Interspinous spacers have recently been used in the treatment of lumbar spinal stenosis. In vitro studies have demonstrated a reduction in facet joint forces by 68% and annulus pressures by 63%. MRI studies have demonstrated increased canal and neural foraminal area after implantation of these devices. Previous studies by Zucherman et al. (Spine 30:1351-1358, 2005) demonstrated patient satisfaction rates of 71-73%.We carried out a multicentric retrospective study to assess the clinical outcomes following percutaneous posterior decompression using an interspinous spacer device (Aperius™-PercLID™ System; Kyphon-Medtronic). A total of 70 patients were included in the study. All of them had evidence of radiologically and clinically proven lumbar stenosis. The average age was 63.5 years. Patients completed the Zurich Claudication Questionnaire (ZCQ) and recorded pain levels on a Visual Analogue Scale (VAS). Average stay in hospital was 2 days. The average improvement in ZCQ included both symptomatic pain disappearance and functional ambulatory recovery. The average VAS pain score improved from 8.2 to 3.6 (scale of 1 to 10). The overall patient satisfaction rate was 76%. No complications were detected at 6 months' follow-up.