US Patent 8197488 Automatic locking casper distractor

A vertebral distractor system includes a crossbar and a first distractor arm having a first end portion coupled to the crossbar and a second end portion with a first bore configured to axially receive a first coupling portion of a first pin. A second distractor arm includes a third end portion coupled to the crossbar and a fourth end portion with a second bore configured to receive a second coupling portion of a second pin. A first pin locking mechanism is configured to couple the first coupling portion and the first distractor arm within the first bore such that when the first coupling portion and the first distractor arm are coupled, movement of the first pin outwardly of the first bore is not allowed.