Spinal Stenosis recommendations from MIST 2.0

Spinal stenosis is a narrowing of the spaces in your spine and can compress your spinal cord and nerve roots exiting each vertebra. Age-related changes in your spine are a common cause. Symptoms include back and/or neck pain, and numbness, tingling and weakness in your arms and legs.

Lumbar spinal stenosis is a condition that affects 11 percent of the public, and the number of minimally invasive treatments for LSS are multiplying rapidly. This rapidly evolving field requires guidance to optimize patient outcomes.

In 2019, the minimally invasive spinal treatment (MIST) guidelines were authored by a group of physicians and health care experts from the fields of anesthesiology, physiatry, orthopedic surgery and neurosurgery. MIST included 11 recommendations regarding spinal treatments that could be used algorithmically to improve therapeutic efficacy.

Soon afterwards another group, MIST 2.0, was formed to evaluate new therapies and include them in the treatment algorithm formulated by the first committee. Among the new topics investigated by MIST 2.0 are

  • Epidural steroid injections (ESI)
  • Percutaneous image-guided lumbar decompression (PILD)
  • Interspinous spacers
  • Open decompression
  • Interspinous fusion
  • Neurostimulation
  • Intrathecal drug delivery systems (IDDS)

What Is Lumbar Spinal Stenosis?

Lumbar spinal stenosis is quite common in the United States with more than 200,000 new cases annually. This condition involves the narrowing of the spinal canal which houses the spinal cord, in the lower back.

Among the symptoms of lumbar spinal stenosis are difficulty walking, pain or numbness in the legs, and a need to lean forward to alleviate pressure or pain on the lower back. In more severe cases, patients may have loss of bladder or bowel control.

Lumbar spinal stenosis is most common among people aged 50 and over because it is at this age that osteoarthritis—deterioration of joints—occurs. Other causes of LSS include

  • Spinal injury
  • Cancerous growth
  • Bone diseases
  • Prior spinal surgery
  • Rheumatoid arthritis

Why Treating Lumbar Spinal Stenosis Is So Important

Although LSS has an 11 percent prevalence in the general population, it is estimated that among those 60 or older it may be as common as 47 percent. Lumbar spinal stenosis is the most common reason for spine surgery among those over the age of 65.

Lumbar spinal stenosis presents most commonly with pain in one or both legs. This pain may inhibit walking which in turn may degrade the quality of their life. If the LSS is left untreated, it is possible that the patient could be permanently disabled due to paralysis or such severe muscle weakness that they are wheelchair-bound.

In addition to the prospect of chronic pain and paralysis, untreated lumbar spinal stenosis may lead to nerve damage that could prevent you from controlling your bladder or bowels. This kind of nerve damage may be corrected with a surgical procedure in some cases, but it is best to avoid it in the first place, if possible.

MIST Key Points

Unlike the initial MIST algorithm that consisted of 11 key steps, MIST 2.0 has 13 that cover a range of topics from diagnostics through various treatments. These flow points can be summarized in the following:

  1. Diagnosing lumbar spinal stenosis should rest on imaging as well as medical history because traditional imaging may be less effective at identifying spinal stenosis.
  2. MRI and CT imaging should be optimized for lateral recess and central canal stenosis. New research suggests that conventional MRI imaging may overestimate the lateral recess dimensions in LSS patients.
  3. Certain patients may benefit from hyperlordotic positioning (in which the lumbar is curved dorsally) rather than the traditional supine positioning. This non-traditional positioning may provide a more accurate picture of the spinal canal.
  4. Standing flexion-extension imaging is recommended for dynamic instability analysis. Dynamic imaging supported by artificial intelligence may provide truly powerful insights into lumbar spinal stenosis diagnostics.
  5. Differentiating lumbar spinal stenosis from other back and leg pain conditions may require a wide range of diagnostic testing. An accurate diagnosis is essential for successful patient outcomes.
  6. Percutaneous image-guided lumbar decompression or PILD is recommended for patients with hypertrophied ligamentum flavum. This minimally invasive procedure reduces the size of lamina and ligaments intruding into the spinal canal.
  7. Interspinous spacers may be a treatment option for mild to moderate LSS if there is no dynamic instability between spinal vertebrae.
  8. Interspinous fusion should be considered for patients with degenerative spine disease and mild to moderate vertebral misalignment.
  9. Physicians should consider the use of Intrathecal Drug Delivery Systems for patients with moderate to severe pain and when other pain treatment options fail or are unavailable.
  10. Open decompression is recommended when there is a clearly favorable benefit to risk ratio especially when there is a rapid progression of LSS symptoms.
  11. Spinal cord stimulation should only be considered after minimally invasive decompression has failed or is not available as a treatment option.
  12. Epidural steroid injections should be included in the LSS treatment algorithm after oral medications, physical therapy and exercise have been tried without improvement.
  13.  Epidural steroid injections should only be repeated if a prior round of treatment produced significant symptom improvement.

Major Differences between MIST 1.0 and MIST 2.0

MIST 1.0 based its recommendations primarily on the architecture of the spinal stenosis because at the time, there was less analytical data available to physicians and because it was the first set of treatment guidelines of this kind. MIST 2.0, however, considers the presence and nature of spondylolisthesis and micro-instability.

Furthermore, new tools have come online for remediating lumbar spinal stenosis. For example, a new spinal fusion device is now available that could not have been included in MIST 1.0.

Patient Recommendations

The MIST 2.0 treatment algorithm is intended for use with patients who exhibit mild to moderate spinal stenosis and are therefore likely to respond to minimally invasive therapies. Patients suffering from severe lumbar spinal stenosis are likely to benefit from a referral to a back pain specialist.

The good news for patients is that in recent years, new techniques have become available that are less invasive and therefore present less risk. This trend is likely to continue with ongoing refinements of current LSS therapies as well as advances in therapeutic technologies for the field in general. MIST will continue to monitor the field and use exhaustive investigation of emerging therapies to optimize its treatment recommendations.

Article written by: Dr. Robert Moghim – CEO/Founder Colorado Pain Care

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