Cervical PEEK Cage
Common interbody graft options for anterior cervical discectomy and fusion(ACDF) include structural allograft and polyetheretherketone (PEEK). PEEK has gained popularity due to its radiolucency and its elastic modulus, which is similar to that of bone.
A study provided strong evidence that ACDF is effective treatment, but the overall rate of radiographic fusion with empty PEEK cages is slow and insufficient. Lack of complete radiographic fusion leads to less improvement of pain and disability. The study recommended against using empty uncoated pure PEEK cages in ACDF 1).
Studies comparing cervical titanium cages and PEEK cages are rare in the literature. Chou’s team retrospectively compared the results of anterior cervical fusion using titanium cages, PEEK cages and tricortical bone grafts 2). They noticed a better fusion rate and less subsidence in the PEEK cages group. However, the study only enrolled a small number of patients and cervical spinal function was not evaluated. In a systematic review by Kersten who compared a PEEK cage with a bone graft, titanium cage, and carbon fiber cage, no difference was found between PEEK and titanium cage 3).
A meta-analysis indicated no significant difference in functional and radiographic performance between the PEEK and titanium cages, although more subsidence occurred in the titanium cage group. More high-quality studies are needed to confirm these results to offer more information for the choice in clinical practice 4).
A study sought to compare the rates of pseudarthrosis, a lack of solid bone growth across the disc space, and the need for revision surgery with the use of grafts made of allogenic bone versus PEEK.
127 cases in which patients had undergone a 1-level ACDF followed by at least 1 year of radiographic follow-up. Data on age, sex, body mass index, tobacco use, pseudarthrosis, and the reoperation rate for pseudarthrosis were collected. These data were analyzed by performing a Pearson’s chi-squared test.
Of 127 patients, 56 had received PEEK implants and 71 had received allografts. Forty-six of the PEEK implants (82%) were stand-alone devices. There were no significant differences between the 2 treatment groups with respect to patient age, sex, or body mass index. Twenty-nine (52%) of 56 patients with PEEK implants demonstrated radiographic evidence of pseudarthrosis, compared to 7 (10%) of 71 patients with structural allografts (p < 0.001, OR 9.82; 95% CI 3.836-25.139). Seven patients with PEEK implants required reoperation for pseudarthrosis, compared to 1 patient with an allograft (p = 0.01, OR 10.00; 95% CI 1.192-83.884). There was no significant difference in tobacco use between the PEEK and allograft groups (p = 0.586).
The results of this study demonstrate that the use of PEEK devices in 1-level ACDF is associated with a significantly higher rate of radiographically demonstrated pseudarthrosis and need for revision surgery compared with the use of allografts. Surgeons should be aware of this when deciding on interbody graft options, and reimbursement policies should reflect these discrepancies 5).
The aim of a study is to compare silicon nitride implants with PEEK cages filled with autograft harvested from osteophytes.
A prospective, randomized, blinded study of 100 patients with 2 years follow-up. The primary outcome measure was improvement in the Neck Disability Index. Other outcome measures included SF-36, VAS arm pain, VAS neck pain, assessment of recovery, operative characteristics, complications, fusion and subsidence based on dynamic X-ray and CT scan.
There was no significant difference in NDI scores between the groups at 24 months follow-up. At 3 and 12 months the NDI scores were in favor of PEEK although the differences were not clinically relevant. On most follow-up moments there was no difference in VAS neck and VAS arm between both groups, and there was no statistically significant difference in patients’ perceived recovery during follow-up. Fusion rate and subsidence were similar for the two study arms and about 90% of the implants were fused at 24 months.
Patients treated with silicon nitride and PEEK reported similar recovery rates during follow-up. There was no significant difference in clinical outcome at 24 months. Fusion rates improved over time and are comparable between both groups 6).
Cages
Aves Cervical Bladed Peek Cage http://www.ledamed.com
AYERS ROCK Spineway France
CAP Cervical H.P.I. Medical France
CERAF ARCA-MEDICA Germany
cerv-X™
CERVICAL PEEK CAGE http://www.implantint.net/
CeSPACE® PEEK
Cervical PEEK cage Coroent http://www.goldengatevn.com/
Genoss Integral Cervical Cage™
LorX® Expandable Cervical Peek Cage with Blade
PROYSTER® Prodorth
Reborn® Cervical PEEK Cage http://www.meditechimplant.com
ROI-C cervical cage (LDR)
SAS 9® Biotechni France
SOURIRE ARCA-MEDICA Germany
Velofix http://www.youic.com/
Zero P (Synthes, Inc.)….
Case series
see Cervical PEEK Cage case series
References
1) Suess O, Schomaker M, Cabraja M, Danne M, Kombos T, Hanna M. Empty polyetheretherketone (PEEK) cages in anterior cervical diskectomy and fusion (ACDF) show slow radiographic fusion that reduces clinical improvement: results from the prospective multicenter “PIERCE-PEEK” study. Patient Saf Surg. 2017 Apr 28;11:12. doi: 10.1186/s13037-017-0128-y. eCollection 2017. PubMed PMID: 28465721; PubMed Central PMCID: PMC5410058.2) Chou YC, Chen DC, Hsieh WA, Chen WF, Yen PS, Harnod T, Chiou TL, Chang YL, Su CF, Lin SZ, Chen SY. Efficacy of anterior cervical fusion: comparison of titanium cages, polyetheretherketone (PEEK) cages and autogenous bone grafts. J Clin Neurosci. 2008 Nov;15(11):1240-5. doi: 10.1016/j.jocn.2007.05.016. Epub 2008 Sep 17. PubMed PMID: 18801658.3) Kersten RF, van Gaalen SM, de Gast A, Öner FC. Polyetheretherketone (PEEK) cages in cervical applications: a systematic review. Spine J. 2015 Jun 1;15(6):1446-60. doi: 10.1016/j.spinee.2013.08.030. Epub 2013 Dec 27. Review. PubMed PMID: 24374100.4) Li ZJ, Wang Y, Xu GJ, Tian P. Is PEEK cage better than titanium cage in anterior cervical discectomy and fusion surgery? A meta-analysis. BMC Musculoskelet Disord. 2016 Sep 1;17:379. doi: 10.1186/s12891-016-1234-1. PubMed PMID: 27585553; PubMed Central PMCID: PMC5009677.5) Fivefold higher rate of pseudarthrosis with polyetheretherketone interbody device than with structural allograft used for 1-level anterior cervical discectomy and fusion. J Neurosurg Spine. 2018 Oct 1:1-6. doi: 10.3171/2018.7.SPINE18531. [Epub ahead of print] PubMed PMID: 30485200.6) Arts MP, Wolfs JF, Corbin TP. Porous silicon nitride spacers versus PEEK cages for anterior cervical discectomy and fusion: clinical and radiological results of a single-blinded randomized controlled trial. Eur Spine J. 2017 Apr 5. doi: 10.1007/s00586-017-5079-6. [Epub ahead of print] PubMed PMID: 28382392.