2. Brox JI, Sørensen R, Friis A, et al. Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration. Spine (Phila Pa 1976) 2003 28:1913-21.
3. Fritzell P, Hägg O, Wessberg P. 2001 Volvo Award Winner in clinical studies: lumbar fusion versus nonsurgical treatment for chronic low back pain. Spine 2001 26:2521-4.
4. Hedlund R, Johansson C, Hägg O, et al. The long-term outcome of lumbar fusion in the Swedish lumbar spine study. Spine J 2016 16:579-87.
5. Yoshihara H, Yoneoka D. National trends in the surgical treatment for lumbar degenerative disc disease: United States, 2000 to 2009. Spine J 2015 15:265-71.
6. Norton RP, Bianco K, Klifto C, et al. Degenerative spondylolisthesis: an analysis of the nationwide inpatient sample database. Spine (Phila Pa 1976) 2015 40:1219-27.
7. Kuslich SD, Ulstrom CL, Griffith SL, et al. The Bagby and Kuslich method of lumbar interbody fusion. History, techniques, and 2-year follow-up results of a United States prospective, multicenter trial. Spine (Phila Pa 1976) 1998 23:1267-78.
8. Chou YC, Chen DC, Hsieh WA, et al. Efficacy of anterior cervical fusion: comparison of titanium cages, polyetheretherketone (PEEK) cages and autogenous bone grafts. J Clin Neurosci 2008 15:1240-5.
13. Kashii M, Kitaguchi K, Makino T, et al. Comparison in the same intervertebral space between titanium-coated and uncoated PEEK cages in lumbar interbody fusion surgery. J Orthop Sci 2019 Jul 30 [Epub]. pii: S0949-2658(19)30206-4.
https://doi.org/10.1016/j.jos.2019.07.004.
14. Lee DY, Jeong ST, Hong CH, et al. Risk factors of cage subsidence after posterior lumbar interbody fusion. J Korean Soc Spine Surg 2016 23:100-7.
15. Liu R, Xiao R, Tang Z, et al. Titanium cage versus polyetheretherketone cage in posterior lumbar interbody fusion with pedicle screw fixation. Chin J Tissue Eng Res 2015 19:6953-7.
17. Rickert M, Fleege C, Tarhan T, et al. Transforaminal lumbar interbody fusion using polyetheretherketone oblique cages with and without a titanium coating: a randomised clinical pilot study. Bone Joint J 2017 99-B:1366-72.
19. Tanida S, Fujibayashi S, Otsuki B, et al. Vertebral endplate cyst as a predictor of nonunion after lumbar interbody fusion: comparison of titanium and polyetheretherketone cages. Spine (Phila Pa 1976) 2016 41:E1216-22.
21. Moher D, Liberati A, Tetzlaff J, et al. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Int J Surg 2010 8:336-41.
22. Veritas Health Innovation. Covidence systematic review software. Melbourne (Australia): Veritas Health Innovation Melbourne; 2016.
23. Wells GA, Shea B, O’connell D, et al. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses [Internet] Ottawa (ON), Ottawa Hospital Research Institute. 2013 [cited 2020 Feb 5]. Available from:
http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp.
24. Duval S, Tweedie R. Trim and fill: a simple funnel-plot-based method of testing and adjusting for publication bias in meta-analysis. Biometrics 2000 56:455-63.
25. Schwarzer G. meta: an R package for meta-analysis. R News 2007 7:40-5.
26. Viechtbauer W. Conducting meta-analyses in R with the metafor package. J Stat Softw 2010 36:1-48.
27. Wrangel CV, Karakoyun A, Buchholz KM, et al. Fusion rates of intervertebral polyetheretherketone and titanium cages without bone grafting in posterior interbody lumbar fusion surgery for degenerative lumbar instability. J Neurol Surg A Cent Eur Neurosurg 2017 78:556-60.
28. EUROSPINE 2015 Copenhagen, Denmark, September 2-4: oral presentations. Eur Spine J 2015 24 Suppl 6:669-710.
29. Vilà Canet G, Isart Torruella A, Covaro A, et al. A comparative study to assess fusion rate differences between titanium and polyethereherketone (PEEK) cages in lumbar TLIF procedure. In: EUROSPINE 2014; 2014 Oct 1-3; Lyon, France. Uster-Zürich (Switzerland), EUROSPINE. 2014 Available from:
http://eposterlyon.eurospine.org/cm_data/eposter/P14.PDF.
31. Aono H, Takenaka S, Nagamoto Y, et al. Fusion rate and clinical outcomes in two-level posterior lumbar interbody fusion. World Neurosurg 2018 112:e473-8.
33. Han CM, Lee EJ, Kim HE, et al. The electron beam deposition of titanium on polyetheretherketone (PEEK) and the resulting enhanced biological properties. Biomaterials 2010 31:3465-70.
34. Yoon BJ, Xavier F, Walker BR, et al. Optimizing surface characteristics for cell adhesion and proliferation on titanium plasma spray coatings on polyetheretherketone. Spine J 2016 16:1238-43.
37. McGilvray KC, Waldorff EI, Easley J, et al. Evaluation of a polyetheretherketone (PEEK) titanium composite interbody spacer in an ovine lumbar interbody fusion model: biomechanical, microcomputed tomographic, and histologic analyses. Spine J 2017 17:1907-16.
38. Niu CC, Liao JC, Chen WJ, et al. Outcomes of interbody fusion cages used in 1 and 2-levels anterior cervical discectomy and fusion: titanium cages versus polyetheretherketone (PEEK) cages. J Spinal Disord Tech 2010 23:310-6.
40. Seaman S, Kerezoudis P, Bydon M, et al. Titanium vs. polyetheretherketone (PEEK) interbody fusion: meta-analysis and review of the literature. J Clin Neurosci 2017 44:23-9.
43. de Kunder SL, van Kuijk SMJ, Rijkers K, et al. Transforaminal lumbar interbody fusion (TLIF) versus posterior lumbar interbody fusion (PLIF) in lumbar spondylolisthesis: a systematic review and meta-analysis. Spine J 2017 17:1712-21.
45. Harris BM, Hilibrand AS, Savas PE, et al. Transforaminal lumbar interbody fusion: the effect of various instrumentation techniques on the flexibility of the lumbar spine. Spine (Phila Pa 1976) 2004 29:E65-70.
46. Rymarczuk GN, Harrop JS, Hilis A, et al. Should expandable TLIF cages be used routinely to increase lordosis? Clin Spine Surg 2017 30:47-9.