Dissertation submitted in partial compliance with the requirements for the Master's Degree in Technology: Chiropractic, Technikon Natal, 1999. / Objectives To investigate the efficacy of spinal manipulative therapy (SMT) in the management of mechanical thoracic spine pain. It was postulated by the researcher that with manipulation of the affected thoracic spinal segment, there would be a significantly greater improvement than by only applying placebo treatment. Summary of background data There have been no substantiated studies performed up to this date to investigate the efficacy of SMT on thoracic syndromes. Study design A single-blind, randomised, comparative, controlled pilot study. Methods Thirty subjects selected from the general population, diagnosed as having mechanical thoracic spine pain, were randomly divided into two different treatment groups. Each group consisted of fifteen patients between the ages of 16 and 60 years. The first group received thoracic spine manipulation. The second group received placebo treatment only. iii The research project was carried out where both groups received a maximum of six treatments over a minimum period of two weeks. Thereafter a follow-up appointment / M

Dissertation submitted in partial compliance with the requirements for the Master's Degree in Technology: Chiropractic, Technikon Natal, 2001. / The purpose of this study was to evaluate thoracic spine manipulation in comparison to interferential current therapy in order to determine the relative effectiveness of each treatment protocol in the management of mechanical thoracic back pain. The design was that of a single blind, randomized, comparative pilot study. Sixty patients were selected from the general population, of which 30 patients made up group one and the other 30 patients made up group two. After an extensive case history and physical examination the patients were diagnosed with mechanical thoracic spinal pain and then randomly divided into the two groups. The first group received spinal manipulative therapy and the second group received interferential current therapy. All sixty patients received a minimum of three or up to a maximum of six treatments. The treatments were given two to three times a week. Objective and subjective data was collected before the first, second and final treatment in order to assess the effectiveness of each treatment protocol. The objective data consisted of thoracic range of motion using the BROM II goniometer and pain threshold using an algometer. The subjective data was collected using the Short-form Pain Questionnaire, Numerical Pain Rating Scale -101 and the Oswestry Back Pain Disability Index Questionnaire. The data gathered at the relevant appointments was then statistically analyzed, using a 95% (a = 0.05) confidence level. Inter-group analysis was performed using the Unpaired T- test and the Mann- Whitney U - test for the continuous and categorical variables respectively. The Oswestry Back Pain Disability Index Questionnaire showed a statistical difference at the final visit when compared between the two groups. / M

Nucleus replacement has recently come into favor as a possible treatment for Degenerative Disc Disease. Replacing degenerative nucleus tissue with a synthetic material that mimics healthy nucleus tissue may restore normal function and biomechanics to the disc and delay or obviate the need for more invasive procedures such as total disc replacement and fusion. This thesis evaluated a novel protein polymer hydrogel composed of silk and elastin as a nucleus replacement material. There are three experimental components; one in vivo and two in vitro portions. In the first experimental portion, a large animal model was developed to evaluate the biocompatibility of the material as well as the effect on surrounding boney and soft tissues. Three discs were evaluated in each animal; sham, discectomy and discectomy treated with hydrogel. Discs were evaluated at 4, 26 and 52 weeks. The hydrogel group showed a quiet cellular response, as well as decreased boney remodeling and fewer degenerative changes when compared to the discectomy group. The second experimental portion evaluated the biomechanics of 9 cadaveric motion segments loaded in axial rotation, lateral bending, flexion/extension (FE) and compression. Specimens were tested sequentially in the intact state, following annulotomy, discectomy and after hydrogel treatment. Range of Motion (ROM) in FE was shown to increase from the intact state (8.50+/-1.44˚) to the discectomy state (9.86+/-1.77˚) and decrease following hydrogel treatment (8.66+/-0.76˚) to be similar to the intact ROM. The third experimental portion investigates the effect of three commonly applied testing conditions on the mechanical properties of spinal segments. 27 motion segments were tested at 18˚C wrapped with Phosphate Buffered Saline (PBS), at 37˚C in a PBS bath, and at 37˚C and 100% humidity. Specimens were tested hourly for 6 hours. The heated conditions were shown to have lower stiffness and increased range of motion when compared 18 ˚C tests. Repeated testing with time increased neutral zone and ROM for all modes of bending. As tests are repeated over time, tissue properties change and may mask the ability of a nucleus replacement to restore biomechanics.

Discitis is a potential complication of any open or percutaneous spinal procedure which involves entry into the intervertebral disc. The infection initiates an inflammatory response which leads to endplate rupture. Although there are variations in the severity of symptoms, the main feature of discitis is severe back pain which is not relieved by rest. The infection may spontaneously resolve over time although incapacitating back pain may persist for many months. In some cases serious complications result from the spread of infection to the adjacent vertebral bodies and over time osteomyelitis will develop with resultant bone destruction and collapse. The prognosis for many patients with discitis is poor with continual disabling back pain, prolonged absence from gainful employment and inability to return to daily living activities. Clinical and experimental evidence now supports the prophylactic use of a suitable antibiotic to prevent discitis. In South Australia cephazolin is the antibiotic of choice to prevent or treat discitis due to Staphylococcus spp. While cephazolin has been shown to prevent discitis after inoculation with Staphylococcus spp. it is not universally accepted. Uncertainty exists regarding the ability of the antibiotic to enter the disc, and if it is effective in preventing and treating discitis. This is further complicated by the lack of suitable methods for detecting and measuring the concentration of cephazolin in the disc. An experimental ovine model was used to investigate ( a ) the natural progression of discitis in the growing lumbar spine ; ( b ) a technique to detect and measure the concentration of cephazolin in the disc ; ( c ) the effect of prophylaxis when dose and time of administration of cephazolin was varied ; ( d ) the effect of parenteral cephazolin after discitis was established and ( e ) the influence of health and age of the disc on prophylactic and parenteral treatment with cephazolin. In a clinical study the concentration of cephazolin was measured in degenerate human disc tissue to determine if therapeutic concentrations were achieved. The ovine studies showed that discitis had no significant effect on the development of the growing lumbar spine after one year although infection was associated with reduced disc area and height. Preventing discitis with cephazolin was reasonably successful, regardless of age and health of the disc. Timing of cephazolin administration was crucial to prevent discitis in immature animals. A high - performance liquid chromatography technique was used to measure the concentration of cephazolin in the disc. The greatest concentration of cephazolin in ovine discs was achieved 15 minutes after a bolus dose of intravenous antibiotic was administered, although detectable levels were measured for a further 2 hours. The concentration of cephazolin was not uniform across the disc with greater concentrations in the outer disc compared to the inner disc. Although there were measurable levels of cephazolin in these discs, it was ineffective at treating discitis once established. In the clinical study detectable levels of cephazolin were recovered in human discs for more than 2 hours after administering a 1 - g bolus dose. The concentration of cephazolin peaked in the human discs between 37 and 53 minutes, but in only half of the discs was the concentration of cephazolin considered therapeutic against Staphylococcus aureus. While discitis may spontaneously resolve over time, the infected disc does not recover to its original form. Furthermore, parenteral cephazolin was ineffective at preventing endplate destruction once an intradiscal inoculum was established. While this study proved cephazolin is able to enter the disc and provide reasonable protection against infection, it appears that discitis cannot be completely abolished. The timing of prophylaxis remains a critical factor to achieve therapeutic concentrations of cephazolin in the disc. Due to the serious complications that result from discitis this study supports the use of prophylactic antibiotic administered at an optimal time before the disc is violated during any spinal procedure. / Thesis (Ph.D.)--School of Medical Sciences, 2006.

Lumbar spine fusion (LSF) is a common surgical procedure used in the treatment of lower back pain. Numerous studies have been conducted investigating the effects of LSF. Biomechanical studies have found that mechanical changes at adjacent joints create cumulative stress and pain, while clinical studies suggest that many patients develop symptomatic adjacent segmental disease (ASD) following LSF, which may necessitate additional surgery. Recently, ASD pain following LSF has been attributed to accelerated sacroiliac (SI) joint degeneration. Normal SI joints are mobile segments adjacent to the lumbosacral spine articulation and it has been hypothesized that altered biomechanics at the SI joints due to LSF could accelerate degeneration of the joints. The purpose of this study was to obtain a better understanding of the biomechanics at the SI joints and to determine whether LSF causes biomechanical changes at the SI joints. Six cadaver pelves were tested in flexion/extension, torsion, double leg compression and single leg compression, under four conditions: 1) intact, 2) after a 360 degree instrumented fusion at L4-5, 3) after a 360 degree instrumented lumbosacral fusion at L4-S1 and 4) after a unilateral SI joint fusion. Anterior and posterior SI joint movements were recorded during the study, along with load/displacement data. This study proved that motion does exist at the SI joints, although it is quite variable between specimens and between right and left SI joints within an individual specimen. It was also determined that changes in biomechanics do occur at the SI joints following fusion (L4-5, L4-S1 and unilateral SI joint fusion). Anteriorly, an overall increase in motion was detected at the SI joints during axial compression as fusions were performed. The posterior SI joints also demonstrated increased motion, however, this increase was detected in all of the parameters tested (flexion/extension, torsion and axial compression). However, due to the small number and variability of specimens tested, significance could not be established. The results of this study may help surgeons make more informed decisions, by being made aware of SI joint degeneration as a possible side effect of fusion surgeries, and taking that into consideration when determining a treatment plan.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Introduction: Lumbar spine stability programs have been advocated to prevent and rehabilitate low back injury. Specifically, abdominal ‘drawing in’ has been used to train motor control deficits in individuals with low back pain. This technique requires differential activity within deep and superficial lumbar multifidus fibres, yet the ability of these fibres to act differentially has not been extensively examined. Deep fibres are hypothesized to act as spinal stabilizers while superficial fibres are hypothesized to act as global movers of the trunk. Objective: To investigate differential excitation of deep and superficial lumbar multifidus fibres during segmental indentation loads to the lumbar spine. Methods: Posterior-anterior indentation loads were applied to individual lumbar spinous processes of prone participants at three different velocities and three different indentation displacements. Indentations consisted of an initial downward displacement that was subsequently held for 500 milliseconds. Intramuscular electromyography (EMG) of deep and superficial lumbar multifidus fibres at L3, L4 and L5 was recorded. EMG was quantified by “average” root mean square (RMS), peak RMS of a sliding RMS window and time-to-peak RMS over the indentation phase and 500 millisecond hold phase. Results: Increased indentation displacement at the slowest velocity resulted in increased “average” RMS of only the L5 superficial multifidus fibres. Increased indentation velocity produced differential effects in deep and superficial multifidus fibres. “Average” RMS and peak RIVIS significantly increased with increasing indentation velocity in most deep fibre recording sites, yet superficial fibre excitation did not significantly increase. In most EMG recording sites, the time-to-peak RMS increased with increasing indentation displacement and decreased with increasing indentation velocity. Conclusion: Differential excitation of superficial and deep multifidus fibres was found with increasing indentation velocity; however, the result was opposite to that hypothesized. This result is clinically relevant because it suggests deep multifidus fibre excitation may increase in response to increased perturbation magnitude, possibly to restore vertebral body position. Differential excitation effects may also be related to different mechanical stimuli experienced by deep and superficial fibres due to vertebral body movement during indentation loads. 11

Research has uncovered an essential role of proper abdominal muscle function in ensuring the health and integrity of the lumbar spine. The anatomical arrangement of the abdominal musculature (rectus abdominis, external oblique, internal oblique, transverse abdominis) and intervening connective tissues is unique in the human body. Despite the hypothesized importance and uniqueness of the abdominal muscles, very little research has been directed to understanding their role from a neuro-mechanical standpoint. Thus, this thesis was designed to study the neuro-activation and mechanical characteristics of the abdominal musculature and connective tissues, with a specific focus on torso stiffening mechanisms. Several experiments were performed and unified around this theme. The first study explored the fundamental relationship between EMG muscle activation recordings and the moments generated by the trunk musculature. This study was novel in that investigation of the abdominal musculature was augmented with consideration of antagonist muscle co-activation. The main finding was that the EMG-moment relationships were quite similar in both the abdominal and extensor muscle groups; however, the form of this relationship differed from that often reported in the literature. Specifically, consideration of antagonist muscle moments linearized the EMG-moment relationship of the agonist muscle groups. Once this activation-moment relationship had been established, the next line of questioning explored the association between torso muscle activation, driven through the abdominals, and torso stiffness. Two studies addressed this issue: the first examined the intrinsic resistance of the torso to bending in the flexion, extension, and lateral bend directions, while varying the levels of torso muscle activation; the second examined the response of the trunk to perturbations while varying the levels of torso muscle activation under the presence of limited reflexes. The first of these two studies demonstrated a rise in trunk stiffness as muscle activation increased over the lower 40% of range of motion. At greater ranges of motion in flexion and lateral bend the trunk appeared to become less stiff as the musculature contracted to higher levels. The latter study revealed substantial spinal displacements in response to trunk perturbations, indicating that in the absence of reflex activity, the stiffness produced by muscular contraction may be inadequate to stiffen the torso to prevent damage to spinal tissues. The fourth study was designed to enable in-vivo observation of abdominal muscle and connective tissue deformation using ultrasound imaging. During relatively simple abdominal contractions, the oblique aponeurosis demonstrated surprising deformation patterns that often exhibited the characteristic of a negative Poisson’s ratio. This was hypothesized to be facilitated by the composite laminate arrangement of the abdominal wall, whereby the loose connective tissues separating layers of collagen fibres may allow for separation of adjacent layers, giving the appearance of structural volume expansion. Further, a lateral displacement of the rectus abdominis muscle was noted in a majority of contractions, highlighting the dominance of the laterally oriented forces generated by the oblique muscles. The final study questioned, at a basic level, the nature of the anatomical arrangement of the abdominal muscle-connective tissue network. Examining the contraction of the rat abdominal wall uncovered the transfer of muscularly generated force and stiffness through the connective tissues binding the layered muscles. This suggests a functionality of the abdominal wall as a composite laminate structure, allowing substantial multi-directional stiffness to be generated and transmitted around the torso, thereby enhancing the ability to effectively stabilize the spine.

Research has uncovered an essential role of proper abdominal muscle function in ensuring the health and integrity of the lumbar spine. The anatomical arrangement of the abdominal musculature (rectus abdominis, external oblique, internal oblique, transverse abdominis) and intervening connective tissues is unique in the human body. Despite the hypothesized importance and uniqueness of the abdominal muscles, very little research has been directed to understanding their role from a neuro-mechanical standpoint. Thus, this thesis was designed to study the neuro-activation and mechanical characteristics of the abdominal musculature and connective tissues, with a specific focus on torso stiffening mechanisms. Several experiments were performed and unified around this theme. The first study explored the fundamental relationship between EMG muscle activation recordings and the moments generated by the trunk musculature. This study was novel in that investigation of the abdominal musculature was augmented with consideration of antagonist muscle co-activation. The main finding was that the EMG-moment relationships were quite similar in both the abdominal and extensor muscle groups; however, the form of this relationship differed from that often reported in the literature. Specifically, consideration of antagonist muscle moments linearized the EMG-moment relationship of the agonist muscle groups. Once this activation-moment relationship had been established, the next line of questioning explored the association between torso muscle activation, driven through the abdominals, and torso stiffness. Two studies addressed this issue: the first examined the intrinsic resistance of the torso to bending in the flexion, extension, and lateral bend directions, while varying the levels of torso muscle activation; the second examined the response of the trunk to perturbations while varying the levels of torso muscle activation under the presence of limited reflexes. The first of these two studies demonstrated a rise in trunk stiffness as muscle activation increased over the lower 40% of range of motion. At greater ranges of motion in flexion and lateral bend the trunk appeared to become less stiff as the musculature contracted to higher levels. The latter study revealed substantial spinal displacements in response to trunk perturbations, indicating that in the absence of reflex activity, the stiffness produced by muscular contraction may be inadequate to stiffen the torso to prevent damage to spinal tissues. The fourth study was designed to enable in-vivo observation of abdominal muscle and connective tissue deformation using ultrasound imaging. During relatively simple abdominal contractions, the oblique aponeurosis demonstrated surprising deformation patterns that often exhibited the characteristic of a negative Poisson’s ratio. This was hypothesized to be facilitated by the composite laminate arrangement of the abdominal wall, whereby the loose connective tissues separating layers of collagen fibres may allow for separation of adjacent layers, giving the appearance of structural volume expansion. Further, a lateral displacement of the rectus abdominis muscle was noted in a majority of contractions, highlighting the dominance of the laterally oriented forces generated by the oblique muscles. The final study questioned, at a basic level, the nature of the anatomical arrangement of the abdominal muscle-connective tissue network. Examining the contraction of the rat abdominal wall uncovered the transfer of muscularly generated force and stiffness through the connective tissues binding the layered muscles. This suggests a functionality of the abdominal wall as a composite laminate structure, allowing substantial multi-directional stiffness to be generated and transmitted around the torso, thereby enhancing the ability to effectively stabilize the spine.

Approximately 50% - 80% of the population will experience disabling low back pain at some point in their life. Assessing and developing interventions based on “lumbar stability” and/or joint stiffness to reduce low back pain has been a common research focus. Specific focus has been on identifying which muscles influence lumbar stability/stiffness, with one argument being between focusing training on the transverse abdominis and lumbar multifidus muscles versus broader training approaches involving the entire abdominal wall and erector spinae muscles. However, there has not been research on whether pain reduction was due to increased stability/stiffness or another mechanism. The main goals of this thesis were to determine the effect of individual muscles on stability/stiffness through a two phase process. In the first phase, a model sensitivity analysis was performed to assess the interactions of variables that influence the quantification of stability. Stability was quantified via the eigenvalues (EV) of the Hessian matrix of potential energies at each lumbar level and axis of rotation, for a total of 15 EVs (3 axes of rotation x 5 joints). In phase 2, assessment of clinical interventions on patients with low back pain designed to alter biomechanics was conducted to assess factors in stability/stiffness quantification and mechanisms of action in pain modulation. More detail of the study phases are described below, in order to test the following hypotheses: 1) It was hypothesized that individual muscles affect specific EVs, but no one muscle can be associated with one EV level. 2) It was hypothesized that specific muscles do affect specific planes of stability/stiffness. 3) It was hypothesized that EVs are affected by posture. 4) It was hypothesized that overactivating muscles by increasing muscle activation to 100% MVC negatively affects the EVs. 5) It was hypothesized that the relationship between muscles and specific EVs obtained during simulation remains with real subjects performing loaded tasks. 6) It was hypothesized that coaching and cueing specific movement patterns and motor patterns would alter pain in low back pain patients. 7) If hypothesis 6 is true, then it was hypothesized that changes in pain would be reflected in changes in EVs. Methods for Phase 1 The first phase involved a sensitivity analysis using an anatomically detailed spine model. Theoretical data including posture, motion and muscle activity were synthesized to include 23 static spine postures, including neutral, 0° - 50° flexion, 0° - 30° extension, 0° - 30° right and left lateral bend, and 0° - 40° right and left axial twist, all in increments of 10°. For each posture, all eleven muscles included in the model, some with several fascicles, were artificially activated to 50% MVC. A knockout approach ensued whereby activity in single muscles were systematically reduced to 0% MVC or increased to 100% MVC. The relationships between the 15 EVs and the changes in muscle activity and posture were assessed. This muscle knockout model was repeated with actual muscle activity values obtained from electromyographic (EMG) signals and postures obtained from four subjects who performed a walking task with a 15 kg load in each hand. Results for Phase 1 The sensitivity analysis showed that the abdominal muscles contribute a greater stabilizing effect on the L4 and L5 EVs, while the multifidus and erector spinae muscles contribute a greater effect on the L1, L2 and L3 EVs. When examining the effect of muscles on a specific plane in terms of influencing stability/stiffness, it was found that the abdominal muscles contribute a greater effect on the bend axis and twist axis EVs than the flexion axis EVs, while the erector spinae muscles contribute the greatest effect on the flexion axis EVs. Posture was found to have a biologically significant effect on EVs, with the 50° flexion and 30° extension postures having the most detrimental effect in terms of compromising stability/stiffness. In addition, when there was a 10° excursion in any axis, there was little change in the EVs, while postures at angles greater than this were often associated with decreases in stability/stiffness in some EVs. Increasing the muscle activation from 50% MVC to 100% MVC did not have a large effect on most EVs, but when there was a meaningful change, as defined by a change of 10% or greater in the EV, the 100% MVC activation level always resulted in more stability/stiffness at that particular EV. Finally, using actual EMG and lumbar angle patterns resulted in similar results as the theoretical data, as expected. Interpretation of these findings is limited by the following. Even though EVs changed, there is no guarantee that the magnitude of change in one EV could be interpreted to equal a similar magnitude of change in another EV, nor may it be assumed that EVs have a linear relationship with stability/stiffness. These results suggest that when the goal is to increase lumbar stability, a neutral spine should be maintained and activating the larger abdominal muscles is more important than activating the transverse abdominis or multifidus, as proposed by some clinical groups. Methods for Phase 2 Four case studies of individuals with chronic low back pain were recruited from whom kinematic, kinetic and EMG data were collected in addition to a measure of pain intensity using an 11-point verbal numerical rating scale. Pain provocation tests were performed by a clinician (professor Stuart McGill) to identify the motions, postures and loads that exacerbated their pain. Then these tasks were repeated while the motion and EMG data was collected. This was followed by interventions coached by the clinician that could include the abdominal brace (stiffening the abdominal wall), latissimus dorsi stiffening, incorporating a hip-hinge motion rather than spine bending, or any combination of these. The intention of the intervention was to immediately reduce pain intensity. These tasks arranged in a repeated measures design were assessed with the anatomically detailed spine model to calculate stability/stiffness from evaluation of the 15 EVs, lumbar compression and lumbar shear forces. Results for Phase 2 The results from phase 2 suggest that pain was sometimes reduced by altering motions, postures and load, but the mechanism of what proved effective and the degree of success was variable from patient to patient. In most situations, the EVs, lumbar compression forces and lumbar shear forces increased due to the intervention that was chosen. In addition, the lumbar flexion angle typically trended to a more neutral posture and in tasks where spine motion occurred, there was less spine motion when using the suggested intervention. Further, the biomechanical variable that would be expected to change based on clinical assessment did not always react in the expected way (i.e. a compression intolerant individual would be expected to have decreased compression linked with decreased pain, but this did not occur). While the stability/stiffness increased, the associated compression was tolerated suggesting that the increase in concomitant stiffness enhanced the compression load bearing tolerance. Overall Conclusions This thesis showed that careful examination of the EVs did not offer substantial insight into links between changes in individual EVs and individual muscles, as muscle activity was not reflected in the EVs. Specifically, single muscles contributions were not reflected in specific EVs as was hypothesized. Further, it was difficult to interpret the EVs collectively because of the inherent non-linearity between EV magnitude and changes in muscle activation/stiffness; it can only be said that there was more or less stability/stiffness with each change in an EV, not how much. In addition, pain reduction appeared to be due to a combination of altered motions, postures and loads, but this did not result in systematic EV changes. Globally, the present work provides evidence supporting the idea that maintaining a neutral posture and activating the abdominal muscles results in less pain and larger EVs, suggesting an increase in stability/stiffness. This work has potential for informing clinicians on possible options for immediate reduction in low back pain.