gms | German Medical Science

Treating lumbar segmental instability with various rigid fusion techniques is a common procedure. Despite obtaining bony fusion, the clinical outcome is not always satisfying. Compensatory loadsharing may result in progressive instability of neighbouring segments. Dynamic segmental restabilization is an alternative method. We report our experience using a dynamic system for segmental stabilization (DYNESYS^®). Clinical and radiological results have been evaluated.

In 4 years, 40 patients (female/male: 21/19) were treated by DYNESYS^® instrumentation for segmental restabilization (1/2/3/4 level(s): 22/14/3/1 case(s)). In special indications (8) an additional monosegmental interbody fusion (PLIF) was used in combined multilevel procedures. Other indications were: degenerative instability with stenosis (24); additional monosegmental spondylolisthesis (4); failed back surgery syndrome (4). Oswestry-low-back-pain and Kaneda-scores were used for clinical follow-up. Plain, flexion-extension X-rays, CT and/or MRI, and in some cases flexion-extension open MRI were employed for radiological evaluation.

According to clinical scores 33 patients had good or excellent outcomes; in 7 patients no benefit was achieved. In 3 cases malposition of pedicular screws caused poor outcome, in 1 case implant failure resulted in revision with PLIF procedure. In all other cases a permanent stabilization of segmental motion could be observed.

Dynamic transpedicular stabilization is a new competitive method of treatment for degenerative diseases of the lumbar spine. It provides immediate stabilization with controlled range of motion in hyper- or hypomobile degenerated segments. The clinical results are promising. Long-term follow-up is necessary.