Is the Fibronectin-Aggrecan Complex Present in Cervical Disk Disease?

ObjectiveTo investigate the presence of inflammatory cytokines and the fibronectin-aggrecan complex (FAC) in persons undergoing surgical treatment for cervical radiculopathy caused by disk herniation.DesignSingle-center, prospective, consecutive case series.SettingA single large academic institution.PatientsA total of 11 patients with radiculopathic pain and magnetic resonance imaging findings positive for disk herniation elected to undergo single-level cervical diskectomy.Methods or InterventionsLavage was performed by needle injection and aspiration upon entering the disk space for fluoroscopic localization before diskectomy.Main Outcome MeasurementsThe lavage fluid was assayed for pH and the FAC, as well as for the cytokines interleukin-6 (IL-6), interferon-γ, monocyte chemotactic protein (MCP), and macrophage inhibitory protein-1β.ResultsThe subjects were 7 women and 4 men with a mean age of 50.6 years (SE 9.7; range, 36-70 years). The mean concentrations (SE; range) in picograms per milliliter were 7.9 (4.4; 0-44) for IL-6, 25.3 (15.5; 0-159) for interferon-γ, 16.1 (11.9; 0-121) for MCP, and 6.1 (2.8; 0-29) for macrophage inhibitory protein-1β. The optical density of the FAC at 450 nm was 0.151 (0.036; 0.1-0.32), and the pH was 6.68 (0.1; 6.10-7.15). Statistically significant correlations were found between MCP and FAC (P = .036) and between FAC and pH (P = .008).ConclusionsBiochemical analysis of injured cervical intervertebral disks reveals the presence of inflammatory markers such as MCP, fragments of structural matrix proteins such as FAC, and a correlation with pH. Further evaluation of the FAC as a potential diagnostic biomarker or therapeutic target is warranted in the cervical spine.