Objective To describe a standardized methodology for the performance of peripheral nerve blocks (PNBs) in the treatment of headache disorders. Background PNBs have long been employed in the management of headache disorders, but a wide variety of techniques are utilized in literature reports and clinical practice. Methods The American Headache Society Special Interest Section for PNBs and other Interventional Procedures convened meetings during 2010‐2011 featuring formal discussions and agreements about the procedural details for occipital and trigeminal PNBs. A subcommittee then generated a narrative review detailing the methodology. Results PNB indications may include select primary headache disorders, secondary headache disorders, and cranial neuralgias. Special procedural considerations may be necessary in certain patient populations, including pregnancy, the elderly, anesthetic allergy, prior vasovagal attacks, an open skull defect, antiplatelet/anticoagulant use, and cosmetic concerns. PNBs described include greater occipital, lesser occipital, supratrochlear, supraorbital, and auriculotemporal injections. Technical success of the PNB should result in cutaneous anesthesia. Targeted clinical outcomes depend on the indication, and include relief of an acute headache attack, terminating a headache cycle, and transitioning out of a medication‐overuse pattern. Reinjection frequency is variable, depending on the indications and agents used, and the addition of corticosteroids may be most appropriate when treating cluster headache. Conclusions These recommendations from the American Headache Society Special Interest Section for PNBs and other Interventional Procedures members for PNB methodology in headache disorder treatment are derived from the available literature and expert consensus. With the exception of cluster headache, there is a paucity of evidence, and further research may result in the revision of these recommendations to improve the outcome and safety of these interventions.

The reliability of the questionnaire as a diagnostic tool of allodynia varies with the proportion of allodynic patients in a given clinic. The major source of variability is the misconception of nonallodynic patients that their skin is hypersensitive during migraine.

Adding triamcinolone to local anaesthetics when performing GONB and TPIs was not associated with improved outcome in this sample of patients with TM.

The sphenopalatine ganglion (SPG) has attracted the interest of practitioners treating head and face pain for over a century because of its anatomical connections and role in the trigemino-autonomic reflex. In this review, we discuss the anatomy of the SPG, as well as what is known about its role in the pathophysiology of headache disorders, including cluster headache and migraine. We then address various therapies that target the SPG, including intranasal medication delivery, new SPG blocking catheter devices, neurostimulation, chemical neurolysis, and ablation procedures.

Objective.—To evaluate the effect of GONB, with or without trigger point injection (TPI), on dynamic mechanical (brush) allodynia (BA) and on head pain in migraine. Background.—Patients with migraine often have cutaneous allodynia that is related to sensitization of central pain neurons. Greater occipital nerve block (GONB) is an effective treatment for migraine headache; however, its effect on cutaneous allodynia in migraine is unknown. Methods.—We studied patients with migraine and BA who were treated with GONB with or without TPI. Demographic data, migraine history, and headache features were documented. Allodynia was evaluated using a structured questionnaire and by applying a 4 × 4‐inch gauze pad to skin areas in the trigeminal and cervical dermatomes. Degree of allodynia (the allodynia score) was measured on a 100‐mm visual analog scale (VAS) before treatment and 10 and 20 minutes thereafter. Headache levels were assessed using an 11‐point verbal scale. Allodynia scores, as well as headache levels, before and after treatment were compared. Results.—Nineteen patients were studied. Mean age was 43.6 ± 11.8 years. Twenty minutes after treatment, headache was reduced in 17 patients (89.5%) and did not change in 2 (10.5%). The average headache level was 6.53 before treatment and 3.47, 20 minutes after it. The average allodynia score decreased after 20 minutes in all patients. Average allodynia score per site was reduced by 18.69 mm and 13.74 mm in the trigeminal and cervical areas, respectively. There was a positive correlation between allodynia index, obtained through the questionnaire, and allodynia score, obtained by examination. Conclusion.—GONB, with or without TPI, reduced both head pain and brush allodynia in this migraine patient group.

Allodynia has been described in migraine but has not been fully investigated for the different sensory modalities. The aim of this study was to compare the prevalence of dynamic (brush) and static (pressure) mechanical allodynia in migraine patients and to suggest a practical method of testing them in a clinical setting. Patients with International Headache Society-defined episodic migraine (EM) or with transformed migraine (TM) as defined by Silberstein and Lipton were prospectively recruited from the Jefferson Headache Center out-patient clinic. A questionnaire of migraine features and symptoms of allodynia was administered. Brush allodynia (BA) was tested by cutaneous stimulation with a gauze pad and pressure allodynia (PA) was tested using von Frey hairs (VFH). The prevalence of BA and PA in all patients and in the different subgroups was calculated and correlated with migraine features. We recruited 55 migraine patients. Twenty-five had EM and 30 had TM. BA was present in 18 (32.7±) patients and PA in 18–24 (32.7–43.6±). Allodynia to both brush and pressure was found in 13–17 (23.6–30.9±) patients. If a patient had allodynia to one modality only, it was more likely to be PA than BA. Both BA and PA were more common in patients with TM compared with those with EM [BA 46.7± vs. 16.0±; PA (differences significant for the medium and thick VFHs) 50± vs. 20± and 50± vs. 12±, respectively]. Both types of allodynia were also more common in patients with migraine with aura compared with those with migraine without aura (BA 57.1± vs. 17.6±; PA 57.1–61.9± vs. 17.6–32.7±). There was a positive correlation between allodynia score (as obtained by examination) and allodynia index (as obtained by history) for both BA and PA. The incomplete, although considerable, overlap between BA and PA suggests that allodynia to different sensory modalities is associated with sensitization of different neuronal populations. Because PA was more common than BA, it may be a more sensitive indicator of allodynia in migraine. PA can be tested clinically in a practical and systematic manner.

Interventional procedures such as peripheral nerve blocks (PNBs) and trigger point injections (TPIs) have long been used in the treatment of various headache disorders. There are, however, little data on their efficacy for the treatment of specific headache syndromes. Moreover, there is no widely accepted agreement among headache specialists as to the optimal technique of injection, type, and doses of the local anesthetics used, and injection regimens. The role of corticosteroids in this setting is also debated. We performed a PubMed search of the literature to find studies on PNBs and TPIs for headache treatment. We classified the abstracted studies based on the procedure performed and the treated condition. We found few controlled studies on the efficacy of PNBs for headaches, and virtually none on the use of TPIs for this indication. The most widely examined procedure in this setting was greater occipital nerve block, with the majority of studies being small and non-controlled. The techniques, as well as the type and doses of local anesthetics used for nerve blockade, varied greatly among studies. The specific conditions treated also varied, and included both primary (eg, migraine, cluster headache) and secondary (eg, cervicogenic, posttraumatic) headache disorders. Trigeminal (eg, supraorbital) nerve blocks were used in few studies. Results were generally positive, but should be taken with reservation given the methodological limitations of the available studies. The procedures were generally well tolerated. Evidently, there is a need to perform more rigorous clinical trials to clarify the role of PNBs and TPIs in the management of various headache disorders, and to aim at standardizing the techniques used for the various procedures in this setting.

Using quantitative sensory testing (QST), we found that many migraineurs seeking secondary and tertiary care exhibit cutaneous allodynia whenever they undergo a migraine attack, but not interictally (i.e. between attacks). When such patients were questionned interictally in the clinic about symptoms of skin sensitivity in past attacks, 76% of them were 'correctly' classified either as allodynic (>or=1 symptom) or non-allodynic (zero symptoms) in line with the QST analysis. In this study, patients were classified as allodynic if they documented any one symptom of allodynia during an actual migraine attack which they had already cited in an earlier interictal interview. Of a total of 151 patients, 77% were classified as allodynic, citing on average four symptoms of skin hypersensitivity, three of which were consistently cited in the interictal interview and again during an attack. Among the remaining 23% of patients who were classified as non-allodynic, half cited zero symptoms as expected, while the other half cited between one and five symptoms, each of which was cited either interictally or during an attack, but not in both. Further analysis showed that 97% of patients citing two or more symptoms during an attack consisted of the patients labelled as allodynic, and that 75% of those citing just one symptom during an attack consisted of patients labelled as non-allodynic. Short of QST analysis, the results suggest that about 90% of all patients can be identified as allodynic or non-allodynic depending on whether or not they (i) consistently cited the same item(s) both interictally and during an attack or, alternatively, (ii) cited two or more symptoms during an attack.