Trigeminal neuralgia is a rare condition that causes excruciating intermittent, short-lasting facial pain that is usually unilateral, is typically provoked by light touch, and is often mistaken initially as a tooth pain. First-line treatment involves anticonvulsant drugs, generally carbamazepine or oxcarbazepine, but other agents are also used. These drugs can provide significant initial pain relief, but with time response becomes poorer despite escalating doses. Side effects also increase significantly. Patients may then be referred for surgery or treated with second-line medications, although there is little or no evidence to guide these choices.
Focus of the review
Trigeminal neuralgia can be managed both medically and surgically with varying outcomes. This review identifies the clinical trial evidence supporting the use of the first-line medical options and the surgical treatments for classical idiopathic trigeminal neuralgia. There are RCTs supporting use of anticonvulsants such as carbamazepine and oxcarbazepine, which provide 50% pain relief in 70% of patients. Surgery can provide 100% pain relief with no further need for medication but there are no RCTs of microvascular decompression, potentially the most effective management, and other surgical procedures have been evaluated only in RCTs comparing techniques, and as such are very limited.
Comments on evidence
The most effective drugs are anticonvulsants, but design of drug trials is complicated because the gold-standard drug, carbamazepine, takes up to 3 weeks to be fully eliminated, and the disease is so severe that it is unethical to use a placebo. New designs are, therefore, needed and are being attempted. There are no randomised controlled trials comparing surgical options, and very few comparing technical variations of single techniques. The best surgical data are from prospective comparative cohort trials. Moreover, the disease can suddenly become extremely severe with longer-lasting bouts of pain, and there are no studies on how this should be managed. Given the difficulties inherent in conducting trials for both medical and surgical treatments, the evidence remains sparse, especially for the surgical therapies.
Search and appraisal summary
The update literature search for this review was carried out from the date of the last search, September 2007, to September 2013. For more information on the electronic databases searched and criteria applied during assessment of studies for potential relevance to the review, please see the Methods section. Searching of electronic databases retrieved 170 studies. After deduplication and removal of conference abstracts, 75 records were screened for inclusion in the review. Appraisal of titles and abstracts led to the exclusion of 54 studies and the further review of 21 full publications. Of the 21 full articles evaluated, two systematic reviews were added at this update. Based upon their own search, the contributors added two additional observational studies to the Comment section.
Ideally, patients benefit from surgical evaluation and counselling early in the disease process, so that appropriate contingency plans among varying surgical alternatives can be considered and decided upon before high-dose drug therapy interferes with cognition and memory, and before severe pain leads to time-urgent desperation. Acute severe attacks should be managed with lidocaine injections or infusions rather than opioids, which are ineffective.
Substantive changes at this update
Carbamazepine One systematic review added, which replaces an older systematic review. One retrospective cohort study was moved into the Comment section, as it no longer met our inclusion criteria. Categorisation unchanged (likely to be beneficial).
Lamotrigine One systematic review added, which replaces an older systematic review. Categorisation unchanged (unknown effectiveness).
Microvascular decompression New observational data added to Comment section. Categorisation unchanged (trade-off between benefits and harms [based on observational studies and/or consensus]).
Non-percutaneous destructive neurosurgical techniques (stereotactic radiosurgery) New observational data and systematic review added to the Comment section. Categorisation changed (from unknown effectiveness to trade off between benefits and harms [based on observational studies and/or consensus]).
Percutaneous destructive neurosurgical techniques (radiofrequency thermocoagulation, glycerol rhizolysis, or balloon compression) New observational data, systematic review, and RCTs added to Comment section. Categorisation changed (from unknown effectiveness to trade-off between benefits and harms [based on observational studies and/or consensus]).
INTRODUCTION: Trigeminal neuralgia is a sudden, unilateral, brief, stabbing, recurrent pain in the distribution of one or more branches of the fifth cranial nerve. Pain occurs in paroxysms, which can last from a few seconds to several minutes. The frequency of the paroxysms ranges from a few to hundreds of attacks a day. Periods of remission can last for months to years, but tend to shorten over time. The condition can impair activities of daily living and lead to depression. METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical question: What are the effects of ongoing treatments in people with trigeminal neuralgia? We searched: Medline, Embase, The Cochrane Library, and other important databases up to September 2013 (BMJ Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). RESULTS: We found seven studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. CONCLUSIONS: In this systematic review, we present information relating to the effectiveness and safety of the following interventions: baclofen; carbamazepine; gabapentin; lamotrigine; oxcarbazepine; microvascular decompression; and destructive neurosurgical techniques (radiofrequency thermocoagulation, glycerol rhizolysis, balloon compression, and stereotactic radiosurgery).