Low back pain is a debilitating condition that affects 80% of the population at some point in their lives. If you have suffered from low back pain for more than a few weeks, your doctor might refer you to physical therapy. Your physical therapist will come up with a treatment program to try and get you back to regular functioning as soon as possible, using a variety of tools and techniques. Some of these tools may include treatments such as electrical stimulation. That can sound quite scary and conjure up images such as shock therapy that was used on patients in asylums, but fortunately this technology is nothing like that.
Modern methods in physical therapy can make use of a few different types of electrical stimulation that can help to decrease pain and inflammation, help your muscles to contract properly, and improve your circulation. Your physical therapist will do a thorough assessment of the issues specific to your condition, and should discuss the types of improvements and responses that they expect to see when using one type of treatment over another. If you don’t understand completely, don’t be afraid to ask more questions, it is important to feel that you are getting the most appropriate treatment for your specific condition.
Knowing The Difference Between Types of Treatments
The different types of electrical stimulation techniques can be confusing, especially when trying to decide on one type over another. So we put together this article to help you understand the differences between the types of electrical stimulation, and to see the research behind the effectiveness of each type. This will hopefully give you some understanding into why your physical therapist will recommend one treatment over another.
This article can also be used for those who are trying some of the new at-home treatments that are available in the marketplace. There are many electrical stimulation devices that can be purchased without a prescription from your doctor. While it is always best to speak to your healthcare provider before trying a new treatment, hopefully this article will help you understand which device might be the best fit for your situation, as well as understanding the risks and benefits associated with each one. The types of electrical stimulation devices that we are going to cover are: TENS, Russian Current (FES), and NEMS.
What Is A TENS UNIT?
Transcutaneous electrical nerve stimulation (TENS) works by interrupting the pain signals that travel from injured muscles and tissues to your brain. The TENS unit is a small, battery-operated device with electrodes that you place over the painful area on your body, and it sends electrical impulses through your body to alter/interrupt the pain signals heading to your brain. TENS stimulates the sensory nerves and suppresses the pain signals that are being sent to the brain, basically tricking the brain into ignoring the pain for a short time.
How Does TENS Work?
A TENS (transcutaneous electrical nerve stimulation) unit is a small, battery-operated device that can help with pain management. The device has leads attached to adhesive pads called electrodes. The electrodes are placed on the skin near the painful area. It delivers mild electrical impulses that can be adjusted in frequency and intensity to help modify pain signals in your body.
Typically treatment sessions last between 15-40 minutes and a slight tingling/warm feeling can be felt. The frequency and intensity of the signals can depend on the type of unit you have, some use low frequency, while others use high frequency signals. Users can adjust the frequency and intensity as necessary so that it is not causing additional pain and so that it is well tolerated.
In clinical studies it appears that low frequency TENS is generally better for chronic pain since it inhibits descending pain transmission, while high-frequency TENS is often used in treating acute pain since it works on stimulating A-beta fibers.
Does TENS work?
In one study, 90 patients were assigned low frequency, high-frequency, or placebo TENS and used it for 45 minutes twice a day for 32 weeks. The results of the study showed that the high-frequency TENS had the best effect on pain reduction over the 6 week period. The low-frequency TENS showed the best long-term results at 32 weeks, as well as improving functioning.
Other studies have found that both high- and low-frequency TENS were able to significantly reduce post-operative pain.
The International Association for the Study of Pain (IASP) describes conventional TENS as “high-frequency” “low-intensity”. The intention of TENS is to generate a strong, comfortable, non-painful, pain-relieving effect on the affected area. Using a higher amplitude can activate a different type of effect that can actually cause more pain in the affected area. This is not the desired outcome for TENS. High frequencies and high intensities that are just tolerable to the patient are sometimes used, but only for very short periods of time. Intense TENS can be useful for pain relief during minor medical procedures like removing stitches or dressing wounds.
TENS does not address the underlying causes of low back pain and therefore it is not something that can fix or cure low back pain. It is a treatment that can temporarily ease the pain while it is being used, not something that heals conditions.
A study was conducted of 47 dental professionals who received a single session of either high-frequency TENS or placebo to see the effects of TENS. The researchers found that the pain relieving effects of TENS was maintained for 3 hours after its application, but it did not last until the following day. Another study found that the duration of pain relief after stopping using the TENS device lasted anywhere from 30 mins to 2 hours.
TENS And Tolerance Build Up
The effects of TENS are rapid pain relief, but also rapid return to pain once the device is no longer being used. It is also important to note that long-term use of TENS therapy may lead to a tolerance-build up. In other words, the effects decline over time, either because the body is used to the TENS stimulation impulses or because the condition has not improved. This is why it is important to use TENS in conjunction with other rehabilitative therapies, and not use it as a stand alone treatment. The underlying cause of the pain needs to be addressed.
Some researchers believe that switching up the intensity of the frequencies can help to delay this tolerance build-up. It does seem as if, by day 10, even alternating frequencies became ineffective, though, so this may not be helpful for long term use.
Another consideration involves the age of the patient. A group of patients was divided by age and it was discovered that for younger patients there was a significant decrease in pain with both high and low frequency TENS. In the older patients, only low frequency TENS increased the pain thresholds. The study concluded that TENS is effective in young, but not older individuals.
With pain being such a subjective experience, it makes sense that different populations would experience treatments in unique ways. The researchers suggested that “further studies should be conducted to confirm these results in pain populations, and to identify strategies that could enhance the effect of TENS in the elderly.”
Russian Stimulation/ FES
What Is Russian Stimulation?
Russian stimulation is another form of electrical stimulation. It uses high-frequency electric waves to contract the muscle tissue. If your muscles are injured or if you have had surgery that has affected your muscles, your muscles might be weak and unable to contract strongly on their own. Physical therapists use Russian stimulation (sometimes known as Functional Electric Stimulation) to forcefully contract the affected muscle. Russian stimulation is non-invasive and is an effective way to restore (or preserve) muscle strength.
How Does FES Work?
Russian stimulation is a medium frequency that is often used to help with the recovery of athletic injuries such as ACL (anterior cruciate ligament) tears. It helps athletes improve their strength. FES is also used to treat nerve damage from conditions such as MS (multiple sclerosis) - especially with a condition known as “foot drop”. In MS the muscle no longer receives correct messages from the central nervous system, so the FES provides the signal to help make the muscle move.
The goal of FES is to combine the electrical device with the activity and movement so that the weak or paralyzed muscles can repair and recover themselves - in other words, it addresses the underlying cause of the condition. It is not used as much for pain relief as it is used for muscle rehabilitation although when paired with activity studies have shown that when pain was measured, using a Visual Analogue Scale (VAS), the group that used the Russian current technology showed sustained pain relief one month later at follow up, whereas the control group did not show that level of pain relief.
What Is FES Used For?
There are numerous documented benefits on using FES for weak muscles. Some of these include:
Increase in blood flow
Increase bone density
Increase muscle bulk
Promote nervous system recovery within the spinal cord.
FES devices are typically small and are worn constantly while someone is moving. They are battery powered and convenient to use. They are also very expensive. These devices fall into the $5,000 - $6,000 range and are not typically covered by health insurance.
What Is NMES?
Neuromuscular electrical stimulation (NMES) is used by physical therapists in a similar way to Russian stimulation. Primarily used for rehabilitation after injury, stroke, or accidents, NMES uses an electrical current to cause the muscles to contract. During the treatment, the therapist places electrodes on the skin directly over the targeted muscles. The NMES unit passes safe electrical impulses through the area, stimulating and contracting the muscles. This stimulation helps to restore the communication between the brain and the muscle to help retrain the muscles to work normally again. This type of therapy addresses the underlying cause of the condition.
What Is NMES Used For?
NMES is often used to increase blood circulation, relax muscles spasms, prevent atrophy of the muscles, re-train the muscles, and increase range of motion. It is basically the same as EMS (Electrical Muscle Stimulation) but it is more focused on rehabilitation in a therapeutic setting than on training for athletic performance. Its goal is often to help patients return to normal function quickly after surgery or an injury.
Unlike TENS units, NMES is used to provide long term relief for low back pain. In the case of NMES, electrical impulses are sent to the motor nerves, not the sensory ones used for TENS units. The impulses contract and relax your muscles, helping to strengthen and stabilize them. NMES also improves blood flow to the low back and promotes tissue healing. The relief that is then experienced is more long term than temporary pain relief.
Does NMES Work For Low Back Pain?
Sadly there is not a lot of clinical research that examines the benefits of NMES in treating low back pain, specifically. A meta analysis of data showed that there is “moderate to strong evidence that NMES is effective for some problems post-stroke, for weakness post-ACL repair and total knee replacement, for muscle weakness in knee OA, and for debilitation and weakness after critical illness.” There are clinical trials currently underway to examine the effectiveness of NMES in treating low back pain but we are still waiting for those results to be published.
What Is EMS?
Electrical muscle stimulation (EMS) works in a similar way to a TENS machine in that it transmits electrical impulses through electrodes that are attached to the skin. Unlike TENS, these electrodes are applied to key muscle groups such as the quadriceps to help contract them (a bit like NMES). The electrical signals trigger contractions of the muscles, which can be either short and frequent, or long and sustained, similar to how people normally train muscles when they are strength training.
What Is EMS Used For?
EMS is often used in physical therapy and rehabilitation clinics as well as fitness centers. You can also find EMS devices that are available for personal use at home. EMS is used to strengthen the muscles, increase muscle size, improve muscle endurance and accelerate recovery. It is a great way for athletes to help recover injured or strained muscles.
EMS uses a stronger electrical current than TENS and is not designed to treat pain. EMS is beneficial for those recovering from surgery, or to improve muscle contractions while working out.
Does EMS Work For Low Back Pain?
A meta-analysis of EMS therapy looked at 38 different studies with a total of almost 1200 participants. They found that EMS significantly reduced chronic musculoskeletal pain and stated that it is an effective treatment modality.
Fortunately, or unfortunately, depending on how you look at things, what you pay for is what you get. If you are thinking of purchasing an EMS machine, you must make sure that it is FDA approved and that it is high quality. Gadgets acting on human muscles have been around for many years. Infomercials promising insane abs without going to the gym or the perfect glutes without any working out ran rampant. People were quickly disappointed when they began to realize that it is impossible to get the perfect body without real work in terms of working out and eating properly.
The types of EMS units that have produced results in clinical trials are clinical grade and these are the sorts of units that pro athletes use for rehabilitation or during complex training. The device should have varying intensities of stimulation. A unit like this will cost anywhere from $200 to $1000.00 and regular use is required, preferably from a trained administrator. Sadly many gadgets will talk about using EMS for pain relief which has not been proved in any clinical trials due to its nature. Some pain relief may possibly be experienced if the muscles relax sufficiently, but this is anecdotal and has no data to support it.
With so many different products on the market, and some very confusing acronyms to go with them, it can be hard for consumers to know which products to try. If you suffer from chronic low back pain there is a good chance you have tried tons of different products, experienced some relief for a while, and then ended up right back where you started. Or maybe the only thing that really works for you is medication but you are scared of what that could do to your body over time so you want to find something different.
As you can see, each of these types of electrical stimulation works very differently, and they have very different purposes. It is always a good idea to chat with your doctor before trying a new treatment and they can help you consider any potential concerns, such as if you are pregnant, use a pacemaker, or have epilepsy. Some of these products can work as a temporary add on to traditional remedies such as exercise. You can also check out our blog on New Technologies in Back Pain Treatment as we review some other types of treatments, such as SEMG (surface electromyography), that are being used with good outcomes in treating low back pain. We hope that you found the information in this blog useful, and that it can help you make a more informed choice when it comes to trying out new treatments.