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 0SN4X
Release Lumbosacral Disc, Percutaneous Endoscopic Approach
Release Lumbosacral Disc, Percutaneous Approach
Release Lumbosacral Disc, Open Approach
Release Lumbosacral Disc, External Approach