Endoscopic and Microscopic Interlaminar Discectomy for the Treatment of Far-Migrated Lumbar Disc Herniation: A Retrospective Study with a 24-Month Follow-Up

Abstract

Purpose: Percutaneous endoscopic lumbar discectomy for the treatment of far-migrated lumbar disc herniation (LDH) is clinically challenging. The aim of this study was to compare the efficacy and safety of interlaminar endoscopic lumbar discectomy (IELD) and interlaminar microscopic lumbar discectomy (IMLD) for the treatment of far-migrated LDH.

Materials and methods: We retrospectively analyzed 50 consecutive cases of far-migrated LDH treated by IELD or IMLD. Clinical data and outcomes were assessed before the operation and 1 day and 3, 12, and 24 months after the surgery using the visual analog scale (VAS) and Oswestry disability index (ODI). Modified MacNab criteria were used to evaluate patient satisfaction at the 24-month follow-up.

Results: A significant reduction in leg pain and improvement in ODI (P<0.01) were observed in both groups after surgery. Lower back pain (LBP) was reduced at 24 months postsurgery in the IELD group (P<0.05) but not in the IMLD group (P>0.05). There were significant intergroup differences in VAS LBP score at 1 day and 24 months postsurgery (p=0.01 and 0.02, respectively) and in ODI at 24 months (p=0.03). The rate of excellent or good outcome was 90.32% with IELD and 78.95% with IMLD (p=0.55). Hospital stay and time to ambulation were shorter in the IELD group than in the IMLD group, but the former had a longer operative time (p<0.01). Low and comparable complication rates were reported in the IELD (16.13%) and IMLD (10.53%) groups (p=0.70).

Conclusion: Both IELD and IMLD achieve favorable clinical results in the treatment of far-migrated LDH, with only minor complications. Compared to IMLD, LBP was significantly reduced with IELD presumably because it involved less trauma.

Keywords: downward migration; highly migrated lumbar disc herniation; interlaminar approach; minimally invasive spinal surgery; upward migration.

Figure 1

Definition of far-migrated LDH used in this study. Note: Data adapted from Lee et al and Ahn et al.

Figure 2

Clinical status and outcomes. VAS for lower back pain (A) and leg pain (B) and Oswestry disability index (C) were evaluated preoperatively (Pre-op) and at 1 day (1D), 3 months (3M), 12 months (12M), and 24 months (24M) postoperatively.

Figure 3

Pre- and postoperative images of far-migrated LDH. T2-weighted axial MR images of the L4–L5 disk level showing disc extrusion (A) and far down-migrated disc material from the L4–L5 disc level to the L5 lower end plate (B). Intraoperative radiograph showing the placement of the working channel placed between the pedicle and the spinous process (C) and under the pedicle of L5 through limited resection of the lamina and ligamentum flavum (D). Endoscopic view showing complete decompression of L5 nerve root above shoulder and axilla (E). The nucleus pulposus between the dural sac and L5 nerve root was completely removed (F). Postoperative axial magnetic resonance images of the L4–L5 level (G) and T2-weighted sagittal (H).