Jan Van Zundert

Pulsed and continous radiofrequency current adjacent to the cervical dorsal root ganglion of the rat induces late cellular activity in the dorsal horn

Background: Pulsed radiofrequency treatment has recently been described as a non-neurodestructive or minimally neurodestructive alternative to radiofrequency heat lesions. In clinical practice long-lasting results of pulsed radiofrequency treatment adjacent to the cervical dorsal root ganglion for the management of chronic radicular spinal pain have been reported without neurologic complications. However, the mode of action is unclear. An early (3 h) effect of pulsed radiofrequency as measured by an increase of c-Fos in the pain-processing neurons of the dorsal horn of rats has been described in the literature. This effect was not mediated by tissue heating. The authors investigated a possible late or long-term effect of three different radiofrequency modalities. Methods: Cervical laminectomy was performed in 19 male Wistar rats. The cervical dorsal root ganglion was randomly exposed to one of the four interventions: sham, continuous radiofrequency current at 67 centigrades, or pulsed radiofrequency current for 120 s or 8 min. The animals were sacrificed and the spinal cord was prepared for c-Fos labeling 7 days after the intervention. Results: The number of c-Fos immunoreactive cells in the dorsal horn was significantly increased in the three different radiofrequency modalities as compared with sham. No significant difference was demonstrated between the three active intervention groups. Conclusions: The authors demonstrated a late neuronal activity in the dorsal horn after exposure of the cervical dorsal root ganglion to different radiofrequency modalities, which was not temperature dependent.

Pulsed radiofrequency adjacent to the cervical dorsal root ganglion in chronic cervical radicular pain: A double blind sham controlled randomized clinical trial

Abstract Cervical radicular pain affects approximately 1 on 1000 adults per year. Although many treatment modalities are described in the literature, the available evidence for efficacy is not sufficient to allow definitive conclusions on the optimal therapy to be made. The effect of pulsed radiofrequency treatment for this type of patients was evaluated in a prospective audit that showed satisfactory pain relief for a mean period of 9.2 months, justifying a randomized sham controlled trial. Twenty‐three patients, out of 256 screened, met the inclusion criteria and were randomly assigned in a double blind fashion to receive either pulsed radiofrequency or sham intervention. The evaluation was done by an independent observer. At 3 months the pulsed radiofrequency group showed a significantly better outcome with regard to the global perceived effect (>50% improvement) and visual analogue scale (20 point pain reduction). The quality of life scales also showed a positive trend in favor of the pulsed radiofrequency group, but significance was only reached in the SF‐36 domain vitality at 3 months. The need for pain medication was significantly reduced in the pulsed radiofrequency group after six months. No complications were observed during the study period. These study results are in agreement with the findings of our previous clinical audit that pulsed radiofrequency treatment of the cervical dorsal root ganglion may provide pain relief for a limited number of carefully selected patients with chronic cervical radicular pain as assessed by clinical and neurological examination.

Radiofrequency and Pulsed Radiofrequency Treatment of Chronic Pain Syndromes: The Available Evidence

There are currently 6 reviews on (pulsed) radiofrequency (RF) for the management of spinal pain. Two reviews on interventional pain management techniques in general also discuss RF. The outcomes of those reviews depend on the type of studies included and the opinion of the reviewers, which may result in different evidence levels.

11. Lumbosacral Radicular Pain

Lumbosacral radicular pain is characterized by a radiating pain in one or more lumbar or sacral dermatomes; it may or may not be accompanied by other radicular irritation symptoms and/or symptoms of decreased function. The annual prevalence in the general population, described as low back pain with leg pain traveling below the knee, varied from 9.9% to 25%, which means that it is presumably the most commonly occurring form of neuropathic pain.

Evidence-based guidelines for interventional pain medicine according to clinical diagnoses.

The World Institute of Pain mission includes teaching and education to achieve excellence in pain practice. Evidence-Based Medicine (EBM) is an important tool to reach this goal. The EBM section of Pain Practice aims to present articles reviewing the current evidence on specific treatments, but attention is also paid to methodological issues. Interventional pain management techniques have gained a definite place in the management of chronic pain syndromes. The number of publications on these techniques is increasing; at the time of writing there are approximately 60 randomized controlled trials (RCTs). Most of them report studies on radiofrequency procedures, but spinal cord stimulation and epidural corticosteroid injections have also been studied. The available literature on interventional diagnostic and therapeutic procedures for spinal pain has been summarized in evidence-based practice guidelines, a work that was updated 2 years later. These guidelines provide an excellent review of the literature. But from a practical point of view, the outcome data on a given technique are not directly linked to a specific diagnosis. However, there are several studies indicating that the chances of a successful treatment outcome increase with a better subdiagnosis. Hence, the importance of the diagnostic process, which is the cornerstone for establishing a treatment plan that is not limited to interventional procedures, but relies on accurate use of conservative treatment, potentially in association with interventional pain management techniques. Therefore, EBM practice guidelines must be specific for every different pain diagnosis. This concept will provide the basis for the content of an upcoming series in the EBM section of Pain Practice. Inclusion of interventional pain management techniques in the patient’s treatment plan should be guided by the best available evidence on efficacy and safety with respect to the diagnosis of the individual patient, because careful analysis of the literature provides proof that better patient selection increases the chances of a positive treatment outcome. Moreover, for correct application of interventional pain management techniques, a good Address correspondence and reprint requests to: Maarten van Kleef, MD, PhD, FIPP, Maastricht University Medical Centre, Department of Anesthesiology and Pain Management, PO Box 5800, 6202 AZ Maastricht, The Netherlands. E-mail: maarten.van.kleef@mumc.nl. DOI. 10.1111/j.1533-2500.2009.00297.x

16. Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy is a pain syndrome with an unclear pathophysiology and unpredictable clinical course. The disease is often therapy resistant, the natural course not always favorable. The diagnosis of CRPS is based on signs and symptoms derived from medical history and physical examination. Pharmacological pain management and physical rehabilitation of limb function are the main pillars of therapy and should be started as early as possible. If, however, there is no improvement of limb function and persistent severe pain, interventional pain management techniques may be considered.

Treatment of Failed Back Surgery Syndrome Patients with Low Back and Leg Pain: A Pilot Study of a New Dual Lead Spinal Cord Stimulation System

Objective. Treatment of pain associated with failed back surgery syndrome was evaluated in a pilot clinical study of a new dual lead spinal cord stimulation (SCS) system.

Pulsed Radiofrequency in Lumbar Radicular Pain: Clinical Effects in Various Etiological Groups

Background:  The purpose of this study was to evaluate the effectiveness of pulsed radiofrequency (PRF) applied to the lumbar dorsal root ganglion (DRG).

8. Occipital Neuralgia

Occipital neuralgia is defined as a paroxysmal shooting or stabbing pain in the dermatomes of the nervus occipitalis major and/or nervus occipitalis minor. The pain originates in the suboccipital region and radiates over the vertex. A suggestive history and clinical examination with short‐term pain relief after infiltration with local anesthetic confirm the diagnosis. No data are available about the prevalence or incidence of this condition. Most often, trauma or irritation of the nervi occipitales causes the neuralgia. Imaging studies are necessary to exclude underlying pathological conditions. Initial therapy consists of a single infiltration of the culprit nervi occipitales with local anesthetic and corticosteroids (2 C+). The reported effects of botulinum toxin A injections are contradictory (2 C±). Should injection of local anesthetic and corticosteroids fail to provide lasting relief, pulsed radio‐frequency treatment of the nervi occipitales can be considered (2 C+). There is no evidence to support pulsed radio‐frequency treatment of the ganglion spinale C2 (dorsal root ganglion). As such, this should only be done in a clinical trial setting. Subcutaneous occipital nerve stimulation can be considered if prior therapy with corticosteroid infiltration or pulsed radio‐frequency treatment failed or provided only short‐term relief (2 C+).

4. Cervical radicular pain.

Cervical radicular pain is defined as pain perceived as arising in the arm caused by irritation of a cervical spinal nerve or its roots. Approximately 1 person in 1,000 suffers from cervical radicular pain. In the absence of a gold standard, the diagnosis is based on a combination of history, clinical examination, and (potentially) complementary examination. Medical imaging may show abnormalities, but those findings may not correlate with the patients pain. Electrophysiologic testing may be requested when nerve damage is suspected but will not provide quantitative/qualitative information about the pain. The presumed causative level may be confirmed by means of selective diagnostic blocks. Conservative treatment typically consists of medication and physical therapy. There are no studies assessing the effectiveness of different types of medication specifically in patients suffering cervical radicular pain. Cochrane reviews did not find sufficient proof of efficacy for either education or cervical traction. When conservative treatment fails, interventional treatment may be considered. For subacute cervical radicular pain, the available evidence on efficacy and safety supports a recommendation (2B+) of interlaminar cervical epidural corticosteroid administration. A recent negative randomized controlled trial of transforaminal cervical epidural corticosteroid administration, coupled with an increasing number of reports of serious adverse events, warrants a negative recommendation (2B−). Pulsed radiofrequency treatment adjacent to the cervical dorsal root ganglion is a recommended treatment for chronic cervical radicular pain (1B+). When its effect is insufficient or of short duration, conventional radiofrequency treatment is recommended (2B+). In selected patients with cervical radicular pain, refractory to other treatment options, spinal cord stimulation may be considered. This treatment should be performed in specialized centers, preferentially study related.