gms | German Medical Science

Background: Anterior cervical discectomy (ACD) with interbody fusion cages is considered the standard surgical procedure in patients with cervical disc herniation. However, PEEK or metal cages have some undesirable imaging characteristics and a questionable use in infections. However, silicon nitride ceramic cages offer an effect for osteointegrative and anti-infective property. Whether patients treated with silicon nitride ceramic cages have similar functional outcome as patients treated with PEEK cages is not known. We present the design of the effectiveness of ceramic cages versus PEEK cages in patients with cervical disc herniation and/or osteophytes, and beside for cervical spondylodiszitis.

Materials and methods: Prospectively, we analyzed patients after anterior cervical discectomy with interbody fusion by PEEK cages and silicon nitride ceramic cages. All patients received a postoperative follow-up of 48 hours by plan X-ray films and CT-scans with functional X-rays films in motion after 6 weeks to judge fusion and the incidence of subsidence or instability. Clinical data were measured by visual analogue pain scale (VAS), SF-36 for quality of life after 3-6 months and Neck and Disability Index (NDI).

Results: First silicon nitride cages were implanted in July 2014. General follow-up was at least 3 months, which will be continued during the next 9 months. 25 patients were operated by three surgeons in the same manner because of cervical discal prolaps, cervical stenosis and even cervical spondylodiscitis. There were 8 one level ACDs, 9 patients with operated 2 levels, 6 three level cervical prolapses and even 2 patients suffering from segmental spondylodiscitis. In comparison, 20 patients were fused by PEEK cages after ACD by the same three surgeons. VAS, SF-36 and NDI was similar in both groups after 4 months follow-up, but fusion seems to be more effective after postoperative CT-scans and plan X-ray films in function in the silicon nitride group. Further, good fusion could be reached in patients with cervical spondylodiscitis without implant infection.

Conclusion: So far, silicon nitride cages offer a stable and faster fixation of vertebra bone due to direct in-growth of host bone into the textured implant surface. Implant failure and new clinical symptoms of pain was not demonstrated in both groups, but especially for spondylodiscitis this implant seems to be very effective in fusion and anti-infective in-growth.