OBJECTIVE Dynamic stabilization devices are designed to stabilize the spine while preserving some motion. However, there have been reports demonstrating limited motion at the instrumented level of the lumbar spine after @entity1344 ( @entity1344 ). The causes of this limited motion and its actual effects on outcomes after @entity1344 remain elusive. In this study, the authors investigate the incidence of unintended facet arthrodesis after @entity1344 and clinical outcomes. METHODS This retrospective study included 80 consecutive @entity1 with 1- or 2-level lumbar spinal stenosis who underwent laminectomy and @entity1344 . All medical records, radiological data, and clinical evaluations were analyzed. Imaging studies included pre- and postoperative radiographs, MR images, and CT scans. Clinical outcomes were measured by a visual analog scale (VAS) for back and leg @entity158 , the @entity717 Index (ODI), and Japanese Orthopaedic Association (JOA) scores. Furthermore, all @entity1 had undergone postoperative CT for the detection of unintended arthrodesis of the facets at the indexed level, and range of motion was measured on standing dynamic radiographs. RESULTS A total of 70 @entity1 (87.5%) with a mean age of 64.0 years completed the minimum 24-month postoperative follow-up (mean duration 29.9 months). Unintended facet arthrodesis at the @entity1344 instrumented level was demonstrated by CT in 38 (54.3%) of the 70 @entity1 . The mean age of @entity1 who had facet arthrodesis was 9.8 years greater than that of the @entity1 who did not (68.3 vs 58.5 years, p = 0.009). There were no significant differences in clinical outcomes, including @entity615 , ODI, and JOA scores between @entity1 with and without the unintended facet arthrodesis. Furthermore, those @entity1 older than 60 years were more likely to have unintended facet arthrodesis (OR 12.42) and immobile spinal segments (OR 2.96) after @entity1344 . Regardless of whether unintended facet arthrodesis was present or not, clinical evaluations demonstrated improvement in all @entity1 (all p < 0.05). CONCLUSIONS During the follow-up of more than 2 years, unintended facet arthrodesis was demonstrated in 54.3% of the @entity1 who underwent 1- or 2-level @entity1344 . Older @entity1 (age > 60 years) were more likely to have unintended facet arthrodesis and subsequent immobile spinal segments. However, unintended facet arthrodesis did not affect the clinical outcomes during the study period. Further evaluations are needed to clarify the actual significance of this phenomenon.

XXXX -related facet arthrodesis.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity615 :: ('MESH:D001416', 'Disease') :: ['VAS back and leg pain'] @entity158 :: ('MESH:D010146', 'Disease') :: ['pain'] @entity1344 :: ('MESH:D043171', 'Disease') :: ['DDS', 'Dynesys dynamic stabilization'] @entity717 :: ('MESH:D009069', 'Disease') :: ['Oswestry Disability']
@entity1344 :: (MESH:D043171,Disease) :: ['Dynesys dynamic stabilization']
