title: Low-intensity pulsed ultrasound enhances healing of laminectomy chip bone grafts on spinal fusion: a model of posterolateral intertransverse fusion in rabbits.
abstract: BACKGROUND
  Laminectomy-derived chip bone graft was usually used in spinal fusion; however, the result of this kind of local bone used in lumbar posterolateral fusion is uncertain. This study tested the hypotheses that low-intensity pulsed ultrasound (LIPU) can accelerate the healing process of laminectomy bone chips in a spinal fusion and enhance the union rate.
  
  
  METHODS
  Forty-eight rabbits were randomly divided into three groups for the spinal unilateral uninstrumented posterolateral fusion of L5-L6: autologous iliac bone graft (AIBG), laminectomy chip bone graft (LCBG), LCBG plus LIPU (LCBG + LIPU). Each group was subdivided into 6-week and 12-week subgroups. All rabbits were subjected to radiographic examination and manual testing. All successful spinal fusion specimens received biomechanical testing and a histologic examination.
  
  
  RESULTS
  The LCBG + LIPU group had the highest successful fusion rate at 6-week and 12-week examination (75% and 100%, respectively). At 6 weeks, the average maximum toque at failure values of the fusion masses for the LCBG + LIPU group was significantly higher than that for the LCBG group (p = 0.034). The average maximum torque of the 12-week LCBG + LIPU group was significantly higher than those of the 12-week AIBG and 12-week LCBG groups (p = 0.040 and p = 0.026, respectively).
  
  
  CONCLUSIONS
  This study suggested that LIPU can enhance bone healing. With augmentation by LIPU, laminectomy chip bone used in lumbar posterolateral fusion can achieve a similar fusion rate and stronger fusion mass than those of an AIBG.
authors: Department of Orthopedics Surgery, Chang Gung Memorial Hospital, Chang Gung University, Kweishian, Taoyuan, Taiwan. jcl1265@adm.cgmh.org.tw
authors: Jen-Chung
authors: JC
authors: Liao
authors: Wen-Jer
authors: WJ
authors: Chen
authors: Lih-Hui
authors: LH
authors: Chen
authors: Po-Liang
authors: PL
authors: Lai
authors: Gun
authors: G
authors: Keorochana