Cervical Arthroplasty in Patients above 45 Years: Clinical Results

Abstract

Introduction Cervical arthroplasty (CA) has been proposed for the treatment of cervical herniated disks and cervical spondylotic myelopathy. Opposing fusion, CA can preserve segmental motion and might prevent adjacent level disease. Doubts about these advantages in the treatment of older patients have restricted CA mainly for younger patients with well-preserved segmental function. The goal of this work is to evaluate the clinic and imagiologic results of this technique when applied to patients older than 45 years. Patients and Methods We prospectively studied a cohort of 101 consecutive patients submitted to CA (125 disk replacements), with an average follow-up of 31.2 months (maximum 56 months). Patients were assigned to one of two groups according their age (< 46 and > 45). An M6 (SpinalKinectics) prosthetic disk was used in all cases for the treatment of cervical radiculopathy, caused by soft or hard herniated disk, and for myelopathy due to anterior segmental spinal cord compression, as long as any segmental flexion/extension motion were still present. Exclusion criteria were: total absence of segmental motion, segmental instability/deformity, more than two adjacent level cervical stenosis, infection, rheumatoid diseases, cancer, chronic steroid use, or osteoporosis. Preoperative studies included flexion/extension X-ray and cervical CT or MRI. Patients were discharged within 24 hours after surgery. The dynamic X-rays were repeated at 6 and 12 months and every year after that and checked for signs of segmental fusion or adjacent level degeneration (ALD). The neurological status and the presence of axial and radicular pain (visual analogic scale and quantification of analgesic consumption) were also accessed. The statistical analysis was performed using EpiInfo7 software. Results We treated 47 patients younger than 46 years (46.5%) and 54 older than 45 (53.5%). The medium age was 48.2 ± 10.4 years (minimum 19–maximum 69). No other significant demographic differences between groups. No differences regarding follow-up complains of axial or radicular pain were found between both groups. A totally asymptomatic outcome at the last evaluation was achieved in 91.5% of the younger age cases comparing with 87.0% in the older ones (Fisher exact test p value = 0.537). The rate of unintentional fusion was 6.4% (8 segments out of the 125 treated), again with no statistical significance between both groups. New ALD were found in two cases (4.3%) of the younger and 3 (5.6%) of the older patients, (not statistically significant). Even in a subgroup analysis, the global results of patients with 60 or more years (13 patients) were not statistically different, comparing with the younger age group (< 46). One early postoperative prevertebral hematoma needed an emergent surgical drainage. No other surgical or prosthetic related complications were reported. No revision surgeries were performed. Conclusion Despite the general consensus and the fact that older patients tend to have a more advanced degenerative cervical spine status, cervical arthroplasty can still obtain the same excellent clinical result and segmental motion preservation, as for the younger patient population. The indication for a cervical arthroplasty should not be restricted by any age criteria but should rather take in account the dynamic status of the diseased segment.