CA2450956C - Surgical implant - Google Patents

Abstract

A surgical implant suitable for treatment of hernias is provided. The implan t comprises a mesh having a residual maximum mass density of 50g/m2. The mesh comprises strands forming spaces and the strands comprise filaments forming pores. The spaces and pores are sized to minimise foreign body mass for implantation and to encourage integration of the implant. The mesh may be delivered using Dual Phase TechnologyTM for ease of handling, cutting and placement. The Dual Phase TechnologyTM may include encapsulation or coating with hydrogel.

Description

1 "Surgical Implaat~~

3 The present invention relates to the treatment of ~a 4 hernia such as a uterovaginal prolapse and, in particular, to a surgical implant for use in such 6 treatment and to a related surgical procedure and 7 device.

9 A hernia is basically a defect resulting in the protrusion of part of an organ through the wall of a 11 bodily cavity within which it is normally contained.
12 For example, a fairly common and well known type of 13 hernia is a defect in the lower abdominal wall 14 resulting in a sac which may contain a portion of the intestine protruding through the abdominal wall.
16 This is referred to as an inguinal hernia.
17 Similarly, a defect in the abdominal wall after 18 surgery is referred to as an incisional hernia.
19 Another type of hernia is a defect in the pelvic floor or other supporting structures resulting in a 21 portion of the uterus, bladder, bowel or other 22 surrounding tissue protruding through, e.g., the CONFIRMATION COPY

1 vaginal wall. This is usually referred to as 2 uterovaginal prolapse.

4 A common way of treating hernias is to repair the defect by sutures, whether or not the hernial sac is 6 also sutured or repaired, in order that the 7 protruding organ is contained in its normal 8 position. As the defect generally comprises a 9 weakening and attenuation leading to parting of tissues in a fascial wall, it is usually necessary 12 to apply tension to the sutures in order to close 12 the parted tissues. Thus, the fascial wall is 13 generally pinched or tensioned around the area of 14 the defect in order to close the parted tissues.
16 This treatment is generally effective, but does have 17 some inherent problems. In particular, the pinching 1~ or tensioning of tissue around the defect can lead 19 to discomfort andlor recurrence of the hernia.
Additionally, in the case of.uterovaginal prolapse, 21 such pinching or tensioning of the vaginal wall 22 almost inevitably results in anatomical distortion 23 (such as narrowing of the vaginal cavity) with 24 consequential pain and quality of life implications for the patient and relatively high recurrence 26 and/or complication rates.

23 In order to address these problems, in the case of 29 inguinal hernia repair, it has been suggested to make use of a surgical implant to overlay or close 31 the weakened and parted tissues without the need to 32 pinch or tension the surrounding tissue of the 1 fascia. Such surgical implants generally comprise 2 meshes. and are now widely used in inguinal hernia 3 repair. Meshes may be applied subcutaneously (i.e.
4 under the skin), internally ar externally of the abdominal wall and may be either absorbable or non-6 absorbable depending on the nature and severity of 7 the particular defect being treated. Meshes may be 8 applied in combination with sutures to hold the mesh 9 in place or, alternatively, with sutures that close the parted tissues as in a "non-mesh" technique.
11 Meshes are usually applied in open surgical 12 procedures, although they may sometimes be applied 13 in laparoscopic surgical procedures.

A typical mesh for an inguinal hernia repair 16 comprises woven or knitted polypropylene such as 17 Marlex~ or Prolene~.~ Such meshes have a number of 18 desirable properties that make them effective for 19 use in hernia repair. For example, they are made of materials that are suitably inert so as to be less 21 likely to cause adverse reactions when implanted in 22 the body. Furthermore, they are mechanically 23 strong, cheap, easily sterilisable and easy to work 24 with.
26 However, conventional meshes have a number of 27 inherent problems. For example, fistula or sinus 28 (i.e. abnormal passages between internal organs or 29 between an internal organ and the body surface) can develop as a result of a mesh being implanted and 31 left inside the body. More generally, the placement 32 of a foreign body subcutaneously can also lead to 1 inflammation or infection. Similarly, edge extrusion 2 (i.e. the erosion of body tissue around the edge of 3 the mesh) can occur. Nevertheless, overall, the use 4 of meshes is generally considered to be beneficial in the treatment of inCisional and inguinal hernias.

7 It has also been suggested to use meshes in the 8 treatment of uterovaginal prolapse. Meshes that 9 have been proposed for use in the repair of uterovaginal prolapse are similar to those that are 11 used for the repair of inguinal hernia and such 12 like. However, there is concern that the above 13 mentioned problems with the use of meshes are 14 greater when a mesh is placed in the vaginal wall as this tissue is generally thin only just below the 16 surface and therefore more prone to adverse 17 reactions. Furthermore, the placement of a foreign 18 body close to the rectum and urinary tract may 19 increase the risk of infection, inflammation, erosion, fistula or translocation. Thus, it is a 21 relatively widespread view that the use of meshes in 22 the treatment of vaginal prolapse is less desirable 23 than in the treatment of other hernias.

Nevertheless, as the use of meshes to treat 26 uterovaginal prolapse can avoid anatomical 27 distortion and the above mentioned problems related 28 to this, the Applicant considers there are 29 significant benefits in the use of meshes in the treatment.of uterovaginal prolapse should it be 31 possible to mitigate the problems associated with 32 mesh treatment.

1 The applicant has recognised that there are a number 2 of specific features of conventional meshes that 3 exacerbate the problems of fistula, sinus, edge 4 extrusion, infection etc., particularly when these 5 meshes are implanted in the vaginal wall. The 6 Applicant has therefore realised that it is possible 7 to provide a surgical implant that has the benefits 8 of mesh treatment, i.e. the avoidance of anatomical 9 distortion and its related problems, and also minimises the above mentioned. problems.

12 One specific problem with conventional meshes that 13 the Applicant has recognised is that they have 14 jagged or rough edges. The rough edges arise as conventional meshes are generally formed from sheets 16 of multiple woven. or intersecting fibres or strands.
17 When the meshes are cut to size in manufacture or 18 prior to fitting, the stray ends of the fibres or 19 strands are left extending from the edge of the mesh, particularly where the edge is curved. In 21 other words, the perimeter of the mesh comprises the 22 spaced ends of the fibres or strands and is not 23 smooth. It is thought that the jagged rough nature 24 of the edges of the implant increases the likelihood of extrusion of the edge of the mesh in situ.

27 Conventional meshes are generally unnecessarily 28 strong and substantial for use. in the vaginal wall 29 and of significant mass. This results in an unnecessary excess of foreign body material in the 31 vaginal wall, increasing the risks associated with 32 the placement of foreign bodies inside the human 1 body, such as the risk of infection. Likewise, the 2 bulk of such meshes can undesirably result in ,3 discomfort for the patient as the mesh can often be 4 felt when in position. This is of particular concern when a mesh is placed in sensitive vaginal 6 tissues or near to bowel or bladder.
8 A further disadvantage of the meshes presently used 9 to treat hernias relates to pore size. The pore size of meshes in use is unphysiological and does ' 11 not encourage acceptance of the implant in the body.

13 It is a aim of the present invention to overcome 14 problems associated with existing meshes used to treat hernias.

1? According to the present invention there is provided 18 a surgical implant suitable for treatment of 19 hernias, the implant comprising a mesh having a residual maximum mass density of 50g/m~.

22 Preferably the maximum mass density is less than 23 30g/m~. More preferably the maximum mass density is 24 less than 25g/m~.
26 By minimising mass density of a mesh for use in 27 treating hernias the advantages of using a mesh are 28 still apparant whereas the disadvantages are 29 lessened in that jagged and rough edges are minimised as is the risk of infection. The residual 31 mass density is the mass density of°the mesh after 32 implantation.

1 Preferably the surgical implant mesh comprises 2 strands and includes major spaces and pores.

4 The strands of the mesh may be formed by at least two filaments, the major spaces formed between the 6 strands providing the surgical implant with the 7 necessary strength, the filaments arranged such that 8 pores are formed in the strands of the mesh.

Alternatively the strands may be formed by 11 monofilaments which form loops which give rise to 12 the pores.

14 Preferably strands are spaced by wider distance than the fibres or filaments of conventional meshes used 16 in hernia repair.

18 Preferably the strands~are spaced apart to form 19 major spaces of between 1 to 10 mm.
21 More preferably the strands are spaced apart to form 22 major spaces of between 2 to 8 mm.

24 The use of mesh having strands spaced between 1 to 10 mm apart has the advantage of reducing the 26 foreign body mass that is implanted in the human 27 body. Only sufficient tensile strength to securely 28 support the defect and tissue being repaired is 29 provided by the mesh.
31 It is desirable that the mesh of the present 32 invention has a mass of between one tenth (1/l0th) 1 and one hundredth (1/100th) that of a conventional, 2 e.g. Prolene~, mesh of the same surface area. The 3 mesh of the invention therefore avoids the 4 unnecessary bulk of conventional meshes.
6 More specifically it is preferred that the mass 7 density is less than 50g/ma, more preferably less 8 than 30g/m and most preferably less than 20g/ma.
9 It is also preferred that the strands of the mesh. of the present invention are narrower than those of 11 meshes of the prior art.

13 Preferably the strands have a diameter of less than 14 600~.~.m.
16 In one embodiment the strands are arranged to form a 17 diamond net mesh.

19 In an alternative embodiment the strands are arranged to form a hexagonal net mesh.

22 The strands and filaments are preferably warp knit.

24 In. an alternative embodiment the strands are arranged to form a net mesh with suitable tensile 26 strength and elasticity. ' 28 Preferably the strands are arranged to form a net 29 mesh which has isotropic or near isotropic tensile strength and elasticity.

1 Preferably the filaments have a diameter of between 2 0.02 to 0.15 mm.

4 More preferably the filament of the mesh is of a diameter 0.08 to 0.1 mm.

7 This likewise has the advantage of reducing the 8 overall bulk of the implant, and hence the amount of 9 material retained in the human body.
11 Particular meshes which are embodiments of the 12 present invention include warp knit diamond-or 13 hexagon net diamond net meshes. Four particular 14 embodiments are set out below.
16 In two particular embodiments wherein the filaments 17 are formed from polypropylene having a diameter of 18 0.07 - 0.08mm wherein the strands are spaced to form 19 spaces of either 2mm or 5mm.
21 Alternatively, filaments are formed from polyester 22 having a diameter of 0.09mm wherein the strands are 23 spaced to form spaces of 5mm.

Alternatively, filaments are formed from polyester 26 having a diameter of 0.05 - 0.07mm wherein the 27 strands are spaced to form spaces of 2mm.

29 As the surgical implant is comprised of narrow members arranged to be spaced by relatively wide 31 gaps, major spaces, tissue may be slow to grow into 32 the mesh. It is desirable for the mesh to have 1 means for promoting tissue ingrowth. More 2 specifically, it is desirable to provide pores in 3 the strands of the mesh to aid tissue ingrowth and 4 to which tissue may more easily adhere.

6 Preferably two filaments are interwoven/knitted to 7 produce strands of the mesh comprising pores.

9 Alternatively at least three filaments are 10 interwoven/knitted to produce strands of the mesh 11 comprising pores.

13 For manufacturing reasons it is preferred that two 14 filaments are used to form the pores in the strands of the mesh which aid tissue ingrowth, however if 16 the one filament could be suitably knotted or 17 twisted to form pores of suitable dimensions it is 18 clear that this could be used to similar effect to 19 form the strands of the mesh.
21 Preferably the pores in the strands are of between 22 50 to 200~zm in diameter.

24 More preferably the pores are of between 50 to 75~1m in diameter.

27 This is important in enabling efficient fibroblast 28 throughgrowth and ordered collagen laydown in order 29 to provide optimal integration into the body. This is discussed in detail in copending Patent 31 Application No PCT/GB01/04554.

1 Rings or loops of material comprising pores of 2 between 50 to 200um may be adhered to o~r formed on 3 the strands of the mesh to provide pores.

As mentioned above, reducing the mass of the mesh 6 has distinct advantages in relation to the 7 suitability of the mesh for implantation in the 8 body, i.e. the reduction of foreign body mass and 9 improving the comfort of the patient. However, the 20 handling characteristics of such a mesh, e.g. the 11 ease with which a surgeon can manipulate and place 12 the surgical implant in its desired location in the 13 body, can be poor in some circumstances. More 14 specifically, a mesh having narrow members or strands that are widely spaced will inevitably be 16 somewhat flimsy and lacking in rigidity compared to 17 conventional meshes.

19 Ideally the implant should be formed from materials or uses technologies which provide the implant with 21 Dual Phase TechnologyTM, such that it has suitable 22 surgical handling characteristics and is also of 23 minimal mass and suited for implantation in the 24 body. The implant may be formed from a range of materials to provide it with Dual Phase 2 6 TechnologyTM .
27 The term Dual Phase TechnologyTM refers to a means 28 to provide temporary substance to the mesh.
29 Depending on the type of Dual Phase TechnologyTM
employed the benefits imported, in addition to 31 allowing minimal residual mesh mass may include 32 assisting the mesh to be handled and cut, minimising 1 the effect of rough edges, assisting placing the 2 mesh in position 'and providing tackiness to assist 3 in holding the mesh in position.on implantation, 4 thus minimising or negating the need for any additional fixation by suturing or adhesion.

7 In a preferred embodiment of the invention having 8 improved handling characteristics, the implant 9 therefore has an absorbable coating.
Preferably this coating encapsulates the mesh of the 11 surgical implant.

13 Alternatively this coating is applied to at least 14 one face of the mesh.
16 The coating, covering or layer of absorbable 17 material stiffens and adds bulk to the mesh such 18 that it is easier to handle.

As the coating, covering or layer is absorbable, it 21 is absorbed by the body after implantation and does 22 not contribute to the foreign body mass retained in 23 the body. Thus, the advantages of a surgical 24 implant having minimal mass are retained.
26 Preferably the coating, covering a layer absorbs 27 within 48 hours following implantation.

29 The coating, covering or layer may comprise any suitable soluble and biocompatible material.

1 Suitable hydrogel materials can be obtained from 2 First Water in the UK. A typical hydrogel being 3 ~ developed for use in this application is known as 4 FIRST PHASETM or PHASE 1TM .
6 The absorbable material may be a soluble hydrogel 7 such as gelatin, 9 Alternatively the absorbable material is a starch or cellulose based hydrogel.

12 In a further alternative the absorbable material is 13 an alginate.

In a further alternative the absorbable material may 16 contain hyaluronic acid.

18 The coating, covering or layer may have any 19 thickness or bulk that provides the surgical implant with suitable handling characteristics.

22 Preferably, the coating is a sheet with a thickness 23 greater than that of the mesh.

Suitable handling characteristics may also be 26 provided to the mesh by a range of other methods.
27 The surgical implant may comprise a mesh.and a 28 backing strip the backing strip releasably 29 attachable to the mesh.
31 The backing strip may be formed from a range of 32 materials including plastics.

1 The surgical implant may be releasably attachable to 2 the backing strip by adhesive.

4 The releasable attachment of a backing strip to the mesh provides a more substantial and less flexible 6 surgical implant that is more easily handled by a 7 surgeon. Following suitable placement of the 8 surgical implant the backing strip can be removed 9 from the surgical implant, the surgical implant being.retained in the body and the backing material 11 being removed by the surgeon. The surgical implant 12 can therefore benefit from reduced mass while still 13 providing characteristics required for surgical 14 handling.
16 In a further alternative the strands of the mesh of 17 the surgical implant are comprised of bicomponent 18 microfibres.

Preferably the bicomponent microfibres comprise a 21 core material and surface material.

23 The~composite or biocomponent fibres preferably 24 comprise a nonabsorbable or long lasting absorbable core and a shorter lasting absorbable surface 26 material.

28 Whereas any licensed materials amy be used, suitable 29 materials presently available include polypropylene for the core and polylactic acid or polyglycolic 31 acid for the surface materials.

1 Alternativley the bicomponent microfibres comprise 2 an material which is rapidly absorbed by the body 3 and a material which is not absorbed for a suitable 4 longer period of time.

6 Preferably the surface material is capable of being 7 absorbed by the body in a period of less than 48 8 hours.

10 Preferably the core material is capable of remaining a 11 in the body for a period of time sufficient to 12 enable tissue ingrowth.

14 The surface material of the bicomponent microfibres 15 or a portion of the composite polymers present 16 during the insertion and placement of the surgical 17 implant provides the surgical implant with 18 characteristics required for surgical handling.

Following a period of insertion in the body, the 21 surface material of the bicomponent microfibre is 22 absorbed by the body leaving behind the reduced 23 foreign mass of the core material of the strands of 24 the mesh.
26 It is preferred that the surface material of the 27 bicomponent microfibre is absorbed by the body 28 within a number of hours such that only a core 29 portion is left in the body for an extended length of time. Typically materials presently available 31 which could be used to form the microfibres are 32 absorbed by the body over a period of days or weeks.

1 The filaments of the mesh comprise a plastics or 2 synthetic material.

4 Preferably the filaments of the mesh comprise of polypropylene or polyester.

7 Alternatively the filaments of the mesh comprise an 8 absorbable material.

Tt can be appreciated that filaments which comprise 11 in part of absorbable material would allow better 12 surgical handling, but would enable the implant to 13 also have minimal mass following implantation in the 14 body.
16 Preferably the surgical implant comprises material 17 that has memory.

19 Preferably the surgical implant has memory which urges the surgical implant to adopts a flat 21 conformation.

23 Preferably the implant has a generally curved 24 perimeter, i.e. to have few or no corners or apexes, as sharp corners increase the likelihood of edge 26 erosion and infection. The specific shape will, 27 however, vary according to the use to which. the 28 implant is to be put.

Due to the variety of sizes of such defects, and of 31 the various fascia that may need repair by the 32 implant, the implant may have any suitable size, 1 Preferably the surgical implant is of width between 2 1 cm to 10 cm and of length between 1 cm to 10 cm.

4 It may be desirable to provide a variety of implants having different sizes in order that a surgeon can 6 select an implant of suitable size to treat a 7 particular patient. This allows implants to be 8 completely formed before delivery, ensuring, for 9 example, that the smooth edge is properly formed under the control of the manufacturer. The surgeon 11 would have a variety of differently sized (and/or 12 shaped) implants to hand and select the appropriate 13 implant to use after assessment of the patient..

Typically an anterior uterovaginal prolapse is 16 ellipse shaped or a truncated ellipse whereas a 17 posterior prolapse is circular or ovoid in shape.

19 Accordingly the implant shape may be any one of elliptical or tuncated ellipse, round, circular, 21 oval, ovoid or some similar shape to be used 22 depending on the hernia or polapse to be treated.

24 Different shapes are suitable for repairing different defects in fascial tissue and thus by 26 providing a surgical implant which can be cut to a 27 range of shapes a wide range of defects in fascial 28 tissue can be treated.

Preferably the mesh can be cut to any desired size.
31 The cutting may be carried out by a surgeon or nurse 32 under sterile conditions such that the surgeon need 1 not have many differently sized implants to hand, 2 but can simply cut a mesh to the desired size of the 3 implant after assessment of the patient. In other 4 words, the implant may be supplied in a large size and be capable of being cut to a smaller size, as 6 desired.

8 In this regard, whilst the surgical implant of the 9 invention is particularly useful for the repair of uterovaginal prolapse, it may be used in a variety 11 of surgical procedures including the repair of 22 hernias.

14 Preferably the surgical implant is suitable for use in the treatment of hernias including incisional and 16 inguinal hernias and/or for the treatment of 17 uterovaginal prolapse.

19 More broadly, the Applicant has therefore recognised that the implant can have any shape that conforms 21 with an anatomical surface of the human or animal 22 body that may be subject to a defect to be repaired 23 by the implant.

As discussed a disadvantage of the meshes used in 26 hernia repair is that they have jagged or rough 27 edges. Due to the wide spacing between strands of 28 the mesh described above and the small diameter of 29 the filaments, the edge problems are mitigated to an extent by the present invention.

1 To further reduce edge problems it would be 2 preferable if a mesh had a circumferential member 3 which extends, in use, along at least part of the 4 perimeter of the implant to provide a substantially smooth edge.

7 In other words, the mesh has at least one 8 circumferential member (i.e. fibre, strand. or such 9 like) that extends around at least part of its circumference.

12 Preferably at least part of the perimeter of the 13 implant is defined by the circumferential member, l5 Alternatively at least part of the perimeter of the 16 implant is defined by more than one circumferential 17 member, at the edge of the mesh.

19 The edge of the mesh, and hence the perimeter of the implant, can therefore be generally smooth and this 21 has significant advantages over conventional 22 surgical meshes. Specifically, the Applicant has 23 recognised that an implant having a smooth edge is 24 less likely to cause edge extrusion or erosion.
26 Any amount of the perimeter of the implant may be 27 defined by the circumferential member(s).

29 However, in order to maximise 'the benefits of the implant of the invention, it is preferable that at 31 least 50% of the perimeter of the implant is defined 32 by the circumferential member(s)..

1 More preferably at least 80% of the perimeter of the 2 implant is defined by the circumferential member(s).

4 Most preferably 1000 of the perimeter of the implant 5~ is defined by the circumferential member(s).

7 The majority or the whole of the perimeter of the 8 mesh being smooth minimises the risk of a rough edge 9 causing edge erosion or infection.
12 The circumferential members) may be arranged in one 12 of a~variety of ways to provide the smooth edge or 13 perimeter.

Preferably the circumferential members are arranged 16 such that they each follow the edge of a desired 17 shape of the surgical implant, the perimeter of the 18 implant formed from as few members as possible.

This simplifies the. construction of the mesh, which 21 is desirable not only for manufacture, but also 22 because simpler structures are less likely to have 23 defects which might be problematic after 24 implantation:
26 Preferably the perimeter of the mesh is defined, in 27 use, by one circumferential member.

29 Preferably the mesh has a plurality of circumferential members arranged at different radial 31 locations.

1 In order to provide an implant of given dimensions, 2 the periphery of the mesh outward of the desired 3 circumferential member is cut away such that one or 4 more selected circumferential members form the perimeter of the implant as desired.

7 More preferably, the circumferential members are 8 arranged concentrically.

A concentric arrangement of a plurailty of 11 circumferential members conveniently allows 12 maintenance of the shape of the implant for 13 different sizes of implant and provides the mesh 14 with an even structure.
16 The remainder of the structure of the mesh may take 17 a variety of forms. .

19 The circumferential members can be arranged to join with one another in order to form an integral. mesh.

22 Alternatively the mesh may additionally comprise 23 transverse members which extend across the 24 circumferential members joining the circumferential members.

27 The transverse members may extend radially from a 28 central point to the perimeter of the implant.

Alternatively, the transverse members may extend 31 toward the perimeter of the implant.

1 Preferably the transverse members are arranged to 2 provide substantially even structural strength and 3 rigidity to the implant.

It may be desirable to secure the mesh in place once 6 it has been suitably located in the patient.

8 Preferably the mesh can be sutured to strong lateral 9 tissue.
11 Alternatively, the mesh may be glued in place using 12 a biocompatible glue.

14 This is advantageous, as it is fairly quick to apply glue to the area around the surgical implant.
16 .
17 Preferably the mesh comprises at least one capsule 18 containing biocompatible glue for securing the 19 implant in place.
21 Preferably 4 capsules containing glue are provided 22 around the perimeter of the surgical implant.

24 Preferably the capsules comprise hollow thin walled spheres of around 3 to 5 mm diameter including 26 gelatin.

28 Preferably the glue is a cyanoacrylate glue.

Conventionally, open procedures have been preferred 31 for the treatment of hernias with meshes, as 32 relatively broad access is required to the site of 1 the defect to suitably implant and secure a mesh by 2 sutures or such like.

4 However, it is desirable to treat hernias, as when carrying out any surgery, with as little trauma to 6 the patient as possible. Thus, the use of minimally 7 invasive techniques has been suggested for the 8 treatment of hernias. However, such surgical 9 techniques have not been considered to be useful in the treatment of uterovaginal prolapse with a mesh, 11 as it has not been considered practical to position 12 a mesh subcutaneously in the vaginal wall due to the 13 difficulty in gaining direct access to this area.

According to another aspect of the present 16 invention, there is provided a minimally invasive 17 method of treating uterovaginal prolapse, the method 18 comprising the steps;

making an incision in the vaginal wall close to 21 the opening of the vaginal cavity and, 23 making a subcutaneous cut, through the 24 incision, over and surrounding the area of the prolapse, which cut is substantially parallel 26 to the vaginal wall; and 28 inserting a mesh according to the present 29 invention, through the incision, into the space defined by the cut.

1 Thus, a mesh or the surgical implant such as that 2 according to the invention can be inserted through a 3 small incision (e. g. around 1cm to 2 cm in length) 4 at or in the region of the periphery or opening of the vaginal cavity. An incision in this position is 6 easier for a surgeon to access than an incision 7 deeper in the vaginal, cavity, yet the Applicant has 8 realised that it is also convenient to treat vaginal 9 ~prolapse by implanting a mesh in a surgical procedure carried out entirely through such an 11 incision.

13 Preferably, the incision is at the anterior~or 14 posterior extremity of the prolapse sac of the vaginal cavity.

17 This is desirable as prolapse most often occurs in 18 the anterior or posterior vaginal wall, so 19 positioning the incision in such a location allows the most convenient access to these parts of the 21 vaginal wall.

23 The provision of suitable handling characteristics 24 for the mesh is particularly advantageous when the mesh is intended to be used in a conventional open 26 surgical procedure, as the surgeon needs to handle 27 the implant directly in order to place it in its.
28 desired location.

However, the suitable placement particularly in the 31 treatment of uterovaginal prolapse, by minimally 32 invasive techniques require the mesh to be as 1 flexible as possible and therefore to have no 2 absorbable coating or encasement.

4 A flexible, less bulky mesh.may be more easily 5 handled by tools that may be used to carry out the 6 procedure.

8 Tools that may be used to carry out this procedure 9 have a number of specific needs that need to be met 10 that are not presently met by conventional minimally 11 invasive surgical tools.

13 These specific needs can best be understood by 14 considering the steps of the surgical procedure of 15 the invention in turn.

17 The incision is made in the vaginal wall at the 18 opening of the vaginal cavity. This can be carried 19 out using a conventional implement such as a 20 scalpel. It is preferable that the incision is as 21 small as possible as this reduces trauma to the 22 patient.

24 A cut is then made in the vaginal wall over the 25 defect causing the prolapse or hernia. For example, 26 scissors or another specialised cutting tool can be 27 inserted through the incision and manipulated to 28 provide a cut over the defect. The cut is below the 29 surface of the skin and may provide a space between an upper (or outer) layer and a lower (or inner) 31 layer of the vaginal wall, or between the skin and 1 the vaginal wall, in the region of the defect, into 2 which cavity the mesh can be inserted.

4 Next, the mesh is placed in the space defined by the cut. It is preferred that the mesh of the invention 6 is supplied rolled up in order that it can be 7 inserted through a small incision and unfurled in 8 situ, i.e. in.its intended position. Thus, it may 9 be possible for the surgeon to insert the mesh through the incision by hand. However, this is 12 likely to result in the incision needing to be large 12 enough for the surgeon to insert a finger to 13 manipulate the mesh in the space. This may cause 14 unnecessary trauma to the patient and can be difficult for a surgeon to carry out.

17 According to another aspect of the present 28 invention, there is provided a surgical tool for 19 delivering a mesh subcutaneously through an incision, the tool being adapted to radially confine 21 the mesh during delivery and being operable to 22 release the mesh in its intended position.

24 Such a tool for placement of a mesh or the surgical implant of the present invention can insert and .
26 position the mesh or surgical implant in a 27 convenient and controlled manner through a small 28 incision. Furthermore, the incision through which 29 the mesh is inserted need only be as large as the diameter of the tool, or the tool when carrying the 31 mesh, which can be significantly smaller than where 1 a surgeon's finger must be able to fit through the 2 incision.

4 Preferably the tool comprises a housing and unfurling means the housing and unfurling means 6 insertable through an incision in the patient, the 7 housing and unfurling means adapted to,accommodate a 8 rolled up mesh and separable to release the mesh the 9 unfurling means capable of unfurling the rolled up mesh without any significant movement around the 11 area of the incision 13 Preferably, the tool comprises two or more parts, 14 the parts movable such that in a first position they house the mesh or surgical implant and, in a second 16 position the mesh or surgical implant is released.
17 More preferably the tool comprises two semi-circular 18 channels, an inner channel having an external 19 diameter suitable for fitting inside an outer channel.

22 The channels may be rotatable about a common axis 23 such that in a first position the open faces of the 24 channels face one another to form a closed housing and in a second position the inner channel sits 26 inside the other channel to release the mesh.

28 Alternative the tool comprises a shaft and 29 releasable securing means, the shaft adapted such that the mesh can be rolled around the shaft and 31 releasable securing means to secure the rolled mesh 32 in place.

1 In use, the tool is inserted through incision the 2 with the mesh rolled around the outside of the 3 shaft. Once the tool has been inserted,the mesh is 4 released by turning the shaft to unroll the mesh at the same time as moving the shaft acrossthe space 6 in which the mesh is being placed.

8 A needle may be used to secure the free, outer end 9 of the mesh whilst it is unfurled. The needle may be inserted through the vaginal wall to pin the mesh 21 in place. Similarly, where the mesh is released 12 from within a housing, needles may be used to ease 13 the mesh out of the open housing.

In an alternate embodiment, the tool comprises two 16 or more arms, each of which is releasably attached 17 at one end to an edge of the surgical implant. The 18 arms may be movable from a first position in which 19 they radially confine the mesh to a second position to unfurl the mesh in its intended position.

22 In one example, the arms are pivotally 23 interconnected such that they can be manipulated to 24 move the ends of the arms from the first position to the second position.

27 In another example the arms may be arranged to 28 extend radially outward from a housing to move from 29 the first position to the second position. The extendable arms may comprise wires arranged to be 31 extendable and retractable from and into the housing 32 by operation at an end of the housing.

1 In another example, the arms may be resilient or 2 sprung elements that can be released from the first 3 position and move into the second position to which 4 they are biased, i.e. to unfurl the mesh.
6 As can be appreciated, all of the above, embodiments 7 of the tool are able to unfurl the mesh without any 8 significant movement around area of the incision.
9 For example, the pivot can. be arranged to coincide with the incision, the tool rolled around an arc l1 centred at the incision or the arms operated or Z2 housing opened forward of the incision. Thus, the 13 incision can be small as no lateral movement is 14 required at the area of the incision.
l5 16 Embodiments of the present invention will now be 17 described, by way of example only, with reference to l8 the accompanying drawings, in which:
l9 Figure 1 is an illustration of a hernia;

22 Figure 2 is an illustration of the hernia of 23 figure 1 when intra-abdominal pressure is 24 raised;
26 Figure 3 is an illustration of the hernia of 27 figure 1 after repair in accordance with the 28 prior art;

Figure 4 is an illustration of the hernia of 31 figure 1 after an alternate repair in 32 accordance with the prior art;

2 Figure 5 is a schematic illustration of the 3 female human vaginal area;

5 Figure 6 is a cross-sectional view of the 6 female human vaginal area along the line A-A of 7 Figure 5;

9 Figures 7a and 7b illustrate surgical implants 10 according to the invention having a first 11 shape;
, 13 Figures 8a, 8b, 8c and 8d illustrate surgical 14 implants according to the invention having~a 15 second shape;

17 Figures 9a, 9b 9c and 9d illustrate surgical 18 implants according to the invention having a 19 third shape;

21 Figure 10 illustrates a first surgical tool 22 according to the invention in cross-section;

24 Figure 11 illustrates a second surgical tool 25 according to the invention;

27 Figure 12 illustrates a third surgical tool 28 according to the invention; and 30 Figure 13 illustrates a fourth surgical tool 31 according to the invention.

1 Referring to Figures 1 and 2, a hernia, vaginal 2 prolapse or such like occurs when a fascial wall 1 3 ruptures, forming a defect 2, i.e. a weakening or, 4 in this case, parting of the fascial wall 1. An organ 3,, contained by the fascial wall 1 is then 6 able to protrude through the defect 2. Such 7 protrusion is illustrated in Figure 2 and occurs 8 particularly when pressure within the cavity defined 9 by the fascial wall 1 is raised. For example, in the case of an inguinal hernia, when a patient 11 coughs, intra-abdominal pressure is raised and the 12 intestines may be pushed through the defect 2 in the 13 abdominal wall.

Whilst the organ 3 that may protrude through the 16 defect 2 is usually still contained by some other 17 membrane 4, the hernia, prolapse or such like is 18 inevitably painful and. liable to infection or other 19 complications. An effective and desirable treatment is therefore to close the defect 2 and contain the 21 organ 3 in its normal position.

23 Referring to Figure 3, hernias, vaginal prolapse and 24 such like are conventionally repaired by providing sutures 5 across the defect 2 to join the tissues of 26 the fascia l wall 1. In addition, it may be firstly 27 necessary to plicate (i.e. fold or reduce) the 28 membrane as this may have stretched due to 29 distention of the organ 3. Placation of the membrane corrects the stretching and helps to 31 relieve pr essure on the area of the defect 2 during 32 healing as the membrane 4 can act to contain the 1 organ 3 to some extent. Placation is generally 2 achieved by applying sutures 6 to the membrane 4.

4 Referring to Figure 4, it is also a known method of treating hernias to provide, additionally or 6 alternatively to sutures, a mesh 7 across the defect 7 4. This allows for the defect 2 to be repaired 8 without the parted tissues of the fascial wall 1 9 necessarily being brought together and for the defect to heal without the fascial wall 1 being 11 pinched or tensioned to correct the defect 2.

13 Figure 5 schematically illustrates (a sagittal view 14 of) the female human vaginal area. The vagina 8 is illustrated with its anterior portion (front) at the 16 top of the diagram and the posterior portion (rear) 17 at the bottom of the diagram. The opening of the 18 urethra, or urethral meatus, 9 is at the forward or 19 anterior end of the vagina 8. The central portion of the vagina 8 forms the vaginal cavity which 21 terminates at the cervix 10. Spaced from the 22 rearward or posterior end of the vagina 8 is the 23 anus 11. Four areas A to D of the vaginal wall 12 24 are outlined in figure 5. These areas A to D are those areas of the vaginal wall 12 in which vaginal 26 prolapse often occurs.

28 Referring to figure 6, which is a cross sectional 29 view along the line A-A in figure 5, it can be more clearly seen that the wall 12 of the vagina 8 is 31 bounded by the bladder 1.3 and urethra 14, the uterus 32 15, the small bowel 16 and rectum 17. The small 1 bowel 16 and rectum 17 are separated by the "Pouch 2 of Douglas" PoD.

4 Area A is the lower one third of the anterior vaginal wall 12 (i.e. the one third nearest the 6 entrance to the vaginal cavity) adjacent the bladder 7 13 and urethra 14. Prolapse in this area is 8 referred to as anterior or, more specifically, 9 urethracoele pro~lapse.~ Area B is the upper two thirds of the anterior vaginal wall 12. Prolapse in 11 this area is referred to as anterior or, more 12 specifically,' cystocoele prolapse. The central area 13 of the vaginal wall 12 in which the cervix 10 is 14 located is adjacent the uterus 15 and prolapse in this area is referred to as central, uterine or 16 vault prolapse. Area C is the upper one third of 17 the posterior vaginal wall 12. This area of the 18 vaginal wall 12 is adjacent the small bowel 16 and 19 prolapse in this area is referred to as posterior or entreocoele prolapse. Finally, area D is the lower 21 two thirds of the posterior vaginal wall and is 22 adjacent the rectum 17. Prolapse in this area is 23 generally referred to as posterior or rectocoele 24 prolapse.
26 Conventionally, any of the above types of hernia 27 have been treated by providing sutures in the area 28 of the prolapse. For example, the extent of the 29 defect causing the prolapse is first identified by the surgeon. Lateral sutures, i.e. sutures from one 31 side to the other of the vaginal wall 12 as seen in 32 figure 5 or right to left rather than anterior to 1 posterior, are provided across the area of the 2 defect. This joins the parted tissues of the 3 vaginal wall and repairs the defect. The organ 4 protruding through the vaginal wall is therefore contained. Disadvantages of this technique include 6 anatomical distortion of the vagina due to 7 tensioning of the wall by the sutures to repair the 8 defect .

A surgical implant for use in the repair of vaginal 11 prolapse in accordance with an embodiment of the 12 present invention comprises a mesh 20. The mesh is 13 comprised of strands 22. The strands being less 14 than 600 ~tm and approximately 150 to 600 ~.m in diameter. The strands are arranged such that they 16 form a regular network and are spaced apart from 17 each other such that for a diamond net a space of 18 between 2mm to 5mm exists between the points where 19 the strands of the mesh interact with each other (a). In a hexagonal net arrangement the space is 21 between 2mm to 5mm between opposite diagonal points 22 where the strands of the mesh interact (b).

24 It is preferable to space the strands as far as part as possible to allow blood to pass through the 26 implant and reduce the mass of the implant, while 27 providing the mesh with sufficient tensile strength 28 and elasticity to be effective. It can therefore be 29 appreciated that considerable variability in the maximum spacing between the strands can be achieved 31 depending of the material from with the strands are 1 comprised and the net pattern in which the strands 2 are arranged.

4 In the embodiment shown in figure 7a the strands are 5 arranged in a diamond net pattern 24, however any 6 pattern which provides suitable tensile strength an 7 elasticity may be used.
g 9 For example a hexagonal net pattern may be used as 10 shown in figure 7b.

12 Tdeally in order to reduce the overall mass of the 13 implant the strands 22 should have as narrow a 14 diameter as possible while still providing the mesh 15 20 with suitable tensile strength and elasticity.

17 The strands 22 of the mesh 20 are comprised of at 18 least two filaments 26 arranged to interact such 19 that pores 28 are formed between the filaments 26.
21 The pores 28 formed between the filaments 26 are 22 around.50 to 200 ~zm, such a spacing allowing 23 fibroblast through growth to occur. This fibroblast 24 through growth secures the implant 20 in place within the body. Additionally and importantly the 26 suitably sized pores allow the implant 20 to act as 27 a scaffold to encourage the lay down of new tissue.
28 The lay down of new tissue promotes the healing of 29 the hernia.
31 The filaments 26 may be formed from any 32 biocompatible material. 1n this embodiment the l filaments 26 are formed from polyester, wherein each 2 polyester filament 26 is around 0.09 mm in diameter.

4 In the embodiment shown the filaments 26 of the strands 24 are knitted together using warp knit to 6 reduce the possibility of fraying of the filaments 7 26 and strands 24.

9 Alternative suitable materials of which the filaments may be formed include polypropylene.

12 Suitable materials from which the mesh can be made:
13 provide sufficient tensile strength to support a 14 fascial wall during repair of a defect in the fascial wall causing a hernia; are sufficiently 16 inert to avoid foreign body reactions when retained 17 in the human body for long periods of time; can be 18 easily sterilised to prevent the introduction of 19 infection when the mesh is implanted in the human body; and have suitably easy handling 21 characteristics for placement in the desired 22 location in the body.

24 The fine warp knit of the filaments 26 provides a surgical implant which is flexible in handing, which 26 can be easily cut into different shapes and 27 dimensions. As the strands 24 are formed using warp 28 knit the possibility of fraying of the edge of the 29 surgical implant 20 following production or cutting of the surgical implant 20 is reduced.

1 Other methods of reducing fraying of the filaments 2 24, not arranged to form the strands using warp 3 knit, following cutting or production of the implant 4 are heat treatment, laser treatment.or the like to seal the edges of the surgical implant.

7 The mesh 20 may be supplied in any shape or size and 8 cut to the appropriate dimensions as required by the 9 surgeon.
11 It can be appreciated that cutting of the mesh will 12 produce an unfinished edge 30. Due to the sparse 13 nature of the strands that form the mesh and their 14 narrow diameter this unfinished edge does not suffer from the same problems as edges of meshes of the 16 prior art.

18 In other words the edge produced is not rough and 19 jagged such that it increases the likelihood of extrusion of the edge of the mesh in situ or the 21 chance of infection.

23 As discussed an advantage of the mesh of the present 24 invention ~is that it allows the production of a mesh suitable for use in hernia repair which allows 26 substantially less foreign material to be left into 27 the body.

29 However, the mesh being flexible and insubstantial is less suitable for allowing easy handling of the 31 mesh directly by a surgeon. Referring to figure 8a 1 and 8b the mesh described above may be treatable 2 using an ab orbable coating 32.

4 The absorbable coating 32 comprises a layer of absorbable material having a thickness greater than 6 that of the strands 22 of the mesh 20. For example, 7 the thickness of the. layer of absorbable material 8 may be around 1 to 2 mm. The strands 22 of the mesh 9 20 may be entirely embedded in the absorbable coating 32 such that the outer surface of the mesh 11 20 is covered entirely of the absorbable coating 32.

13 In effect the entire surgical implant is encased in 14 the absorbable coating as shown in figure 8b.
16 Thus, the surgical implant has no gaps or holes on 17 its surface. This has the advantage of reducing the 18 likelihood of bacteria becoming lodged on the 19 strands 22 of the mesh 20 before implantation of the mesh 20. Furthermore, the absorbable coating 32 21 makes the mesh 20 more substantial and less flexible 22 such that it is more easily handled by a surgeon.
23 This is particularly useful when it is desired to 24 place the mesh in a desired location in a conventional, open surgical procedure.

27 In an alternative embodiment shown in figure 8a the 28 absorbable coating 32 comprises a layer of 29 absorbable material applied to one face 34 of the mesh 20, such that the mesh has a first face 34 on 31 which the absorbable material has been applied and a 32 second face 36 on which the absorbable material has 1 not been applied such that the first and second 2 faces 34 and 36 each have different characteristics.

4 It can also be envisaged that the surgical implant is provided with improved surgical handling & qualities by a range of other methods. Such methods 7 including, the releasable attachment of the mesh 20 8 to a backing strip 40. This embodiment is shown in 9 figure 8c. ' 22 The backing strip may be formed from plastics 12 material and is adhered.to the surgical implant 13 using releasable adhesive.

In a similar fashion to the absorbable coating the 16 backing strip 40 causes the mesh 20 to be more 17 substantial and less flexible such that it is more 18 easily handled by a surgeon. Following the suitable 19 placement of the mesh 20 the backing strip 40 can be removed from the mesh 20, the mesh 20 being retained 21 in the body and the backing material 40 being 22 removed by the surgeon. Application of the backing 23 strip 40 to the mesh 20 means the mesh 20 benefits 24 from reduced mass but that the mesh 20 and backing strip 40 together give characteristics required for 26 surgical handling.

28 In a further embodiment the filaments of the mesh 29 may be comprised from bicomponent microfibres 50 or composite polymers 60. These technologies provide 31 the implant with dual phase technology.

1 As shown in figure 8d the bicomponent microfibres 50 2 comprise a core 52 (cutaway section shows core 3 region)and surface material 54. The surface 4 material 54 is designed such that it is absorbed by 5 the body in a matter of hours, while the core 6 material 52 remains in the body for a longer period 7 to enable tissue ingrowth.

9 Suitable bicomponent microfibres 50 include a 10 polypropelene non absorable portion and a polylactic 11 acid absorbable portion.

13 The surface material 54 is present during the 14 surgical procedure when the mesh 20 is being 15 inserted and located in the patient, and provides 16 the mesh with characteristics desirable for surgical 17 handling. Following a period of insertion in the 18 body, typically a few hours, the surface material 54 19 is absorbed into the body leaving only the core 20 material 52 of the filaments 26 in the body. The 21 core material of the filament having reduced foreign 22 mass in comparison to meshes of the prior art or the 23 mesh 20 when it also includes the surface material 24 54.
26 As shown in figure 8e the mesh of the surgical 27 implant may be formed composite polymers 60. As 28 described for the bicomponent microfibres 50, 29 composite polymers 60 provide the surgical implant 30~ with dual phase technology. A first face 62 of the 31 mesh 20 thus having particular characteristics such 32 as flexibility and elasticity, while a second face 1 64 of the mesh 20 provides the mesh 20 with 2 characteristics which improved the surgical handling 3 of the mesh 20 such as strength and robustness.
4 The cutting of the mesh described causes an unfinished edge of the mesh to be produced. This 6 unfinished mesh not being as likely to cause the 7 same problems as the rough and jagged edges of the 8 implants of the prior art, due to the fewer strands, 9 smaller diameter filaments and treatment of the mesh l0 with absorbable coating which protects the tissue 11 from the mesh during the surgical procedure when 12 damage is most likely to occur.

14 Referring to 9a, a further embodiment of the mesh 1'5 may comprise strands as discussed and more 16 specifically, perimeter strands. Typically the mesh 17 ~ is circular or the like in shape and thus this 18 perimeter strand can be generally referred to as a 19 circumferential strand 70.
21 In the example shown in figure 9a one strand runs 22 around the circumference of the oval shape of the 23 mesh 20. In another embodiment, several 24 ~ circumferential strands 70 may be present, each circumferential strand 70 may extend over one side 26 of the oval mesh 20, i.e. around half the 27 circumference of the mesh.

29 As shown in figure 9b the circumferential strands 70 are arranged concentrically and each extends around 31 the mesh 20 at a different radial location.

1 An outer circumferential strand 70 extending around 2 the perimeter of the mesh 20, and further 3 circumferential strands 72 and 74 are arranged 4 inwardly of the outer circumferential strand forming a perimeter spaced by a distance (a). The distance 6 a between adjacent circumferential members 70, 72 7 and 74, can vary and in this example is 20 mm.

9 Transverse strands 76 extend from the centre of the oval mesh 20 to points on the perimeter of the mesh 11 78. In this example, four transverse strands 76 are 12 provided across the diameter of the mesh 20, 13 dividing the mesh 18 into eight angularly equal 14 portions.
16 The mesh 20 of this embodiment may be formed from 17 materials as previously described. Depending on the 18 material chosen the mesh may be woven, knitted or 19 extruded as one piece, or individual or groups of strands can be extruded separately and joined to one 21 another.

23 Such a construction as described above provides a 24 mesh 20 with sufficient tensile strength to repair defects causing vaginal prolapse whilst having 26 minimal bulk. Similarly, such a construction 27 provides a suitably flexible yet resilient mesh for 28 handling using the surgical tools described below.
29 Referring to figures 9c and 9d, meshes 80, 82 of in the shape of the outline having angled sides 31 respectively, rather than oval, are illustrated.

1 These meshes have a similar structure to that 2 described with reference to figure 9a and b.
3 However, the mesh has a perimeter member 80 having.
4 angled sides. Further it may have transverse members arranged only to extend towards the 6 perimeter of the mesh, rather than all being across 7 the diameter of the mesh. This provides a more 8 uniform structure. More specifically, referring to 9 figure 9d the mesh has a transverse member 84 extending along its axis of symmetry, a transverse 11 member 86 bisecting the axis of symmetry, and four 12 further transverse members 88 extending from the 13 axis of symmetry to the perimeter of the mesh 90.

In addition to the pores provided by the combination 16 of filaments 26 which form the strands 22, pores can 17 be provided by rings of polypropylene positioned at 18 the intersection of the circumferential and 19 transverse members.
21 Alternatively the poxes may be formed by the spacing 22 of the transverse members, such that pores of a size 23 50-200~m suitable for enabling tissue ingrowth exist 24 between the transverse members.
26 To secure the mesh to a suitable location in the 27 body a number of methods can be used. The tackiness 28 of the absorbable coating may hold the mesh suitably 29 until it is secured by tissue ingrowth.
31 Alternatively the surgical implant can have capsules 32 100(not shown) of biocompatible.glue for securing 1 the mesh 20 in place. In this example, six capsules 2 100 comprising spheres having a diameter of 4 mm and 3 made from a rapidly absorbable material are provided 4 around the perimeter of the mesh 20. On placement in the body, the capsules 100 dissolve and release a 6 biocompatible glue contained within to secure the 7 mesh 20 in place.

9 Referring to figure 10, a tool 200 for inserting one of the meshes described (usually without an 11 absorbable coating 32) comprises two channels 202, 12 204. The channels 202, 204 are semi-circular in 13 cross-section and the channel 202 has a diameter 14 slightly smaller than the diameter of channel 204.
15. The channels are interconnected such that the 16 channel 202 can be rotated inside the channel 204.
17 In use, the mesh 20 is rolled up and placed in the 18 space formed by the channels 202,204 in a first 19 position in which the open sides of the channels face one another to form a housing or tube. After 21 insertion into the desired location, channel 204 is 22 rotated inside the channel 202 to release the mesh 23 20.

Referring to figure 11, an alternative tool 210 for 26 inserting one of the meshes described comprises an 27 elongate housing 212 around which the mesh is rolled 28 and secured. The tool 210 has means for trapping an 29 edge of the mesh 20 to secure it on the housing of the tool 212, such as a groove 214. In use, once 31 the mesh 20 has been rolled,around the housing of 3~2 the tool 210 it may be secured by a removable clip 1 or other such retaining means (not shown). After 2 insertion of the tool 210 into the desired location, 3 the mesh 20 is released and the tool 210 is rotated 4 to unfurl the mesh 20.

6 Referring to figure 12, another alternative tool 220 7 for inserting one of the meshes described above in 8 the body comprises two arms 222 pivotally 9 interconnected by a pivot 224. One end of each arm 10 226 has means for being releasably attached to the 11 mesh 20. The other end of each arm 228 is operable 12 to move the ends that may be attached to the mesh 20 13 toward or away from one another by rotation around 14 the pivot 224. V~Then the ends of the arms 226,228 to 15 which the mesh 20 can be attached are moved to a 16 position in which they are close to one another, the 17 tool 220 is substantially elongate. Furthermore, 18 the mesh 20 is radially confined by the arms. Once 19 the mesh 20 has been inserted into position, the 20 arms 226,228 can be manipulated to move the ends to 21 which the mesh 20 can be attached apart to unfurl 22 the mesh 20 in its intended position.

24 Referring to figure 13, another tool 230 for 25 inserting one of the meshes described above in its 26 desired location comprises an elongate housing 232 27 having a number of pairs of holes 234 spaced along 28 its length (in this example three pairs) at the 29 distal end of the tool 230. The housing 232 is 30 hollow and contains a number (in this case three) of 31 pairs of wires 236, made from polypropylene for 32 example, which extend along the length of the 1 housing 232 and out through the pairs of holes 234.
2 The wires 236 also protrude from the proximal end of 3 the housing such that they can be pushed and pulled 4 in and out of the housing 232. The ends of the wires 236 that protrude from the holes 234 have 6 means for releasably attaching to points near the 7 perimeter of the mesh 20.

9 In use, the wires 236 are attached to the mesh 20 l0 and retracted by pulling them back through the 11 housing 30 such that the mesh 20 is radially 12 confined close to the housing 232. Once the tool 13 230 has been inserted into the intended position, 14 the wires 236 are pushed into the housing 232 and consequently out through the holes 234 to urge the 16 mesh 20 away from the housing 232. Thus, the mesh 17 20 can be unfurled in its desired location in the 18 body.

Referring once again to figure 5 in order to repair 21 a urethracoele prolapse i.e. a defect in the area A
22 of figure 5, the surgeon first locates the defect by 23 examining the patient in the conventional manner.
24 The extent of the defect can then be ascertained and, if necessary, a suitable template used to 26 estimate the shape and dimensions of a preferred 27 surgical implant to repair the defect. A suitably 28 shaped surgical implant can then be selected.

The meshes described~above are, in this example, 31 supplied in a single size. After examination of the 32 patient and estimation of the desired dimensions of l the preferred mesh, the surgeon cuts the mesh to the 2 preferred size.

4 Where the mesh comprises a circumferential member 7.0 the cut made in the mesh is through the transverse 6 members 76 just outward of the circumferential 7 member 70 corresponding most closely with the 8 preferred size of mesh. Thus, regardless of the ~9 size to which the mesh is to be cut, a circumferential member 70 defines the perimeter of 11 the mesh, and the perimeter of the mesh is 12 substantially smooth. This desirably reduces the 13 likelihood of infection or edge erosion once the 14 mesh is inserted in the body.
16 The surgeon then attaches the mesh to or inserts the 17 mesh with one of the insertion tools described 18 herein. For example, the mesh is rolled up and 19 placed within the insertion tool 200 illustrated in figure 10, wrapped around the insertion tool 210 21 illustrated in figure 11, attached to the ends of 22 the arms 222 of the insertion tool 220 illustrated 23 in figure 12 or attached to the ends of the wires 24 236 of the insertion tool 230 illustrated in figure 13.

27 An incision 9 is then made in the vaginal wall 22 at 28 the forward most portion of the vaginal wall 12 29 adjacent the opening of the vaginal cavity. A
cutting implement (not illustrated), such as 31 scissors or a specialised cutting tool, is/are then 32 inserted through the incision 9 into the area A, 1 i.e. the lower portion of the anterior vaginal wall 2 12. Using the cutting implement, a cut is made in 3 the area A parallel with the surface of the vaginal 4 wall 12. In other words, a space is opened up in the vaginal wall 12 over the area of the defect in 6 the vaginal wall 12. The cutting implement is then 7 withdrawn and the mesh 20 is inserted in the space 8 defined by the cut.

Where the insertion tool 200 illustrated in figure 11 10 is used, the tool 200 is inserted into the area A
12 and the channel 202 rotated to a position within the 13 channel 204 to release the mesh. 20. The insertion 14 tool 200 can then be retracted and the mesh unfurls due to its inherent resilience or flat memory.
1& Should it be required to help the mesh 20 to unfurl, 17 or slightly re-position the mesh 20 defect 2, an 18 elongate tool (not shown) may be inserted through 19 the incision 9 or needles may be introduced directly through the vaginal wall 12 to manipulate the mesh 21 20. This procedure can be viewed laproscopically 22 through the incision 9 if desired.

24 V~here the insertion tool 210 illustrated in figure 11 is used, it is desirable for the insertion tool 26 210 to be inserted to one side of the space defined 27 by the cut. The mesh 20 is then released and a 28 needle inserted through the vaginal wall to hold the 29 released edge of the mesh 20 in position. The tool 210 is then rolled across the space defined by the 32 cut in an arc having a centre of rotation around the 32 incision 9. Thus, the mesh 20 is unfurled, but no 1 significant movement is required around the incision 2 9.

4 Where the insertion tool 220 illustrated in figure 12~ is used, the insertion tool 220 is simply 6 inserted through the incision 9 and opened to expand 7 the mesh 20 into its desired location. The mesh 20 8 is released from the insertion tool 220'which can 9 then be closed and withdrawn through the incision 9.
11 Finally, where the insertion tool 250 illustrated in 12 Figure 13 is used, the mesh 20 is retracted by 13 withdrawing the wires 236 through their holes 234 14 and the mesh is inserted through the incision 9.
Once the insertion tool 230 has been inserted into 16 its desired location, the wires 236 are urged 17 forward and out through the holes 234 to expand the 18 mesh in its intended position. The wires 236 can 19 then be released from the mesh 20, withdrawn into the housing 232 and the tool 230 withdrawn through 21 the incision 9.

23 Once the mesh 20 is in place, the incision may be 24 closed.
26 However, it can be desirable to secure the 20 in 27 place, rather than rely on the mesh 20 remaining in 28 its desired location of its own accord. In one 29 example, sutures are therefore be placed either laproscopically through the incision 9 or directly 31 through the vaginal wall 12 to hold the mesh 20 in 32 place. In another example, glue capsules provided 1 on the mesh 20 dissolve to secure the mesh 20 to the 2 tissue surrounding the space defined by the cut, or 3 such capsules may be punctured by needles inserted 4 directly through the vaginal wall 12.

6 The surgical implant described herein is 7 advantageous over the meshes of the prior art in 8 several ways.

10 Tn particular the mesh, of the present invention 11 includes smoother edges, the polyester material of 12 the present invention being softer than 13 polypropylene. Further, the filaments of the 14 present invention are narrower in diameter enabling 15 them to be more pliable than the strands of the 16 meshes of the prior art. This causes the edge or 17 edges of the mesh of the present invention to have 18 fewer jagged edges and thus be smoother that the 19 edges of meshes or the prior art.
21 Tn addition encasement of the mesh in an absorbable 22 coating further protects the tissue both during 23 placement and for a period of time after placement 24 of the surgical implant.
26 Dual Phase TechnologyTM such as encasement in an 27 absorbable coating or as otherwise discussed herein 28 provides the implant with good handling 29 characteristics, further it enables the implant to be more easily cut. As described above an 31 absorbable coating may protect the tissues around 32 where the implant is to be located both during 1 placement and for a period of time following 2 placement of the implant in the tissue.

4 Dual Phase TechnologyTM may also provide the implant with memory. This memory may allow the implant to 6 be more easily placed flat on the tissue. Further 7 the dual phase technology such as an absorbable 8 coating may provide the implant with mild adhesive 9 properties or tackiness which would aid both the locating and securing of the implant in the tissue.

12 The surgical implant described herein thus allows 13 tension free repair of hernias, particular vaginal 14 prolopse, with minimum pain. This allows the procedure to be performed under local anaesthetic in 16 an out patient or office setting.

18 Whilst the above embodiments of the invention have 19 been described with reference to vaginal prolapse, the mesh and surgical tools may equally be used to 21 repair any bodily hernia. Furthermore, whilst the 22 above procedure has been described in relation to a 23 urethrocoele prolapse, prolapse in other parts of 24 the vaginal wall 12 can be treated through incisions elsewhere in the vaginal wall, or other bodily 26 hernias through suitable incisions in the 27 appropriate tissue.

Claims (14)

Claims

1. A surgical implant suitable for treatment of hernia, the implant comprising a mesh comprising strands having a residual maximum mass density of 20g/m2.

2. The surgical implant as claimed in claim 1 for treatment of uterovaginal prolapse.

3. The surgical implant as claimed in claim 1 or 2, wherein the mesh comprises strands and includes major spaces and pores, the spaces existing between the strands and pores formed within the strands.

4. The surgical implant as claimed in claim 3, wherein the strands comprise a monofilament interwoven/knitted such that the strands of the mesh comprise pores.

5. The surgical implant as claimed in claim 3, wherein strands are formed from at least two filaments interwoven/knitted such that the strands of the mesh comprise pores.

6. The surgical implant as claimed in any one of claims 3 to 5, wherein the pores in the strands are of between 50 to 200 µm in diameter.

7. The surgical implant as claimed in any one of claims 1 to 6, wherein the strands are spaced apart to form major spaces of 1 to 10 mm.

8. The surgical implant as claimed in any one of claims 1 to 7, wherein the strands are arranged to form a warp knit diamond or hexagonal net mesh.

9. The surgical implant as claimed in any one of claims 1 to 8, wherein the implant has an absorbable coating, covering or layer which degrades within 48 hours.

10. The surgical implant as claimed in claim 9, wherein the coating encapsulates the mesh of the surgical implant.

11. The surgical implant as claimed in any one of claims 1 to 10 comprising a backing strip wherein the backing strip is releasably attachable to the mesh.

12. The surgical implant as claimed in any one of claims 1 to 11, wherein the strands of the mesh are comprised of bicomponent microfibres.

13. The surgical implant as claimed in any one of claims 1 to 12, wherein the surgical implant comprises material that has memory.

14. The surgical implant as claimed in any one of claims 1 to 13, wherein the mesh has at least one circumferential member which extends, in use, along at least part of the perimeter of the implant to provide a substantially smooth edge.