Two-year follow-up results of the Isobar TTL Semi-Rigid Rod System for the treatment of lumbar degenerative disease.

We retrospectively assessed the indications, safety and efficacy of a new dynamic stabilization system (the Isobar TTL Semi-Rigid Rod System, Scient'x, Bretonneux, France) for the treatment of lumbar degenerative disease in 37 consecutive patients (M:F=16:21, mean age 40.2 years) with lumbar degenerative disease who underwent surgery between June 2006 and May 2009. One patient was lost to follow-up. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS); range-of-motion (ROM) and disc height index (DHI) were assessed with radiography. Patients were followed for a mean of 24 months (range: 12-36 months). At the 3-month follow-up, there was significant improvement in VAS and ODI (p<0.05); at long-term follow-up VAS showed additional significant improvement (p<0.05) and ODI remained stable. At short-term follow-up, DHI was significantly restored (p<0.05) and ROM declined slightly (but not significantly); however, at long-term follow-up DHI was significantly reduced (p<0.05) compared to short-term follow-up and ROM was significantly decreased compared to the preoperative values (p<0.05). There were new signs of degeneration at adjacent levels in 14 patients (39%) on long-term follow-up MRI. Revision was required in three patients (8%) 24 months after the first operation due to adjacent segment disease. Screw loosening was observed in four patients (11%). The Isobar System after microsurgical decompression for lumbar degenerative disease provided excellent improvement in leg and back pain and patient satisfaction at late follow-up; however, evidence to suggest that Isobar outperforms traditional fusion is lacking. Larger studies of longer duration are warranted.