title: Effect of low-intensity pulsed ultrasound on posterolateral lumbar fusion of rabbit.
abstract: OBJECTIVE
  To observe the effect of low-intensity pulsed ultrasound in the posterolateral lumbar fusion of rabbit.
  
  
  METHODS
  A total of 48 New Zealand white rabbits were randomly divided into the observation group and control group, including the autogenous iliac observation group, artificial bone observation group, artificial bone control group and autogenous iliac control group according to the different bone grafting. The posterolateral lumbar fusion of rabbits in each group was analyzed and compared.
  
  
  RESULTS
  After 4 weeks of treatment using the low-intensity pulsed ultrasound, the fusion in the bone grafting area of observation group was good. There was the relatively dense fusion area between the right transverse process and artificial bone. The left transverse process had been completely fused, with the clear bone trabecula through the fusion area. There was no significant fusion sign in the control group. According to the fusion comparison between two groups, the fusion rate of the observation group was 83.3% and it was significantly higher than the one of the control group (37.5%). Results of the comparison were statistically significant (P<0.05). The number of chondrocytes and the increase in the relative gray-scale in the fusion area of the iliac observation group were significantly higher than ones of the iliac control group (P<0.05). The number of chondrocytes and the increase in the relative gray-scale in the fusion area of the artificial bone observation group were significantly higher than ones of the artificial bone control group (P<0.05). The expression of IL-1, IL-6 and IL-17 4 weeks after the treatment of the observation group was significantly lower than the one of the control group, with the statistical significance (P<0.05). It indicated that the treatment of low-intensity pulsed ultrasound could reduce the expression level of inflammatory factors.
  
  
  CONCLUSIONS
  The low-intensity pulsed ultrasound can significantly increase the bone grafting fusion rate of the rabbit's posterolateral lumbar fusion. The possible mechanism is that it promotes the lumbar posterolateral endochondral ossification and reduces the inflammatory reaction.
authors.affiliation: 3rd Department of Orthopedics, Rizhao People's Hospital Affiliated to Shandong University, Rizhao 276826, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: 3rd Department of Orthopedics, Rizhao People's Hospital Affiliated to Shandong University, Rizhao 276826, China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Li
authors.affiliation: 3rd Department of Orthopedics, Rizhao People's Hospital Affiliated to Shandong University, Rizhao 276826, China. Electronic address: chenleisd1969@126.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
keywords: Fusion; Ilium; Low–intensity pulsed ultrasound; Lumbar posterolateral