Inertial Loading of the Human Cervical Spine

1997 ◽  
Vol 119 (3) ◽  
pp. 237-240 ◽  
Author(s):  
N. Yoganandan ◽  
F. A. Pintar
Keyword(s):  
Cervical Spine ◽  
Wave Form ◽  
Spine Biomechanics ◽  
Human Cadaver ◽  
Kinematic Data ◽  
Flexion Extension ◽  
Angular Velocities ◽  
Applied Forces ◽  
Inertial Loading ◽  
Flexion And Extension

While the majority of experimental cervical spine biomechanics research has been conducted using slowly applied forces and/or moments, or dynamically applied forces with contact, little research has been performed to delineate the biomechanics of the human neck under inertial “noncontact” type forces. This study was designed to develop a comprehensive methodology to induce these loads. A minisled pendulum experimental setup was designed to test specimens (such as human cadaver neck) at subfailure or failure levels under different loading modalities including flexion, extension, and lateral bending. The system allows acceleration/deceleration input with varying wave form shapes. The test setup dynamically records the input and output strength information such as forces, accelerations, moments, and angular velocities; it also has the flexibility to obtain the temporal overall and local kinematic data of the cervical spine components at every vertebral level. These data will permit a complete biomechanical structural analysis. In this paper, the feasibility of the methodology is demonstrated by subjecting a human cadaver head-neck complex with intact musculature and skin under inertial flexion and extension whiplash loading at two velocities.

Comparison of cervical spine kinematics using a fluoroscopic model for adjacent segment degeneration

2007 ◽  
Vol 7 (5) ◽  
pp. 509-513 ◽  
Author(s):  
Joseph S. Cheng ◽  
Fei Liu ◽  
Richard D. Komistek ◽  
Mohamed R. Mahfouz ◽  
Adrija Sharma ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Adjacent Segment Degeneration ◽  
Adjacent Segment ◽  
Healthy Individuals ◽  
Inverse Dynamic ◽  
Kinematic Data ◽  
Spine Kinematics ◽  
Flexion Extension ◽  
Cervical Motion ◽  
Flexion And Extension

Object In this cervical spine kinematics study the authors evaluate the motions and forces in the normal, degenerative, and fused states to assess how alteration in the cervical motion segment affects adjacent segment degeneration and spondylosis. Methods Fluoroscopic images obtained in 30 individuals (10 in each group with disease at C5–6) undergoing flexion/extension motions were collected. Kinematic data were obtained from the fluoroscopic images and analyzed with an inverse dynamic mathematical model of the cervical spine that was developed for this analysis. Results During 20° flexion to 15° extension, average relative angles at the adjacent levels of C6–7 and C4–5 in the fused patients were 13.4° and 8.8° versus 3.7° and 4.8° in the healthy individuals. Differences at C3–4 averaged only about 1°. Maximum transverse forces in the fused spines were two times the skull weight at C6–7 and one times the skull weight at C4–5, compared with 0.2 times the skull weight and 0.3 times the skull weight in the healthy individuals. Vertical forces ranged from 1.6 to 2.6 times the skull weight at C6–7 and from 1.2 to 2.5 times the skull weight at C4–5 in the patients who had undergone fusion, and from 1.4 to 3.1 times the skull weight and from 0.9 to 3.3 times the skull weight, respectively, in the volunteers. Conclusions Adjacent-segment degeneration may occur in patients with fusion due to increased motions and forces at both adjacent levels when compared with healthy individuals in a comparable flexion and extension range.

Cervical Spine Movement Sequencing During Flexion-Extension

2011 ◽  
Author(s):  
William J. Anderst ◽  
Michelle Schafman ◽  
William F. Donaldson ◽  
Joon Y. Lee ◽  
James D. Kang
Keyword(s):  
Cervical Spine ◽  
Range Of Motion ◽  
Daily Living ◽  
X Rays ◽  
Clinical Tool ◽  
Normal Range ◽  
Kinematic Data ◽  
Flexion Extension ◽  
Functional Movements ◽  
Spine Movement

Static flexion-extension x-rays are the most common clinical tool used to assess abnormal motion of the cervical spine. Despite their widespread use (over 168,000 cases per year), the clinical efficacy of flexion-extension radiographs of the cervical spine has yet to be proven1. Limitations of static flexion-extension x-rays include data collection during static positions that may not accurately represent dynamic behavior, and the fact that data is collected at end range of motion positions, not in more frequently encountered mid-range positions. Consequently, static x-rays may not reveal movement abnormalities that occur during activities of daily living and lead to pain and degeneration. Therefore, it may be advantageous to analyze cervical spine kinematic data collected during dynamic, functional movements performed through an entire range of motion (not just the endpoints). Furthermore, the literature confirms there is substantial variability in “normal” range of motion and translation during flexion-extension1, making it difficult to reliably identify abnormal motion. Therefore, it may also be beneficial to evaluate alternative motion parameters that may reliably identify abnormal motion.

Kinematics of the Cervical Spine: Path of the Instant Axis of Rotation in Flexion and Extension

2000 ◽  
Author(s):  
Denis J. DiAngelo ◽  
Keith Vossel ◽  
Kevin T. Foley
Keyword(s):  
Cervical Spine ◽  
Vertebral Body ◽  
Measurement System ◽  
Axis Of Rotation ◽  
Rotational Components ◽  
Flexion Extension ◽  
Vertebral Kinematics ◽  
Set Up ◽  
Flexion And Extension

Abstract Previous Biomechanical Measures of Vertebral Kinematics. White and Panjabi (1990) have suggested that the Instant Axis of Rotation (IAR) be used to describe the 2-D motion of a vertebral body. However, the location of the IAR for the cervical spine varies amongst spine researchers. White and Panjabi (1990) have suggested the IAR of each vertebra is located in the anterior region of the subjacent vertebra; Porterfield and Derosa (1995) suggest it is located in the mid-region of the subjacent vertebra; and Mameren et al. (1992) found it to lay in the central region of the vertebral body being tracked. Goel and Winterbottom (1991) stated that during flexion and extension, the axis of rotation is located somewhere within the vertebral body itself. Unfortunately, no accurate calculations of the IAR paths of the cervical spine exist; typical vertebral measurements only include the rotational components. Estimation of the vertebrae’s IAR location in vitro depends on the experimental set-up (motion and loading mechanics), anatomical structure, mathematical reduction technique, and accuracy of the measurement equipment. Crisco et al. (1994) determined the theoretical error in calculating the location of the IAR as a function of the measurement system specifications and the placement of the markers on the spinal body. Conventional tracking systems having translational resolutions of 0.1mm to 0.05mm were found to calculate the location of the IAR to within 7mm to 10mm, respectively. This error became significantly larger as the resolution of the measurement system dropped off. Most investigators only calculate the rotational components of a body’s motion and seldom calculate the error involved in their mathematical analysis. Furthermore, overall head movement is often reported (i.e., C0 to T1), but smaller flexion-extension movements of individual spinal bodies are either void in the literature or suspect to large theoretical errors. The objective of the study was to determine the IAR of the sub-axial cervical vertebral bodies under physiological flexion and extension conditions in vitro.

Influence of Laminotomies and Laminectomies on Cervical Spine Biomechanics under Combined Flexion-Extension

2004 ◽  
Vol 20 (3) ◽  
pp. 243-259 ◽  
Author(s):  
Hong-Wan Ng ◽  
Ee-Chon Teo ◽  
QingHang Zhang
Keyword(s):  
Cervical Spine ◽  
Surgical Techniques ◽  
Internal Stresses ◽  
Published Data ◽  
Spine Biomechanics ◽  
Element Analysis ◽  
Flexion Extension ◽  
Biomechanical Responses ◽  
Biomechanical Changes

Posterior decompressive techniques including one- and two-level laminotomies and laminectomies are often used in treating cervical stenosis. Previously, several in vitro studies were conducted to help us understand the biomechanical changes occurring in the cervical spine after these surgical techniques. However, changes in the intersegmental flexibility under combined flexion-extension remain unclear. In this study, a 3-D nonlinear intact model of the C2–C7 was developed to evaluate the influence of one- and two-level laminotomies and laminectomies on the intersegmental moment rotational responses and internal stresses. The intact model was validated by comparing the predicted responses against experimental data. The validated model was then modified to simulate various surgical techniques for finite element analysis. Results showed that one- and two-level laminectomies increase the C2–C7 rotation motions by about 15% and 20%, respectively. The predicted increase in rotational motions also correlated well with the published data. Furthermore, results indicated that laminectomies would influence the biomechanical responses on both the affected and adjacent motion segments. In contrast, laminotomies have no significant effects on cervical biomechanics. To conduct a one-level laminectomy study, current findings indicate that it takes at least five motion segments to capture the immediate postsurgical biomechanical changes accurately and realistically. Minimally invasive cervical spine surgeries with one- or two-level laminotomies are preferred over one- and two-level laminectomies. Also, there is no consideration as to the efficacy of the two techniques in decompressing the spinal cord or nerve roots, which is the goal of the surgery, but is not examined in this study.

scholarly journals Maximum Velocities in Flexion and Extension Actions for Sport

2016 ◽  
Vol 50 (1) ◽  
pp. 37-44 ◽  
Author(s):  
David M. Jessop ◽  
Matthew T.G. Pain
Keyword(s):  
High Speed ◽  
Lower Limbs ◽  
Movement Speed ◽  
Anova Analysis ◽  
Maximum Flexion ◽  
Movement Strategies ◽  
Flexion Extension ◽  
Angular Velocities ◽  
Muscle Models ◽  
Flexion And Extension

AbstractSpeed of movement is fundamental to the outcome of many human actions. A variety of techniques can be implemented in order to maximise movement speed depending on the goal of the movement, constraints, and the time available. Knowing maximum movement velocities is therefore useful for developing movement strategies but also as input into muscle models. The aim of this study was to determine maximum flexion and extension velocities about the major joints in upper and lower limbs. Seven university to international level male competitors performed flexion/extension at each of the major joints in the upper and lower limbs under three conditions: isolated; isolated with a countermovement; involvement of proximal segments. 500 Hz planar high speed video was used to calculate velocities. The highest angular velocities in the upper and lower limb were 50.0 rad·s-1 and 28.4 rad·s-1, at the wrist and knee, respectively. As was true for most joints, these were achieved with the involvement of proximal segments, however, ANOVA analysis showed few significant differences (p<0.05) between conditions. Different segment masses, structures and locations produced differing results, in the upper and lower limbs, highlighting the requirement of segment specific strategies for maximal movements.

scholarly journals Transferability between Isolated Joint Torques and a Maximum Polyarticular Task: A Preliminary Study

2016 ◽  
Vol 50 (1) ◽  
pp. 5-14
Author(s):  
Antony Costes ◽  
David Villeger ◽  
Pierre Moretto ◽  
Bruno Watier
Keyword(s):  
Angular Velocity ◽  
Significant Relationship ◽  
Inverse Dynamics ◽  
Knee Extension ◽  
Maximum Power ◽  
Joint Torque ◽  
Joint Torques ◽  
Flexion Extension ◽  
Angular Velocities ◽  
Flexion And Extension

AbstractThe aims of this study were to determine if isolated maximum joint torques and joint torques during a maximum polyarticular task (i.e. cycling at maximum power) are correlated despite joint angle and velocity discrepancies, and to assess if an isolated joint-specific torque production capability at slow angular velocity is related to cycling power. Nine cyclists completed two different evaluations of their lower limb maximum joint torques. Maximum Isolated Torques were assessed on isolated joint movements using an isokinetic ergometer and Maximum Pedalling Torques were calculated at the ankle, knee and hip for flexion and extension by inverse dynamics during cycling at maximum power. A correlation analysis was made between Maximum Isolated Torques and respective Maximum Pedalling Torques [3 joints x (flexion + extension)], showing no significant relationship. Only one significant relationship was found between cycling maximum power and knee extension Maximum Isolated Torque (r=0.68, p<0.05). Lack of correlations between isolated joint torques measured at slow angular velocity and the same joint torques involved in a polyarticular task shows that transfers between both are not direct due to differences in joint angular velocities and in mono-articular versus poly articular joint torque production capabilities. However, this study confirms that maximum power in cycling is correlated with slow angular velocity mono-articular maximum knee extension torque.

The role of flexion and extension computed tomography with reconstruction in clearing the cervical spine in trauma patients: a pilot study

2011 ◽  
Vol 14 (3) ◽  
pp. 341-347 ◽  
Author(s):  
Rishi Wadhwa ◽  
Samer Shamieh ◽  
Justin Haydel ◽  
Gloria Caldito ◽  
Mallory Williams ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Prospective Study ◽  
Efficient Method ◽  
Spinal Cord Injuries ◽  
Spinal Column ◽  
Case Series ◽  
Ct Scanning ◽  
Cervical Region ◽  
Flexion Extension ◽  
Flexion And Extension

Object As a result of spinal trauma, approximately 12,000 individuals become quadriplegic or paraplegic each year in the US. The cervical spine is the most frequently injured part of the spinal column, and approximately 60% of spinal cord injuries involve the cervical region. The cervical collar remains the best method of prehospital spinal stabilization. Following trauma, difficulty securing an airway, the shielding of life-threatening injuries, and pressure ulcers are just a few of the serious problems that may be encountered in patients placed in cervical collars. The authors' goal was to develop an efficient method of clearing the cervical spine, by incorporating flexion and extension CT scanning with reconstruction (FECTR) into a trauma protocol. Methods This prospective study reviewed consecutive patients evaluated by the neurosurgery and trauma services who underwent FECTR. Imaging studies were reviewed using the Picture Activating and Communication System. The incidence of injury detection was recorded, and detection of otherwise-missed cervical spinal injuries using FECTR and CT scanning were also recorded. This technique was also applied, without causing any new neurological complications, for comatose patients if the original CT showed no suspicion of unstable injury. The study end point was determination of the presence of cervical spinal column injury that would pose a threat of instability or injury to the patient. Results Seventy-seven consecutive patients who underwent FECTR were identified. Far superior visualization of the cervicothoracic junction was achieved compared with flexion-extension cervical spine radiographs. In this case series, the sensitivity and specificity, respectively, of both FECTR and CT were 80% and 98.6% for all radiographic abnormalities. More importantly, for clinically unstable injuries, FECTR had a sensitivity of 100%. The use of FECTR added approximately 10–12 minutes to the time required for CT scanning. Conclusions The authors' initial findings show FECTR to be a safe, effective, and efficient method of posttraumatic cervical spine clearance. In unconscious or obtunded patients, FECTR facilitates cervical spine clearance with a high degree of accuracy. A larger prospective study is needed to confirm these findings.

Motion Analysis of the Cervical Spine

2004 ◽  
Vol 9 (5) ◽  
pp. 1-11
Author(s):  
Patrick R. Luers
Keyword(s):  
Cervical Spine ◽  
Intervertebral Disk ◽  
Radiographic Evaluation ◽  
Ligamentous Injury ◽  
Pattern Of Injury ◽  
Motion Segment ◽  
Single Pattern ◽  
Compensatory Motion ◽  
Loss Of Motion ◽  
Flexion And Extension

Abstract The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, defines a motion segment as “two adjacent vertebrae, the intervertebral disk, the apophyseal or facet joints, and ligamentous structures between the vertebrae.” The range of motion from segment to segment varies, and loss of motion segment integrity is defined as “an anteroposterior motion of one vertebra over another that is greater than 3.5 mm in the cervical spine, greater than 2.5 mm in the thoracic spine, and greater than 4.5 mm in the lumbar spine.” Multiple etiologies are associated with increased motion in the cervical spine; some are physiologic or compensatory and others are pathologic. The standard radiographic evaluation of instability and ligamentous injury in the cervical spine consists of lateral flexion and extension x-ray views, but no single pattern of injury is identified in whiplash injuries. Fluoroscopy or cineradiographic techniques may be more sensitive than other methods for evaluating subtle abnormal motion in the cervical spine. The increased motion thus detected then must be evaluated to determine whether it represents normal physiologic motion, normal compensatory motion, motion related to underlying degenerative disk and/or facet disease, or increased motion related to ligamentous injury. Imaging studies should be performed and interpreted as instructed in the AMA Guides.

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