Ciments Acryliques N. Sahraoui

JV 2009 8h30-8h45 Ciments Acryliques N. Sahraoui

Transcript

1. ACTUALITES EN VERTEBROPLASTIE Comité Scientifique National du S.T.I.C. « Cyphoplastie par Ballonnets » du Ministère de la Santé 23 M A R S 2 0 0 9
2. ACTUALITES EN VERTEBROPLASTIE Comité Scientifique National du S.T.I.C. « Cyphoplastie par Ballonnets » du Ministère de la Santé 23 M A R S 2 0 0 9
3. ACTUALITES EN VERTEBROPLASTIE Comité Scientifique National du S.T.I.C. « Cyphoplastie par Ballonnets » du Ministère de la Santé 23 M A R S 2 0 0 9
4. Momomer release from PMMA bone cements during vertebroplasty Dr N. SAHRAOUI Dr C. LAVERGNE Dr C. Sender TEKNIMED
5. Propagation Initiation LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction Initiation LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction Propagation Initiation LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction Initiation LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction Propagation Initiation LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction Propagation Initiation LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction Propagation Initiation LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction Propagation LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..)
7. Initiation Act Init LIQUID phase + POWDER (MMA – DMPT - HQ) (PMMA beads – BPO – opacifier..) Polymerization reaction Propagation
8. Polymerization reaction
9. What about the MMA release
10. -II/ Cement thickness : less than thick ones thin specimens release MMA release depends of various factors: Monomer release - I/ Powder/liquid ratio (g/ml): 2.5 < P/L < 2 increased porosity longer curing time monomer release
11. - Start of cooling of bone cement practically no release - Mixing setting of bone cement Largest and most rapid release Monomer release
12. Residual MMA after curing ≅ 2-6 % Monomer release
13. 1st STUDY
14. P/L Spineplex (w/w) 1,5 KyphX (w/ w) 1,5 Osteopal V (w/w) 1,5 Opacity+ 1,5 Powder 20g 20g 26g 27.2g PMMA 11.7 54.6 49.5 MMA- styrene 56.8 68.0 BPO 1.5 2.0 0.4 0.5 BaSO4 30 30.0 ZrO2 45 45 HAP 5 Liquid 10ml 10ml 10ml 9.2ml MMA 97.4 99.1 97.9 99.0 DMPT 2.6 0.9 2.1 1.0 HQ 75ppm 75ppm 20ppm Method : simulated monomer release on 4 vertebroplasty bone cements Bone cement compositions
15. Determination of waiting time 40 Pa/s First step :Viscosity kinetics at 20°C / 45% RH with a Viscosafe rheometer from Anton Paar 1- Mixing for 1 minute 2-Tranfer into the sample container 3- Starting measurement 3min after onset of mixing 4- End at 2000 Pa.s viscosity Method
16. Second step :In vitro injection of PMMA 1- Injection of 4ml cement in a cancellous like foam immersed in water at 37°C; injection time corresponds to a viscosity of 40Pa.s 2- Sampling of 2ml from aqueous medium at 1, 3, 5, 10, 30 min, 1h and 1day after injection 3- Measurement of concentration of each sample by High Pressure Liquid Chromatography Method 37°
17. Two types of bone cement Results – Viscosity kinetics
18. Injection time at 4/5 and 11/12 min Results - Viscosity kinetics
19. Main release during mixing and doughing phases Vertebroplasty/arthroplasty: less MAA in circulating system in spine surgery Results – Monomer release 0 3.3750 6.7500 10.1250 13.5000 1min 3min 5min 10min 30min 1h 24h MMA (mg/mL cement) Time after injection OsteopalV Spineplex Opacity+ KyphX
20. Conclusions - Ajusting the composition of the powder phase, kinetics of viscosity can be controlled - Despite differences of composition, monomer release are quite similar for all tested vertebroplasty bone cements → Key parameter = visosity - Comparing verebroplasty to arthroplasty → Equivalent level of release but → Less MMA amount due to low volume injected
21. SOLUTION : Development of a cement with a higher initial viscosity limiting diffusion of MMA and a slow controlled kinetics of polymerisation permitting a longer injection period. How can we reduce monomer release ? - reducing mobility of the monomer, thus injecting a cement at a higher viscosity. Drawback : the injection window is decreased Perspectives
22. Viscosity Time No waiting time Short working time Long waiting time Short working time Short waiting time Long working time 40 Pa.s Confidence Classic bone cement V New generation bone cement Perspectives
23. (Williams, 1981) MMA toxicity -Release of monomer into blood during curing -Systemic effect on the lung ⇒ respiratory failure - liver and kidney - cardiovascular system ⇒ cardiac arrest, fall in blood pressure
28. Thank you For a better life, a better health…