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

Peters M, Willems P, Weijers R, Wierts R, Jutten L, Urbach C, Arts C, van Rhijn L, Brans B - Eur. J. Nucl. Med. Mol. Imaging (2015)

Bottom Line: Patients were divided into three categories based on these questionnaire scores.However, (18)F-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).

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopedic Surgery, Maastricht University Medical Center, Postbox 5800, 6202 AZ, Maastricht, The Netherlands. marloes.peters@mumc.nl.

ABSTRACT

Purpose: Painful 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 (18)F-fluoride PET in patients after lumbar spinal interbody fusion by investigating the relationship between PET/CT findings and clinical function and pain.

Methods: A cohort of 36 patients was retrospectively included in the study after (18)F-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) (18)F-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 (18)F-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.

Results: No correlation was found between symptom severity and fusion status. However, (18)F-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).

Conclusion: We hypothesize that (18)F-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.

No MeSH data available.


Related in: MedlinePlus

Intervertebral bony fusion. Example of a bony bridge between the cage and the lower vertebra (closed arrow), but not between the cage and the upper vertebra (dotted arrow)
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Fig1: Intervertebral bony fusion. Example of a bony bridge between the cage and the lower vertebra (closed arrow), but not between the cage and the upper vertebra (dotted arrow)

Mentions: The 18F-fluoride PET/CT scans were evaluated by two independent blinded observers (M.P., B.B.) who determined a volume of interest (VOI) for 18F-fluoride uptake calculation and scored bony bridging based on the standard diagnostic CT scans. Afterwards, discrepancies between the observers were resolved by consensus. Scoring was verified by an orthopaedic surgeon (P.W.) and a musculoskeletal radiologist (R.W.). Interbody fusion between the upper and lower vertebrae was classified on the diagnostic CT scan as: the presence of a bony bridge (Fig. 1) on both sides either within or around the cages (score 2); the presence of a bony bridge on one side within or around a cage, right or left (score 1); or no bridging (score 0). Examples of these fusion scores are shown in Fig. 2. On each low-dose CT scan, three ellipsoid VOIs were manually drawn following the contours of the vertebrae (slice thickness 4 mm, short axis range 40 – 50 mm, long axis range 55 – 65 mm), including the intervertebral disc space and upper and lower endplates of the segment operated upon (Fig. 3a). These VOIs were then transferred to the coregistered attenuation-corrected PET image (Fig. 3b), and in each of these VOIs, the SUVmax was determined, i.e. activity in the upper, lower endplates and the intervertebral disc space (SUVmaxU, SUVmaxL and SUVmaxD, respectively), as well as the ratios of the upper and lower endplate activities to the intervertebral disc space activity (SUVratioU and SUVratioL, respectively).Fig. 1


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

Peters M, Willems P, Weijers R, Wierts R, Jutten L, Urbach C, Arts C, van Rhijn L, Brans B - Eur. J. Nucl. Med. Mol. Imaging (2015)

Intervertebral bony fusion. Example of a bony bridge between the cage and the lower vertebra (closed arrow), but not between the cage and the upper vertebra (dotted arrow)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4589546&req=5

Fig1: Intervertebral bony fusion. Example of a bony bridge between the cage and the lower vertebra (closed arrow), but not between the cage and the upper vertebra (dotted arrow)
Mentions: The 18F-fluoride PET/CT scans were evaluated by two independent blinded observers (M.P., B.B.) who determined a volume of interest (VOI) for 18F-fluoride uptake calculation and scored bony bridging based on the standard diagnostic CT scans. Afterwards, discrepancies between the observers were resolved by consensus. Scoring was verified by an orthopaedic surgeon (P.W.) and a musculoskeletal radiologist (R.W.). Interbody fusion between the upper and lower vertebrae was classified on the diagnostic CT scan as: the presence of a bony bridge (Fig. 1) on both sides either within or around the cages (score 2); the presence of a bony bridge on one side within or around a cage, right or left (score 1); or no bridging (score 0). Examples of these fusion scores are shown in Fig. 2. On each low-dose CT scan, three ellipsoid VOIs were manually drawn following the contours of the vertebrae (slice thickness 4 mm, short axis range 40 – 50 mm, long axis range 55 – 65 mm), including the intervertebral disc space and upper and lower endplates of the segment operated upon (Fig. 3a). These VOIs were then transferred to the coregistered attenuation-corrected PET image (Fig. 3b), and in each of these VOIs, the SUVmax was determined, i.e. activity in the upper, lower endplates and the intervertebral disc space (SUVmaxU, SUVmaxL and SUVmaxD, respectively), as well as the ratios of the upper and lower endplate activities to the intervertebral disc space activity (SUVratioU and SUVratioL, respectively).Fig. 1

Bottom Line: Patients were divided into three categories based on these questionnaire scores.However, (18)F-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).

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopedic Surgery, Maastricht University Medical Center, Postbox 5800, 6202 AZ, Maastricht, The Netherlands. marloes.peters@mumc.nl.

ABSTRACT

Purpose: Painful 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 (18)F-fluoride PET in patients after lumbar spinal interbody fusion by investigating the relationship between PET/CT findings and clinical function and pain.

Methods: A cohort of 36 patients was retrospectively included in the study after (18)F-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) (18)F-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 (18)F-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.

Results: No correlation was found between symptom severity and fusion status. However, (18)F-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).

Conclusion: We hypothesize that (18)F-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.

No MeSH data available.


Related in: MedlinePlus