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 0JN0X
Release Scalp Subcu/Fascia, Extern Approach
Release Scalp Subcutaneous Tissue and Fascia, Perc Approach
Release Scalp Subcutaneous Tissue and Fascia, Open Approach