A Closer Look At Acute And Chronic Pain

October 7, 2019 / Thomas Cohn, MD

Chronic pain is usually different from acute pain. Acute pain is considered to be directly related to stimulation of sensory receptors for noxious stimuli located throughout the body. It is often related to direct damage or trauma to the body. It also is the normal physiologic response to the various types of sensory receptors that is perceived as noxious or painful. Acute pain is relatively short lasting and is a direct response to direct stimulation of sensory receptors with lengths from seconds to usually less than several months. Chronic pain however is long in duration, lasting over three months and becomes independent of direct stimulation of sensory receptors for acute stimuli.

Chronic and Acute Pain

Chronic pain most often is characteristically different from acute pain. It often involves the nervous system changing on a peripheral and central basis such that sensory signals are perceived differently. In the limbs or other areas, sensory receptors become increasingly able to respond to any stimuli and then sending a signal out into the central nervous system. The nervous system essentially becomes primed for responding to sensory inputs and blasts out a powerful danger signal out of proportion to the intensity of the event. A small touch on the arm could feel like being hit by a sledgehammer.

Chronic pain is divided medically into three types;

Nociceptive
Neuropathic
Central sensitization

It can also be a combination of these. As pain becomes more chronic, the central nervous system becomes more involved and pain has more centralized components. The secondary outcomes of chronic pain over time also become prominent with increased healthcare utilization and often decreased quality of life.

There are multiple correlations in a person’s life that are associated with chronic pain. Common attributes include being female, early life trauma, family history of pain and mood disorders, genetics, sleep disturbances and mood disorders. Certain types of pain that more commonly become chronic include headaches, low back pain and fibromyalgia/diffuse myofascial pain, while the psychological factors of anxiety, depression, catastrophizing, and PTSD are linked to developing chronic pain.

Well-managed and aggressively treated chronic pain comprehensively reduces the incident of chronic pain, but as pain continues ongoing aggressive management can impact the intensity of long-term issues. It is important to treat all aspects of a painful condition. Often there are multiple factors stimulating pain and all the physical problems need to be addressed from muscles, nerves, tendons, ligaments, joints, bones and any other system involved as well as the psychological impacts.

Comprehensive management of symptoms is one of the keys to successful outcomes. Using traditional medical strategies including medications and physical therapy in conjunction with techniques like acupuncture, meditation and improving sleep hygiene may all be necessary in managing pain. Aggressive management of acute pain, especially traumatic or post-surgical, helps reduce the incident of the development of chronic symptoms.

Acute pain is a common arena for most regular physicians. Comprehensive initial management of acute painful conditions reduces the development of more chronic problems. If the pain is showing tendencies toward becoming chronic, involvement of a pain specialist can reduce the impact of the long-term symptoms.

New Technologies For Pain Management

August 19, 2019 / Thomas Cohn, MD

Medicine is evolving as electronic technology invades all aspects of medical care, and pain management is no exception. The areas that have changed the most are imaging technology and implantable devices. What is interesting to patients is how imaging can improve care and implantable devices may help when nothing else is working. The improved imaging makes diagnostic and treatment decisions easier and also makes interventions more precise when tied to management by an astute clinician. No matter how good the technology is, without the skill of a good clinician to understand the medical problem, no solution would be helpful.

The new implantable technology available is peripheral nerve stimulation. This is designed for treatment of pain that is related to damage to a peripheral nerve, such as in the arm or leg. Pain can often be traced to an isolated nerve and preventing that nerve from propagating the pain signals helps to control the problem. These pain issues arise sometimes after amputations with phantom pains, and can be seen after trauma when nerves are damaged. These problems can also occur with surgeries like joint replacements, orthopedic interventions, spinal operations and some fractures. When the pain is not resolving and an isolated set of nerves can be found and successfully blocked with local anesthetic, then nerve stimulation may be appropriate. This is a treatment to consider when simpler interventions like medications, physical therapy, and injections have not been successful.

Nerve Stimulation For Pain Management

The idea of peripheral stimulation has been around for a long time. In the distant past, traditional spinal cord stimulators were used for peripheral nerve stimulation. Unfortunately, at some point this began being abused and since those systems were extremely expensive, this process stopped. In the last two years, new systems have been designed specifically for peripheral nerve stimulation that are very technologically advanced and effective.

One example is electrode stimulation. The electrode is a very thin wire coated in silicone that can be delivered to the right place along the specific nerve with a needle guided by ultrasound imaging. The wire contains a special signal receiver that can be used to help stimulate the nerve and drown out pain signals. Most importantly, the signal generator is now a very small rechargeable unit that is placed on the skin over the end of the electrode. In the near future the electrode may connect even further from the generator such that it may be able to be carried in a pocket or other safe place.

The new technology is FDA approved for peripheral nerve pain from any type of nerve injury. The easiest insurance approval is Medicare, but other providers are starting to approve of such treatments when proven simpler treatments have failed. There currently are at least two manufacturers of equipment, the difference appears to be mainly in the generator’s ability to deliver a variety of signals that may effectively block pain signals and not be uncomfortable to the patient. From experience developed in spinal cord stimulation, the electrical signals can be varied such that the nerve pain is blocked but the patient does not feel any other odd sensations. The net effect is that one can perform activities that were once painful without the ongoing sense of pain.

For pain patients, this new technology is nice since the only thing implanted into the body is a thin wire to the appropriate location. Testing prior to implant is first by a local nerve block with a long lasting anesthetic. If that is successful, than a trial implant can be done for a week or longer to determine if a final implant would be indicated. The permanent implant is a brief outpatient procedure and can be easily removed in the future if necessary.

Pain patients who may benefit from peripheral nerve stimulators include those where pain symptoms have a definite peripheral nerve origin and the pain can be extinguished by blocking just one or possibly two nerves that are nearby each other in the body. The first problems that have been treated have been pain related to shoulder injuries that do not resolve with surgery. Other common orthopedic problems include knee and foot pain after trauma or other surgery with nerve damage or nerve pain afterwards. Amputation phantom limb pain and complex regional pain syndrome are other pain problems that may benefit from this technology. An interventional pain specialist who does implants should be able to help determine if the pain problem may be helped with such treatment. Not all pain problems can be helped and if the pain is coming from multiple pain generators or is centrally generated in the brain, this treatment is less likely to be helpful.

Could This Be The Next Big Thing In Pain Management?

June 10, 2019June 10, 2019 / Thomas Cohn, MD

Last Sunday in the science section of the newspaper there was an article about research on a new pain drug. The scientists behind the drug are convinced they have the next great drug. The skeptic in me hopes but doubts it. The reason the news has not made the traditional rounds in in all the reputable medical sites that spread news of discoveries. Furthermore, the work to date is only in animals and there has not been definite evidence this will transfer to humans.

The article discusses the work of Dr. Bruce Hammock, an entomologist at University of California-Davis. In the 1970’s he was working on an enzyme that converted a corn ear-worm to an insect. Removing the enzyme essentially killed the insect before it converted to the moth and was able to breed. Overall this was not found to be a cost effective strategy for this insect to be controlled. Since that part of his work did not pan out, he started looking for how the enzyme or related enzymes might occur in other species. especially humans.

Eventually Dr. Hammock found these compounds in humans and they supposedly reduce pain. Of note, he does not specify what these compounds are, but only says they are chemically broken down rapidly in the body naturally. He then found a way to keep them from being broken down in the body as quickly. Dr. Hammock believes this compound can somehow help relieve pain.

Believe It When We See It

The reason to be skeptic is that naturally this compound that reduces the intensity of pain is very transient in the body by the description given. This makes me believe it is likely easily broken down by chemicals in the body and is in a very limited location. This type of compound is very hard to deliver conveniently (like a pill) into the body and be absorbed. It is also likely to be easily broken down no matter what one does. Lastly, the chemical sounds like it may be something that exists in the nervous system, and thus isolated by something like the blood-brain barrier.

The researchers behind this new novel compound are just looking at starting human trials. So far there has been little funding toward the research from what has been said in the regular press. Further, as noted earlier there is no information in the extensive research pain literature on the animal-level studies discussing this compound. If the research was really promising, more money would be involved without question since pain treatment is a billion dollar industry with huge potentials.

The bottom line is that there is research going on in the field of pain medicine trying to develop new treatments and medications. However, whether any of the current research will lead to new drugs is difficult to guess. A lot of treatments have been proposed but most die as they are tested. Human studies usually take between five and 10 years to complete. Only time will tell if this research will ever lead to a new drug that is useful to treat pain.

Get Your Vitamins and Minerals From Food, Not Supplements

April 23, 2019 / Thomas Cohn, MD

Many people ask about taking dietary supplements, vitamins, minerals, and various natural compounds to improve their pain and their life. These are not officially regulated as far as how well they work. They are regulated only to the level that they cannot be toxic when ingested and they have become a billion dollar business.

Are They Effective?

Recently, a large study was done with regards to multiple dietary supplements, with an extra emphasis on medications with claims of helping with heart disease and natural degeneration caused by aging. Simply put, nothing had any positive impact on health for any of the compounds being pushed. The study was published in JAMA in January 2019 and looked at many different compounds. Included were ginkgo balboa, coenzyme Q10, coral calcium, and many others. These are all found in the vitamin and supplement aisle of many stores. None of these promoted items had any impact on cardiac health, dementia, cognition or any general component of health. Basically, none of these vitamins, compounds or minerals made a difference.

The answer of what really works is eating healthy. All these various compound are found in our fresh foods. Eating fresh food provides nutrients in a way through the gut that the appropriate vitamins and minerals are absorbed correctly and can be used by the body. In pill form or other concentrate, the body often will not be able to utilize the compound successfully. Many times the form of the compound in a pill is not absorbed or is destroyed by the body’s digestive processes. When we eat our food, our digestive system can find the nutrients and make sure they travel to the correct areas of the body. All the studies show that nutrients that come from eating a good diet are helpful, and adding a variety of supplements shows no benefit.

The best suggestion based on all these medical studies is save the money spent on supplements and spend the money on eating a healthy diet with fresh fruit and vegetables and low fat protein. Highly processed foods with high carbohydrate loads often do not have a high nutritional value. Develop a diet that comes from the outer aisles of the grocery where the fresh foods are found. None of the claims for supplements have really be proven, so save your money for now.

Low Back Pain is My Life

December 17, 2018 / Thomas Cohn, MD

I recently received an email from someone who came across my blog and was completely overwhelmed by problems with low back pain. Just like many of my patients, this problem started when they were young after a motor vehicle accident. As is often the case, every diagnostic study appears relatively normal, and one has ongoing pain in the low back region. First conservative care was performed, then injections. Most of these things had a minimal effect. Then surgery was done, nerve damage occurred and then later more surgery and a fusion. Unfortunately, pain continues despite all the efforts to take care of possible changes in the spine.

This is unfortunately a typical story I have heard from countless patients in my practice. The one thing no one can do is go back in time and change history. Once surgery is has been done, it cannot be reversed and permanent changes usually result.

The Brain and Pain

Pain is the brain’s interpretation of sensory signals it is receiving. Furthermore, it perceives both sensory signals and emotional aspects of pain. The signals are also coming from multiple structures in the low back region including multiple joints, nerves, discs, bones, tendons, ligaments, and muscles at the very minimum. We have no way to test most of these structures to see if they are sending sensory signals. The brain is usually left guessing where the signals are coming from and if multiple structures are sending sensory outputs, the brain can only manage one or two of them and then ignores the others. Eliminate one source and another signal that once was being ignored now becomes perceived. Thus pain is a complex symptom of system overwhelmed with noxious sensory signals.

Naturally the body is meant to adapt to a certain amount of change that is constantly occurring within it. Once an injury happens, hopefully mechanisms within the body will allow it to heal. Sometimes just a slight mechanical difference in the body is the source of ongoing sensory signals. These signals can be perceived as pain. Unfortunately, pain also is an emotional experience, and therefore it can become very distressing.

Realizing that pain has both sensory and emotional qualities is very important. If the perceived sensations are indicating a physical problem in the body that needs to be corrected to prevent loss of body function, then an intervention, like surgery that is not reversible, may need to be performed. If there is no permanent damage being done to the body but pain is occurring, the most important intervention is make sure you are not changing mechanically or physically any structure that absolutely does not need to be altered. Once surgery is done, there are often permanent consequences and the cure may be worse than the original problem. Before considering any surgery, ask yourself if the pain gets worse and my functional abilities are less, can I live with that, or can I adapt to what I have and find a way to move forward?

Pain Care Isn’t Simple

Whenever someone does have pain, there often is not a simple answer why and not a simple solution to cure the symptoms. Once you change the body with surgery, the change is permanent and there may be constant sensory signals being produced and perceived as pain. The goal in treatment of any patient with pain is to manage all the possible sources sending abnormal sensory signals and to normalize the brain’s perception and management of the signals. Ideally one can make the situation where the signals do not interfere in life. For those who have ongoing pain, the goal is changed to manage the perception of pain. There is not yet a way to regenerate nerves, muscles and disc reliably with new technology. Stem cells in the body can only do limited things currently as well as other regenerative technologies. The research is showing some limited results in only certain situations. Medicine may improve the results of treating certain conditions, but once we have changed the body permanently by surgery or significant degeneration, we are not miraculously going to change it back to a youthful status.

Good pain management and physical medicine focuses on improving function, ability, strength, endurance, flexibility and perception of pain. It is often more important to deal with emotional aspect of pain and its perception than to try to eliminate some sort of physical change seen in the body. Retraining the body to maximize its ability despite having abnormal sensations is often the solution versus doing excessive medications, interventions and chasing elusive cures. The brain and its perception of the body as well as its emotional wellbeing may be the most important aspect of treating the pain. Chronic pain may not have a medical solution, but maximizing functional and emotional abilities goes a long way towards a more normal life.