title: Comparison of 2-Level Versus 1-Level Total Disc Replacement: Results From a Prospective FDA-Regulated Trial.
abstract: BACKGROUND
  Fusion has been the traditional surgery for painful disc degeneration unresponsive to nonoperative care. Fusion rates may decline in multilevel procedures. Also, fusion may force additional stress onto adjacent discs. This effect may be amplified in multilevel procedures. Single-level total disc replacement (TDR) has been found to be as effective as fusion. There have been few published reports addressing 2-level TDR. The purpose of this study was to compare results of TDR at 2 levels to 1-level procedures.
  
  
  METHODS
  This report included the first consecutive 86 patients who had reached 24-month follow-up from among those enrolled in the ProDisc-L investigational device exemption (IDE) study of patients undergoing TDR at 1 level (N = 54) or at 2 levels (N = 32). Clinical outcome measures included visual analog scales (VAS) assessing pain, Oswestry Disability Index, satisfaction measured by VAS, and responses to the question regarding whether the patient would have the same surgery again.
  
  
  RESULTS
  Operative time and length of hospitalization were significantly less in the 1-level cases compared to 2 levels (61.6 min vs 97.8 min; and 1.89 days vs 2.44 days; P < .05). There was a trend for less blood loss in single-level cases (59.0 mL vs 79.2 mL) (.05 < P < .09). VAS and Oswestry scores were significantly improved in both groups postoperatively (by approximately 50%). At no follow-up were there significant differences in VAS, Oswestry, or patient satisfaction scores between the single- and 2-level patients. At all follow-ups, the mean satisfaction in both groups was greater than 7.5 on a scale of 0 to 10.
  
  
  CONCLUSIONS
  Patients undergoing 2-level TDR improved significantly postoperatively based on VAS and Oswestry scores, and there were no significant differences in outcome scores when comparing 1- and 2-level TDR.
  
  
  CONCLUSIONS
  This study suggests that 2-level TDR can be undertaken in appropriately selected patients and achieve results similar to singlelevel cases.
authors: Texas Back Institute.
authors: Jack E
authors: JE
authors: Zigler
authors: Texas Back Institute Research Foundation, Plano, Texas.
authors: Donna D
authors: DD
authors: Ohnmeiss
keywords: ProDisc-L; Total disc replacement; clinical outcome; disc degeneration; lumbar spine