title: Minimally invasive treatment of lumbar spinal stenosis with a novel interspinous spacer.
abstract: OBJECTIVE
  To assess the safety and effectiveness of a novel, minimally invasive interspinous spacer in patients with moderate lumbar spinal stenosis (LSS).
  
  
  METHODS
  A total of 53 patients (mean age, 70 ± 11 years; 45% female) with intermittent neurogenic claudication secondary to moderate LSS, confirmed on imaging studies, were treated with the Superion(®) Interspinous Spacer (VertiFlex, Inc, San Clemente, CA) and returned for follow-up visits at 6 weeks, 1 year, and 2 years. Study endpoints included axial and extremity pain severity with an 11-point numeric scale, Zurich Claudication Questionnaire (ZCQ), back function with the Oswestry Disability Index (ODI), health-related quality of life with the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores from the SF-12, and adverse events.
  
  
  RESULTS
  Axial and extremity pain each decreased 54% (both P < 0.001) over the 2-year follow-up period. ZCQ symptom severity scores improved 43% (P < 0.001) and ZCQ physical function improved 44% (P < 0.001) from pre-treatment to 2 years post-treatment. A statistically significant 50% improvement (P < 0.001) also was noted in back function. PCS and MCS each improved 40% (both P < 0.001) from pre-treatment to 2 years. Clinical success rates at 2 years were 83%-89% for ZCQ subscores, 75% for ODI, 78% for PCS, and 80% for MCS. No device infection, implant breakage, migration, or pull-out was observed, although two (3.8%) patients underwent explant with subsequent laminectomy.
  
  
  CONCLUSIONS
  Moderate LSS can be effectively treated with a minimally invasive interspinous spacer. This device is appropriate for select patients who have failed nonoperative treatment measures for LSS and meet strict anatomical criteria.
authors.affiliation: Spinal Care Unit, Sapir Medical Center, Kfar Saba, Israel.
authors.forename: Shay
authors.initials: S
authors.lastname: Shabat
authors.forename: Larry E
authors.initials: LE
authors.lastname: Miller
authors.forename: Jon E
authors.initials: JE
authors.lastname: Block
authors.forename: Reuven
authors.initials: R
authors.lastname: Gepstein
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017116:Low Back Pain / Q000601:surgery; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D010147:Pain Measurement; D011183:Postoperative Complications / Q000175:diagnosis; D011446:Prospective Studies; D019736:Prostheses and Implants; D011788:Quality of Life; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D013130:Spinal Stenosis / Q000601:surgery*