News Category: Pain

New research published in Science shows that people exposed to pain dread it so much they will take a higher dose of pain sooner than later to avoid waiting for the pain to occur at an unknown time.

For example, in this study 32 volunteers received an electric shock. A clock showed how much time would go by before the next shock. Most of the subjects chose a higher shock with a shorter delay. They dreaded the wait so much they made the trade off at least 50 per cent of the time.

MRIs of the brain during the study mapped out the neuro-response. The results showed subjects weren’t afraid of the shock. They just couldn’t stand to wait for it. This state of “dread” or state of unpleasant waiting did not create brain patterns normally seen with fear or anxiety.

It’s not clear yet how this information will help in the treatment of pain patients. Researchers suggest patients may make treatment choices that don’t always make sense. Some patients may seek treatment that will cause more pain earlier in the course of treatment to avoid waiting for symptoms to come back.

Working with patient expectations may be a key to successful treatment. More study is needed before we will know how to do this.

What are the effects of chronic pain on driving during normal traffic? That’s the topic of this study from the Netherlands.

Many people think that when someone has pain every day they get used to a certain amount of discomfort. It no longer affects the way that person performs including driving a car. However, several studies have shown problems with attention and speed control in the lab when testing patients with chronic pain. Other studies show no such problems.

In this study two groups of people were included. The first group (14 subjects) of healthy adults were the control group. The second group of 14 patients had nonmalignant pain rated as “moderate” and lasting at least three months. All participants took an on-the road highway driving test. They also took tests in a lab of IQ, memory, and tracking skills.

The results of this study show a lower IQ for pain patients and worse highway driving performance. The analysis of the data didn’t show a link between these two results. Tests for depression and coping showed no differences between the two groups. Pain patients reported a lower quality of life compared to healthy subjects.

Overall chronic pain patients showed impaired driving skill similar to what is seen in healthy adults with a blood alcohol level of 0.08 percent. This is enough to increase the risk of causing an accident by three times the normal number. Memory and attention are affected the most by alcohol or pain.

The authors conclude pain does affect driving ability. The level of pain (mild, moderate, severe) doesn’t seem to make a difference. More studies are needed to find out which pain patients are affected most and the difference in performance between highway and city driving.

hanks to advances in pain control, shoulder surgery can be done on an out-patient basis. Interscalene nerve blocks, a form of regional anesthesia has made the postoperative period much easier. Pain is blocked after surgery from the upper neck to the elbow. There is less nausea, and the patient is more alert and able to move. These two factors allow for earlier discharge.

But there are some disadvantages to the nerve block. Sometimes the patient loses motor control and function until the block wears off. Nerve damage can occur but remains unknown in the recovery room. In this study, researchers compared the nerve block to a patient-controlled pain device and report the results.

All patients in both groups had shoulder surgery under general anesthesia by the same surgeon. The operations were done on an outpatient basis. Several different types of surgical procedures were done including rotator cuff or labral repairs, subacromial decompression, and joint manipulations.

Regional anesthesia lasted in the nerve block group for about six to eight hours after surgery. Patients using the pain-control analgesia (PCA) were told to push the button on the device whenever they felt pain. A small amount of lidocaine (numbing agent) was released into the joint with each push of the button.

Patients using the PCA slept better with fewer awakenings the first night after surgery. They were also more active during the first few days and took fewer pain meds. The authors conclude PCA is safe and effective for use after arthroscopic shoulder surgery. It can be used as an alternative when the interscalene block isn’t available or can’t be used.

Take two people with the same back injury. Why does one get better and the other gets worse?

Scientists think fear of pain may have something to do with it. A theory called the fear-avoidance (FA) model of pain has been proposed. Fear of pain or reinjury changes the way the person moves. They may avoid any movements that might cause pain. FA leads to disuse, depression, and disability.

In this study, researchers compare FA responses of adults to chronic pain by age. They used the Tampa Scale of Kinesiophobia (TSK) to test for fear of movement/(re)injury. They found that the TSK was the best fit for chronic pain patients divided into groups by age.

Older adults (55 years old and older) had less pain-related fear compared to middle-aged or younger adults. But when present, the fear of (re)injury was more likely to lead to depression and disability in older adults.

Young patients are more likely to “catastrophize” their pain. Their negative thinking exaggerates pain. Catastrophic thinking fuels fear leading to greater disability when compared to patients who don’t catastrophize.

The authors conclude by saying the results of their study confirm the FA theory. Fear of pain does predict who will become a chronic pain patient. In fact fear of pain is a better predictor of disability than pain itself. FA tests can help show who will be disabled six months from now. Education may help prevent or at least reduce pain-related fear.

Doctors have concerns about the use of addictive drugs (opioids) such as morphine used for pain. Tolerance and physical dependence can occur when used over a period of time. Animal studies have shown that genetics have an effect on tolerance and dependence. In this study, researchers use mice to look at how pain affects opioid tolerance and dependence.

Two groups of eight mice were included in the study. The test group was given an injection in one paw to cause an inflammatory reaction. The control group was not injected. Then mice in both groups were injected once each day for four days with morphine. The amount of drug given was increased each day.

A drug (Narcan) was used to cause withdrawal from opioids. Narcan works by blocking the cell receptors for opioids. Without the opioids, the body goes into withdrawal. Physical dependence on morphine was measured by counting the number of jumps the mice made for 15 minutes after the Narcan was given.

Different strains of mice had different reactions to the morphine and morphine withdrawal. For example, in the control group some mice jumped less than one time in 15 minutes. Others jumped more than 90 times during the same period. In the test group jumping behavior increased in three-fourths of the mice and decreased in the remaining one-fourth.

What this study shows is that mice that are in pain when given morphine develop an increased tolerance for the drug. This means the effects of opioids on pain were less over time. The mice needed more drug to get the same analgesic effect.

The large differences among strains of mice suggest genetics do play a role in pain response to opioids. The authors conclude both chronic pain and genetics change the “patient’s” (mice) response to morphine, tolerance, and physical dependence on the drug.

It’s hard to concentrate when you’re in pain. Research shows that pain is a stressor to the body. The mind diverts energy and resources to process that pain all the while the person is trying to do a task.

Chronic pain patients face this problem everyday. It’s called attentional processing. But are their attention deficits due to sharing of resources? Or does the mind/body switch from one to the other? That’s the focus of this study.

Fourteen (14) patients with chronic pain rated as moderate-to-severe were compared to 30 healthy controls who had no pain. Two tasks were given: one was easy, the other difficult. In the easy task everyone was shown a colored rectangle. They were told to push one button if the rectangle was blue and another button if it was some other color.

In the difficult task the subjects were shown rectangles of different sizes. They had to keep a running memory of two rectangles at a time to compare whether they were equal in size. They were also shown pictures in between tests. No response was required to the pictures. They just had to pay attention to each one.

The chronic pain group was faster in responding but made more mistakes compared to the control group. It seems they traded accuracy for speed and made more impulsive responses. This was true for both the easy and the more difficult tasks. They were also more distracted by the extra stimuli (pictures shown).

The authors conclude that pain patients don’t have a shortage of resources to process information and to do tasks. Instead they have abnormal use of their ability to pay attention. In other words, they can’t use their full attention on a task when they are in pain. Patients who used morphine-based pain relievers had better results. Future studies may help find the best way to control pain while restoring cognitive function.

Pain management before and after neurosurgery is a challenge for most doctors. In this study, pain patterns are described for different kinds of brain and spine operations. Understanding pain patterns may be the first step before pain therapy can be determined.

Data on pain patterns before and after surgery was collected for 649 neurosurgery patients. Neurosurgery included any operation on the skull or spine. Patients were asked about pain location, frequency, intensity, and duration. Researchers compared patients with and without complications. Pre- and postop pain patterns were described.

Patients also reported on local versus referred pain. Local pain occurs at the site of the operation. Referred pain is felt some distance away from the cause.

Results from this study showed that pain didn’t depend on gender. In other words, pain intensity wasn’t linked with whether the patient was male or female. Age did seem to make a difference. Younger patients had less pain before surgery and more pain after the operation compared to patients 60 years old and older.

Problems after surgery such as infection or delayed healing usually resulted in more pain. As expected, pain levels went down after surgery as time went on. Operations on the skull tend to have less pain than spinal surgery. Most patients having spine surgery expected more pain relief after the operation than they actually got. Patients who had pain before the operation had more postoperative pain compared to patients who didn’t have pain before.

The authors offer several guidelines for managing pain after neurosurgery. Nurses and doctors should be aware that these operations are more painful than expected by the patient. Drugs for pain should be given on the first day after the operation for most neurosurgeries. Some patients will need more intense drug therapy after that.

Pain should be treated seriously in all patients. But both patients and health care workers shouldn’t be surprised if the pain relievers don’t reduce pain levels. Stronger pain meds may be needed. Patient-controlled analgesia (PCA) is a good option for some patients.

How accurate is memory recall for pain? Some studies say the level of remembered pain is accurate; others say pain recall is distorted. In this study researchers show that pain is exaggerated over time when it is linked with a negative emotion.

Healthy adults were exposed to temperatures cold enough to cause intense, acute pain. The pain was similar to an “ice cream headache.” Saliva was collected before and after the experiment to measure cortisol levels. Cortisol is a hormone released when a person is having a painful experience. It can be used as a measure of stress.

Forty-three healthy adults were included in this study. Cortisol and pain levels were measured before, during, and after the painful stimulus. Mood was also tested before and right after. Follow-up testing of mood and memory or recall of pain levels were re-measured nine months later.

Subjects remembered the maximum pain intensity later as being greater than reported at the time of the pain. This is called post-exposure pain modulation. This study confirms that a negative experience (painful test) results in a heightened memory of pain later. If this cold test was done again, the memory of the first experience would lead to a higher pain rating the second time.

The authors conclude these findings may help in a clinical setting. Patients who have painful procedures may be able to reduce the pain when these procedures are repeated. For example using stress management techniques during bone marrow aspiration or spinal tap may reduce the initial perception of pain. Then future repeats of the same treatment may not be so painful. The same may be true for patients having other repeated painful events such as biopsy or radiation.

Pain as a result of a work-related injury is a good predictor of the final outcome. Will the person be able to get back to work? Will he or she finish the rehab program? According to this study, the level of pain before rehab is a good way to predict the final result after rehab.

Over 3,000 patients with chronic pain from work-related musculoskeletal disorders were included in this study. The Visual Analog Scale (VAS) was used to measure pain levels. The VAS is a straight line with zero meaning ‘no pain’ at one end and 10 or ‘extreme pain’ at the other end. The patient makes a mark anywhere along the line to show the level of his or her pain.

Patients were grouped together as ‘mild,’ ‘moderate,’ or ‘severe’ according to their VAS scores. Everyone went through a rehab program of exercise, counseling, and fitness. Stress management was also included. One year later each patient was contacted by phone to assess outcomes. The authors report the following findings:

Doctors often hesitate to prescribe morphine-based painkillers for patients with chronic pain. In this review article, Dr. J. Schneider, a pain specialist, offers suggestions on when and how to use opioid analgesics.

Dr. Schneider offers physicians the following tips:

Researchers from the Centre for Spinal Surgery in Zurich, Switzerland offer doctors a review of the role and use of spinal injections. This includes discography, facet joint blocks, nerve root blocks, and epidural injections.

The authors conduct a review of studies done in these areas. They also offer their own opinions based on data from their cases. They say that studies don’t really support the use of spinal injections. The cost is far greater than the benefit patients get.

Until further studies can sort this all out, they make a few suggestions. First, discography should be used only for patients who would have surgery if they could find the exact disc that’s the problem. It shouldn’t be used just to confirm there’s a disc problem.

Second, injections into the spinal (facet) joints are best for older adults with joint osteoarthritis who don’t want to have surgery. Third, nerve root blocks should be tried before surgery for nerve root pain. In many cases the patient gets pain relief right away that last a long time.

Finally, epidural injections into the spinal canal are best used when there’s pressure on the spinal cord or on multiple nerve roots. Epidural injections don’t seem to work as well as single nerve root injections.

This review on the state-of-the-art injection methods for spinal problems gives doctors best practice guidelines. It’s based on current scientific studies and articles published.

Studies of an amputated arm and leg have shed some light on the cause or effects of complex regional pain syndrome (CRPS). This painful condition of the extremities occurs after trauma to the area. It begins after something as minor as a mosquito bite. Major trauma such as injury or surgery for joint replacement can also bring it on.

Researchers took skin samples from the donated amputations. They compared them to skin biopsies from normal human skin. The authors carefully describe their exact chemical and biologic findings for the tissue samples. Nerve fiber type and number in the skin were compared from one group to the other.

Only the samples from the amputated arm and leg showed abnormalities. There were fewer nerves and blood vessels to the affected skin. The authors think the loss of nerve fibers supports the idea that CRPS is a neuropathic (nerve-related) condition. This is because other neuropathic diseases show the same kind of changes.

The authors say they can’t be sure the changes weren’t caused by the treatment these patients received before amputation. The disease may not have caused them at all. At the very least they know that CRPS-I is a neuropathic condition whether as a cause of the disease or an effect of the treatment.

Empathy has been defined as sensing someone else’s pain or distress. In this article researchers from around the world review the effects of pain on others. Models of empathy are presented along with evidence from MRIs to support them.

For example MRI studies show there’s a link between the person suffering pain and the observer. Watching someone else in pain activates similar neurons. The observer may “feel the pain” too. This is called a mirror neuron/circuit system. The observer can be a family member, friend, health care provider, or even a stranger.

Some studies show mismatches between sufferer and observer. Sometimes the empathetic person overestimates the sufferer’s pain. Others underestimate the pain. Factors affecting how the observer feels and responds include his or her own pain in the past. It may depend on the relationship between the sufferer and observer. Empathy is higher when there is a cooperative relationship. Empathy is lower when the two people are more like competitors than friends.

The authors conclude that accurately understanding the patient’s pain or distress is important. This is the only way effective treatment is possible. If the pain is under estimated then the patient may not get the needed care. He or she becomes even more distressed. Empathizing too much may get in the way of helping.

More studies are needed to help us design the best treatment for pain. The big picture of the pain system must include how others are affected by observing pain and suffering.

In this paper researchers try to explain why treatment aimed at psychosocial factors did not have better results than usual care for low back pain (LBP) patients. Other studies have already shown there is an effect of psychosocial factors on LBP. It makes sense to think treatment aimed at those factors should be helpful. The results of their first study published earlier in 2005 were a surprise. They were certain a psychosocial approach would make a difference but it didn’t.

Taking a look at why this might be so, the scientists suggest four areas:

People who are in chronic pain need more than just help for the body. Studies have shown pain is related to patient beliefs, attitudes, and emotions. This new way to treat chronic pain is called the biopsychosocial approach. In this study a new measurement tool for pain based on psychosocial factors is reviewed. It’s called the Profile of Chronic Pain: Extended Assessment Battery or PCP:EA.

There are already many measurement tools in use to study pain. So far there isn’t one to fit all patients. This instrument was designed to be used with adults of all backgrounds from ages 25 to 80. Results considered ‘normal’ are listed by age and gender.

The PCP:EA is a series of 86 questions that can be asked over the phone or answered on paper. Many aspects of pain are included. The survey begins with a description of the pain along with location and severity. Overall health and use of medications come next. Patient beliefs about disability, control, and a medical cure are also included. A total of 20 groups of questions are asked.

The authors compared the questions and results of the PCP:EA against several other similar tests. They reviewed the methods and calculations used. This is a way to establish the validity of a new tool. Validity refers to how well a tool measures what it says it will measure.

The authors report the PCP:EA is a useful indicator of attitudes, beliefs, and social responses to pain. More study will be done to find out if the PCP:EA can predict psychosocial status six months to a year later. They will also try to see if before and after testing is sensitive to change. The authors suggest researchers and clinicians should continue to use currently available instruments until this one is fully ready.

Some low back patients with acute pain don’t get better. They become chronic pain patients. This study shows how the fear of pain more than the pain itself actually predicts who will transition from acute to chronic low back pain (LBP). And fear that is linked with pain is also linked with restricted physical movement. In the end the acute LBP patient sees himself as more disabled than he really is based on pain-related fear.

The authors came to these conclusions by studying 96 men and women with acute LBP. Each one lifted a 15- pound bag from the floor to a table. Then the bag was lifted off the table and set on the floor again. The number of times the bag was lifted and the total lifting time were recorded. The authors make note of the fact that the average adult would not have any trouble lifting 15 pounds repeatedly. But someone with back pain may feel threatened by the task.

Before starting the lifting task each person filled out several forms. The surveys asked questions about age, gender, and education level. There were questions about activity level and pain intensity. Fear of movement or reinjury was also assessed from a separate test.

If the results of this study show that pain-related fear will lead to actual disability, what can be done about it? The authors suggest two things. First, use a screening tool to identify patients with pain-related fears. Then give the patient information to reduce fear and prevent disability. The goal is to keep acute low back pain patients from becoming chronic back pain patients.

The focus of this study is worry in chronic pain patients. Do they worry the same, more, or less than people who don’t have chronic pain? Are chronic pain patients who seek treatment different from those who don’t seek treatment? And finally, does the person who worries the most have the greatest pain and disability?

The study consisted of 185 adults with chronic pain. Each one filled out a survey. Questions were asked to measure worry, problem solving, and pain intensity. Patients were also evaluated for depression, disability, and negative (catastrophic) thinking about pain.

When it comes to worry and problem solving the authors say there was no difference between chronic pain patients and others without pain. When compared with people diagnosed with anxiety, the chronic pain group had less anxiety. When compared with people diagnosed with depression, the chronic pain group was more positive. They also had better problem-solving abilities.

The results of this study support the idea that worry is a natural result of chronic pain. Seeing the many problems that could occur and thinking about possible solutions make up a large part of chronic pain patients’ worries. This process is normal.

Worry becomes more of a problem when the patient keeps looking for a cure from the pain as the only answer. The authors say this kind of focus can lead to frustration and a negative view of the person’s own ability to solve the problem of chronic pain.

How and why pain becomes a chronic problem remains a mystery. Social research has been done to pinpoint factors that contribute to this transition. In this study, researchers focus on the role of attachment anxiety on the patient’s pain experience.

Attachment anxiety describes the emotions and actions of someone who has trouble feeling comfortable with closeness in a relationship. The pattern of attachment anxiety may be high or low, secure or insecure. A person in chronic pain with insecure attachment may suffer from greater distress and depression.

In fact this study showed patients with insecure patterns of attachment also had lower pain thresholds and pain tolerance. They also had higher levels of pain intensity with compared with secure subjects.

A group of 58 healthy adults ages 21 to 69 years old were recruited for this study. Each one was tested for stress, depression, and anxiety. A separate test measured attachment styles. One final test of coping was carried out. Subjects rated how much control they thought they would have over pain. Tests were scored and each person’s type of attachment style was determined.

During the experiment each subject placed his or her entire forearm into a bath of cold water. Once the test started the amount of time in the cold bath was recorded with a stopwatch. How long after the start of the bath that the subject felt pain was also recorded.

The results showed that attachment anxiety went hand in hand with lower pain thresholds. The subject felt more pain sooner than the other people. They also found this group had more stress and depression. They didn’t see themselves as having control over pain. On the other hand the secure attachment group had fewer cases of depression. They felt they had more control over pain intensity.

One other important finding from this study was the link between age and pain intensity. It seems older, more secure adults have less pain compared to younger adults. The authors conclude by saying that the role of attachment may be a place to start when looking to prevent acute pain from progressing to chronic pain.

Doctors are using a new tool called Clinical Prediction Rules (CPRs) to help tell what a patient’s outcome might be for various problems. In this study researchers try to find CPRs for shoulder pain. Knowing what factors in patients with shoulder pain will predict the prognosis is helpful. Treatment decisions can be made with this information in mind. And patients have some idea of what to expect.

Other studies in this area found high pain intensity as the only predictor of poor outcome. Studying 587 patients with new shoulder pain was more helpful. All patients in the study received the same treatment. Data was collected on many possible factors that could affect the outcome.

Questions were asked about physical activity, workload, and psychosocial factors. Information about the patient’s age, gender, education, and lifestyle was included. Pain intensity, frequency, and duration were recorded. An exam of the shoulder was done.

The main measure of outcome was shoulder pain. Patients were contacted six weeks after treatment and again at three and six months. Persistent symptoms at six weeks were linked with psychologic complaints, repetitive movements, and neck pain. Continued pain at six months was linked with gradual onset of symptoms, high intensity of pain, and longer duration of pain at the time of the first appointment.

The authors conclude if the physician must rely on only one thing to predict the outcome of shoulder pain it would be the duration and severity of symptoms. They suggest this clinical prediction rule should be further tested before putting it into daily use.

Complex regional pain syndrome (CRPS) is properly named — it is very complex! Scientists still aren’t sure what causes it. In the last few years they have been able to divide it into two types: I and II. Drs. Jänig and Baron from the Christian-Albrechts University in Germany offer this editorial (opinion) on the topic.

After reviewing the possible mechanisms of CRPS they suggest there isn’t just one cause of CRPS but several. It’s not an inflammatory disease and it’s not a psychologic based disorder. A brief review of two articles in the February 2006 issue of the journal Pain is presented in this editorial.

Both articles are based on new and original research. Both conclude that CRPS type I is a neuropathic pain syndrome. This means nerve damage is the main cause of the condition. The editors warn readers to view these conclusions with caution.

They suggest the neuropathic pain theory is part of the big picture but there are other factors to consider. It’s more likely once the pain gets started that the neuropathic theory explains why the pain continues.

Clearly more study is needed. The editors suggest it’s too early to make a final decision based on these two studies.