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 0C00X
Alteration of Upper Lip with Autol Sub, Extern Approach
Alteration of Upper Lip with Nonaut Sub, Extern Approach
Alteration of Upper Lip, External Approach
Alteration of Upper Lip with Synth Sub, Extern Approach