The effect of spinal instrumentation particulate wear debris: an in vivo rabbit model and applied clinical study of retrieved instrumentation cases

• Published in: The spine journal 2003, Vol.3 (1), p.19-32
• Main Authors: Cunningham, Bryan W, Orbegoso, Carlos M, Dmitriev, Anton E, Hallab, Nadim J, Sefter, John C, Asdourian, Paul, McAfee, Paul C
• Format: Article
• Language: English
• Subjects: Acid Phosphatase - metabolism; Adult; Animal model; Animals; Apoptosis; Bone Remodeling; Cell Count; Cytokines; Cytokines - blood; Glycocalyx; Humans; Ilium - transplantation; Inflammation Mediators - blood; Male; Microscopy, Electron; Myelography; Orthopedic Fixation Devices - adverse effects; Osteoclasts - enzymology; Osteoclasts - pathology; Osteolysis; Phagocytosis; Posterolateral spinal fusion; Prosthesis Failure; Rabbits; Reoperation; Spinal Cord - diagnostic imaging; Spinal Cord - pathology; Spinal Cord - surgery; Stainless Steel; Time Factors; Titanium; Titanium and stainless steel particulate; Transplantation, Autologous; Tumor Necrosis Factor-alpha - metabolism; Twelve clinical cases
• ISSN: 1529-9430; 1878-1632
• DOI: 10.1016/S1529-9430(02)00443-6

Study design: The current study was undertaken to determine if the presence of spinal instrumentation wear particulate debris deleteriously influences early osseointegration of posterolateral bone graft or disrupts an established posterolateral fusion mass. Objectives: Using an in vivo animal model, the first phase (basic science) of this study was to evaluate the effect(s) of titanium wear particulate on a posterolateral spinal arthrodesis based on serological, histological and immunocytochemical analyses. The second phase (clinical) was to perform the same analysis of soft tissue surrounding spinal instrumentation in 12 symptomatic clinical patients. Summary of background data: The effect of unintended wear particulate resulting from micromotion between the interconnection mechanisms in spinal instrumentation remains a clinical concern. Methods: Thirty-four New Zealand White rabbits were randomized into two groups based on postoperative time periods of 2 months (Group 1, n=14) and 4 months (Group II, n=20). Group I underwent a posterolateral arthrodesis (PLF) at L5–L6 using tricortical iliac autograft or tricortical iliac autograft plus titanium particulate. Group 2 all received iliac autograft at the initial surgery and were reoperated on after 8 weeks and treated with PLF exposure alone or titanium particulate. Postoperative analysis included serological quantification of systemic cytokines. Postmortem microradiographic, immunocytochemical and histopathological assessment of the intertransverse fusion mass quantified the extent of osteolysis, local proinflammatory cytokines, osteoclasts and inflammatory infiltrates. Clinical aspect of study: Over the last 2 years, 12 patients more than 0.4 years after spinal instrumentation presented with painful paraspinal inflammation. At surgical exploration, the cultures were negative for infection and the surrounding soft tissue was examined for cytokine reactions. There was loosening of implants and osteolysis in the location of the wear debris in 8 of 12 patients. Results: Basic science phase: serological analysis of systemic cytokines indicated no significant differences in cytokine levels (p>.05) between the titanium or autograft treatments. Immunocytochemistry indicated increased levels of local cytokines: TNF-α at the titanium-treated PLF sites at both time periods (p