Stimulating the nerves to treat chronic pain

MALAYSIA – The good news is, as a generation, we are living longer and healthier. We can afford to eat healthily and live more balanced lifestyles than our forefathers, who had to work tirelessly.

But with advancements in health also come other diseases previously not experienced; in particular, pain related to ageing and age-related conditions, nerve pain from more modern operations, and cancer treatment.

This sort of chronic pain, which has been recognised as a disease in its own right by the World Health Organisation, is very different from acute pain, which serves either as a warning sign or for adaptive purposes while the body heals itself from damage.

Chronic pain serves no purpose and is now seen as a long-term condition exactly like diabetes or high blood pressure.

It is mainly a diagnosis of exclusion, made after appropriate investigations have ruled out sinister pathology. It is best dealt with in a pain management setting by a pain specialist.

It is a disease that has lifestyle ramifications and is managed by a multitude of combination treatments. There treatments aim not to cure, but instead, to help maintain a good quality of life and function.

Chronic pain can destroy lives, and is a major clinical, social and economic problem.

But above all, persistent pain is a human tragedy.

Treatment options

While quality specialist pain management is available, it is in short supply.

In Malaysia, we are light-years away from giving chronic pain the priority it deserves. Indeed, even in the western world, they are only just starting to invest the funds needed for research into newer treatment options.

In the past, managing pain was by treating it as a symptom, i.e. the patient was subjected to many possible investigations and surgical options.

For example, cervical spondylosis – a degenerative joint condition causing headache and neck pain – would be treated with a spinal fusion or decompression.

Fusing of the spine is used primarily to eliminate the pain caused by abnormal motion of the vertebrae by immobilizing the degenerated vertebrae themselves. However, spinal fusion is also the preferred way to treat most spinal deformities, specifically, scoliosis and kyphosis.

Currently, investigations are targeted at excluding “red flags”, i.e. impending nerve damage (cord compression), cancer and spinal cord myelopathy (progressive loss of the proteins covering the spinal cord).

These can be managed symptomatically via certain surgical techniques like a laminectomy, where a portion of the vertebral bone called the lamina is removed.

Failing that, there are various strong medications that can be prescribed to ease the pain.

However, these can, on occasion, lead to tolerance (i.e. needing larger doses), dependence and addiction (particularly with opioids), and intolerable side effects, like fatigue, sleepiness, upset stomaches, and nausea and vomiting.

Pain specialists are always on the lookout for newer treatments with minimal side effects.

One particular treatment that has emerged in recent years is Percutaneous Electrical Nerve Stimulation (PENS).

In the past, acupuncture (western dry needling) and TENS (Transcutaneous Electrical Nerve Stimulation) have been used to effectively treat various forms of arthritic pain.

However, the effects are very transient, and symptoms recur within less than a week.

Top-up treatments have to be given every few weeks in order to regain the benefits.

PENS, TENS and acupuncture

In chronic pain, the affected nerves and muscles are hypersensitive and send incorrect electrical impulses.

The nerves “misbehave” by sending off random electrical messages, which cumulatively gives rise to the sensation of pain, along with causing shortened, tense muscles. (See graphic)

The hypersensitive spot will eventually also affect the surrounding area, causing the sensation of pain to further spread.

This can be readily diagnosed by the bedside, or in the outpatient department, via an ultrasound scan.

PENS is similar in concept to TENS, but instead of placing electrodes on the skin of the affected area, needles are inserted, either around or immediately adjacent to the nerves serving the painful area.

The nerves are then stimulated by passing a low-voltage electrical current through the needles.

PENS is generally reserved for patients who fail to get pain relief from TENS.

PENS differs from electrical acupuncture in that the placement of needles for electrical acupuncture is based on traditional Chinese medicine theories regarding the flow of energy or qi through the body.

In PENS, the needles are located based on the area of pain.

Basically, PENS combines the benefits of acupuncture and TENS.

Becoming less sensitive

The PENS therapy causes a tingling sensation (paraesthesia) in the area of the body associated with the pain. It alters the activity of the peripheral nerve, and reduces and controls the sensation of pain.

The treatment does not destroy the affected nerves, but makes them less sensitive to pain.

A low-voltage electrical current is delivered to the fatty layer just below the surface of the skin close to either a specific nerve, or to all the nerve endings situated in that area.

PENS therapy is used to treat chronic nerve pain, including areas of hypersensitivity, headache and chronic post-surgical pain.

Occasionally, PENS is used as a diagnostic tool.

Even when it does not produce a pain-relieving effect, it can help the pain team find an alternative treatment.

There has been extensive research done on this treatment, and in April, the United Kingdom included it in the National Institute of Clinical Excellence guidelines as part of the treatment for chronic pain.

It is useful in all forms of chronic pain, including non-specific low back pain, occipital headache, post-surgical pain, post-hernia repair and cancer-related pain (from either surgery or radiotherapy).

Its advantages are that it is minimally invasive, avoids the risks and expenses of surgery, and is well tolerated.

Although many more innovative technological treatment options for pain are available, PENS has so far been the most rigorously tested, and a good evidence base has emerged, both with clinical trials and amongst peer reviews and physician use.

Malaysia is the first country to introduce this treatment in South-East Asia.

It should be noted though, that PENS is not meant to be used as a single treatment option, but as part of a wider pain management programme encompassing targeted physiotherapy, medicine optimisation, minimally-invasive injections, and surgery, if indicated.

Dr Maya Nagaratnam is a pain specialist, pioneering PENS therapy in Malaysia, and also a British Medical Acupuncture Society-certified acupuncturist. For more information, e-mail starhealth@thestar.com.my. The information provided is for educational purposes only and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.

Source: The Star

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