Scoliose-correctie
Prof.dr.ir. Bart Verkerke Dr. A.G. Veldhuizen
Dept of Biomedical Engineering
BMSA 1: Injury, repair, intervention and support
BMSA 2: Microbial adhesion and infection
Aim: To realize the development and application of advanced optical and biochemical diagnostic techniques for assessment of organ function, and the development of interventional strategies to assist, repair, or replace injured organs within translational setting.
Aim: To determine physico-chemical and biological mechanisms for the interaction of biological components with biomaterials surfaces to be applied for infection prevention by developing technology-based or tissueengineered solutions for the repair of human function.
Approach: -Development of diagnostic tools and markers -Design of mechanical organ support systems -Development of transplantation models -Performance of applied clinical research -Design and evaluation of interventional strategies -Product-driven research
Approach: -Study of mechanisms of biomaterial-related infections -Development and assessment of adhesion-modifying coatings -Study of molecular mechanisms of biofilm-formation -Study of biofilm architecture -Analysis of clinical biofilms -Prevention of biofilm formation
Normothermic liver machine perfusion for better preservation of organ function before transplantation. Organ function control is achieved by diagnostic markers/tools and by support systems
Heart assist devices can be used to bridge to transplantation, or to relieve the heart muscle and therewith allow it to recover
Confocal laser microscopic image of an ingrowing biofilm on a silicone rubber voice prosthesis (insert) isolated from a patient
Confocal laser microscopic image of an E. coli biofilm on a monofilament surgical polypropylene mesh (insert) for abdominal wall reconstruction
BMSA 3: Permanent implants for function restoration
BMSA 4: Tissue engineering and scaffold materials
Aim: To realise and test permanent implants and diagnostic instruments for the repair of human function.
Aim: To realise new strategies for the repair of human tissues and organs based on (biodegradable) polymers and/or humoral factors and (stem)cells.
Approach: -Design of innovative implants -Realization of prototypes of innovative implants -Exploration of potential use of hybrid implants -Design of diagnostic tools / instruments -Development of algorithms for analysing complex images
Approach: -Study of cell-scaffold interactions -Isolation,expansion, differentiation of autologous (stem/progenitor) cells -Design of innovative, smart, degradable scaffolds -Study of mechanisms of tissue repair (inflammatory niche) -Implementation of modulation of inflammation for repair -Induction of stem cell homing and angiogenesis -Development of a cell-based implantable kidney -Focus on cardiovascular, renal, bone/cartilage applications
Application of memory metal as a scoliosis correction device. Scoliosis can be detected by image analysis algorithms
Examples of innovative implant design: the Groningen temporomandibular joint prosthesis and a voice-producing prosthesis for laryngectomised patients (insert)
Design of a degradable polyurethane scaffold material with interconnected pores, and the tissue response to the degrading scaffold (insert)
Clinical evaluation of the tissue response to implants – lens epithelial cells responding to the presence of an accommodating intra-ocular lens
Scoliose
Scoliose
Scoliose-correctie
Hippocrates (400 BC)
Scoliose-correctie
Scoliose-correctie
Milwaukee brace
Boston brace
Scoliose-correctie
Luque systeem
Harrington methode
Cotrel-Dubousset systeem
Ontstaan van scoliose
A vd Plaats
Ontstaan van scoliose 3
0,15 Ux
2
Uy
0,1
Uz Rotx 1
Roty
0,05
Rotz
0
-1
-0,05
-2
-0,1
-3
-0,15
-4
Rotation [rad]
Displacement [mm]
0
-0,2 Sacr
L5
L4
L3
L2
L1
T12
T11
T10
eis: koppeling van laterale verplaatsing en axiale rotatie A vd Plaats
T9
T8
T7
T6
T5
T4
T3
T2
T1
alleen als asymmetrie in: ligamentum flavum en intertransversale ligament
Progressie van scoliose
• achterblijvende groei spieren + ligamenten • visco-elastisch gedrag discus, ligamenten
G Nijenbanning, DJ Wever
Progressie van scoliose
in FEM geen mm rotatores, mm multifidus, facetgewrichten; discus als balkelement
G Nijenbanning
Ontstaan, progressie van scoliose • numeriek rigid body model • initiatie: symm én asymm achterblijven in groei van spieren en ligamenten • progressie afhankelijk van rek in spieren en ligamenten echter: discus als bolscharnier; geen facetgewrichten; spieren en ligamenten identiek
LLJ Kamman
Progressie van scoliose
ontstaan door stoornis in evenwichtssysteem
J Cheung
voorspelling progressie adhv spinale groei en EMG-ratio
Virtuele scoliose-chirurgie • • • •
optimalisatie braces optimalisatie implantaten ontstaan van scoliose progressie van scoliose
operatiestrategie
chirurgisch resultaat
X-ray / echo digitalisatie bepaling stijfheid
wervelkolom geometrie Numeriek model
gebruikersinterface grafische representatie expert-systeem feedback
Numeriek model
Model of motion segment Body-disc-body: • Based on concave endplates • Vertebrae: rigid bodies • Intervertebral disc: annulus and nucleus
Geometry: Panjabi et al.
Model of motion segment Intervertebral disc: Annulus fibrosus • 2 layers of fibers (double mesh) +/-30 degrees with local x-axis • Volume fraction 16% Nucleus Pulposus • Incompressible fluid
Model of motion segment
Validation body-disc-body with literature: • High range in measured stiffness. • Overall mechanical behavior corresponds well. • Model is stiff in lateral bending. = model. *=measured
in Thoracic region.
Model of motion segment Facet joints: • Modeled as surfaces with cartilage in between, with low shear and tension resistance. • Facet angles determine restricted motions. • Results: Increase of stressstiffening (non-linear) behavior in flexion, extension and AP-shear. Geometry: Panjabi et al.
Model of motion segment
Ligaments: • Bilinear load-deformation curves: constant throughout spine. • Tension only. • 6 ligaments (Lumbar).
Measurements: Chazal et al.
Sensitivity analysis Growth
Interpersonal differences
height
+3%
±60%
depth
+20%
±6%
width
+10%
±5%
Growth
Interpersonal differences
height depth width height depth
width
axial compression
-3%
+19% +6% ±66%
±6%
±3%
flexion
-3%
+69% +10% ±54% ±21%
±5%
extension
-3%
+66% +8% ±58% ±20%
±4%
lateral bending
-3%
+21% +33% ±56%
±17%
torsion
-3%
+43% +23% ±55% ±13% ±12%
±6%
Sensitivity analysis Geometry of disc and vertebrae have large influence on stiffness ⇒ Growth has influence ⇒ Patient specific data has to be accurate
• Relative size influence
(30-50%)
of nucleus has little
⇒ No patient-specific data required.
Model of motion segment Influence ligaments & facet joints
Lumbar model
Level-specific: • Geometry vertebra (processes) and disc. • Wedge angle of vertebrae. • Facet angles (averaged for left and right).
Lumbar model
• •
Validation with literature: stiffness in flexion too high. Theoretical stiffness lumbar level: ¼ of motion segment . NOT in measurements: protocol or specimen differences? => Measurements with same specimen (Iris).
Numeriek model
Motion segment with facet joints in response to extension loading. The contours represent the Von Mises stresses, in N/mm2.
Numeriek model
Stijfheidsmeting
I Busscher (ism dr Veldhuizen, Orthopedie; prof van Dieën, VUmc)
3D visualisatie
3D visualisatie X-Rays
3D CT Spine Template
Individual 3D CT Spine
TA Sardjono, KE Purnama
2D US Spine
Automatische detectie Cobb-hoek
Scannen met ultrageluid
Scannen met ultrageluid
axial
sagittal
coronal
Scannen met ultrageluid
Scannen met ultrageluid
Scoliose-correctie Vormgestuurd vs Krachtgestuurd, gebruikmakend van visco-elasticiteit
Memory metal
Memory metal
Scoliose-correctie
TriaC brace Baat Engineering, Somas, Boston Brace
G Nijenbanning
Scoliose-correctie
geheugenmetalen correctiesysteem DePuy-Spine
MM Sanders, DJ Wever
Non-fusie scoliose-correctie Voordeel: • Eerder ingrijpen, want groei is mogelijk • Geen fusie
BMT - De kunst van het beter maken
