Short-term effects of minimally invasive dynamic neutralization system for the treatment of lumbar spinal stenosis: An observational study.

The aim of the study was to evaluate the safety and short-term effects of dynamic stabilization via minimally invasive system for degenerative lumbar spinal stenosis. Patients with degenerative lumbar spinal stenosis and treated with Transforaminal Lumbar Interbody Fusion via minimally invasive minimally system (mis-TLIF) were served as the control group.From April 2011 to March 2015, 47 patients (29 male, 18 female; mean age 47.6 [range, 26-52] years) with lumbar spinal stenosis were treated with decompression and excision of herniated disk via the minimally invasive system combined with the dynamic fixation technique, and 42 patients as control group with mis-TLIF. Minimally invasive surgeries were performed via the posterior incision approach. The clinical outcomes were evaluated by comparing the Visual Analog Scale (VAS) score, Oswestry Disability Index (ODI) scores, and the ROMs of the adjacent segment before and after surgery. The postoperative complications related to the implants were identified.A total of 83 patients (43 of Dynesys group and 40 of mis-TLIF group) were followed for an average duration of >35 months. Dynesys stabilization resulted in significantly higher preservation of motion at the index level (P < .05), and significantly less hypermobility at the adjacent segments. VAS for the back and leg pain and ODI improved significantly (P < .05) in 2 groups; however, there is no significant difference between the groups. In Dynesys group, 3 cases suffered skin flay necrosis, 1 of them had a wound infection that was treated with washing and drainage combined with antibiotic therapy. Skin flay necrosis were also observed in 2 cases of mis-TLIF group. Reoperation was performed in one case of Dynesys group for rupture of the internal fixation. No rupture of internal fixation was observed in mis-TLIF group.The nonfusion fixation system Dynesys may be used to treat degenerative spinal stenosis without posterior element damage. This surgical technique is safe and effective. However, utilizing higher preservation of motion may lead to the failure of internal fixation.