Bone SPECT of the back after lumbar surgery.

PURPOSE: It may be difficult to evaluate back pain in patients who have undergone spinal surgery, because symptoms may be secondary to all the possible abnormalities in patients who have not had surgery plus postoperative complications, including infection, unstable fusion sites, or transfer of biomechanical stresses to other regions.
MATERIALS AND METHODS: Sixty-three patients with back pain and a history of lumbar spinal surgery had bone SPECT examinations. Twenty-eight patients had laminectomies, 10 had laminectomies with fusion, 10 had laminectomies with fusion and metallic stabilization devices (3 of which were removed), 7 had fusion without laminectomy, 7 had discectomies, and 1 had a fusion with metallic stabilization but no laminectomy. Eighty-seven percent of the fusions were posterior. The results of SPECT scanning were correlated with surgery, clinical information, and diagnostic radiologic studies.
RESULTS: Patients with fusions tended to be scanned further out from the time of surgery than were patients with laminectomy alone or especially discectomy. Bone SPECT excluded bony abnormalities in the operative site in 7 of 63 patients. One hundred thirty-two lesions were uncovered, with facet abnormalities (n = 51) the most common followed by disc space-centered conditions (n = 29), pseudarthrosis (n = 20), sacroiliac joint (n = 18), vertebral body lesions (n = 9), and miscellaneous sites (n = 5). Sixty percent of the abnormalities located in the facets, disc spaces, and vertebral bodies were located in the operative field, whereas 29% were above and 11% were below it.
CONCLUSION: Bone SPECT was useful in evaluating these patients to exclude bony lesions or to identify pseudarthrosis, abnormal facets, disc space-centered lesions, and sacroilitis.