Expert consensus recommendations for the performance of peripheral nerve blocks for headaches--a narrative review.

Peripheral nerve blocks (PNBs) have long been employed in the treatment of various primary and secondary headache disorders (1), are increasingly used in general neurological practice (2) and may be utilized by up to 69% of practitioners with expertise in the treatment of headache disorders (3). The mechanism for PNBs in the treatment of headache disorders is not known. Clearly, the treatment effect is not based on a pure peripheral action. This principle is best demonstrated by the highest quality of evidence for PNBs in the treatment of cluster headache. A single (4,5) or repeated (6) injection with corticosteroid in the occipital or suboccipital region, targeting the greater occipital nerve (GON), derived largely from the C2 spinal level, effectively treats cluster headache, which is a trigeminal autonomic cephalalgia featuring pain in the ophthalmic division of the trigeminal nerve. In addition, pain relief from PNBs may not depend on the presence or duration of a pure local anesthetic effect (5), also evident by their reduction in allodynia contralateral to the side of injection (7) as well as photophobia (8). Presumably, GON blocks and other PNBs reduce nociceptive input into the trigeminocervical complex and lead to central descending inhibitory, secondary effects (8) in aborting an acute headache attack or shortening an acute cluster period. There is a wealth of clinical experience and a heterogeneous evidence base suggesting PNBs as a safe and effective therapy in headache medicine, particularly cluster headache (1,3,9). However, for migraine the evidence is less certain (1,9), most notably featuring a single randomized controlled comparative trial that assessed the benefit of a corticosteroid added to a local anesthetic agent in patients with transformed migraine (10). In this issue of Cephalalgia, Dilli and colleagues fill this gap, addressing GON blockade with corticosteroid for the treatment of migraine in a randomized, doubleblind, placebo-controlled trial (11). They included patients at a single center, 18–75 years of age with episodic or chronic migraine who had at least one weekly attack but without continuous headache, recent initiation of evidence-based prophylaxis, frequent opioid use, substance abuse, allergy to injection ingredients, major psychiatric disorder or other contemporaneous headache disorders. Patients were randomized to injections in the GON region with either the active therapy: 2.5ml 0.5% bupivacaine plus 0.5ml 20mg methylprednisolone or what they termed their placebo: 2.75ml normal saline plus 0.25ml 1% lidocaine without epinephrine. Injections were performed unilaterally or bilaterally, depending on the location of the patient’s head pain. Various baseline predictive data points were captured that are novel in this setting, including pain directionality and graded GON region tenderness. Prospective diary completion in the 4 weeks before and after GON blockade was another major strength. Reasonably based on their clinical experience, the primary endpoint was defined as a 50% or more reduction in the frequency of moderate or severe headache days in the active versus placebo group at 4 weeks compared to a 4 week preinjection baseline period. Ultimately the authors analyzed 33 patients in the active group and 30 patients in the placebo group, who were mostly women, usually featured an occipital location of head pain and had a mean baseline headache frequency of 13 days during the 4-week baseline period. Over 75% of patients in both groups received bilateral injections. The study failed to meet its primary endpoint, as the 50% reduction in the frequency of moderate or severe migraine headache days at 4 weeks was 30% for both groups. The study also failed to meet any secondary

To review the existing literature and describe a standardized methodology by expert consensus for the performance of trigger point injections (TPIs) in the treatment of headache disorders. Despite their widespread use, the efficacy, safety, and methodology of TPIs have not been reviewed specifically for headache disorders by expert consensus. The Peripheral Nerve Blocks and Other Interventional Procedures Special Interest Section of the American Headache Society over a series of meetings reached a consensus for nomenclature, indications, contraindications, precautions, procedural details, outcomes, and adverse effects for the use of TPIs for headache disorders. A subcommittee of the Section also reviewed the literature. Indications for TPIs may include many types of episodic and chronic primary and secondary headache disorders, with the presence of active trigger points (TPs) on physical examination. Contraindications may include infection, a local open skull defect, or an anesthetic allergy, and precautions are necessary in the setting of anticoagulant use, pregnancy, and obesity with unclear anatomical landmarks. The most common muscles selected for TPIs include the trapezius, sternocleidomastoid, and temporalis, with bupivacaine and lidocaine the agents used most frequently. Adverse effects are typically mild with careful patient and procedural selection, though pneumothorax and other serious adverse events have been infrequently reported. When performed in the appropriate setting and with the proper expertise, TPIs seem to have a role in the adjunctive treatment of the most common headache disorders. We hope our effort to characterize the methodology of TPIs by expert opinion in the context of published data motivates the performance of evidence-based and standardized treatment protocols.

Headaches in children and adolescents are common, causing debilitating symptoms in many. Treatment of headache disorders can be complex and standard lifestyle changes as well as oral medications may offer inadequate relief. The purpose of this article is to review the mechanism of action, efficacy and technique of peripheral nerve blocks (PNBs) and the role they play in treating paediatric headache disorders. Evidence for the use of PNBs in youth is limited. However, available studies show evidence of benefit in both primary and secondary headache disorders. Variability exists in the type of block, medication choice, volume infused and frequency of this treatment. There are no serious side effects associated with PNBs. PNBs are well tolerated and effective as adjunctive therapy for many disabling paediatric headache disorders. The technique can be easily learned by frontline and specialty practitioners. Prospective placebo-controlled studies are needed to determine how to best maximize PNBs for headache management (i.e. medication choice, timing and so on).

The article by) Bigeleisen1is a nice illustration of gross anatomical changes that may occur in a nerve during performance of a peripheral nerve block (PNB) and highlights the emerging role of ultrasound in the performance of PNB. The author used a 10-MHz linear transducer to demonstrate the findings. Transducers with higher frequencies are now becoming increasingly available and will in the future provide better definition of the anatomic details, particularly when superficial nerves are imaged.However, we have a few comments. (1) In this study, patients were sedated with 1–2 mg midazolam and 50–100 μg fentanyl, which may have interfered with the ability to report paresthesia during performance of the PNB. Because the nerves were identified by the report of paresthesia by the subject or the feeling of a pop, one would like to know the distribution of the techniques in identifying the nerves. (2) The title is misleading. Although the author uses the phrase “ultrasound-guided axillary block” in the title, according to the methods, the actual nerve was identified (according to the author) only “when a paresthesia was elicited or a pop was felt.” The author does not report the plane at which the needle was advanced in relation to the ultrasound beam in the methods section. If the needle was advanced perpendicular to the beam at any time, it might have been difficult to comment on whether the needle entered the substance of the nerve. (3) No age range of patients was reported in the results section.We do agree with the author that intraneural injection may not always lead to nerve injury. We work in a tertiary care pediatric center and perform almost all of our PNBs during general anesthesia. Most of our PNB are increasingly being performed with ultrasound guidance in conjunction with a nerve stimulator. We would like to report a case where a left femoral nerve block was performed during general anesthesia for postoperative analgesia in a 12-yr-old, 33-kg girl who underwent a left distal femoral and proximal tibial epiphysiodesis. The femoral nerve block was performed using a nerve stimulator with ultrasound guidance. Thirty milliliters ropivacaine, 0.1%, was injected in increments without resistance via a 22-gauge Braun Stimuplex needle (B. Braun Medical, Bethlehem, PA) at a stimulation threshold of 0.31 mA. Postoperatively, the patient had complete sensory blockade in the distribution of the left femoral and lateral cutaneous nerve of the thigh and did not need any opioids for 23 h. The patient had no residual numbness (after 24 h), paresthesia, or dysesthesia. A review of the ultrasound images obtained during the block showed swelling of the nerve after injection of the local anesthetic (figs. 1A and B, similar to the images obtained by Bigeleisen.1As reported by Bigeleisen,1the occurrence of intraneural injection during PNB is probably not uncommon, and only a larger series can determine the consequences of intraneural injection noted on ultrasound.*The Children’s Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania. ganesha@email.chop.edu

Background Peripheral nerve block (PNB) is usually performed in patients with migraine who are resistant to treatment with medications.Objective To compare the efficacy of PNB alone and PNB combined with prophylactic medications in migraine patients.Method The data on migraine patients who underwent PNB in our clinic between November 2019 and January 2022 were retrospectively reviewed. Blocks of the greater occipital nerve (GON), lesser occipital nerve (LON) and supraorbital nerve (SON) were performed upon admission and in the second week.Results The study included 116 patients. While 21 out of 39 episodic migraine (EM) patients continued to use prophylactic medications, 18 were followed up with PNB alone. While 49 out of 77 chronic migraine (CM) patients continued to use prophylactic medications, 28 were followed up with PNB alone. Comparison of the admission and second-month data of the patients who only underwent PNB and those who continued the drug treatment together with PNB in both the EM and the CM group showed that the number of days with pain, number of analgesics taken and scores on the Visual Analog Scale (VAS) and the Migraine Disability Assessment (MIDAS) were significantly reduced in both groups (p < 0.01). Comparison of the second-month data of the patients followed up with PNB alone and those followed up with PNB together with prophylactic medications showed that there was no significant difference between the EM and CM patients (p > 0.05).Conclusion Bilateral GON, LON and SON block with lidocaine injection seems to be an effective treatment on its own, without the need for prophylactic medications, in both EM and CM patients during a two-month follow-up.

To provide an overview of the current available literature on peripheral nerve blocks for the management of migraine and other headache disorders in adults. Peripheral nerve blocks have been commonly performed in the headache practice for migraine, cluster headache, occipital neuralgia, and other headache disorders, despite a paucity of evidence supporting their use historically. In the past decade, there has been an effort to explore the efficacy and safety of peripheral nerve blocks for the management of headache, with the greatest interest centered around greater occipital blocks. We performed a search in PubMed using key words including "occipital nerve blocks," "peripheral nerve blocks," "occipital nerve," "migraine," "cluster headache," and "neuralgia." We reviewed the randomized controlled trials (RCTs), observational studies, and case series, and summarized the anatomy, techniques, and the evidence for the use of peripheral nerve blocks in different headache disorders, with particular focus on available RCTs. Case reports were included for a detail review of adverse events. Of 12 RCTs examining the use of greater occipital nerve blocks for migraine, all but one demonstrate efficacy with reduction in headache frequency, intensity, and/or duration compared to placebo. Studies have not demonstrated a difference in clinical outcomes with the use of corticosteroids for nerve blocks compared to blocks with local anesthetic in the treatment of migraine. There are two RCTs supporting the use of greater occipital blockade for cluster headache, both showing benefit of suboccipitally injected corticosteroid. One RCT suggests benefit of greater occipital nerve blocks for cervicogenic headache. Observational studies and case series/reports show that greater occipital nerve block may be effective in prolonged migraine aura, status migrainosus, post-dural puncture headache, and occipital neuralgia. Overall, peripheral nerve blocks are well tolerated. Serious side effects are rare but have been reported, including acute cerebellar syndrome and infection. Peripheral nerve blocks, especially occipital nerve blocks, are a viable treatment option for migraine and may be helpful in cluster headache as a transitional therapy or rescue therapy. Additional prospective studies are needed to investigate the efficacy and safety of occipital nerve blocks for long-term migraine prevention, as well as for other headache disorders, such as occipital neuralgia.

Headache is a common neurological referral and a frequent cause for acute hospital admissions. Despite peripheral nerve blocks being widely used in headache and pain services to treat patients with...

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.

Headache is prevalent, disabling, and a frequent neurological referral in the healthcare system. Clinic-based procedures have evolved in recent years to play an important role in headache medicine, with growing evidence on the safety, tolerability and efficacy of peripheral nerve blocks (PNBs). Despite novel headache therapies, PNBs are still widely used in headache services to treat primary and secondary headache disorders, including cluster headache and other trigemino-autonomic cephalalgias, migraine, occipital neuralgia, and other less frequent headache disorders. We aim to provide an update of the current evidence and a practical approach for delivering the most common PNBs used in clinical practice. We aim to describe PNBs indications, contraindications, injection locations and techniques, drug constituents, and potential pitfalls.

Development of a standardized peripheral nerve block procedure note form

Headache disorders are common and disabling, and many therapies that are effective and safe are procedural. After pivotal clinical trials, onabotulinumtoxinA has become an established preventive therapy for chronic migraine; it is better tolerated than many other treatments and may be useful for other headache disorders. Peripheral nerve blocks, especially greater occipital nerve blocks, have amassed evidence from randomized trials in the acute and short-term preventive treatment of migraine and cluster headache. Trigger point injections and sphenopalatine ganglion blocks have recent trials suggesting efficacy and safety in properly selected patients. Medical education initiatives are needed to train neurologists in these procedures to help manage the large population of patients with headache disorders who need them. Evidence exists for the efficacy and safety of procedural therapies to be incorporated into neurology practice for the management of patients with migraine, cluster headache, and other headache disorders.

Diagnosis and Treatment of Headache in the Ambulatory Care Setting: A Review of Classic Presentations and New Considerations in Diagnosis and Management

Background:Regional analgesia is widely used for total knee replacement surgeries (TKR) as it has lesser side-effects and better analgesic efficacy when compared with traditional oral analgesics. Peripheral nerve blockade has also been utilized, including continuous infusion techniques. With the use of ultrasound, the needle and catheter placement can be done accurately under real-time guidance. This may prove a more suitable approach compared with the epidural technique.Aims:Post-operative analgesia in TKR patients was compared between continuous epidural analgesia (CEA) and continuous femoral block (CFB) techniques. VAS scores and use of rescue analgesic were used as parameters. Secondary aims included comparison of rehabilitation scores and side-effects in the form hypotension, vomiting, itching and urinary retention.Settings and Design:Randomised, controlled, non-blinded study done in a tertiary care private hospital.Methods:Forty-two patients fulfilling the study criteria were randomised into the CEA and CFB groups. In total, four patients: three in the CFB group and one in the CEA group, were excluded because of catheter migration.Statistical Analysis:Mean VAS score at 6, 6–24, 24–48 and 48–72 h were considered. Significance was assessed at the 5% level.Results and Conclusion:VAS scores were significantly high (P=0.001) in the femoral group at 6 h, after which there was a declining trend, and scores were essentially similar from 24 h. Common side-effects were more common in the CEA group. Our study shows that CFB gives equivalent analgesia compared with CEA in TKR patients with clinically meaningful decrease in side-effects.

Ultrasound as the only nerve localization technique for peripheral nerve block

Peripheral nerve block in patients with Ehlers-Danlos syndrome, hypermobility type: a case series