REMOVABLE SPLIT CANNULA FOR PLACEMENT OF ELECTRODES

A method of inserting an electrode into a cranial cavity of a cranium can include determining a length, between a target within the cranial cavity and a proximal end of a multipiece cannula, of the electrode for insertion of the electrode to the target. A distal end of the electrode can be inserted through a multipiece cannula supported by an instrument holder of a surgical arm. The surgical arm can be positioned such that a distance from the target to the proximal end of the cannula is equal to the length. The electrode can be fed through the cannula and through the anchor bolt into the cranial cavity. Feeding of the electrode through the cannula and into the cranial cavity can be stopped when the length of the electrode fed into the cavity reaches the length between the proximal opening of the multipiece cannula and the target.