MILD® Procedure for Spinal Stenosis: How a Minimally Invasive Treatment Can Improve Mobility
What is lumbar spinal stenosis, and why can it make walking difficult?
Lumbar spinal stenosis is a condition in which the spaces inside the lower spine become narrowed, potentially putting pressure on nearby nerves. One of the most common symptoms is neurogenic claudication, which can cause pain, numbness, tingling, heaviness, or weakness in the legs when standing or walking.
For some people, symptoms improve when sitting or bending forward. Over time, however, spinal stenosis can make routine activities such as walking through a grocery store, standing in line, or exercising increasingly difficult.
What is the MILD® procedure for spinal stenosis?
The MILD® procedure, also called minimally invasive lumbar decompression or percutaneous image-guided lumbar decompression (PILD), is a minimally invasive treatment for certain patients with lumbar spinal stenosis.
The MILD procedure is designed to address excess tissue from the ligamentum flavum, a ligament located along the back of the spinal canal. When this ligament becomes thickened, it can contribute to narrowing within the spinal canal. During MILD, a physician uses imaging guidance to remove small amounts of bone and thickened ligament tissue to create additional space for the nerves.
How can the MILD procedure improve mobility?
The MILD procedure can improve mobility by reducing pressure on spinal nerves when ligamentum flavum thickening is contributing to spinal canal narrowing.
Clinical studies have evaluated walking ability, pain, disability, and other measures of physical function following MILD. In the five-year follow-up of the MOTION randomized controlled trial, patients treated with MILD plus conventional medical management continued to demonstrate improvements in pain, disability, and walking tolerance compared with their baseline measurements.
Improving mobility does not necessarily mean eliminating every source of back or leg pain. Instead, the goal is to reduce the nerve compression responsible for neurogenic claudication so patients can stand and walk more comfortably.
Who may be a candidate for the MILD procedure?
A patient may be considered for MILD when symptoms, imaging findings, and previous treatments indicate that the procedure addresses an appropriate source of spinal narrowing.
Candidates commonly have lumbar spinal stenosis accompanied by neurogenic claudication and imaging evidence of hypertrophic ligamentum flavum. MILD may be considered when conservative treatments have not provided sufficient relief.
A physician will typically review the patient’s symptoms, medical history, physical examination, and MRI or other imaging before determining whether MILD is appropriate.
How is the MILD procedure performed?
The MILD procedure is performed through a small opening in the back while the physician uses real-time fluoroscopic imaging to guide the instruments.
The procedure focuses on removing small portions of bone and thickened ligament tissue that are contributing to the narrowing. Unlike traditional open spinal decompression, MILD does not require a large incision or placement of an implant. The procedure is generally performed in an outpatient setting.
The minimally invasive approach is intended to limit disruption to surrounding tissues while addressing the specific anatomical source of nerve compression.
Is MILD different from traditional spinal surgery?
Yes. MILD is different from traditional open lumbar decompression surgery in both technique and scope.
Traditional decompression surgery may involve a larger incision and more extensive removal of bone or other tissues. MILD uses image-guided instruments through a small access point to remove targeted portions of tissue contributing to spinal canal narrowing.
MILD is not appropriate for every type of spinal stenosis, and it should not be viewed as a replacement for all forms of spine surgery. The appropriate treatment depends on the anatomy causing compression, the patient’s symptoms, overall health, and previous treatment history.
What does recovery after the MILD procedure involve?
Recovery after MILD is generally designed to be less extensive than recovery from major open spine surgery. Because the procedure is minimally invasive, patients may be able to return to normal activities relatively quickly, although the exact recovery period varies.
Some patients experience soreness around the treatment area temporarily. Clinical studies have reported improvements in pain and function following the procedure, but individual results vary.
A physician will provide specific instructions regarding activity, exercise, medications, and follow-up care.
How effective is the MILD procedure for spinal stenosis?
Research suggests that MILD can reduce pain and improve physical function in appropriately selected patients with lumbar spinal stenosis and neurogenic claudication.
A 2026 systematic review covering 16 publications and 11 unique studies found consistent improvements in pain and disability following MILD. The review also found that the MOTION trial demonstrated sustained improvements in pain, disability, and walking tolerance through three years.
The five-year MOTION follow-up reported continued improvement from baseline, including a substantial increase in measured walking time.
These results do not mean that every patient will experience the same degree of improvement. Careful patient selection remains an important part of treatment planning.
Is the MILD procedure covered by Medicare?
Medicare coverage for percutaneous image-guided lumbar decompression has specific requirements. CMS expanded coverage under Coverage with Evidence Development for qualifying procedures using an FDA-approved or cleared device and clinical studies meeting specified requirements.
Coverage can depend on the patient’s circumstances, procedure, location, and current Medicare requirements. Patients should confirm coverage and eligibility with their physician and insurance provider before treatment.
When should someone ask about MILD for spinal stenosis?
Someone experiencing persistent leg pain, numbness, weakness, heaviness, or difficulty standing and walking because of lumbar spinal stenosis may benefit from discussing treatment options with a spine or pain specialist.
The MILD procedure may be an option when imaging shows ligamentum flavum thickening contributing to spinal stenosis and conservative treatment has not adequately improved symptoms. A comprehensive evaluation can determine whether MILD, another minimally invasive treatment, physical therapy, medication, or surgical decompression is more appropriate.
For patients whose spinal stenosis is limiting their ability to walk and remain active, understanding the available treatment options can be an important step toward improving mobility and quality of life.
