Pulsed Radiofrequency: A Management Option for Recurrent Trigeminal Neuralgia Following Radiofrequency Thermocoagulation

Elucidating the Mechanisms of Pulsed Radiofrequency for Pain Treatment

Pulsed radiofrequency is a well-documented treatment option for multiple painful conditions where pulses of energy are delivered close to neural elements. Since its earliest adoption, this technique has gained increasing acceptance as a minimally invasive procedure, and new applications are evolving. Studies have shown microscopic and biochemical changes that reflect beneficial effects; however, the exact mechanism of action is not yet completely understood. To redress this paucity, 11,476 articles of scientific relevance published between 1980 and November 2022 were mined through a search of the PubMed database, arriving at 49 studies both in animals and humans. In general, the experimental studies examined have shown that pulsed radiofrequency induces multiple changes with antinociceptive and neuromodulatory effects. These modifications include changes in neural and glial cells, synaptic transmission, and perineural space. Studies also reveal that pulsed radiofrequency regulates inflammatory responses, cellular signaling proteins, and the expression of genes related to pain transmission, acting in biological processes in structures such as myelin, mitochondria, axons, glial cells, connective tissue, regulation of proteins, ion channels, and neurotransmitters.

CT-Guided Thermocoagulation of the Pterygopalatine Ganglion for Refractory Trigeminal Autonomic Cephalalgia

INTRODUCTION

Trigeminal autonomic cephalalgia (TAC) is a type of one-sided cerebral painful headache, with attacks regularly accompanied by autonomic responses, such as tearing, runny nose, panic, nausea and vomiting on the affected side. Currently, the most common treatment strategies are drugs, nerve grafts and surgery. Clinical understanding of TACs is limited. Here, we report the case of thermocoagulation treatment of the pterygopalatine ganglion in an uncommon TAC under local anesthesia.

CASE PRESENTATION

A rare case of TAC was treated with computed tomography (CT)-guided thermocoagulation within the pterygopalatine ganglion. Pain and autonomic signs were relieved immediately after surgery, with the patent retaining only slight numbness on the left side of the face. This numbness completely resolved at 6 months of follow-up and there was no recurrence.

DISCUSSION

Trigeminal autonomic cephalalgia seriously affects the patient's quality of life, but clinical understanding is limited. In the case reported here, we performed CT-guided thermocoagulation of the pterygopalatine ganglion at 90 °C for 180 s for treatment of a trigeminal autonomic headache. To our knowledge, this is the first report of using thermocoagulation at 90 °C to treat the pterygopalatine ganglion. We found that this strategy results in fewer side effects and is a more cost-effective treatment for such patients than other options.

CONCLUSION

Computed tomography-guided thermocoagulation of the pterygopalatine ganglion at 90 °C for 180 s for treatment of trigeminal autonomic headache is a safe and economical treatment option.

Recent Advances in Trigeminal Neuralgia and Its Management: A Narrative Review

Trigeminal neuralgia (TN) is a chronic facial pain condition that affects one or more divisions of the trigeminal nerve (5th cranial nerve). It can be idiopathic, primary, or secondary. The cornerstone of the therapy has been antiepileptic medications, peripheral nerve blocks with various neurolytic agents, and surgical procedures. With the advent of newer technologies, minimally invasive neurolytic techniques like low-level laser therapy and ozone injection have revolutionized the management of TN. Novel drugs like vixotrigine and eslicarbazepine have been promising in reducing the frequency and severity of attacks. Inhaled carbon dioxide too has shown promising results in initial trials. Neuromodulation has given robust data in controlling neuralgic pain especially refractory to medical management. Pulsed radiofrequency has been used with increasing success and the side effects like dysesthesia and paresthesia are less. Cryotherapy, neural prolotherapy, and fiber knife techniques have helped us believe that TN can be controlled and cured. The need of the hour is to develop and explore newer modalities for trigeminal neuralgia treatment with minimum side effects. In this narrative review, we have tried to shed light into the newer modalities of treatment of TN along with new clinical classification for better disease recognition and management.

Predictors of the Analgesic Efficacy of CT-Guided Percutaneous Pulsed Radiofrequency Treatment of Gasserian Ganglion in Patients With Idiopathic Trigeminal Neuralgia

AIMS

Although pulsed radiofrequency (PRF) has few postoperative adverse reactions, its analgesic efficacy for trigeminal neuralgia (TN) is not always guaranteed. The response rate of PRF targeting the Gasserian ganglion for patients with TN varies. This study aims to identify the predictors of the analgesic efficacy of CT-guided percutaneous PRF in patients with idiopathic TN.

METHODS

The patients with idiopathic TN who failed to respond to conservative treatment and underwent CT-guided percutaneous PRF treatment of the Gasserian ganglion from July 2008 to August 2018 at our pain clinic were screened. A positive response was defined as a ≥50% reduction in the pain numeric rating scale (NRS) score from baseline. The demographics and other pretreatment clinical data were analyzed by logistic regression analysis to identify the predictors of a positive response.

RESULTS

Of the total 102 patients with idiopathic TN who were evaluated in this study, 57 patients (55.9%) were positively responsive to our treatment after 1 year. The binary logistic regression analysis revealed that the positive response to a prior peripheral branch nerve block of the trigeminal nerve with steroid and local anesthetic agents was an independent predictor of the analgesic efficacy of PRF treatment (odds ratio [OR] = 3.685, 95% confidence interval [CI] = 1.583 to 8.577, P = 0.002). The disease duration of TN was also included in the multivariate regression model, although the P value was 0.058 (OR 0.807, 95% CI 0.646 to 1.007).

CONCLUSION

For patients who previously had positive responses to peripheral branch nerve block of the trigeminal nerve, PRF is likely to have better efficacy.

Efficacy and Safety of Repeated Percutaneous Radiofrequency Thermocoagulation for Recurrent Trigeminal Neuralgia

Background: Percutaneous radiofrequency thermocoagulation (PRT) is used to treat trigeminal neuralgia (TN) with a satisfactory pain relief but a high recurrence rate. Objective: To explore the efficacy and safety of repeated PRT for recurrent TN as compared to patients who received the first PRT. Methods: Between January 2013 to May 2013, 31 patients with recurrent TN who have been treated with PRT previously were recruited and underwent repeated PRT (group A), and compared with 41 TN patients received the first initial PRT (group B). Visual Analog Scale (VAS) score was assessed preoperatively and postoperatively after 2 years of follow-up, and compared in terms of initial pain relief, complications, and recurrence rate between the two groups. Results: In group A, 27 patients (87.0%) were pain free immediately, and 30 patients (96.8%) experienced pain relief at 48 h, whereas that was 37 patients (90.0%) and 40 patients (97.6%) in group B (p ≧ 0.05). Patients in group A who remained an "excellent" or "good" pain relief condition (VAS score ≦ 1) were 96.8% at 6 months, 83.9% at 1 year, 74.2% at 2 years, whereas the percentage in group B was 97.6, 85.4, and 73.2% (p ≧ 0.05). Conclusion: For patients with recurrent TN after PRT, repeated PRT might be considered as a useful treatment option when other treatments fail. In addition, the frequency and severity of adverse events for repeated PRT were similar as compared to initial PRT.