The cervical spine ligaments play an essential role in limiting the physiological ranges of motion in the neck; however, traumatic loading such as that experienced in automotive crash scenarios can lead to ligament damage and result in neck injury. The development of detailed finite element models for injury simulation requires accurate ligament mechanical properties at relevant loading rates. The objective of this research was to provide detailed mechanical properties for the cervical spine ligaments, by performing tensile tests at elongation rates relevant to automobile crash scenarios, using younger specimens (less than 50 years old), and to provide a comprehensive investigation of spinal level and gender effects. The five primary ligaments (present between C2-T1) investigated were: the anterior longitudinal ligament, posterior longitudinal ligament, capsular ligament, ligamentum flavum, and interspinous ligament. The craniovertebral ligaments (Skull/C0-C2) investigated were the tectorial membrane/vertical cruciate/apical/alar ligament complex, transverse ligament, anterior atlanto-occipital membrane, posterior atlanto-occipital membrane, anterior atlanto-axial membrane, and posterior atlanto-axial membrane. Tests were performed within an environmental chamber designed to mimic in vivo temperature and humidity conditions, and specimens were preconditioned for 20 cycles at 10% strain prior to testing to failure. Ligaments were tested at quasi-static (0.5s-1), medium (20s-1) and high (150-250s-1). These strain rates were predicted by an existing cervical spine finite element model under typical crash scenarios. Two hundred sixty-one total primary ligament tests were performed, with approximately even distribution within elongation rate, spinal level, and gender. Another forty-four craniovertebral ligaments were tested. Results were plotted as force-displacement curves and the response characteristics determined from the curves were: failure force, failure elongation, stiffness of the linear region, toe region elongation, failure stress, failure strain, modulus and toe region strain. The measured force-displacement data followed expected trends when compared with previous studies. The younger ligaments had less scatter, and were both stiffer and stronger than the older specimens that were reported in previous studies at both quasi-static and comparable higher elongation rates. Statistical analysis was performed on the results to establish significant effects. Strain rate effects were most significant whereas spinal level effects were not found. In general, gender effects were not found to be significantly different, but consistent trends were identified with male ligaments having a higher stiffness and failure force than female ligaments. The post-ultimate load region of the curves was reported to offer insight into the ligament failure mechanism. The characteristic values obtained were used to develop average curves for each ligament, with the intention to eventually be directly integrated into finite element models to better represent the ligament structures. Curves were developed to incorporate the strain rate, spinal level and gender effects for each ligament based on the statistical analyses. Post-failure response was incorporated into these curves because this region has been shown to have an effect on neck behaviour in mathematical models. Recommendations for future studies include measuring accurate cross sectional areas of ligaments during tensile testing to obtain true stress and true strain measurements to better understand if differences in mechanical properties are structural or material. Other possible improvements would be further testing of young cervical spine ligaments with larger sample sizes to further explore spinal level and gender effects. Additional testing performed under identical testing conditions as the current study would allow for pooling of the results effectively increasing the sample size.

Im Rahmen der szintigraphischen Untersuchung der Halswirbelsäule gibt es unterschiedliche Aussagen zum physiologischen Speicherungsverhalten, insbesondere der kaudalen Facettengelenke. Eine Objektivierung der Szintigramme und Ermittlung von Normalbereichen der entsprechenden Speicherquotienten ist daher wichtig und stellt das Ziel dieser Arbeit dar. Zur Untersuchung kamen dafür 31 Pferde, bei denen es sich um Patienten der Chirurgischen Tierklinik in Leipzig aus dem Jahr 2008 handelte. Falls bei einem Pferd eine Lahmheit der Vordergliedmaße vorhanden war, wurde mit Hilfe der klinischen und szintigraphischen Untersuchung, sowie mittels diagnostischer Anästhesien als deren Ursache die Halswirbelsäule ausgeschlossen. Alle Pferde wiesen eine freie Beweglichkeit des Halses in alle Richtungen auf. Zur Bildung von Speicherquotienten wurden die als Interessenareale dienenden Facettengelenke C3/C4 bis C7/Th1, sowie der Wirbelkörper des sechsten Halswirbels zu verschiedenen Referenzarealen ins Verhältnis gesetzt. Als Referenzareale wurden dabei der Wirbelkörper des dritten und des vierten Halswirbels, sowie das auch als Interessenareal dienende Facettengelenk C3/C4 getestet. Anschließend wurden Normalbereiche für die Speicherquotienten ermittelt. Nach sonographischer Muskeldickenmessung über den Facettengelenken wurden deren Speicherquotienten mit Hilfe einer Formel auf einen Nullwert korrigiert, und für diese korrigierten Werte wurden ebenfalls Normalbereiche ermittelt. Es zeigte sich, dass die Speicherquotienten nach der Muskeldickenkorrektur gegenüber den nativen Speicherquotienten eine größere Streuung aufwiesen und somit größere und ungenauere Normalbereiche hervorbrachten. Dementsprechend sollten die nativen Speicherquotienten bevorzugt werden. Als das am besten geeignete Referenzareal für die Interessenareale C4/C5 bis C7/Th1 erweist sich hierbei die Isokontur-ROI auf dem Facettengelenk C3/C4. Für das Interessenareal C3/C4 eignet sich sowohl der Vergleich mit dem Referenzareal C3, als auch der mit dem Referenzareal C4. Das Interessenareal auf dem Wirbelkörper C6 wird am besten zum Referenzareal C4 ins Verhältnis gesetzt. Hervorzuheben sind die nativen Werte der Normalbereiche für die Gelenke C5/C6 und C6/C7, da hier am häufigsten röntgenologische Veränderungen zu finden sind. Sie betragen für das Gelenk C5/C6 auf der linken Halsseite 0,82-1,10 und auf der rechten Halsseite 0,86-1,10. Für das Gelenk C6/C7 beträgt der Normalbereich für die linke Halsseite 0,75-1,23 und für die rechte Halsseite 0,81-1,17. Zusammenfassend ist zu sagen, dass die quantitative Auswertung mittels der „Regions of Interest“-Technik an der Halswirbelsäule durchaus möglich ist und mit dieser Arbeit akzeptable Normalbereiche für die Facettengelenke C3/C4 bis C7/Th1 und für den Wirbelkörper C6 ermittelt werden konnten. Es fehlen nun noch Werte von Pferden mit einer klinischen Halswirbelsäulenproblematik, um die Aussagekraft der hier ermittelten Normalbereiche zu überprüfen.

The research described in this thesis focuses on the biomechanics of cervical spine injury diagnosis and rehabilitation management. This research is particularly relevant to the diagnosis of minor neck injuries that typically arise from motor vehicle accidents and are classified as "whiplash injuries". The diagnosis and treatment of these chronic neck problems has been particularly difficult and frustrating and these difficulties prompted calls for the objective evaluation of the techniques and procedures used in the measurement and assessment of neck dysfunction. The biomechanical aspects of the clinical diagnosis of minor cervical spine injuries were investigated in this work by reconfiguring an existing detailed biomechanical model of the human neck to simulate injuries to particular structures, and to model abnormal muscle activation. The investigation focused on the range of motion assessment and the methods of testing and rehabilitating the function of the deep neck muscles because the model could be applied to provide further insight into these facets of neck injury diagnosis and management. The de Jager detailed head-neck model, available as a research tool from TNO (The Netherlands), was chosen for this study because it incorporated sufficient anatomical detail, but the model required adaptation because it had been developed for impact and crash test dummy simulations. This adaptation significantly broadened the model's field of application to encompass the clinical domain. The facets of the clinical diagnosis of neck dysfunction investigated in this research were range of motion and deep muscle control testing. Range of motion testing was simulated by applying a force to the head to generate the primary motions of flexion/extension, lateral flexion and axial twisting and parametric changes were made to particular structures to determine the effect on the head-neck movement. The main finding from this study of cervical range of motion testing was that while motion can be accurately measured in three dimensions, consideration of the three dimensional nature of the motion can add little to the clinical diagnosis of neck dysfunctions. Given the non-discriminatory nature of range of motion testing, the scientific collection and interpretation of the three dimensional motion patterns cannot be justified clinically. The de Jager head-neck model was then further adapted to model the cranio-cervical flexion test, which is used clinically to test the function of the deep muscle groups of the neck. This simulation provided confirmation of the efficacy of using a pressure bio-feedback unit to provide visual indication of the activation of the deep flexor muscles in the neck. However, investigation of the properties of the pressure bio-feedback unit identified significant differences in the stiffness of the bag for the different levels of inflation that must be accounted for if comparisons are to be made between subjects. Following the identification of the calibration anomalies associated with the pressure bio-feedback unit, the motion of the point of pressure of the head on the headrest and the force at this point of contact during the activation of the deep flexor muscle group were investigated as an alternative source of feedback. This output, however, was found to be subject specific, depending on the posterior shape of the skull that determined the point of contact during the head rolling action. Clinically, an important outcome of the alternative feedback assessment was that the prescribed action to target the deep flexor muscle group will feel different for each individual, ranging from a slide to a roll of the head on the headrest, and this must be accounted for when explaining the action and during rehabilitation management.

Bioimpedance spectroscopy has shown potential as a method for characterising biological tissue with the use of a tetrapolar electrode configuration. Brown et al. (2000) demonstrated that the configuration is capable of distinguishing between normal squamous epithelium and Cervical Intra-epithelial Neoplasia (CIN). However little has been done to identify the volumes of tissue that contribute to the measured impedance. Brown et al. employed a probe with a single tetrapolar electrode set thus analysing single points of tissue. The probe was required to be moved in order to "sample" other areas of tissue. This method provides no spatial information of the lesion boundaries. The overall objective of this research was to design and construct an impedance mapping system (IMS) for objective virtual biopsy of lesions by bioimpedance spectroscopy (BIS). Initially freshly excised cervical tissue was to be tested however as the study progressed this proved problematic and bovine blood was chosen as a suitable substitute. Specific aims were to; - .Investigate the spatial sensitivity distribution of the tetrapolar electrode configuration via finite element analysis (FEA). - Design a novel front end multiplexing system and multi-electrode array for mapping the impedance of the tissue of interest. - .Experimentally confirm the efficacy of the approach to identify regions of different impedances and their boundaries using bioimpedance mapping. The present study used finite element analysis (FEA) to investigate the spatial variation in sensitivity of the tetrapolar electrode configuration and identify which volumes of tissue were included in the measured impedance. An impedance mapping device was also designed and constructed utilising the tetrapolar electrode configuration in an expanded array of 25 electrodes. This array allowed the surface of an area of tissue to be mapped and lesion boundaries identified in an objective manner. FEA was also used to model lesions in healthy tissue and the sensitivity fields associated with the tetrapolar configuration. The FEA indicated that anomalous results would be obtained when a lesion was located between a drive and measurement electrode pair. In this case the lesion resulted in an increase in impedance with respect to the impedance of healthy tissue, whereas a lesion should result in a decrease in measured impedance relative to that of healthy tissue. The anomaly was found to produce false negative results for small lesions up to 0.4 mm and even a lesion with radius of approximately 0.75 mm could be undetected as the measured impedance spectrum for such a lesion is similar to that of healthy tissue. Modelling also provided insight into the sensitivity fields for an electrode array and its efficacy in accurately measuring the surface impedance of tissue and lesions of interest. The impedance mapping system (IMS) developed used an array of 25 (5x5) electrodes. The array allows 64 individual tetrapolar measurements to be obtained at 16 locations, providing an impedance map of 49 mm2 on the surface of a tissue sample. Multiple measurements at each location reduce the chance of anomalous results since these can be identified and excluded. Software was developed to display the measured impedance maps and regions of different impedance were easily identified Testing of the IMS using bovine blood showed separation of the measured impedance for a range of haematocrit between 0 - 80%. Introduced volumes of red blood cells (RBC) or clots (to mimic lesions) to the plasma (haematocrit 0%) were also clearly identified using the IMS. It was seen that measurements made at the boundary of 2 different haematocrits (ie 2 volumes of different impedance) resulted in an anomalous result as indicated by the FEA modelling. However it was demonstrated that these anomalies can be used to objectively identify the introduced RBC (lesion) boundaries. A more efficient electrode stepping sequence was also developed taking advantage of the reciprocal nature of the tetrapolar electrode configuration. This development allows for the electrode array to be doubled in size using the same components, and to sample twice the surface area in the same time taken using the initially developed system. In summary, an impedance mapping system has been modelled, designed and developed for tissue characterisation by bioimpedance measurements. The technique has been shown experimentally to be able to detect regions of differ- ent impedance and is in agreement with the finite element analysis performed. Further development of the IMS will allow progressive monitoring of suspect lesions in-vivo and better identification of their spatial distribution for biopsy.

Background: Headache is common in the elderly. Cervical degenerative changes are universal with ageing and cervicogenic headache is proposed (albeit without evidence) as a frequent cause of headache in this age group. Previous research identified a pattern of cervical musculoskeletal impairment which differentiated cervicogenic headache from other frequent headaches but this study was undertaken on younger/middle aged individuals. The value of this diagnostic pattern could be questioned for an older population with concomitant age related changes in the musculoskeletal system. The first and foremost aim of this research was to determine if cervical musculoskeletal impairment was specific to headaches classifiable as cervicogenic or was more generic to headache in elders. Participants with headache were sub-grouped on the basis of the pattern of cervical musculoskeletal impairment and the relationship between this grouping and headache classification was investigated. The presence of sensory hypersensitivity and psychological distress are features of headache that can provide information on the underlying mechanisms and provide management directives for headache. There is little knowledge of whether or not these features are influenced by a factor of age. Thus the second and third aims of this research were to investigate sensory features and psychological and quality of life features in the elderly with headache. Methods: One hundred and eighteen subjects, aged 60 to 75 years with recurrent headache and 44 controls were studied. Ninety-three reported a single headache and 25, two or more headache types. All subjects completed the Neck Disability Index (NDI), Geriatric Depression Scale-short form (GDS-S) and SF-36 questionnaires. Subjects with headache also completed a headache questionnaire and the Survey of Pain Attitudes (SOPA-35). Neck function measures included range of motion, manual examination of cervical segments, cranio-cervical flexor muscle function, joint position sense, cervical muscle strength, cross-sectional area of selected cervical extensors and posture. Sensory measures included pressure pain thresholds (PPTs) and thermal pain thresholds (TPTs). PPTs were measured over the forehead, upper neck and at a remote site (tibialis anterior). TPTs were measured over the upper neck. Results: Cluster analysis, based on the three musculoskeletal variables aligned previously with cervicogenic headache, divided headache subjects into two groups; cluster 1 (n = 57), cluster 2 (n = 50). There was significantly reduced cervical extension, axial rotation, rotation in neck flexion and lateral flexion in the headache clusters than the control group, and in the frequency of symptomatic joint dysfunction (C0-1 – C7-T1) (all p < 0.05). Subjects in cluster 1 had significantly reduced range of cervical extension and axial rotation and frequency of symptomatic joint dysfunction (C1-2 and C7-T1) compared to those in cluster 2 and controls (all p < 0.05). More subjects in cluster 1 had headaches ≥ 15 days per month and histories of head/neck trauma (both p < 0.05). Most cervicogenic headaches were grouped in cluster 1, but musculoskeletal dysfunction was also found in headaches classifiable as migraine or tension-type headache. The analysis of subjects with single headaches revealed no significant differences between the headache groups (migraine, tension-type, cervicogenic and unclassifiable headaches) and controls in pressure and cold pain thresholds (all p > 0.05). Heat pain thresholds were significantly lower in the headache groups compared to controls (all p < 0.01) but there were no differences between headache types (all p > 0.05). There were no strong relationships between any headache variable and pain thresholds. Elders with headache scored lower on most SF-36 domains, higher on the GDS-S (p < 0.05) and comparably on the SOPA-35 (p > 0.05) compared to the control group. The GDS score was below the threshold value for depression. Differences in these measures were not dependent on the headache types but rather, headache frequency. Subjects with headaches ≥ 15 days/month scored lowest on SF-36 domains and highest on GDS-S questionnaire compared to those with headache < 15 days/month and controls (all p < 0.05). The mean NDI score in the subjects with headache indicated the presence of mild to moderate neck pain and disability. No strong relationships were found between well-being and headache frequency, intensity and length of headache history. The NDI score had the greatest influence on physical well-being and GDS-S score on mental well-being (p < 0.001). Conclusions: Several aspects of cervical musculoskeletal function, heat thresholds, general well being and quality of life were altered in elders with headache. Neck dysfunction was not uniquely confined to cervicogenic headache but was a generic feature of headache in the elderly. No generalized changes in pain sensitivity were present in elders with headache. Headache had a significant impact on elders’ quality of life but was not associated with depression. Neck pain was an important factor influencing function and well-being. Conservative management such as physiotherapy may be a safe and appropriate option for elders with headache, given its frequent association with cervical musculoskeletal impairment. Further research is required for a better understanding of the neck’s role in elders’ headache.

No description available.

[Abstract not available]

Thesis (M.CM)--Hong Kong Baptist University, 2006. / Dissertation submitted to the School of Chinese Medicine. Includes bibliographical references (leaves 31-38).

Thesis (M.CM)--Hong Kong Baptist University, 2006. / Dissertation submitted to the School of Chinese Medicine. Includes bibliographical references (leaves 29-31).

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.