Differences in repositioning error among patients with low back pain compared with control subjects

STUDY DESIGN: Trunk repositioning error was measured in 20 patients with chronic low back pain and 20 control subjects. OBJECTIVES: To measure trunk repositioning error as a method of measuring proprioception of the low back and to compare trunk repositioning error in patients with low back pain and in control subjects. SUMMARY OF BACKGROUND DATA: Although many current low back pain rehabilitation programs incorporate proprioceptive training, very little research has been performed on proprioception of the low back. METHODS: While standing with the legs and pelvis immobilized, the subject bent the trunk to a predetermined target position and then attempted to replicate the position. Repositioning error was calculated as the absolute difference between the actual target position and the subject-perceived target position. The multiple target positions in the frontal and sagittal planes were tested. Trunk position was measured with a 3Space Tracker, which analyzes the three-dimensional position of the body. RESULTS: Repositioning error in patients with low back pain was significantly higher than that of control subjects in flexion, and significantly lower than that of control subjects in extension. CONCLUSIONS: The increase in repositioning error of patients with low back pain during flexion implies that some aspects of proprioception are lost in patients with low back pain. The decrease in repositioning error in patients with low back pain in extension is not as easily explained, but could possibly be caused by increased activation of mechanoreceptors in facet joints.     

Spine loading characteristics of patients with low back pain compared with asymptomatic individuals.

STUDY DESIGN: Patients with low back pain and asymptomatic individuals were evaluated while performing controlled and free-dynamic lifting tasks in a laboratory setting. OBJECTIVE: To evaluate how low back pain influences spine loading during lifting tasks. SUMMARY OF BACKGROUND DATA: An important, yet unresolved, issue associated with low back pain is whether patients with low back pain experience spine loading that differs from that of individuals who are asymptomatic for low back pain. This is important to understand because excessive spine loading is suspected of accelerating disc degeneration in those whose spines are damaged already. METHODS: In this study, 22 patients with low back pain and 22 asymptomatic individuals performed controlled and free-dynamic exertions. Trunk muscle activity, trunk kinematics, and trunk kinetics were used to evaluate three- dimensional spine loading using an electromyography- assisted model in conjunction with a new electromyographic calibration procedure. RESULTS: Patients with low back pain experienced 26% greater spine compression and 75% greater lateral shear (normalized to moment) than the asymptomatic group during the controlled exertions. The increased spine loading resulted from muscle coactivation. When permitted to move freely, the patients with low back pain compensated kinematically in an attempt to minimize external moment exposure. Increased muscle coactivation and greater body mass resulted in significantly increased absolute spine loading for the patients with low back pain, especially when lifting from low vertical heights. CONCLUSIONS: The findings suggest a significant mechanical spine loading cost is associated with low back pain resulting from trunk muscle coactivation. This loading is further exacerbated by the increases in body weight that often accompany low back pain. Patient weight control and proper workplace design can minimize the additional spine loading associated with low back pain.     

Predicting outcomes of neuroreflexotherapy in patients with subacute or chronic neck or low back pain

Background contextIn the context of shared decision-making, a valid estimation of the probability that a given patient will improve after a specific treatment is valuable.PurposeTo develop models that predict the improvement of spinal pain, referred pain, and disability in patients with subacute or chronic neck or low back pain undergoing a conservative treatment.Study design and settingAnalysis of data from a prospective registry in routine practice.Patient sampleAll patients who had been discharged after receiving a conservative treatment within the Spanish National Health Service (SNHS) (n=8,778).Outcome measuresSpinal pain, referred pain, and disability were assessed before the conservative treatment and at discharge by the use of previously validated methods.MethodsImprovement in spinal pain, referred pain, and disability was defined as a reduction in score greater than the minimal clinically important change. A predictive model that included demographic, clinical, and work-related variables was developed for each outcome using multivariate logistic regression. Missing data were addressed using multiple imputation. Discrimination and calibration were assessed for each model. The models were validated by bootstrap, and nomograms were developed.ResultsThe following variables showed a predictive value in the three models: baseline scores for pain and disability, pain duration, having undergone X-ray, having undergone spine surgery, and receiving financial assistance for neck or low back pain. Discrimination of the three models ranged from slight to moderate, and calibration was good.ConclusionsA registry in routine practice can be used to develop models that estimate the probability of improvement for each individual patient undergoing a specific form of treatment. Generalizing this approach to other treatments can be valuable for shared decision making.     

The effect of psychosocial measures of resilience and self-efficacy in patients with neck and lower back pain

Background Context

Psychosocial risk factors may predispose to progression of back and neck pain to chronic pain or disability. Resilience (the ability to recover from stress) and pain self-efficacy (confidence that one can perform daily activities despite pain) are important psychometric properties shown to affect health and illness.

Predictors of isokinetic back muscle strength in patients with low back pain

STUDY DESIGN: Testing for trunk muscle strength was performed on 105 patients with chronic low back pain. OBJECTIVES: To investigate prediction of isokinetic back muscle strength in patients with low back pain. SUMMARY OF BACKGROUND DATA: The clinical evaluation of patients with chronic low back pain often in difficult because of discrepancy between disability and impairment. The isokinetic trunk device was developed as a tool for objective assessment of back muscle strength. However, the performance of patients depends on radiologic abnormalities of the spine, conditions of the back muscles, and various psychosocial factors. Studies are warranted that address how these variables influence back muscle strength. METHODS: The patients with chronic low back pain were tested by an isokinetic trunk muscle strength test (Cybex TEF, Ronkonkoma, NY). In addition, the following variables were recorded: gender, age, body mass index, emotional distress, pain on exertion, self-efficacy for pain, degenerative changes of the lumbar spine, cross-sectional area, and density of the erector spinae muscles. The three latter variables were estimated by computed tomography scans. The sum of the total work performed during isokinetic extension strength test was the dependent variable in a multiple regression analysis, and anthropometric, demographic, psychological, and radiologic factors were independent variables. RESULTS: Gender, cross-sectional muscle area, and pain on exertion were the most powerful predictors of isokinetic back muscle strength. The final regression model, which included these variables, could account for approximately 40% of the variability in back muscle strength. CONCLUSION: For assessing the results of an isokinetic trunk muscle strength test, cross-sectional muscle area, gender, and pain on exertion should be taken into account.     

Outcome research in patients with chronic low back pain

Outcome research in chronic low-back pain is entering a new phase. In the past several years, several outcome measures have been evaluated for their psychometric properties, and databases for patients with low-back pain exist for some of them. A set of recommended and standardized outcome measures and questionnaires is now available for the different outcome domains. The use of computerized versions of these questionnaires will allow simplified data collection and analyses, which will not only help to formulate a more uniform design of research trials, but can be useful for clinicians interested in documenting multi-dimensional outcomes in their patient population.     

The association between physical activity and neck and low back pain: a systematic review

The effect of physical activity on neck and low back pain is still controversial. No systematic review has been conducted on the association between daily physical activity and neck and low back pain. The objective of this study was to evaluate the association between physical activity and the incidence/prevalence of neck and low back pain. Publications were systematically searched from 1980 to June 2009 in several databases. The following key words were used: neck pain, back pain, physical activity, leisure time activity, daily activity, everyday activity, lifestyle activity, sedentary, and physical inactivity. A hand search of relevant journals was also carried out. Relevant studies were retrieved and assessed for methodological quality by two independent reviewers. The strength of the evidence was based on methodological quality and consistency of the results. Seventeen studies were included in this review, of which 13 were rated as high-quality studies. Of high-quality studies, there was limited evidence for no association between physical activity and neck pain in workers and strong evidence for no association in school children. Conflicting evidence was found for the association between physical activity and low back pain in both general population and school children. Literature with respect to the effect of physical activity on neck and low back pain was too heterogeneous and more research is needed before any final conclusion can be reached.     

Corticospinal excitability in patients with chronic low back pain

OBJECTIVE: This study was designed to investigate corticospinal excitability of lumbar muscles using transcranial magnetic stimulation (TMS) in patients with chronic low back pain and correlate this with self-rated measures of disability and pain. METHODS: Twenty-four patients with chronic low back pain and 11 healthy control subjects were used in this study. TMS was delivered through an angled double-cone coil, with its cross-over on the vertex and a posterior-to-anterior current flow in the brain. Electromyographic (EMG) recordings were made from erector spinae (ES) muscles at the fourth lumbar level. Motor cortical excitability was assessed using motor threshold (MTh) for motor evoked potentials (MEPs) and threshold for silent period (SP) during facilitation of the back muscles. Latency, duration, and area of MEPs and SPs were also measured. RESULTS: The latency, duration, and size of MEPs and SPs did not differ between the left and right ES muscles in either the patients or the control subjects and also did not differ between the patients and the control subjects. However, there was a significantly higher MTh and threshold for the SP in the patients as compared with the control subjects; the full significance of this requires further investigation. Interestingly, there was a positive correlation between the self-rated measure of disability (the Oswestry Disability Index score) and both the MTh and the threshold for the SP in the patients. There was also a positive correlation between the self-rated index of back pain and the threshold for the SP in the patients. This finding of an association between clinical and neurophysiologic measures reinforces the need for further research to establish the clinical relevance of these rises in MTh and SP threshold. CONCLUSIONS: In summary, this study has revealed that corticospinal excitability, driving ES muscles close to the site of pain, is lowered in patients with chronic low back pain.     

Femoral neck stress fracture presenting as low back pain

Femoral neck stress fractures in young adults are uncommon and usually not considered in the differential diagnosis of low back pain. However, if the patient has groin and anterior thigh pain, it is important to thoroughly examine the hips. To illustrate this point, we present a patient with a femoral neck stress fracture who was misdiagnosed as having mechanical back pain.     

JOSPT perspectives for patients. Low back pain: MRIs should be used sparingly in patients with low back pain

Low back pain is very common, with 80% of people experiencing back pain at least once in their lifetimes. The good news is that a thorough physical examination can often determine the best course of management and whether you require imaging to rule out a serious problem. Often low back pain can be severe enough to make a patient think that an MRI is necessary. While MRI provides excellent pictures of your anatomy, it may not be able to pinpoint the specific source of your pain. A clinical commentary published in the November 2011 issue of JOSPT summarizes research that describes how the increased use of unnecessary imaging may lead to less than favorable results.     

A review of psychological risk factors in back and neck pain

STUDY DESIGN: The literature on psychological factors in neck and back pain was systematically searched and reviewed. OBJECTIVES: To summarize current knowledge concerning the role of psychological variables in the etiology and development of neck and back pain. SUMMARY OF BACKGROUND DATA: Recent conceptions of spinal pain, especially chronic back pain, have highlighted the role of psychological factors. Numerous studies subsequently have examined the effects of various psychological factors in neck and back pain. There is a need to review this material to ascertain what conclusions may be drawn. METHODS: Medical and psychological databases and cross-referencing were used to locate 913 potentially relevant articles. A table of 37 studies was constructed, consisting only of studies with prospective designs to ensure quality. Each study was reviewed for the population studied, the psychological predictor variables, and the outcome. RESULTS: The available literature indicated a clear link between psychological variables and neck and back pain. The prospective studies indicated that psychological variables were related to the onset of pain, and to acute, subacute, and chronic pain. Stress, distress, or anxiety as well as mood and emotions, cognitive functioning, and pain behavior all were found to be significant factors. Personality factors produced mixed results. Although the level of evidence was low, abuse also was found to be a potentially significant factor. CONCLUSIONS: Psychological factors play a significant role not only in chronic pain, but also in the etiology of acute pain, particularly in the transition to chronic problems. Specific types of psychological variables emerge and may be important in distinct developmental time frames, also implying that assessment and intervention need to reflect these variables. Still, psychological factors account for only a portion of the variance, thereby highlighting the multidimensional view. Because the methodologic quality of the studies varied considerably, future research should focus on improving quality and addressing new questions such as the mechanism, the developmental time factor, and the relevance that these risk factors have for intervention.