Occipital nerve blocks: effect of symptomatic medication: overuse and headache type on failure rate.

OBJECTIVE

To explore the effect of symptomatic medication overuse (SMO) and headache type on occipital nerve block (ONB) efficacy.

METHODS

We conducted a chart review of all of the ONBs performed in our clinic over a 2-year period.

RESULTS

Of 108 ONBs with follow-up data, ONB failed in 22% of injections overall. Of the other 78%, the mean decrease in head pain was 83%, and the benefit lasted a mean of 6.6 weeks. Failure rate without SMO was 16% overall, and with SMO was 44% overall (P < .000). In those who did respond, overall magnitude and duration of response did not differ between those with and those without SMO. Without SMO, ONB failure rate was 0% for postconcussive syndrome, 14% for occipital neuralgia, 11% for non-intractable migraine, and 39% for intractable migraine. With SMO, failure rate increased by 24% (P = .14) in occipital neuralgia, by 36% (P = .08) for all migraine, and by 52% (P = .04) for non-intractable migraine.

CONCLUSIONS

SMO tripled the risk of ONB failure, possibly because medication overuse headache does not respond to ONB. SMO increased ONB failure rate more in migraineurs than in those with occipital neuralgia, possibly because migraineurs are particularly susceptible to medication overuse headache. This effect was much more pronounced in non-intractable migraineurs than in intractable migraineurs.