Cage Subsidence after Surgery on the Anterior Part of the Subaxial Cervical Spine: a Monocentric Prospective Clinical Study with a 3-Year Follow-Up

Abstract

The choice of an implant for vertebra body defect replacement in corpectomy for traumatic lesions remains a point of discussion among spinal surgeons. Nanostructured carbon cages are promising for use in spinal surgery.The purpose of this study was to determine the rate and degree of cage subsidence in the patients with traumatic lesions of the cervical spine undergone a single-level anterior corpectomy in the subaxial part of the cervical spine with reconstruction using a carbon or titanium cage. Materials and Methods. A prospective study included 47 patients undergone a single-level corpectomy of the cervical spine due to traumatic injury. Two groups were formed by adaptive randomization: group I with the patients with carbon cages (n = 23), and group II with the patients with titanium cages (n = 24). The evaluation of cages subsidence and stability was carried by X-rays and CT before and after surgery. The quality of life before and after the surgery was evaluated using NDI and VAS questionnaires.Results. According to the questionnaires, the absolute majority of the patients in both groups showed a statistically significant improvement of quality of life in the postoperative period (p<0.01). The first signs of implant subsidence were noted 3 months after surgery in group II. There were none of such cases in group I. The final result of the subsidence at the end of the follow-up comprised: for group I 0.6±0.4 mm, for group II 3.1±1.4 mm (p = 0.023). In group II, the bone block between bone tissue and the cage was recorded in 30% of patients (p = 0.037), in group I, the bone block was not formed. At the same time, according to the functional X-ray data, there were no signs of carbon cages instability in group I. None of the patients in groups I and II required revision surgery due to complications associated with cages placement.Conclusion. The outcomes of carbon nanostructure cages placement as bodyreplacing implants in the cervical spine were not inferior to the outcomes of titanium mesh cages using. In group I, the carbon cages subsidence was significantly lower than in group II with titanium cages. The bone block was not formed in the case of carbon cages. It is worth noting that the carbon structure of the cages allowed the radiological diagnostics of the operated segment without artifacts formation.