Last updated: May 2026. Author: Keith W. Schmidt, MD, Triple Board-Certified Interventional Pain Management Physician, Medical Director of the Neuroscience Institute Pain Program at Ascension Saint Alexius, Chair of the ASPN Healthy Longevity & Age-Related Pain Committee.
If you have lumbar spinal stenosis and your only options sound like wait, medicate, or have spine surgery, you are missing one of the best minimally invasive options in pain medicine. The MILD procedure (Minimally Invasive Lumbar Decompression) takes about 30 minutes, requires no general anesthesia, and is Medicare-covered for the right candidates. I perform MILD regularly in my Hoffman Estates practice. This is the patient guide I wish every spinal stenosis patient had before walking into my office.
What is the MILD procedure
MILD stands for Minimally Invasive Lumbar Decompression. It is an outpatient, fluoroscopy-guided procedure that treats lumbar central spinal canal stenosis caused by ligamentum flavum hypertrophy, a thickened ligament inside the spinal canal that pinches the nerves. The procedure is FDA-approved, Medicare-covered for qualifying patients, and performed through a needle-and-cannula access port about the size of a baby aspirin. There is no incision, no implanted hardware, and no general anesthesia.
How MILD actually works
Most patient-facing content gets this wrong. MILD does NOT shave bone. MILD does NOT remove disc material. It targets one specific cause of stenosis: the thickened ligamentum flavum.
If you imagine the spinal canal as a hollow tube your nerves run through, the ligamentum flavum is a layer of tissue that lines part of that tube. In some patients with chronic stenosis, that ligament thickens over time, sometimes from 2 mm to 5 mm or more, and starts squeezing the nerves at multiple levels. That squeezing causes the classic stenosis pattern: pain or heaviness in your legs that gets worse the longer you stand or walk, and gets better when you sit down or lean forward on a shopping cart.
During MILD, I use small specialized instruments (a tissue sculptor and a bone rongeur) introduced through a small access port to carefully thin out the ligamentum flavum. The targeted tissue removal is exactly enough to relieve the nerve pressure without disturbing the spine natural stability. No discs are removed. No screws or rods are placed. No fusion happens. Your spine anatomy is preserved.
The whole procedure runs about 30 to 45 minutes. You are awake or lightly sedated. You go home the same day, walking out under your own power.
Who is a candidate for MILD
The right candidate has all four of these:
- MRI-confirmed lumbar central canal stenosis caused primarily by ligamentum flavum hypertrophy, ideally 2.5 mm or greater thickening at one or more levels.
- Classic neurogenic claudication symptoms: leg pain, heaviness, weakness, or rubber-band sensation worse with standing/walking, better with sitting or leaning forward.
- Failed conservative care for at least 3 to 6 months: physical therapy, NSAIDs, and epidural steroid injections that gave only short-term relief.
- Stable enough for an outpatient procedure: most patients on blood thinners, with diabetes, or with cardiac disease can still have MILD with appropriate management.
The right candidate is NOT necessarily young. I perform MILD on patients in their 70s, 80s, and 90s regularly. The elderly population is exactly who MILD was designed for: the patient who is too risky for a fusion but still wants to be able to walk to the mailbox without sitting down halfway.
Who is NOT a good candidate
- Patients with primarily foraminal stenosis (nerve roots compressed at the side, not the central canal).
- Patients with spondylolisthesis (slipped vertebra) of grade 2 or higher.
- Patients with severe disc herniation as the primary pain generator.
- Patients whose symptoms are NOT classic neurogenic claudication.
What the evidence actually shows
The MOTION study (Pryzbylkowski et al., 2021 to 2022) is the most rigorous comparative evidence: 269 patients with lumbar stenosis and ligamentum flavum hypertrophy, half receiving MILD plus conservative care and half receiving conservative care alone. At one year, the MILD arm had significantly better pain reduction, walking distance, and Oswestry Disability Index scores. There were no major adverse events.
The ENCORE trial (Staats et al., 2018) is the longer-term real-world data: 100% of patients had measurable benefit, and the magnitude of benefit was sustained at 5 years.
Realistic expectations: 60 to 80% of well-selected patients get meaningful relief at 12 months, with most reporting improved walking distance and reduced reliance on medications. About 20 to 25% do not benefit enough and need a different intervention.
Medicare and insurance coverage in Illinois
Medicare covers MILD nationwide for qualifying patients with the right diagnosis. Medicare 2020+ policy is consistently favorable.
Commercial insurers in Illinois (Blue Cross Blue Shield, Aetna, UnitedHealthcare, Humana, Cigna) generally cover MILD for the same criteria, but every one requires prior authorization. The standard documentation:
- Recent MRI showing ligamentum flavum thickening
- Documentation of at least 3 months of failed conservative care
- Documentation of at least one prior epidural steroid injection
- Functional status documentation (walking distance, ODI, VAS pain scores)
My team handles all the prior authorization documentation. Typical timeline from green-light to scheduled is 2 to 4 weeks.
What the day-of looks like
Pre-procedure (1 week prior). A short office visit to review your MRI, confirm candidacy, and answer questions. We discuss whether to stop blood thinners.
Day of procedure. You arrive about an hour before. Vitals, IV started, brief pre-procedure conversation. You go to the procedure room, lie face down on a fluoroscopy table, get local anesthetic at the entry site, and (if you chose sedation) a small dose of conscious-sedation medication. The procedure runs 30 to 45 minutes; you may feel some pressure but typically not pain.
Post-procedure. Recovery in our suite for about 30 minutes: observation, snack, vitals stabilization. You walk out under your own power. No driving the day of the procedure.
Recovery timeline
- Day of procedure: Light walking around the house. Avoid lifting anything over 10 lbs. No driving.
- Days 1 to 3: Most patients feel some local soreness at the entry site, like a deep bruise. Tylenol or NSAIDs (if not on blood thinners) controls it.
- Days 4 to 7: Most patients return to desk-based work and most light activities.
- Weeks 2 to 4: Gradual increase in activity. Walking distance often improves in the first 2 weeks; full benefit at 4 to 6 weeks.
- Week 6: Full activity, including return to manual labor or physical therapy.
If MILD is not right for you, or if it does not work
About 20 to 25% of patients do not get adequate benefit from MILD alone. Options:
- Repeat MILD at the same or different level: sometimes targeting a second level decompresses an additional source.
- Spinal cord stimulation (SCS): for residual nerve pain after canal decompression. See my guide to SCS, DRG, and PNS.
- Surgical decompression / laminectomy: when MILD targeted approach is not enough.
- Fusion: when there is significant instability that decompression alone will not fix.
Why I sometimes combine MILD with epidurals or BVA
Many lumbar stenosis patients have multi-mechanism pain:
- Ligamentum flavum hypertrophy –> MILD
- Inflammation around irritated nerves –> epidural steroid injections
- Coincident vertebrogenic low back pain (Modic Type 1 or 2 endplate changes) –> basivertebral nerve ablation (Intracept/BVA)
For the right patient, I will combine MILD with sequential epidural injections plus, in some cases, basivertebral nerve ablation. Not every stenosis patient needs all three. Many do well with MILD alone.
Risks and complications
The complication rate for MILD is low, comparable to a complex epidural injection:
- Bleeding at the entry site: usually self-limited.
- Local infection: under 1%, manageable with antibiotics.
- CSF leak: uncommon (under 1%), usually managed conservatively.
- Nerve root irritation: temporary, typically resolves in days to weeks.
- Inadequate decompression: about 20 to 25%; rarely a complication, often a treatment failure.
What I do not see in MILD that I do see in fusions: hardware failure, adjacent segment disease, prolonged opioid dependence.
Frequently Asked Questions
Will MILD cure my stenosis?
No procedure cures stenosis the way you would cure a strep infection. The condition is structural; what changes after MILD is the degree of nerve compression. Most well-selected patients get sustained relief and improved walking distance.
How long does the benefit last?
Real-world data suggests sustained benefit at 5 years for the majority of patients who responded initially. Some re-progress and need additional interventions.
Is MILD better than a laminectomy?
Different procedures for different patients. MILD is faster, less invasive, and lower-risk, but does not decompress as much tissue as a laminectomy. For patients who can tolerate surgery and have severe stenosis, a laminectomy may be more durable. For elderly or high-risk patients, MILD is often the only realistic option.
Will I be awake?
Usually yes, under conscious sedation. Most patients are awake but relaxed.
Can I have MILD if I have a pacemaker?
Yes. Pacemaker is not a contraindication.
Can I have MILD on blood thinners?
Most blood thinners are paused 5 to 7 days before MILD. Some cannot safely be paused (mechanical heart valves, recent stents); in those cases I adjust the technique or coordinate with your cardiologist.
Will Medicare cover it?
For qualifying patients, yes. Medicare policy has been consistently favorable since 2020.
What if MILD does not work?
You have not burned any bridges. MILD does not change your anatomy in a way that prevents future treatment.
References
- Pryzbylkowski P, Bux A, Chandwani K, et al. Minimally Invasive Direct Decompression for Lumbar Spinal Stenosis: Impact of Multiple Prior Epidural Steroid Injections. Pain Management. 2022. (MOTION study)
- Staats PS, Chafin TB, Golovac S, et al. Long-term Safety and Efficacy of Minimally Invasive Lumbar Decompression: 5-Year Follow-up of the ENCORE Study. Pain Medicine. 2018.
- Mekhail N, Vallejo R, Coleman M, Benyamin RM. Long-term results of percutaneous lumbar decompression mild for spinal stenosis. Pain Practice. 2012;12(3):184-193.
- Sayed D, et al. (including Schmidt KW). ASPN Best Practices and Guidelines for the Interventional Management of Cancer-Associated Pain. Journal of Pain Research. 2021. PubMed 34295184
About the Author
Keith W. Schmidt, MD is a triple board-certified interventional pain management physician practicing in Hoffman Estates, Illinois. He is Medical Director of the Neuroscience Institute Pain Program at Ascension Saint Alexius Medical Center and Chair of the American Society of Pain and Neuroscience Healthy Longevity & Age-Related Pain Committee. He completed his Pain Medicine fellowship at Rush University Medical Center.
If you would like to discuss whether MILD might fit your case, my office accepts referrals from across the northwest Chicago suburbs. Call (847) 981-3630 or request an appointment online. We see patients from Hoffman Estates, Schaumburg, Arlington Heights, Palatine, Barrington, Rolling Meadows, Elk Grove Village, Inverness, Streamwood, and Des Plaines.