Injury to the human neck is a frequent consequence of automobile accidents and has been a significant public health problem for many years. The term `whiplash' has been used to describe these injuries in which the sudden differential movement between the head and torso leads to abnormal motions within the neck causing damage to its soft tissue components. Although many different theories have been proposed, no definitive answer on the cause of `whiplash' injury has yet been established and the exact mechanisms of injury remain unclear. Biomechanical research is ongoing in the field of impact analysis with many different experimental and computational methods being used to try and determine the mechanisms of injury. Experimental research and mathematically based computer modelling are continually used to study the behaviour of the head and neck, particularly its response to trauma during automobile impacts. The rationale behind the research described in this thesis is that a computational model of the human head and neck, capable of simulating the dynamic response to automobile impacts, could help explain neck injury mechanisms. The objective of the research has been to develop a model that_,, can accurately predict the resulting head-neck motion in response to acceleration impacts of various directions and severities. This thesis presents the development and validation of a three-dimensional computational model of the human head and cervical spine. The novelty of the work is in the detailed representation of the various components of the neck. The model comprises nine rigid bodies with detailed geometry representing the head, seven vertebrae of the neck and the first thoracic vertebra. The rigid bodies are interconnected by spring and damper constraints representing the soft-tissues of the neck. 19 muscle groups are included in the model with the ability to curve around the cervical vertebrae during neck bending. Muscle mechanics are handled by an external application providing both passive and active muscle behaviour. The major findings of the research are: From the analysis of frontal and lateral impacts it is shown that the inclusion of active muscle behaviour is essential in predicting the head-neck response to impact. With passive properties the response of the head-neck model is analogous to the response of cadaveric specimens where the influence of active musculature is absent. Analysis of the local loads in the soft-tissue components of the model during the frontal impact with active musculature revealed a clear peak in force in the majority of ligaments and in the intervertebral discs very early in the impact before any forward rotation of the head had occurred. For the case of rear-end impact simulations it has been shown for the first time that the inclusion of active musculature has little effect on the rotation of the head and neck but significantly alters the internal loading of the soft-tissue components of the neck.

Developing computational models of the human spine has been a hot topic in biornechanical research for a couple of decades in order to have an understanding of the behaviour of the whole spine and the individual spinal parts under various loading conditions. The objectives of this thesis are to develop a biofidefic multi-body model of the whole human spine especially for dynamic analysis of impact situations, such as frontal impact in a car crash, and to generate finite element (FE) models of the specific spinal parts to investigate causes of injury of the spinal components. As a proposed approach, the predictions of the multi-body model under dynamic impact loading conditions, such as reaction forces at lumbar motion segments, were utilised not only to have a better understanding of the gross kinetics and kinematics of the human spine, but also to constitute the boundary conditions for the finite element models of the selected spinal components. This novel approach provides a versatile, cost effective and powerful tool to analyse the behaviour of the spine under various loading conditions which in turn helps to develop a better understanding of injury mechanisms.

Darbo tikslas – palyginti dviejų skirtingų kineziterapijos programų poveikį pacientų funkcinei būklei esant skausmui dėl juosmeninės stuburo dalies disko išvaržos. Uždaviniai: 1. Įvertinti kineziterapijos programos vandenyje efektyvumą: skausmui, funkcinei būklei, juosmens–dubens srities stabilumui ir judesių valdymui bei statinei liemens raumenų jėgos ištvermei. 2. Įvertinti kineziterapijos programos salėje efektyvumą: skausmui, funkcinei būklei, juosmens–dubens srities stabilumui ir judesių valdymui bei statinei liemens raumenų jėgos ištvermei. 3. Palyginti kineziterapijos vandenyje ir kineziterapijos salėje programų efektyvumą: skausmui, funkcinei būklei, juosmens–dubens srities stabilumui, judesių valdymui bei statinei liemens raumenų jėgos ištvermei. Metodai: 1. Literatūros šaltinių analizė. 2. Anketinė apklausa. 3. Skausmo intensyvumo vertinimas naudojant skaičių analogijos skalę (SAS). 4. Juosmens–dubens srities stabilumo vertinimas naudojant slėgio matavimo prietaisą su grįžtamuoju ryšiu „Stabilizer“. 5. Juosmens–dubens srities valdymo funkcijos įvertinimas 5 testų rinkiniu pagal Hannu Luomajoki. 6. Nugaros ir pilvo raumenų statinės jėgos ištvermės vertinimas statinės atlikties testais. 7. Testų atlikties filmavimas ir vaizdinės medžiagos analizė. 8. Matematinė statistinė analizė. Tyrimas atliktas VšĮ Vilkaviškio ligoninė. Tyrime dalyvavo 28 tiriamieji (16 moterų ir 12 vyrų), kurie atsitiktine tvarka buvo suskirstyti į dvi grupes: kineziterapija vandenyje (n=14) ir... [toliau žr. visą tekstą] / Aim: to study and to compare impact of different kinezitherapy programs on a functional state of a patient in case of pain due to spinal hernia of waistline. Objectives: 1. to assess the efficiency of kinezitherapy program in water in terms of pain, a functional state, stability of waist – coxa area , management of movements and stamina of static waist muscles’ power; 2. to assess the efficiency of kinezitherapy program in a gym in terms of pain, a functional state, stability of waist – coxa area , management of movements and stamina of static waist muscles’ power; 3. to compare the efficiency of kinezitherapy program in water and in a gym in terms of pain, a functional state, stability of waist – coxa area, management of movements and stamina of static waist muscles’ power. Methods: 1. Analysis of literature sources; 2. Questionnaire; 3. Pain efficiency assessment via the Digital Analog Scale (DAS); 4. Assessment of stability of waist – coxa area with a pressure measurement device with a feedback “Stabilizer“. 5. Assessment of waist – coxa area management function with 5 test kit of Hannu Luomajoki. 6. Assessment of static power stamina of back and abdominal muscles by static exercising tests. 7. Shooting of test exercising and analysis of video material. 8. Mathematical statistical analysis. Research has been conducted at the Public Enterprise Vilkaviškio ligoninė. A total number of respondents: 28 (16 females and 12 males), divided in two groups randomly: kinezitherapy... [to full text]

Degenerative disc disease is a common ailment with enormous medical, psychosocial and economic ramifications. This study was designed to investigate the utility of a thiol-modified hyaluronan(TMHA) and elastin-like polypeptide(EP) composite material as a potential tissue engineering scaffold to reconstitute the nucleus pulposus in early degenerative disc disease. TMHA and EP were combined in various concentrations and cross-linked using poly(ethylene glycol)diacrylate. Resulting materials were evaluated biomechanically and biologically. Confined compression testing revealed that the addition of EP to TMHA-based gels resulted in a stiffer construct, but remained an order of magnitude less stiff than native nucleus. The in vitro cell culture experiments with human intervertebral disc cells demonstrated 70% cell viability at three weeks with apparent maintenance of phenotype. The addition of EP did not have a significant biologic effect. An in vivo pilot study demonstrated biocompatibility of the TMHA-based hydrogels; additional power is required to adequately assess treatment effect.

Patients undergoing elective surgery typically fast for 8-12 hours before surgery. However, oral preoperative carbohydrate ingestion may increase postoperative insulin sensitivity and reduce complications. To determine the effects of carbohydrate supplementation prior to CABG or spinal surgery, 38 patients were randomized to receive a carbohydrate supplement or to fast for 12 hours preoperatively. Baseline and postoperative measurements of insulin sensitivity were completed using the short insulin tolerance test and homeostasis model assessment (HOMA). Patient discomfort was measured immediately before surgery. Insulin sensitivity was not significantly different between groups. However, the supplemented group experienced a significantly smaller rise in glucose levels following surgery (p=0.03) and had higher postoperative HOMA-β scores (p=0.02). Fasted patients were significantly more thirsty (p=0.01), hungry (p=0.04) and anxious (p=0.01) before surgery and experienced a significantly longer hospital stay (p=0.008). Carbohydrate supplementation improved outcomes, warranting re-evaluation of fasting practices prior to major surgery.

Degenerative disc disease is a common ailment with enormous medical, psychosocial and economic ramifications. This study was designed to investigate the utility of a thiol-modified hyaluronan(TMHA) and elastin-like polypeptide(EP) composite material as a potential tissue engineering scaffold to reconstitute the nucleus pulposus in early degenerative disc disease. TMHA and EP were combined in various concentrations and cross-linked using poly(ethylene glycol)diacrylate. Resulting materials were evaluated biomechanically and biologically. Confined compression testing revealed that the addition of EP to TMHA-based gels resulted in a stiffer construct, but remained an order of magnitude less stiff than native nucleus. The in vitro cell culture experiments with human intervertebral disc cells demonstrated 70% cell viability at three weeks with apparent maintenance of phenotype. The addition of EP did not have a significant biologic effect. An in vivo pilot study demonstrated biocompatibility of the TMHA-based hydrogels; additional power is required to adequately assess treatment effect.

Patients undergoing elective surgery typically fast for 8-12 hours before surgery. However, oral preoperative carbohydrate ingestion may increase postoperative insulin sensitivity and reduce complications. To determine the effects of carbohydrate supplementation prior to CABG or spinal surgery, 38 patients were randomized to receive a carbohydrate supplement or to fast for 12 hours preoperatively. Baseline and postoperative measurements of insulin sensitivity were completed using the short insulin tolerance test and homeostasis model assessment (HOMA). Patient discomfort was measured immediately before surgery. Insulin sensitivity was not significantly different between groups. However, the supplemented group experienced a significantly smaller rise in glucose levels following surgery (p=0.03) and had higher postoperative HOMA-β scores (p=0.02). Fasted patients were significantly more thirsty (p=0.01), hungry (p=0.04) and anxious (p=0.01) before surgery and experienced a significantly longer hospital stay (p=0.008). Carbohydrate supplementation improved outcomes, warranting re-evaluation of fasting practices prior to major surgery.

Bakalauro darbe analizuojamas kineziterapijos vertikalioje vonioje ir salėje procedūrų derinimo poveikis, pacientų funkcinės būklės, skausmo, nugaros ir pilvo raumenų statinės ištvermės kaitai, esant juosmeninės stuburo dalies skausmams. / Physiotherapy bachelor thesis analyzes the vertical bath and hall harmonization of procedures and the patient's functional status change in lumbar spine pain.

The cervical spine must provide structural support for the head, allow large range of motion and protect both the spinal cord and branching nerves. There are two types of spinal joints: the intervertebral discs which are flexible connections and the facets, which are articulating synovial joints. Both types degenerate with age. Current surgical treatments include spinal fusion and articulating disc replacement implants. If both disc and facet joints are degenerated, fusion is the only option. In spinal fusion, the disc is removed and the adjacent vertebrae are fused which causes abnormally high stress levels in adjacent discs. In disc replacement, an articulating device is inserted to restore intervertebral motion and mimic healthy spinal kinematics. Disc arthroplasty does not significantly increase adjacent level stress but the lack of rotational constraint causes increased facet contact pressures. Thus, there is a need for a cervical total level arthroplasty system (CTLAS) that has a disc implant specifically designed to preserve the facet joints and implants for facet arthroplasty that can act independently or in-unison with the disc replacement. The conceptual design of a CTLAS implant system was proposed that would replace the disc and the facet joints. To facilitate medical imaging, PEEK (polyetheretherkeytone) was selected as the structural and bearing material. In the present thesis, multi-station pin-on-plate wear testing was initiated for pairs of unfilled (OPT) and carbon-fiber-reinforced (CFR) PEEK. Wear is important in arthroplasty implant design because wear particles can cause osteolysis leading to loosening. A variety of experiments were performed to investigate the effects of load, contact geometry and lubricant composition on wear. CFR PEEK was found to have much lower and more predictable wear than OPT PEEK in the present experiments. The wear of OPT PEEK pairs showed sensitivity to lubricant protein concentration. The coefficient of friction during testing was found to be quite high (up to 0.5), which might have clinical implications. Also, some subsurface fatigue was found, exposing carbon fibers of CFR PEEK. This remains a concern for its long-term application. Further wear testing is recommended using actual implants in a spine wear simulator.

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.