Principles and Uses of Radiofrequency Nerve Lesioning in Chronic Pain Control
Author: Ahmet H. Ozturk, MD
Medical Director, CHH Pain Management Clinic
In the management of chronic pain, the value of permanent nerve blocks has long been recognized. To this end, several surgical and nonsurgical methods have been devised. Surgical techniques are usually more involved and serve as a last resort. Surgical transection of peripheral nerves may cause neuroma formation and deafferentation pain. After surgical lesioning of sympathetic nerves, symptoms may recur and surgical re-exploration may be difficult or impossible. Such considerations lead to a search for nonsurgical nerve destruction techniques. Three methods of nerve destruction are generally accepted:
- Injection of neurolytic substances, such as absolute alcohol, phenol or glycerin, are done under X-ray and are suitable for the destruction of larger units like celiac plexus. The size of the lesion is difficult to predict, and the spread of neurolytic substance may cause unwanted side effects that will also be permanent.
- Cryoanalgesia (freezing of a peripheral nerve) is more accurate but has the disadvantage of being short term, usually three to six months.
- Radiofrequency (RF) lesioning is a more refined technique based on the thermocoagulation of selected nerves using an electrode capable of accurate temperature generation.
The advantages of radio frequency 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.
- Patients with significant psychological problems, such as those with secondary pain and drug dependency, are not suitable candidates for any type of intervention, especially neurodestructive pain control procedures. Such patients are likely to continue with pain behavior and complaints of pain even if the procedure was successful.
- 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 procedures, 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.
- Lesioning of mixed nerves is avoided because it may cause deafferentation of the skin and muscular weakness.
- Deafferentation pain may be aggravated by further destruction of the affected nerve. When pain is of central origin (spinal or higher), destruction of the peripheral nerve may cause increased pain perception by eliminating incoming stimuli. A better alternative in such cases is neuroaugmentation with TENS or a spinal cord stimulator.
- All etiologic treatments, including surgery, have been tried and have failed.
- All palliative nondestructive conservative treatment, including temporary nerve blocks, steroids and physical therapy, have been tried and have failed.
- Patient factors are important; the patient should be free of significant psychological problems and drug dependency, be motivated and have realistic expectations.
- The patient should respond favorably to repeated diagnostic trial blocks.
Facet joint pain:
Pain originating from facet joints is a common component of low back and neck pain. This mechanical aspect of back pain is usually not amenable to surgical intervention and is difficult to manage conservatively. Epidural cortisone injections may be used, but provide limited pain relief and are of short duration. RF lesioning of the medial branch of posterior primary ramus effectively denervates the facet joint and provides long-term, good-quality pain relief in selected patients. Facet rhizotomy has a success rate of 60-70 percent. Considering that little can be done for patients with chronic low back and/or neck pain other than medications and physical therapy, this success rate is quite acceptable. A successful RF facet rhizotomy usually gives pain relief for more than a year.
Pain originating from intervertebral discs is another common source of 10w back and neck pain. Surgery is rarely indicated if the disc is not herniated and impinging on the nerve root. A disc appearing normal or only bulging in radiological studies may be a significant source of pain due to internal derangement. Annulus fibrosis is densely innervated by the sinuvertebral nerve and by the gray rami communicans. After identifying the painful disc with provocative discogram and pain suppression tests, RF lesioning may be used to partially denervate the disc either by lesioning of the rami communicans or by intradiscal denervation techniques. RF disc denervation is contraindicated if there is disc herniation with nerve impingement, multiple level disc disease, advanced degenerative disc disease and negative provocative discogram.
Coccygodynia and rectalgia:
Pain at the tailbone due to organic causes may be alleviated by RF lesioning of the coccygeal nerve and/or ganglion impar. Trial blocks are always done at least twice to confirm that the condition is organic in etiology.
Sympathetically mediated pain:
Pain that is transmitted via sympathetic nerves may be interrupted by lesioning of the sympathetic chain at the spinal level or at the stellate ganglion. Sympathetic denervation is also valuable for control of ischemic pain due to peripheral vascular insufficiency, both by decreasing pain and increasing blood flow.
Partial rhizotomy of dorsal root ganglion may provide pain relief for nociceptive radicular pain, as an alternative to spinal cord stimulation when surgery is not indicated or feasible.
Other uses of RF lesioning include treatment of trigeminal neuralgia by thermocoagulation of Gasserian ganglion, lesioning sphenopalatine ganglion and stereotactic cordotomy in cancer patients.
- Last updated: 06/22/2011