BlueCross BlueShield of Tennessee Medical Policy Manual

Image-Guided Minimally Invasive Lumbar Decompression for Spinal Stenosis


Image-guided minimally invasive lumbar decompression (IG-MILD) describes a percutaneous procedure for decompression of the central spinal canal in individuals with lumbar spinal stenosis and hypertrophy of the ligamentum flavum.  In contrast to surgical decompression, this procedure is performed solely under fluoroscopic guidance (e.g., without endoscopic or microscopic visualization of the work area). This procedure has been proposed for the treatment of central stenosis only, without the capability of addressing nerve root compression or disc herniation, should it be required.

During the IG-MILD (e.g. X-Sten MILD, mild® Device Kit, Vertos mild®) procedure, the epidural space is filled with contrast medium under fluoroscopic guidance. Using a 6-gauge cannula that is clamped in place with a back plate, single use tools (portal cannula, surgical guide, bone rongeur, tissue sculptor, and trocar) are used to resect thickened ligamentum flavum and small pieces of lamina. The tissue and bone sculpting is conducted under fluoroscopic guidance, with additional contrast media added throughout the procedure to aid visualization of the decompression. The process is repeated on the opposite side for bilateral decompression of the central canal.




Available studies have limitations that include: non-controlled trials, case series, non-blinded studies, and small number of participants. Well-designed studies that include: a larger number of participants at multi-centers, use of clear patient selection criteria, measures of outcome using standardized tools, comparison to conservative management, comparison with and without an anesthetic agent and longer term outcomes are needed to validate the use/safety/effectiveness of this technology.

The Vertos mild® tool kit initially received 510(k) marketing clearance as the X-Sten MILD Tool Kit (X-Sten Corp.) from the U.S. Food and Drug Administration in 2006. Vertos mild® tool kit instructions for use state that the devices are not intended for disc procedures but rather for tissue resection at the perilaminar space, within the interlaminar space and at the ventral aspect of the lamina.


Benyamin, R. & Staats, P. (2016). MILD® is an effective treatment for lumbar spinal stenosis with neurogenic claudication: MiDAS ENCORE randomized controlled trial. Pain Physician, 19, 229-242. (Level 1 evidence)

BlueCross BlueShield Association. Evidence Positioning System. (4:2018). Image-guided minimally invasive lumbar decompression for spinal stenosis (7.01.126). Retrieved January 22, 2019 from  (12 articles and/or guidelines reviewed)

Centers for Medicare & Medicaid (2017, June). NCD for percutaneous image-guided lumbar decompression for lumbar spinal stenosis (150.13). Retrieved March 14, 2017 from

Chopko, B. W. (2011). A novel method for treatment of lumbar spinal stenosis in high-risk surgical candidates: Pilot study experience with percutaneous remodeling of ligamentum flavum and lamina. Journal of Neurosurgery, Spine, 14 (1), 46-50. (Level 4 evidence)

Chopko, B. W. (2013). Long-term results of percutaneous lumbar decompression for LSS: Two-year outcomes. Clinical Journal of Pain, 29 (11), 939-943. (Level 4 evidence)

Deer, T.R., Grider, J.S., Pope, J.E., Falowski, S., Lamer, T.J., Calodney, A., et al. (2018). The MIST guidelines: the lumbar spinal stenosis consensus group guidelines for minimally invasive spine treatment. Pain Practice, 19 (3), 250-274. (Level 2 evidence)

Kreiner, D., MacVicar, J., Duszynski, B., & Nampiaparampil, D. (2014). The mild® procedure: a systematic review of the current literature. Pain Medicine, 15, 196-205. (Level 4 evidence)

Levy, R. M., & Deer, T. R. (2012). Systematic safety review and meta-analysis of procedural experience using percutaneous access to treat symptomatic lumbar spinal stenosis. Pain Medicine, 13 (12), 1554-1561. (Level 4 evidence)

Schomer, D. F., Solsberg, D., Wong, W., & Chopko, B. W. (2011). mild(®) lumbar decompression for the treatment of lumbar spinal stenosis. Neuroradiology Journal, 24 (4), 620-626. (Level 1 evidence)

Staats, P. & Benyamin, R. (2016). MiDAS ENCORE: Randomized controlled clinical trial report of 6-month results. Pain Physician, 19, 25-37. (Level 2 evidence)

U. S. Food and Drug Administration. (2010, February). Center for Devices and Radiological Health. 510(k) Premarket Notification Database. K093062. Retrieved April 26, 2012 from

Wang, J. J., Bowden, K., Pang, G., & Cipta, A. (2013). Decrease in health care resource utilization with MILD. Pain Medicine, 14 (5), 657-661. (Level 4 evidence)




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