Automatic locking casper distractor

A vertebral distractor assembly comprising:

• a crossbar;
• a first distractor arm having a first end portion coupled to the crossbar and a second end portion with a first bore configured to receive a first coupling portion of a first pin;
• a second distractor arm having 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;
• and
• an automatic locking mechanism with an engagement portion having a first position wherein the engagement portion extends into the first bore, the automatic locking mechanism configured to allow movement of the engagement portion in a direction away from the longitudinal axis of the first bore in response to an anchoring pin being inserted into the first bore and forced against the engagement portion.

A method of distracting vertebrae comprising:

• engaging a first vertebra through a first distractor arm;
• implanting an anchoring pin in a second vertebra;
• receiving the anchoring pin within a bore in a second distractor arm;
• moving an engaging portion of a locking arm located within the bore in a direction away from a central axis of the bore;
• coupling the anchoring pin to the second distractor arm with the engaging portion;
• and
• moving one of the first distractor arm and the second distractor arm in a direction away from the other of the first distractor arm and the second distractor arm.