Minimally Invasive Direct Decompression for Lumbar Spinal Stenosis: Impact of Multiple Prior Epidural Steroid Injections.

Background: A modified algorithm for the treatment of lumbar spinal stenosis with hypertrophic ligamentum flavum using minimally-invasive lumbar decompression (mild(R))was assessed, with a focus on earlier intervention. Patients & methods: Records of 145 patients treated with mild after receiving 0-1 epidural steroid injections (ESIs) or 2+ ESIs were retrospectively reviewed. Pain assessments as measured by visual analog scale (VAS) scores were recorded at baseline and 1-week and 3-month follow-ups. Results: Improvements in VAS scores at follow-ups compared with baseline were significant in both groups. No statistically significant differences were found between the two groups. Conclusion: Multiple ESIs prior to mild showed no benefit. A modified algorithm to perform mild immediately upon diagnosis or after the failure of the first ESI is recommended. Lay abstract Physicians use a structured decision-making process (an algorithm) to decide how best to treat lumbar spinal stenosis (LSS) that results from abnormal thickening of the spinal ligaments that run the length of the spinal cord. Early treatments can include one or more epidural steroid injections (ESIs). This study evaluated a change to the algorithm that involves earlier intervention with a minimally invasive, short outpatient procedure that removes a major root cause of the abnormal thickening (lumbar decompression) and leaves no implants behind. Records of patients treated with minimally-invasive lumbar decompression (mild(R)) after receiving either a single ESI procedure or none at all, were compared with the records of patients who underwent the mild procedure after receiving two or more ESIs (145 total patients). The patients' pain scores before surgery, at one week postsurgery and at three months postsurgery were reviewed. The improvements in pain scores following the mild procedure were compared within each group and between the two groups. The improvements in pain scores at both the one-week and three-month follow-up visits indicated that the mild procedure had a positive effect for both groups. Further, there were no significant differences in how much pain scores improved when the two groups were compared. Since neither group experienced significantly more pain relief than the other, there appears to be no benefit to having multiple ESI procedures before undergoing the mild procedure. The authors recommend that the algorithm be modified to perform the mild procedure either as soon as LSS is diagnosed or after the failure of the first ESI procedure.