P8. Correlations between sagittal plane disc dimensions and principal surface strains across the L3-4 intact IVD during in vitro multidirectional loading

ABSTRACTCervical muscles are crucial in providing the stability of the cervical spine. Many in vitro studies have investigated the relationship between muscle force and stability directly. However, the effects of different muscle dysfunctions or muscle recruitments on cervical spine stability are not yet clear and therefore, worthy of study. A spine testing apparatus with muscle force replication activated by pneumatic cylinders was developed to find the effect of muscles on spinal stability. Seven porcine cervical spines (C2-T1) were used. Three pairs of cervical muscles, including neck flexors (sternocleidomastoid, SCM) and neck extensors (splenius capitis, SPL; semispinalis capitis, SSC), were simulated. The experimental tests included: 1. no muscle recruitment, 2. full muscle recruitments, 3. SCM dysfunction, 4. SPL dysfunction, and 5. SSC dysfunction. The external pure moment in sagittal plane was applied from 0 Nm to 2 Nm to examine the stability/flexibility of specimens. The spinal stability was evaluated by the neutral zone (NZ), the range of motion (ROM), the reduced NZ (R_NZ), and the reduced ROM (R_ROM). Loading responses of C7-T1 disc were also measured. The results of this study showed: The activation of cervical muscles decreased the NZ and ROM. The degree of decrease among different muscle dysfunctions, however, was not significantly different. The SPL dysfunction induced larger anterior shear force, while the SCM dysfunction exclusively induced extension moment. In conclusion, the muscle forces could stabilize the cervical spine, but significant decrease in spinal stability was not found among dysfunctions of different muscles. The SCM and SPL dysfunction may result in abnormal stress at the C7-T1 disc.

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Sagittal plane motion in the human lumbar spine: Comparison of the in vitro quasistatic neutral zone and dynamic motion parameters

Clinical Biomechanics ◽

10.1016/j.clinbiomech.2006.04.009 ◽

2006 ◽

Vol 21 (9) ◽

pp. 914-919 ◽

Cited By ~ 30

Author(s):

Ralph E. Gay ◽

Brice Ilharreborde ◽

Kristin Zhao ◽

Chunfeng Zhao ◽

Kai-Nan An

Keyword(s):

Lumbar Spine ◽

Sagittal Plane ◽

Plane Motion ◽

Neutral Zone ◽

Dynamic Motion ◽

Human Lumbar Spine ◽

Motion Parameters

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Study of the Distortion of the Indirect Angular Measurements of the Calcaneus Due to Perspective: In Vitro Testing

Sensors ◽

10.3390/s21082585 ◽

2021 ◽

Vol 21 (8) ◽

pp. 2585

Author(s):

Isidoro Espinosa-Moyano ◽

María Reina-Bueno ◽

Inmaculada C. Palomo-Toucedo ◽

José Rafael González-López ◽

José Manuel Castillo-López ◽

...

Keyword(s):

Sagittal Plane ◽

Frontal Plane ◽

In Vitro Study ◽

Body Segment ◽

The Real ◽

Foot Progression Angle ◽

Regression Formula ◽

Angular Measurements ◽

Kinematic Analyses

The study of the foot is relevant in kinematic analyses of gait. Images captured through a lens can be subjected to various aberrations or distortions that affect the measurements. An in vitro study was performed with a rearfoot simulator to compare the apparent degrees (photographed) with the real ones (placed in the simulator) in the plane of the rearfoot’s orientation, according to variations in the capture angle in other planes of space (the sagittal plane and transverse plane—the latter determined by the foot progression angle). The following regression formula was calculated to correct the distortion of the image: real frontal plane = 0.045 + (1.014 × apparent frontal plane) − (0.018 × sagittal plane × foot progression angle). Considering the results of this study, and already knowing its angle in the transverse and sagittal planes, it is possible to determine the angle of a simulated calcaneus with respect to the ground in the frontal plane, in spite of distortions caused by perspective and the lack of perpendicularity, by applying the above regression formula. The results show that the angular measurements of a body segment made on frames can produce erroneous data due to the variation in the perspective from which the image is taken. This distortion must be considered when determining the real values of the measurements.

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Robotic Simulation of the Effects of Surgical Placement of the ProDisc-L on Motion Segment Mechanics: An In Vitro Human Cadaveric Lumbar Model

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19398 ◽

2010 ◽

Author(s):

Braham K. Dhillon ◽

Daniel M. Wido ◽

Denis J. DiAngelo ◽

Rudolph Bertagnoli ◽

Brian P. Kelly

Keyword(s):

Sagittal Plane ◽

Total Disc Replacement ◽

Anatomical Location ◽

Rotational Axis ◽

Lumbar Total Disc Replacement ◽

Robotic Simulation ◽

Motion Segment ◽

Type Device ◽

Highly Sensitive

A variety of lumbar total disc replacement (TDR) designs exist for the treatment of disc pathologies and several of which have undergone clinical trials. A key design parameter for a constrained ball and socket type device is a fixed center of rotation (CoR). A previous study [1] demonstrated that the lumbar motion segment unit (MSU) was highly sensitive to the anatomical location of the sagittal plane rotational axis. Malalignment between the implant CoR and the inherent rotational axis of the MSU may lead to an overloaded or over-constrained condition.

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Long-term implant—bone fixation of the femoral component in total knee replacement

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/09544119jeim328 ◽

2008 ◽

Vol 222 (3) ◽

pp. 319-331 ◽

Cited By ~ 20

Author(s):

L Cristofolini ◽

S Affatato ◽

P Erani ◽

W Leardini ◽

D Tigani ◽

...

Keyword(s):

Total Knee Replacement ◽

Femoral Component ◽

Knee Replacement ◽

Sagittal Plane ◽

Clinical Test ◽

Migration Patterns ◽

Bone Fixation ◽

Total Knee

Success of total knee replacement (TKR) depends on the prosthetic design. Aseptic loosening of the femoral component is a significant failure mode that has received little attention. Despite the clinical relevance of failures, no protocol is available to test long-term implant—bone fixation of TKR in vitro. The scope of this work was to develop and validate a protocol to assess pre-clinically the fixation of TKR femoral components. An in vitro protocol was designed to apply a simplified but relevant loading profile using a 6-degrees-of-freedom knee simulator for 1 000 000 cycles. Implant—bone inducible micromotions and permanent migrations were measured at three locations throughout the test. After test completion, fatigue damage in the cement was quantified. The developed protocol was successfully applied to a commercial TKR. Additional tests were performed to exclude artefacts due to swelling or creep of the composite femur models. The components migrated distally; they tilted towards valgus in the frontal plane and in extension in the sagittal plane. The migration patterns were consistent with clinical roentgen-stereophotogrammetric recordings with TKR. Additional indicators were proposed that could quantify the tendency to loosen/stabilize. The type and amount of damage found in the cement, as well as the migration patterns, were consistent with clinical experience with the specific TKR investigated. The proposed pre-clinical test yielded repeatable results, which were consistent with the clinical literature. Therefore, its relevance and reliability was proved.

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Effect of Off-Axis Fluoroscopy Imaging on Two-Dimensional Kinematics in the Lumbar Spine: A Dynamic In Vitro Validation Study

Journal of Biomechanical Engineering ◽

10.1115/1.4032995 ◽

2016 ◽

Vol 138 (5) ◽

Cited By ~ 2

Author(s):

Kristin D. Zhao ◽

Ephraim I. Ben-Abraham ◽

Dixon J. Magnuson ◽

Jon J. Camp ◽

Lawrence J. Berglund ◽

...

Keyword(s):

Lumbar Spine ◽

Sagittal Plane ◽

Intervention Strategy ◽

Two Dimensional ◽

Regional Patterns ◽

Intervertebral Motion ◽

Measurement Variation ◽

Flexion Extension

Spine intersegmental motion parameters and the resultant regional patterns may be useful for biomechanical classification of low back pain (LBP) as well as assessing the appropriate intervention strategy. Because of its availability and reasonable cost, two-dimensional (2D) fluoroscopy has great potential as a diagnostic and evaluative tool. However, the technique of quantifying intervertebral motion in the lumbar spine must be validated, and the sensitivity assessed. The purpose of this investigation was to (1) compare synchronous fluoroscopic and optoelectronic measures of intervertebral rotations during dynamic flexion–extension movements in vitro and (2) assess the effect of C-arm rotation to simulate off-axis patient alignment on intervertebral kinematics measures. Six cadaveric lumbar–sacrum specimens were dissected, and active marker optoelectronic sensors were rigidly attached to the bodies of L2–S1. Fluoroscopic sequences and optoelectronic kinematic data (0.15-mm linear, 0.17–0.20 deg rotational, accuracy) were obtained simultaneously. After images were obtained in a true sagittal plane, the image receptor was rotated in 5 deg increments (posterior oblique angulations) from 5 deg to 15 deg. Quantitative motion analysis (qma) software was used to determine the intersegmental rotations from the fluoroscopic images. The mean absolute rotation differences between optoelectronic values and dynamic fluoroscopic values were less than 0.5 deg for all the motion segments at each off-axis fluoroscopic rotation and were not significantly different (P > 0.05) for any of the off-axis rotations of the fluoroscope. Small misalignments of the lumbar spine relative to the fluoroscope did not introduce measurement variation in relative segmental rotations greater than that observed when the spine and fluoroscope were perpendicular to each other, suggesting that fluoroscopic measures of relative segmental rotation during flexion–extension are likely robust, even when patient alignment is not perfect.

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Combined in Vivo/in Vitro Method to Study Anteriomedial Bundle Strain in the Anterior Cruciate Ligament Using a Dynamic Knee Simulator

Journal of Biomechanical Engineering ◽

10.1115/1.4023520 ◽

2013 ◽

Vol 135 (3) ◽

Cited By ~ 12

Author(s):

Karla Cassidy ◽

Gajendra Hangalur ◽

Preet Sabharwal ◽

Naveen Chandrashekar

Keyword(s):

Sagittal Plane ◽

Cruciate Ligament ◽

Muscle Group ◽

Muscle Forces ◽

Jump Landing ◽

Knee Simulator ◽

Anterior Cruciate ◽

Sports Activities

The mechanism of noncontact anterior cruciate ligament (ACL) injury is not well understood. It is partly because previous studies have been unable to relate dynamic knee muscle forces during sports activities such as landing from a jump to the strain in the ACL. We present a combined in vivo/in vitro method to relate the muscle group forces to ACL strain during jump-landing using a newly developed dynamic knee simulator. A dynamic knee simulator system was designed and developed to study the sagittal plane biomechanics of the knee. The simulator is computer controlled and uses six powerful electromechanical actuators to move a cadaver knee in the sagittal plane and to apply dynamic muscle forces at the insertion sites of the quadriceps, hamstring, and gastrocnemius muscle groups and the net moment at the hip joint. In order to demonstrate the capability of the simulator to simulate dynamic sports activities on cadaver knees, motion capture of a live subject landing from a jump on a force plate was performed. The kinematics and ground reaction force data obtained from the motion capture were input into a computer based musculoskeletal lower extremity model. From the model, the force-time profile of each muscle group across the knee during the movement was extracted, along with the motion profiles of the hip and ankle joints. This data was then programmed into the dynamic knee simulator system. Jump-landing was simulated on a cadaver knee successfully. Resulting strain in the ACL was measured using a differential variable reluctance transducer (DVRT). Our results show that the simulator has the capability to accurately simulate the dynamic sagittal plane motion and the dynamic muscle forces during jump-landing. The simulator has high repeatability. The ACL strain values agreed with the values reported in the literature. This combined in vivo/in vitro approach using this dynamic knee simulator system can be effectively used to study the relationship between sagittal plane muscle forces and ACL strain during dynamic activities.

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IN VITRO SIMULATION OF THE STANCE PHASE IN HUMAN GAIT

Journal of Musculoskeletal Research ◽

10.1142/s0218957701000490 ◽

2001 ◽

Vol 05 (02) ◽

pp. 113-121 ◽

Cited By ~ 24

Author(s):

Kyu-Jung Kim ◽

Harold B. Kitaoka ◽

Zong-Ping Luo ◽

Satoru Ozeki ◽

Lawrence J. Berglund ◽

...

Keyword(s):

Stance Phase ◽

Sagittal Plane ◽

Center Of Pressure ◽

Reaction Force ◽

Human Gait ◽

Heel Strike ◽

Foot And Ankle ◽

Vertical Ground Reaction Force ◽

Cross Sectional

The purpose of this study is to develop an electromechanical system for dynamic simulation of the stance phase of a human gait using cadaveric foot specimens. The system can be used for quantification of foot and ankle pathomechanics and design of foot and ankle reconstructive surgeries. Servo-pneumatic systems were used for application of the tibial weight loading and muscle loadings. A four-bar mechanism was constructed to provide the progressive motion of a tibia during the simulation while the external loadings were simultaneously applied. Muscle loadings were estimated based on the physiological cross-sectional area and normal electromyography (EMG) data with the assumption of the linear EMG–force relationship. Ad hoc tuning of the unknown muscle gains was conducted until a reasonable match with the normal vertical ground reaction force profile, center of pressure advancement, and characteristic foot motion events (heel strike, foot flat, heel rise and toe-off) could be made. Three cadaver feet and an artificial foot were tested with five repeated trials. The simulator reproduced the stance phase of a human gait in the sagittal plane with reasonable accuracy and consistency without compromising either kinematics or kinetics of the foot and ankle complex.

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Effects of occipital-atlas stabilization in the upper cervical spine kinematics: an in vitro study

Scientific Reports ◽

10.1038/s41598-021-90052-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

César Hidalgo-García ◽

Ana I. Lorente ◽

Carlos López-de-Celis ◽

Orosia Lucha-López ◽

Miguel Malo-Urriés ◽

...

Keyword(s):

Cervical Spine ◽

Sagittal Plane ◽

Frontal Plane ◽

In Vitro Study ◽

Upper Cervical Spine ◽

Lateral Flexion ◽

Alar Ligament ◽

Before And After ◽

Upper Cervical

AbstractThis study compares upper cervical spine range of motion (ROM) in the three cardinal planes before and after occiput-atlas (C0–C1) stabilization. After the dissection of the superficial structures to the alar ligament and the fixation of C2, ten cryopreserved upper cervical columns were manually mobilized in the three cardinal planes of movement without and with a screw stabilization of C0–C1. Upper cervical ROM and mobilization force were measured using the Vicon motion capture system and a load cell respectively. The ROM without C0–C1 stabilization was 19.8° ± 5.2° in flexion and 14.3° ± 7.7° in extension. With stabilization, the ROM was 11.5° ± 4.3° and 6.6° ± 3.5°, respectively. The ROM without C0–C1 stabilization was 4.7° ± 2.3° in right lateral flexion and 5.6° ± 3.2° in left lateral flexion. With stabilization, the ROM was 2.3° ± 1.4° and 2.3° ± 1.2°, respectively. The ROM without C0–C1 stabilization was 33.9° ± 6.7° in right rotation and 28.0° ± 6.9° in left rotation. With stabilization, the ROM was 28.5° ± 7.0° and 23.7° ± 8.5° respectively. Stabilization of C0–C1 reduced the upper cervical ROM by 46.9% in the sagittal plane, 55.3% in the frontal plane, and 15.6% in the transverse plane. Also, the resistance to movement during upper cervical mobilization increased following C0–C1 stabilization.

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Ultrastructural Investigations of the Contractile Filaments of Amoebae

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050950 ◽

1974 ◽

Vol 32 ◽

pp. 188-189

Author(s):

P.L. Moore

Keyword(s):

Cytoplasmic Streaming ◽

Three Dimensional ◽

Freeze Fracture ◽

Amoeboid Movement ◽

Different Types ◽

Chemical Conditions ◽

Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

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