Percutaneous interspinous distraction device for the treatment of lumbar spinal canal stenosis: Clinical and radiographic results at 2-year follow-up

OBJECTIVE: To evaluate the effectiveness of the In- space (Synthes, Umkirch, Germany) and the correlation between radiographic parameters and clinical outcome in patients with lumbar spinal canal stenosis (LSS). METHODS: Between June 2009 and May 2013, 56 patients with LSS underwent In-space by one senior surgeon. All of the patients were evaluated both clinically and radiographic measurements before the procedure and each visit at the postoperative follow-up. Preoperative and postoperative X-ray imaging was performed before the procedure and at follow-up to assess the correlation with the clinical outcome. Radiological measurements and clinical outcomes were recorded to establish a relationship between the radiographic parameters and clinical outcome of this procedure. All patients had at least 2 years of follow-up. RESULTS: The mean VAS score of back pain decreased significantly (p < 0.05). CONCLUSIONS: Our data suggest that percutaneous interspinous devices are a good alternative to treat LSS. The device offers significant decrease in back pain, leg pain and ODI score with 2-year lasting relief from symptoms. The increased intervertebral foramenal space explains the improvement of leg pain, but the mechanism of back pain relief remains unclear. A very weak correlation between the radiographic changes and improvement of pain was found.