Long-term clinical and radiographic outcomes of interlaminar coflex dynamic stabilization versus posterior lumbar interbody fusion for lumbar spinal stenosis: a comparative study with minimum 15-year follow-up

Abstract

This study aimed to evaluate the clinical and radiographic outcomes of inter-laminar Coflex dynamic stabilization compared with posterior lumbar interbody fusion (PLIF) for the treatment of lumbar spinal stenosis (LSS) over a long-term follow-up period exceeding 15 years. A retrospective cohort study was conducted on 78 patients (36 in the Coflex group and 42 in the PLIF group) treated between January 2007 and December 2009. Clinical outcomes were assessed using the visual analogue scale (VAS) for back and leg pain and the Oswestry Disability Index (ODI). Radiographic evaluation included intervertebral foraminal height (IFH), intervertebral space height (ISH), and range of motion (ROM) at the operative and adjacent levels. Complications, symptomatic adjacent segment disease (ASD), and revision rates were documented. At the final follow-up, the Coflex group demonstrated significantly lower low back VAS, leg VAS, and ODI scores compared to the PLIF group ( P < 0.05). Coflex initially maintained higher IFH and ISH at 1 month postoperatively ( P < 0.05), these parameters gradually decreased over time, becoming significantly lower than the PLIF group at the final follow-up ( P < 0.05). The Coflex group successfully preserved ROM at the operative level. In contrast, the PLIF group exhibited significantly increased ROM at both proximal and distal adjacent segments at the final follow-up ( P < 0.05). The incidence of symptomatic ASD (5.6% vs 16.7%) and the revision rate (2.8% vs 11.9%) were significantly lower in the Coflex group than in the PLIF group ( P < 0.05). Inter-laminar Coflex dynamic stabilization provides superior long-term clinical relief and functional improvement compared to PLIF for LSS patients. The progressive reduction in IFH and ISH in the Coflex group represents a biomechanical adaptive change that does not compromise long-term pain relief. By preserving operative segment mobility and preventing compensatory hypermobility at adjacent levels, Coflex significantly reduces the long-term risk of symptomatic ASD and the need for revision surgery.