Radio Frequency Ablation
Advance Radiofrequency machine – available at CHEERS-Interventional Pain Management.
Radiofrequency is latest, safest & very effective method available to deal with many chronic pain conditions
Radiofrequency (RF) is a neurolytic techniques that uses heat to produce controlled tissue destruction (thermocoagulation) and thus reduce pain by modulating pain transmission, without causing clinical signs of nerve damage. Pain relief can last for long period before the procedure has to repeated.
RF is classified as a percutaneous minimal invasive procedure for patients whose pain does not respond to appropriate medical and physical therapy. During the procedure, an insulated needle is placed in the vicinity of the nerve to be lesioned. The needle position is checked, typically using multiple fluoroscopic X-ray views and by testing motor and sensory nerve stimulation. Once the correct position has been established, a grounded electrode is passed through the insulated needle to the tip. A current is then passed through the electrode, which heats up the surrounding tissue (because of the resistance produced by the body) and causes a lesion around the tip. There are two types of RF currently in use.
- Continuous RF uses a constant output of high-frequency electric current to produce temperatures of 45C or more (the temperature at which permanent nerve damage occurs), resulting in neuroablative thermocoagulation.
- A more recent technique, pulsed RF (PRF), utilized brief “pulses” of high-voltage, RF-range (300 kHz) electric current to produce the same voltage fluctuations in the region of treatment that occur during conventional RF treatment, but without heating to a degree at which tissue coagulates. The heat generated is instead dissipated between pulses. PRF produces a transient inhibition of evoked synaptic activity and continuous RF produces a lasting inhibition.
Both continuous RF and PRF treatment induce distance-dependent tissue destruction under the stimulating needle, but the effect is more pronounced with continuous RF. On the other hand the findings suggest that the acute effects of PRF are more reversible and less neurodestructive in nature than the classic continuous RF mode, even in normothermal conditions.
MODE OF ACTION OF RF The mode of action of RF has not yet been elucidated following are probable mechanisms –
- Thermocoagulation of nerve fibers (which denatures the nerves),
- Electric field created by RF current induces changes in the nerve cells and has a neuromodulatory effect on pain processing mechanisms at the dorsal root ganglion, dorsal horn, and molecular levels by changing gene expression in pain-processing neurons.
- PRF produces prolonged analgesia by inhibiting excitatory C-fibers via long-term depression thereby delaying pain signal transmission towards spinal cord.
- Trigeminal neuralgia (TGN) – RF lesioning of V1, V2, or V3 is an excellent choice for pain relief in TGN. It is day care, very minimally invasive, less costly & very safe method as compare to surgical decompression.
- Headache – Many headaches are caused by upper cervical pathologies like facet joint pain syndrome, C1C2 neuralgias, & Greater occipital neuralgia. These conditions can be diagnosed by specific fluoroscopic guided diagnostic nerve block. If pain relief is significant RF is applied to give long term pain relief in this group of headache patients.
- Chronic Neck Pain – Patients with chronic facet joint pain syndrome are treated with RF lesioning of medical branches of dorsal root. This is the only treatment available to deal with pain originating from facet joint. It gives very dramatic relief in pain in most cases. Many intradiscal RF treatments are available to deal with herniated disc related pain in neck & lower back
- Chronic low back pain – same as in chronic neck pain
- Facial pain syndromes – Stellate ganglion & Sphenopalatine ganglion are involved in many atypical & typical facial pain conditions. If diagnostic local anesthetic injections give significant pain relief, RF lesioning is good option in these patients
- Postherpetic neuralgia (PHN) – PRF lesioning of dorsal root ganglion (DRG) can be tried to relieve pain due to chronic PHN.
- Complex regional pain syndrome (CRPS) – Previously known as Reflex Sympathetic Dystrophy.
- Diabetic painful neuropathy effective in patients with long standing diabetics – radiofrequency ablation of sympathetic system
- Pain due to vascular insufficiency with sympathetic mediated pain
- Cancel Pain – and Many More
The advantages of radiofrquency lesioning
- Lesion size can be accurately controlled, allowing lesioning of small nerves without damaging nearby motor and other sensory nerves.
- Recovery is rapid and usually uneventful, allowing the patient to return to work or normal daily activity more quickly.
- The nerve lesion is usually long-lasting. An accurately done lesion may give pain relief for years.
- Nerve lesion heals without neuroma formation
- The rate of side effects and complications is low.
- When pain recurs, nerve lesion can be repeated as necessary.
Contraindications and limitations
- Pain control with nerve lesioning is a palliative measure and, therefore, should not be considered in place of corrective surgical treatment.
- Before the procedure, the patient must have realistic expectations and must understand that the aim is to reduce the pain, not stop it completely.
- Before neurodestructive proceudres, diagnostic blocks should give good pain relief. The same diagnostic block should be repeated at least once more, even if the pain relief from the first block was excellent, to decrease the chance of placebo effect. If the result is not clear, differential blocks should be used.
- Patients with pain complaints at multiple locations or with wide distribution of pain usually respond poorly to RF procedures.
The patient must realize that single target lesioning may not be sufficient, necessitating complementary blocks for better pain relief.