title: Comparative effectiveness of PEEK rods versus titanium alloy rods in lumbar fusion: a preliminary report.
abstract: BACKGROUND
  Posterior lumbar instruments made of titanium and its alloys could change the physiological distribution of load at the instrumented and adjacent segments, which is a main cause of implant failure, non-fusion and adjacent segment degeneration. Posterior lumbar rods made of polyetheretherketone (PEEK) which is a semirigid alternative to titanium and its alloys have been introduced in lumbar fusion. This prospective study compared the radiological and clinical outcomes of patients undergoing lumbar fusion with PEEK rods versus titanium alloy rods.
  
  
  METHODS
  Using transpedicular fixation and lumbar fusion, 21 patients were treated with titanium alloy rods (TI group), and 20 patients with PEEK rods (PEEK group). Radiological and clinical outcomes were evaluated, including the status of the implanted instruments, fusion rate, lumbar lordosis angle (LA), disc space height (DH), visual analog score (VAS) for lower back pain (VAS-BP) and leg pain (VAS-LP), Japanese Orthopedic Association scoring system (JOA score) and complications.
  
  
  RESULTS
  Clinical VAS-BP, VAS-LP and JOA scores were significantly improved at 3 months, 6 months, and 1 year postoperatively as compared with preoperative scores in both groups (p < 0.05), with similar levels of improvement observed at the same time points postoperatively between the two groups. The overall fusion rate was 100 % at the 1-year follow-up for both groups. No significant differences in lumbar lordosis angle were found preoperatively, 1 week and 1 year postoperatively in both groups (p > 0.05). The postoperative increase of disc space height and loss of disc space height during the follow-up showed a similar extent of change between both groups (p > 0.05).
  
  
  CONCLUSIONS
  PEEK rods offer a similar radiological and clinical efficacy as titanium alloy rods. PEEK rods, as a semirigid implant with unique characteristics, may be an effective alternative treatment for patients with degenerative lumbar disease in lumbar fusion.
authors.affiliation: Department of Spine Surgery, Qilu Hospital, Shandong University, No.107, Wenhua Xi Road, Jinan, Shandong, 250012, China. sssrql@163.com
authors.forename: Lei
authors.initials: L
authors.lastname: Qi
authors.forename: Mu
authors.initials: M
authors.lastname: Li
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhang
authors.forename: Jingsong
authors.initials: J
authors.lastname: Xue
authors.forename: Haipeng
authors.initials: H
authors.lastname: Si
mesh_terms: D000328:Adult; D000497:Alloys / Q000627:therapeutic use*; D001577:Benzophenones; D005260:Female; D006801:Humans; D007659:Ketones / Q000627:therapeutic use*; D017116:Low Back Pain / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000627:therapeutic use*; D011108:Polymers; D011183:Postoperative Complications / Q000517:prevention & control; D011446:Prospective Studies; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D014025:Titanium / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000497:Alloys; D001577:Benzophenones; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D014025:Titanium