Accuracy of bone SPECT/CT for identifying hardware loosening in patients who underwent lumbar fusion with pedicle screws

Abstract

Background The aim of this retrospective study was to evaluate the accuracy of bone SPECT (single photon emission computed tomography)/CT (computed tomography) in diagnosing loosening of fixation material in patients with recurrent or persistent back pain that underwent lumbar arthrodesis with pedicle screws using surgery and clinical follow-up as gold standard Methods A total of 48 patients (median age 49 years, range 21-81 years; 17 men) who had undergone lumbar spinal arthrodesis were included in this retrospective analysis. SPECT/ CT results were compared to the gold standard of surgical evaluation or clinical follow-up. Positive SPECT/CT results were considered true positives if findings were confirmed by surgery or if clinical and other examinations were completely consistent with the positive SPECT/CT finding. They were considered false positives if surgical evaluation did not find any loose pedicle screws or if symptoms subsided with non-surgical therapy. Negative SPECT/CT scans were considered true negatives if symptoms either improved without surgical intervention or remained stable over a minimum follow-up period of 6 months. Negative SPECT/CT scans were determined to be false negatives if surgery was still required and loosening of material was found.Results The median length of time from primary surgery to bone SPECT/CT referral was 29.5 months (range 12-192 months). Median follow-up was 18 months (range 6-57) for subjects who did not undergo surgery. Thirteen of the 48 patients were found to be positive for loosening on bone SPECT/CT. Surgical evaluation (8 patients) and clinical follow-up (5 patients) showed that bone SPECT/CT correctly predicted loosening in 9 of 13 patients, while it falsely diagnosed loosening in 4 patients. Of 35 negative bone SPECT/CT scans, 12 were surgically confirmed. In 18 patients, bone SPECT/CT revealed lesions that could provide an alternative explanation for the symptoms of pain (active facet degeneration in 14 patients, and disc and sacroiliac osteodegeneration in 7 patients and 1 patient, respectively). Overall sensitivity and specificity for the detection of loosening were 100 % and 89.7 %, respectively. The positive and negative predictive values were 69 % and 100 %, respectively. Conclusions This retrospective analysis suggests that bone SPECT/CT bone is a highly sensitive and specific tool for the exclusion of screw loosening in patients who present with recurrent low back pain after having undergone lumbar arthrodesis. In addition, it can identify other potential causes of recurrent low back pain in this patient population.

Value of standard radiographs, computed tomography, and magnetic resonance imaging of the lumbar spine in detection of intraoperatively confirmed pedicle screw loosening—a prospective clinical trial

“…3 implant loosening with better accuracy though practicality and radiation exposure is a concern [13,14]. MRI, with the advantage of avoiding ionizing radiation and better soft tissue visualization [15], is increasingly used in assessment of a patient with spinal disorders.…”

Impact of metal implants on xSPECT/CT Bone reconstruction: the “shining metal artefact”

“…We encountered this artefact in various sizes of metal implants and all anatomic regions. Increased radiotracer activity around metallic implants is a sign for loosening or infection and is often accompanied by lucencies on the CT part of the study (Hudyana et al, 2016 ; Murer et al, 2020 ; Romer et al, 2005 ). The “shining metal artefact” might be misdiagnosed for loosening or infection if the reader is not aware of its presence and typical manifestation.…”

Two decades of SPECT/CT – the coming of age of a technology: An updated review of literature evidence

“…In patients with chronic low back pain (LBP), SPECT/CT has been used to guide therapy [97][98][99] and to assess complications following spine surgery [100][101][102][103]. In patients with recurrent pain following lumbar arthrodesis, SPECT/CT was highly sensitive and specific for exclusion of screw loosening [102]. In pelvic girdle pain and sacroiliac joint (SIJ) dysfunction, SPECT/CT diagnosed SIJ incompetence with sensitivity of 95%, specificity of 99%, PPV of 99%, and NPV of 94% [104].…”