An implantable access port assembly (230, 335, 435) for use with a gastric band for the treatment of obesity, the implantable access port assembly comprising: a self-sealing septum (235, 350, 450) configured to be penetrable by a needle (240, 340); a housing (480, 580) including a septum retaining portion for holding the septum in place, and a base for defining an internal fluid reservoir (395, 455) and further defining a rivet receiving portion and a rivet engaging member, the housing further including a tubing connector configured to connect to a tubing for the movement of fluid into and out of the internal fluid reservoir; a mesh layer (330, 430, 530, 600) positioned beneath the housing, the mesh layer defining a plurality of spaces; and characterised by: a mesh rivet (360, 365, 465, 565, 765) including a head (468, 768), a body (469, 769) and a base (466, 481,766), the head configured to penetrate an opening of the plurality of spaces of the mesh layer and insertable into the rivet receiving portion to engage the rivet engaging member to hold the mesh rivet in place, the body for connecting the head to the rivet base, and the rivet base configured to have a surface area larger than the surface area of the opening penetrated by the head for holding the mesh layer between the rivet base and the housing, wherein the head comprises a tapered insertion portion and a housing engaging member (467, 767), wherein the tapered insertion portion of the head is configured to fit inside the rivet receiving portion of the housing, and wherein the housing engaging member is configured to contact the rivet engaging member of the housing inside the rivet receiving portion to prevent the head from exiting the rivet receiving portion of the housing. a self-sealing septum (235, 350, 450) configured to be penetrable by a needle (240, 340); a housing (480, 580) including a septum retaining portion for holding the septum in place, and a base for defining an internal fluid reservoir (395, 455) and further defining a rivet receiving portion and a rivet engaging member, the housing further including a tubing connector configured to connect to a tubing for the movement of fluid into and out of the internal fluid reservoir; a mesh layer (330, 430, 530, 600) positioned beneath the housing, the mesh layer defining a plurality of spaces; and characterised by: a mesh rivet (360, 365, 465, 565, 765) including a head (468, 768), a body (469, 769) and a base (466, 481,766), the head configured to penetrate an opening of the plurality of spaces of the mesh layer and insertable into the rivet receiving portion to engage the rivet engaging member to hold the mesh rivet in place, the body for connecting the head to the rivet base, and the rivet base configured to have a surface area larger than the surface area of the opening penetrated by the head for holding the mesh layer between the rivet base and the housing, wherein the head comprises a tapered insertion portion and a housing engaging member (467, 767), wherein the tapered insertion portion of the head is configured to fit inside the rivet receiving portion of the housing, and wherein the housing engaging member is configured to contact the rivet engaging member of the housing inside the rivet receiving portion to prevent the head from exiting the rivet receiving portion of the housing. a mesh rivet (360, 365, 465, 565, 765) including a head (468, 768), a body (469, 769) and a base (466, 481,766), the head configured to penetrate an opening of the plurality of spaces of the mesh layer and insertable into the rivet receiving portion to engage the rivet engaging member to hold the mesh rivet in place, the body for connecting the head to the rivet base, and the rivet base configured to have a surface area larger than the surface area of the opening penetrated by the head for holding the mesh layer between the rivet base and the housing, wherein the head comprises a tapered insertion portion and a housing engaging member (467, 767), wherein the tapered insertion portion of the head is configured to fit inside the rivet receiving portion of the housing, and wherein the housing engaging member is configured to contact the rivet engaging member of the housing inside the rivet receiving portion to prevent the head from exiting the rivet receiving portion of the housing.