title: A novel approach for the annulus needle puncture model of intervertebral disc degeneration in rabbits.
abstract: OBJECTIVE
  To create the rabbit animal model of intervertebral disc (IVD) degeneration by the annulus needle puncture technique through a novel transabdominal approach.
  
  
  METHODS
  Thirteen New Zealand White rabbits underwent annular puncture at the L3/4, L4/5, and L5/6 discs through a transabdominal approach. For a longitudinal study to assess changes in disc height over time, serial X-rays, T2-weighted magnetic resonance imaging (MRI) (T2WI), and T2 mapping MRI were performed pre-operation and at 2, 4, and 6 weeks after puncture. Three rabbits were randomly selected for histological evaluation at 4 weeks post-operation. In addition, the remaining rabbits underwent a second surgery at 6 weeks after puncture.
  
  
  RESULTS
  All rabbits underwent the initial and second surgeries successfully without nerve-related complications. The operations had no significant effects on the rabbit body weight, and partial mild intra-abdominal adhesions were found in only 1 rabbit. The punctured discs were confirmed to be those of interest post-surgery and displayed progressive degeneration in disc height index (%), T2WI, and T2 relaxation time over time. At 4 weeks after puncture, a histological analysis revealed notochordal cell loss from the nucleus pulposus, fibrocartilage filling the nucleus pulposus space, and annulus fibrosus disorganization.
  
  
  CONCLUSIONS
  The annular needle puncture model established through a transabdominal approach, which demonstrates better visualization, exact identification, consistent degeneration degrees and minimal complications, is radiologically and histologically consistent with human IVD degeneration. T2 mapping MRI can quantitatively discriminate between grades of mild degeneration.
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital of Chongqing Medical University Chongqing 400016, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Lei
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital of Chongqing Medical University Chongqing 400016, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital of Chongqing Medical University Chongqing 400016, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital of Chongqing Medical University Chongqing 400016, China.
authors.forename: Xiaoji
authors.initials: X
authors.lastname: Luo
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital of Chongqing Medical University Chongqing 400016, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Tang
authors.affiliation: Department of Radiology, The First Affiliated Hospital of Chongqing Medical University Chongqing 400016, China.
authors.forename: Rongsheng
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital of Chongqing Medical University Chongqing 400016, China.
authors.forename: Chang
authors.initials: C
authors.lastname: Yu
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital of Chongqing Medical University Chongqing 400016, China.
authors.forename: Zhengxue
authors.initials: Z
authors.lastname: Quan
keywords: Animal model; T2 mapping; annular puncture; intervertebral disc degeneration; transabdominal approach