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 0KN3X
Release Left Neck Muscle, External Approach
Release Left Neck Muscle, Percutaneous Approach
Release Left Neck Muscle, Percutaneous Endoscopic Approach
Release Left Neck Muscle, Open Approach