NERVE BLOCKS & NEUROSTIMULATION in the management of headaches

Available preventive drug treatments have only partial efficacy in primary headaches and most of them cause unpleasant side effects. Moreover, the chronic forms, the most disabling ones, become notoriously resistant to prophylactic pharmacotherapy. Alternative therapies have thus been developed. Nerve blocks, for instance, are used since a long term, but RCTs of their efficacy are scarce. Suboccipital infiltrations are the most useful. They consist of an injection in the vicinity of the greater occipital nerve of a steroid and a local anaesthetic. Various steroids have been used, but the best results seem to be obtained with mixtures of shortand long-acting compounds. In most studies, an injection of only a local anaesthetic has no, or a very transient, effect. In cluster headache (CH), for instance, several studies have shown that a suboccipital steroid-lidocaïne infiltration is clearly superior to placebo, exceeding a 70% efficacy rate, both in the episodic and the chronic form of the disorder. Side effects are minor and transient, but focal alopecia, reported only with superficial injections, should be avoided by injecting into deep structures. Suboccipital infiltrations are also efficient in other trigeminal autonomic cephalalgias, hemicranias continua, fixed unilateral migraine, cervicogenic headache and occipital neuralgia. In refractory CH alcohol or steroid infiltrations of the spheno-palatine ganglion may also be useful, but the effect seems to be transient and there no placebo-controlled trials.