The Approach External is identified by letter "X" and occupies the 5th position in the ICD10-PCS procedure code structure.
Below a selection of ICD 10 PCS codes related to 0RN0X
Release Occipital-cervical Joint, External Approach
Release Occipital-cervical Joint, Percutaneous Approach
Release Occipital-cervical Joint, Perc Endo Approach
Release Occipital-cervical Joint, Open Approach