Abstract:In vitro biomechanical studies of the osteoligamentous spine are widely used to characterize normal biomechanics, identify injury mechanisms, and assess the effects of degeneration and surgical instrumentation on spine mechanics. The objective of this study was to determine how well four standards in vitro loading paradigms replicate in vivo kinematics with regards to the instantaneous center of rotation and arthrokinematics in relation to disc deformation. In vivo data were previously collected from 20 asympt… Show more
“… 46 On top of this, the increased contribution of the C6–C7 segment to LB in this position may indicate the anterior and superior shift of the center of rotation observed at this level. 1 , 81 (see Fig. 1 b).…”
Section: Healthy Conditionsmentioning
confidence: 92%
“… 15 , 58 , 71 The latest studies on the matter focus on the instant center of rotation (ICR), which is defined as “the point at which the three-dimensional axis of rotation vector intersected the sagittal anatomical plane of the inferior vertebra”. 2 , 81 Some studies narrow this investigation down to the anteroposterior (AP) direction, 88 while others provide a circular estimate of possible distribution areas of ICR in the sagittal plane at each level in the course of in vivo movements. 42 Figure 5 Center of rotation as observed in studies involving healthy participants and providing data eligible for inclusion in a figure.…”
Section: Healthy Conditionsmentioning
confidence: 99%
“…Studies published before 2012 1 , 15 , 22 , 71 were based on radiographs taken between the initial and final position of the studied movements, while studies published later employed a combination of computed tomography (CT) or magnetic resonance imaging (MRI) with biplanar radiography or (video)fluoroscopy. 2 , 42 , 58 , 81 , 88 The former predominantly report a stationary ICR location at each cervical segment, which derives from the average of measurements collected from static full-flexion and extension radiographs and from radiographs collected during slow sagittal movement. 14 The techniques used by the latter group of studies provide a more accurate account about motion of the ICR during the dynamic flexion–extension cycle and identify bone location and three-dimensional orientation with sub-millimeter accuracy.…”
Knowledge of spinal kinematics is essential for the diagnosis and management of spinal diseases. Distinguishing between physiological and pathological motion patterns can help diagnose these diseases, plan surgical interventions and improve relevant tools and software. During the last decades, numerous studies based on diverse methodologies attempted to elucidate spinal mobility in different planes of motion. The authors aimed to summarize and compare the evidence about cervical spine kinematics under healthy and degenerative conditions. This includes an illustrated description of the spectrum of physiological cervical spine kinematics, followed by a comparable presentation of kinematics of the degenerative cervical spine. Data was obtained through a systematic MEDLINE search including studies on angular/translational segmental motion contribution, range of motion, coupling and center of rotation. As far as the degenerative conditions are concerned, kinematic data regarding disc degeneration and spondylolisthesis were available. Although the majority of the studies identified repeating motion patterns for most motion planes, discrepancies associated with limited sample sizes and different imaging techniques and/or spine configurations, were noted. Among healthy/asymptomatic individuals, flexion extension (FE) and lateral bending (LB) are mainly facilitated by the subaxial cervical spine. C4–C5 and C5–C6 were the major FE contributors in the reported studies, exceeding the motion contribution of sub-adjacent segments. Axial rotation (AR) greatly depends on C1–C2. FE range of motion (ROM) is distributed between the atlantoaxial and subaxial segments, while AR ROM stems mainly from the former and LB ROM from the latter. In coupled motion rotation is quantitatively predominant over translation. Motion migrates caudally from C1–C2 and the center of rotation (COR) translocates anteriorly and superiorly for each successive subaxial segment. In degenerative settings, concurrent or subsequent lesions render the association between diseases and mobility alterations challenging. The affected segments seem to maintain translational and angular motion in early and moderate degeneration. However, the progression of degeneration restrains mobility, which seems to be maintained or compensated by adjacent non-affected segments. While the kinematics of the healthy cervical spine have been addressed by multiple studies, the entire nosological and kinematic spectrum of cervical spine degeneration is partially addressed. Large—scale in vivo studies can complement the existing evidence, cover the gaps and pave the way to technological and clinical breakthroughs.
“… 46 On top of this, the increased contribution of the C6–C7 segment to LB in this position may indicate the anterior and superior shift of the center of rotation observed at this level. 1 , 81 (see Fig. 1 b).…”
Section: Healthy Conditionsmentioning
confidence: 92%
“… 15 , 58 , 71 The latest studies on the matter focus on the instant center of rotation (ICR), which is defined as “the point at which the three-dimensional axis of rotation vector intersected the sagittal anatomical plane of the inferior vertebra”. 2 , 81 Some studies narrow this investigation down to the anteroposterior (AP) direction, 88 while others provide a circular estimate of possible distribution areas of ICR in the sagittal plane at each level in the course of in vivo movements. 42 Figure 5 Center of rotation as observed in studies involving healthy participants and providing data eligible for inclusion in a figure.…”
Section: Healthy Conditionsmentioning
confidence: 99%
“…Studies published before 2012 1 , 15 , 22 , 71 were based on radiographs taken between the initial and final position of the studied movements, while studies published later employed a combination of computed tomography (CT) or magnetic resonance imaging (MRI) with biplanar radiography or (video)fluoroscopy. 2 , 42 , 58 , 81 , 88 The former predominantly report a stationary ICR location at each cervical segment, which derives from the average of measurements collected from static full-flexion and extension radiographs and from radiographs collected during slow sagittal movement. 14 The techniques used by the latter group of studies provide a more accurate account about motion of the ICR during the dynamic flexion–extension cycle and identify bone location and three-dimensional orientation with sub-millimeter accuracy.…”
Knowledge of spinal kinematics is essential for the diagnosis and management of spinal diseases. Distinguishing between physiological and pathological motion patterns can help diagnose these diseases, plan surgical interventions and improve relevant tools and software. During the last decades, numerous studies based on diverse methodologies attempted to elucidate spinal mobility in different planes of motion. The authors aimed to summarize and compare the evidence about cervical spine kinematics under healthy and degenerative conditions. This includes an illustrated description of the spectrum of physiological cervical spine kinematics, followed by a comparable presentation of kinematics of the degenerative cervical spine. Data was obtained through a systematic MEDLINE search including studies on angular/translational segmental motion contribution, range of motion, coupling and center of rotation. As far as the degenerative conditions are concerned, kinematic data regarding disc degeneration and spondylolisthesis were available. Although the majority of the studies identified repeating motion patterns for most motion planes, discrepancies associated with limited sample sizes and different imaging techniques and/or spine configurations, were noted. Among healthy/asymptomatic individuals, flexion extension (FE) and lateral bending (LB) are mainly facilitated by the subaxial cervical spine. C4–C5 and C5–C6 were the major FE contributors in the reported studies, exceeding the motion contribution of sub-adjacent segments. Axial rotation (AR) greatly depends on C1–C2. FE range of motion (ROM) is distributed between the atlantoaxial and subaxial segments, while AR ROM stems mainly from the former and LB ROM from the latter. In coupled motion rotation is quantitatively predominant over translation. Motion migrates caudally from C1–C2 and the center of rotation (COR) translocates anteriorly and superiorly for each successive subaxial segment. In degenerative settings, concurrent or subsequent lesions render the association between diseases and mobility alterations challenging. The affected segments seem to maintain translational and angular motion in early and moderate degeneration. However, the progression of degeneration restrains mobility, which seems to be maintained or compensated by adjacent non-affected segments. While the kinematics of the healthy cervical spine have been addressed by multiple studies, the entire nosological and kinematic spectrum of cervical spine degeneration is partially addressed. Large—scale in vivo studies can complement the existing evidence, cover the gaps and pave the way to technological and clinical breakthroughs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
