Surgical outcomes of Cervios ChronOS cage implantation for degenerative cervical Intervertebral disk disorder

BACKGROUND:: Cervios ChronOS (CCOS) is a cervical cage containing artificial bone. To date, very few reports have documented the results of its clinical outcome. This study describes the outcomes of CCOS for anterior cervical discectomy with interbody fusion (ACD-IBF) in patients at the Chang Gung Memorial Hospital. MATERIALS AND METHODS:: Retrospectively reviewed 32 patients underwent ACD-IBF with 51 CCOS cages from 2007 to 2008. All patients had either intractable preoperative cervical radiculopathy or myelopathy for 3 months duration and underwent follow-up for >2 years.Postoperative outcomes were classified as favorable or unfavorable. Rigid bone fusion was defined as an interspinous distance ≤2 mm on dynamic lateral cervical radiographs and absence of radiolucent gaps between vertebral endplates and CCOS. Anterior disk height and interbody height were used for subsidence evaluation. RESULTS:: The postoperative outcomes were favorable in 86.7% and unfavorable in 13.3% of the patients. Two years after surgery, 90.01% had rigid bone fusion. The anterior disk height was increased at postoperative day 1 and month 3 (P<0.05), but gradually decreased to the preoperative height at sixth month (P>0.05). The interbody height did not change significantly throughout the follow-up. The segmental angle had significant lordosis at postoperative day 1 and month 3 (P<0.05), but kyphotic changes gradually restored the preoperative angle. The clinical outcome was significantly related to the rigid bone fusion rate (P=0.0186). Furthermore, smoking was a contributing factor to poor clinical outcome (P=0.035), and diabetes mellitus was a contributing factor to poor interbody fusion (P=0.009) CONCLUSIONS:: The CCOS cage can be safely and effectively used as a disk substitute after ACD-IBF. In diabetes mellitus patients, adjuvant-fixation instruments might improve postoperative bone fusion.