Eur Spine J. 2017 Apr 5. doi: 10.1007/s00586-017-5079-6. 

Porous silicon nitride spacers versus PEEK cages for anterior cervical discectomy and fusion: clinical and radiological results of a single-blinded randomized controlled trial.

Arts MP1, Wolfs JF2, Corbin TP3.

1 Department of Neurosurgery, Haaglanden Medical Center, PO Box 432, 2501 CK, The Hague, The Netherlands.
2 Department of Neurosurgery, Haaglanden Medical Center, PO Box 432, 2501 CK, The Hague, The Netherlands.
3 Corbin & Company, Maple Grove, MN, USA.




Anterior cervical discectomy with fusion is a common procedure for treating radicular arm pain. Polyetheretherketone (PEEK) plastic is a frequently used material in cages for interbody fusion. Silicon nitride is a new alternative with desirable bone compatibility and imaging characteristics. The aim of the present study is to compare silicon nitride implants with PEEK cages filled with autograft harvested from osteophytes.


The study is 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.


Anterior cervical discectomy and fusion; Herniated disc; PEEK; Randomized controlled trial; Silicon nitride

PMID: 28382392







In summary, this study demonstrated that patients with symptomatic herniated disc or spondylosis treated with anterior cervical discectomy and interbody fusion using silicon nitride or PEEK reported similar recovery rates. There were no significant differences in clinical outcomes at 24 months, although some intermediate measures were in favor of PEEK; but they did not reach the level of clinical relevance. Fusion rates of both implants improved over time and no significant differences were seen regarding fusion and subsidence. The study proved our primary hypothesis of similarity in NDI improvements between silicon nitride and PEEK.