Tissue prosthesis and a method of, and equipment for, forming a tissue prosthesis

Abstract

A tissue prosthesis 100 comprises an envelope 38 of a biologically inert, elastically deformable material capable of being expanded to conform to an interior surface of a cavity 36 formed at a site 10 in a patient's body. A filler material 60 is received in a fluent state in the envelope 38 . The filler material 60 is of the same class of material as the envelope 38 to form, when cured, together with the envelope 38 , a unified structure.

1 . A tissue prosthesis which comprises
 an envelope of a biologically inert, elastically deformable material capable of being expanded to conform to an interior surface of a cavity formed at a site in a patient's body; and   a filler material received in a fluent state in the envelope, the filler material being of the same class of material as the envelope to form, when cured, together with the envelope, a unified structure.   
   
   
       2 . The prosthesis of  claim 1  in which the envelope is of an elastomeric material capable of expanding to up to 100 times its relaxed state. 
   
   
       3 . The prosthesis of  claim 1  in which the filler material is of an elastomeric material capable of absorbing shock and withstanding compressive, tensile, bending and torsional forces. 
   
   
       4 . The prosthesis of  claim 1  in which the envelope is retained under tension after being charged with the filler material. 
   
   
       5 . The prosthesis of  claim 1  in which the envelope and/or the filler material are of an elastomeric material having a Shore Hardness in the range of between about 5 to 90 A. 
   
   
       6 . The prosthesis of  claim 1  in which the envelope and the filler material are of a silicone rubber material. 
   
   
       7 . The prosthesis of  claim 1  in which the envelope includes a neck portion, the neck portion defining a zone of weakness for facilitating separation of the envelope from a delivery device. 
   
   
       8 . The prosthesis of  claim 1  in which the envelope includes a flow control device arranged at an inlet opening to the envelope for inhibiting back flow of the filler material from the envelope. 
   
   
       9 . The prosthesis of  claim 8  which includes a flow control defining member, the flow control defining member being separate from the envelope and being arranged at the inlet opening to the envelope. 
   
   
       10 . The prosthesis of  claim 1  in which the envelope carries a marker arrangement on an exterior surface for enabling the envelope to be used to assess dimensions and a shape of the cavity and positioning of the envelope in the cavity. 
   
   
       11 . A tissue prosthesis which comprises
 an envelope of a foraminous, chemically inert material shaped to conform to an interior surface of a cavity formed at a site in a patient's body in which the envelope is to be placed; and   a filler material received in a fluent state in the envelope, the filler material being of an elastomeric material which, prior to being cured, is urged into foramens of the envelope to form an integrated structure which inhibits relative movement between the envelope and the filler material, in use, and once the filler material has cured.   
   
   
       12 . The prosthesis of  claim 11  in which the envelope is of a knitted biological or synthetic polymeric material. 
   
   
       13 . The prosthesis of  claim 11  in which the envelope is coated with a material of the same class as the filler material. 
   
   
       14 . The prosthesis of  claim 11  in which the envelope includes a flow control device arranged at an inlet opening to the envelope for inhibiting back flow of the filler material from the envelope. 
   
   
       15 . The prosthesis of  claim 14  which includes a flow control defining member, the flow control defining member being separate from the envelope and being arranged at the inlet opening to the envelope. 
   
   
       16 . A method of forming a tissue prosthesis in situ at a site in a patient's body, the method comprising:
 accessing the site in the patient's body;   if necessary, removing tissue from the site to form a cavity;   inserting an envelope of a biologically inert, elastically deformable material into the cavity;   charging a filler material, in a fluent state, into the envelope to cause the envelope to expand and conform to the shape of the cavity; and   allowing the filler material to cure, the filler material being of the same class of material as the envelope so that, when the filler material has cured, a unified prosthesis is formed.   
   
   
       17 . The method of  claim 16  which includes accessing the site by inserting an introducer through an aperture formed in tissue associated with the site and removing, if required, nuclear tissue from the site. 
   
   
       18 . The method of  claim 16  which includes, once the nuclear tissue has been removed, checking dimensions of the cavity so formed. 
   
   
       19 . The method of  claim 18  which includes using the envelope, containing suitable markers, to check the dimensions of the cavity. 
   
   
       20 . The method of  claim 16  which includes, once the envelope has been placed in position, checking the integrity of the envelope. 
   
   
       21 . The method of  claim 16  which includes evacuating an interior of the envelope to inhibit the formation or entrapment of fluid bubbles in the filler material. 
   
   
       22 . The method of  claim 16  which includes commencing filling of the envelope from a distal end of the envelope and progressively filling the envelope towards a proximal end of the envelope to inhibit the formation or entrapment of fluid bubbles in the filler material. 
   
   
       23 . The method of  claim 17  which includes, once filling of the envelope has been completed and a filler element withdrawn, occluding the aperture in the tissue of the site. 
   
   
       24 . The method of  claim 17  which includes attaching the envelope to a distal end of a tubular delivery device and everting the envelope on the distal end prior to insertion of the delivery device into the introducer for delivery of the envelope into the cavity of the site. 
   
   
       25 . The method of  16  which includes accessing the site percutaneously in a minimally invasive surgical procedure. 
   
   
       26 . The method of  claim 25  which is used to perform minimally invasive intervertebral disc nucleus replacement, the method comprising:
 forming an aperture in an annulus fibrosis of the disc percutaneously;   extracting a nucleus pulposus of the disc to form a disc cavity bounded by the annulus fibrosis of the disc and end plates of vertebrae between which the disc is located;   inserting the envelope, in a relaxed state, into the cavity through the aperture;   charging the filler material into the envelope to cause the envelope to conform to the shape of the disc cavity;   allowing the filler material to cure to form, together with the envelope, the unified prosthesis; and   occluding the aperture.   
   
   
       27 . The method of  claim 16  which includes expanding and stretching the walls of the envelope and retaining the envelope under tension after charging it with filler material. 
   
   
       28 . Equipment for forming a tissue prosthesis in situ at a site in a patient's body, the equipment comprising:
 a delivery device displaceably receivable in a lumen of an introducer, the delivery device defining a passageway;   an envelope carried at a distal end of the delivery device, the envelope being of a biologically inert, elastically deformable material capable of being expanded to conform to an interior surface of a cavity formed at the site; and   a supply of a filler material chargeable in a fluent state into the envelope through the passageway of the delivery device, the filler material being of the same class of material as the envelope to form, when cured, together with the envelope, a unified prosthesis.   
   
   
       29 . The equipment of  claim 28  which includes an aperture forming element to form an aperture into the site, the aperture forming element being receivable through the introducer for delivery to the site. 
   
   
       30 . The equipment of  claim 28  which includes a tissue removal mechanism insertable through the aperture for removing tissue, if required, to form the cavity. 
   
   
       31 . The equipment of  claim 28  in which the envelope is of an elastomeric material capable of expanding to up to 100 times its relaxed state. 
   
   
       32 . The equipment of  claim 28  in which the envelope is expanded to be stretched and retained under tension after being charged with the filler material. 
   
   
       33 . The equipment of  claim 28  in which the envelope includes a neck portion, the neck portion defining a zone of weakness for facilitating separation of the envelope from the delivery device. 
   
   
       34 . The equipment of  claim 28  in which the envelope includes a flow control device arranged at an inlet opening to the envelope for inhibiting back flow of the filler material from the envelope. 
   
   
       35 . The equipment of  claim 34  which includes a flow control defining member, the flow control defining member being separate from the envelope and being arranged at the inlet opening to the envelope. 
   
   
       36 . The equipment of  28  in which the envelope carries a marker arrangement on an exterior surface for enabling the envelope to be used to assess dimensions and a shape of the cavity and positioning of the envelope in the cavity. 
   
   
       37 . The equipment of  claim 28  in which the filler material is of an elastomeric material capable of absorbing shock and withstanding compressive, tensile, bending and torsional forces. 
   
   
       38 . The equipment of  claim 28  in which the envelope and the filler material are of an elastomeric material having a Shore Hardness in the range of about 5 to 90 A. 
   
   
       39 . The equipment of  claim 28  in which the envelope and the filler material are of a silicone rubber material. 
   
   
       40 . The equipment of  claim 28  which includes a dispenser containing the supply of filler material. 
   
   
       41 . The equipment of  claim 28  which includes a sensing arrangement configured to sense a parameter of the filler material charged into the envelope. 
   
   
       42 . The equipment of  claim 41  in which the sensing arrangement comprises a pressure sensor for sensing the pressure of filler material charged into the envelope. 
   
   
       43 . The equipment of  claim 41  in which the sensing arrangement comprises a temperature sensor for sensing the temperature of the filler material charged into the envelope. 
   
   
       44 . The equipment of  claim 41  in which the sensing arrangement is configured to sense the quantity of filler material charged into the envelope. 
   
   
       45 . The equipment of  claim 41  in which the sensing arrangement comprises a flow rate sensor for sensing the rate of flow of the filler material into the envelope. 
   
   
       46 . The equipment of  claim 41  in which the sensing arrangement is configured to sense the presence of air bubbles in the filler material charged into the envelope. 
   
   
       47 . Equipment for forming a tissue prosthesis in situ at a site in a patient's body, the equipment comprising:
 a tubular delivery device, the delivery device defining a passageway, an envelope of the prosthesis being mountable to a distal end of the delivery device to be received in a cavity at the site;   a filler member receivable in the passageway of the delivery device, the filler member being receivable with clearance in the passageway to define a gap to enable fluid to be evacuated at least from the envelope; and   a removal mechanism carried by the delivery device for enabling the envelope to be removed from the delivery device after the envelope has been charged with filler material via the filler member.   
   
   
       48 . The equipment of  claim 47  which includes an introducer and an aperture forming element to form an aperture at the site, the aperture forming element being receivable through the introducer for delivery to the site. 
   
   
       49 . The equipment of  claim 48  which includes a tissue removal mechanism insertable through the aperture for removing tissue, if required, to form the cavity. 
   
   
       50 . The equipment of  claim 48  in which the introducer and the delivery device include a retaining arrangement for retaining the delivery device with respect to the introducer. 
   
   
       51 . The equipment of  claim 47  which includes a supply of filler material attachable to a proximal end of the filler member. 
   
   
       52 . The equipment of  claim 51  in which the filler material is a mixture of a plurality of parts and in which the supply of filler material comprises a dispenser defining a plurality of chambers in each of which one part of the filler material is received prior to use. 
   
   
       53 . The equipment of  claim 51  in which the dispenser further comprises a mixer arranged intermediate an outlet of the dispenser and the proximal end of the filler member for mixing the filler material prior to charging it into the envelope. 
   
   
       54 . The equipment of  claim 47  in which a proximal end of the delivery device carries a connector for connection to an evacuating mechanism. 
   
   
       55 . The equipment of  claim 47  which includes the envelope, the envelope being of an elastomeric material capable of expanding to up to 100 times its relaxed state. 
   
   
       56 . The equipment of  claim 55  in which the envelope is expanded to be stretched and retained under tension after being charged with the filler material. 
   
   
       57 . The equipment of  claim 55  in which the envelope includes a neck portion, the neck portion defining a zone of weakness for facilitating separation of the envelope from the delivery device. 
   
   
       58 . The equipment of  claim 55  in which the envelope includes a flow control device arranged at an inlet opening to the envelope for inhibiting back flow of the filler material from the envelope. 
   
   
       59 . The equipment of  claim 58  which includes a flow control defining member, the flow control defining member being separate from the envelope and being arranged at the inlet opening to the envelope. 
   
   
       60 . The equipment of  claim 58  in which a distal end of the filler member carries an engaging member which engages the flow control device to at least partially open the flow control device and to allow the interior of the envelope to be evacuated prior to being charged with the filler material. 
   
   
       61 . The equipment of  claim 55  in which the envelope carries a marker arrangement on an exterior surface for enabling the envelope to be used to assess dimensions and a shape of the cavity and positioning of the envelope in the cavity. 
   
   
       62 . The equipment of  claim 55  in which the filler material is of an elastomeric material capable of absorbing shock and withstanding compressive, tensile, bending and torsional forces. 
   
   
       63 . The equipment of  claim 55  in which the envelope and the filler material are of an elastomeric material having a Shore Hardness in the range of about 5 to 90 A. 
   
   
       64 . The equipment of  claim 55  in which the envelope and the filler material are of a silicone rubber material. 
   
   
       65 . The equipment of  claim 47  which includes a sensing arrangement configured to sense a parameter of the filler material charged into the envelope. 
   
   
       66 . The equipment of  claim 65  in which the sensing arrangement comprises a pressure sensor for sensing the pressure of filler material charged into the envelope. 
   
   
       67 . The equipment of  claim 65  in which the sensing arrangement comprises a temperature sensor for sensing the temperature of the filler material charged into the envelope. 
   
   
       68 . The equipment of  claim 65  in which the sensing arrangement is configured to sense the quantity of filler material charged into the envelope. 
   
   
       69 . The equipment of  claim 65  in which the sensing arrangement comprises a flow rate sensor for sensing the rate of flow of the filler material into the envelope. 
   
   
       70 . The equipment of  claim 65  in which the sensing arrangement is configured to sense the presence of air bubbles in the filler material charged into the envelope. 
   
   
       71 . Equipment for forming a tissue prosthesis in situ at a site in a patient's body, the equipment comprising:
 a tubular delivery device, the delivery device defining a passageway, an envelope of the prosthesis being mountable to a distal end of the delivery device to be received in a cavity at the site;   a stiffening element arranged to project from a distal end of the delivery device with the envelope, in use, being received over the stiffening element to be supported by the stiffening element; and   a removal mechanism carried by the delivery device for enabling the envelope to be removed from the delivery device after the envelope has been charged with filler material via the filler member.   
   
   
       72 . The equipment of  claim 71  in which the stiffening element is an elongate element receivable with clearance in the passageway of the delivery device to define a gap to enable fluid to be evacuated at least from the envelope to enable fluid to be withdrawn from the envelope to collapse the envelope on to a distal end of the elongate element projecting from the distal end of the delivery device. 
   
   
       73 . The equipment of  claim 71  which includes a filler member receivable in the passageway of the delivery device after removal of the stiffening element, the filler member being receivable, after removal of the stiffening element, with clearance in the passageway to define a gap to enable fluid to be evacuated at least from the envelope. 
   
   
       74 . The equipment of  claim 71  which includes a tubular filler member receivable in the passageway of the delivery device, the filler member being receivable with clearance in the passageway to define a gap to enable fluid to be evacuated at least from the envelope and the stiffening element being a elongate element receivable through the passage of the filler member.