Interventions for Refractory Trigeminal Neuralgia: A Bayesian Mixed Treatment Comparison Network Meta-Analysis of Randomized Controlled Clinical Trials

Therapeutic Approach for Trigeminal Neuralgia: A Systematic Review

This umbrella review aimed to determine the various drugs used to treat trigeminal neuralgia (TN) and to evaluate their efficacies as well as side effects by surveying previously published reviews. An online search was conducted using PubMed, CRD, EBSCO, Web of Science, Scopus, and the Cochrane Library with no limits on publication date or patients' gender, age, and ethnicity. Reviews and meta-analyses of randomized controlled trials pertaining to drug therapy for TN, and other relevant review articles added from their reference lists, were evaluated. Rapid reviews, reviews published in languages other than English, and reviews of laboratory studies, case reports, and series were excluded. A total of 588 articles were initially collected; 127 full-text articles were evaluated after removing the duplicates and screening the titles and abstracts, and 11 articles were finally included in this study. Except for carbamazepine, most of the drugs had been inadequately studied. Carbamazepine and oxcarbazepine continue to be the first choice for medication for classical TN. Lamotrigine and baclofen can be regarded as second-line drugs to treat patients not responding to first-line medication or for patients having intolerable side effects from carbamazepine. Drug combinations using carbamazepine, baclofen, gabapentin, ropivacaine, tizanidine, and pimozide can yield satisfactory results and improve the tolerance to the treatment. Intravenous lidocaine can be used to treat acute exaggerations and botulinum toxin-A can be used in refractory cases. Proparacaine, dextromethorphan, and tocainide were reported to be inappropriate for treating TN. Anticonvulsants are successful in managing trigeminal neuralgia; nevertheless, there have been few studies with high levels of proof, making it challenging to compare or even combine their results in a statistically useful way. New research on other drugs, combination therapies, and newer formulations, such as vixotrigine, is awaited. There is conclusive evidence for the efficacy of pharmacological drugs in the treatment of TN.

Efficacy of medications in adult patients with trigeminal neuralgia compared to placebo intervention: a systematic review with meta-analyses

Background

Trigeminal neuralgia (TN) is characterized by brief, unilateral, sharp, stabbing, and shooting pain of the fifth cranial nerve. The objective of this systematic review with meta-analysis was to determine the effect of medications compared to placebo in adult patients with TN.

Methods

Review authors identified randomized placebo-controlled trials (RCTs) from PubMed, Web of Science, Cochrane, and EMBASE up to February 2021. We assessed the inclusion and exclusion criteria as well as the risk of bias of the studies based on the Cochrane Handbook. A total of 324 unduplicated references were scanned independently and reduced to eight relevant RCTs, with 89 patients included. Medications investigated included oral carbamazepine, subcutaneous sumatriptan, lidocaine (intranasal, 8% spray on the oral mucosa or intravenous), buprenorphine (ganglionic local opioid analgesia), and oral Nav1.7, a selective sodium channel blocker.

Results

Meta-analyses showed that overall patients receiving lidocaine reported a significantly lower post-treatment intensity of pain -3.8 points on a 0-10 scale (95% Cl = -4.653 to -2.873; P < 0.001). Patients who received lidocaine were 8.62 times more likely to have pain improvement than patients on placebo (P < 0.001). In one RCT, patients receiving oral carbamazepine showed a significant improvement in pain intensity of -32% compared to the placebo (P < 0.001). In one trial, patients receiving 3 mg subcutaneous sumatriptan had a significantly lower intensity of pain on average -6.1 points on a scale of 0-10 compared to placebo (P < 0.001) and a significant improvement in pain intensity of -75% compared to the improvement in the placebo group (P < 0.001). Patients who received subcutaneous sumatriptan were 10 times more likely to have pain improvement than those who received placebo (P = 0.001) in one study. Due to the unclear/high risk of bias and small sample size, the quality of the evidence for lidocaine in the treatment of TN was low.

Conclusion

Further studies are needed for carbamazepine, sumatriptan, buprenorphine, and oral Nav1.7 sodium channel blockers, as only one study reported outcomes.

Efficacy and safety of radiofrequency in the treatment of trigeminal neuralgia: a systematic review and meta-analysis

To assess the effectiveness of radiofrequency (RF) versus other percutaneous strategies (balloon compression, glycerol rhizotomy [GR], and microvascular decompression [MVD]) in patients with trigeminal neuralgia. We systematically searched the electronic databases of PubMed, Embase, and the Cochrane Library to identify eligible studies throughout October 2020. The odds ratio (OR) with 95% confidence interval (CI) was applied to assess effect estimates using the random-effects model. Eighteen retrospective cohort studies that enrolled 6391 patients with trigeminal neuralgia were included. We noted that RF was associated with an increased incidence of immediate pain relief compared with GR (OR 2.65; 95% CI 1.29-5.44; P = 0.008). Moreover, RF was associated with an increased risk of pain recurrence compared with MVD (OR 3.80; 95% CI 2.00-7.20; P < 0.001). Furthermore, RF was associated with an increased incidence of postoperative anesthesia compared with GR (OR 3.01; 95% CI 1.11-8.13; P = 0.030) or MVD (OR 4.62; 95% CI 2.15-9.93; P < 0.001). This study found that RF was superior to GR for the improvement in immediate pain relief; whereas, RF yielded an excess risk of pain recurrence compared with MVD. Moreover, the incidence of postoperative anesthesia in patients treated with RF significantly increased compared with the incidence after treatment with GR and MVD.

Efficacy of Botulinum Toxin Type A in Trigeminal Neuralgia in a South Asian Cohort

Introduction:

The antinociceptive effect of botulinum toxin-A (BTX-A) in trigeminal neuralgia (TN) has been described. We evaluated effects of BTX-A in relieving pain in patients with refractory TN at National Hospital of Sri Lanka.

Materials and Methods:

Pain in patients with TN was assessed using a visual analog from 0 to 10. Three months after commencement of drug therapy with ≥2 drugs including one first-line drug (carbamazepine/oxcarbazepine), pain scores were re-assessed. Twenty-two patients who did not report improvement of ≥50% at 90 days’ posttreatment were recruited. They were given adjunct BTX-A directly to the trigger point (if identified) or intradermal. Pain scores were assessed at 10, 20, 30, 60, and 90 days’ posttreatment.

Results:

There was a statistically significant improvement in mean pain scores at 10, 20, 30, 60, and 90 days’ posttreatment (5.59 [standard deviation (SD) = 2.7], 5.68 [SD = 2.6], 5.27 [SD = 3.2], 4.77 [SD = 3.7], and 5.32 [SD = 4.0]) compared to pre-BTX-A treatment (7.14, SD = 2.2). Percentage reduction in mean pain score ranged from 20.4% to 33.1%. Maximum response was at day 60 post-BTX-A (50% had ≥50% reduction in pain). No significant difference was found in response with higher doses and injection strategy.

Conclusion:

Consistent statistically significant reductions in pain scores at the aforesaid intervals compared to pretreatment means that there is a place for BTX in refractory TN.