Occipital nerve blocks are an effective, safe, and well-tolerated therapy in patients with exacerbation of chronic or episodic cluster headache, according to two observational studies presented at the European Headache and Migraine Trust International Congress.

“It’s a treatment that can suppress attacks temporarily or reduce pain intensity in a high percentage of patients. From the clinical point of view, we gain 1 or 2 or 3 weeks of time to titrate up the standard medications so they can take effect. The patients are attack-free for some days, and they like that very much,” observed Dr. Charly Gaul of University Hospital in Essen, Germany.

Dr. Charly Gaul
At the congress, he presented a prospective study of occipital nerve blocks in 101 patients with intractable, disabling cluster headaches insufficiently controlled by the established preventive and acute medications. Sixty-one patients had episodic cluster headache; the other 40 had the less commonly encountered chronic cluster headache, characterized by multiple daily excruciating attacks with no or only brief remission periods.

All subjects received a single occipital nerve block (ONB) of the greater and lesser occipital nerve using 10 mg of triamcinolone along with bupivacaine 0.5% for local anesthesia. The patients completed a headache questionnaire prior to and again 3 and 10 days after receiving the ONB and then once more upon recurrence of their headache attacks.

A total of 83% of patients demonstrated a complete or partial response to their ONB. Efficacy was greater in the episodic cluster headache cohort: 41 of the 61 such patients became completely or temporarily attack free for a mean of 34 days, as did 20 of 40 patients with chronic cluster headache, for a notably briefer mean of 14 days.

Headache frequency in the episodic cluster headache group fell from a mean of 2.9 attacks/day at baseline to 0.7 attacks/day during the first 3 days following ONB and 1.1/day on days 7-10 post treatment. Self-reported pain intensity of attacks on a 0-10 scale improved from 8.4 at baseline to 2.3 in the first several days post-treatment and 3.3 on days 7-10 following the injection.

The average number of headaches per day in the chronic cluster headache cohort dropped from 3.3 at baseline to 1.1 during days 1-3 and 1.9 on days 7-10 post treatment. Pain intensity scores fell from a baseline of 7.9 to 3.9 shortly after ONB and 5.9 on days 7-10 post treatment, Dr. Gaul continued.

Adverse events (all minor) occurred in 11% of patients, the most common of which was a non–cluster headache, occurring in 3% of participants. Injection site pain and occipital muscle tension were among the other adverse events. No severe adverse events occurred.

Questions about ONB therapy that still remain to be answered in future controlled studies include the most efficient dose, the optimal number of injections, whether they should be administered uni- or bilaterally, and the type of steroids that work best. It seems that at present everyone working in this field is using a different injection concoction, the neurologist noted.

In a separate presentation at the congress, Dr. Norazah Abu Bakar of the National Hospital for Neurology and Neurosurgery, London, reported on 83 patients with chronic cluster headache treated with up to three unilateral ONB injections given at 3-month intervals at that institution.

The impetus for this retrospective study focusing on patients with refractory chronic cluster headache, she explained, was that while a recent noteworthy French randomized, double-blind, placebo-controlled clinical trial has shown ONB to be an effective therapy in patients with episodic cluster headache (Lancet Neurol. 2011;10:891-7), that study included only 15 patients with chronic cluster headache. Thus, few data are available on ONB in the 10% or so of cluster headache patients saddled with the extremely burdensome chronic cluster headache.

The ONB used in her study entailed a unilateral injection of a mixture of 80 mg of methylprednisolone and 2 mL of lidocaine 2%. Thirty of the 83 patients (36%) responded to a first injection with a complete pain-free interval lasting for a median of 14 days. Another 29 had partial pain relief, defined as greater than 50% improvement, lasting an average of 18 days. There were 19 nonresponders, and 5 patients experienced deterioration lasting for a median of 14 days.

Mean headache frequency in the overall group improved from 4.2 attacks/day at baseline to 1.7/day post treatment. Self-rated pain intensity went from a mean of 9.5 to 3.9 on a 10-point scale. And there was a further benefit: mean attack duration dropped from 108 minutes to 52 minutes.

The median latency period for a favorable response or headache worsening was 1 day after the injection. Patients reported no serious adverse events following treatment. One-third of subjects reported mild adverse events, mostly self-limited tenderness at the injection site, neck stiffness, and dizziness. No cutaneous atrophy or alopecia occurred after the injection.

Responders to the first injection were offered a second after 3 months, an interval chosen to minimize the risk of side effects due to overexposure to steroids. Among 45 patients treated a second time, 19 had a complete response and 16 a partial response with greater than 50% improvement. The median response duration was 18 days.

Three months later, 28 patients had a third ONB. Eleven showed a complete response and nine were partial responders, with a median response duration of 25 days.

Fourteen patients received a fourth injection, resulting in complete response in seven and partial response in three. The response duration averaged 23 days.

“Given the good tolerability profile when this simple procedure is performed every 3 months, occipital nerve blocks can play a useful role in the management of chronic cluster headache, allowing for periods of relief from an otherwise highly disabling disorder,” she concluded.

Cluster headache is a rare disorder characterized by attacks of unilateral pain, typically orbital, supraorbital, and/or temporal. The attacks generally last from 15 minutes to 3 hours. They occur with a frequency ranging from once every day or 2 up to eight per day. Episodic cluster headache occurs in skeins running for weeks to months, followed by remission periods that can last for months.

Dr. Gaul and Dr. Abu Bakar reported having no financial conflicts.