A medical device (100, 200), comprising: a shaft extending from a proximal end toward a distal end, the shaft extending along a longitudinal axis and the shaft including a lumen extending from the proximal end toward the distal end; a first stapling head at the distal end, the first stapling head configured to contain one or more staples, and the first stapling head having a block disposed within, and movable relative to, the first stapling head; a second stapling head at the distal end; and a pushing element extending through the lumen, the pushing element being movable from a first position to a second position, wherein transition of the pushing element from the first position to the second position urges the block to move toward the second stapling head along a radially-inward directed path that is substantially perpendicular to the longitudinal axis of the shaft to deploy the one or more staples; wherein the second stapling head includes a planar face extending substantially perpendicular to the longitudinal axis, wherein the planar face is an anvil configured to bend the one or more staples into tissue upon contact with the one or more staples, wherein the pushing element also includes a third position and a fourth position, before the pushing element is moved from the first position to the second position, and wherein movement of the pushing element from the third position to the fourth position causes the first stapling head to move toward the second stapling head, and wherein the first stapling head also moves toward the second stapling head along the radially-inward directed path that is substantially perpendicular to the longitudinal axis of the shaft. a shaft extending from a proximal end toward a distal end, the shaft extending along a longitudinal axis and the shaft including a lumen extending from the proximal end toward the distal end; a first stapling head at the distal end, the first stapling head configured to contain one or more staples, and the first stapling head having a block disposed within, and movable relative to, the first stapling head; a second stapling head at the distal end; and a pushing element extending through the lumen, the pushing element being movable from a first position to a second position, wherein transition of the pushing element from the first position to the second position urges the block to move toward the second stapling head along a radially-inward directed path that is substantially perpendicular to the longitudinal axis of the shaft to deploy the one or more staples; wherein the second stapling head includes a planar face extending substantially perpendicular to the longitudinal axis, wherein the planar face is an anvil configured to bend the one or more staples into tissue upon contact with the one or more staples, wherein the pushing element also includes a third position and a fourth position, before the pushing element is moved from the first position to the second position, and wherein movement of the pushing element from the third position to the fourth position causes the first stapling head to move toward the second stapling head, and wherein the first stapling head also moves toward the second stapling head along the radially-inward directed path that is substantially perpendicular to the longitudinal axis of the shaft.