A medical device (100, 1000) for use with a fluid filler material and for occupying a space within a patient's body, the medical device comprising: a first fluid impermeable surface material (102, 228, 328) forming a device body having an interior reservoir (104, 236, 304), the device body having a deployment profile and expandable to an active profile upon receiving the fluid filler material within the interior reservoir; a fluid conduit (114, 332); a fluid valve (112, 1110) comprising at least one valve wall defining a fluid tunnel having a first end being exterior to the interior reservoir and a second end extending within the interior reservoir and an elongated passage extending therethrough, the fluid conduit extending through the elongated passage of the fluid tunnel, and wherein the at least one valve wall is predisposed to block flow through the fluid tunnel following removal of the conduit; and a release channel formed by an interior of a second fluid impermeable material (102, 124), wherein the release channel is in fluid communication with the interior reservoir and is temporarily fluidly sealed by a release material (106, 1400) located in the interior reservoir about an exterior of the second fluid impermeable material to mechanically secure the second fluid impermeable material to fluidly seal the release channel and to prevent fluid transfer to or from the patient's body until the fluid filler material reduces the structural integrity of the release material to unseal the release channel characterised by a retaining element (1030, 1032, 1040) attaching the fluid conduit to the at least one valve wall to hold the fluid conduit within the fluid tunnel until the retaining element decouples from the at least one valve wall to allow removal of the fluid conduit by applying a tensile force on the fluid conduit. a first fluid impermeable surface material (102, 228, 328) forming a device body having an interior reservoir (104, 236, 304), the device body having a deployment profile and expandable to an active profile upon receiving the fluid filler material within the interior reservoir; a fluid conduit (114, 332); a fluid valve (112, 1110) comprising at least one valve wall defining a fluid tunnel having a first end being exterior to the interior reservoir and a second end extending within the interior reservoir and an elongated passage extending therethrough, the fluid conduit extending through the elongated passage of the fluid tunnel, and wherein the at least one valve wall is predisposed to block flow through the fluid tunnel following removal of the conduit; and a release channel formed by an interior of a second fluid impermeable material (102, 124), wherein the release channel is in fluid communication with the interior reservoir and is temporarily fluidly sealed by a release material (106, 1400) located in the interior reservoir about an exterior of the second fluid impermeable material to mechanically secure the second fluid impermeable material to fluidly seal the release channel and to prevent fluid transfer to or from the patient's body until the fluid filler material reduces the structural integrity of the release material to unseal the release channel characterised by a retaining element (1030, 1032, 1040) attaching the fluid conduit to the at least one valve wall to hold the fluid conduit within the fluid tunnel until the retaining element decouples from the at least one valve wall to allow removal of the fluid conduit by applying a tensile force on the fluid conduit.