title: Dynamic Radiographic Results of Different Semi-Rigid Fusion Devices for Degenerative Lumbar Spondylolisthesis: "Dynamic Rod" vs. "Dynamic Screw Head".
abstract: OBJECTIVE
  To assess the clinical outcomes and compare the segmental range of motion (ROM) at the implanted L4-L5 level, the cranial and caudal adjacent levels, and the ROM of the whole lumbar spine after semi-rigid lumbar fusion with 2 different devices.
  
  
  METHODS
  Patients with neurogenic claudication, due to grade 1 spondylolisthesis and spinal stenosis at levels L4-L5, were treated either Bio-flex® (n = 28) and Cosmic® (n = 23); discectomy was not performed at any level. The clinical outcomes were compared between the 2 groups. All patients underwent neutral, flexion, and extension radiography before the surgery and after 2 years postoperatively. ROM was assessed at the level of L4-L5, L3-L4, L5-S1, and at the whole lumbar spine.
  
  
  RESULTS
  According to clinical outcomes, 82% and 78% of patients in the BioFlex and Cosmic groups, respectively, had a good or excellent result. In both groups, there was significant reduction of the segmental ROM at the implanted L4-L5 level (p = 0.039 and 0.011).
  
  
  CONCLUSIONS
  These outcomes may play a role in decreasing the risk of ASD after dynamic stabilization, at least 2 years after surgery.
authors.affiliation: Hallym University, College of Medicine, Spine Center, Chuncheon Sacred Heart Hospital, Department of Neurosurgery, Chuncheon, Korea.
authors.forename: Jin Seo
authors.initials: JS
authors.lastname: Yang
authors.forename: Yong Jun
authors.initials: YJ
authors.lastname: Cho
authors.forename: Suk Hyung
authors.initials: SH
authors.lastname: Kang
authors.forename: Hyuk Jai
authors.initials: HJ
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D001863:Bone Screws; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome