title: ProDisc-L total disc replacement: a comparison of 1-level versus 2-level arthroplasty patients with a minimum 2-year follow-up.
abstract: METHODS
  This is a retrospective analysis of data that was collected prospectively from 2 concurrent FDA IDE lumbar arthroplasty clinical trials performed at a single center.
  
  
  OBJECTIVE
  To determine if there is a clinical difference between the 1-level ProDisc patients versus the 2-level ProDisc patients at a minimum of 2 years of follow-up.
  
  
  BACKGROUND
  Marnay's work with ProDisc I prompted the U.S. Clinical Trials of the ProDisc II under the direction of the FDA. Disc replacement surgery in the United States has shown promising results for all types of prostheses up to 6 months. Marnay and colleagues showed that their results at 10 years were still promising, and they saw no significant difference between 1-level and multilevel disc replacements. The findings of Ipsen and colleagues suggest that multilevel arthroplasty cases may be less successful than disc replacement at a single level.
  
  
  METHODS
  Patients were part of the FDA clinical trial for the Prodisc II versus circumferential fusion study at a single institution. We identified 27 patients who received ProDisc at 1 level and 32 who received it at 2 levels with at least a 2-year follow-up, for a total of 59 patients. Unpaired t tests were performed on the mean results of Visual Analog Scale, Oswestry Disability Index, SF-36 Healthy Survey Physical Component Summary, and satisfaction using 10-cm line visual scale scores to determine a clinical difference if any between the 2 populations.
  
  
  RESULTS
  While patients receiving ProDisc at 2 levels scored marginally lower in all evaluation indexes, score differences in each category were also found to hold no statistical significance.
  
  
  CONCLUSIONS
  This study was unable to identify a statistically significant difference in outcome between 1- and 2-level ProDisc arthroplasty patients in a cohort from a single center. The equality of clinical effectiveness between 1- and 2-level ProDisc has yet to be determined.
authors: Greater Pittsburgh Orthopaedic Associates, Pittsburgh, PA, USA. matthewhannibal@hotmail.com
authors: Matthew
authors: M
authors: Hannibal
authors: Derek J
authors: DJ
authors: Thomas
authors: Jeffrey
authors: J
authors: Low
authors: Ken Y
authors: KY
authors: Hsu
authors: James
authors: J
authors: Zucherman
mesh_terms: D000293:Adolescent; D000328:Adult; D001178:Arthroplasty / Q000379:methods; D019643:Arthroplasty, Replacement / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery*; D007405:Intervertebral Disc Displacement / Q000601:surgery; D007595:Joint Prosthesis; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D011446:Prospective Studies; D012189:Retrospective Studies