An implantable prosthesis for repairing soft tissue or muscle wall defects, comprising: a first biocompatible structure in the form of a first layer; a reinforcement member positioned adjacent a bottom side of the first biocompatible structure; a mesh structure configured to promote tissue ingrowth, in the form of a second layer positioned adjacent a bottom surface of the reinforcement member; a second biocompatible structure in the form of a third layer positioned adjacent a bottom surface of the mesh structure; and an anti-adhesion barrier in the form of a fourth layer positioned on a bottom surface of the second biocompatible structure, wherein the anti-adhesion barrier is a bioresorbable layer for reducing adhesion of underlying tissue and organ surfaces to the implantable prosthesis, wherein: the reinforcement member has a stiffness greater than the stiffness of the first and second biocompatible structures (110, 140); the first biocompatible structure, the reinforcement member, the mesh structure, the second biocompatible structure, and the anti-adhesion barrier are aligned and secured together; and the reinforcement member includes a central hub and a plurality of spokes extending radially from the central hub, characterised in that the implantable prosthesis is substantially umbrella-shaped, the spokes being formed from flexible material configured to allow the implantable prosthesis to be collapsed to a frustoconical or shuttlecock shape for insertion into an aperture and then expanded to conform to the shape of an inner wall of a body cavity. a first biocompatible structure in the form of a first layer; a reinforcement member positioned adjacent a bottom side of the first biocompatible structure; a mesh structure configured to promote tissue ingrowth, in the form of a second layer positioned adjacent a bottom surface of the reinforcement member; a second biocompatible structure in the form of a third layer positioned adjacent a bottom surface of the mesh structure; and an anti-adhesion barrier in the form of a fourth layer positioned on a bottom surface of the second biocompatible structure, wherein the anti-adhesion barrier is a bioresorbable layer for reducing adhesion of underlying tissue and organ surfaces to the implantable prosthesis, wherein: the reinforcement member has a stiffness greater than the stiffness of the first and second biocompatible structures (110, 140); the first biocompatible structure, the reinforcement member, the mesh structure, the second biocompatible structure, and the anti-adhesion barrier are aligned and secured together; and the reinforcement member includes a central hub and a plurality of spokes extending radially from the central hub, characterised in that the implantable prosthesis is substantially umbrella-shaped, the spokes being formed from flexible material configured to allow the implantable prosthesis to be collapsed to a frustoconical or shuttlecock shape for insertion into an aperture and then expanded to conform to the shape of an inner wall of a body cavity. the reinforcement member has a stiffness greater than the stiffness of the first and second biocompatible structures (110, 140); the first biocompatible structure, the reinforcement member, the mesh structure, the second biocompatible structure, and the anti-adhesion barrier are aligned and secured together; and the reinforcement member includes a central hub and a plurality of spokes extending radially from the central hub, characterised in that the implantable prosthesis is substantially umbrella-shaped, the spokes being formed from flexible material configured to allow the implantable prosthesis to be collapsed to a frustoconical or shuttlecock shape for insertion into an aperture and then expanded to conform to the shape of an inner wall of a body cavity.