ASSESSMENT OF PSEUDOARTHROSIS IN PEDICLE SCREW FUSION - A PROSPECTIVE-STUDY COMPARING PLAIN RADIOGRAPHS, FLEXION EXTENSION RADIOGRAPHS, CT SCANNING, AND BONE-SCINTIGRAPHY WITH OPERATIVE FINDINGS/

Twenty-five consecutive patients who had previously undergone lumbar f usion using stainless steel pedicle screw instrumentation and complain ed of persistent, severe pain were identified for prospective study. A ll patients had been scheduled for hardware removal and fusion inspect ion. Studies to rule out pseudarthrosis included plain radiography, fl exion and extension radiography, computed tomography, and bone scintig raphy. Each preoperative radiographic study was then evaluated in a bl inded fashion by a single independent radiologist and was determined t o show fusion or pseudarthrosis. Each patient then underwent surgery, at which time the pedicle screw instrumentation was removed and the fu sion was inspected. Using surgical inspection as absolute evidence of fusion or pseudarthrosis, statistical analysis was undertaken to evalu ate the predictive value of the radiographic studies singly and in com bination. No statistically significant correlation was found.