Radiological factors affecting functional outcome after the implantation of BDYN™ dynamic stabilization system for low-grade lumbar degenerative spondylolisthesis

•A retrospective non-randomized single center study was conducted over 5years, including 50 adults treated with BDYN™ dynamic stabilization system for low-grade lumbar degenerative spondylolisthesis; pre- and postoperative clinical and radiological evaluation were performed, with a mean follow-up of 24months, to determine radiological factors affecting functional outcomes and prognosis.•The BDYN™ system appears safe, well-tolerated, and could be an effective alternative to fusion techniques in the treatment of patients with low-grade lumbar degenerative spondylolisthesis while preserving motion and theoretically preserving the adjacent vertebral segment.•Clinically: 80% (40 patients) had a satisfying functional result in terms of daily life activity, pain and walking distance, and 20% (10 patients) were considered as having a poor outcome according to the ODI score.•Radiological findings: the loss of segmental lordosis, mainly due to the disc kyphosis at the level of the lumbar degenerative spondylolisthesis was statistically associated with bad functional outcomes (18° for ODI decrease>15 versus 11° for ODI decrease<15). There is also a tendency showing that a higher Pfirmann disc signal grade (grade IV) and a severe canal stenosis according to Schizas classification (grade C & D) are predictive of a poor result. The group of patients with bad outcome presented a higher grade of Pfirmann disc signal (grade IV) and a more severe canal stenosis (Schizas grade C and D).•A kyphotic disc at the level of the lumbar degenerative spondylolisthesis should be considered a contraindication for the implantation of such BDYN™ DS device. It seems that it is better to implant the BDYN™ in lumbar degenerative spondylolisthesis with mild or moderate disc degeneration and canal stenosis.•There are no radiological consequences of the device implantation on the static and the dynamic of the adjacent segments at two years postoperatively.