Fear of Movement and Low Back Pain

Fear-avoidance behavior has been widely acknowledged among chronic low back pain (LBP) patients. "The central concept of these models is fear of pain, or the more specific fear that physical activities will cause (re)injury. Patients may react to these fears either with 'confrontation' or 'avoidance.'" This current study was designed to see if the fear that patients felt about their back pain translated into a physiological reaction. The authors started with the following hypotheses:

• Highly fearful patients will report more tension than low fearful patients.
• Fear of movement or re-injury predicts an increase in lower paraspinal muscle reactivity during the video presentation.
• Negative affectivity (NA), which is defined as a tendency to experience subjective distress and dissatisfaction, moderates the fear's effect on reactivity.
• Increased reactivity correlates with increases in pain reports during physical performance, and this is also moderated by NA.

The 31 participants were chosen because they had "minimal organic findings or displayed pain complaints that were disproportionate to the demonstrable organic basis of their pain." The authors distributed questionnaires that measured pain-related fear, negative affect, pain intensity, and perceived tension.

First, the subjects had an EMG of the lower paraspinal muscles while they were watching a video. The video exposure had two segments: the first was a 60-second nature documentary. Before viewing the second, the patients were told they would have to perform what they saw after its completion. Two activities were shown: a person vigorously riding a stationary bike, and exercise measuring extension-flexion. The actor in the video was displaying pain behaviors—groaning, sighing, and gasping. The EMG was in place while the patients were watching, and after the video, the researchers measured tension, intensity, and pain. Immediately after watching these videos of the suffering actors, the participants were led into a room with the exercise equipment.

The authors categorized patients in a "high fearful" and "low fearful" group. The high-fear group had higher scores of tension, and coincidentally, had higher baseline EMG readings in the paraspinal muscles. There were not any significant differences in muscular reactivity between the two groups for any of the muscles. Generally, muscular reactivity decreased during the video exposure. The authors explain that perhaps their reactivity was affected by the experimental setting, feeling safe, and therefore, able to withdraw during the experiment.

The patient's fear of movement was only predictive of reactivity levels of the left erector spinae. But, pain duration turned out to be the predictive model for reactivity of the left paraspinal muscles. The authors write, "This suggests that muscular reactivity associated with pain-related fear occurs early on in the development of chronic pain. An alternative explanation is that patients with longer pain duration are likely to be more disabled, and therefore more easily might have decided to ignore the instructions during the video-exposure."

Negative affect held some predictive power. In symptom-specific reactivity, NA did not moderate, but in both tibialis anterior muscles it did have an effect. Mainly, pain-related fear would predict muscular reactivity in high NA effect patients.

The authors summarize their findings:

"This study is the first to show that the symptom-specific model of psychophysiological reactivity in chronic pain also applies to the domain of pain-related fear. Although of relatively short duration, reactivity of the left paraspinal muscles is also associated with subsequent pain during a physical activity. In addition, we were able to show that in patients who report high NA, pain-related fear also influences muscular reactivity in other muscles as well."

Vlaeyen JWS, Seelen HAM, Peters M, et al. Fear of movement/(re)injury and muscular reactivity in chronic low back pain patients: an experimental investigation. Pain 1999;82:297-304.

Fear of Pain More Disabling than Actual Pain

Fear of pain can disable a patient in many ways. Previous literature has reported that the fear of pain induces avoidance behavior (which lends to low physical activity), interferes with cognitive functioning, and that long-standing avoidance and disability eventually affects physiological systems. The authors of this study, performed three separate studies to investigate pain related fear. The first assessed if pain-related fear is more disabling than pain itself; the second looked to see if there is an association between fear and poor work performance; and the third compared pain related fear measures and general mental health to assess which was a better predictor of disability and performance.

The first inquiry consisted of 35 chronic low back pain patients. The participants self-reported their disability by replying to questionnaires that evaluated current pain intensity, pan-related fear, disability and general negative affect. The findings revealed that disability significantly correlated to pain-related fear scores, but not to pain intensity or negative affect scores—pain-related fear was a better predictor of disability than the other two.

In investigating the role of pain severity, pain related fear, pain anticipation, and negative affect's role in predicting performance the authors found, surprisingly, that none of the pain-related fear measures correlated to the patients' level of pain expectancy. What emerged as a predictor of decreased performance was the expectation of pain, not the actual pain experienced.

With 31 chronic low back pain patients the authors finally examined pain severity, pain-related fear, and negative affect scores to predict self-reported disability and behavioral performance. The authors found that if patients' pain occurred suddenly the pain related fear was higher; if patients' pain developed gradually the disability scores were higher. Also pain-related fear was more predictive of physical performance than the current pain intensity or increase. And as other studies have implied, the low back pain patients' physical performance was significantly influenced by the presence of pain radiating in at least one leg.

These findings indicate pain-related fear is a solid predictor of a patient's performance and self-perceived disability. Since it plays such a major role, the authors attempt to answer what, exactly, these patients fear. They offer three possibilities:

• Pain-related fear is more related to the long-lasting effects of physical activity rather than to immediate pain increases during the activity.
• Patients avoid physical activity out of fear of additional harm, injury, or re-injury.
• Patients may fear they could not cope with pain increase.

As well, the authors than provide a plan to handle chronic low back pain patients, or any patients with high levels of pain-related fear:

1. Screening: Identifying the patient early in treatment is recommended. The authors suggest using both the TSK [Tampa Scale for Kinesiophobia] and FABQ [Fear-Avoidance Beliefs Questionnaire], which were used in this study, because, "they are relatively short questionnaires that can be easily used in a primary care setting." During the screening process, it is worthwhile to determine what the patient is actually afraid of—abrupt movement? Spinal compressions? Damaged nerves?
2. Education: Directly and clearly explaining to the patient that their pain is a common condition that can be self-managed and not a disease/condition that needs constant care and attention. The authors stipulate the point of the educational portion is not to lecture, but to simply explain to the patient that their condition can be improved by increased activity.
3. Exposure: The most important step—getting the patient involved in a concrete plan that gradually resumes their normal activities. The authors write, "Such an exposure is quite similar to the graded activity programs, in that it gradually increases activity levels despite pain, but is dissimilar in that it pays special attention to the personally-relevant and pain related stimuli."

The authors conclude that since fear of pain gauged in as a powerful psychological challenge for chronic disability additional studies are needed to understand all the mechanisms that lead to chronic pain and disability.

Crombez G, Vlaeyen JWS, Heuts PH, Lysens R. Pain-related fear is more disabling than pain itself: evidence on the role of pain-related fear in chronic back pain disability. Pain 1999;80:329-339.

Job Satisfaction and the Transition from Acute to Chronic Back Pain

In the current medical literature there is ongoing debate as to whether job satisfaction is a predictor or consequence of back pain and disability. The researchers in this study approached the dilemma by evaluating job satisfaction's role in the transition from an acute onset of pain to a chronic problem in patients without prior back pain histories. The authors' hopes were that if factors that cause chronicity could be pinpointed early, interventions could be implemented that would curb the duration of pain and disability.

82 men were assessed with tests evaluating their pain, disability, psychological distress, orthopedic impairment, and job satisfaction at the onset, two months, and six months. Their findings suggest job satisfaction may be a factor in the transition from an acute episode to a persisting condition:

"Greater job satisfaction at the time of initial back pain predicted better overall clinical outcome 6 months later, including reduced pain and disability after controlling for baseline levels of these factors and current orthopedic impairment. There also was a trend for greater job satisfaction to predict reduced psychological distress at six months after controlling for initial psychological distress and current orthopedic impairment."

Also, job satisfaction, type of work performed, and social position were factors influencing the study; but, 6 months later only job satisfaction was predicative of outcome. Therefore, the authors conclude that job satisfaction is not a consequence of the other factors, and may protect against pain episodes by offering an incentive to continue working.

Williams RA, Pruitt SD, Doctor JN, et al. The contribution of job satisfaction to the transition from acute to chronic low back pain. Archives of Physical Medicine and Rehabilitation 1998;79:366-374.

Neck and Back Pain in Schoolchildren: The Role of Backpacks

Public health experts have recognized for many years that excessively heavy backpacks can cause back and neck pain in children.  Three new studies have recently been published on this issue, and they shed some light on prevention of back pain in children.

Physical and Psychological Factors in Children with Back Pain

This British study¹ was designed to examine ergonomic and other factors that might account for back and neck pain in schoolchildren.

The authors gave questionnaires to 697 children aged 11-14. Of these students, 27% reported having neck pain, 18% reported having upper back pain, and 22% reported having low back pain.

After analysis of the collected data, the authors found the following:

• Neck pain was linked to school furniture, emotional and conduct problems, family history of low back pain and previous treatment for musculoskeletal disorders.
• Upper back pain was associated with backpack weight, school furniture, emotional problems, and previous treatment of musculoskeletal pain.
• Low back pain complaints were associated with school furniture, emotional issues, and “family history and previous injury or accident.”

Effects of Backpack Weight on Posture

This Italian study² looked at 43 students with an average age of 12.5 years. The authors tested each of the children with an 8-kg and 12-kg backpack, and they had the children wear them over one shoulder and two shoulders. Posture was evaluated on the children while they did a 7-minute treadmill walk.

The authors found that the posture of the children was substantially altered under load. Not surprisingly, asymmetrical loading (carrying the backpack on one shoulder rather than both), resulted in the most complex postural changes.

“Our results suggest that a 12 kg load, fairly common in this population (carried at least once a week), seems to push the postural system to its physiological limits.” ²

They found that the postural changes were corrected once the load was removed, but the long-term consequences of these excessive weights are unknown.

Limit Backpack Weight to 10% of Child’s Body Weight

In the third report,³ the researchers interviewed 531 children from 5th to 12th grade and weighed the backpack of each student. The found that:

• “Younger students and females are more at risk due to relatively lower body weight...”
• Female students carried heavier backpacks than did male students.
• “Greater relative backpack weight is associated with upper– and mid–back pain reports but not neck or lower back pain; it is also associated with lost school time, lost school sports time, and greater chiropractic utilization.”

The authors of this study recommend that backpacks weigh no more than 10% of the child’s body weight, which is lower than the current recommendation of 15%. Previous studies have found that students often carry between 17-22% of their body weight. ²

From these studies, it’s clear that a significant number of children suffer from neck and back pain. Because a substantial portion of these complaints may originate in backpack usage, it is critical when dealing with children with neck and back pain to ask about backpack usage. Musculoskeletal pain in children is especially a concern since it has been associated with pain in adulthood.

1. Murphy S, Buckle P, Stubbs D. A cross-sectional study of self-reported back and neck pain among English schoolchildren and associated physical and psychological risk factors. Applied Ergonomics 2007;38(6):797-804.
2. Negrini S, Negrini A. Postural effects of symmetrical and asymmetrical loads on the spines of schoolchildren. Scoliosis 2007;2(1):8.
3. Moore MJ, White GL, Moore DL. Association of Relative Backpack Weight With Reported Pain, Pain Sites, Medical Utilization, and Lost School Time in Children and Adolescents. Journal of School Health 2007;77(5):232-239.

Physical Risk Factors and Back Pain

This prospective general population study hoped to determine if non-occupational physical factors increased the risk of new episodes of low back pain (LBP). The authors looked at 2,715 subjects who had no back pain during the previous 30 days. The researchers evaluated their overall health, stress on the spine (in terms of weight, height, and activity), smoking status, psychological stress, and self-rated physical activity.

A year later, the authors followed up with another survey if the patient did not consult a physician in those 12 months. 1,540 patients responded to the follow-up survey; the 1066 who did not reply tended to be younger, less physically active, and more likely a smoker.

594 of 1649 (36%) had experienced an episode of low back pain. 254 patients reported their first episode ever. 37% of the men and 48% of the women who had a back pain episode had their first encounter with LBP over the 12-month period.

In comparing incident rates and surveys, the authors concluded that a poor rating of overall health at the initiation of the study predicted a new occurrence of back pain in the following year—regardless of the patient's history with the condition. As well, the risk for women increased with heavier weight. Yet, they also found factors which did not influence the probability of a future episode: Current smokers were no more likely to have an episode than former smokers or nonsmokers, and less physically active participants were no more likely to have an episode than more physically active subjects. The authors conclude:

"The major risk for new episodes of low back pain identified in the current prospective investigation, apart from poor self-rating of physical health, was excess weight in women. The extent to which physical activity aids weight control, may protect against low back pain in the long-term, and is beneficial for other reasons is an argument for promoting it in general. To complement this argument, this observational study has provided evidence that physical activity outside the workplace does not constitute a major hazard for low back pain in the short term."

Croft PR, Papageorgiou AC, Thomas E, et al. Short term physical risk factors for new episodes of low back pain. Spine 1999;24(15):1556-1561.

Back Pain, Fibromyalgia, and the Stress Response System

In this study, researchers examined three groups of subjects—a set of 40 fibromyalgia (FM) patients, a set of 28 chronic low back pain (LBP) patients, and 14 healthy controls. All groups of subjects underwent a thorough laboratory examination.

The researchers found that FM patients had the most dysfunction in the stress response system, but that LBP patients had some of the same characteristics.

"From a clinical point of view, it is our impression that in individual cases FM, over the years, often ensues from LBP or other localized pain disorders...In view of the notion that patients with FM and LBP both experience chronic pain, that FM can develop after LBP, and that both disorders display rather similar neuroendocrine abnormalities (albeit to a different degree), one might conclude that the pain in FM is the primary factor underlying its pathogenesis."

What is clear from this study is that both FM and LBP patients exhibit disruption of the neuroendocrine system, especially in the system that controls how the body responds to stress. Similar dysregulation has been found in patients with PTSD, depression, and chronic fatigue syndrome.

Griep EN, Boersma JW, Lentjes EG, et al. Function of the hypothalamic-pituitary-adrenal axis in patients with fibromyalgia and low back pain. The Journal of Rheumatology 1998;25:1374-1381.