Long-term Follow-up of Pulsed Radiofrequency Treatment for Trigeminal Neuralgia: Kaplan-Meier Analysis in a Consecutive Series of 149 Patients.

BACKGROUND: At present, there is no ideal method for the treatment of trigeminal neuralgia (TN). The need for an easy, safe, non- or micro-neurodestructive, repeatable treatment, with a fairly satisfactory rate of pain relief, is paramount. Pulsed radiofrequency (PRF) as a minimally invasive and microdestructive technique has been reported to be an option for TN; however, no study has reported the long-term outcome of TN in a large case series. OBJECTIVES: We aimed to investigate the efficacy, safety, and the long-term outcomes of PRF treatment for patients with TN. STUDY DESIGN: This was a long-term, large case series, retrospective study. SETTING: The study was conducted at Tiantan hospital,Beijing. METHODS: We retrospectively analyzed medical databases and follow-up data of 149 patients with TN from January 2008 through March 2021, who underwent PRF treatment, with a median follow-up time of 71.0 months (interquartile range, 20.0 months to 112.0 months). Baseline characteristics and intraoperative data of patients were retrospectively extracted; data about complications and side effects were also collected. The follow-up data were composed of the postoperative Barrow Neurological Institute Pain Intensity Score  pain intensity at a different time, the onset time of PRF treatment, and the time when pain was recurrent. RESULTS: The initial pain relief rate was 75.17% after the procedure. The cumulative recurrence-free survival after the procedure was 75.00% at one month; 72.87% at 6 months; 70.59% at 12 months; 65.39% at 24 months; 61.63% 48 months; 56.73% at 96 months; and 49.64% at 144 months. The median recurrence-free time was 118 months according to the Kaplan-Meier estimator. Nineteen patients had pain recurrence with a median time of 15 months (range, 1.0 months to 96.0 months), among whom, 12 underwent a second PRF procedure and 9 patients experienced satisfactory pain relief. No serious complications or side effects occurred after the procedure. LIMITATIONS: This was a single-center, retrospective study. Our study failed to conduct a stratified analysis on the effect of PRF treatment for classic and idiopathic TN. The most efficacious parameters of PRF applied for TN and studies trying to identify positive predictive factors of pain relief before PRF treatment have yet to be investigated. CONCLUSIONS: The results of this study show the promising long-term effect of PRF on primary TN. The safety and repeatability might be more easily accepted by patients with TN and should be considered a preferred treatment option before choosing neurodestructive or more invasive methods.

The Long-Term Outcome of 3-Dimensional CT-Guided Percutaneous Radiofrequency Thermocoagulation for Tumor-Related Trigeminal Neuralgia.

BACKGROUND: Percutaneous radiofrequency thermocoagulation (PRFT) has been widely used to treat trigeminal neuralgia. By querying MEDLINE, EMBASE, and the Cochrane Library, no study has reported the long-term outcome of PRFT for tumor-related trigeminal neuralgia (TRTN). OBJECTIVES: In this study, we aimed to evaluate the long-term efficacy and safety of PRFT as an alternative treatment for TRTN. STUDY DESIGN: A retrospective study. SETTING: The interventional pain management center in Beijing Tiantan hospital. METHODS: We retrospectively analyzed data of all patients who underwent PRFT applied to the Gasserian ganglion under computed tomography guidance for TRTN through a combination of available institutional electronic medical records, patient notes, and radiologic images. RESULTS: Among 38 patients with PRFT treated between March 2007 and February 2018, 13 patients were men and 25 were women. All patients were evaluated as modified Barrow Neurological Institute (BNI) IV-V before the operation and had a total symptom duration of 45.55 ± 23.31 months. The mean operation duration was 59.63 ± 16.89 minutes. All patients experienced satisfactory pain relief defined as a classification of BNI I-IIIb within 3 days after PRFT. The median remission length with satisfactory pain relief was 33 (range, 4-132) months. No serious intraoperative complications, except bradycardia in 6 patients, were recorded. Postprocedure complications, including masticatory muscle weakness, were reported in 5 patients. Although all 38 patients experienced facial dysesthesia, the patients' Likert scale rating represented that quality of life significantly increased after the procedure. LIMITATIONS: The small sample size may have unavoidably caused selection bias in our study. Larger prospective, randomized, multicenter trials are necessary to validate our outcomes. CONCLUSIONS: PRFT is an effective and safe treatment that should be considered as an alternative for pain control in the treatment of TRTN. KEY WORDS: Pain, secondary trigeminal neuralgia, radiofrequency thermocoagulation, trigeminal neuralgia.

Efficacy and safety of CT-guided percutaneous pulsed radiofrequency treatment of the Gasserian ganglion in patients with medically intractable idiopathic trigeminal neuralgia.

BACKGROUND: There is a lack of prospective studies for the long-term results of percutaneous pulsed radiofrequency (PRF) of the Gasserian ganglion in the treatment of patients with medically refractory trigeminal neuralgia (TN). METHODS AND RESULTS: We prospectively observed the outcomes of 28 idiopathic TN patients (between July 2013 and July 2016) who received CT-guided percutaneous PRF treatment of the Gasserian ganglion. All of the patients had stopped responding to drug therapy before PRF treatment. The effective treatment standard was a reduction in the pain numeric rating scale (NRS) by ≥50% after the procedure. The postoperative NRS score decreased gradually from preoperative 7.6±0.8 months to 1.5±2.4, 0.2±0.4, 0.2±0.4, 0.1±0.4, and 0.1±0.4 at 1, 3, and 6 months and 1 and 2 years after the PRF treatment. The response rates at 1, 3, and 6 months were 85.7%, and the rates at 12 months and 2 years were maintained at 78.6%. No serious side effects were observed. CONCLUSION: CT-guided PRF invention is an effective and safe technique for medically intractable idiopathic TN patients. This minimally invasive alternative treatment has the potential as a first-line therapy for TN.

Pulsed Radiofrequency Improves Neuropathic Pain in Chronic Constriction Injury Rats through the Upregulation of the Transcription and Translation Levels of Glial Cell Line-Derived Neurotrophic Factor.

BACKGROUND: Several studies in recent years have confirmed that the direct application of pulsed radiofrequency (PRF) on peripheral nerve compression points can alleviate hyperalgesia in animal models of neuropathic pain (NP). However, the mechanism underlying the treatment of peripheral nerves by PRF is unclear. OBJECTIVES: We aim to observe changes in pain behavior after the application of PRF on the ligation site of the sciatic nerves (SNs) of rats with chronic constriction injury (CCI) and to investigate the effects of PRF on the transcription and translation levels of glial cell line-derived neurotrophic factor (GDNF) in nerve tissues at the treatment site. STUDY DESIGN: A randomized, experimental trial. SETTING: Experimental Animal Center, Beijing Tiantan Hospital. METHODS: Ninety-six adult male Sprague-Dawley rats were randomly divided into 4 groups: sham-sham (SS) group, sham-PRF (SP) group, CCI-sham (CS) group, and CCI-PRF (CP) group. The right SNs of rats in the CS and CP group were ligated to establish the CCI model. The right SNs in the SS and SP groups were isolated and exposed but without being ligated. On the fourteenth day after CCI/sham operation, PRF treatment was performed on the midpoint of the ligation sites of the SN in the CP group and the corresponding sites in the SP group. The electrode was only placed at the ligation sites of the SN in the CS group and the corresponding sites in the SS group without current being applied. The 50% paw withdrawal threshold (50%PWT) and thermal withdrawal latency (TWL) of rats in all of the groups were measured. The transcription and translation levels of GDNF of the PRF/sham treatment sites were measured before and after treatment by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assays (ELISAs). RESULTS: The 50%PWT value of the hind paws of rats in the CP group gradually increased on day 6 after the PRF treatment and was significantly higher than that in the CS group (6 days after treatment P < 0.05; 14 days after treatment P < 0.01). The TWL value in the CP group was higher than that in the CS group 2 days after treatment (P < 0.05) and was significantly higher (P < 0.01) from day 6 until the end of the experiment. On the day 6 and 14 after PRF treatment, the mRNA and protein expression levels of GDNF at the ligation sites of the SNs of rats in the CP group were higher than both the levels before treatment and those in the CS group (P < 0.01). LIMITATIONS: The efficacy of PRF treatment in the CCI model was only tested within 14 days, and the changes in GDNF levels were only tested at 3 time-points before and after treatment. CONCLUSIONS: The direct application of PRF on SN ligation sites in the CCI model can safely and effectively alleviate NP. One of the mechanisms of this effect could be the upregulation of the transcription and translation of GDNF in compressed SNs. KEY WORDS: Pulsed radiofrequency, chronic constriction injury, sciatic nerve, 50% paw withdrawal threshold, thermal withdrawal latency, glia cell line-derived neurotrophic factor, reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay.

Effects of Pulsed Radiofrequency on Ultrastructure and Glial Cell Line-derived Neurotrophic Factor Expression in Sciatic Nerve Chronic Constriction Injury Rats / 中国康复理论与实践

Objective To observe the hindpaw withdrawal threshold (HWT), and the ultrastructure and expression of glia cell line-de-rived neurotrophic factor (GDNF) in sciatic nerve (SN) in chronic constriction injury (CCI) rats after pulsed radiofrequency (PRF). Meth-ods 30 Sprague-Dawley rats were divided into sham modeling-sham treating (SS) group, CCI-Sham treating (CS) group and CCI-PRF (CP) group. The right SNs of the rats in the CS and CP groups were ligated, and it was separated without ligation in the SS group. The CP group accepted PRF at the ligation 14 days after modeling, while the electrodes were placed without electricity in the SS and CS groups. Their HWT was measured before and 1, 7, 14 days after modeling, and 1, 7, 14 days after treatment. The right SN of ligation was observed under electron microscope 14 days after treatment, meanwhile, the GDNF expression was determined with enzyme-linked immunosorbent assay (ELISA). Results HWT was significantly shorter in the CS and CP groups than in the SS group after modeling, and it increased in the CP group 14 days after treatment compared with that of the CS group (P<0.01). The degeneration of SN significantly improved in the CP group compared with the CS group, while the expression of GDNF increased compared with that in the CS and SS groups (P<0.01). Conclusion PRF could relieve the CCI-induced neuropathic pain by upregulating the GDNF expression in the SN to prevent the SN from injury.