title: SPECT/CT in differentiation of pseudarthrosis from other causes of back pain in lumbar spinal fusion: report on 10 consecutive cases.
abstract: OBJECTIVE
  SPECT fused with computed tomography (CT) provides a new approach for more accurate diagnosis of pseudathrosis after spinal fusion procedures. The aim of this study was to compare the findings of SPECT fused with CT (SPECT/CT) with those of CT alone for the diagnosis of pseudarthrosis.
  
  
  METHODS
  SPECT and CT of 10 consecutive patients with recurrence of back and/or leg pain and with suspicion of pseudarthrosis on conventional radiologic imaging were analyzed retrospectively. All had previously undergone anterior and/or posterior lumbar fusion techniques. Presence of screw loosening, nonunion through or around the cages, and facet joint degeneration were assessed for diagnosis of pseudarthrosis. Based on SPECT/CT scan findings, the decision of surgical reintervention was made on 6 of 10 patients. The clinical follow-up (mean, 15.6 months; range, 5-29 months) was evaluated according to Macnab criteria (excellent, good, fair, poor).
  
  
  RESULTS
  All patients showing screw loosening on CT alone showed also an abnormal uptake on SPECT/CT. SPECT/CT did not show abnormal uptake in 3 of 5 patients who had nonunion through/around the cages on CT alone. SPECT/CT was able to show increased uptake in 6 cases in which CT alone did not show facet joint degeneration.
  
  
  CONCLUSIONS
  In the lumbar spine, SPECT/CT seems to increase specificity for detection of nonunion of interbody devices compared with CT alone. It is more sensitive than CT to detect facet joint degeneration, and it can detect screw loosening as well as CT. These findings can be helpful for surgeons in planning appropriate surgical revision strategy.
authors.affiliation: Department of Nuclear Medicine, Geneva University Medical Center, Faculty of Medicine, University of Geneva, Geneva, Switzerland. olivier.rager@hcuge.ch
authors.forename: Olivier
authors.initials: O
authors.lastname: Rager
authors.forename: Karl
authors.initials: K
authors.lastname: Schaller
authors.forename: Michael
authors.initials: M
authors.lastname: Payer
authors.forename: David
authors.initials: D
authors.lastname: Tchernin
authors.forename: Osman
authors.initials: O
authors.lastname: Ratib
authors.forename: Enrico
authors.initials: E
authors.lastname: Tessitore
mesh_terms: D000328:Adult; D000368:Aged; D001416:Back Pain / Q000209:etiology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000150:complications; D007866:Leg; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011542:Pseudarthrosis / Q000150:complications* / Q000000981:diagnostic imaging* / Q000209:etiology; D012008:Recurrence; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome