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 0NQ4X
Repair Left Parietal Bone, Percutaneous Endoscopic Approach
Repair Left Parietal Bone, External Approach
Repair Left Parietal Bone, Percutaneous Approach
Repair Left Parietal Bone, Open Approach