A stent-deployment assembly for use with a guidewire comprises a biliary stent and an elongated stent-conveyance tube comprising a guidewire-retaining segment that includes respective distal and proximal apertures defining a guidewire-path therethrough, and a lengthways laterally-breachable portion. In a stent-advancement configuration, the guidewire passes through the respective apertures so as to interiorly traverse the guidewire-retaining segment, and the stent is arranged to surround a stent-conveyance tube segment that is proximally displaced from the guidewire-retaining segment, for advancement of the stent together with the stent-conveyance tube along the guidewire into a body lumen of a human subject. When the stent is disposed, in the stent-advancement configuration, at a target deployment location within the lumen, a proximal-direction withdrawal of the stent-conveyance tube is effective to cause the guidewire to breach the laterally-breachable portion of the guidewire-retaining segment so as to decouple the guidewire from the tube without longitudinal displacement of the guidewire.