Morphological features of the greater occipital nerve and its possible importance for interventional procedures.

Being one of the most prevalent neurological symptoms, headaches are burdensome and costly. Blocks and decompression surgeries of the greater occipital nerve (GON) have been frequently used for migraine, cervicogenic headache, and occipital neuralgia which are classified under headache by International Headache Society. Knowledge of complex anatomy of GON is crucial for its decompression surgery and block. This study was performed to elucidate anatomical features of this nerve in detail. Forty-one cadavers were dissected bilaterally. According to its morphological features, GON was classified into four main types that included 18 subtypes. Moreover, potential compression points of the nerve were defined. The number of branches of the GON up to semispinalis capitis muscle and the number of its branches that were sent to this muscle were recorded. The most common variant was that the GON pierced the aponeurosis of the trapezius muscle, curved around the lower edge of the obliquus capitis inferior muscle, and was loosely attached to the obliquus capitis inferior muscle (Type 2; 61 sides, 74.4%). In the subtypes, the most common form was Type 2-A (44 sides, 53.6%), in which the GON pierced the aponeurosis of each of the trapezius muscle and fibers of semispinalis muscle at one point and there was a single crossing of the GON and occipital artery. Six potential compression points of the GON were detected. The first point was where the nerve crossed the lower border of the obliquus capitis inferior muscle. The second and third points were at its piercing of the semispinalis capitis muscle and the muscle fibers/aponeurosis of the trapezius, respectively. Fourth, fifth, and sixth compression points of GON were located where the GON and occipital artery crossed each other for the first, second, and third times, respectively. On 69 sides, 1-4 branches of the GON up to the semispinalis capitis muscle were observed (median = 1), while 1-4 branches of GON were sent to the semispinalis capitis muscle on 67 sides (median = 1). The novel anatomical findings described in this study may play a significant role in increasing the success rate of invasive interventions related with the GON.

ANODYNE study: A double-blind randomized trial of greater occipital nerve block of methylprednisolone and lignocaine versus placebo as a transitional preventive treatment for episodic cluster headache.

BACKGROUND: There is inadequate evidence of the efficacy of greater occipital nerve block (GONB) for the preventive treatment of cluster headaches. We assessed the efficacy and tolerability of GONB injections as a transitional preventive treatment for episodic cluster headaches (ECH). METHODS: This randomized, double-blind, placebo-controlled, parallel-group trial conducted at GB Pant Institute of Postgraduate Medical Education and Research, New Delhi, India, included ECH patients diagnosed by ICHD-3 criteria, aged 18-65, with one or more attacks per 24 h for seven days before randomization (baseline). ECH patients were either not on preventive medications or on stable doses for at least three months. ECH patients were randomized to receive active GONB (2 ml methylprednisolone (80 mg) and 2 ml lignocaine (2%)) and placebo (4 ml saline injections). Before giving GONB, lignocaine jelly was applied topically to mask the effect of numbness following the GONB. The primary efficacy endpoint was the mean change in weekly attack frequency from baseline to Week 4. Efficacy analyses were performed in a modified intention-to-treat population that included all patients who received at least one injection of GONB and had a follow-up for one week following GONB. The safety analysis included treatment-emergent adverse effects (TEAE) in all patients who received at least one dose of investigational product. The trial was registered with the Clinical Trials Registry of India (CTRI/2021/21/038397). RESULTS: Forty ECH patients were randomized between December 2021 and January 2023. Thirty-nine patients (19 in the active and 20 in the placebo groups) were available for efficacy analysis. The change in weekly attack frequency from baseline to Week 4 was -11.1 (95% CI: -8.5 to -4.4) for the active group compared to -7.7 (95% CI: -11.8 to -9.8) for placebo (mean difference -3.4 (95% CI: -5.2 to -1.7, p < 0.001). We noted TEAE in 18 (90%) of 20 patients who received the active drug and in 18 (90%) of 20 patients who received a placebo (p = 0.38). The common TEAE were local site bleeding and pain, which were mild and transient. No serious adverse events were reported. CONCLUSION: This study found that GONB with methylprednisolone and lignocaine significantly reduced the weekly attack frequency from baseline to Week 1 through Week 4 in ECH patients compared to a placebo. GONB was well tolerated.

Assessing the effectiveness of greater occipital nerve block in chronic migraine: a systematic review and meta-analysis.

BACKGROUND & AIMS: Chronic migraine poses a global health burden, particularly affecting young women, and has substantial societal implications. This study aimed to assess the efficacy of Greater Occipital Nerve Block (GONB) in individuals with chronic migraine, focusing on the impact of local anesthetics compared with placebo. METHODS: A meta-analysis and systematic review were conducted following the PRISMA principles and Cochrane Collaboration methods. Eligible studies included case-control, cohort, and randomized control trials in adults with chronic migraine, adhering to the International Classification of Headache Disorders, third edition (ICHD3). Primary efficacy outcomes included headache frequency, duration, and intensity along with safety assessments. RESULTS: Literature searches across multiple databases yielded eight studies for qualitative analysis, with five included in the final quantitative analysis. A remarkable reduction in headache intensity and frequency during the first and second months of treatment with GONB using local anesthetics compared to placebo has been reported. The incidence of adverse events did not differ significantly between the intervention and placebo groups. CONCLUSION: The analysis emphasized the safety and efficacy of GONB, albeit with a cautious interpretation due to the limited number of studies and relatively small sample size. This study advocates for further research exploring various drugs, frequencies, and treatment plans to enhance the robustness and applicability of GONB for chronic migraine management.

Review of craniofacial pain syndromes involving the greater occipital nerve: relevant anatomy, clinical findings, and interventional management.

Craniofacial pain syndromes exhibit a high prevalence in the general population, with a subset of patients developing chronic pain that significantly impacts their quality of life and results in substantial disabilities. Anatomical and functional assessments of the greater occipital nerve (GON) have unveiled its implication in numerous craniofacial pain syndromes, notably through the trigeminal-cervical convergence complex. The pathophysiological involvement of the greater occipital nerve in craniofacial pain syndromes, coupled with its accessibility, designates it as the primary target for various interventional procedures in managing craniofacial pain syndromes. This educational review aims to describe multiple craniofacial pain syndromes, elucidate the role of GON in their pathophysiology, detail the relevant anatomy of the greater occipital nerve (including specific intervention sites), highlight the role of imaging in diagnosing craniofacial pain syndromes, and discuss various interventional procedures such as nerve infiltration, ablation, neuromodulation techniques, and surgeries. Imaging is essential in managing these patients, whether for diagnostic or therapeutic purposes. The utilization of image guidance has demonstrated an enhancement in reproducibility, as well as technical and clinical outcomes of interventional procedures. Studies have shown that interventional management of craniofacial pain is effective in treating occipital neuralgia, cervicogenic headaches, cluster headaches, trigeminal neuralgia, and chronic migraines, with a reported efficacy of 60-90% over a duration of 1-9 months. Repeated infiltrations, neuromodulation, or ablation may prove effective in selected cases. Therefore, reassessment of treatment response and efficacy during follow-up is imperative to guide further management and explore alternative treatment options. Optimal utilization of imaging, interventional techniques, and a multidisciplinary team, including radiologists, will ensure maximum benefit for these patients.

Trans-obliquus inferior capitis course of the greater occipital nerve: A potential cause of occipital neuralgia?

Occipital neuralgia can be due to multiple etiologies. One of these is potential compression of the greater occipital nerve (GON). In this regard, one relationship of the GON, its course through the obliquus inferior capitis muscle (OIC), has yet to be well studied. Therefore, the current anatomical study was performed to elucidate this relationship better. In the prone position, the suboccipital triangle was exposed, and the relationship between the GON and OIC was documented in 72 adult cadavers (144 sides). The GON was found to pierce the OIC on four sides (2.8%), unilaterally in two cadavers and bilaterally in one cadaver. Two cadavers were male, and one was female. Histological samples were taken from GONs with a normal course around the OIC, and nerves were found to pierce the OIC. The GON of all four sides identified histological changes consistent with nerve potential compression (e.g., epineurial and perineurial thickening). This is also the first histological analysis of the trans-OIC course of the GON, demonstrating signs of chronic nerve potential compression. Although uncommon, entrapment of the GON by the OIC may be an underrecognized etiology of occipital neuralgia.

3D anatomy of the supraorbital and greater occipital nerve trajectories.

PURPOSE: This research aims to enhance understanding of the anatomy of the supraorbital nerve (SON) and greater occipital nerve (GON), focusing on their exit points, distal trajectories, and variability, utilizing a novel 3D representation. METHODS: Ten cadaveric specimens underwent meticulous dissection, and 3D landmarks were registered. Models were generated from CT scans, and a custom 3D method was employed to visualize nerve trajectories. Measurements, including lengths and distances, were obtained for the SON and GON. RESULTS: The SON exhibited varied exit points, with the lateral branches being the longest. The GON showed distinct branching patterns, which are described relative to various anatomical reference points and planes. No systematic left-right differences were observed for either nerve. 3D analysis revealed significant interindividual variability in nerve trajectories. The closest approximation between the SON and GON occurred between lateral branches. CONCLUSION: The study introduces a novel 3D methodology for analyzing the SON and GON, highlighting considerable anatomical variation. Understanding this variability is crucial for clinical applications and tools targeting the skull innervation. The findings serve as a valuable reference for future research, emphasizing the necessity for personalized approaches in innervation-related interventions.

The triangular area between the greater, lesser, and third occipital nerves and its possible clinical significance.

PURPOSE: Occipital Neuralgia (ON) is defined as a unilateral or bilateral pain in the posterior area of the scalp occurring in the distribution area or areas of the greater occipital nerve (GON), lesser occipital nerve (LON), and/or third occipital nerve (TON). In the present study, the purpose was to show the possible importance of the triangular area (TA) in nerve block applied in ON by measuring the TA between GON, TON, and LON. METHODS: A total of 24 cadavers (14 males, 10 females) were used in the present study. The suboccipital region was dissected, revealing the points where the GON and TON pierced the trapezius muscle and superficial area, and the point where the LON left the sternocleidomastoid muscle from its posterior edge and was photographed. The area of the triangle between the superficial points of these three nerves and the center of gravity of the triangle (CGT) were determined by using the Image J Software and the results were analyzed statistically. RESULTS: The mean TA values were 952.82 ± 313.36 mm2 and 667.55 ± 273.82 mm2, respectively in male and female cadavers. Although no statistically significant differences were detected between the sides (p > 0.05), a statistically significant difference was detected between the genders (p < 0.05). The mean CGT value was located approximately 5 cm below and 3-3.5 cm laterally from the external occipital protuberance in both genders and sides. CONCLUSION: In ON that has more than one occipital nerve involvement, all occipital nerves can be blocked by targeting TA with a single occipital nerve block, and thus, the side effects that may arise from additional blocks can be reduced. The fact that there was a statistically significant difference according to the genders in the TA suggests that different block amounts can be applied according to gender.

Comparison of the clinical efficacy of ultrasound-guided GON blockade using low and high concentrations of bupivacaine in chronic migraine.

Background/aim: In this study, it was aimed to retrospectively compare the effect of greater occipital nerve (GON) block performed with ultrasonography using low (0.3%) and high (0.5%) concentrations of bupivacaine on pain scores and patient satisfaction in chronic migraine (CM). Materials and methods: The mean number of days with pain, the mean duration of pain in the attacks, and the highest numerical rating scale (NRS) scores recorded in the 1 month preblock and 1 and 3 months postblock of 80 patients (40 for Group 1, 0.3% bupivacaine; 40 for Group 2, 0.5% bupivacaine) who underwent ultrasonography-guided GON block were recorded from the patient file data. According to the protocol applied by our clinic, GON block was applied to each patient 6 times with the same procedures, in total. Results: While there was a statistically significant difference between the groups in terms of the number of days with pain and the maximum NRS score in the 1-month preblock evaluation (p = 0.01, p < 0.001), at 3 months postblock, no statistical difference was observed in terms of the number of days with pain, duration of pain, or NRS score (p = 0.961, p = 0.108, and p = 0.567). In the intragroup evaluations, at 3 months postblock, the number of days with pain decreased from 17.5 days to 7 days in Group 1 and from 24.0 days to 8.0 days in Group 2. The duration of pain and maximum NRS values were statistically significantly decreased in the intragroup evaluation in both groups pre and postblock. Conclusion: Complications arising from the procedure and the local anesthetic used are essential points to consider in applying GON block. In CM treatment using GON block application, a similar effect to the standard local anesthetic application (0.5%) can be achieved by administering local anesthetic at a lower dose (0.3%).

The effect of anesthetic blockade of greater occipital nerve during the withdrawal period of the medication overuse headache treatment.

Background and purpose:

Discontinua­tion of medication still remains a key element in the treatment of medication overuse headache (MOH), but there is no consensus on the withdrawal procedure. We aimed to share the promising results of anesthetic blockade of greater occipital nerve (GON), which can be an alternative to existing treatments during the early withdrawal period of MOH treatment.

This study was conducted using regular electronic medical records and headache diaries of patients diagnosed with MOH and treated with anesthetic GON blockade with 0.5% bupivacaine solution in a specia­lized headache outpatient clinic. A total of 86 patients who developed MOH while being followed up for chronic migraine were included in the study.

The treatment schemes for MOH are based on expert consensus and withdrawal strategies are the most challenging part of treatment. In our study, numerical rating scale for headache intensity, overused medication consumption per month, headache frequency (day/month) and the duration of each attack (hour/day) decreased significantly in the first month compared to pre-treatment (p < 0.01). 

Conclusion – Our study suggests that GON blockade can be used as a good alternative therapy in the treatment of MOH.

Greater occipital nerve blockade for the preventive treatment of chronic migraine: A randomized double-blind placebo-controlled study.

BACKGROUND: Greater occipital nerve blockade for the prevention of chronic migraine has a limited evidence base. A robust randomized double-blind, placebo-controlled trial is needed. METHODS: This double-blind, placebo-controlled, parallel-group trial, following a baseline period of four weeks, randomly assigned patients of chronic migraine 1:1 to receive four-weekly bilateral greater occipital nerve blockade with either 2 ml of 2% (40 mg) lidocaine (active group) or 2 ml of 0.9% saline (placebo) injections for 12 weeks. The primary and key secondary efficacy endpoints were a change from the baseline in the mean number of headache and migraine days and the achievement of ≥50% reduction in headache days from baseline across the weeks 9-12 respectively. Safety evaluations included the documentation and reporting of serious and other adverse events. RESULTS: Twenty-two patients each were randomly allocated to the active and placebo group. Baseline demography and clinical characteristics were similar between the two groups. Mean headache and migraine days at baseline (±SD) were 23.4 ± 4.4 and 15.6 ± 5.7 days in the active group and 22.6 ± 5.0 and 14.6 ± 4.6 days in the placebo group respectively. The active group compared to the placebo had a significantly greater least-squares mean reduction in the number of headache and migraine days (-4.2 days [95% CI: -7.5 to -0.8; p = 0.018] and -4.7 days [95%CI: -7.7 to -1.7; p = 0.003] respectively). 40.9% of patients in the active group achieved ≥50% reduction in headache days as compared with 9.1% of patients receiving a placebo (p = 0.024). Overall, 64 mild and transient adverse events were reported by 16 patients in the active group and 15 in the placebo. No death or serious adverse events were reported. CONCLUSION: Four-weekly greater occipital nerve blockade with 2% lidocaine for 12 weeks was superior to placebo in decreasing the average number of headache and migraine days in patients with chronic migraine with a good tolerability profile.Clinical trial.gov no. CTRI 2020/07/026709.

Functional brainstem representations of the human trigeminal cervical complex.

BACKGROUND: The human in-vivo functional somatotopy of the three branches of the trigeminal (V1, V2, V3) and greater occipital nerve in brainstem and also in thalamus and insula is still not well understood. METHODS: After preregistration (clinicaltrials.gov: NCT03999060), we mapped the functional representations of this trigemino-cervical complex non-invasively in 87 humans using high-resolution protocols for functional magnetic resonance imaging during painful electrical stimulation in two separate experiments. The imaging protocol and analysis was optimized for the lower brainstem and upper spinal cord, to identify activation of the spinal trigeminal nuclei. The stimulation protocol involved four electrodes which were positioned on the left side according to the three branches of the trigeminal nerve and the greater occipital nerve. The stimulation site was randomized and each site was repeated 10 times per session. The participants partook in three sessions resulting in 30 trials per stimulation site. RESULTS: We show a large overlap of peripheral dermatomes on brainstem representations and a somatotopic arrangement of the three branches of the trigeminal nerve along the perioral-periauricular axis and for the greater occipital nerve in brainstem below pons, as well as in thalamus, insula and cerebellum. The co-localization of greater occipital nerve with V1 along the lower part of brainstem is of particular interest since some headache patients profit from an anesthetic block of the greater occipital nerve. CONCLUSION: Our data provide anatomical evidence for a functional inter-inhibitory network between the trigeminal branches and greater occipital nerve in healthy humans as postulated in animal work. We further show that functional trigeminal representations intermingle perioral and periauricular facial dermatomes with individual branches of the trigeminal nerve in an onion shaped manner and overlap in a typical within-body-part somatotopic arrangement.Trial registration: clinicaltrials.gov: NCT03999060.

Transient side shift of cluster headache attacks after unilateral greater occipital nerve injection.

Attacks of cluster headache (CH) are usually side-locked in most, but not all, patients. In a few patients, the side may alternate between or, rarely, within cluster episodes. We observed seven cases in whom the side of CH attacks temporarily shifted immediately or shortly after unilateral injection of the greater occipital nerve (GON) with corticosteroids. In five patients with previously side-locked CH attacks and in two patients with previously side-alternating CH attacks, a side shift for several weeks occurred immediately (N = 6) or shortly (N = 1) after GON injection. We concluded that unilateral GON injections might cause a transient side shift of CH attacks through inhibition of the ipsilateral hypothalamic attack generator causing relative overactivity of the contralateral side. The potential benefit of bilateral GON injection in patients who experienced a side shift after unilateral injection should be formally investigated.

Management and outcomes of persistent headache after accidental dural puncture in the obstetric population: A 9-year prospective audit.

OBJECTIVE: To assess the effectiveness and safety of a novel management pathway in the obstetric population presenting to a pain medicine clinic with persistent headache after accidental dural puncture (PHADP). BACKGROUND: Accidental dural puncture (ADP) can result in headaches that persist for months to years. These headaches can be a therapeutic challenge, often cause severe disability, and management pathway remains obscure. METHODS: Obstetric patients with PHADP referred to a pain medicine physician were prospectively followed up in a longitudinal audit of a novel management pathway. ADP reports dated from 2008 until 2019. Initial management included brain imaging and pharmacological agents. Patients who failed to respond were offered greater occipital nerve (GON) block with depot methylprednisolone followed by pulsed radiofrequency (PRF) treatment. A headache diary was completed for 4 weeks prior to commencing treatment and maintained for 24 weeks following an intervention. Data collected included use of epidural blood patch to manage postdural puncture headache, past history of headache, severity of headache, duration of persistent headache, low back pain, and employment status. RESULTS: Over the 9-year period, a cohort of 54 obstetric patients with PHADP with a 16-gauge Tuohy needle were reviewed in the pain clinic. Forty patients presented with chronic daily headache (40/54, 74%). Brain imaging did not reveal any sign of intracranial hypotension in 50 patients (50/54, 93%). Mean follow-up period was 5.7 years. Two patients were lost to follow-up (2/54, 4%). Pharmacological management was effective in 17 patients (17/52, 33%). Medical management failed to improve symptoms in 35 patients (35/52, 67%), and they were offered GON block. Fourteen (14/35, 40%) patients refused the intervention. Nerve block was performed in 21 patients and produced durable benefit lasting 24 weeks in 18 patients (18/21, 86%). Three patients underwent PRF treatment to GONs and all three (100%) reported durable benefit. At final follow-up, mean monthly headache frequency was 5.9 for the medical management group, 8.6 for the refused nerve block group, and 4.1 in patients who received GON treatment (p < 0.001). CONCLUSION: ADP can cause chronic headaches that persist beyond 3 years. Interventions targeting the GONs appear to have a role in the management of PHADP.

Preventive effect of greater occipital nerve block on patients with episodic migraine: A randomized double-blind placebo-controlled clinical trial.

OBJECTIVE: Since the data regarding the efficacy of greater occipital in episodic migraines are rare, we aimed to examine the efficacy of greater occipital block in the prophylaxis of episodic migraines without aura and compare different injectable drug regimens. METHODS: In a randomized, double-blind placebo-controlled trial, adult patients suffering from episodic migraines without aura were randomized to one of the following: triamcinolone, lidocaine, triamcinolone plus lidocaine, and saline. Patients were assessed at baseline, one week, two weeks, and four weeks after the injection for severity and duration of headaches and side effects. RESULTS: Fifty-five patients completed the study. Repeated measures ANOVA indicated that the severity and duration decreased significantly after the greater occipital block (P < 0.001, P = 0.001 respectively) in all four groups. However, there was no difference between groups at any study time points (P > 0.05). In paired sample T-test, only groups 2 and 3 with lidocaine as a part of the injection showed a significant decrease in frequency compared to the baseline (P = 0.002, P = 0.019). Three patients reported side effects with a possible association with triamcinolone. CONCLUSION: Greater occipital block with a local anesthetic significantly decreases the number of attacks in episodic migraine, whereas no injection was superior to the placebo in regards to the duration and severity of the headaches.Trial Registration Information: Iranian Registry of Clinical Trials (IRCT). Registration number: IRCT2017070334879N1. https://www.irct.ir/trial/26537.

Efficacy and tolerability of combination treatment of topiramate and greater occipital nerve block versus topiramate monotherapy for the preventive treatment of chronic migraine: A randomized controlled trial.

OBJECTIVE: To compare the efficacy and tolerability of combination treatment of topiramate and greater occipital nerve block to topiramate monotherapy in adult chronic migraine patients. BACKGROUND: Options for the preventive treatment of chronic migraine are limited and costly. Combination treatments do not have an evidence base yet. METHODS: This was a parallel group, 3 arms with 1:1:1 allocation ratio randomized controlled study in consecutive adult chronic migraine patients attending Headache Clinic in a tertiary care hospital. Patients received either topiramate monotherapy 100 mg/day (group A), or topiramate plus greater occipital nerve block with 40 mg lidocaine (2%) and 80mg (2 ml) methylprednisolone as the first injection followed by monthly injections of lidocaine for the next 2 months (group B) or topiramate plus greater occipital nerve block with 40 mg lidocaine (2%) injections monthly for 3 months (group C). The primary endpoint was the mean change in monthly migraine days at Month 3. Multiple secondary endpoints were assessed that included among others, achievement of ≥50% reduction in mean monthly headache days compared to baseline at Month 3 and assessment for any adverse events. RESULTS: One hundred and twenty-five patients were randomized; 41 to group A, 44 to group B, and 40 to group C. Efficacy assessments were done for 121 patients. Patients receiving combination treatment of topiramate and greater occipital nerve block with steroids and lidocaine and greater occipital nerve block with only lidocaine compared to topiramate monotherapy showed greater reductions in monthly migraine days at Month 3 (-9.6 vs -7.3 days; p = 0.003) and (-10.1 vs -7.3 days; p < 0.001) respectively. Greater proportion of patients in both the combination treatment groups (added greater occipital nerve block with and without steroid) achieved ≥50% reduction in mean monthly headache days [71.4% vs 39%; OR (95% CI) 3.9(1.6-9.8); p = 0.004] and [62.4% vs 39%; OR (95% CI) 2.7(1.1-6.7); p = 0.034] respectively, compared to those receiving topiramate monotherapy. Adverse effects between the groups were comparable although patients receiving combination treatment with added greater occipital nerve block reported transient adverse effects like post-injection dizziness, local site swelling, and pain. No serious adverse event was reported. CONCLUSION: Combination treatments of topiramate with monthly injections of greater occipital nerve block were more effective in reducing monthly migraine days in chronic migraine than topiramate monotherapy at Month 3. Combination treatments were well tolerated.

Treatment of occipital neuralgia using onabotulinum toxin A.

OBJECTIVES: To determine the effectiveness of botulinum toxin in a sample of patients diagnosed with greater occipital nerve neuralgia. MATERIAL AND METHODS: Twenty-nine patients (28 females, 1 male) were treated for greater occipital nerve neuralgia with onabotulinum toxin type A; the Visual Analog Pain Scale was used to determine pain severity at treatment and again 12 weeks after application. RESULTS: Average doses of onabotulinum toxin type A of 18.66±6.44 U per nerve and 35.96±12.89 U per patient were utilized. Average pain severity among the sample was 9.81±0.89 prior to botulinum toxin application and 3.68±2.31 points (p<0.0001) twelve weeks after application. Pain frequency decreased from 29.93±0.37 to 12.17±11.05 days with pain per month (p<0.0001). Six patients reported absence of pain after application (p=0.023). Dose did not correlate with the degree of clinical response observed, and no side effects were reported. CONCLUSION: Our findings suggest onabotulinum toxin type A is a safe and effective treatment alternative for patients suffering from refractory greater occipital nerve neuralgia.

Effects of greater occipital nerve block with local anesthetic and triamcinolone for treatment of medication overuse headache: an open-label, parallel, randomized, controlled clinical trial.

AIM: There is a paucity of evidence and consensus on exactly how to carry out the detoxification process. To examine the effect of a greater occipital nerve block (GONB) in the detoxification process, we conducted an open-label, parallel, randomized, controlled clinical trial. MATERIALS AND METHODS: In order to conduct this study, 54 medication-overuse headache (MOH) patients were recruited and allocated randomly to group A (n = 27) or B (n = 27). In both groups, patients underwent detoxification processes without any acute migraine medication or analgesics. During the run-in period, all patients in both groups received the same education, managed by a neurologist and nutritionist. All patients were offered maximally 300 mL of promethazine syrup (5 mg/5 mL) to be taken 10 mg every 8 h during the first 10 days of the study. A 2-mL syringe containing 1 mL of lidocaine 2% and 1 mL of triamcinolone 40 mg/mL was prepared for each patient of group A for conducting GONB. Characteristics of headache attacks, including headache severity, frequency, and duration, were assessed at baseline and after 3 months of intervention. RESULTS: Twenty-six patients in group A (96.3%) and twenty-three in group B (85.2%) completed detoxification, and were thus cured of MOH (P = 0.351). The present study revealed that GONB with local anesthetic and triamcinolone significantly improved the characteristics of headache, including frequency (- 13.66 in group A and - 7.55 in group B), duration (- 7.92 in group A and - 5.88 in group B), and severity (- 3.44 in group A vs. - 1.33 in group B) in group A compared to control (all P value < 0.05). CONCLUSIONS: Although both detoxification programs were effective, detoxification with GONB resulted in better outcomes. TRIAL REGISTRATION: Iranian Registry of Clinical Trials (registration number; IRCT20150906023922N2).

Comparison of the clinical efficacy of bilateral and unilateral GON blockade at the C2 level in chronic migraine.

The main purpose of this study was to retrospectively compare the unilateral and bilateral application of proximal greater occipital nerve (GON) block at the C2 level in the treatment of chronic migraine disease. In chronic migraine patients who underwent GON blockade, the average number of migrainous painful days per month, the average duration of pain in attacks, the highest visual analogue scale (VAS) score in pain intensity for one month, and total analgesic use were recorded before and after the block. According to the GON block protocol applied by our clinic, the patients were treated for GON block 4 times a month, once a week. The data obtained were recorded before the treatment, in the 1st and 3rd months after the last injection, and the results were compared using the chi-square, Fisher, Mann-Whitney U, and Wilcoxon-signed rank tests. During the 3-month follow-up, the groups did not differ significantly in terms of the number of days with headache in 30 days, the average duration of headache, the highest VAS score in 30 days, and total analgesic use in 30 days. In both groups, the findings decreased in the 1st month and increased in the 3rd month compared to pre-treatment. However, results of both the 1st and 3rd months were significantly lower than pre-treatment (p<0.05), and there was a clinical benefit compared to pretreatment. While the GON block at the C2 level was effective in the treatment of chronic migraine, the superiority of bilateral application to unilateral application was not detected.

Single midline incision approach for decompression of greater, lesser and third occipital nerves in migraine surgery.

BACKGROUND: The traditional approach for occipital migraine surgery encompasses three separate surgical incisions in the posterior neck to decompress the greater occipital nerves (GON), lesser occipital nerves (LON), and third occipital nerves (TON). Other incisions have been investigated, including singular transverse incisions. We sought to evaluate a single, vertical midline incision approach for decompression of all six occipital nerves. METHODS: Using 10 cadaveric hemi-sides (5 fresh cadaver head and necks). Anatomic landmarks and the location of the bilateral GON, LON, and TON were marked according to previous anatomic studies. A single, midline 9-cm incision was made, and lateral skin flaps were raised to decompress or avulse all six nerves. RESULTS: Through the midline incision, the GON and TON were identified at 3.5 and 6.2 cm, respectively, inferior to a line bisecting the external auditory canal (EAC) and 1.5 cm lateral to the midline. The LON was identified as 6-cm inferior and 6.5-cm medial to a line bisecting the EAC in the plane just above the investing layer of the deep cervical fascia until the posterior border of the sternocleidomastoid was encountered. The LON had the greatest amount of variation but was identified lateral to the posterior border of the SCM. CONCLUSIONS: A single midline incision approach allows for successful identification and decompression of all six occipital nerves in migraine surgery.

Anatomy of the greater occipital nerve: implications in posterior fossa approaches.

PURPOSE: Because of its superficial location in the dorsal regions of the scalp, the greater occipital nerve (GON) can be injured during neurosurgical procedures, resulting in post-operative pain and postural disturbances. The aim of this work is to specify the course of the GON and how its injuries can be avoided while performing posterior fossa approaches. METHODS: This study was carried out at the department of anatomy at Bordeaux University. 4 specimens were dissected to study the GON course. Posterior fossa approaches (midline suboccipital, paramedian suboccipital, retrosigmoid and petrosal) were performed on 4 other specimens to assess potential risks of GON injuries. RESULTS: The GON runs around the obliquus capitis inferior (100%), crosses the semispinalis capitis (100%) and the trapezius (75%) or its aponeurosis (25%). Direct GON injuries can be seen in paramedian suboccipital approaches. Stretching of the GON can occur in midline suboccipital and paramedian suboccipital approaches. We found no evidence of direct or indirect GON injury in retrosigmoid or petrosal approaches. CONCLUSION: Our study provides interesting data regarding the risk GON injury in posterior fossa approaches. Direct GON injuries in paramedian suboccipital approaches can be avoided with careful dissection. Placing retractors in contact with the periosteum and performing a minimal retraction may help to avoid excessive GON stretching in midline suboccipital and paramedian suboccipital approaches. Furthermore, the incision for retrosigmoid approaches should be as lateral as possible and not too caudal. Finally, avoiding extreme patient positioning reduces the risk of GON stretching in all approaches.