Lumbar spinal stenosis (LSS) may refer to one or more of the following anatomical states:
●Intraspinal (central) stenosis
● Lateral recess stenosis
● nerve root hole stenosis
The cause of LSS can be congenital or acquired.
Spinal degeneration (Spondylosis, manifested as rigidity or stiffness) or degenerative arthritis affecting the spine is the most common cause of LSS, usually involving individuals over 60 years of age. Obesity can also be a risk factor. Progressive disc degeneration, trauma, or other factors caused by aging can cause disc herniation and/or decreased disc height and consequent increased load on the posterior vertebral structures, including the facet joints. Articular joint disease and osteophyte formation followed by hypertrophy of the ligamentum flavum. All of these pathological processes (osteoarticular osteophytes, ligamentum flavum, and intervertebral disc bulging) can invade the central spinal canal and nerve root canal.
Spondylolisthesis, that is, a vertebral body moving forward or backward relative to another adjacent vertebral body, may also occur, causing the spinal stenosis to worsen. The L4-5 segment is most often involved, followed by L5-S1 and L3-4. In patients with lumbar stenosis, degenerative changes can affect the isthmus of the vertebral arch, leading to instability of the lumbar spine, resulting in fractures and vertebral body displacement.
Other acquired causes include:
● Space-occupying lesions (lipoma, synovial cysts and neurocysts, tumors).
● Traumatic and postoperative factors (fibrosis).
● Skeletal disease (Paget's disease, ankylosing spondylitis, rheumatoid arthritis, and diffuse idiopathic bone hypertrophy).
The congenital and developmental causes of LSS include the following:
● Dwarfism (chondral hypoplasia, Morquio syndrome, other vertebral dysplasia).
● Insufficiency of the spinal canal (spinal fissure, spondylolisthesis, spinal meningocele).
- Neurogenic (or pseudo) claudication is a hallmark of LSS, which increa