title: A comparison of patients who have undergone 1-Level versus 2-Level ProDisc arthroplasty: a prospective study with minimum of 5-year follow-up.
abstract: METHODS
  Analysis of data collected prospectively from the United States Food and Drug Administration Investigational Device Exemption (U.S. FDA IDE) clinical trial for patients who underwent ProDisc-L arthroplasty at 1- and 2- levels performed at 2 study centers.
  
  
  OBJECTIVE
  To determine if there is any clinical or radiographical differences between patients who received 1-level ProDisc-L and patients who received 2-level ProDisc-L with a minimum follow-up of 5 years.
  
  
  BACKGROUND
  Recent prospective U.S. FDA clinical trial results have been published showing efficacy of the ProDisc (DePuy Synthes, West Chester, PA) prosthesis in both single and 2 level surgical procedures. Results of these prospective randomized multicenter FDA IDE clinical trials showed safety, efficacy, and superiority over circumferential fusion.
  
  
  METHODS
  Patients were part of the FDA clinical trial for the ProDisc-L versus circumferential fusion study at 2 institutions. We identified 20 patients who received ProDisc-L at 1 level and 21 who received it at 2 levels for a total of 41 patients. Pre- and postoperative pain, clinical function, and range of motion were measured. An unpaired t test was done to compare the 2- versus 1-level disc replacement patients.
  
  
  RESULTS
  All patients had more than 60 months of clinical follow-up. The mean scores on the visual analogue scale were 37.1 and 28.7, respectively (P = 0.33) for 1- and 2-level patients. Oswestry Disability Index scores were 33 and 29.1, respectively for 1- and 2-level patients (P = 0.60); and SF-36 health survey physical scores were 43 and 43.9, respectively for 1- and 2-level patients (P = 0.81); SF-36 health survey mental scores were 46.2 and 46.6, respectively for 1- and 2-level patients (P = 0.923). The average final follow-up postoperative range of motion for 1- and 2-level total disc replacement was 6.0º and 5.4º, respectively (P = 0.632).
  
  
  CONCLUSIONS
  This study was unable to identify statistical differences in all clinical and radiographical outcomes for patients who underwent 1- and 2-level ProDisc arthroplasty in a cohort from 2 centers. Future studies with longer-term follow-up are needed to confirm these results.
  
  
  METHODS
  4.
authors: Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06511, USA. james.yue@yale.edu
authors: James
authors: J
authors: Yue
authors: Kai
authors: K
authors: Zhang
authors: Harrison X
authors: HX
authors: Bai
authors: Jerry
authors: J
authors: Du
authors: Frank
authors: F
authors: Cammisa
authors: Celeste
authors: C
authors: Abjornson
authors: Fred
authors: F
authors: Mo
mesh_terms: D000328:Adult; D001178:Arthroplasty / Q000379:methods*; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D010146:Pain / Q000503:physiopathology / Q000601:surgery; D010149:Postoperative Pain / Q000503:physiopathology; D057234:Preoperative Period; D011446:Prospective Studies; D011859:Radiography; D016032:Randomized Controlled Trials as Topic; D016059:Range of Motion, Articular / Q000502:physiology; D012447:Sacrum; D011795:Surveys and Questionnaires; D013997:Time Factors; D059145:Total Disc Replacement / Q000379:methods*; D016896:Treatment Outcome; D014481:United States; D014486:United States Food and Drug Administration; D055815:Young Adult