Assessment of pseudarthrosis 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 fusion using stainless steel pedicle screw instrumentation and complained of persistent, severe pain were identified for prospective study. All patients had been scheduled for hardware removal and fusion inspection. Studies to rule out pseudarthrosis included plain radiography, flexion and extension radiography, computed tomography, and bone scintigraphy. Each preoperative radiographic study was then evaluated in a blinded fashion by a single independent radiologist and was determined to show fusion or pseudarthrosis. Each patient then underwent surgery, at which time the pedicle screw instrumentation was removed and the fusion was inspected. Using surgical inspection as absolute evidence of fusion or pseudarthrosis, statistical analysis was undertaken to evaluate the predictive value of the radiographic studies singly and in combination. No statistically significant correlation was found.