De novo spine surgery as a predictor of additional spine surgery at the same or distant spine regions

Introduction: Degenerative spine disorders are steadily increasing parallel to the aging of the population with considerable impact on cost and productivity. In this paper we study the prevalence and risk factors for multiple spine surgery and its impact on cost. Methods: Data on 1,153 spine surgery inpatients operated between October 2005 and September 2008 (index spine surgery) in regard to the number of previous spine surgeries and location of surgeries (cervical or lumbar) were retrospectively collected. Additionally, prospective follow-up over a period of 2-5 years was conducted. Results: Retrospectively, 365 (31.7%) patients were recurrent spine surgery patients while 788 (68.3%) were de novo spine surgery patients. Nearly half of those with previous spine surgery (51.5%) were on different regions of the spine. There were no significant differences in length of stay or hospital charges except in lumbar decompression and fusion (LDF) patients with multiple interventions on the same region of the spine. Significant differences (P<.05) in length of stay (5.4 days vs. 7.4 days) and hospital charges ($55,477 vs. $74,878) between LDF patients with one previous spine versus those with ≥3 previous spine surgeries on the same region were noted. Prospectively, the overall reoperation rate was 10.4%. The risk of additional spine surgery increased from 8.0% in patients with one previous spine surgery (index surgery) to 25.6% in patients with ≥4 previous spine surgeries on different regions of the spine (including index surgery). After excluding patients with previous spine surgeries on different regions of the spine, 17.2% of reoperated patients had additional spine surgery on a different spine region. The percentage of additional spine surgery on a distant spine region increased from 14.0% in patients with one spine surgery to 33.0% in patients with two spine surgeries on the same region. However, in patients with three or more spine surgeries on the same spine region there were no interventions on a distant spine region during the follow-up period. Conclusion: De novo spine surgery is associated with an increased incidence of additional spine surgery at the same or distant spine regions. Large prospective studies with extended follow-up periods and multifaceted cost-outcome analysis are needed to refine the appropriateness of spine surgery.