OBJECTIVE: To evaluate a prototype sagittal plane surrogate neck model designed to provide a biofidelic response to head-first impacts with a straightened cervical posture. METHODS: Published biomechanical studies were used in the design to define the range of motion (ROM) and stiffness in both flexion-extension rotation and axial compression. The ...

Lumbar spinal stenosis is a common problem that is receiving attention with the advent of novel treatment procedures. Prior positional MRI studies demonstrated lumbar canal diameter changes with flexion and extension. There have not been any studies to examine the amount of spinal canal diameter change relative to the amount ...

STUDY DESIGN: A blind, repeated-measure design was employed in the study. OBJECTIVE: To quantitatively measure the percentage contribution of segmental angular motion during different motion ranges of cervical flexion-extension for clinical applications and better understanding of cervical biomechanics. SUMMARY OF BACKGROUND DATA: Restriction of cervical motion is a major symptom ...

STUDY DESIGN: Prospective case series OBJECTIVE: This was designed to precisely measure motion after posterior dynamic stabilization using Dynesys instrumentation. SUMMARY OF BACKGROUND DATA: The Dynesys posterior dynamic stabilization system, which stabilizes the spinal segment while potentially decreasing the risk of adjacent segment disease, is undergoing evaluation by the US ...

Fluoroscopic assessment of the effects of commercially available spinal orthotics on lumbar vertebral motion as subjects performed flexion and extension maneuvers. To quantitate the effects of 3 commonly available, off-the-shelf, soft, and semirigid spinal orthoses on lumbar spinal motion. Commercially available soft and semirigid orthoses are widely prescribed for patients ...

STUDY DESIGN: An in vitro biomechanical study of the effectiveness of halo-vest fixation. OBJECTIVE: The objective was to evaluate motion of the injured cervical spine with normal halo-vest application and vest loose in the prone and supine positions. SUMMARY OF BACKGROUND DATA: Snaking motion of the neck is defined as ...

INTRODUCTION: Military aviators are susceptible to spinal injuries during high-speed ejection scenarios. These injuries commonly arise as a result of strains induced by extreme flexion or compression of the spinal column. This study characterizes the vertebral motion of two postmortem human surrogates (PMHS) during a simulated catapult phase of ejection ...

STUDY DESIGN: Clinical measurement, validity and intrarater reliability study. OBJECTIVES: (1) To confirm the validity and assess between-day test-retest reliability of cervical spine motion measurements made with the cervical range of motion (CROM) device in flexion, extension, bilateral rotation, and bilateral side flexion; (2) to provide meaningful information to clinicians ...

Proper management of cervical spine injuries in men's lacrosse players depends in part upon the ability of the helmet to immobilize the head. To determine if properly and improperly fitted lacrosse helmets provide adequate stabilization of the head in the spine-boarded athlete. Crossover study. Sports medicine research laboratory. Eighteen healthy ...

The role of torsion in the mechanical derangement of intervertebral discs remains largely undefined. The current study sought to investigate if torsion, when applied in combination with flexion, affects the internal failure mechanics of the disc wall when exposed to high nuclear pressure. Thirty ovine lumbar motion segments were each ...

STUDY DESIGN: Biomechanics of normal vertebral segments adjacent to a degenerated segment in the cervical spine. OBJECTIVE: To test the hypothesis of higher motion changes in the segment immediately inferior to a degenerated segment. SUMMARY OF BACKGROUND DATA: Past research has shown how disc degeneration (DD) affects adjacent segments; however, ...

To evaluate clinical targeting precision and assess patient movement data during fiducial-free, single-fraction spinal radiosurgery with the Cyberknife (CK). Image-guided spine tracking accuracy was tested using two phantoms. Movement patterns (three translations, roll, pitch and yaw) were obtained from log files of 260 patient treatments (47 cervical, 89 thoracic, 90 ...

Lumbar vertebrae are complicated in structure and function. The purpose of this study was to investigate the in-vivo motion characteristics of different portions of the lumbar vertebrae during functional activities. Motion of L2, L3 and L4 was reproduced using a combined dual fluoroscopic and MR imaging technique during flexion-extension and ...

STUDY DESIGN: Prospective clinical study. OBJECTIVE: The purpose of this investigation was to quantify normal lumbar range of motion (ROM) and compare these results with those used to perform 15 simulated activities of daily living (ADLs) in asymptomatic subjects. SUMMARY OF BACKGROUND DATA: Previous studies reporting the ROM of the ...

STUDY DESIGN: Reliability of clinical measurements over time. OBJECTIVES: To determine the long-term stability and minimal detectable change (MDC) of the flexion-rotation test (FRT) measurements over days in subjects with cervicogenic headache (CGH). BACKGROUND: The FRT is used by physical therapists to assist in identifying upper cervical movement impairment, as ...

BACKGROUND CONTEXT: Previous research has quantified cervical spine motion with conventional measurement techniques (eg, cadaveric studies, motion capture systems, and fluoroscopy), but these techniques were not designed to accurately measure three-dimensional (3D) dynamic cervical spine motion under in vivo conditions. PURPOSE: The purposes of this study were to characterize the ...

Mochokidae are able to produce pectoral spine stridulation sounds. During sound production, high speed videos were used to study the pectoral fin movements to identify the mechanisms involved. A call consisted of a series of pulses and occurred during a spine sweep, which was in fact made up of a ...

BACKGROUND: The main functions of the cervical spine are the stabilization and the orientation of the head. Pathologies are complex and difficult to diagnose. The first sign of the dysfunction is an abnormal intervertebral motion. It is the purpose of this feasibility study to determine the intersegmental motions and loading ...

Structurally, the sacrum-coccyx provides the dual roles of serving as the base of the spinal column while also forming part of the pelvic ring. Physiological movement control of the pelvis and the spine are functionally interdependent. In particular, intra-pelvic control, (that between the ilia and sacrum/coccyx in support and control ...

The craniovertebral junction is a complex region that incorporates the occiput-C1-C2 portions of the spine. It is a transition between the cranium and the mobile cervical spine that permits significant motion. The motions afforded and the anatomy are vastly different at the occiput-C1 and C1-C2 articulations. These differences make treating ...

In the prehospital setting, spine-injured patients must be transferred to a spine board to immobilize the spine. This can be accomplished using both manual techniques and mechanical devices. The study aimed to evaluate the effectiveness of the scoop stretcher to limit cervical spine motion as compared to 2 commonly used ...

Enzymatic treatments were applied to rat motion segments to establish structure-function relationships and determine mechanical parameters most sensitive to simulated remodeling and degeneration. Rat caudal and lumbar disc biomechanical behaviors were evaluated to improve knowledge of their similarities and differences due to their frequent use during in vivo models. Caudal ...

INTRODUCTION: When decompression of the lumbar spinal canal is performed, segmental stability might be affected. Exactly which anatomical structures can thereby be resected without interfering with stability, and when, respectively how, additional stabilization is essential, has not been adequately investigated so far. The present investigation describes kinetic changes in a ...

STUDY DESIGN: Prospective clinical study. OBJECTIVE: The purpose of this investigation was to quantify normal cervical range of motion (ROM) and compare these results to those used to perform 15 simulated activities of daily living (ADLs) in asymptomatic subjects. SUMMARY OF BACKGROUND DATA: Previous studies looking at cervical ROM during ...

The Range of Motion (ROM) is a popular measurement used in the determination of disability for low back pain subjects in spite of serious objections to its clinical usefulness. It is proposed to consider a different index called the Range of Normality (RON) which is defined to be the portion ...

Despite years of extensive research, the etiology of idiopathic scoliosis still has not been resolved. A hypothesis on the role of posteriorly directed shear loads was studied in several biomechanical and imaging studies. So far, it has been shown that: on the human erect spine these posteriorly directed shear loads ...

STUDY DESIGN: Biomechanical study of the ProDisc-L in a cadaveric model under pure moment loading. OBJECTIVE.: To determine the kinematic properties of a lumbar spine motion segment and the adjacent level following ProDisc-L disc replacement in the cadaveric spine. SUMMARY OF BACKGROUND DATA: Total disc replacement is intended to preserve ...

OBJECTIVE: Sitting has been identified as a cause of mechanical low back pain. The purpose of this study was to use plain film x-rays to measure lumbar spine and pelvic posture differences between standing and sitting. METHODS: Eight male subjects were radiographed standing and sitting in an automobile seat. Measures ...

Human bipedalism appears to be a prerequisite for the development of idiopathic scoliosis. The objective of this study was to examine the effect of different positions of the human spine on vertebral rotation in vivo. Thirty asymptomatic volunteers underwent MRI scanning of the spine in three different body positions; upright, ...

The internal forces in the human body in motion could provide valuable information for the evaluation and follow-up of subjects with musculo-skeletal pathologies, such as scoliosis, but are still difficult to accurately measure. In this context, the objective of this study is to quantify the global intervertebral torques along the ...

Bracing concepts in use today for the treatment of scoliosis include symmetric and asymmetric hard braces usually made of polyethylene (PE) and soft braces. The plaster cast method worldwide seems to be the most practiced technique for the construction of hard braces at the moment. CAD (Computer Aided Design) systems ...

Quantifying the kinematics of the human spine during a frontal impact is a challenge due to the multi-degree-of-freedom structure of the vertebral column. This papers reports on a series of six frontal impacts sled tests performed on three Post Mortem Human Surrogates (PMHS). Each subject was exposed first to a ...

The purpose of this study was to analyze kinematic trunk motion data in normal adults and to investigate gender effect. Kinematic trunk motion data were obtained for 20 healthy subjects (11 men and 9 women; age from 21 to 40 years) during walking a 9 m long lane at a ...

Proper modeling of the human trunk requires a quantitative assessment of the stiffness of the costovertebral joints. Twelve samples (adjacent thoracic vertebrae and one rib segment) were harvested from three subjects. The ribs were loaded in the cranial-caudal direction, the ventral-dorsal direction and in torsion around the cervical rib axis. ...

Lumbosacral orthoses (LSOs) are class I medical devices that are used in conservative and postoperative management of low back pain. The effectiveness of LSOs depends on their design aimed at enhancing trunk stiffness. Therefore, the purpose of this study was to compare two lumbar supports: extensible (made of neoprene and ...

OBJECT: The artificial disc has been proposed as an alternative to spinal fusion for degenerative disc disease. The primary aim of this biomechanical study was to compare motion and intradiscal pressure (IDP) in a ball-and-socket artificial disc-implanted cadaveric lumbar spine, at the operative and adjacent levels, using a displacement-controlled setup. ...

The report presents measurements of axial rotation of lumbar motion segments (L1/L2, L3/L4, L4/L5), particularly with small angles of rotation (in the range of +/-1 degrees) following axial force wrenches. The investigation focussed on determining the influence of geometrically varying configurations in axial wrench (consisting of axial torque and axial ...

STUDY DESIGN: Prospective clinical study. OBJECTIVE: To compare the amount of segmental motion in the sagittal plane after lumbar total disc arthroplasty (TDA) measured by using the Cobb technique, quantitative motion analysis (QMA), and radiostereometric analysis (RSA). SUMMARY OF BACKGROUND DATA: The aim of TDA is preservation of motion and ...

A three-dimensional finite element model of the spine T12-S1 segment was developed and used to investigate biodynamics characteristics of the human lumbar spine. The T12-S1 model was carefully built including spinal vertebrae, intervertebral discs, and ligaments so as to approach the real human spine. Finite element modal analysis was carried ...

Spinal loading in excessive and repeated trunk flexion may hinder recovery from acute low back pain. The Spineangel device provides real-time patient biofeedback on trunk flexion and may facilitate recovery from lower back injury. This cross-sectional study evaluates validity and reliability of this device in the laboratory setting. Participants included ...

OBJECTIVE: To better characterize both ocular and cervical vestibular evoked myogenic potentials (VEMP) responses at different frequencies of sound in 20 normal subjects. METHODS: Cervical and ocular VEMPs were recorded. The intensities of sound stimulation decreased from the maximal intensity, until no responses were evoked. Thresholds, amplitudes, latencies and interaural ...

OBJECT: Few biomechanical in vitro studies have reported the effects of disc replacement on motion and kinematics of the cervical spine. The purpose of this study was to analyze motion through 3D load-displacement curves before and after implantation of a ball-and-socket cervical disc prosthesis with cranial geometric center; special focus ...

The study design is a prospective, case-control. The aim of this study was to develop a reliable measurement technique for the assessment of lumbar spine kinematics using digital video fluoroscopy in a group of patients with low back pain (LBP) and a control group. Lumbar segmental instability (LSI) is one ...

The authors investigated the effect of lumbar facet tropism (FT) on intervertebral disc degeneration (DD), facet joint degeneration (FJD), and segmental translational motion. Using kinetic MRI (KMRI), lumbar FT, which was defined as a difference in symmetry of more than 7 degrees between the orientations of the facet joints, was ...

STUDY DESIGN: Retrospective radiographic review. OBJECTIVE: To investigate the effects of cervical disc herniation on kinematics at adjacent vertebral motion segments. SUMMARY OF BACKGROUND DATA: Kinetic magnetic resonance imaging (kMRI) is an alternative method to conventional MRI, which allows evaluation of the cervical spine in a more physiologic, weight-bearing position, ...

STUDY DESIGN: Prospective fluoroscopic and electromyographic study of coronal plane lumbar spine motion in healthy male volunteers. OBJECTIVES: Assess the intervertebral motion profiles in healthy volunteers for symmetry, regularity, and neutral zone laxity during passive recumbent lateral bending motion. SUMMARY OF BACKGROUND DATA: Previous continuous in vivo motion studies of ...

STUDY DESIGN: Hydrostatically induced disruption of flexed lumbar intervertebral discs followed by microstructural investigation. OBJECTIVE: To investigate how flexion affects the anulus' ability to resist rupture during hydrostatic loading, and determine how the characteristics of the resulting disc failures compare with those observed clinically. SUMMARY OF BACKGROUND DATA: While compression ...

STUDY DESIGN: A detailed three-dimensional finite element model of the spine segment T12-Pelvis was developed to investigate dynamic characteristics of whole lumbar spine with injured cases. OBJECTIVE: This study investigates the motion mechanism of the human lumbar spine and the effect of component injuries on adjacent spinal components under whole ...

STUDY DESIGN: Controlled laboratory study. OBJECTIVE: To measure the range of motion of lumbar facet (zygapophyseal) joints in vivo during various functional weight-bearing positions of the upper body. SUMMARY OF BACKGROUND DATA: Determination of normal in vivo motion of the lumbar facet joints remains elusive despite numerous in vitro studies, ...

STUDY DESIGN: An experimental in vivo ovine model of intervertebral disc degeneration was used to quantify the dynamic motion response of the lumbar spine. OBJECTIVE: The purpose of this study was to: (1) compare invasively measured lumbar vertebral bone acceleration responses to noninvasive displacement responses, and (2) determine the effects ...