An implantable device having an adjustable passage therethrough. The passage may be adjustable to occlude or otherwise to regulate access or flow of materials therethrough. An elongated element may be inserted into the passage when in a closed configuration to selectively open the passage. For instance, the implantable device may be a tubular device with a twisted region closing the passage therethrough, and the elongated device may be configured to engage such twisted region and to be rotated to untwist the closed region. An additional tubular device with a passage therethrough may be inserted into the passage of the implantable device to hold open the passage for a selected period of time.