Low-back pain after lumbar fusion. Surgical and computed tomographic analysis.

Forty-eight patients with persistent pain after lumbar fusion were examined using computed tomography (CT). A total of 157 findings were observed, obviously with greatly varying significance. The main lesions were fragmentation of the fusion mass (16 patients), hair-line pseudarthrosis (9 patients), and spinal stenoses (8 patients). These were also the most frequent indications for reoperation in 20 patients. If the indication for reoperation was fragmentation, hair-line pseudarthrosis, or central spinal stenosis, the results were usually good during a follow-up period that ranged from 6 months to 4 years. At reoperation, 21 of 27 main lesions detected by CT were confirmed; six CT findings were partially or totally incorrect. However, we consider CT to be the best method for examining these problematic patients, but emphasize the choice of relevant CT diagnoses.