3D CT-guided pulsed radiofrequency treatment for trigeminal neuralgia

Efficacy and Safety of High-Voltage Pulsed Radiofrequency versus Standard-Voltage Pulsed Radiofrequency for Patients with Neuropathic Pain: A Literature Review and Meta-Analysis

Background

Neuropathic pain (NP) is recognized as one of the most difficult pain syndromes which lacks a safe, well-tolerated and effective treatment. Pulsed radiofrequency (PRF), a novel and minimally invasive interventions, has been introduced to alleviate various types of NP. Previous studies reported PRF with higher voltage could further improve the treatment efficacy. Therefore, we conducted this systematic review and meta-analysis to determine whether high-voltage PRF is superior to standard-voltage PRF for the treatment of NP patients.

Methods

Databases published from the date of inception until 15 March 2022 on PubMed/MEDLINE, EMBASE, Web of Science and the Cochrane Library were searched for RCTs comparing high-voltage PRF and standard-voltage PRF in NP patients. The primary outcome measures were the efficiency rates of NP patients with high-voltage PRF or standard-voltage PRF treatment. Data analysis was conducted using the Review Manager software (RevMan V.5.3).

Results

Six RCTs involving 423 patients were included in our meta-analysis. Compared with standard-voltage PRF group, the high-voltage PRF group attained a higher efficiency rate at 1 month (P = 0.04; I2 = 0%), 3 months (P = 0.04; I2 = 0%), 6 months (P = 0.002; I2 = 0%) post-procedure respectively. There was no significant difference in the complications between the two groups.

Conclusion

Our study supported that high-voltage PRF attained more satisfactory efficacy than standard-voltage PRF without increased side effects. High-voltage PRF could be a promising, effective, minimally invasive technology for NP patients.

Effectiveness and Safety of Radiofrequency Thermocoagulation Treatment Guided by Computed Tomography for Infraorbital Neuralgia Following Failed Conservative Treatment: A Retrospective Study

Purpose

To evaluate the effectiveness and safety of CT-guided radiofrequency thermocoagulation (RFT) for the treatment of infraorbital neuralgia following the failure of conservative management.

Patients and Methods

This was a single center, retrospective study which included 196 patients between the ages of 37 to 90 years, who suffered from infraorbital neuralgia, and had undergone CT-guided RFT treatment. The medical records of these patients were retrieved between January 7, 2015 and February 5, 2020, and the patients were followed up for 2 years. Follow-up outcomes included Numerical Rating Scale (NRS) scores, dosage of carbamazepine, time to take effect, status of recurrence and side effects. The effective rate was defined as the percentage of patients with postoperative NRS score reduction of >50%.

Results

The effective rates were 92.9%, 100%, 100%, 100%, 93.4% and 85.7% on the same day, week 1, month 1, month 6, year 1 and year 2 after RFT, respectively. After RFT, the postoperative NRS scores and dosage of carbamazepine were significantly reduced than those preoperatively (P < 0.05). The median time to take effect was zero day. Twenty-eight patients with recurrence underwent RFT again and achieved complete pain relief. All patients experienced numbness in the infraorbital nerve innervation area and the numbness scores gradually decreased over time.

Conclusion

CT-guided RFT treatment may be an effective and safe technique for pain relief in patients with infraorbital neuralgia following failed results from conservative treatment.

Clinical Efficacy of a Spiral CT-Guided Balloon Compression Day-Surgery Operation for the Treatment of Trigeminal Neuralgia

Objective

This study aimed to investigate the clinical efficacy of a balloon compression day-surgery operation under the guidance of spiral computed tomography (CT) three-dimensional (3D) reconstruction for the treatment of trigeminal neuralgia.

Methods

The clinical efficacy and related indexes of 380 patients with trigeminal neuralgia treated by a spiral CT-guided balloon compression day-surgery operation in the pain department of Beijing TianTan Hospital, from October 2017 to March 2021, were retrospectively analyzed.

Results

Five patients failed due to foramen ovale puncture or in placing the balloon; two patients had ineffective results after the operation and re-entered the hospital for secondary balloon compression. The initial effective rate of the operation in the 380 patients was 98.16%. All patients were discharged on the day of the operation, the average operation time was 26.46 ± 12.15 min, and the average interval from the completion of the operation to discharge was 2.67 ± 0.95 h. During the follow-up period (1-41 months), 12 patients had pain recurrence, and a Kaplan-Meier analysis revealed that the cumulative pain-free recurrence survival rate at 41 months after the operation was 80.64%. No complications related to foramen ovale puncture occurred.

Conclusion

The spiral CT-guided balloon compression day-surgery operation is safe, effective, and worthy of clinical promotion.

Chinese expert consensus on minimally invasive interventional treatment of trigeminal neuralgia

BACKGROUND AND PURPOSE

Trigeminal neuralgia is a common condition that is associated with severe pain, which seriously affects the quality of life of patients. When the efficacy of drugs is not satisfactory or adverse drug reactions cannot be tolerated, minimally invasive interventional therapy has become an important treatment because of its simple operation, low risk, high repeatability and low cost. In recent years, minimally invasive interventional treatments, such as radiofrequency thermocoagulation (RF) of the trigeminal nerve and percutaneous microcompression (PMC), have been widely used in the clinic to relieve severe pain in many patients, however, some related problems remain to be addressed. The Pain Association of the Chinese Medical Association organizes and compiles the consensus of Chinese experts to standardize the development of minimally invasive interventional treatment of trigeminal neuralgia to provide a basis for its clinical promotion and application.

MATERIALS AND METHODS

The Pain Association of the Chinese Medical Association organizes the Chinese experts to compile a consensus. With reference to the evidence-based medicine (OCEBM) system and the actual situation of the profession, the Consensus Development Committee adopts the nominal group method to adjust the recommended level.

RESULTS

Precise imaging positioning and guidance are the keys to ensuring the efficacy and safety of the procedures. RF and PMC are the most widely performed and effective treatments among minimally invasive interventional treatments for trigeminal neuralgia.

CONCLUSIONS

The pain degree of trigeminal neuralgia is severe, and a variety of minimally invasive intervention methods can effectively improve symptoms. Radiofrequency and percutaneous microcompression may be the first choice for minimally invasive interventional therapy.

Comparison of Effectiveness and Safety between Intraoperative 3D-CT-Guided and C-Arm-Guided Percutaneous Balloon Compression for Idiopathic Trigeminal Neuralgia: A Multi-Center Retrospective Study

Objectives

To compare 3D-CT-guided and C-arm-guided percutaneous balloon compression (PBC) in terms of effectiveness and safety.

Methods

The medical records and follow-up data of patients with idiopathic trigeminal neuralgia who underwent 3D-CT-guided or C-arm-guided PBCs in Beijing Tiantan Hospital and the Characteristic Medical Center of the Chinese People's Armed Police Force between February 2018 and March 2020 were retrospectively reviewed and analysed.

Results

A total of 291 patients were included. Among them, 212 patients underwent PBC treatment with 3D-CT and others with C-arm. One (0.5%) patient in 3D-CT group and 4 (5.1%) patients in C-arm group failed to receive PBC treatment because of failure of foramen ovale (FO) puncture (P=0.020). Among patients with successful attempts, 5 (2.4%) patients in the 3D-CT group and 11 (14.7%) patients in the C-arm group received more than one needle pass during the procedure (P < 0.001). The 3D-CT group required less time than the C-arm group for puncture (P < 0.001) and for the whole operation (P < 0.001). The groups shared similar initial relief rates (P=0.749) and similar recurrence-free survival during follow-ups for a median of 22 months (P=0.839). No puncture-related complications occurred in either group and the two groups had similar incidences of compression-related complications.

Conclusion

3D-CT facilitated FO puncture and improved success rate of PBC. The overall time efficiency of PBC was also increased with 3D-CT. Thus, 3D-CT is a potentially useful image guidance technology for treating idiopathic trigeminal neuralgia by PBC.

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.

Long-Term Efficacy and Complications of Radiofrequency Thermocoagulation at Different Temperatures for the Treatment of Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a common neuropathic pain that seriously affects the daily life of patients. Many invasive treatments are currently available for patients who respond poorly to oral carbamazepine or oxcarbazepine. Among them, radiofrequency (RF) treatment is a viable option with reliable initial and long-term clinical efficacy. The long-term analgesic effects of radiofrequency thermocoagulation (RFT) at high temperatures (≥80°C) are not superior to those at relatively low temperatures (60–75°C). In contrast, the higher the temperature, the greater the risk of complications, especially facial numbness, masticatory muscles weakness, and corneal hypoesthesia. Some patients even experience irreversible lethal complications. Therefore, we recommend low-temperature RFT (60–75°C) for treatment of TN. The therapeutic effects of pulsed radiofrequency (PRF) are controversial, whereas PRF (≤75°C) combined with RFT can improve long-term effects and decrease the incidence of complications. However, large-scale clinical trials are needed to verify the efficacy of the combination of PRF and RFT.

Pulsed radiofrequency inhibits expression of P2X3 receptors and alleviates neuropathic pain induced by chronic constriction injury in rats

Background:

Pulsed radiofrequency (PRF) is a minimally invasive interventional technique that provides a novel and effective treatment strategy for neuropathic pain (NP). PRF is advantageous because it does not damage nerves and avoids sensory loss after treatment. At present, animal studies have demonstrated that PRF is safe and effective for relieving the NP associated with sciatic nerve damage in rats with chronic constriction injury (CCI). However, the mechanism through which this effect occurs is unknown. An increasing body of evidence shows that the expression of the P2X ligand-gated ion channel 3 (P2X₃) receptor is closely related to NP; this study was to investigate whether the expression of this receptor is involved in NP relief due to PRF.

Methods:

A total of 36 healthy adult male Sprague-Dawley (SD) rats were randomly divided into three groups: Sham group, CCI group, and PRF group. The right sciatic nerve was ligated in CCI group and PRF group to establish a CCI model; the right sciatic nerve was separated but not ligated in Sham group. On day 14 after the operation, PRF was administered to the ligated sciatic nerve in PRF group (42°C, 45 V, 2 min). A non-live electrode was placed at the exposed sciatic nerve for the rats in Sham and CCI groups. The hindpaw withdrawal threshold (HWT) and thermal withdrawal latency (TWL) were measured at the right hindpaw at different time points before and after PRF or sham therapy. On day 28 after treatment, the dorsal root ganglion (DRG) and spinal dorsal horn of the right L4–6 were harvested from each group to determine the mRNA and protein levels of the P2X₃ receptor.

Results:

On day 28 after PRF treatment, the HWT (8.33 ± 0.67 g vs. 3.62 ± 0.48 g) and TWL (25.42 ± 1.90 s vs. 15.10 ± 1.71 s) were significantly higher in PRF group as compared to CCI group (P < 0.05). The mRNA expression of the P2X₃ receptor in the DRG in PRF group was 23.7% lower than that in CCI group (P < 0.05), in the spinal dorsal horns in PRF group was 22.7% lower than that in CCI group (P < 0.05). The protein expression of the P2X₃ receptor in the DRG in PRF group was 27.8% lower than that in CCI group (P < 0.05), in the spinal dorsal horns in PRF group was 35.6% lower than that in CCI group (P < 0.05).

Conclusion:

PRF possibly reduces NP in CCI rats by inhibiting the expression of the P2X₃ receptor in the L4–6 DRG and spinal dorsal horns.

Combined pulsed and thermal radiofrequency versus thermal radiofrequency alone in the treatment of recurrent trigeminal neuralgia after microvascular decompression: A double blinded comparative study

BACKGROUND

Recurrent trigeminal neuralgia (RTN) is a common clinical problem and pain recurs in many patients after microvascular decompression (MVD). We evaluated the effect of adding pulsed radiofrequency to radiofrequency thermocoagulation at 60°C compared to radiofrequency thermocoagulation at 70°C alone in the treatment of recurrent trigeminal neuralgia after microvascular decompression.

METHODS

40 patients with recurrent trigeminal neuralgia after microvascular decompression were randomly divided into two equal groups. Group A: received prolonged duration of pulsed radiofrequency followed by less destructive thermocoagulation, while group B: received sole thermocoagulation. Then patients followed up for 2 years to evaluate the success rate by the Barrow Neurological Institute Pain Intensity (BNI) Scale, complications, and the need to medical treatment.

RESULTS

The success rate was 100% in both groups at discharge (BNI < III). It was 83.3% and 78.7% after 6 months, 77.8% and 68.4% after 12 month, 72.2% and 68.4% after 18 months and 66.7% and 63.1% after 24 months in group A and B, respectively (p > .05). In group A 88.9% of patients stopped tegretol treatment after the procedure compared to 84.2% in group B (p = .32). 88.9% compared to 89.5% % in group A and B, respectively, did not use tricyclic antidepressant (p = .61). The overall complications in group A was 5.61%, while it was 36.8% in group B (p = .025).

CONCLUSION

Combined pulsed and thermal radiofrequency can significantly reduce the incidence of the side effects/complications with similar success rate than using thermal radiofrequency alone in treatment of recurrent trigeminal neuralgia after microvascular decompression.

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.

The effect of ultrasound-guided percutaneous ozone injection around cervical dorsal root ganglion in zoster-associated pain: a retrospective study

Objective

This study was to evaluate the effectiveness of ultrasound-guided percutaneous ozone injections around the cervical dorsal root ganglions of zoster-associated pain (ZAP) patients.

Study design

Retrospective comparative study.

Settings

The study was conducted at a pain center of a university hospital.

Patients and methods

From June 2016 to July 2017, a total number of 30 patients with ZAP were treated with ultrasound-guided percutaneous ozone injection around the cervical dorsal root ganglion (DRG) at the injured nerve level (C2-C8). A volume of 3 mL ozone-oxygen mixture at a concentration of 30 µg/mL was injected into the area around the DRG. Patients were divided into two groups according to their disease duration: group A (at or <3 months) and group B (>3 months). The pain severity was assessed according to a visual analog scale, and imaging changes were evaluated by ultrasound. Patient improvements in pain and neurologic function were evaluated during a follow-up period from 1 to 3 months.

Results

The data showed that ozone injections reduced pain in patients with ZAP. However, the success rate of group A was higher than group B. After the injection, the von Frey data demonstrated decreases in both groups, but, there were no significant differences between the groups. Moreover, univariate logistic regression analysis and multivariate regression analysis showed a history of diabetes mellitus had a significant effect on the treatment results.

Conclusions

Percutaneous ozone injection around the DRG might be a useful method for treatment-resistant cases of ZAP at the cervical level. Institutional Review Board (IRB) approval number: HK2017-1130.

Pulsed radiofrequency in chronic pain

PURPOSE OF REVIEW

The increasing number of publications on pulsed radiofrequency (PRF) treatment of chronic pain reflects the interest for this technique. We summarize the literature for PRF in five indications: radicular pain, trigeminal neuralgia (TN), occipital neuralgia, shoulder and knee pain.

RECENT FINDINGS

The efficacy and safety of PRF adjacent to the dorsal root ganglion was documented on cervical and on lumbar level.PRF has been used for the treatment of TN. The observed duration of effect is shorter than that of conventional radiofrequency, but no neurological complications are reported with PRF.PRF of the nervi occipitales is superior to steroid injections in occipital neuralgia.Several studies showed that PRF of the nervus suprascapularis may relief shoulder pain and can improve mobility of the shoulder joint.For the treatment of knee pain, different nerves have been targeted for PRF treatment.

SUMMARY

PRF treatment has progressively gained a place in the management of chronic pain syndromes. The concept is appealing because long-lasting effects are reported without complications. Future research is needed with high quality randomized controlled trials and identification of the optimal parameters of PRF in clinical practice.

Treatment of trigeminal neuralgia by radiofrequency of the Gasserian ganglion

Trigeminal neuralgia (TN) is a neuropathic pain disorder that affects the trigeminal nerve distribution area. Pharmacological therapy has remained the first-line treatment for TN. If pharmacological intervention is not effective, surgical treatments including radiosurgery (mainly gamma knife therapy), radiofrequency (RF) of the Gasserian ganglion, and microvascular decompression have been utilized. RF is one of the most common procedures used to treat TN. Two RF approaches are commonly utilized: conventional radiofrequency (CRF) and pulsed radiofrequency (PRF). Both methods have been used to successfully treat TN; however, each procedure has distinct advantages and disadvantages. This article summarizes the current relevant literature to compare the treatment of TN with CRF vs. PRF. We discuss the treatment indications, operative methods, and complications of each treatment strategy. Most of the patients treated with CRF had a satisfactory outcome, whereas most PRF patients still had significant pain after the procedure. The application of a higher voltage can improve the curative effect of PRF, and its complications are less than CRF. Both CRF and PRF can be used to treat TN, and the former was more effective. Although the complications of CRF are more than those of PRF, most of them were short-lived and lacked sequelae. The pain relief rate in PRF-treated patients was significantly lower compared to CRF-treated patients. Furthermore, recurring pain was more commonly observed in PRF-treated patients. Therefore, CRF may be the preferred treatment option for TN, whereas treatment with PRF requires further study.

Pulsed Radiofrequency Applied to the Sciatic Nerve Improves Neuropathic Pain by Down-regulating The Expression of Calcitonin Gene-related Peptide in the Dorsal Root Ganglion

Background: Clinical studies have shown that applying pulsed radiofrequency (PRF) to the neural stem could relieve neuropathic pain (NP), albeit through an unclear analgesic mechanism. And animal experiments have indicated that calcitonin gene-related peptide (CGRP) expressed in the dorsal root ganglion (DRG) is involved in generating and maintaining NP. In this case, it is uncertain whether PRF plays an analgesic role by affecting CGRP expression in DRG. Methods: Rats were randomly divided into four groups: Groups A, B, C, and D. In Groups C and D, the right sciatic nerve was ligated to establish the CCI model, while in Groups A and B, the sciatic nerve was isolated without ligation. After 14 days, the right sciatic nerve in Groups B and D re-exposed and was treated with PRF on the ligation site. Thermal withdrawal latency (TWL) and hindpaw withdrawal threshold (HWT) were measured before PRF treatment (Day 0) as well as after 2, 4, 8, and 14 days of treatment. At the same time points of the behavioral tests, the right L4-L6 DRG was sampled and analyzed for CGRP expression using RT-qPCR and an enzyme-linked immunosorbent assay (ELISA). Results: Fourteen days after sciatic nerve ligation, rats in Groups C and D had a shortened TWL (P<0.001) and a reduced HWT (P<0.001) compared to those in Groups A and B. After PRF treatment, the TWL of the rats in Group D gradually extended with HWT increasing progressively. Prior to PRF treatment (Day 0), CGRP mRNA expressions in the L4-L6 DRG of Groups C and D increased significantly (P<0.001) and were 2.7 and 2.6 times that of Group A respectively. ELISA results showed that the CGRP content of Groups C and D significantly increased in comparison with that of Groups A and B (P<0.01). After PRF treatment, the mRNA expression in the DRG of Group D gradually decreased and the mRNA expression was 1.7 times that of Group A on the 4th day(P> 0.05). On the 8^th and 14^th days, the mRNA levels in Group D were restored to those of Groups A and B. Meanwhile, the CGRP content of Group D gradually dropped over time, from 76.4 pg/mg (Day 0) to 57.5 pg/mg (Day 14). Conclusions: In this study, we found that, after sciatic nerve ligation, rats exhibited apparent hyperalgesia and allodynia, and CGRP mRNA and CGRP contents in the L4-L6 DRG increased significantly. Through lowering CGRP expression in the DRG, PRF treatment might relieve the pain behaviors of NP.

Comparison of efficacy of continuous epidural block and pulsed radiofrequency to the dorsal root ganglion for management of pain persisting beyond the acute phase of herpes zoster

Background

There is little evidence regarding the effectiveness of intervention methods in the treatment of zoster-related pain (ZAP) after the acute phase of zoster. Generally, if ZAP remains after more than 180 days from its onset, the likelihood of pain reduction is very low; this condition is considered as a “well established” post-herpetic neuralgia (PHN). Although the clinical efficacy of intrathecal steroid injection and spinal cord stimulation (SCS) for ZAP management has been reported, these interventions are not widely used due to inherent disadvantages. Continuous epidural block is widely used in clinical practice, and the effectiveness of pulsed radiofrequency (PRF) to the dorsal root ganglion (DRG) in the treatment of ZAP already has been reported.

Objectives

The purpose of this study was to compare the clinical efficacy of continuous epidural block and DRG PRF beyond acute phase of zoster, bur before PHN was well established (from 30 days to180 days after zoster onset).

Study design

Retrospective comparative study.

Methods

A total of 42 medical records were analyzed. Patients were divided into two groups according to the type of procedure utilized: continuous epidural block (continuous epidural group) and DRG PRF (PRF group). The clinical efficacy of the procedure was evaluated using a numeric rating scale (NRS) and the medication dose before and 1 to 6 months after the procedure.

Results

There was a significant decrease in the NRS value with time in both groups. However, this decrease was more significant in the PRF group than in the continuous epidural group. The medication doses decreased significantly in the PRF group over time, but not in the continuous epidural group. The rate of clinically meaningful PHN (NRS≥3) was also lower in the PRF group than in the continuous epidural group.

Conclusions

This study revealed that DRG PRF was more effective than a continuous epidural block in treating ZAP after the acute phase of zoster. A neuromodulation method such as DRG PRF may be a useful option for reducing the progression of neuropathic changes caused by the persistent transmission of a pain signal after the acute phase of zoster.

Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a sudden, severe, brief, stabbing, and recurrent pain within one or more branches of the trigeminal nerve. Type 1 as intermittent and Type 2 as constant pain represent distinct clinical, pathological, and prognostic entities. Although multiple mechanism involving peripheral pathologies at root (compression or traction), and dysfunctions of brain stem, basal ganglion, and cortical pain modulatory mechanisms could have role, neurovascular conflict is the most accepted theory. Diagnosis is essentially clinically; magnetic resonance imaging is useful to rule out secondary causes, detect pathological changes in affected root and neurovascular compression (NVC). Carbamazepine is the drug of choice; oxcarbazepine, baclofen, lamotrigine, phenytoin, and topiramate are also useful. Multidrug regimens and multidisciplinary approaches are useful in selected patients. Microvascular decompression is surgical treatment of choice in TN resistant to medical management. Patients with significant medical comorbidities, without NVC and multiple sclerosis are generally recommended to undergo gamma knife radiosurgery, percutaneous balloon compression, glycerol rhizotomy, and radiofrequency thermocoagulation procedures. Partial sensory root sectioning is indicated in negative vessel explorations during surgery and large intraneural vein. Endoscopic technique can be used alone for vascular decompression or as an adjuvant to microscope. It allows better visualization of vascular conflict and entire root from pons to ganglion including ventral aspect. The effectiveness and completeness of decompression can be assessed and new vascular conflicts that may be missed by microscope can be identified. It requires less brain retraction.

Efficacy and safety of continuous radiofrequency thermocoagulation plus pulsed radiofrequency for treatment of V1 trigeminal neuralgia: A prospective cohort study

Patients may develop serious eye complications after continuous radiofrequency thermocoagulation (CRF) for V1 (ophthalmic division) trigeminal neuralgia (TN) at a higher temperature. Therefore, the temperature of clinical CRF for V1 TN has long been disputed, but there have few reports been found about how to achieve satisfactory pain relief, reduce the incidence rates of complications, and shorten the recovery time after CRF for V1 TN.To observe whether pulsed radiofrequency (PRF) can lead to increased rate in pain relief, reduced rate of complications, or shortened recovery time after CRF is used to treat V1 idiopathic trigeminal neuralgia (ITN).The prospective cohort study enrolled 56 patients with V1 ITN from May 2012 to April 2015. The patients were randomized into 2 treatment groups as follows: CRF only (group A, n = 28) and CRF plus PRF (group B, n = 28). The patients were followed 3 years up for pain relief, complications, and health-related quality of life (HRQoL).All the patients in either group achieved satisfactory pain relief at discharge. After treatment, patients completely pain free in group A and group B accounted for 81.6%, 92.0% at 1 year, 68.4%, 92.0% at 2 years, and 68.4%, 83.6% at 3 years, respectively. The pain relief rate was higher in group B patients than in group A, but the difference was not statistically significant. During the follow-up period, 9 (32.1%) patients in group A and 2 (7.1%) patients in group B developed recurrence (P < 0.05). Eleven patients in group A occurred corneal hypoesthesia and with recovery time was 11.9 ± 7.5 (4-18) months versus 3 patients in group B with recovery time was 3.4 ± 2.5 (2-6) months, the differences of incidence rate and recovery times were all significant (P < 0.05) between groups A and B. The mean scores of HRQoL in group B patients were higher than that in group A patients (P < 0.05).PRF after CRF results in decreased recurrence of V1 TN, reduced numbers of corneal hypoesthesia, shortened recovery time, and increased HRQoL scores. Its clinical use is recommended.

The efficacy and safety of combined pulsed and conventional radiofrequency treatment of refractory cases of idiopathic trigeminal neuralgia: a retrospective study

PURPOSE

We conducted a retrospective study to evaluate the efficacy and duration of pain relief for idiopathic trigeminal neuralgia (TN) patients after continuous radiofrequency (CRF) combined with pulsed radiofrequency (PRF) treatment of the Gasserian ganglion (GG).

METHODS

Twenty-one patients were treated with pulsed RF for 6 min repeated after rotating the needle tip by 180°, at a pulse width of 10 ms and at 45 °C. This was followed by conventional RF at 60 °C for 60 s, repeated after needle rotation by 180°, then finally at 65 °C for 60 s also repeated after needle rotation by 180°. Patients were assessed for pain intensity and consumption of analgesics at baseline and 7 days, 1 month, 6 months, and 12 months after the procedure. The patients' global impression of change (PGIC) scale was also assessed 7 days, 1 month, 6 months, and 12 months after the procedure. The incidence of facial dysthesia was evaluated 7 days after the procedure.

RESULTS

Excellent pain relief was achieved for 15 of 21 patients (71.4 %) after 1 week, 1 month, and 6 months. and for 14 of 21 patients (66.7 %) after 12 months. Consumption of analgesics was significantly reduced for more than 6 months, and for fifteen patients the PGIC scale result was very much improved 12 months after the procedure compared with baseline. Eighteen of the 21 patients (85.7 %) experienced facial dysthesia 1 week after the procedure.

CONCLUSION

Excellent pain relief and reduced consumption of analgesics for more than 6 months were observed in patients who received PRF combined with CRF to the GG for treatment of idiopathic TN.

Experience with conventional radiofrequency thermorhizotomy in patients with failed medical management for trigeminal neuralgia

Background

To evaluate the results of conventional radiofrequency thermorhizotomy (CRT) for trigeminal neuralgia (TN) in patients with failed medical management.

Methods

Patients with Trigeminal neuralgia who were referred to us for 'limited intervention' during the time frame July-2011 to Jan-2013 were enrolled for this study. CRT was administered by the Sweet technique. Pain relief was evaluated by the principle investigator.

Results

Eighteen patients were enrolled and completed a mean follow-up of 18.0 months. Pain relief was observed in 14 of 18 (77.8%) patients on the post-operative day, 14 of 18 (77.8%) at 1-month follow-up, 14 of 17 (82.4%) at 3-months follow-up, 12 of 15 (80%) at 6-months follow-up, 7 of 11 (63.6%) at 1-year follow-up and 2 of 6 (33.3%) 1.5 years of follow-up. Four patients required a repeat cycle of CRT; two at six months of follow-up and two at one year of follow-up. One patient was transferred for surgical intervention at six months of follow-up. Side-effects included facial hypoesthesia (n = 6); nausea/vomiting (n = 2), diminished corneal reflex (n = 13) and difficulty in chewing (n = 11). Severity of adverse effects gradually diminished and none of the patients who are beyond 6 months of follow-up have any functional limitation.

Conclusions

CRT is an effective method of pain relief for patients with Trigeminal neuralgia. Successful outcome (excellent or good) can be expected in 66.7% of patients after first cycle of CRF. The incidence and severity of adverse effects is less and the procedure is better tolerated by the patients.

Gene therapy for trigeminal pain in mice

The aim of this study was to test the efficacy of a single direct injection of viral vector encoding for encephalin to induce a widespread expression of the transgene and potential analgesic effect in trigeminal behavioral pain models in mice. After direct injection of HSV-1 based vectors encoding for human preproenkephalin (SHPE) or the lacZ reporter gene (SHZ.1, control virus) into the trigeminal ganglia in mice, we performed an orofacial formalin test and assessed the cumulative nociceptive behavior at different time points after injection of the viral vectors. We observed an analgesic effect on nociceptive behavior that lasted up to 8 weeks after a single injection of SHPE into the trigeminal ganglia. Control virus injected animals showed nociceptive behavior similar to naïve mice. The analgesic effect of SHPE injection was reversed/attenuated by subcutaneous naloxone injections, a μ-opioid receptor antagonist. SHPE injected mice also showed normalization in withdrawal latencies upon thermal noxious stimulation of inflamed ears after subdermal complete Freund’s adjuvans injection indicating widespread expression of the transgene. Quantitative immunohistochemistry of trigeminal ganglia showed expression of human preproenkephalin after SHPE injection.

Direct injection of viral vectors proved to be useful for exploring the distinct pathophysiology of the trigeminal system and could also be an interesting addition to the pain therapists’ armamentarium.