Improved percutaneous endoscopic translaminar approach for lumbar foraminal stenosis at L5/S1

The operative approach for lumbar foraminal stenosis (LFS) is one of the most challenging for spinal surgeons.[1-3] Excessive removal of the dorsal area of the foramen in a posterior approach can easily lead to iatrogenic spondylolysis, subsequently increasing lumbar instability and spondylolisthesis. A posterolateral approach is one solution to this problem. However, LFS in the L5/S1 region is difficult to treat using a posterolateral approach, because of an anatomic peculiarity: the lateral aspect of the foramen is surrounded by the L5 transverse process, sacral ala, and hypertrophic facet joint. LFS usually develops after the age of 50 and is one of the most common degenerative spinal diseases in the elderly. As a result of this the vertebral height generally decreases, depending on the degree of disc degeneration. Compared with the younger patients without disc degeneration, the surgical access becomes more difficult.