Introducción: Diversos factores estresantes generan dolor lumbar en conductores. La inadecuada forma de sentarse, el tiempo prolongado en dicha postura, la congestión vehicular, largas horas de trabajo, descansos reducidos y un peso elevado, se han asociado a la presencia de dolor y trastornos musculo esqueléticos. A nivel más específico, como en el caso de las dimensiones del asiento, aún falta evidencia. Objetivo: Determinar si existe asociación entre las dimensiones del asiento y el dolor lumbar en choferes. Métodos: Se realizó un estudio observacional de tipo transversal analítico en la empresa de transportes ETS. Múltiples J. SA de la ciudad de Barranca, la población estuvo conformada por choferes de sexo masculino a los que se les evaluó mediante el “Report of the national institutes of health task force on research standards for chronic low back pain” la adecuación al asiento con los parámetros de Parcells y las medidas antropométricas fueron consideradas según el método ISAK. Resultados: Se realizó la encuesta y las medidas antropométricas a 85 choferes donde aproximadamente 66% presenta dolor lumbar, 32% de los choferes utiliza un accesorio para el asiento que le genere mayor comodidad y el 66% de los choferes consume algún tipo de analgésico. También se muestra una correspondencia de la diferencia de las medidas antropométricas y las dimensiones del asiento, en donde la altura del asiento adecuado y el ancho del respaldar inadecuado presentan asociación estadísticamente significativa. Conclusiones: Se encontró como resultado que las dimensiones altura del asiento y ancho del respaldar están asociados al dolor lumbar en choferes. / Several stressors generate musculoskeletal disorders in drivers. Inadequate sitting, prolonged time in this posture, traffic congestion, long working hours, reduced rest periods, and high weight have been associated with the presence of pain and musculoskeletal disorders. Objectives: To determine if there is an association between seat dimensions and back pain in drivers. Methods: An observational cross-sectional analytical study was carried out in transport company ETS. Múltiples J. SA from the city of Barranca, the population was made up of male drivers. They were evaluated using the Report of the national institutes of health task force on research standards for chronic low back pain, the adequacy to the seat with the Parcells parameters and the anthropometric measurements were considered according to the ISAK method. Results: The survey and anthropometric measurements were carried out on 85 drivers, where approximately 66% of the participants presented low back pain, 32% of the drivers use a seat accessory that generates greater comfort; likewise, 66% of drivers consume some type of painkiller. A correspondence between the difference in anthropometric measurements and the seat dimensions is also shown, where the appropriate seat height and the inadequate back width present a statistically significant association. Conclusions: As a result, it was found that the dimensions of adequate seat height and inadequate backrest width are associated with low back pain in drivers. / Tesis

Introducción: Se define al dolor lumbar como un dolor en la zona de la espalda baja, entre el borde inferior de la última costilla y los pliegues glúteos. Puede presentarse en un 20 % de la población de manera intensa. La prevalencia de dolor lumbar crónico en los universitarios oscila entre 12.4 % - 75 %. Se encontró que la alteración de la musculatura del recto abdominal se encuentra relacionado con las personas que presentan dolor lumbar, a diferencia de otros músculos del Coré. Objetivo: Determinar si existe asociación entre la distancia entre los bordes mediales del músculo recto abdominal y la presencia de dolor lumbar en estudiantes de una universidad privada de la ciudad de Lima. Método: Estudio de casos y controles, realizado en estudiantes de una universidad privada de la ciudad de Lima. Nuestras variables fueron, el dolor lumbar y la distancia entre los rectos abdominales Los instrumentos fueron, ficha de datos, escala numérica de dolor (ENA), índice cintura cadera, cuestionario nórdico, escala de Oswestry y caliper digital calibrado. Resultados: Se observo que la media y desviación estándar de la distancia de los rectos abdominales (IRD) fue (21.9 ± 3.5). El dolor lumbar tuvo asociación con la variable IRD (p = 0.001); IRD cuartiles (p= 0.015) y IRD dicotomizada (p=0.004). Incluso, la variable diástasis abdominal se encontró asociada con el dolor lumbar (p=0.006). Conclusiones: Se encontró una asociación entre el (IRD) y el dolor lumbar en los estudiantes universitarios. Además, se evidencio asociación entre diástasis y el dolor lumbar. / Background: Low back pain (LBP) is defined as the pain located in the low back between the lower edge of the last rib and the gluteal folds. It can be found in 20 % of the population as intense pain. The prevalence of chronic low back pain in university students oscillates between 12.4 %-75 %. Unlike other Core muscles, the alteration of the rectus abdominis muscles is related to low back pain. Objective: To determine the association between the abdominal rectus medial edges distance and the presence of low back pain in students of a private university in Lima. Material and methods: Case-control study in students of a private university in Lima. The variables were low back pain and the inter-rectus distance. The research instruments were data collection sheet, numeric pain scale, waist-hip ratio, Nordic questionnaire, Oswestry disability index and calibrated digital caliper. Results: The mean and the standard deviation of the inter-rectus distance was 21.9 (±3.5). The variable low back pain had association with the variables inter-rectus distance (p=0.001), inter-rectus distance quartiles (p=0.015) and dichotomized inter-rectus distance (p=0.004). Additionally, the variable diastasis recti abdominis muscle was associated with low back pain (p=0.006). Conclusions: There is association between inter-rectus distance and low back pain in university students. Furthermore, an association between diastasis recti abdominis muscle and low back pain was evidenced. / Tesis

Posterior lumbar spinal dynamic stabilisation devices are intended to relieve the pain of spinal segments while prolonging the lifespan of adjacent intervertebral discs. This study focuses on the design of such a device, one that has the correct stiffness to stabilise the spinal segment by the correct amount. An initial literature survey covers contemporary topics related to the lumbar spine. Included topics are lumbar anatomy and kinematics, pathology of degenerative disc disease and treatment thereof, other spinal disorders such as spondylolisthesis and spinal stenosis, as well as the complications associated with lumbar dynamic stabilisation. The influence of factors such as fatigue and wear, as well as the properties of appropriate biomaterials are considered when determining the basis of the device design and development. Stabilising the spinal segment begins with correct material selection and design. Various designs and biomaterials are evaluated for their stiffness values and other user requirements. The simplest design, a U-shaped spring composed of carbon fibre-reinforced poly-ether-ether-ketone (CFR-PEEK) and anchored by polyaxial titanium pedicle screws, satisfies the most critical user requirements. Acceptable stiffness is achieved, fatigue life of the material is excellent and the device is very imaging-friendly. Due to financial constraints, however, a simpler concept that is cheaper and easier to rapid prototype was chosen. This concept involves a construct primarily manufactured from the titanium alloy Ti6Al4V extra-low interstitial (ELI) and cobalt-chrome-molybdenum (CCM) alloys. The first rapid prototype was manufactured using an additive manufacturing process (3D-printing). The development of the device was performed in three main stages: design, verification and validation. The main goal of the design was to achieve an acceptable stiffness to limit the spinal segmental range of motion (ROM) by a determined amount. The device stiffness was verified through simple calculations. The first prototype’s stiffness was validated in force-displacement tests. Further validation, beyond the scope of this study, will include fatigue tests to validate the fatigue life of the production-ready device. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Posterior lumbar spinal dynamic stabilisation devices are intended to relieve the pain of spinal segments while prolonging the lifespan of adjacent intervertebral discs. This study focuses on the design of such a device, one that has the correct stiffness to stabilise the spinal segment by the correct amount. An initial literature survey covers contemporary topics related to the lumbar spine. Included topics are lumbar anatomy and kinematics, pathology of degenerative disc disease and treatment thereof, other spinal disorders such as spondylolisthesis and spinal stenosis, as well as the complications associated with lumbar dynamic stabilisation. The influence of factors such as fatigue and wear, as well as the properties of appropriate biomaterials are considered when determining the basis of the device design and development. Stabilising the spinal segment begins with correct material selection and design. Various designs and biomaterials are evaluated for their stiffness values and other user requirements. The simplest design, a U-shaped spring composed of carbon fibre-reinforced poly-ether-ether-ketone (CFR-PEEK) and anchored by polyaxial titanium pedicle screws, satisfies the most critical user requirements. Acceptable stiffness is achieved, fatigue life of the material is excellent and the device is very imaging-friendly. Due to financial constraints, however, a simpler concept that is cheaper and easier to rapid prototype was chosen. This concept involves a construct primarily manufactured from the titanium alloy Ti6Al4V extra-low interstitial (ELI) and cobalt-chrome-molybdenum (CCM) alloys. The first rapid prototype was manufactured using an additive manufacturing process (3D-printing). The development of the device was performed in three main stages: design, verification and validation. The main goal of the design was to achieve an acceptable stiffness to limit the spinal segmental range of motion (ROM) by a determined amount. The device stiffness was verified through simple calculations. The first prototype’s stiffness was validated in force-displacement tests. Further validation, beyond the scope of this study, will include fatigue tests to validate the fatigue life of the production-ready device. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Dissertation in partial compliance with requirements for the Masters Degree in Technology: Chiropractic, Durban University of Technology, 2010. / The aim of this study was establish if Leander versus Static traction was useful for the treatment of facet syndrome, a common type of mechanical lower back pain seen by chiropractors. Two groups of fifteen participants were chosen on the basis of the inclusion and exclusion criteria. The first objective was to determine if Static linear traction was effective for the treatment of lumbar facet syndrome in terms of subjective and objective findings. The second objective was to determine if Leander traction was effective for the treatment of lumbar facet syndrome in terms of subjective and objective clinical findings. Lastly the third objective was to compare the subjective and objective clinical findings for both groups. Design: A randomised, two group parallel controlled clinical trial was carried out between the two sample groups. Participants had to have had chronic lower back pain (> 3months). Thirty symptomatic volunteer participants between 25 and 55 were randomly divided into two equal groups – group A (Leander traction) received 5 treatments over a 2 week period. Similarly, group B (Static linear traction) also received 5 treatments over a 2 week period. Algometer readings, Numerical Pain Rating Scale (NRS101), Pain Severity Scale (PSS) and Oswestery Disabilty Index (ODI) were used as v assessment tools. Subjective and objective clinical findings were taken on the first and second visits (i.e. 48 hours) prior to treatment and immediately after treatment. Another set of subjective and objective readings were taken one week after the fifth treatment in order to gauge the long term effects of both treatments. No treatment was given on the sixth visit. Pressure tolerance measurements using an algometer were taken at the end ranges of motion in Kemp’s test and spinal extension. Outcome measures: SPSS version 15 (SPSS Inc., Chicago, Illinois, USA) was used for statistical analysis of data. A p value of <0.05 was considered as statistically significant. The two groups were compared at baseline in terms of demographics variables and location using Pearson’s chi square tests and ttests as appropriate. Intra-group comparisons were made between all time points. A significant time effect indicated successful treatment intervention. Inter-group comparisons were achieved using repeated measures ANOVA tests for each outcome measured separately. A significant time group interaction effect indicated a significant treatment effect. Profile plots were used to assess the trend and direction of the treatment effect. Results: The results of the study showed that Leander traction and Static linear traction were both effective for treating chronic lumbar facet syndrome and no statistically significant difference was found between subjective and objective clinical findings between the two groups.

This thesis describes the development of artificial disc technology for the replacement of intervertebral discs in the human lumbar spine. The clinical problem is back pain. There may be a relationship between certain forms of back pain and disc degeneration. The mechanical properties of human intervertebral discs are examined in detail. The genetic basis of disc degeneration is presented. The hypothesis is that such degeneration leads to a loss of normal stiffness in the segments affected leading to abnormal mechanical behaviour which in turn leads to pain. The evidence for this is presented. The development of surgical solutions to relieve back pain, from fusion through first generation mechanical artificial discs to elastomeric designs, is traced. The author‘s personal contributions to this area of knowledge are set out. The appreciation of the requirement for a restoration of physiological stiffness is argued throughout, showing where fusion and first generation discs have not met the clinical aim of pain relief, because they have not restored physiological stiffness. The path to an elastomeric, viscoelastic, polyhydrocarbon, rubber solution in the form of the “Freedom“ disc has filled 17 years of the author‘s academic pursuits. It will be shown that this technology may represent a possible solution to the clinical problem. Failure is part of all new advancement and this too is presented, to show how that has influenced thinking, producing original ideas to overcome these failures. Providing lessons are learned from these failures then our patients in the future will benefit.

A clinical study was performed in order to determine if healthy test subjects can differentiate between adjacent and separated pairs of vertebrae in the lumbar spine. The variable of interest was number of correctly specied pairs of vertebrae. The test subjects were evaluated in terms of sensitivity and specicity of this test. Bootstrap resampling was applied in the data analysis. The results clearly indicated that the test subjects in this study were able to successfully determine whether a pair of adjacent or separated vertebrae was tested during the procedure.

In developing a method of quantifying stability in the lumbar spine Cholewicki and McGill (1996) have also broached the notion of sufficient stability, where too much stiffness (and stability) would hinder motion. Thus people highly skilled at maintaining stability may use different and optimal strategies, where <i>sufficient</i> stability is maintained. The purpose of this work was to explore the contributors to <i>sufficient</i> stability, how they coordinate and relate to injury mechanisms. This work represents a cascade of investigations where. 1) To explore the balance of various sources of stiffness and their effect on the critical load and post-buckling behaviour, simulations were undertaken where the buckled configuration of the spine was predicted and its stability in this new configuration was assessed. 2) The various sources of stiffness contributing to stability in the lumbar spine have been in some cases found to be deficient. The question of how these deficiencies place individuals at risk of instability, if at all, remains unresolved. A challenged breathing task was used to determine if there was a difference in stabilizing potential between healthy individuals and low back pain sufferers. Given that differences in stabilizing potential are apparent, several tasks which included a predetermined motor strategy, such as 3)pressurizing the abdomen and 4) abdominal hollowing vs. muscle bracing, were evaluated to determine if individuals can utilize motor strategies to augment stability. The stabilizing potential of abdominal pressure (IAP) and its interaction with muscle activation was evaluated. Some individuals are more skilled at stabilizing their lumbar spine than others. Some consciously controlled motor strategies are better stabilizers than others. These strategies highlight the relative contributions of various components (posture, passive tissue, muscle activation, and load) in that no single muscle dominates stability and IAP appears to augment stability beyond muscle activation alone. The margin of safety is considerable and depends on the task at hand, but it is possible to speculate on which tissues are at greatest risk of injury.

A dissertation submitted in partial compliance with the requirements for a Master's Degree in Technology: Chiropractic, Durban Institute of Technology, 2005. / Low back pain has been shown to be associated with inhibition of the lower limb musculature. This inhibition is called arthrogenic muscle inhibition (AMI). Sacroiliac joint dysfunction has been linked with AMI of the ipsilateral and contralateral quadriceps and hamstring muscles. Sacroiliac manipulation has been shown to significantly reduce ipsilateral AMI, however no studies have been conducted to illustrate the effect of sacroiliac manipulation on contralateral AMI. Neither have their been studies to show the presence or extent of spinal dysfunction between the levels of L2-L5 and its significance on muscle inhibition in the quadriceps and hamstring muscles, nor the effect of manipulation of these levels on AMI of the quadriceps and hamstring muscles. The purpose of this study was therefore to determine whether spinal manipulation has an effect on AMI of the contralateral limb as well as that of the ipsilateral limb. / M

The lumbar motor activity in isolated spinal cords of 72 postnatal Balb/C mice aged 2, 5, 10 and 21 days (PN2-21) was electroneurographically recorded (ENG) via bilateral ventral roots following treatment with three different concentrations (25, 100 and 200 pM) of the neurotransmitter, 5-hydroxytryptamine (5-HT), i.e., serotonin, to determine its effects on spinal pattern generation.