Low back pain is also a vast socioeconomic issue which costing American taxpayers more than $50 billion yearly. Estimates state that up to 75% of low back pain is caused by lumbar degenerative disc disease. The nucleus seems plays a critical role in pain related to disc degeneration; it is the starting point of the degenerative cascade. All of these factors make it the focus of novel treatment options. The goal of this study is to create idealized models to determine the shape of nuclear implant best suited to resist the standard shear and torsional stresses that are generated in the lumbar spine. Thus, five nuclear intervertebral disc prosthetics (Implant designs 1-5) were designed. Shear testing was conducted using an Instron, and torsion testing was conducted using the LabVIEW in conjunction with a torsional pneumatic cylinder. Implant design 4 was determined to be the implant design best suited to resist shear stresses. Implant design 3 was determined to be the implant design best suited to allow normal torsion of the spine. Therefore, it was determined that a combination of implant design 3 and implant design 4 might be optimal in terms of shear, torsion, wear, and stability.

Thesis (doctoral)--Lund University, 1996. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1996. / Added t.p. with thesis statement inserted.

M. Tech. / Abstract Purpose: The purpose of this study was to assess the effects of Diversified Chiropractic adjustments versus Flexion-Distraction Technique in the management and treatment of chronic Lumbar Facet Syndrome. Method: This study consisted of two groups, Group A and Group B, each consisting of 15 participants with chronic Lumbar Facet Syndrome. The participants were between the ages of 20 and 45 years. Potential candidates were examined and accepted based on the inclusion and exclusion criteria. Group A received Diversified Chiropractic Adjustments and Group B received Flexion-Distraction Technique to the lumbar facets. Procedure: Each participant was treated eight times over a period of four weeks. Before the commencement of treatment one, four and eight, the participants completed the Oswestry Low Back Pain and Disability Index questionnaire and the Visual Analogue Scale. A Digital Inclinometer was used to measure lumbar spine ranges of motion. Diversified Chiropractic adjustments were then administered to Group A based on the restrictions obtained during motion palpation. Flexion-Distraction Technique was administered to Group B based also on the restrictions that were obtained during motion palpation. Results: Objective statistically significant differences were noted on flexion and left lateral flexion ranges of motion before treatment, and clinically significant differences we noted on flexion and right lateral flexion after treatment, in favour of Group A. Subjective readings also showed statistically significant differences with regards to Oswestry Low Back Pain and Disability Index and Visual Analogue Scale in favour of both Group A and Group B. Conclusion: The results of the study indicate that both Diversified Chiropractic adjustments and Flexion-Distraction Technique have a positive effect on patients suffering from chronic Lumbar Facet Syndrome. However, Diversified Chiropractic adjustments proved to have a greater overall benefit compared to Flexion-Distraction Technique in the management and treatment of Lumbar Facet Syndrome.

M.Tech.

The aim of this project was to develop robust interactive computer methods for measuring the shape and movement of the lumbar spine vertebrae from lateral radiographs of the spine. In order to achieve this aim, two software packages were written - the Aberdeen Vertebral Morphometry System (AVMS) and the Aberdeen Spinal Videofluoroscopy System (ASVS). AVMS was designed to analyse static images from dual energy x-ray absorptiometry (DXA) imaging densitometers. Comparative precision tests of the ability of AVMS software and Lunar EXPERT-XL software to measure vertebral height were undertaken using four vertebrae from the same lateral spine image (male, 67 years). Two of the vertebrae in this image were abnormal and two were normal. It was concluded that AVMS had higher precision when measuring abnormal and normal vertebrae. The effects of axial rotation and lateral bending, which lead to movement out of the sagittal plane, were investigated by generating a three-dimensional computer model of two adjacent vertebrae and projecting it on to the sagittal plane. The projected model was measured as if it were a radiograph, allowing the effects of out-of-plane movement and errors in reference point placement to be calculated. ASVS was used to acquire and analyse a sequence of images of the spine in motion obtained using videofluoroscopy and incorporated the findings of the computer modelling work. A clinical study for the measurement of intervertebral motion using ASVS during flexion-extension was organised and seven subjects suffering from severe lower back pain were recruited. Analysis of the image sequences using the computerised measurement system in ASVS revealed the apparent effect of analgesia/sedative on the shape and size of centroidal trajectories of vertebrae, and the differences in trajectory shape between subjects. It was concluded that ASVS was able to quantify spinal motion at a minimal radiation dose to the subject.

M.Tech.

Limited hip mobility is known to affect the lumbar spine. Much of the previous research has utilized a participant population whose hip mobility is compromised due to arthritic or neurological dysfunctions. Such aetiologies may confound the outcomes, as their effects may not be limited to the hip. The purpose of this thesis was to recruit a healthy young adult population with limited hip mobility to further investigate its effect on the lumbar spine, as well as the role of exercise intervention. Several cascading studies were conducted that were unified around a central theme of links between hip and spine function: Study # 1 investigated the normal distribution of passive hip extension and rotation in a group of 77 males (age 19-30). Data was collected using an infra-red motion capture system and compared to goniometric measurements. The resulting angles represent the 5th – 95th percentiles, including the averages and standard deviations. Study # 2 compared movement patterns between groups of males with limited and excessive hip mobility. Participants were required to perform simple functional activities (lunging, twisting, walking, etc) as well as use the elliptical trainer. Resulting hip and spine angles demonstrated that the men with limited hip mobility stood with a more anteriorly tilted pelvis, and assumed a posture with more lumbar and hip flexion on the elliptical trainer, compared to those with greater mobility. This, in turn, resulted in a greater lumbar compression load due to increased back muscle activity. Study #3 involved recruitment of 24 young adult males with limited hip mobility. Their movement patterns were assessed (as in study #2), then they were assigned to one of four intervention groups: hip stretching, spine stabilizing, hip stretching combined with spine stabilization, and control. Participants in the 3 exercise groups attended supervised exercise sessions once/week for 6 weeks, but were expected to exercise a minimum of 4 times/week on their own. At the end of the 6 weeks, intake parameters were re-assessed, and movement pattern assessment repeated. Despite significant increases in available hip flexibility and/or large increases in trunk muscle endurance and trunk motor control, there were few indications that participants were any more adept at decreasing lumbar motion, or utilizing their newfound hip flexibility during functional activities. Study #4 compared those in the 10th and 90th percentiles of available hip rotation, using a frictionless apparatus to investigate passive stiffness properties of the hip. Participants adopted a posture of upright standing, with one leg supported on a turntable apparatus, and upper body and pelvis secured. A an applied rotational moment resulted in passive hip internal and external rotation. Outcomes demonstrate that those with limited hip mobility stand with the leg more externally rotated and require a larger moment to initiate motion. Passive stiffness curves indicate greater stiffness properties in those with limited hip mobility, and more resistance to an external rotation moment than internal rotation. Study #5 investigated passive hip stiffness in the sagittal plane, comparing those with limited and excessive hip extension. Using a frictionless jig, with the participants lying on their left side, the left hip was pulled into extension with knee position varying. Those with limited hip mobility demonstrated increased passive stiffness compared to the more mobile group, and stiffness was greater when the knee was in extension. The group with limited mobility also showed a trend of increased back extension compared to the more mobile group, when the hip and lumbar spine were both free to react to the applied extension moment. Study #6 summarizes the spine/hip kinematics and muscle activation levels produced when using the elliptical trainer, as well as lumbar compressive and shear forces. It differs significantly from walking in that it produces more lumbar motion in flexion/extension and lumbar twist, but less lateral bend. Participants also tended to adopt a greater mean lumbar flexion angle on the elliptical, which in turn resulted in greater muscle activity in the back extensors. Varying hand position, velocity and stride length were all found to significantly affect the amount of lumbar motion. Highly phasic muscle activity is seen, with the gluteal muscles and internal obliques demonstrating the greatest activation levels.

Thesis--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references (p.108-111, etc.).

Intervertebral disc(IVD) degeneration is associated with low back pain (LBP).Despite the endplates are located adjacent to the IVD, the phenotypes of endplate and vertebral bone marrow changes remain unclear. The objective of this study is to assess the prevalence and the associated determinants of these phenotypes of the lumbar spine. 2449 Southern Chinese subjects (aged 10 –88 years) undergone sagittal T2-weighted magnetic resonance imaging (MRI)examination to assess the presence of endplate and vertebral bone marrow changes including Schmorl’s nodes (SN) and Modic changes (MC),respectively, and scored for additional radiographic features over the lumbar spine. Subjects’ demographics, clinical profile, and functional status were assessed by means of standardized questionnaires. Anovel6-domain SN morphological classification based on MRI was developed to further analyze the characteristics of SN and its association with disc degeneration (DD). The prevalence of SN was 16.4%. Males, taller and heavier individuals had a significantly increased likelihood of SN. Overall presence of SN was age-independent, but was significantly associated with DD, and linearly correlated with increase in severity of DD. SN were particularly associated with severe DD at the upper two lumbar levels (L1/2 – L2/3). Based on the SN classification system, specific SN characteristics and endplate linkage patterns were found. Of these, two SN types were identified:“Typical SN” and “Atypical SN”. “Typical SN” were those smaller size SN with various shapes that were frequently located at caudal endplates of L1/2–L3/4disc levels. One variant of “Atypical SN” were those rectangular shape SN, which predominantly located at the posterior region of the rostral endplates of L1/2–L2/3disc levels. The other variant of “Atypical SN” was larger size SN with irregular shape that frequently presented at the L4/5endplates, they were also likely to be associated with marrow changes. Despite “Atypical SN” only entailed 8.3% of all identified SN, they were associated with increased severity of DD than “Typical SN”. Although the overall prevalence of MC among Southern Chinese was low (5.8%), after adjustments for other confounding factors, the presence of MC was associated with the presence and severity of LBP. Interestingly, the determinants of MC at upper (L1/2 – L3/4) and lower (L4/5 – L5/S1) lumbar showed distinct difference. The presence of MC at upper lumbar levels was only associated with the disc integrity only (i.e. the presence of disc displacement, and DD score), while the presence of MC at the lower levels, apart from the disc integrity, was also associated with increasing age, the presence of SN, smoking and obesity status. This study is the largest MRI study assessing the phenotypes of endplate and vertebral bone marrow changes in-vivo. The prevalence and distribution of SN and MC vary throughout the lumbar spine, and there are level and region-specific variations regarding these phenotypes. Determinants of SN and MC may be similar but do vary, suggesting distinct etiological factors. Findings of this study broaden the understanding of the various phenotypes of the lumbar spine and its association with DD. / published_or_final_version / Orthopaedics and Traumatology / Doctoral / Doctor of Philosophy