Abstract
Background and Study Aims The technique and instrumentation of percutaneous endoscopic lumbar diskectomy (PELD)
have significantly improved. Thus its indications have been gradually expanding. Down-migrated
disk, in particular, is regarded inaccessible by rigid instrumentation due to poor
visualization and limited accessibility. We introduce a combination of transforaminal
and interlaminar PELD for extensive down-migrated disk herniation at the L4–L5 level.
Patients and Methods In the first case, a 48-year-old man had left L5 radicular pain. Magnetic resonance
imaging (MRI) showed that L4–L5 disk herniation extended to the L5 lower end-plate
level. In the second case, a 39-year-old man presented with right L5 and S1 radiculopathy.
MRI showed right huge extensive down-migrated disk herniation from the L4–L5 disk
space to the S1 pedicle level. Back pain and leg pain were measured using the visual
analog scale (VAS). In the first case, transforaminal PELD with foraminoplasty removed
the disk fragment from the L4–L5 disk space to the mid-L5 pedicle level. Interlaminar
PELD removed the remaining disk below the mid-L5 pedicle. In the second case, first,
contralateral (left) transforaminal PELD at L4–L5 removed disk fragments located at
the subannular and subligamentous area as well as the upper part of the down-migrated
disk herniation. Second, interlaminar PELD via an ipsilateral (right) L5–S1 interlaminar
space removed the remains of the extensively down-migrated disk herniation.
Results In the first case, the VAS scores for back and leg pain were improved from 6 and
8 to 2 and 1, respectively. Postoperative MRI showed complete removal of the disk
fragment. In the second case, the VAS scores for back and leg pain improved from 7
and 9 to 3 and 1, respectively, after PELD. Postoperative MRI showed complete removal
of a huge disk herniation. Both patients were discharged the day after PELD. Follow-up
examinations showed no recurrence.
Conclusions It is difficult to remove entire disk fragments using only a transforaminal or interlaminar
approach for extensive down-migrated disk herniation. Therefore a combination of transforaminal
and interlaminar PELD may be effective for extensive down-migrated disk herniation
at L4–L5.
Keywords
percutaneous endoscopic lumbar diskectomy - transforaminal - interlaminar - down-migrated
disk herniation - foraminoplasty
