The MILD procedure, short for Minimally Invasive Lumbar Decompression, is an outpatient spine procedure that creates more space in a narrowed spinal canal to relieve pain and improve mobility. It treats a condition called lumbar spinal stenosis, where thickened tissue and bone gradually compress the nerves in the lower back, making it painful or difficult to stand and walk.
What Lumbar Spinal Stenosis Feels Like
Lumbar spinal stenosis typically develops slowly over years. The spinal canal in your lower back narrows as ligaments thicken and bone spurs grow inward, squeezing the nerves that run down to your legs. The hallmark symptom is called neurogenic claudication: pain, numbness, or heaviness in your legs that gets worse when you stand upright or walk and improves when you sit down or lean forward. Many people notice they can walk comfortably while pushing a shopping cart (because they’re leaning forward) but struggle to walk the same distance standing straight.
Over time, the walking distance you can manage shrinks. Some people find themselves avoiding errands, skipping activities, or relying on a cane. The MILD procedure is designed specifically for people with this pattern of symptoms who haven’t gotten lasting relief from more conservative treatments like physical therapy, anti-inflammatory medications, or spinal injections.
How the Procedure Works
The goal of MILD is to remove small portions of thickened ligament and bone that are crowding the spinal canal, giving the nerves more room. Unlike traditional open surgery for spinal stenosis (a laminectomy), MILD uses a tiny incision, roughly the size of a baby aspirin. The entire procedure is done through a small tube inserted into the back, guided by real-time imaging so the doctor can see exactly where they’re working without making a large cut.
No general anesthesia is required. Most patients receive moderate sedation and local numbing, which means you’re relaxed but not fully unconscious. No implants, screws, or stitches are involved. The procedure typically takes under an hour, and most people go home the same day.
Because the approach is so small, it preserves the structural integrity of the spine. There’s no cutting through major muscles or removing large sections of bone, which is what makes recovery significantly faster than traditional surgery.
MILD vs. Epidural Steroid Injections
Many people with spinal stenosis try epidural steroid injections first, and those injections can help temporarily. But a randomized study comparing the two approaches found that MILD delivered significantly better results. At 6 and 12 weeks after treatment, patients who received MILD reported greater pain reduction and better functional mobility than those who received steroid injections. Patient satisfaction scores also favored MILD, with satisfaction actually improving between the 6-week and 12-week marks rather than fading.
Steroid injections typically provide relief that lasts weeks to a few months and often need to be repeated. MILD addresses the physical cause of the narrowing rather than just dampening inflammation, which is why the results tend to be more durable.
Long-Term Results
The most comprehensive data comes from the MiDAS ENCORE clinical trial, which tracked patients for two years. At that point, disability scores had improved by an average of 22.7 points on the standard scale used to measure back-related limitations, and pain scores dropped by an average of 3.6 points. Both of these represent clinically meaningful improvements, not just statistically detectable ones. Improvements were consistent at the 6-month, 1-year, and 2-year follow-ups, meaning the benefits held steady rather than wearing off over time.
In practical terms, patients reported being able to stand longer, walk farther, and return to daily activities that stenosis had taken away from them.
Recovery Timeline
Recovery from MILD is notably quick compared to traditional spine surgery. On the day of the procedure, you should not drive, bathe, or swim. During the first week, you’ll need to avoid heavy lifting and strenuous activities. Depending on how physically demanding your job is, you may be able to return to work within a few days.
Most people notice improvement in their walking ability within a few weeks, though full results can continue developing over several months as inflammation from the procedure itself resolves. There are no major wound care requirements since the incision is so small, and most patients manage any post-procedure discomfort with over-the-counter pain relief.
Who Qualifies for MILD
MILD is designed for a specific subset of spinal stenosis patients. You’re generally a candidate if you have neurogenic claudication (the leg symptoms that worsen with standing and walking), imaging that confirms thickened ligament contributing to spinal canal narrowing, and a history of conservative treatments that haven’t provided adequate relief.
It’s not appropriate for every type of spinal stenosis. If narrowing is caused primarily by a herniated disc, severe instability, or stenosis at multiple levels, other treatments may be more suitable. The procedure works best when the thickened ligament is a major contributor to the compression.
Insurance and Medicare Coverage
Medicare has covered MILD under a national coverage determination since 2014, though with specific conditions. Coverage initially required participation in clinical evidence development programs, and CMS expanded the criteria in 2016 to include coverage through prospective studies using FDA-cleared devices. The key requirement from a coverage standpoint is that the procedure must be for symptomatic lumbar spinal stenosis that hasn’t responded to conservative therapy. Private insurance coverage varies, so checking with your plan before scheduling is important.