A BARRIER FOR TISSUE SEPARATION

Abstract: The present invention relates to a barrier and a method for tissue separation. The barrier comprises a biodegradable membrane and a biodegradable sealing agent to seal said membrane against an injured tissue area.

Description: A BARRIER FOR TISSUE SEPARATION The present invention relates to a barrier for tissue separation. More precisely, the invention relates to a barrier comprising a biologically degradable membrane. A large and general problem within medicine is that injured or defective tissue heals incorrectly in spite of implemented surgical corrective measures. The most common case is about post- surgical growing together of organs or organ parts which in the normal case shall be able to move freely in relation to each other. Another usual example is overgrowth of an injured area which is the case, for example, in association with excessive scar formation in the skin, adherences in about every organ part and strictures in hollow organs like intestine, uterus and ureter. Many cases of incorrect healing depend on influence from foreign cells in excess. An example of this is fibroblasts which in excess form far too much collagen. Some known ways to try to solve these problems are firstly to perform the surgical reparair as little injuring as possible and secondly to insert barriers between the relevant organ parts. These barriers have included the patient's own fat as well as collagen materials or surgical web. It is also known to use biologically degradable membranes between the organ parts but it has been difficult to arrange these tightly against the tissue and thereby protect the same from the environmental influences. In prior art, sutures and screws have been used to attach biologically degradable membranes against injured tissue, see, for example, EP A2 0349 505. However, these solutions are complicated and unreliable because the attachement means used do not function satifactorily. Either they are complicated and time consuming or unreliable because they are detached from their attachment sites. The present invention solves the problem with incorrect healing of the injured or defective tissue in that the injured or defective tissue is blocked from surrounding healthy tissue, whereby healing without complications is obtained. This is obtained in that the injured area is temporarily isolated from the influence of surrounding tissue and cells. According to the present invention the injured tissue section is isolated by a barrier. The barrier comprises a biologically degradable membrane and a biologically degradable sealing agent, the sealing agent being used to seal the membrane against an injured tissue area. The membrane should be of a non-porous type, ie. one that does not permit cells to pass therethrough. In principle any biologically degradable material can be used for the membrane and sealing agent, respectively. Examples of suitable biologically degradable materials are polyglycolide and co-polymers thereof, polylactides and co-polymers thereof, poly- β-hydroxybut rate and co-polymerisates thereof, poly-p-dioxanon, poly-δ-valerolactone, poly-6-caprolactone, methyl-metacrylate-N- vinyl pyrrolidine co-polymers, polyesther amides, polyesters of oxalic acid, polydihydropyranes, polyalcyl-2-cyanoacrylates, polyurethanes, polyvinylalcohol, polypeptides, poly-β-maleicacid and poly-β-alcanoic acids. The invention will now be described below in more detail in association with some examples of how to use the invention. Example 1: Prevention of growing together of meninxs After surgery in the brain it is desirable to seal the meninx while the same is allowed to heal spontaneously. According to the invention a rectangular piece of lactide membrane is cut in a shape so that it covers the opening caused by the surgery. A thin strip of polylactide (40%) dissolved in acetone is applied around the opening. The membrane is laid in position and is gently pressed to adhere against the meninx. After a short time of aering the outer portions of the wound are sealed. Example 2: Prevention of growing together of muscle groups Thigh muscles can after exterior violence be hurt so seriously that an incorrect healing arises with formation of fibrous connective tissue and growing together of adjacent muscle groups. Such conditions are usually not improvable with movement therapy and massage. After surgical removal of the incorrect healing with accompanying control of the bleeding, a thin glue strand (40% polylactide in acetone) is applied around the injury on the connective tissue capsule, whereafter a suitably dimensioned membrane piece is arranged over the deficiency and against the glue. Example 3: Prevention of growing together between nerve and bone On peripher nerves, for example nervus saphenous in the tibia area, cysts can be stimulated to develop. In connection with a surgical removal of the cyst a protective dressing is arranged about the nerve in the following way. A piece of lactide membrane is cut so that it is possible to wind one and a half turns around the nerve and so that its length is exceeding that of the cyst with 10 mm. A thin glue strand (40% polylactide in acetone) is arranged partly on the peripher ends of the nerve and partly on the outer edge of the longitudinal joint where the lactide membrane is to be joined together. After applying of the membrane, the glue portions are pressed together and are allowed to dry during 10-15 minutes, whereafter the incision site is sealed. The healing occurs with the retained nerve function and without pressure pain or other complication signs. Example 4: Prevention of growing together of bones and granulation tissue In this example reference is made to the accompanying drawing. Figure 1 shows a tooth 1 being fastened in bone 2. Beneath the crown of the tooth there is gingiva or epithelium 3, covering the bone 2. A bone recess had developped in the branching site 4 of a molar tooth 1 leading to loss of the attachment. Previous clearance of the area did not lead to any improvment of the condition. The gingiva 3 was freed from the deficiency, tartar depositions were removed and the worst granulation tissue was removed. A polylactide membrane 5 was cut into a shape so that it substantially followed the tooth profile over the deficiency and in the periphery reached to the bone edge. The part 6 of the tooth being on the same height as the gingiva 3 was provided with a glue strand (about 40% lactide in acetone). The membrane 5 was put adjacent the tooth 1 so that the glue connected it with the tooth. The outer edges of the membrane were put under the backfolded gingiva 3 but over the bone edge. The mucous membrane was folded back and fastened with a couple of sutures over the deficiency. The epithelia is now allowed to grow without influence from the environment in the mouth cavity. Within about 6 weeks the injury is healed and an apparent improvement of the attachment is obtained. After about three months the bone deficiency is beginning to fill out. In the above examples lactide has been used both for the membrane and the sealing agent, above denoted "glue". It is ,however, understood that also other biologically degradable materials can be used. The sealing agent should be soluble in a physiologically acceptable solvent and liquid at the application of the membrane, and thereafter the sealing agent converts to a solid condition. The rate with which the membrane is degraded can be varied in that the concentration of lactide or any other degradable polymer in the membrane is varied. Preferably membranes and sealing agents of the same kind are chosen, to obtain a common biological degradation rate. By the barrier according to the invention, healing of injured and/or defective tissue is enabled in a way that was previously not possible.

Claims: CLAIMS 1. A barrier for tissue separation comprising a biodegradable membrane, wherein it also comprises a biodegradable sealing agent to seal said membrane against an injured tissue area. 2. A barrier according to claim 1, wherein said sealing agent and said membrane comprise material selected from the group consisting of polyglycolide and co-polymers thereof, polylactides and co-polymers thereof, poly-β-hydroxybutyrate and co-polymeri- sates thereof, poly-p-dioxanon, poly-δ-valerolactone, poly-6- caprolactone, methyl-metacrylate-N-vinyl pyrrolidine co-polymers, polyesther amides, polyesters of oxalic acid, polydihydropyranes, polyalcyl-2-cyanoacrylates, polyurethanes, polyvinylalcohol, polypeptides, poly-β-maleic acid and poly-β-alcanoic acids. 3. A barrier according to claim 1 or 2, wherein said sealing agent is dissolved in a solvent. 4. A barrier according to claim 1 or 2, wherein said sealing agent is heated before sealing said membrane. 5. A barrier according to one ore more of the claims 1-4, wherein said sealing agent and said membrane comprise the same material. 6. A barrier according to claim 5, wherein said sealing agent and said membrane comprise poylactide. 7. A method to treat injured or defective tissue to avoid that it heals incorrectly, comprising attaching of a biologically degradable membrane against said injured tissue by a biologically degradable sealing agent. 8. A method according to claim 7, comprising dissolving said sealing agent in a solvent. 9. A method according to claim 7, comprising heating of said sealing agent before attaching said membrane. 10. Use of a barrier comprising a biologically degradable membrane and a biodegradable sealing agent for tissue separation. _ _ AMENDED CLAIMS [received by the International Bureau on 4 December 1992 (04.12.92); original claim 10 deleted; remaining claims unchanged (2 pages)] 1. A barrier for tissue separation comprising a biodegradable membrane, wherein it also comprises a biodegradable sealing agent to seal said membrane against an injured tissue area. 2. A barrier according to claim 1, wherein said sealing agent and said membrane comprise material selected from the group consisting of polyglycolide and co-polymers thereof, polylactides and co-polymers thereof, poly-β-hydroxybutyrate and co-polymeri- sates thereof, poly-p-dioxanon, poly-δ-valerolactone, poly-6- caprolactone, methyl-metacrylate-N-vinyl pyrrolidine co-polymers, polyesther amides, polyesters of oxalic acid, polydihydropyranes, polyalcyl-2-cyanoacrylates, polyurethanes, polyvinylalcohol, polypeptides, poly-β-maleic acid and poly-β-alcanoic acids. 3. A barrier according to claim 1 or 2, wherein said sealing agent is dissolved in a solvent. 4. A barrier according to claim 1 or 2, wherein said sealing agent is heated before sealing said membrane. 5. A barrier according to one ore more of the claims 1-4, wherein said sealing agent and said membrane comprise the same material. 6. A barrier according to claim 5, wherein said sealing agent and said membrane comprise poylactide. 7. A method to treat injured or defective tissue to avoid that it heals incorrectly, comprising attaching of a biologically degradable membrane against said injured tissue by a biologically degradable sealing agen . 8. A method according to claim 7, comprising dissolving said sealing agent in a solvent. 9. A method according to claim 7, comprising heating of said sealing agent before attaching said membrane.

Inventors: AAGERUP BENGT, AAGERUP, BENGT
Applicants: MEDINVENT SA, MEDINVENT
Application year: 1992
Main classification: A61L27
IPC codes: A61L31