Abstract:Objective Recently, interspinous process devices have attracted much attention since they can be implanted between the lumbar spinous processes (LSP) of patients with degenerative disc disease (DDD) and degenerative spondylolisthesis (DLS) using a minimally invasive manner. However, the motion characters of the LSP in the DLS and DDD patients have not been reported. This study is aimed at investigating the kinematics of the lumbar spinous processes in patients with DLS and DDD. Methods Ten patients with DDD at… Show more
“…The range of inter-vertebral axes or vertebral displacements, measured from no movement (minimum displacement between two successive frames at the neutral or at the end-of-range position) to maximum, was as follows: inter-vertebral axis translation (2.35 cm/L2–L3), inter-vertebral axis rotation (17.29°/L2–L3), vertebral translation (1.34 cm/L2), and vertebral rotation (15.86°/L2) displacements; inter-vertebral axis translation (1.95 cm/L3–L4), inter-vertebral axis rotation (11.42°/L3–L4), vertebral translation (1.23 cm/L3), and vertebral rotation (13.09°/L3); and vertebral translation (0.94 cm/L4) and vertebral rotation (8.49°/L3); the maximum range of movements was observed at the upper axis (L2–L3) and the cranial L2 vertebra for all translation and rotations. The range of excursions, quantified at the upper intervertebral axis and the L2 vertebra, were similar to overall range of motion reported in earlier studies studying physiologic range of the lumbar spine motion [14,20,21].…”
Study Design
Between-session reliability of a magnetic resonance imaging (MRI) based experimental technique to quantify lumbar inter-vertebral motion in humans.
Purpose
We have developed a novel, dynamic, MRI-based approach for quantifying
in vivo
lumbar inter-vertebral motion. In this study, we present the protocol’s reliability results to quantify inter-vertebral spine motion.
Overview of Literature
Morphometric studies on intervertebral displacements using static, supine MRI and quantification of dynamic spine motion using different X-ray based radiography techniques are commonly found in the literature. However, reliability testing of techniques assessing real-time lumbar intervertebral motion using weight-bearing MRI has rarely been reported.
Methods
Ten adults without a history of back pain performed a side-bending task on two separate occasions, inside an open-MRI, in a weight-bearing, upright position. The images were acquired during the task using a dynamic magnetic resonance (MR) sequence. The MRI imaging space was externally calibrated before the study to recreate the imaging volume for subsequent use in an animation software. The dynamic MR images were processed to create side-bending movement animations in the virtual environment. Participant-specific three-dimensional models were manually superimposed over vertebral image silhouettes in a sequence of image frames, representing the motion trials. Inter-vertebral axes and translation and rotational displacements of vertebrae were quantified using the animation software.
Results
Quantification of inter-vertebral rotations and translations shows high reliability. Between-session reliability results yielded high values for the intra-class correlation coefficient (0.86–0.93), coefficient of variation (13.3%–16.04%), and Pearson’s correlation coefficients (0.89–0.98).
Conclusions
This technique may be developed further to improve its speed and accuracy for diagnostic applications, to study
in vivo
spine stability, and to assess outcomes of surgical and non-surgical interventions applied to manage pathological spine motion.
“…The range of inter-vertebral axes or vertebral displacements, measured from no movement (minimum displacement between two successive frames at the neutral or at the end-of-range position) to maximum, was as follows: inter-vertebral axis translation (2.35 cm/L2–L3), inter-vertebral axis rotation (17.29°/L2–L3), vertebral translation (1.34 cm/L2), and vertebral rotation (15.86°/L2) displacements; inter-vertebral axis translation (1.95 cm/L3–L4), inter-vertebral axis rotation (11.42°/L3–L4), vertebral translation (1.23 cm/L3), and vertebral rotation (13.09°/L3); and vertebral translation (0.94 cm/L4) and vertebral rotation (8.49°/L3); the maximum range of movements was observed at the upper axis (L2–L3) and the cranial L2 vertebra for all translation and rotations. The range of excursions, quantified at the upper intervertebral axis and the L2 vertebra, were similar to overall range of motion reported in earlier studies studying physiologic range of the lumbar spine motion [14,20,21].…”
Study Design
Between-session reliability of a magnetic resonance imaging (MRI) based experimental technique to quantify lumbar inter-vertebral motion in humans.
Purpose
We have developed a novel, dynamic, MRI-based approach for quantifying
in vivo
lumbar inter-vertebral motion. In this study, we present the protocol’s reliability results to quantify inter-vertebral spine motion.
Overview of Literature
Morphometric studies on intervertebral displacements using static, supine MRI and quantification of dynamic spine motion using different X-ray based radiography techniques are commonly found in the literature. However, reliability testing of techniques assessing real-time lumbar intervertebral motion using weight-bearing MRI has rarely been reported.
Methods
Ten adults without a history of back pain performed a side-bending task on two separate occasions, inside an open-MRI, in a weight-bearing, upright position. The images were acquired during the task using a dynamic magnetic resonance (MR) sequence. The MRI imaging space was externally calibrated before the study to recreate the imaging volume for subsequent use in an animation software. The dynamic MR images were processed to create side-bending movement animations in the virtual environment. Participant-specific three-dimensional models were manually superimposed over vertebral image silhouettes in a sequence of image frames, representing the motion trials. Inter-vertebral axes and translation and rotational displacements of vertebrae were quantified using the animation software.
Results
Quantification of inter-vertebral rotations and translations shows high reliability. Between-session reliability results yielded high values for the intra-class correlation coefficient (0.86–0.93), coefficient of variation (13.3%–16.04%), and Pearson’s correlation coefficients (0.89–0.98).
Conclusions
This technique may be developed further to improve its speed and accuracy for diagnostic applications, to study
in vivo
spine stability, and to assess outcomes of surgical and non-surgical interventions applied to manage pathological spine motion.
“…Besides, significant differences were found in left/right rotation at all three levels. Yao et al reported that, in non-weight-bearing supine, standing, and extension positions, ISP were physically smaller in patients with DDD than healthy subjects [11]. In the current study, similar trends were exhibited in all groups.…”
Section: Discussionsupporting
confidence: 81%
“…Therefore, we could determine the positions of specific vertebrae and spinous processes for each pose. In a similar study by Yao et al [11], the accuracy of this technique was within 0.6 mm for translation and 1.3° for rotation.Fig. 1
a MR image of human lumbar spine of DDD patients.…”
Section: Methodsmentioning
confidence: 52%
“…Yao et al reported that, in supine, standing, and extension positions, ISP were physically smaller in patients with DDD than healthy subjects. [11]. The repeatability is 0.3 mm for translation and 0.6° for rotation.…”
BackgroundData about minimally invasive surgery for the treatment of patients with degenerative disc disease (DDD) has been reported. However, no quantitative knowledge about the biomechanical characteristics of the spinous processes in patients with DDD after operation was reported in the literature.MethodsFourteen adult patients with DDD at the L3-4 level were recruited and scanned using computed tomography (CT) to construct three-dimensional (3D) anatomical vertebral models of L2-5. These patients were asked to maintain four positions to acquire 6DOF data about the area of the spine being investigated (L2-5). Fluoroscopy was used to capture spinal motion. 6DOF data from the fluoroscopic images of the four positions was compared to evaluate the kinematics before operation and 6 months after direct lateral interbody fixation (DLIF).ResultsAltered kinematics were found mainly in rotation. For the images captured while patients were in the supine position, no significant differences were detected in different functional positions before and after operation. At other positions, the most kinematic involved level was the L3-4 level, which was followed by the L4-5 level. The range of flexion-extension motion at all levels decreased after operation (by an average of 1° to 7°) while different trends were found in left-right bending/rotation. Overall, after surgical treatment, functional activities were partially restored.ConclusionsOverall the lumbar spinous processes (LSP) at each level responded differently, regarding rotation, before and after DLIF. This data provides new insights for the evaluation of function before and after surgical treatment in patients with LSP disease.
“…Instability in the clinical context designates a condition that not only is thought to be denoted by excessive vertebral movements in response to applied loads, and suggests that these excessive displacements result in pain, progressive deformity and risk of neurologic damage. 8,43,44 Inspection, palpatory assessment and passive testing of vertebral mobility and pain with prone instability testing in the clinic, palpation of step-off and straight leg raise tests form the mainstay of clinical diagnosis of spine instability. The quintessential radiological assessment of instability being the calculation of static, end-range inter-vertebral displacement from radiographs in maximum flexion and extension (first reported in 1944), it is hardy a guess that interpretations of spine stability from static end-points on dynamic stability of spine segments across their ROM, may be misleading.…”
Section: The Next Level Of Complexity: Anatomical Instabilitymentioning
Background Changes in the load-displacement relationship in spine segments suggesting alterations in biomechanical stiffness may not yield significant clinical information. Changes in Spine stiffness may arise secondary to neuro-muscular adjustments in the para-spinal muscles and may not be associated with physical anatomical laxity or motion restrictions at segmental articulations. Segmental stiffness may vary dynamically at different zones within the range-of-motion, suggesting a non-linear load-displacement relationship during motion. There is no linear, mechanistic relationship between spine pain and biomechanical markers of spine instability.
Objective To review diagnostic assessment approaches of spine instability based on palpatory techniques, end-of-range radiography and imaging in light of our current understanding of biomechanical spine stability.
Method The Medline and PubMed databases were screened for primary medical and engineering research articles and reviews on spine stability. Information related to bio-mechanical concepts and clinical decision-making were extracted and synthesized. Spine stability was described in two classical forms, the structural (anatomical) and the functional (physiological), the implications of static and dynamic instability was described in terms of biomechanical and mathematical models used to understand etiology of non-specific back pain.
Results Evidence supports the view that dynamic adaptations in the load-displacement relationship of the spine may be resistive or assistive, depending on task-specific movements. Diagnosis of instability is based on structural and functional integrity of the segments in a static or dynamic context.
Conclusion Development of specific criteria to define clinical spine stability, compatible with system-based biomechanical concept of spine stiffness, is an ongoing topic in clinical and basic science research.
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