ASEPTIC LOOSENING AFTER CD INSTRUMENTATION IN THE TREATMENT OF SCOLIOSIS - A REPORT ABOUT 8 CASES

We report eight patients who had had operative treatment of idiopathic scoliosis with CD instrumentation and developed radiolucency around p edicle screws and a discharging sinus. There are two recent reports (D ubousset J, Shuffleberger H, Wenger D. Late infection with CD instrume ntation. Orthop Trans 18:121, 1994; Richards BS. Delayed infections fo llowing posterior spinal instrumentation for the treatment of idiopath ic scoliosis. J Bone Joint Surg [Am] 4:524-529, 1995) describing delay ed infection with spontaneous drainage after the treatment of scoliosi s with CD instrumentation and Texas Scottish Rite Hospital system with controversial results. Eight patients had radiologic signs of implant loosening after a mean of 7 months, with radiolucency around the pedi cle screws. Six patients developed a painful swelling and a dischargin g sinus after a mean of 21 months. Histopathologic results showed meta l wear and chronic inflammatory reaction with granuloma formation. No evidence of pyogenic infection was present. We believe that this compl ication is caused by micromotion.