A surgical apparatus may include a staple holder, an anvil connected to and movable relative to the staple holder, and at least one axle extending outward from the anvil; and an overtube slidable relative to the end effector, the overtube including at least one slot defined therein; where each slot receives a corresponding axle. A surgical method for treating tissue of a patient may include providing an end effector that includes a staple holder and an anvil connected to and movable relative to the staple holder, and an overtube slidable relative to said end effector, making an incision in the patient; inserting the end effector and at least part of the overtube through the incision in a first, insertion configuration in which substantially no gap exists between the anvil and staple holder, and moving the overtube relative to the end effector to open the end effector to a second, unclamped position where at least part of the anvil is spaced apart from the staple holder.