The Effect of Indirect Decompression Through Extraforaminal Interbody Fusion for Degenerative Lumbar Disease.

Purpose: Extraforaminal lumbar interbody fusion as with other methods that involve the mechanism of indirect decompression, the discussion not only focuses on the benefit of minimizing the risk of thecal sac injury and postoperative scarring, but also on the risk of insufficient decompression in the affected neural structures during the reduction of the affected segment.

Methods: Eighty-two patients presenting with degenerative lumbar disease with segmental instability underwent ELIF combined with transpedicular fixation and circumferential fusion. Clinical and radiographic evaluations were performed.

Results: The mean ODI significantly improved from 63.4 preoperatively to 32.3 1 year postoperatively. The mean VAS back pain significantly improved from 5.95 to 2.63 postoperatively and VAS (leg pain) improved from 6.04 to 2.44. The mean CSA increased from 103  mm preoperatively to 169  mm postoperatively. The median extension ratio of CSA was 33%. Disc height, segmental disc angle, and lumbar lordosis also improved significantly. Only three (3.7%) patients were revised using direct central decompression due to neurologic deterioration.

Conclusion: Spinal stenosis was resolved successfully by indirect decompression through extraforaminal interbody fusion via a transmuscular limited approach.