title: Influence of alendronate and endplate degeneration to single level posterior lumbar spinal interbody fusion.
abstract: OBJECTIVE
  Using alendronate after spinal fusion is a controversial issue due to the inhibition of osteoclast mediated bone resorption. In addition, there are an increasing number of reports that the endplate degeneration influences the lumbar spinal fusion. The object of this retrospective controlled study was to evaluate how the endplate degeneration and the bisphosphonate medication influence the spinal fusion through radiographic evaluation.
  
  
  METHODS
  In this study, 44 patients who underwent single-level posterior lumbar interbody fusion (PLIF) using cage were examined from April 2007 to March 2009. All patients had been diagnosed as osteoporosis and would be recommended for alendronate medication. Endplate degeneration is categorized by the Modic changes. The solid fusion is defined if there was bridging bone between the vertebral bodies, either within or external to the cage on the plain X-ray and if there is less than 5° of angular difference in dynamic X-ray.
  
  
  RESULTS
  In alendronate group, fusion was achieved in 66.7% compared to 73.9% in control group (no medication). Alendronate did not influence the fusion rate of PLIF. However, there was the statistical difference of fusion rate between the endplate degeneration group and the group without endplate degeneration. A total of 52.4% of fusion rate was seen in the endplate degeneration group compared to 91.3% in the group without endplate degeneration. The endplate degeneration suppresses the fusion process of PLIF.
  
  
  CONCLUSIONS
  Alendronate does not influence the fusion process in osteoporotic patients. The endplate degeneration decreases the fusion rate.
authors.affiliation: Department of Neurosurgery, Seoul Nanoori Hospital, Seoul, Korea.
authors.forename: Sang-Mok
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Seoul Nanoori Hospital, Seoul, Korea.
authors.forename: Wootack
authors.initials: W
authors.lastname: Rhee
authors.affiliation: Department of Neurosurgery, Seoul Nanoori Hospital, Seoul, Korea.
authors.forename: Seongil
authors.initials: S
authors.lastname: Ha
authors.affiliation: Department of Neurosurgery, Seoul Nanoori Hospital, Seoul, Korea.
authors.forename: Jae Hyeon
authors.initials: JH
authors.lastname: Lim
authors.affiliation: Department of Neurosurgery, Seoul Nanoori Hospital, Seoul, Korea.
authors.forename: Il Tae
authors.initials: IT
authors.lastname: Jang
keywords: Alendronate; Endplate degeneration; Lumbar vertebrae; Osteoporosis; Spinal fusion