M.Tech.

Cervical Spine injuries are a common occurrence during motor vehicle accidents, and they represent a significant economic cost to society. Numerical Finite Element (FE) models have been formulated to investigate the response of the neck under various loading scenarios and to improve vehicle safety. The Global Human Body Models Consortium (GHBMC) was formed to develop a detailed FE model capable of simulating occupant response and predicting subsequent soft tissue injuries in the cervical spine. The objective of this thesis was to validate the neck region of the GHBMC model at the segment level in flexion and extension, and at rotation rates observed during car crash scenarios. Nine cervical spines, under the age of 50, were procured from post mortem human subjects and they were dissected into segments. A segment consisted of two vertebrae with the ligaments and the intervertebral disc intact, and the muscle, nervous, and cardiovascular tissues removed. A custom built fixture was built to test each specimen three times in flexion and extension at two rotation rates: a low rate (one degree per second) and a high rate (500 degrees per second). To avoid damaging the specimens after the first test, the segments were only rotated up to ten degrees for the segments at the C2-C3 through C5-C6 level, and up to eight degrees for the C6-C7 and C7-T1 level. The segment response was represented by plots of the moment against the angle of rotation in the sagittal plane. The segment models were simulated at the same low and high rotation rates, and the model results were evaluated against the experimental response. The low speed experimental results were compared to existing quasi-static studies, but there was not an elevated rotation rate study at each segment level to compare with the high rate response. The segment response from the existing data was generally weaker than the results of this thesis because the earlier studies tested older specimens, and the exiting studies applied a step-wise loading protocol instead of a continuous one. A statistical analysis was conducted to determine the significance of the difference between the low and high rate experimental response. At the maximum angle of rotation, the analysis found moderate evidence (p < 0.05) of increased segment stiffness at the high rotation rate for the C5-C6 and C6-C7 segments in flexion and extension, and weak evidence of increased stiffness for the C3-C4 and C4-C5 segments in flexion and extension, and for the C2-C3 and C7-T1 segments in extension. Below six degrees of rotation, there was no statistical evidence that the low and high speed responses were significantly different for any segment. In flexion, the model response was within one standard deviation of the experimental mean at the C6-C7 and C7-T1 segment level. For the C2-C3 through C5-C6 segment levels, the model was stiffer than the experimental mean. In extension, the model was within one standard deviation at every segment level except at the C2-C3 and C7-T1 segment levels where the model response was weaker than the experimental response. For the high rate model analysis, the model predicted that the high rate simulations were stiffer than the low rate simulation at every segment level; however the difference was much greater in flexion than in extension. Recommendations for further research included studying the high rate behaviour of the intervertebral discs under compressive and bending loading, and investigating the translational and rotational displacement of the spine during flexion and extension and compare the results with the model. The procurement of more post mortem human subjects would increase the sample size and it could improve the significance of the statistical analysis, and additional spines would permit the analysis of other effects, such as the influence of gender.

Cervical Spine injuries are a common occurrence during motor vehicle accidents, and they represent a significant economic cost to society. Numerical Finite Element (FE) models have been formulated to investigate the response of the neck under various loading scenarios and to improve vehicle safety. The Global Human Body Models Consortium (GHBMC) was formed to develop a detailed FE model capable of simulating occupant response and predicting subsequent soft tissue injuries in the cervical spine. The objective of this thesis was to validate the neck region of the GHBMC model at the segment level in flexion and extension, and at rotation rates observed during car crash scenarios. Nine cervical spines, under the age of 50, were procured from post mortem human subjects and they were dissected into segments. A segment consisted of two vertebrae with the ligaments and the intervertebral disc intact, and the muscle, nervous, and cardiovascular tissues removed. A custom built fixture was built to test each specimen three times in flexion and extension at two rotation rates: a low rate (one degree per second) and a high rate (500 degrees per second). To avoid damaging the specimens after the first test, the segments were only rotated up to ten degrees for the segments at the C2-C3 through C5-C6 level, and up to eight degrees for the C6-C7 and C7-T1 level. The segment response was represented by plots of the moment against the angle of rotation in the sagittal plane. The segment models were simulated at the same low and high rotation rates, and the model results were evaluated against the experimental response. The low speed experimental results were compared to existing quasi-static studies, but there was not an elevated rotation rate study at each segment level to compare with the high rate response. The segment response from the existing data was generally weaker than the results of this thesis because the earlier studies tested older specimens, and the exiting studies applied a step-wise loading protocol instead of a continuous one. A statistical analysis was conducted to determine the significance of the difference between the low and high rate experimental response. At the maximum angle of rotation, the analysis found moderate evidence (p < 0.05) of increased segment stiffness at the high rotation rate for the C5-C6 and C6-C7 segments in flexion and extension, and weak evidence of increased stiffness for the C3-C4 and C4-C5 segments in flexion and extension, and for the C2-C3 and C7-T1 segments in extension. Below six degrees of rotation, there was no statistical evidence that the low and high speed responses were significantly different for any segment. In flexion, the model response was within one standard deviation of the experimental mean at the C6-C7 and C7-T1 segment level. For the C2-C3 through C5-C6 segment levels, the model was stiffer than the experimental mean. In extension, the model was within one standard deviation at every segment level except at the C2-C3 and C7-T1 segment levels where the model response was weaker than the experimental response. For the high rate model analysis, the model predicted that the high rate simulations were stiffer than the low rate simulation at every segment level; however the difference was much greater in flexion than in extension. Recommendations for further research included studying the high rate behaviour of the intervertebral discs under compressive and bending loading, and investigating the translational and rotational displacement of the spine during flexion and extension and compare the results with the model. The procurement of more post mortem human subjects would increase the sample size and it could improve the significance of the statistical analysis, and additional spines would permit the analysis of other effects, such as the influence of gender.

The purpose of this study is to quantify the dynamic mechanical properties of human cervical ligaments following whiplash. Cervical ligaments function to provide spinal stability, propioception, and protection during traumatic events to the spine. The function of cervical ligaments is largely dependant on their dynamic biomechanical properties, which include force and energy resistance, elongation capability, and stiffness. Whiplash has been shown to injure human cervical spine ligaments, and ligamental injury has been shown to alter their dynamic properties, with potential clinical consequences such as joint degeneration and pain. In this study we quantified the dynamic properties of human lower cervical ligaments following whiplash and compared their properties to those of intact ligaments. Whiplash simulation was performed using biofidelic whole cervical spine with muscle force replication (WCS-MFR) models. Next, ligaments were elongated to failure at a fast elongation rate and peak force, peak elongation, peak energy, and stiffness values were calculated from non-linear force-elongation curves. Peak force was highest in the ligamentum flavum (LF) and lowest in the intraspinous and supraspinous ligaments (ISL+SSL). Elongation was smallest in middle-third disc (MTD) and greatest in ISL+SSL. Highest peak energy was found in capsular ligament (CL) and lowest in MTD. LF was the stiffest ligament and ISL+SSL least stiff. These findings were similar to those found in intact ligaments. When directly comparing ligaments following whiplash to intact ligaments in a prior study it was found that the anterior longitudinal ligament (ALL) and CL had altered dynamic properties that were statistically significant, suggesting that whiplash may alter the dynamic properties of cervical ligaments. These findings may contribute to the understanding of whiplash injuries and the development of mathematical models simulating spinal injury.

Multi-echo T2 relaxation measurements of the human spinal cord (SC) reveal a short T2 pool of water believed to arise from water trapped between myelin bilayers, where the proportion of this water to the total water signal is called the myelin water fraction (MWF). In the present study, MWF were measured in the healthy human cervical spine at the C4-C6 vertebral levels in vivo using a 3D modified 32 echo CPMG sequence to acquire axial slices perpendicular to the cord. Volunteers were recruited in two age ranges, under 30 years old and over 50 years old, and a subset of both groups were scanned twice to test reproducibility. Mean MWF in the dorsal and lateral column WM of the group under 30 years of age was 0.29 (0.01) (mean(SE)), which agrees with previously reported MWF values in the cervical spine. The mean absolute difference between two scans was 0.06 or 26%. A negative correlation between WM MWF and age was hinted at in these findings, however more subjects are required to improve statistical power. This study paves the way for the use of 3D myelin water imaging in the cervical spine at 3.0T for the assessment of SC WM pathology.

Multi-echo T2 relaxation measurements of the human spinal cord (SC) reveal a short T2 pool of water believed to arise from water trapped between myelin bilayers, where the proportion of this water to the total water signal is called the myelin water fraction (MWF). In the present study, MWF were measured in the healthy human cervical spine at the C4-C6 vertebral levels in vivo using a 3D modified 32 echo CPMG sequence to acquire axial slices perpendicular to the cord. Volunteers were recruited in two age ranges, under 30 years old and over 50 years old, and a subset of both groups were scanned twice to test reproducibility. Mean MWF in the dorsal and lateral column WM of the group under 30 years of age was 0.29 (0.01) (mean(SE)), which agrees with previously reported MWF values in the cervical spine. The mean absolute difference between two scans was 0.06 or 26%. A negative correlation between WM MWF and age was hinted at in these findings, however more subjects are required to improve statistical power. This study paves the way for the use of 3D myelin water imaging in the cervical spine at 3.0T for the assessment of SC WM pathology.

Multi-echo T2 relaxation measurements of the human spinal cord (SC) reveal a short T2 pool of water believed to arise from water trapped between myelin bilayers, where the proportion of this water to the total water signal is called the myelin water fraction (MWF). In the present study, MWF were measured in the healthy human cervical spine at the C4-C6 vertebral levels in vivo using a 3D modified 32 echo CPMG sequence to acquire axial slices perpendicular to the cord. Volunteers were recruited in two age ranges, under 30 years old and over 50 years old, and a subset of both groups were scanned twice to test reproducibility. Mean MWF in the dorsal and lateral column WM of the group under 30 years of age was 0.29 (0.01) (mean(SE)), which agrees with previously reported MWF values in the cervical spine. The mean absolute difference between two scans was 0.06 or 26%. A negative correlation between WM MWF and age was hinted at in these findings, however more subjects are required to improve statistical power. This study paves the way for the use of 3D myelin water imaging in the cervical spine at 3.0T for the assessment of SC WM pathology. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Background: Research suggests that cervical spine CT examination is over used for potential injury due to blunt trauma. Education of emergency providers regarding evidence-based guidelines can help reduce the over-use of CT examination, and the development of an evidence-based protocol for the management of patients with suspected cervical spine trauma may help promote more appropriate clinical use of radiologic imaging for cervical spine clearance. Purpose: The ultimate goal of this project is to develop a best-practice, evidence-based protocol for the management of patients with suspected cervical spine injury, in order to promote safe and efficient clinical clearance, as well as promote judicious and appropriate use of diagnostic imaging for suspected cervical spine injury. Methods: A retrospective chart review of emergency radiographic imaging studies obtained over a three-month timeframe for suspected cervical spine injury at a 300-bed hospital in Tucson, Arizona was performed to compare ordering practices with the ACR-AC. Descriptive statistics were used for data analysis. A web-based survey was conducted of facility stakeholders including emergency physicians, nurse practitioners and physician assistants regarding their views about clinical guidelines and protocols for radiographic and clinical clearance of cervical spine injury. Descriptive statistics and thematic analysis was used for survey responses. Results: Analysis of 263 imaging studies over a three-month timeframe demonstrated that 24.3% of cervical spine imaging studies obtained in three-month timeframe would be considered not appropriate based on the ACR-AC. The survey of emergency clinicians revealed that none of those who responded have a preference for referring to the ACR appropriateness criteria, and the majority of respondents did not support the implementation of a hospital protocol for the management of patients with suspected cervical spine trauma. Recommendations: An institutional protocol for suspected cervical spine injury developed from the ACR-AC with incorporation of clinical clearance criteria is recommended. To promote clinician acceptance, overcome resistance to implementation, and promote individualized patient care, the protocol should also include provider education and should allow for variance based on individual patient circumstances.

Author: Bc. Veronika Valášková Title of the work: The effect of physiotherapeutic procedures on cervical spine surgery. Aim: The aim of my thesis is to give an overview of the physiotherapy treatment after surgery of herniated cervical intervertebral disc. Methods: This thesis is written as a review of literature sources. The thesis consists of three parts, the first of which highlights the issue of kinesiology, biomechanics, stability of the cervical spine, pathophysiology of a prolapsed spinal disc and imaging issues involved in the discovery of a the actual prolapse. The second part deals with the various surgical techniques and associated complications. The final theoretical part looks into physiotherapy treatment after the operation. I examine the chronology of physiotherapy after the operation, and ascertain if there is a necessity to apply a neck brace after the surgery. It is important to answer the question of when it is possible to return to work and when the patient can return to their original physical activities. Results: The results of this thesis shows that postoperative care in individual departments vary and is inadequately described within available resources. Subsequent physiotherapy is dependent on the patient's condition before the operation, the operation itself, and its...

Injuries to the neck, or cervical region, are very importantsince there is a potential risk of damage to the spinal cord.Any neck injury can have devastating if not life threateningconsequences. High-speed transportation as well as leisure-timeadventures have increased the number of serious neck injuriesand made us increasingly aware of its consequences.Surveillance systems and epidemiological studies are importantprerequisites in defining the scope of the problem. Thedevelopment of mechanical and clinical tools is important forprimary prevention of neck injuries. Thus, the main objectives of the present doctoral thesisare:- To illustrate the dimension of cervical injuries inSweden,- To develop a Finite Element (FE) model of the uppercervical spine, and- To study spinal stability for cervical injuries. The incidence studies were undertaken with data from theinjury surveillance program at the Swedish National Board ofHealth and Welfare. All in-patient data from Swedish hospitals,ranging over thirteen years from 1987 to 1999, were analyzed.During this period 14,310 nonfatal and 782 fatal cervicalinjuries occurred. The lower cervical spine is the mostfrequent location for spinal trauma, although, this changeswith age so that the upper cervical spine is the most frequentlocation for the population over 65 years of age. The incidencefor cervical fractures for the Swedish population decreased forall age groups, except for those older than 65 years of age.The male population, in all age groups, has a higher incidencefor neck fractures than females. Transportation relatedcervical fractures have dropped since 1991, leaving fallaccidents as the sole largest cause of cervical trauma. An anatomically detailed FE model of the human uppercervical spine was developed. The model was validated to ensurerealistic motions of the joints, with significant correlationfor flexion, extension, lateral bending, axial rotation, andtension. It was shown that an FE-model could simulate thecomplex anatomy and mechanism of the upper cervical spine withgood correlation to experimental data. Three studies wereconducted with the FE model. Firstly, the model of the uppercervical spine was combined with an FE model of the lowercervical spine and a head model. The complete model was used toinvestigate a new car roof structure. Secondly, the FE modelwas used for a parameter study of the ligament materialcharacteristics. The kinematics of the upper cervical spine iscontrolled by the ligamentous structures. The ligaments have tomaintain spinal stability while enabling for large rotations ofthe joints. Thirdly, the FE-model was used to study spinalinjuries and their effect on cervical spinal stability inflexion, extension, and lateral bending. To do this, the intactupper cervical spine FE model was modified to implementruptures of the various spinal ligaments. Transection of theposterior atlantooccipital membrane, the ligametum flavum andthe capsular ligament had the most impact on flexion, while theanterior longitudinal ligament and the apical ligamentinfluenced extension. It is concluded that neck injuries in Sweden is a problemthat needs to be address with new preventive strategies. It isespecially important that results from the research on fallaccidents among the elderly are implemented in preventiveprograms. Secondly, it is concluded that an FE model of thecervical region is a powerful tool for development andevaluation of preventive systems. Such models will be importantin defining preventive strategies for the future. Lastly, it isconcluded that the FE model of the cervical spine can increasethe biomechanical understanding of the spine and contribute inanalyses of spinal stability.