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Characteristics of Intradiscal Pressure change in graded destabilized Model
Poster Session 1/Spine. 14:45-15:45, Room 103 & Alley Area,
Poster 122
S603
Characteristics of Intradiscal Pressure change in graded destabilized Model. K. Kitahara1, K. Hasegawa2 and T. Hara3 Venture Business Laboratory, Niigata University, Niigata, Japan, 2 Niigata Spine Surgery Center, Niigata, Japan 3 Faculty of Engineering, Niigata University, Niigata, Japan
0.5
0
0
0
BF
PL D
ct
D SI
int a
PL D
D
BF
SI
in t ac t
SI
Fig.1 Mean moment and standard error bars (Nm). XXI ISB Congress, Poster Sessions, Wednesday 4 July 2007
250
250
250
200
200
150
150
150
100
100
100
50
50
50
0
0
0
䋪 䋪
200
䋪
PL D
0.5
2.0
䋪
BF
0.5
PL D
1.0
D
1.5
1.0
BF
1.5
1.0
int ac t
1.5
䋪
300
䋪
SI D
䋪
2.0
300 䋪
int act
2.5
䋪
2.0
300
PL D
䋪
䋪
Side bending
BF
䋪
Flexion 䋪
SI D
2.5
Extension
int ac t
㪊㪅㪇 䋪
䋪
䋪䋺p䋼0.05
Side bending
㪊㪅㪇
䋪
2.5 Moment (Nm)
Flexion
REFERENCES (1) Nachemson A. Lumbar intradiscal pressure. Acta Orthopaed Stand 1960;43: l-105. (2) Nachemson A. In vivo measurements of intradiscal pressure. J Bone Joint Surg [America] 1964;46:1077-1092. (3) Anderson BJ, Ortengren R, Nachemson AL, Elfstrom G, Broman H. The sitting posture: an electromyographic and discometric study. Orthoped Clin N Am 1975;6(1):105-120.
PL D
㪊㪅㪇
Extension
䋪
CONCLUSIONS Our study showed that the moment and the intradiscal pressure in extension and flexion were significantly affected by graded destabilize. However significant effect of graded destabilizations on the moment and the intradiscal pressure was not observed at side bending.
Standardized Pressure (%)
䋪䋺p䋼0.05
RESULTS AND DISCUSSION Fig.1 shows the value of the moment in extension, flexion and side bending. At extension, significant decreases in moment were observed after BF. At flexion, moment was decreased after SID, BF and PLD respectively. At side bending, significant decrease in moment was observed after PLD. Fig.2 shows intradiscal pressure. At extension, a significant increase in intradiscal pressure was observed after BF. At flexion, intradiscal pressure was decreased after BF significantly. Although no significant change in intradiscal pressure was observed at side bending. At extension and flexion, the moment and the intradiscal pressure were affected by graded destabilizations. BF had significant effect on the moment and the intradiscal pressure especially. It was guess that facet joint have a big role in extension and flexion. At side bending, significant change of the moment and the intradiscal pressure after graded destabilizations was not observed, besides the moment after PLD. It was suggested that the graded destabilizations had a small effect on the biomechanical behavior of side bending.
BF
METHODS The in vitro experiments were performed in a spinal motion tester with graded destabilized porcine lumbar spins. The specimens which considered of FSUs were dissected to remove all muscle and fatty tissues. The ligamentous tissues, discs and facet joints were left in place. Each specimen was tested in the intact and following the application of each of three graded destabilized model: Supraspinal and Interspinousligament Desmotomy, Bilateral Facetectomy, Posterior Longitudinal Ligament Desmotomy. A spinal motion tester was developed to apply displacement to the end plate of the cranial vertebra to simulate flexion-extension and side bending of the spine continuously. As the displacement was applied to the spine, angular motion of the segment was calculated based on the marker's location that was tracked with a CCD camera. A load transducer that measured force/torque components in six degree of freedom was mounted on the top of the specimen. Intradiscal pressure was measured to use of a pressure transducer that was inserted in nucleus pulposus from anterior-lateral (flexion-extension) and from anterior (side bending). The pressure transducer was barrel shaped with 1.6mm diameter and waterproofed to be able to measure the hydrostatic pressure of intervertebral disc in medical applications. Four cycles were performed for each
motion. Three cycles were applied to minimize the effect of the viscoelasticity of specimen. The intradiscal pressure and the moment were recorded during 4degree of flexion and extension to each side and 6degree of side bending to each side of the fourth cycle.
SI D
INTRODUCTION Measurements of pressure within the intervertebral disc provide important information on the biomechanical behavior of the intervertebral disc and spinal motion segments. The first measurement of intradiscal pressure was performed in cadaveric study of Nachemson.(1) Following these study, Nachemson measured intradiscal pressures in-vivo for various body postures and different lifting activities.(2)(3) The measured pressure was found to have a linear relation with the applied external loads and the intradiscal pressure slightly increased when the specimen was in flexion/extension, side bending and rotation. The objective of this study was to clarify intradiscal pressure change and spinal mobility during flexion-extension and side bending in graded destabilized porcine functional spinal units (FSUs).
int act
1
Fig.2 Mean rate of change of intradiscal pressure (%). Journal of Biomechanics 40(S2)
Poster 122
S603
Characteristics of Intradiscal Pressure change in graded destabilized Model. K. Kitahara1, K. Hasegawa2 and T. Hara3 Venture Business Laboratory, Niigata University, Niigata, Japan, 2 Niigata Spine Surgery Center, Niigata, Japan 3 Faculty of Engineering, Niigata University, Niigata, Japan
0.5
0
0
0
BF
PL D
ct
D SI
int a
PL D
D
BF
SI
in t ac t
SI
Fig.1 Mean moment and standard error bars (Nm). XXI ISB Congress, Poster Sessions, Wednesday 4 July 2007
250
250
250
200
200
150
150
150
100
100
100
50
50
50
0
0
0
䋪 䋪
200
䋪
PL D
0.5
2.0
䋪
BF
0.5
PL D
1.0
D
1.5
1.0
BF
1.5
1.0
int ac t
1.5
䋪
300
䋪
SI D
䋪
2.0
300 䋪
int act
2.5
䋪
2.0
300
PL D
䋪
䋪
Side bending
BF
䋪
Flexion 䋪
SI D
2.5
Extension
int ac t
㪊㪅㪇 䋪
䋪
䋪䋺p䋼0.05
Side bending
㪊㪅㪇
䋪
2.5 Moment (Nm)
Flexion
REFERENCES (1) Nachemson A. Lumbar intradiscal pressure. Acta Orthopaed Stand 1960;43: l-105. (2) Nachemson A. In vivo measurements of intradiscal pressure. J Bone Joint Surg [America] 1964;46:1077-1092. (3) Anderson BJ, Ortengren R, Nachemson AL, Elfstrom G, Broman H. The sitting posture: an electromyographic and discometric study. Orthoped Clin N Am 1975;6(1):105-120.
PL D
㪊㪅㪇
Extension
䋪
CONCLUSIONS Our study showed that the moment and the intradiscal pressure in extension and flexion were significantly affected by graded destabilize. However significant effect of graded destabilizations on the moment and the intradiscal pressure was not observed at side bending.
Standardized Pressure (%)
䋪䋺p䋼0.05
RESULTS AND DISCUSSION Fig.1 shows the value of the moment in extension, flexion and side bending. At extension, significant decreases in moment were observed after BF. At flexion, moment was decreased after SID, BF and PLD respectively. At side bending, significant decrease in moment was observed after PLD. Fig.2 shows intradiscal pressure. At extension, a significant increase in intradiscal pressure was observed after BF. At flexion, intradiscal pressure was decreased after BF significantly. Although no significant change in intradiscal pressure was observed at side bending. At extension and flexion, the moment and the intradiscal pressure were affected by graded destabilizations. BF had significant effect on the moment and the intradiscal pressure especially. It was guess that facet joint have a big role in extension and flexion. At side bending, significant change of the moment and the intradiscal pressure after graded destabilizations was not observed, besides the moment after PLD. It was suggested that the graded destabilizations had a small effect on the biomechanical behavior of side bending.
BF
METHODS The in vitro experiments were performed in a spinal motion tester with graded destabilized porcine lumbar spins. The specimens which considered of FSUs were dissected to remove all muscle and fatty tissues. The ligamentous tissues, discs and facet joints were left in place. Each specimen was tested in the intact and following the application of each of three graded destabilized model: Supraspinal and Interspinousligament Desmotomy, Bilateral Facetectomy, Posterior Longitudinal Ligament Desmotomy. A spinal motion tester was developed to apply displacement to the end plate of the cranial vertebra to simulate flexion-extension and side bending of the spine continuously. As the displacement was applied to the spine, angular motion of the segment was calculated based on the marker's location that was tracked with a CCD camera. A load transducer that measured force/torque components in six degree of freedom was mounted on the top of the specimen. Intradiscal pressure was measured to use of a pressure transducer that was inserted in nucleus pulposus from anterior-lateral (flexion-extension) and from anterior (side bending). The pressure transducer was barrel shaped with 1.6mm diameter and waterproofed to be able to measure the hydrostatic pressure of intervertebral disc in medical applications. Four cycles were performed for each
motion. Three cycles were applied to minimize the effect of the viscoelasticity of specimen. The intradiscal pressure and the moment were recorded during 4degree of flexion and extension to each side and 6degree of side bending to each side of the fourth cycle.
SI D
INTRODUCTION Measurements of pressure within the intervertebral disc provide important information on the biomechanical behavior of the intervertebral disc and spinal motion segments. The first measurement of intradiscal pressure was performed in cadaveric study of Nachemson.(1) Following these study, Nachemson measured intradiscal pressures in-vivo for various body postures and different lifting activities.(2)(3) The measured pressure was found to have a linear relation with the applied external loads and the intradiscal pressure slightly increased when the specimen was in flexion/extension, side bending and rotation. The objective of this study was to clarify intradiscal pressure change and spinal mobility during flexion-extension and side bending in graded destabilized porcine functional spinal units (FSUs).
int act
1
Fig.2 Mean rate of change of intradiscal pressure (%). Journal of Biomechanics 40(S2)