OUP accepted manuscript

The MOTION study: Two-year results of a real-world randomized controlled trial of the mild® procedure for treatment of lumbar spinal stenosis

OBJECTIVE

The MOTION study is designed to measure the impact of percutaneous image-guided lumbar decompression as a first-line therapy on patients otherwise receiving real-world conventional medical management for lumbar spinal stenosis with neurogenic claudication secondary to hypertrophic ligamentum flavum. This prospective, multicenter randomized controlled trial uses objective and patient-reported outcome measures to compare the combination of the mild® percutaneous treatment and nonsurgical conventional medical management (CMM) to CMM-Alone.

METHODS

Test group patients received the mild procedure after study enrollment. Test and control groups were allowed conventional conservative therapies and low-risk interventional therapies as recommended by their physicians. Subjective outcomes included the Oswestry Disability Index, Numeric Pain Rating Scale, and Zurich Claudication Questionnaire. Objective outcomes included a validated Walking Tolerance Test, the rate of subsequent lumbar spine interventions, and safety data.

RESULTS

Two-year follow-up included 64 mild + CMM and 67 CMM-Alone patients. All outcome measures showed significant improvement from baseline for mild + CMM, whereas the majority of CMM-Alone patients had elected to receive mild treatment or other lumbar spine interventions by 2 years, precluding valid 2-year between-group comparisons. Neither group reported any device- or procedure-related adverse events.

CONCLUSIONS

The durability of mild + CMM for this patient population was demonstrated for all efficacy outcomes through 2 years. Improvements in walking time from baseline to 2 years for patients treated with mild + CMM were significant and substantial. The lack of reported device or procedure-related adverse events reinforces the strong safety profile of the mild procedure. These results provide support for early interventional treatment of symptomatic LSS with the mild procedure.

Lumbar Spinal Stenosis and Minimally Invasive Lumbar Decompression: A Narrative Review

Background

Lumbar spinal stenosis (LSS) is a common pain condition that causes lumbar back pain, radiating leg pain, and possible functional impairment. MILD is an emerging minimally invasive treatment for LSS. It is an image-guided percutaneous procedure designed to debulk hypertrophied ligamentum flavum. However, the exact short- and long-term efficacy, safety profile, indication criteria, and certain procedure details reported in medical literature vary.

Objective

This narrative review was to elucidate efficacy, safety profile, certain procedure details, advantages, and limitations of MILD.

Study Design

This is a narrative review.

Setting

All included articles are clinic trials including analytic studies and descriptive studies.

Methods

PubMed, Cochrane Library, and Scopus were searched. Only clinical trials of MILD procedure were included. Information of indications, contraindications, VAS scores, ODI scores, effective rate, efficacy durations, and certain procedure details was focused on.

Results

According to the literature, for the MILD procedure, the VAS score could be reduced from a pre-treatment level of 6.3-9.6 to a post-treatment level of 2.3-5.8. The ODI score could be reduced from a pre-treatment level of 38.8-55.3 to a post-treatment level of 27.4-39.8. The effective rate of the MILD procedure was reported to be 57.1%-88%. A 2-year postoperative stability of efficacy was also supported. One RCT study testified superior efficacy of MILD over epidural steroid injection.

Limitations

There is few high-quality literature in the review. Moreover, the long-term efficacy of MILD cannot be revealed according to the current literature.

Conclusion

Based on the reviewed literature, MILD is an effective and safe procedure. MILD can reduce pain intensity and improve functional status significantly. Therefore, it is a preferable option for LSS patients who failed conservative treatments, but not for those who require immediate invasive decompression surgery.

Percutaneous image-guided lumbar decompression and interspinous spacers for the treatment of lumbar spinal stenosis: A 2-year Medicare Claims Benchmark Study

OBJECTIVE

This prospective longitudinal study compares outcomes between Medicare beneficiaries receiving percutaneous image-guided lumbar decompression (PILD) using the mild® procedure and a control group of patients receiving interspinous spacers for the treatment of lumbar spinal stenosis (LSS) with neurogenic claudication (NC).

METHODS

Patients diagnosed with LSS with NC and treated with either the mild procedure or a spacer were identified in the Medicare claims database. The incidence of harms, the rate of subsequent interventions, and the overall combined rate of harms and subsequent interventions during 2-year follow-up after the index procedure were compared between the two groups and assessed for statistical significance with p = 0.05.

RESULTS

The study included 2229 patients in the mild group and 3401 patients who were implanted with interspinous spacers. The rate of harms for those treated with the mild procedure was less than half that of patients implanted with a spacer (5.6% vs. 12.1%, respectively; p < 0.0001) during 2-year follow-up. The rate of subsequent interventions was not significantly different between the two groups (24.9% and 26.1% for the mild and spacer groups, respectively; p = 0.7679). The total rate of harms and subsequent interventions for mild was found to be noninferior to spacers (p < 0.0001).

CONCLUSIONS

This comprehensive study of real-world Medicare claims data demonstrated a significantly lower rate of harms for the mild procedure compared to interspinous spacers for patients diagnosed with LSS with NC, and a similar rate of subsequent interventions during 2-year follow-up.