Causes and Treatment of Spinal Stenosis

< Causes and Classification of Spinal Stenosis >

• Because the definition of spinal stenosis can be too broad and arbitrary, a classification based on the characteristics of the disease was needed as a supplement. Accordingly, Arnoldi and others distinguished between congenital or developmental spinal stenosis and acquired spinal stenosis, and classified them according to anatomical location and the pathological findings causing the narrowing.

① Congenital, developmental spinal stenosis - idiopathic / achondroplasia

② Acquired spinal stenosis - degenerative / mixed type / spondylolytic spondylolisthesis / iatrogenic / traumatic / others

< Pathophysiology of Spinal Stenosis >

• The absolute criterion for central spinal canal stenosis is defined as an anteroposterior diameter of the spinal canal of less than 10 mm on computed tomography, and relative stenosis is defined as less than 13 mm.

Central spinal canal stenosis occurs due to hypertrophy of the ligamentum flavum, disc protrusion, spondylolisthesis, facet joint hypertrophy, degenerative facet joint cysts, and other causes. Usually, central spinal canal stenosis occurs when hypertrophied facet joints at the disc level invade the spinal canal, with hypertrophy of the inferior articular process of the upper vertebra being the main cause.

• Spinal canal stenosis caused by soft tissue hypertrophy accounts for 40% of central spinal canal stenosis and results from narrowing of the intervertebral disc space and subluxation of the facet joints, which reduces the vertical height of the spinal canal. In other words, soft tissues such as the ligamentum flavum, facet joint capsule, and posterior longitudinal ligament occupy a significant portion of the spinal canal cross-section and cause spinal stenosis. In patients with spinal stenosis caused by the soft tissues described above, when the lower back is extended, the ligamentum flavum invaginates into the spinal canal, worsening the degree of stenosis, so symptoms worsen with back extension.

< Treatment of Spinal Stenosis >

1. Conservative (non-surgical) treatment

• Because patients with spinal stenosis rarely experience rapid worsening of symptoms or loss of function, conservative treatment is performed first. Conservative treatment methods include changes in daily activities, appropriate exercise, physical therapy, lumbar braces, nonsteroidal anti-inflammatory analgesics, antidepressants, medication, epidural steroid injections, manual therapy, acupuncture, ultrasound, electrostimulation therapy, heat therapy, and others.

• There have been few studies on the outcomes of various non-surgical treatments.

2. Indications for surgical treatment

• Unless the patient has rapidly worsening neurological symptoms, such as rapidly weakening leg strength or impaired bowel and bladder function, surgery does not need to be performed urgently in patients with spinal canal stenosis. Surgery is indicated when neurological symptoms worsen, pain is not relieved by conservative treatment, or there is persistent disability and restriction of daily life.

3. Principles of surgical treatment

• The goal of surgery is to improve function, reduce pain, and prevent worsening of neurological symptoms. To achieve these goals, the compressed nerve must be decompressed.

• The most important thing is to perform sufficient decompression while preserving spinal stability so that later surgical failure can be prevented.

4. Surgical treatment methods

• Laminectomy is the standard surgical treatment for lumbar spinal canal stenosis. In addition, partial laminectomy can be performed on one or both sides, and there is also a method of laminoplasty in which access is obtained from one side and decompression is performed on both sides. In patients with spinal canal stenosis who do not have preoperative instability or deformity, if decompression is performed within a range that does not compromise stability, there is no need to add spinal fusion or instrumentation. However, in patients with spinal canal stenosis who have preoperative deformity or instability, there are many reports that adding fusion after decompression leads to better postoperative outcomes.

• Even in patients with spinal canal stenosis who do not have preoperative deformity or instability, if extensive decompression and facet joint resection are required, lumbar instability may occur as a result of surgery, so there are many opinions that additional fusion or pedicle screw fixation should be performed.

Source: Korea Disease Control and Prevention Agency National Health Information Portal