title: A universal pedicle screw and V-rod system for lumbar isthmic spondylolysis: a retrospective analysis of 21 cases.
abstract: OBJECTIVE
  To investigate the surgical outcome of a universal pedicle screw-V rod system and isthmic bone grafting for isthmic spondylolysis.
  
  
  METHODS
  Twenty-four patients with isthmic spondylolysis at L5 and grade 0-I spondylolisthesis (Meyerding classification) received isthmic bone graft and stabilization using the universal pedicle screw-V rod system. Back pain was evaluated using the visual analog scale (VAS) and time to bone healing, improvement in spondylolisthesis and intervertebral space height at L5/S1 and L4/L5 were assessed.
  
  
  RESULTS
  Twenty-one patients were followed up for 24 months and included in the analysis. Back pain was markedly improved at 3 months postoperatively with a statistical difference in VAS scores compared with preoperative VAS scores (P<0.001). The VAS scores were 0 to 3 at 6 months postoperatively in all patients and no back pain was reported in all patients except 2 patients who complained of back pain after prolonged sitting. X-ray examination showed a bone graft healing time of 3 to 12 months. Grade I spondylolisthesis improved to grade 0 in 4 patients and no noticeable change was observed in the remaining 17 cases. The intervertebral space height at L5/S1 was statistically increased (P<0.05) while no statistically significant change was seen at L4/L5. There was no statistically significant difference in the ROM of the intervertebral disks of L5/S1 and L4/5 before and after surgery.
  
  
  CONCLUSIONS
  The universal pedicle screw-V rod system and isthmic bone grafting directly repairs isthmic spondylolysis and reduces back pain, prevents anterior displacement of the diseased segment and maintains intervertebral space height, thus offering a promising alternative to current approaches for isthmic spondylolysis.
authors.affiliation: Department of Orthopedics, Shanghai Changzheng Hospital, Shanghai, China. chenxiongsheng@vip.sohu.com
authors.forename: Xiong-sheng
authors.initials: XS
authors.lastname: Chen
authors.forename: Sheng-yuan
authors.initials: SY
authors.lastname: Zhou
authors.forename: Lian-shun
authors.initials: LS
authors.lastname: Jia
authors.forename: Xiao-min
authors.initials: XM
authors.lastname: Gu
authors.forename: Lei
authors.initials: L
authors.lastname: Fang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhu
mesh_terms: D001416:Back Pain / Q000473:pathology; D001863:Bone Screws; D016025:Bone Transplantation / Q000379:methods*; D006801:Humans; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome