Assessment of Vertebral Fracture Tuan Van Nguyen and
Assessment of Vertebral Fracture Tuan Van Nguyen and Nguyen Dinh Nguyen Bone and Mineral Research Program Garvan Institute of Medical Reseach Sydney, Australia Vietnam Osteoporosis Workshop, HCMC 2006
Vertebral fracture • The most common osteoporotic fracture • Patient’s and public health problem: – Increased risk of subsequent fractures – Quality of life: pain, disability – Increased morbidity and mortality risk – Costs Vietnam Osteoporosis Workshop, HCMC 2006
750, 000 Spine Fractures each year • Most common fragility fx • 5 -10% increase in all-cause mortality* • Acute or chronic back pain ~2/3 of the fractures are clinically silent • Height loss • Gastrointestinal / respiratory difficulties • Depression, loss of self-esteem • Impact on activities of daily living *Cooper C et al. Am J Epidemiol 1993; 137: 1001 -1005 Vietnam Osteoporosis Workshop, HCMC 2006
Prevalence of Vertebral fracture -Critically dependent on the criterion used. -Irrespective of the criterion used, prevalence of VD higher in men than in women: -25% vs 20% (3 SD) -17% vs 12% (4 SD) -27% vs 25% (25%) (Source: Jones G, Nguyen TV et al. , Osteoporos Int. 1996; 6: 233 -39) Vietnam Osteoporosis Workshop, HCMC 2006
Incidence of vertebral fracture Incidence (per 10, 000 person-years) of vertebral fracture (using Mc. Closkey-Kanis method), stratified by age and gender (Source: The EPOS Group, 2002) Vietnam Osteoporosis Workshop, HCMC 2006
Subsequent fracture (%/3 y) Association between prevalent vertebral fracture and subsequent fractures Prevalent vertebral fracture (Source: Delmas et al. BONE, 2003; 33: 522 -32. ) Vietnam Osteoporosis Workshop, HCMC 2006
Terminology Vertebral deformity/ Vertebral fracture Clinical vertebral fracture Asymptomatic Symptomatic • ∆ = imaging • Symptom Imaging diagnosis: X-ray, DXA, CT, MRI IOF recommends to report as “Vertebral fracture” Vietnam Osteoporosis Workshop, HCMC 2006
Endpoint for clinical trials • Trials of treatment of patients with existing vertebral fractures: – morphometric evidence of at least one baseline vertebral deformity – or the presence of at least one “definite” fracture according to SQ method. • Trials of primary or secondary prevention of vertebral fracture: may use QM or SQ or a combination. Vietnam Osteoporosis Workshop, HCMC 2006
Types of vertebral fracture Normal End-plate Concave Bi-concave Wedge fracture Compression fracture (crush) Vietnam Osteoporosis Workshop, HCMC 2006
Assessment of vertebral fracture Prevalent vertebral fracture • Semi-quantitative • Quantitative morphometry Incident vertebral fracture • Quantitative morphometry • Semi-quantitative • Algorithm-based qualitative Vietnam Osteoporosis Workshop, HCMC 2006
Approaches to the identification of vertebral fracture • Semi-quantitative method (SQ) or visual method • Quantitative vertebral morphometry (QM) – X-Ray – Lateral vertebral assessment (LVA): DXA • Algorithm-based qualitative assessment (ABQ) Vietnam Osteoporosis Workshop, HCMC 2006
Semi-quantitative grading (Genant et al 1993) Grade 0 Normal 1 (~20 -25%) Anterior Middle Mild fracture Posterior 2 (~25 -40%) Anterior Middle Moderate fracture Posterior 3 (~40%) Anterior Middle Severe fracture Posterior (Source: Genant HK et al, JBMR 1993; 8: 1137 -1148) Vietnam Osteoporosis Workshop, HCMC 2006
SQ: visual normal spine T spine Vietnam Osteoporosis Workshop, HCMC 2006 L spine
SQ Mild SQ Severe 3 1 1 3 Vietnam Osteoporosis Workshop, HCMC 2006
Morphometric measurements • Typically based on placement of 6 points that define: – the anterior height (Ha) – the middle height (Hm) – the central height (Hc) – and the posterior height (Hp) of the Vertebral body Vietnam Osteoporosis Workshop, HCMC 2006
MQ: types of measurement X-Ray (Standard but not “Gold standard”) Vietnam Osteoporosis Workshop, HCMC 2006 Lateral Vertebral Assessment (LVA): DXA
Electronic Cursor for Morphometry Vietnam Osteoporosis Workshop, HCMC 2006
MQ: Placement of six digitizing points for different projections of the vertebrae Vietnam Osteoporosis Workshop, HCMC 2006
QM with Six-Point Placements Vietnam Osteoporosis Workshop, HCMC 2006
Defining vertebral fracture Parameters: - Ha/Hp Hc Hpi (Hpi+1) Ha - Hc/Hp -Hpi/Hpi+1; Hpi/Hpi-1 Ha Hpi-1 Types of fracture: (Hpi) - Wedge: Ha, Ha/Hp - Biconcave (end-plate): Hc, Hc/Hp - Crush: Hpi/Hpi+1 or Hpi/Hpi-1 Vietnam Osteoporosis Workshop, HCMC 2006
Major contributions to quantitative morphometric assessments of Vert fx Reference Measurement Parameters calculated Fracture definition (Minne et al. , 1988) Ha, Hm, Hp Spine Deformity Index Below lower limit of normative values. Values are adjusted to the dimensions of the T 4> 2 SD from mean. (Kleerekoper et al. , 1984) Ha, Hm, Hp Wedge ratio, biconcave ratio, compress ratio. Any ratio 0. 85. Vertebral dimensions adjusted for specific level. (Gallagher et al. , 1988; Hedlund and Gallagher, 1988; Hedlund et al. , 1989) Hp, Width Wedge angle, PRH, PDAH, area Below lower limit of normative values. Values are adjusted to the dimensions of the T 4> 2 SD from mean. (Davies et al. , 1989; Davies et al. , 1993) Ha, Hp Wedge variable ( PRH), relative posterior height. Below 1 st decile above 10 th decile of normative value (Minne et al. , 1988); cutoff values adjusted to visual interpretation (Davies et al. , 1993). (Harrison et al. , 1990) Ha, Hm, Hp Wedge ratio, biconcave ratio, compress ratio. Any ratio 0. 75, mean height 15% less than adjacent vertebrae. (Raymakers et al. , 1990) Ha, Hm, Hp Spine Fracture Index 15% difference from expected value (Eastell et al. , 1991) Ha, Hm, Hp Wedge ratio, biconcave ratio, compress ratio. >3 SD and <4 SD from mean (grade 1); >4 SD from mean (grade 2). (Smith-Bindman et al. , 1991) Ha, Hm, Hp Index of Radiographic Area Adjusted height or area below 1 st percentile of normative values. (Black et al. , 1991) Ha, Hm, Hp Wedge ratio, biconcave ratio, compress ratio. Different cutoff values trim-curved normative data. (Ross et al. , 1993) Ha, Hm, Hp Height reduction. 3 SD below individually adjusted Z-scores. (Mc. Closkey et al. , 1993) Ha, Hm, Hp Predicted wedge, biconcave and posterior ratios. 3 SD below mean for two criteria PDAH, percent difference in anterior height between adjoining vertebrae; PRH, percent reduction of anterior to posterior height. Ha, anterior; Hm, Osteoporosis middle; and Hp, posterior height of each vertebral body from T 12 to L 4. Vietnam Workshop, HCMC 2006
QM: Eastell et al. 1991 Har Ha Hmr Hpr Type of fracture Hp Hm Wedge Compression Bi-concavity Degree of fracture H(a, m, p) – H(ar, mr, pr) SD(ar, mr, pr) Vietnam Osteoporosis Workshop, HCMC 2006 -4 SD< Grade 1 <-3 SD Grade 2 ≤ -4 SD
Lateral Vertebral Assessment (using DXA): Qualitative and quantitative Vietnam Osteoporosis Workshop, HCMC 2006
Six-point video-assisted Lateral Vertebral Assessment Vietnam Osteoporosis Workshop, HCMC 2006
Visual Assessment of Vertebral Fracture Using Lateral DXA Scan • VFA showed good sensitivity (>80%) in identifying moderate/severe XSQ deformities • Excellent negative predictive value (>90%) in distinguishing subjects without from those with vertebral deformities on a per subject basis. • Poor sensitivity to detect mild vertebral fractures, especially at the upper thoracic spine. (Source: J. Rea et al Osteoporos Int 2000) Vietnam Osteoporosis Workshop, HCMC 2006
Inter-agreement between expert readers (SQ) Visual XA (A) Visual XA (B) Visual MXA (A) Visual XA (B) 0. 86 - - Visual MXA (B) 0. 86 0. 87 0. 86 Visual XR, visual assessment of spinal radiographs Visual MXA, visual and quantitative assessment of MXA scan images (Source: Ferrar et al. JBMR 2003; 18: 933 -938) Vietnam Osteoporosis Workshop, HCMC 2006
Concordance between the three MQ and the SQ methods Criterion Kappa French Mixed European Argentinean Mean-3 SD cutoff 0. 73 0. 76 0. 73 0. 85 x mean cutoff 0. 78 0. 79 3 SD/PPH cutoff 0. 76 0. 73 0. 76 (Source: Szulc et al. BONE, 2003; 27: 841 -846) Vietnam Osteoporosis Workshop, HCMC 2006
SQ and MQ: A comparison Semi-quantitative (SQ) Quantitative or Morphometric approach Make use of the entire spectrum of visible features Obtain an objective and reproducible measurement Using expertises of Radiologists and Clinicians Using rigorous defined points placement and well-defined algorithms Quick performance Slower Identify more fracture Less More false-positive rate High sensitivity, lack of specificity Not complicated Complicated and tedious Widely applied in clinical practices Used in epidemiological studies or clinical trials Algorithm-based qualitative assessment (ABQ) Vietnam Osteoporosis Workshop, HCMC 2006
Algorithm-based qualitative (ABQ) approach • Differs from SQ method: – Focusing only on depression of the central endplate. – Introducing the concept of differential diagnosis of short vertebral height. • Reduce false positive rate Vietnam Osteoporosis Workshop, HCMC 2006
Depression of endplate? No Yes Close to centre of endplate? Short vert. height? No Yes Anterior location: step-like endplate in thoracic vertebrae (variant) Posterior location: Cupid’s bow or balloon disc in lumbar vertebrae No Check for oblique projection or scoliosis Yes Prior trauma, tumor, metabolic disease? No Yes Whole of endplate depressed within rim? Normal Scheuermann’s disease, childhood fracture, Scoliosis, variant in vert. body size Yes True depression? No Focused area: Schrnol’s nodes Yes Non-fracture deformity, developmental variant, non-osteoporotic fx or abnormal appearances due to other diseases or conditions Osteoporotic fracture. Workshop, HCMC 2006 Vietnam Osteoporosis Yes
Assessment of incident vertebral fracture • Semi-quantitative: has not been adequately studied • Quantitative Morphometry: – A new fracture: ≥ 15% reduction in any one of the three measured vertebral heights (Ha, Hm or Hp) – More stringent criteria: ≥ 20% change or a change > 3 SD of the mean differences (on repeated X-ray) for that vertebral level. • The best definition: has not been established Vietnam Osteoporosis Workshop, HCMC 2006
SQ Incident mild vertebral fx 0 Vietnam Osteoporosis Workshop, HCMC 2006 1
SQ Incident moderate Vert fx 0 Vietnam Osteoporosis Workshop, HCMC 2006 2
SQ Incident severe & moderate Fxs 1 3 0 Vietnam Osteoporosis Workshop, HCMC 2006 2
Summary • Assessment methods: – No “gold standard” for the identification – Three methods: SQ, QM and ABQ • Vertebral fracture: – Serious but mostly asymptomatic – Apprx. ¼ vertebral deformities are symptomatic Vietnam Osteoporosis Workshop, HCMC 2006
Lời Cảm tạ • Chúng tôi xin chân thành cám ơn Công ty Dược phẩm Bridge Healthcare, Australia là nhà tài trợ cho hội thảo. Vietnam Osteoporosis Workshop, HCMC 2006
Thank you! Vietnam Osteoporosis Workshop, HCMC 2006
Orthograde Vietnam Osteoporosis Workshop, HCMC 2006 Oblique
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