title: Evaluation of Decompression and Interlaminar Stabilization Compared with Decompression and Fusion for the Treatment of Lumbar Spinal Stenosis: 5-year Follow-up of a Prospective, Randomized, Controlled Trial.
abstract: BACKGROUND
  If nonoperative treatment for lumbar stenosis fails, surgery may be considered. This traditionally includes decompression often combined with fusion. Desire for less extensive surgery led to developing new techniques and implants, including an interlaminar device designed with the goal of providing segmental stability without fusion, following decompression. The purpose of this study was to investigate 5-year outcomes associated with an interlaminar device.
  
  
  METHODS
  This prospective, randomized, controlled trial was conducted at 21 centers. Patients with moderate to severe lumbar stenosis at one or two contiguous levels and up to Grade I spondylolisthesis were randomized (2:1 ratio) to decompression and interlaminar stabilization (D+ILS; n=215) using the coflex(®) Interlaminar Stabilization(®) device (Paradigm Spine, LLC) or decompression and fusion with pedicle screws (D+PS; n=107). Clinical evaluations were made preoperatively and at 6 weeks and 3, 6, 12, 18, 24, 36, 48, and 60 months postoperatively. Overall Food and Drug Administration success criteria required that a patient meet 4 criteria: 1) >15 point improvement in Oswestry Disability Index (ODI) score; 2) no reoperation, revision, removal, or supplemental fixation; 3) no major device-related complication; and 4) no epidural steroid injection after surgery.
  
  
  RESULTS
  At 5 years, 50.3% of D+ILS vs. 44% of D+PS patients (p>0.35) met the composite success criteria. Reoperation/revision rates were similar in the two groups (16.3% vs. 17.8%; p >0.90). Both groups had statistically significant improvement through 60 months in ODI scores with 80.6% of D+ILS patients and 73.2% of D+PS patients demonstrating >15 point improvement (p>0.30). VAS, SF-12, and ZCQ scores followed a similar pattern of maintained significant improvement throughout follow-up. On the SF-12 and ZCQ, D+ILS group scores were statistically significantly better during early follow-up compared to D+PS. In the D+ILS group, foraminal height, disc space height, and range of motion at the index level were maintained through 5 years.
  
  
  CONCLUSIONS
  Both treatment groups achieved and maintained statistically significant improvements on multiple outcome assessments throughout 5-year follow-up. On some clinical measures, there were statistically significant differences during early follow-up favoring D+ILS. At no point were there significant differences favoring D+PS. Results of this 5-year follow-up study demonstrate that decompression and interlaminar stabilization with coflex is a viable alternative to traditional decompression and fusion in the treatment of patients with moderate to severe stenosis at one or two lumbar levels.
  This is a Level I study. Institutional approval was received at each of the sites participating in the trial. Each patient gave informed consent to participate in the trial.
authors.affiliation: Department of Neurosurgery, NorthShore University HealthSystem, Evanston, IL.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Musacchio
authors.affiliation: NeuroTexas, Austin, TX.
authors.forename: Carl
authors.initials: C
authors.lastname: Lauryssen
authors.affiliation: Laser Spine Institute, Philadelphia, PA.
authors.forename: Reginald J
authors.initials: RJ
authors.lastname: Davis
authors.affiliation: The Spine Institute, Santa Monica, CA.
authors.forename: Hyun W
authors.initials: HW
authors.lastname: Bae
authors.affiliation: Texas Back Institute, Frisco, TX.
authors.forename: John H
authors.initials: JH
authors.lastname: Peloza
authors.affiliation: Texas Back Institute, Plano, TX.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Guyer
authors.affiliation: Texas Back Institute, Plano, TX.
authors.forename: Jack E
authors.initials: JE
authors.lastname: Zigler
authors.affiliation: Texas Back Institute Research Foundation, Plano, TX.
authors.forename: Donna D
authors.initials: DD
authors.lastname: Ohnmeiss
authors.affiliation: Senta Clinic, San Diego, CA.
authors.forename: Scott
authors.initials: S
authors.lastname: Leary
keywords: clinical outcome; decompression; instrumented fusion; interlaminar device; lumbar spine; randomized study; spinal stenosis