Minimally Invasive Treatment of Moderate Lumbar Spinal Stenosis with the Superion(®) Interspinous Spacer

PURPOSE: We evaluated the safety and effectiveness of the minimally invasive Superion(®) Interspinous Spacer (VertiFlex, Inc., San Clemente, CA) in patients with moderate LSS. METHODS: This single-arm prospective study enrolled 121 patients with moderate LSS between February 2008 and August 2009 and were followed up at 1 (n=111), 3 (n=96), 6 (n=81), and 12 (n=52) months. All patients were treated with the Superion Interspinous Spacer. Main outcomes were back function with the Oswestry Disability Index (ODI), extremity and axial pain severity with an 11-point scale, health-related quality of life with the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores from the SF-36, and adverse events through 12 months. RESULTS: ODI improved 64% (p<0.001) through 12 months and clinical success was 92%. Extremity and axial pain improved 53% and 49% (both p<0.001), respectively, through 12 months with clinical success of 76% for axial pain and 86% for extremity pain. Health-related quality of life improved 41% for PCS and 22% for MCS (both p<0.001) through 12 months. PCS clinical success was 81% and MCS clinical success was 62% at 12 months. Four (5.9%) explants were performed although 3 were unrelated to the device. Eight procedure-related adverse events, observed in 6 (5.0%) patients, included superficial incision seroma (n=5), minor wound pain (n=2), and infection (n=1). CONCLUSIONS: Preliminary results with the Superion Interspinous Spacer suggest that it is an effective and safe treatment option for patients with moderate LSS who are unresponsive to conservative care.