WO2009077047A1

WO2009077047A1 - Pouch-type orthotopic artificial bladder endoprosthesis

Info

Publication number: WO2009077047A1
Application number: PCT/EP2008/009706
Authority: WO
Inventors: Antonio Sambusetti
Original assignee: Antonio Sambusetti
Priority date: 2007-12-18
Filing date: 2008-11-17
Publication date: 2009-06-25
Also published as: ITMI20072366A1

Abstract

An orthotopic artificial bladder endoprosthesis (100) is disclosed, comprising an enclosure or bag or balloon made from a multi-layer membrane (1) comprising an intermediate base layer (2) made of a soft, elastic, synthetic material able to guarantee a correct deformation of the prosthesis, an inner coating layer (4) of highly biocompastible biomaterial able not to deteriorate upon contact with the urine and an outer coating layer (5) of highly biocompatible biomaterial able to prevent the fusing with the patient's internal tissue. The endoprosthesis further comprises a catheter or stent (80) connected to said prosthesis and adapted to be inserted into a channel formed in the patient's lumbar region to allow the outflow of the urine from the inside of the prosthesis, through the stent, out of one of the patient's flanks.

Description

POUCH-TYPE ORTHOTOPIC ARTIFICIAL BLADDER ENDOPROSTHESIS.

DESCRIPTION

The present invention refers to an orthotopic artificial bladder endoprosthesis.

As is known, when a patient's bladder is affected by severe incurable diseases which compromise the proper function thereof, the patient's very life is put at risk. Therefore, the possibility of replacing the bladder with an artificial bladder prosthesis is particularly desirable.

The PCT Patent application WO 2007/039159, in the name of the same applicant, describes an orthotopic artificial bladder endoprosthesis that is connected to the patient's ureters and urethra.

However, it must be considered that elderly patients generally have a poorly functioning urethra, due to occlusions and loss of elasticity of the urethral tissue. As a result the artificial prosthesis described in WO 2007/039159 presents some drawbacks, above all in elderly patients, who are not able to empty the artificial prosthesis easily because of a poor function of their urethra.

At present, in elderly patients, an endoprosthesis made of side-out bowel cannot be adopted, because of the state of degeneration, or rather of the poor adaptability of the intestinal tissue in an elderly patient, for the obvious reason that said tissue does not provide suitable guarantees of leak tightness and elasticity, which instead are guaranteed by the intestinal tissue of younger or relatively younger patients.

Consequently, this drawback and shortcoming is overcome in the elderly patients by making a direct connection of the ureters to two stents which exit through the patient's flanks, with application of bags along the lower limbs and with connection thereof to the stents.

Object of the present invention is to overcome the drawbacks of the prior art, by providing an orthotopic artificial bladder endoprosthesis that is particularly suitable to be implanted in elderly patients who have problems of poor urethral function. This object is achieved in accordance with the invention with the characteristics listed in the appended independent claim 1.

Advantageous embodiments of the invention are apparent from the dependent claims.

The orthotopic artificial bladder endoprosthesis according to the invention comprises a catheter or stent connected to said prosthesis and adapted to be inserted into a channel formed in the patient's lumbar region to allow the outflow of the urine from the inside of the prosthesis, through the stent, out of one of the patient's flanks.

In this manner the patient's urethra, which could show dysfunctions, particularly in the case of elderly patients, is not used. Thus the endoprosthesis according to the invention represents the only artificial prosthesis for elderly patients in whom an endoprosthesis made of side-out bowel cannot be implanted.

Further characteristics of the invention will be made clearer by the detailed description that follows, referring to a purely exemplifying and therefore non limiting embodiment thereof illustrated in the appended figures, wherein: Figure 1 is a perspective view of the orthotopic artificial bladder endoprosthesis according to the invention, connected to the patient's ureters;

Figure 2 is an enlarged cross sectional view, generically showing a portion of multi-layer sheet material for the production of the bladder prosthesis of Figure 1; Figure 3 is a sectional view, like Figure 2, showing a first embodiment of the multi-layer sheet material of Figure 2; Figures 3A and 3B are enlargements of the details enclosed in the circles A and B of Figure 3, respectively;

Figure 4 is a sectional view, like Figure 2, illustrating a second embodiment of the multilayer sheet material of Figure 2; and Figures 4A and 4B are enlargements of the details enclosed in the circles A and B of Figure 4, respectively.

With reference to Figure 1, the prosthesis according to the invention, designated as a whole with reference numeral 100, consists of an pouch-shaped enclosure or bag or balloon, made from a multi-layer membrane or sheet material 1 (Figure 2).

With reference to Figure 2, this multilayer sheet material 1 comprises an intermediate base layer 2, an inner coating layer 4 and an outer coating layer 5.

The intermediate base layer 2 consists of a synthetic material, sufficiently soft and elastic to ensure the correct deformation of the prosthesis during the physiological functioning thereof.

The inner coating layer 4 is destined to face towards the inside of the prosthesis, thus in direct contact with the urine. Therefore, said inner coating layer 4 must be made of a highly biocompatible biomaterial, able not to deteriorate on contact with the urine.

The outer coating layer 5 is destined to come into contact with the patient's internal tissues. Therefore, said outer coating layer must be made of a highly biocompatible biomaterial able not to fuse with the patient's internal tissues.

Figures 3, 3 A and 3b show a first embodiment of the invention, wherein the intermediate base layer 2 and the inner coating layer 4 are made from the materials described in the PCT patent application WO2007/039159, incorporated herein by reference. That is to say, the intermediate layer 2 consists of a multi-layer membrane 20 of soft silicone with a thickness of about 600 microns, and the inner coating layer 4 consists of a microfilm 40 of turbostratic pyrolytic carbon with a thickness of about 0.2-0.3 microns.

The silicone employed can consist, for example, of copolymers of dimethyl and metavinyl siloxane, reinforced with silica. A medical silicone is preferably used, such as, for example, that known by the trade name MED 4735™ and marketed by Nusil Technology.

The multi-layer membrane 20 is preferably obtained starting from the silicone raw material, by means of a manufacturing procedure known as dipping. The membrane 20 preferably consists of 20 layers of silicone, each with a thickness of about 30 microns.

The outer layer 5 can be made from the same material as the inner layer 4 that is with at least one microfilm 40 of pyrolytic turbostratic carbon. For example, said microfilm 40 can have a thickness of about 0.2-0.3 micron. Experimental trials have shown that the coating 40 of pyrolytic turbostratic carbon ensures better abilities not to adhere to the internal body tissues, compared with the texturised silicone used in the prior art. To further improve the ability not to adhere to the internal body tissues, as an alternative or in addition to the pyrolytic turbostratic carbon microfilm 40, the outer layer 5 can also comprise a layer of purified fatty acid 50. Among the purified fatty acids, Omega-3s are preferably used.

The layer of fatty acid 50 can be applied to the pyrolytic carbon film 40 or directly to the silicone membrane 20. In the case of the layer of fatty acid 50 being applied to the silicone membrane 20, the pyrolytic turbostratic carbon film 40 can be applied to the fatty acid 50. Obviously, a plurality of layers of pyrolytic carbon and of fatty acid, alternating with each other in all possible combinations, can be provided.

Furthermore, the inner coating 4 can also comprise one or more layers of fatty acid 50, disposed on the pyrolytic carbon or directly on the silicone.

In the event of the layer of fatty acid 50 having to be applied directly to the intermediate layer 2, the intermediate layer 2 can be made of a synthetic material able to ensure a better adhesion of the fatty acid.

As shown in Figures 4, 4A and 4B, as an alternative to the silicone, the intermediate layer 2 can be made of an ultra-light polypropylene monofilament textile 30. Said textile 30 must preferably have a weight between 30 and 120 deniers. In this case the pyrolytic carbon film 40 can be applied to the layer of fatty acid 50.

Further experimental trials have ascertained that the pyrolytic carbon film 40 can also be applied to the ultra-light polypropylene monofilament fabric 30. Therefore, in this case also, all possible combinations of pyrolytic carbon 40 and of fatty acid 50 can be adopted for coating the ultra-light polypropylene monofilament fabric 30.

Returning to Figure 1, the prosthesis 100 is provided with three holes 60, 60' and 61. The holes 60 and 60' are disposed in the upper part of the prosthesis and are larger in diameter than the patient's ureters 70, 70', so as to be able to accommodate the ureters 70, 70'.

The hole 61 , on the other hand, is disposed in a side part of the prosthesis to be able to accommodate a catheter or a stent 80 destined to face towards a patient's flank. It must be considered that the prosthesis 100 is substantially spherical, so it can be rotated 180° around a vertical axis to direct the stent 80 towards the patient's right or left flank, according to the surgeon's requirements. The stent 80 generally comprises a small tube equal or slightly larger in diameter than the ureters 70, 70', adapted to allow a regular outflow of the urine. An urethral stent, such as that known by the trade name MICROVASIVE™ , for example, is preferably used.

The holes 60, 60' and 61 are made with a special surgical instrument consisting of a handpiece or punch, with a tip with a square section 3 cm long and a final diameter between 8 and 14 charrier (Ch), to comply with the possible dimensions of the ureters 70, 70' and ofthe stent 80.

The holes 60, 60' are closed by respective portions of membrane 62, 62' similar to the multi-layer membrane which forms the bag of the prosthesis 100. The portions of membrane 62, 62' are applied to the inner surface of the prosthesis 100 from the inside, by fusion of the materials into a single layer with the bag-shaped membrane 1 of the prosthesis, and subsequent vulcanization in an oven.

The inner coating 4 is done by making a large hole in the bottom of the prosthesis 100, during the construction thereof, which then serves to turn the prosthesis inside out like a glove and to carry out the coating with the inner layer 4 on the inner surface. The hole for turning the prosthesis inside out can be the same hole 61 used for the stent 80. Once the coating has been carried out, the prosthesis 100 is turned again like a glove using the same hole 61.

Then, the hole 61 is covered with a truncated conical connector 63, made of a biocompatible material, preferably of silicone. However, the truncated conical connector 63 can be made of the same material as the prosthesis 100 or of the same material as the stent 80.

The truncated conical connector 63 is fixed to the prosthesis 100 by heat sealing or gluing, or else it can be moulded in a single piece with the prosthesis. The truncated conical connector 63 has a circular mouth 64 inside which one end of the stent 80 is press-coupled. The stent 80 is then made integral with the truncated conical connector 63 by means of suitable biocompatible fixing means, such as a biocompatible glue, heat bonding or suturing with biocompatible thread.

The truncated conical connector 63 can even be omitted. In this case, the end of the stent 80 is connected directly to the prosthesis 100, for example through hot pressing so as to form a single piece.

The whole manufacturing cycle is carried out in a controlled atmosphere that is with a controlled contamination, in a clean room. Once the manufacturing is completed, the prosthesis is placed in a double blister pack closed with a sheet of Tyvek to avoid contamination, and proceeds to an ETO (ethylene oxide) sterilization cycle.

At this point the prosthesis 100 is ready to be used in a surgical session.

The surgeon makes an abdominal incision in the patient to remove the diseased bladder and to suture the patient's urethra, which is no longer functioning.

Then, using a suitable handpiece or punch, the surgeon makes two holes 65, 65' in the two portions of membrane 62, 62', respectively, according to the diameter of the ureters 70, 70'. Since the tip of the punch is 3 cm long, there is no danger that it passes through the wall of the prosthesis on the other side. The tip of the punch is chosen according to the size of the ureters 70, 70' and the holes 65, 65' are made of the Ch measurement that the surgeon deems appropriate based on the size of the ureters 70, 70', during surgery.

The ureters 70, 70' are inserted into the respective holes 65, 65', which are elastic that is they tighten slightly around the tubes of the ureters 70, 70'. Then, the portions of membrane 62, 62' are fixed to the ureters 70, 70', respectively, by means of four suture stitches 66, 66' disposed in a square, around the respective tube of the ureters 70, 70' and passing through the membrane and the tissue of the ureters.

For example, for the suture stitches a curved, round needle must be used and the Monocryl Ethicon™ 4-0 and 5-5 thread can be used, which is produced by Johnson & Johnson and is composed of polyglecaprone that is a copolymer made by synthesis of glycolide (75%) and epsion caprolactone (25%). This thread is not coated, is monofilament and is not braided. The manufacturer indicates this thread as the most suitable for sutures in general for soft tissue and vessels, amongst which the ureters and the urethra are included. Obviously the same system with suture stitches could be used to connect the stent 80 to the connector 63 or directly to the prosthesis 100.

There are, however, other suture threads which could conveniently be adapted to the cases in question and to the requirements of the prosthesis; it is left to the surgeon's discretion to choose the one most congenial to him.

The holes for the passage of the suture stitches 66, 66' in the ureters 70, and 70' do not constitute a risk of leakage of liquid, in that the tissue reforms in a few hours. In order to avoid leakage of urine (liquid), the suture stitch holes in the portions of membrane 62, 62' are bonded and closed with one cc (one drop) of a surgical glue normally available commercially such as, for example, Glubran 2™.

The Monocryl™ thread used for the suture stitches is absorbed in about 90-120 days, but begins its downward curve of loss of tension on the 22nd day, concluding with the loss of 75% of its tensile strength on the 28th day. From the 28th day tensile strength is no longer present in the thread, but by this date the ureters 70, 70' are kept fixed by the glue and above all by the formation of the fibrotic capsule which acts as a retaining element for the ureters. It should be noted that the fibrotic or polyproteic capsule forms in about 30 days.

A simulation was done in which tubes of soft silicone, though not as soft as the ureters, were used in place of the ureters 70 and 70'. In the simulation a larger thread than the Monocryl 4-0 and 5-0 and a much larger needle, not curved like that of the Monocryl 4-0 5-0, were used for the suture.

The simulation was tested by inflating the artificial bladder prosthesis with water, and no leakage occurred from the suture holes. Considering the remarkably larger size of the thread used, the real holes in a surgical session should not have any urine leakage.

The surgeon, using a guide needle with a percutaneous tip, punctures the patient's lumbar region, so as to form a channel which leads from the prosthesis 100 to a patient's flank. This channel can be made from the inside by inserting the guide needle into the patient's abdominal incision until it exits from a patient's flank, or from the outside by inserting the guide needle into the patient's flank until it reaches the prosthesis 100.

The catheter 80 is passed into the guide channel until it exits from one of the patient's flanks. The free end of the catheter 80 that exits from the patient's flank is cut at the patient's skin and closed with a sterile plastic stopper covered with a plaster. In order to carry out the surgery, since it is a microsurgery procedure, it is necessary to use a helmet with a fibre optic transmitted light source, connected to a transformer provided with a lead for the connection to the power socket. This fibre optic transmitted light source produces a cold and white light with a beam which is perfectly round, collimated beam, not dipersed and concentrated on the site at which the suture stitches are to be applied. In addition, glasses with a binocular prismatic assembly (lens) with 2X up to 6X magnification are fitted to the helmet to enlarge the image of the surgical site in detail.

The prosthesis has a capacity of between 500 cm³ and 900 cm³ and is collapsible. That is to say, the filling and emptying mechanism of the prosthesis 1 works through the effect of the pressure differences between the air inside the prosthesis and the air outside the prosthesis.

When the urine enters the prosthesis 100 through the ureters 70, 70', a negative pressure is created inside the prosthesis 100 with respect to the outside pressure. This negative pressure prevents the urine inside the prosthesis 100 from flowing through the catheter 80, which in any case is blocked by the end stopper.

In order to empty the prosthesis 100, the patient must remove the stopper from the end of the catheter 80 and exert manually a pressure on the lower abdomen over the bladder, so as to compress the prosthesis 100 to overcome the outside pressure. In this manner, the urine contained in the prosthesis 100 flows out through the catheter 80 and the prosthesis 100 is emptied of air and is ready to receive the urine again.

In any case, even if the patient feels no urge, it is advisable to perform the prosthesis- emptying operation at least twice a day, to avoid the complete filling of the prosthesis.

Numerous changes and modifications of detail within the reach of a person skilled in the art can be made to the present exemplifying embodiments of the invention without thereby departing from the scope of the invention as set forth in the appended claims.

Claims

1. An orthotopic artificial bladder endoprosthesis (100) comprising a pouch-shaped enclosure or bag or balloon, made from a multi-layer membrane (1) comprising: - an intermediate base layer (2) made of a soft, elastic, synthetic material able to ensure a correct deformation of the prosthesis,

- an inner coating layer (4) of highly biocompatible bio-material able not to deteriorate on contact with the urine, and

- an outer coating layer (5) of highly biocompatible biomaterial able to prevent the fusing with the patient's internal tissues. characterised in that it further comprises:

- a catheter or stent (80) connected to said prosthesis and adapted to be inserted into a channel formed in the patient's lumbar region to allow the outflow of the urine from the inside of the prosthesis, through the stent (80), out of one of the patient's flanks.

2. An orthotopic endoprosthesis (100) according to claim 1, characterised in that it comprises two holes (60, 60') covered by respective portions of membrane (62, 62') of biocompatible material, adapted to be punctured to allow the connection of the patient's ureters (70, 70'), wherein said portions of membrane (62, 62') are disposed in the upper part of the prosthesis and said stent (80) is connected to a side part of the prosthesis.

3. An orthotopic endoprosthesis (100) according to claim 1 or 2, characterised in that it comprises a hole (61) within which is applied a truncated conical connector (63) of biocompatible material, having a mouth (64) adapted to receive by press-coupling one end of said stent (80) is applied.

4. An orthotopic endoprosthesis (100) according to claim 3, characterised in that said truncated conical connector (63) is heat bonded to the prosthesis around the edge of said hole (61).

5. An orthotopic endoprosthesis (100) according to claim 3, characterised in that said truncated conical connector (63) is made in a single piece with the prosthesis (100) through heat pressing.

6. An orthotopic endoprosthesis (100) according to any one of claims 3 to 5, characterised in that the end of said stent (80) is fixed to the mouth of said truncated conical connector (63) by means of heat bonding or of a biocompatible glue.

7. An orthotopic endoprosthesis (100) according to any one of claims 3 to 5, characterised in that the end of said stent (80) is fixed to the mouth of said truncated conical connector (63) by means of suture stitches with a biocompatible thread.

8. An orthotopic endoprosthesis (100) according to any one of claims 3 to 7, characterised in that said truncated conical connector (63) is made of silicone.

9. An orthotopic endoprosthesis (100) according to any one of claims 1 to 3, characterised in that the end of said stent (80) is fixed directly to said prosthesis.

10. An orthotopic endoprosthesis (100) according to any one of the preceding claims, characterised in that it further comprises a sterile plastic stopper adapted to close the free end of the stent (80).