Overview of Radiofrequency Ablation
Since the 1950s, doctors have used electrical currents to create controlled changes in body tissues. This technique didn’t start being used for severe, unmanageable pain until the 1970s. The basic idea involves sending radiofrequency, which is a type of electrical energy, through a small device placed near the pathway in the body responsible for the feeling of pain. This disrupts the signals that cause the sensation of pain. The heat from this process creates a predictable zone where the tissue is destroyed, and this is aimed directly at the nerves that transmit or regulate the sensation of pain.
Today, there are several ways to apply this heat-based technique, all of which rely on the same basic idea. These methods include pulsed radiofrequency ablation (PRF), which uses short bursts of energy, water-cooled radiofrequency ablation (WCRF), where the device is cooled with water to allow applying more energy without overheating, and cryoneurolysis (CN), which uses extreme cold to numb the nerves.
Anatomy and Physiology of Radiofrequency Ablation
Thermal energy, or heat, is often used in medical treatments for chronic pain in the back and neck. It’s directed close to or directly onto the nerves that are causing the pain, which originate from the spinal cord. This method has been successful in treating pain that stems from facet joints in the spine by aiming the heat at a specific nerve called the dorsal ramus.
Thermal energy treatment has also been effective for discogenic back pain, a condition where damaged discs in your spine cause pain. Here, the treatment targets the ramus communicans – another specific nerve associated with this kind of pain. This treatment approach can also focus on a group of nerve cells, known as the dorsal root ganglia, to help with radicular back pain which is sharp and electric shock-like pain that travels down your leg. Another target can be the lateral branch nerves for issues related to the sacroiliac joint, which is located in your lower back and connects your sacrum – the bottom of your spine, with your iliac bones – the two large bones that make up your pelvis.
While it’s less common, thermal energy treatment has also shown promise in treating facial pain, chest pain, and pain in the front and back of the pelvic region.
Why do People Need Radiofrequency Ablation
A study exploring the use of heat, or thermal lesioning, to manage pain concluded that heat levels produced by temperatures of 40 degrees and 67 degrees Celsius didn’t significantly affect clinical outcomes. This resulted in a shift in thinking towards the idea that electricity, not just heat, might be responsible for the beneficial effects seen in pain management. This insight led to the introduction of a technique known as pulsed radiofrequency (PRF), which uses intermittent electrical current to minimize thermal tissue damage.
Even though lab tests suggested that PRF could cause stress and damage to nerve cells, later findings suggested that the temperature-measuring tools may not be reliable enough to rule out brief heat spikes, hence downsizing the role of electricity in causing tissue damage.
As of now, we don’t have concrete proof suggesting that high-frequency electric currents alone can help disrupt pain pathways. The general understanding is that a combination of heat and electricity contributes to the beneficial effects seen in pain management. Having said that, PRF has been utilized in treating various types of pains located at different areas of the body, such as radicular pain, facetogenic pain, post-herpetic neuralgia, post-amputation pain, and post inguinal herniorrhaphy pain, to name a few. This treatment approach has been applied to various nerves as well as even for conditions like premature ejaculation and pancreatic pain.
Water-cooled radiofrequency (WCRF) ablation is another technique used for managing pain. Similar to conventional RF, WCRF uses a continuously flowing water to cool-down a multi-channel electrode. This cooling action then allows the flow of radiofrequency current to create a larger region of heat damage without overheating the electrode itself. This method creates layers of varying heat around the probe, starting from the coolest area closest to the probe to gradually hotter areas farther away. The size of the heat damage is also dependent on factors such as the size of the probe, the temperature of the electrode, the duration of the current, and the presence of heat sinks including blood flow and spinal fluid flow. WCRF is primarily used for pain sources with variable and multiple innervation. Currently, WCRF has two versions, monopolar and bipolar, each used for specific joint dysfunctions and discogenic pains.
Cryoablation, a process involving freezing nerve cells, is another alternative for managing pain. Unlike some traditional methods, cryoablation does not produce neuromas or hyperalgesia, conditions that can increase sensitivity to pain. It works by damaging the blood vessels of nerves which can lead to the destruction of nerve fibers. Nerves regenerate slowly through their supporting tissues and the time taken for pain relief could range from weeks to months. Cryoablation has been used for a variety of pain conditions ranging from thoracotomy pain to facial and spinal pains, abdominal and perineal pain syndromes. The use of Cryoablation seems to be limited only by the skillset of the person performing the procedure.
When a Person Should Avoid Radiofrequency Ablation
Radiofrequency ablation, a procedure that uses heat to reduce or stop pain, can’t be used in some situations. These include if a patient says they do not want it, if the pressure in their brain is too high, or if they have a local infection. Because this treatment is often close to the backbone, doctors need to take special care if the patient is using any medications that thin the blood or if they have any conditions that increase the risk of bleeding.
Doctors usually follow guidelines set by the American Society of Regional Anesthesia and Pain Medicine. These guidelines suggest when to stop using certain blood-thinning medications: aspirin for prevention (6 days before the procedure), clopidogrel (7 days), apixaban (3-5 days), rivaroxaban (3 days), warfarin (5 days), and intravenous heparin (4 hours). It’s also necessary for doctors to review any blood clotting tests before the treatment.
Other situations where radiofrequency ablation might not be suitable include cases of bacteremia, an infection in the bloodstream, or in situations where the body’s structure is unusual due to birth or surgery. Since these procedures are elective, meaning they’re not emergencies, it’s crucial to carefully consider the risks and benefits. Doctors must also ensure the patient fully understands and agrees with the plan.
Equipment used for Radiofrequency Ablation
For any medical procedure, certain things are necessary. These include a roomy area that can fit all the required tools and staff members. Big items that are needed are a special table or bed for the patient to lie on, which helps avoid injuries related to their position, a machine that can take X-ray like images (known as fluoroscopic imaging equipment), and a clean table for the surgical tools.
Monitors are also needed to check on the patient’s level of oxygen, their breathing, blood flow, and temperature; this is especially important if the patient needs to be sedated. If the sedation needed is deep or if the patient is to be put completely to sleep (also known as general anesthesia), there must be a certified anesthesia provider on hand.
Specific tools needed for the procedure include special needles, tubes with small electrodes attached, and a unit that allows these tools to communicate or interface with other equipment. In case of emergencies, it’s important that items like extra oxygen, a suction machine, and an emergency response cart (also known as a code cart) are accessible and easy to get to.
Who is needed to perform Radiofrequency Ablation?
The method of using heat to treat nerve pain, known as thermal nerve ablative techniques, should only be carried out by highly experienced medical experts who specialize in doing procedures on the spine with the help of a special x-ray machine called a fluoroscope. These specialists are usually doctors who have additional qualifications and training in pain management. They could have backgrounds in different medical fields like anesthesiology (related to managing pain and putting patients to sleep during surgeries), physical medicine and rehabilitation (helping patients regain body functions after disease or injury), family medicine, neurology (study of nervous system), emergency medicine, and psychiatry (mental health).
Like most medical procedures, there are other healthcare professionals who assist during this treatment. For example, a circulating nurse helps with the necessary equipment and provides support to the patient. Additionally, a radiology technician, who is trained in taking and interpreting medical images, helps with tasks related to radiographic imaging (taking pictures of the inside of your body).
How is Radiofrequency Ablation performed
Here’s a simplified explanation of how we approach certain kinds of medical treatments involving heat, cool, and electricity to manage pain. These treatments are often used when pain is coming from multiple sources, and they’re guided by special x-ray.
One method uses an electrode, which is an electrical conductor, that’s placed near the pathway where the pain is coming from. This technique generates heat from electrical currents which warms up the tissue around the electrode. Interestingly enough, the electrode isn’t heated directly but gets warm due to the warmth of the tissue around it. During this procedure, the heat is carefully controlled and cycled on and off to maintain the desired temperature in the tissue. Above 45 degrees Celsius (about 113 degrees Fahrenheit), nerve tissue begins to deteriorate. But it’s critical not to exceed 80 to 90 degrees Celsius (176 to 194 degrees Fahrenheit) as that could cause gases to form in the tissue.
While earlier studies suggested that only certain types of nerves were affected by the treatment at particular temperatures, newer data suggests that all nerve types are impacted by the therapy. To avoid injures to sensory and motor nerves, the use of high-temperature therapy has generally been limited to a certain type of procedure. Often, a range of 55 and 70 degrees Celsius (131 to 158 degrees Fahrenheit) is used for a specific type of nerve damage.
There are also two different techniques used in water-cooled radiofrequency therapy. For one type of joint dysfunction, a small electrode is used to apply heat for a short amount of time. Due to this technique causing a large area of tissue damage, the electrode is placed a fair distance from the nerve. For disk pain, a different version of this technique is used. In this case, two small introducers are used with the temperature raised over a period of time.
Cooling techniques have also been used to relieve pain since ancient times. But for them to have lasting effects, a specific low temperature (-20 degrees Celsius or -4 degrees Fahrenheit) has to be reached. The cooling effect is not only dependent on the temperature but also on how long the cooling took place, the size of the cooling probe, the proximity of the probe to the target nerve, and how many cycles of freezing were applied.
Modern cooling systems utilize a double-lumen aluminum tube, which is connected to a gas source. The target temperature is generally between -50 and -70 degrees Celsius (-58 to -94 degrees Fahrenheit). The gas circulates in a loop and forms an ice ball at the tip of the probe. The ice ball’s size will depend on the size of the probe used.
A special kind of needle is usually utilized to position the cooling probe and protect the skin from its freezing temperature. Moreover, most cooling probes come with a built-in nerve stimulator that allows nerves to be tested both for sensation and muscle contraction. Additionally, the gas supply has to be carefully regulated. Under-supply of gas may render the procedure ineffective, while on the other hand, too much gas may cause unnecessary freezing damage. Finally, before removing the cooling probe, the ice ball must be thawed to prevent any local tissue damage or nerve pulling.
Possible Complications of Radiofrequency Ablation
When heat is used to treat certain medical conditions, there can be some negative side effects. These include bleeding, infection, damage to the nerves caused by the needle used during the treatment, misplacements, and even burns from improperly placed grounding pads. The most commonly observed side effect is discomfort following the treatment, but luckily, it usually goes away after a short while.
One specific type of treatment known as ‘cryoneurolysis’ which freezes the nerves to relieve pain, can also lead to the formation of a neuroma, a kind of nerve tumor. Although it hardly occurs, when it does, it can cause neuropathic pain, a type of pain related to nerve damage or a malfunctioning nervous system. Other side effects when this treatment is used near the face include hair loss and changes in skin color.
Thankfully, serious side effects and complications from heat-based treatments are extremely uncommon. The risk of these happening can be greatly reduced when the procedure is done correctly, guided by images like x-rays, in a sterile environment, by following the right pre-procedure checklists, and also greatly depends on the skill of the practitioner performing the procedure.
What Else Should I Know About Radiofrequency Ablation?
Managing chronic pain is a very complex process because so many different factors can contribute to it. This means that treating it isn’t a one-size-fits-all process but involves a range of solutions including medication, physical therapies, and different medical procedures. However, health professionals are keen to decrease the use of narcotics or painkillers to treat chronic pain, to avoid patients becoming dependent on them.
So, one increasingly important option is using interventional techniques – that’s medical treatments performed by directly targeting the areas of the body causing pain. One of these is called radiofrequency ablation (RFA), which involves using heat generated from medium frequency alternating current to reduce pain. It’s been shown to help reduce pain and reliance on medication when used correctly.
One specific type of RFA, pulsed radiofrequency (PRF), has been shown to be effective in certain cases. It’s been used a lot to treat neck and lower back pain, and there are reports of it being used to treat other conditions, too, such as facial pain and shoulder pain. However, at this time, the benefits of PRF appear to be fairly short-term and we need larger studies to clearly see just how effective it is for different conditions.
Water-cooled radiofrequency ablation (WCRF) is a similar procedure that’s been shown to benefit people with a condition affecting their back and hip area (sacroiliac joint disease). However, at this time, there’s not much research data on this procedure.
Cryoablation, which is a process where extreme cold is used to destroy diseased tissue, is another technique. It’s been used mainly to manage pain following chest surgery, with most of the studies conducted back in the 1980s. However, newer research has shown similar pain control to an existing technique for administering pain relief into the space around the spinal cord (thoracic epidural). But, it’s not currently recommended because it was seen to increase the incidence of nerve pain. Cryoablation has also been used for head, face and neck pain, with mixed success. In patients who had hernia surgery, only one study showed cryoablation led to less use of painkillers.
In general, combating chronic pain is an ongoing medical challenge and it requires a combination of treatments. Among them, radiofrequency ablation therapies can potentially offer short-term relief without making patients too reliant on medications.
