An axillary type of lumbar disc herniation is a common cause of incomplete removal of herniated disc material. Although axillary type disc herniations may seem to be removed easily by conventional Percutaneous Endoscopic Lumbar Discectomy (PELD), there are actually remaining herniated disc fragments located in the epidural space compressing the traversing nerve root in the cases of Choi et al. 1). What is usually removed are the subannular disc protrusions within the disc space.
There are 3 important points to remember. First, it is necessary to do adequate release of the entire disc fragment from the annulus before grasping the tail or tip of the herniated disc and pulling it out. If this is not done, an epidural disc fragment remnant will remain when the intradiscal portion of the herniation is pulled out. Second, the herniated disc removal is to be done at the level of the bevel cannula opening. For example, in the case of an axillary-located disc with a downward migrated fragment, the fragment can be covered by the working cannula bevel. When the working cannula bevel is rotated and opens caudally, we should carefully search for the herniated disc fragment in the epidural space. Third, it is not uncommon to have multiple disc fragments in a disc herniation. It may be possible to have some retained fragments while some have been removed 2).