Apparatus and methods are described, including apparatus for treating a cavity in a human body, the apparatus including a delivery tube. A bather device has a collapsed configuration and an expanded configuration, the barrier device moving from the collapsed configuration to the expanded configuration upon being deployed from the delivery tube. A pushing element, slidably disposed within a lumen of the delivery tube, is configured to deploy the barrier device from the delivery tube by pushing the bather device. One or more bather-deployment elements are coupled to the barrier device and to the pushing element, the bather-deployment elements being configured to conformingly contact the barrier device with tissue surrounding the cavity. Other applications are also described.
