illustrate two embodiments of a gastric ring 1 according to the invention.

The gastric band 1 is a gastric band for the surgical treatment of obesity, that is to say that the ring 1 is intended to be implanted surgically inside the body of the patient, around the stomach 3, to locally strangle the latter and thus locally reduce the section of passage of food in the stomach 3. This restriction of the stomach 3 causes a slowing of the flow of food, which allows the patient to reach quickly, and with a relatively small amount of food, a feeling of satiety.

More specifically, the ring 1 according to the embodiments illustrated in the figures is designed for the implementation of an adjustable ring gastroplasty treatment, also sometimes called annuloplasty or modular ring gastric banding, or even "AGB procedure" with reference to the English terminology "Adjustable Gastric Banding" commonly used in the field. Such a ring is intended to be positioned in the upper part of the stomach 3, preferably at the cardial part of the latter.

Preferably, the ring 1 is intended to be implanted laparoscopically, that is to say it has dimensions and properties that make it suitable to be inserted via a trocar into the body of the patient, by an operation. surgical "closed belly".

According to the invention, the gastric ring 1 comprises a flexible band 2, preferably made of an elastomeric material, such as silicone and in particular medical grade silicone. The flexible band 2 is designed to be closed around the stomach 3 according to a predetermined closure configuration (illustrated in FIGS. 2 and 6) in which it affects a closed loop shape, so as to locally grip the stomach 3 according to a perimeter P of adjustable length, thanks to technical means which will be described in more detail below.

The closure of the flexible band 2 on itself is carried out by means of complementary closure means 4, 5 formed, for example, by a male part 4 intended to be forcibly threaded into a ring 5, said male part 4 being provided with a profiled abutment 4A preventing the inadvertent reopening of the band 2 once the band closed around the stomach, but allowing this reopening provided that sufficient force is applied and directed in a direction suitable for elastically deforming the abutment 4A and / or the ring 5 and allow their disengagement. The strip 2 can thus pass, at will and reversibly, from an open configuration (illustrated in FIGS. 1 and 5) to a predetermined closure configuration (illustrated in FIGS. 2 and 6) in which the closure means 4, 5 cooperate. In order to facilitate the opening and closing operations of the ring 1, the latter is equipped with gripping tabs 6, 7, 8 to facilitate its manipulation by the surgeon, in particular when the surgeon acts laparoscopically, at least once. using mini-forceps manipulated from outside the patient's body.

In order to allow an adjustment of the length of the perimeter P in which the ring 1 locally surrounds the stomach 3, the flexible band 2 comprises a hose 9 intended to contain a filling fluid, which preferably consists of a low-viscosity liquid such as a physiological fluid or a saline solution. However, it is quite conceivable that the filling fluid of the hose 9 is constituted by a gas such as air, or conversely by a pasty or semi-pasty body, without however leaving the framework of the invention.

Advantageously, the hose 9 extends longitudinally over most of the length of the flexible band 2, and preferably extends over substantially the entire length of the clamping perimeter P formed by the band 2 when the latter is in position. in its predetermined closure configuration (Figures 2 and 6). Preferably, the casing 9 directly constitutes by itself most of the active part of the band 2 intended to act on the stomach 3.

The hose 9 is advantageously in the form of a hollow flexible tube extending between two closed ends, namely a first end 9A and a second end 9B, intended to abut one against the other in the predetermined configuration closing band 2 (Figures 2 and 6), so as to form a substantially annular casing likely to grip the stomach 3 over an angular range equal to or substantially equal to 360 °. Preferably, the hose 9 is directly in contact with the stomach 3, that is to say it defines by itself the clamping perimeter P. More specifically, the hose 9 has an internal surface 9C which is intended for to grip directly the stomach 3 and which as such defines the clamping perimeter P. The inner face 9C of the hose 9 can define a single clamping zone of the stomach, and therefore a single clamping perimeter 3, which is the case in the variant of Figures 5 to 7. But it is also quite possible that the inner face 9C defines, as in the variant of Figures 1 to 4, several clamping zones of the stomach, arranged for example in a manner staggered along the mean axis of extension XX 'of the ring 1. According to the variant of Figures 1 to 4, the hose 9 thus defines two stepped clamping zones, which delimit respectively a first and a second clamping perimeter P, P 'of the stomach 3.

The hose 9 thus delimits an empty internal space 9D forming a chamber intended to receive the filling fluid. To this end, the internal space 9D is in fluidic communication, via a connection conduit 11, with a catheter 10 which is itself connected to a housing (not shown in the figures) intended to be implanted under the skin of the patient to allow fluid to be injected into the casing 9 via the catheter 10, or on the contrary to remove fluid contained in the casing 9. Such an implantable casing, also called an implantable site or an implantable port, is well known as such and consists essentially of a sealed housing provided with a self-healing silicone puncture area, intended to be positioned under the skin of the patient and to be perforated by a hollow needle.

It is thus possible to inject or withdraw fluid, via the hollow needle, into the sealed system constituted by the combination of the implantable site, the catheter 10, the connection duct 11 and the casing 9. In the example of Figures 5 to 7, the casing 9 has substantially a rounded or oval cross section. In the example of FIGS. 1 to 4, the hose 9 has a substantially "B" shaped section delimiting two separate tubes 12, 13 which communicate freely with one another via a manifold 14 connected to the connection duct 11 and for dispensing the supply or withdrawal of fluid to or from the conduits 12, 13.

According to the invention, the casing 9 has by construction, even in the absence of fluid within it, an initial conformation (illustrated in FIGS. 1 and 5) according to which said casing 9 on the one hand is substantially curved on itself. same in a predetermined outline and on the other hand has a cross section of predetermined shape (illustrated in Figures 4 and 7). In other words, the hose 9 is preformed in a substantially curved general shape with a cross-section also preformed into a predetermined shape, said shape being able for example to be a "B" shape (variant of FIG. 4) or a shape substantially circular (variant of Figure 7) or oval.

Preferably, the predetermined contour (according to which the casing is bent on itself) is such that the casing 9 has, in its initial conformation, a form of open loop, quasi-annular, very close to the closed loop shape, annular, that it affects when the band 2 is in its closed configuration (shown in Figures 2 and 6).

Preferably, as illustrated in the figures, the hose 9 is substantially curved on itself according to a profile which is in an average plane parallel to the average plane in which fits the clamping perimeter P.

According to the particularly advantageous variants illustrated in the figures, the predetermined contour is chosen to limit to an acceptable degree the forming folds, pinches and other irregularities on the internal face 9C of the casing 9, during the passage of said casing from its initial conformation (illustrated in FIGS. 1 and 5) to the annular conformation that it adopts when the band 2 reaches its predetermined configuration closure (shown in Figures 2 and 6). "Acceptable degree" is intended to refer to irregularities so small and insignificant that they are imperceptible or almost imperceptible to the naked eye and in any case do not result in any significant adverse effect, such as pinching, adhesion or tissue necrosis. .

Preferably, and as more particularly visible in FIGS. 1 and 5, said predetermined contour is substantially oval, and is designed so that when the band 2 is in its predetermined closure configuration (illustrated in FIGS. 2 and 6), that is to say, when the ends 9A, 9B of the casing 9 abut one against the other, then the casing 9 adopts a substantially circular shape, in particular so that its internal face 9C defines a predetermined perimeter Closing P ₀ , P'o of substantially circular shape.

Advantageously, the flexible strip 2 consists of one or more parts (s) obtained (s) by molding an elastomeric material, which is preferably silicone. Thus, in the variant embodiment illustrated in FIGS. 1 to 4, the band 2 and the casing 9 are obtained by assembling:

- A back wall 2A, obtained by molding an elastomer, said back wall 2A is in the form of a flat strip which extends in a curved profile corresponding to the predetermined contour that follows the casing 9 in its conformation initial,

with an internal wall 2B, also obtained by molding an elastomer, said wall also extending in a curved profile substantially corresponding to said predetermined contour and presenting a wavy shape defining the cross section in the form of "B" mentioned above.

In the example of FIGS. 5 to 7, the strip 2 is directly constituted, as regards its active part, by the hose 9, which is formed of a single part obtained in a single molding operation. an elastomeric material, which is preferably silicone.

According to the invention, the casing 9 also has a shape memory enabling it to substantially recover, in the absence of stress, its initial conformation, and thus its predetermined curved contour and its cross section of predetermined shape. In other words, the hose 9 has a flexible and deformable character, which allows it to adopt various conformations under the effect of external stresses of deformation which it is eventually subject, the hose 9 is however able to recover, by a spontaneous elastic return phenomenon, its initial conformation as soon as said stresses of deformation disappear.

This means that when the ring 1 is at rest, without being subjected to external mechanical stresses, it has a natural tendency to systematically return to an opening configuration that corresponds to the initial conformation of the hose 9, which itself is predetermined by construction. The hose 9 thus has a dual shape memory, which is decomposed into a longitudinal shape memory allowing it to bend over itself according to said predetermined contour and a transversal shape memory allowing the cross section of the hose 9 to always come back in its predetermined form. In order to obtain in particular the transverse shape memory effect, the wall of the casing 9 delimiting the internal space 9D is advantageously made from a flexible material, with a sufficient thickness so that said wall does not present a flaccid character but on the contrary a proper mechanical strength certainly authorizing the deformation of the casing 9 but allowing however said casing 9 to always find, by elastic return, its cross section of predetermined shape.

The combination of the specific initial conformation and the shape memory making it possible to recover this initial conformation leads to the obtaining of a particularly atraumatic ring 1, since it is substantially free of irregularities on its internal face 9C and whose opening and closure are facilitated to the extent that the ring 1 has a natural tendency to be in a quasi-closed conformation particularly practical to achieve the opening or closing of the flexible band 2.

According to the invention, the flexible strip 2 defines, when in a predetermined configuration of closure (illustrated in FIGS. 2 and 6) and in the absence of filling fluid within the casing 9, a predetermined perimeter P ₀ d gripping of the stomach 3 whose predetermined length does not exceed substantially 80 mm.

Of course, in the case (illustrated in FIGS. 1 to 4) where the flexible strip 2 defines, when it is in predetermined configuration of closure and in the absence of filling fluid within the hose 9, several (in species two) predetermined perimeters P ₀ , P'o gripping of the stomach 3, then at least the length of one of these predetermined perimeters P ₀ , P'o does not exceed substantially 80 mm, and preferably the length of each predetermined perimeter Po, P'o does not exceed substantially 80 mm.

The predetermined perimeter (s) Po, P'o substantially corresponds to the multiplication of the number TT by the internal diameter D ₀ of the ring 1, said internal diameter D ₀ being defined by the top of the inner face 9C in consideration of the centripetal radial direction (see FIG. when the band 2 is in its predetermined closure configuration. The length of the predetermined perimeter P ₀ can thus be measured when the strip 2 is empty (that is to say that there is no fluid in the hose 9) and that it is in its configuration. predetermined closure (shown in Figures 2 and 6).

The choice of a value less than or equal to 80 mm for the predetermined length of the predetermined perimeter P ₀ follows from the following considerations:

According to the Applicant's experience in this field and on the basis of scientific knowledge in the field, a tight-fitting perimeter of the stomach whose length is at most 80 mm is sufficient to generate an adequate therapeutic effect in the all or almost all pathological situations. In other words, the pathological situations in which, at one time or another of the surgical treatment, it is necessary to involve a length of perimeter of grip substantially greater than 80 mm are purely hypothetical, or at least extremely rare. In the vast majority, if not all or almost all of the cases, a perimeter that has been tightened and whose length evolves in a range bounded by an upper limit substantially equal to 80 mm will make it possible to obtain a satisfactory therapeutic result.

The invention is therefore based on the idea of providing a ring which, at rest, in the absence of fluid filling, has by default a clamping perimeter sufficiently small to correspond to the minimum perimeter likely to be used in the majority of the therapeutic situations, whereas the rings of the prior art do not have, when they are at rest (deflated) such a minimum gripping perimeter and therefore require an inflation of the chamber to reach such a perimeter minimal. - The initial conformation of the hose 9 thus defines a predetermined capacity for receiving the filling fluid, and it suffices to introduce into the casing 9 a volume of filling fluid substantially corresponding to said predetermined capacity to obtain a ring with a perimeter of gripping which corresponds to the predetermined perimeter Po, the predetermined length of which is substantially less than or equal to 80 mm. On the contrary, in the prior art, it is necessary to introduce a volume of fluid greater than the capacity of the ring to centripetally deform the chamber and thus reach the minimum gripping perimeter as defined herein. -before.

Preferably, the predetermined perimeter Po (or at least one of the two predetermined perimeters P ₀ , P'o in the case of the variant of Figures 1 to 4) is of length substantially less than or equal to 70 mm, and preferably less than or equal to 60 mm. Even more preferably, said predetermined perimeter P ₀ is of length substantially less than or equal to 50 mm. The Applicant has in fact identified that excellent therapeutic results could be obtained with gripping perimeter lengths well below 80 mm, and in particular on the order of 50 mm or less.

Preferably, the length of the predetermined perimeter Po is sufficiently small to allow a substantially complete closure of the stomach 3, that is to say that the stomach 3 subject to the gripping perimeter Po is strangled to the point of prohibiting substantially the passage of food at the throttling zone, so that the food remains blocked upstream of the stomach area 3 strangled by the ring 1. In this case, it suffices to deflate the hose 9 to allow the passage of food, the section of food passage being all the more important that the hose 9 is deflated.

Preferably, the predetermined gripping perimeter Po (or at least one of the two predetermined gripping perimeters Po, PO in the case of the variant of FIGS. 1 to 4, and preferably both) extends according to a substantially circular contour, as shown in Figures 1 and 6. The implementation of a predetermined circular perimeter Po is particularly interesting because it allows a regular and balanced solicitation of the wall of the stomach 3, which reduces the risks side effects and improves patient comfort. In this case, it is particularly advantageous that said substantially circular contour defining the predetermined perimeter P ₀ has a diameter D ₀ substantially between 13 and 18 mm, and preferably substantially equal to 15 mm. This last value proves to offer an excellent compromise between therapeutic efficiency and bulkiness of the ring 1. It is also possible that the length of the predetermined perimeter P ₀ corresponds to a diameter Do whose value is chosen to generate a constriction of the largest possible stomach within the limits of what can support the tissues of the stomach.

Preferably, the cross section of the hose 9 is designed to be more or less crushed, depending on the amount of filling fluid contained in the hose 9, by the radial expansion force exerted by the stomach 3, which allows to adjust the length of the perimeter P of clamping of the ring. More specifically, the inner face 9C of the hose 9 has a sufficiently flexible character to be deformed in a centrifugal radial direction, and in particular be deformed directly by the stomach 3 itself, which has a natural tendency to expand radially (in consideration of the vertical direction materialized by the axis X-X ') to regain its initial bulk (that is prior to the implementation of gastric banding by the ring 1).

Advantageously, the cross section of the hose 9 is designed to allow the length of the clamping perimeter P to be adjusted in a range between the length of the predetermined perimeter Po and for example at least twice the length of the predetermined perimeter Po. , the amplitude of the adjustment range is not limited to twice the length of the predetermined perimeter Po, and it is for example quite possible, without departing from the scope of the invention, that this amplitude is smaller (for example corresponding to one and a half times the length of the perimeter P ₀ ) or on the contrary more extensive (for example corresponding to three times the length of the perimeter P ₀ ). In particular, this amplitude will be determined according to the specific nature of the therapeutic treatment to which the ring 1 is intended.

In other words, the shape and the flexibility of the cross section are such that the internal face 9C is capable, under the effect of the expansion force exerted by the stomach 3, to be close enough to the outer face 9E opposite to cause a doubling of the clamping perimeter. In this case, the ring 1 may for example evolve, by fluid removal, between a minimum diameter of 15 mm (corresponding to the diameter D ₀ ) and a maximum diameter of 30 mm, the minimum diameter of 15 mm being obtained by filling the hose 9 with a volume of fluid corresponding to the predetermined capacity defined by said hose 9 when it is at rest.

It is thus possible, by playing only on the flexibility of the material forming the hose 9 and especially on the amount of fluid present in the hose 9, to adjust the length of the gripping perimeter over a very wide range. extended (which goes from single to double), which allows to use a single ring 1 for all pathological situations.

Thus, the adjustment of the length of the gripping perimeter of the ring 1 essentially does not require any operation of deformation of the casing 9 by pressurizing the latter (although such deformation by setting pressure remains possible), so that reinforcement of the dorsal wall of the ring is not necessarily necessary. This is why, in the variant illustrated in FIGS. 5 to 7, the flexible band, which in this case consists of the hose 9, has an internal face 9C intended to be opposite the stomach 3 (and to the less in part in contact with the latter) and an opposite free outer face 9E (which corresponds to the dorsal wall of the ring), said outer face 9E having a mechanical strength, and in particular a stiffness, which does not substantially exceed that of the inner face 9C.

Preferably, the hose 9 is designed so that the introduction within it of a volume of filling fluid substantially corresponding to the predetermined capacity of the hose 9 does not substantially reduce the length of the gripping perimeter defined by the casing 9, said perimeter remaining substantially equal to said predetermined perimeter Po. Preferably, the addition, within the casing 9, of a volume of filling fluid substantially corresponding to the predetermined capacity of the casing 9 does not substantially cause changing the shape of the cross section of the casing 9, which remains substantially identical to the predetermined shape corresponding to the initial conformation. This technical measure is likely to minimize the appearance of folds and other surface irregularities, and to avoid possible pinching of the wall of the stomach while decreasing the stress on the material constituting the hose 9, which contributes to strengthening the strength and reliability of the ring 1. No ring of the prior art has such a characteristic, since the rings of the prior art are all based on a centripetal radial deployment of their chamber under the effect of a fluid supply. On the contrary, the ring of the invention has substantially the same shape whether it is empty or full.

It is also quite possible, without departing from the scope of the invention, to introduce into the casing 9 a volume of liquid substantially greater than the predetermined capacity of reception of the hose 9, so to generate a centripetal radial distension of the inner face 9C and thus reduce the clamping perimeter positively (and not by simple reaction of the stomach) as in the prior art.

An example of use of the operation of the gastric ring according to the variant of Figures 1 to 4 will be described in the following.

The band 2, which at rest has the configuration shown in Figure 1, is flattened, that is to say unrolled to have a substantially straight shape, to be introduced into the body of the patient through of a trocar, according to a laparoscopic technique. As soon as the band 2 is removed from the trocar, within the body of the patient, it takes over, thanks to the shape memory of the hose 9, its configuration shown in Figure 1. This allows the surgeon to facilitate the closure of the flexible band 2 around the stomach 3. This closure is performed by threading the male part 4 in the ring 5 until the stop 4A comes into blocking support against said ring 5. The band 2 is then in the predetermined configuration 2 and 3, that is to say that it forms a closed loop locally strangling the stomach 3.

The hose 9 is then filled, via the implantable site, the catheter 10, the conduit 11 and the collector 14, with a predetermined volume of fluid substantially equal to the predetermined capacity of the hose 9, defined by the initial conformation of this last. Under the effect of this volume of fluid (which is preferably constituted by a substantially incompressible liquid), the cross section of the casing 9 retains its predetermined shape, so that the stomach 3 is clamped in two clamping perimeters P, P which respectively correspond to the predetermined perimeters Po, P'o and whose length is equal to the predetermined length. For example, each perimeter P ₀ , P'o has an identical length substantially equal to 47 mm. Such a perimeter corresponds to a particularly important restriction of the stomach, and it may be conceivable to enlarge this perimeter by removing fluid, so that the volume of fluid present in the casing 9 is then less than the predetermined capacity of said casing 9, which allows the stomach, under the effect of the radial expansion force exerted by the latter, to crush outwardly the hose 9 and thus increase the length of the perimeters P, P 'd' Jaw.

Thus, the design of the ring 1 makes it possible to guarantee that:

said ring has, when it is in a high inflation state, that is to say when it receives within the hose 9 a volume of inflation fluid substantially equivalent to the predetermined capacity of the hose 9, a state smooth and atraumatic inner surface, since the filling of the casing 9 with a volume of fluid corresponding to the predetermined capacity does not cause substantially deformation of the cross section of the casing 9, which substantially retains its predetermined shape;

- Any irregularities are likely to appear on the inner face 9C when the hose 9 is deflated to adjust the perimeter of clamping, but in this case the fluid pressure in the hose 9 is low, since the volume of fluid is less than the predetermined capacity, so that the ring 1 then has a very flexible character that compensates and cancels the character potentially traumatic eventual surface irregularities likely to appear on the inner face 9C.

The invention moreover relates as such to a method of surgical treatment of obesity involving a gastric ring 1 according to the foregoing description.

The invention also relates to a surgical treatment method by local reduction of the section of at least one hollow biological organ with the aid of a surgical ring 1 comprising a flexible band 2 designed to be closed around said organ, so as to to locally grip the latter according to a perimeter of adjustable length, said band 2 comprising a hose 9 for containing a filling fluid, said hose 9 having by construction an initial conformation in which it is substantially curved on itself according to a predetermined contour and has a cross-section of predetermined shape, said initial conformation defining a predetermined capacity for receiving the filling fluid, said casing 9 also having a shape memory enabling it to find, in the absence of stress, its initial conformation, said method comprising the following steps:

a closing step, during which the flexible band 2 is closed around said member, within the body of the patient, so as to grip said organ locally,

a step of filling the casing 9 during which a volume of filling fluid is introduced into the casing 9 which does not substantially exceed said predetermined capacity, and a step of adjusting the clamping perimeter, during which fluid is removed from the casing 9 to increase the length of the clamping perimeter. BEST MODE OF REALIZING THE INVENTION

The invention finds its industrial application in the design and manufacture of implantable medical devices, in particular for the treatment of obesity.

Claims

Gastric ring (1) comprising a flexible band (2) designed to be closed around the stomach (3) in a predetermined closure configuration, so as to grip the stomach (3) locally in a perimeter (P, P ') of adjustable length, said strip (2) comprising a hose (9) intended to contain a filling fluid, said hose (9) having by construction an initial conformation according to which it is substantially curved on itself in a contour predetermined and has a cross section of predetermined shape, the casing (9) also having a shape memory allowing it to substantially recover its initial conformation in the absence of bias, characterized in that the flexible strip (2) defines, when it is in predetermined configuration of closure and in the absence of filling fluid within the casing (9), a predetermined perimeter (Po, P'o) for gripping the stomach whose length does not substantially exceed 80 mm.

2 - Ring (1) according to claim 1 characterized in that said predetermined perimeter (Po, P'o) is of length substantially less than or equal to 70 mm, and preferably substantially less than or equal to 60 mm.

3 - ring (1) according to claim 2 characterized in that said predetermined perimeter (Po, P'o) is substantially less than or equal to 50 mm.

4 - Ring (1) according to one of claims 1 to 3 characterized in that said predetermined perimeter (Po, P'o) extends in a substantially circular outline. 5 - ring (1) according to claim 4 characterized in that said substantially circular contour has a diameter (D ₀ ) substantially between 13 and 18 mm, and preferably substantially equal to 15 mm.

6 - Ring (1) according to one of claims 1 to 5 characterized in that the length of the predetermined perimeter (Po, P'o) is sufficiently small to allow a substantially complete closure of the stomach (3).

7 - Ring (1) according to one of claims 1 to 6 characterized in that the flexible strip (2) is made of an elastomeric material, such as silicone.

8 - Ring (1) according to one of claims 1 to 7 characterized in that the flexible strip (2) has an inner face (9C) intended to be opposite the stomach (3) and a free outer face opposite (9E), said outer face (9E) having a mechanical strength which does not substantially exceed that of the inner face (9C).

9 - Ring (1) according to one of claims 1 to 8 characterized in that said cross section of the hose (9) is designed to be more or less crushed, depending on the amount of filling fluid that contains the hose (9).

10-Ring (1) according to claim 9 characterized in that the cross section of the hose (9) is designed to allow to adjust the length of the clamping perimeter (P, P ') in a range between the length of the perimeter predetermined (Po, P'o) and at least twice the length of the predetermined perimeter (Po, P'o) - -Antenle (1) according to one of claims 1 to 10 characterized in that said initial conformation defines a predetermined capacity for receiving the filling fluid, the hose (9) being designed so that the introduction into it of a volume of filling fluid substantially corresponding to said predetermined capacity does not substantially reduce the length of the gripping perimeter (P, P ') defined by the hose (9), said perimeter (P, P') remaining substantially equal to said predetermined perimeter (Po, PO) -