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A radiofrequency ablation is a minimally invasive procedure that destroys the nerve fibers carrying pain signals to the brain. It can provide lasting relief for people with chronic pain, especially in the lower back, neck and arthritic joints. If you suffer recurrent pain and you’ve experienced good relief with a nerve block injection, you may be a candidate for a radiofrequency ablation.

What is radiofrequency ablation?

Radiofrequency ablation, also called rhizotomy, is a nonsurgical, minimally invasive procedure that uses heat to reduce or stop the transmission of pain. Radiofrequency waves ablate, or “burn,” the nerve that is causing the pain, essentially eliminating the transmission of pain signals to the brain.

This procedure is most commonly used to treat chronic pain and conditions such as arthritis of the spine (spondylosis) and sacroilitis. It is also used to treat neck, back, knee, pelvic and peripheral nerve pain. The benefits of radiofrequency ablation include: avoiding surgery, immediate pain relief, little to no recovery time, decreased need for pain medication, improved function, and a quicker return to work and other activities.

Who does the radiofrequency procedure?

The ablation procedure is usually done by a pain management doctor who has been specifically trained to perform it.

  • What are the goals of radiofrequency ablation?
  • Reduces pain for a longer duration.
  • Improves the neck, back, knee, and shoulder functions by improving the range of motion. As a result, the patient returns to work quickly, performs routine activities, and enjoys an active lifestyle.
  • Reduces consumption of pain medications.
  • Avoid or delay surgery- for example, to avoid TKR at a younger age.

Why is it called a radio frequency machine?

The frequency band of radiofrequency is similar to the frequency of radio waves; that is why it is called radiofrequency. The machine uses alternating current with an input frequency of 50Hz and produces 300,000 Hz of alternating current output. The radiofrequency lesioning process involves the passage of a very high-frequency current through a 27G thermocouple probe. The probe is passed through a 14-22G cannula, which is insulated except at the tip where the electromagnetic field generates heat and lesioning occurs.

What are the types of radiofrequency?

Conventional radiofrequency– Here thermocouple probe itself is not heated, and it dissipates heat generated at surrounding tissue. Tip temperature ranges from 65-90 degrees Celsius. Lesion generated is like the shape of a matchstick head with a diameter of 2-4mm. Size of lesion maximum around shaft and minimum around the tip, so needle placement parallel to the nerve is needed. A longer duration of pain relief is attained. Sometimes there might be faulty regeneration of nerves. The failure rate is relatively less.

Pulsed radiofrequency– High-frequency current is delivered in pulses with complete silence in between. Here we can put the needle perpendicular to the nerve as a maximum electric field is generated at the tip. The lesion is due to a strong electromagnetic field (maybe due to stimulation of analgesic chemicals), not temperature. The temperature remains at 42 degrees Celsius. It is safe as there is no nerve damage, so no deafferentation pain. The disadvantages are the high failure rate with a short duration of pain relief.

Cooled radiofrequency– Here, the tip temperature is controlled by circulating cold water through a channel in the needle at room temperature. So we can deliver more extensive power that causes the large size of the lesion. Again, we can put the needle perpendicular to the nerve or any degree.

Bipolar RF– Current flows between two electrodes instead of a ground pad. So there will be a larger size lesion. So here, one electrode produces a large, and one makes a smaller lesion.

Multichannel RF– Here, current passes through the ground pad. Both electrodes produce large size lesions.

Who performs the procedure?

The types of physicians who perform radiofrequency ablation include pain medicine, anesthesiologists, neurologists, physiatrists, radiologists and surgeons.

How can we increase the size of the radiofrequency lesion?

By using a larger gauge needle

Protruding cannula, trident cannula, venom cannula can be used

By using cooled radiofrequency, bipolar RF

By increasing time up to 150 sec

Who are the candidates of radiofrequency?

Conventional radiofrequency

Patients have trigeminal neuralgia with failed conservative treatments for Gasserian ganglion block.

Sphenopalatine ganglion block for chronic head/facial pain like trigeminal neuralgia, TMJ pain, cluster headache, CRPS

Occipital neuralgia – 3rd occipital nerve RFA

Cervical, thoracic, and lumbar facet arthropathy- RFA  of medial branches done for long term relief of pain in patients with chronic pain and conditions such as arthritis of the spine (spondylosis)

T2, T3 sympathetic nerve RFA has been done in case of pain arising from the upper and middle back, e.g., CRPS.

Splanchnic nerve RFA- Done in chronic pancreatitis pain refractory to medical management.

Lumbar sympathetic RFA has been done in patients with CRPS of the lower limb as well as for pain of ischaemic origin, e.g., Thromboangitis obliterans.

Pulsed radiofrequency

Occipital neuralgia

Suprascapular nerve RFA for adhesive capsulitis, frozen shoulder, rotator cuff tear, degenerative or inflammatory glenohumeral arthritis.

Cervical/thoracic/lumbar DRG radiofrequency is done in chronic post-surgical pain, nerve compression due to a herniated disc, or spine arthritis or spine surgery.

Intercostal nerve RFA for postherpetic neuralgia, scar neuralgia in the chest, post-thoracotomy syndrome.

Cooled radiofrequency

Lateral branches of sacroiliac joint RFA are done in chronic or refractory SI joint pain.

Genicular nerve RFA for chronic knee pain due to osteoarthritis knee

RFA of articular branches of hip and shoulder joint due to hip and shoulder arthritis

RFA of medial branches of lumbar facet joint due to facet joint arthropathy

What happens before treatment?

The doctor who will perform the procedure reviews your medical history and previous imaging studies to plan the best location for the ablation. Be prepared to ask any questions you may have at this appointment.

Patients who are take aspirin or a blood thinning medication may need to stop taking it several days before the procedure. Discuss any medications with your doctors, including the one who prescribed the medication and the doctor who will perform the injection.

The procedure is usually performed in an outpatient special procedure suite that has access to fluoroscopy. Make arrangements to have someone drive you to and from the office or outpatient center the day of the ablation.

What happens during treatment?

At the time of the procedure, you will be asked to sign consent forms, list medications you are presently taking, and if you have any allergies to medication. The brief procedure may last 15-45 minutes, followed by a recovery period.

Step 1: prepare the patient

The patient lies on an x-ray table. Local anesthetic is used to numb the treatment area. The patient experiences minimal discomfort throughout the procedure. The patient remains awake and aware during the procedure to provide feedback to the physician. A low dose sedative, such as Valium or Versed, is usually the only medication given for this procedure.

Step 2: insert the needle

The technique for nerve ablation is similar to that used for diagnostic blocks. With the aid of a fluoroscope (a special x-ray), the doctor directs a thin hollow needle into the region responsible for the pain. Fluoroscopy allows the doctor to watch the needle in real-time on the fluoroscope monitor to make sure that the needle goes to the desired location. Contrast may be injected to confirm correct needle location. Some discomfort occurs, but patients typically feel more pressure than pain.

Figure 1. A heating current is passed through an electrode to destroy the medial branch of the sensory nerve to block the transmission of pain signals.

Step 3: deliver heating current

Once the needle is in place, the patient receives a numbing medication. Then a radiofrequency current is passed through the hollow needle to create a small and precise burn, called a lesion, about the size of a cotton swab tip (Fig 1). The current destroys the portion of the nerve that transmits pain and disrupts the pain-producing signal. The burn takes approximately 90 seconds for each site, and multiple nerves can be burned at the same time.

What happens after treatment?

Most patients can walk around immediately after the procedure. After being monitored for a short time, you can usually leave the office or suite. Someone must drive you home.

Patients may experience pain from the procedure for up to 14 days, but this is generally due to the residual effects of the nerve ablation or muscle spasm. Patients are often up and around and back to work 24 to 72 hours after the procedure. Pain relief is typically experienced within 10 days, although relief may be immediate for some patients and take up to three weeks for others.

Patients should schedule a follow-up appointment with the referring or treating physician after the procedure to document the efficacy and address any concerns the patient may have for future treatments and expectations.

Where is the procedure performed? What is done during treatment?

The patient will be asked to sign consent forms as per the Indian society of study of pain format at the procedure. The procedure may take 15-45 minutes, followed by a recovery period.

The patient lies on an OT table. Then, a local anesthetic is injected to anesthetize the targeted area. The patient experiences minimal discomfort with less pain throughout the procedure. The patient should remain awake and aware during the procedure to provide valuable information during sensory and motor stimulation to increase the procedure’s efficacy.

What happens after the radiofrequency treatment?

Most patients can walk freely immediately after the procedure. Post-procedure patients are monitored for 2 hours, patients can usually resume their daily activities.

Patients may experience pain after the procedure for up to 2 weeks. It may be due to some effects of the nerve ablation or muscle spasm also can be due to a large gauge of the thick needle. Patients should schedule a follow-up appointment post-procedure after two months to document the efficacy and address any concerns regarding future treatment plans.

What are the results?

Pain relief may last from 9 months to more than 2 years. It is possible the nerve will regrow through the burned lesion that was created by radiofrequency ablation. If the nerve regrows, it is usually 6-12 months after the procedure. Radiofrequency ablation is 70-80% effective in people who have successful nerve blocks. The procedure can be repeated if needed.

What are the risks?

Radiofrequency nerve ablation is relatively safe procedure with minimal risk of complications. The complications reported in the literature include: temporary increase in nerve pain, neuritis, neuroma, localized numbness, infection, allergic reaction to medications used during the procedure, and/or lack of pain relief (in less than 30% of patients).

What are the complications of radiofrequency?

Initially discomfort due to hypo anesthesia and a neuritis-like reaction. Sometimes the pain may potentially worsen due to faulty nerve regeneration leading to allodynia.

Other rare complications such as hematoma, transitory diplopia, meningitis, Horner’s syndrome, and urinary retention may occur as written in the literature. Still, we have not observed such complications in our clinical experience.

Take home message

  • Radiofrequency ablation is a relatively safe and effective procedure for chronic pain conditions.
  • This is a daycare procedure, and the patient can go home on the same day.
  • Pain relief lasts from 9 months to more than 2 years.