Pseudarthrosis after lumbar spinal fusion: the role of 18F-fluoride PET/CT

Abstract

PurposePainful pseudarthrosis is one of the most important indications for (revision) surgery after spinal fusion procedures. If pseudarthrosis is the source of recurrent pain it may require revision surgery. It is therefore of great clinical importance to ascertain if it is the source of such pain. The correlation between findings on conventional imaging (plain radiography and CT) and clinical well-being has been shown to be moderate. The goal of this study was to determine the possible role of 18F-fluoride PET in patients after lumbar spinal interbody fusion by investigating the relationship between PET/CT findings and clinical function and pain.MethodsA cohort of 36 patients was retrospectively included in the study after 18F-fluoride PET/CT for either persistent or recurrent low back pain (18 patients) or during routine postoperative investigation (18 patients) between 9 and 76 months and 11 and 14 months after posterior lumbar interbody fusion, respectively. Sixty minutes after intravenous injection of 156 – 263 MBq (mean 199 MBq, median 196 MBq) 18F-fluoride, PET and CT images were acquired using an integrated PET/CT scanner, followed by a diagnostic CT scan. Two observers independently scored the images. The number of bony bridges between vertebrae was scored on the CT images to quantify interbody fusion (0, 1 or 2). Vertebral endplate and intervertebral disc space uptake were evaluated visually as well as semiquantitatively following 18F-fluoride PET. Findings on PET and CT were correlated with clinical wellbeing as measured by validated questionnaires concerning general daily functioning (Oswestry Disability Index), pain (visual analogue scale) and general health status (EuroQol). Patients were divided into three categories based on these questionnaire scores.ResultsNo correlation was found between symptom severity and fusion status. However, 18F-fluoride activity in the vertebral endplates was significantly higher in patients in the lowest Oswestry Disability Index category (i.e. with the worst clinical performance) than in patients in higher categories (p = 0.01 between categories 1 and 2 and 1 and 3). The visual analogue scale and EuroQol results were similar although less pronounced, with only SUVmax between category 1 and 2 being significantly different (p = 0.04).ConclusionWe hypothesize that 18F-fluoride PET/CT may be able to provide support for the diagnosis of painful pseudarthrosis and could serve as a tool to discriminate between symptomatic and asymptomatic pseudarthrosis for revision surgery, as CT defines the consolidation status and PET pinpoints the ‘stress reaction’ at the vertebral endplates which significantly correlates with Oswestry Disability Index score.

Should Implant Breakage Be Always Considered as Implant “Failure” in Spine Surgery: Analysis of Two Cases and Literature Review

“…Also, there are various parameters defined on CT scan including extra-graft bridging bone and intra-graft bridging bone, but the results are inconsistent with other radiographic indicators and not reliable in all cases [9]. In the study published by Peters et al [10], they found a better technique for the diagnosis of pseudoarthrosis. They concluded that the 18 F-fluoride positron emission tomography (PET) scan has better accuracy compared to the CT scan in symptomatic patients, but in asymptomatic patients, CT scan is better.…”

Clinical and Radiological Features Predicting Intervertebral Autofusion after Successful Antibiotic Therapy in Pyogenic Vertebral Osteomyelitis

“…In addition, we believe that the degree of structural damage caused by PVO is greater than that observed in a benign fracture, which may account for the higher 18 F-FDG uptake in PVO. Increased 18 F-FDG uptake on the intervertebral structure is also correlated with the occurrence and magnitude of endplate subsidence [20]. Suto et al [21] reported that a higher 18 F-FDG uptake and ESR are related to the disease activity and severity of joint destruction in rheumatoid arthritis.…”

Novel Musculoskeletal and Orthopedic Applications of 18F-Sodium Fluoride PET

“…121 Spinal orthopedics is another area that may benefit from NaF-PET, which may have a role in predicting healing and identifying complications such as nonunion, pseudarthrosis, infection, and hardware loosening. [126][127][128][129][130][131] In pediatrics, Grant 27 reported utility in determining the cause of pain in children who underwent spinal fusion surgery for scoliosis. Fischer and colleagues 132 studied 20 patients who underwent cervical or lumbar intercorporal fusion and found that increased NaF activity could be visualized in cervical cages for up to 8 years after intervention and up to 10 years in lumbar cages (Fig.…”