Great Occipital Nerve Block Using Different Approach

Study Overview
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Brief Summary
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Great occipital nerve (GON) block is commonly applied for the pain management of occipital neuralgia, migraine, and cervicogenic headache. The GON orginates from the medial branch of the dorsal ramus of the C2 spinal nerve with variable contribution from the C3 dorsal ramus. After emerging from the suboccipital triangle, the nerve courses cephalad in an oblique trajectory between the semispinalis capitis (SC) and obliqus capitis inferior (OCI) muscles. This area was recognized as a potential location for GON injury. The nerve then passes through the trapezius muscle and courses medial to the occipital artery as it ascends to innervate the posterior scalp. Many practitioners perform GON injections using a conventional approach, relying solely on superficial bone-based anatomic landmarks to infiltrate local anesthetic and corticosteroid around the nerve at the level of the superior nuchal line. Some clinicians also use fluoroscopy to confirm the location of bony landmarks. The ambiguity of these injections poses a risk of anesthetizing adjacent structures or injecting into vessels, such as the occipital artery. Very limited research has been done to quantify the risk of these injections, but a complication rate of 5% to 10% has been reported, including headache, dizziness, blurred vision, and syncope. Ultrasound guidance is increasingly used to mitigate these risks and improve the efficacy of GON injections. Multiple studies have demonstrated successful ultrasound-guided GON blockade at the superior nuchal line and improvement in pain scores compared with nonguided injections. C2 level GON block using ultrasound targets interfascial plane between OCI and SC muscles. However, a pain physician who begins ultrasound guided injections migth feel very difficult targeting interfascial plane exactly. Since GON orginiates from deep space of suboccipital triangle, it is expected that injection within OCI muscle might have similar effect with the effect of injection into interfascial plane. We assume that if the local anesthetics is injected within OCI muscle, the effect of GON block will be generated by the diffusion of injected local anesthetics.

Official Title
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Comparison of Pain Relief and Block Success of Great Occipital Nerve Block Using Different Approach Method at C2 Level

Conditions
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Pain, Chronic

Intervention / Treatment
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* Procedure: Greater occipital nerve block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Cervicogenic headache Migraine Occipital neuralgia Exclusion Criteria: bilateral headache cervical spine surgery within 1 year before loss of sensory sensation at the dermatome of GON innervation anatomical defect at the region of procedure coagulopathy pregnancy or breast feeding allergy to local anesthetics

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: interfascial plane group<br>injection into inferfascial plane | Procedure: Greater occipital nerve block<br>* Greater occipital nerve block using ultrasound guidance<br>|
| Experimental: intramuscular group<br>injection into obliqus capitis inferior muscle | Procedure: Greater occipital nerve block<br>* Greater occipital nerve block using ultrasound guidance<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Numerical rating scale | Numerical rating scale after GON block | Baseline, 30 minutes, 2 weeks, 4 weeks after the completion of GON block | 
| block success | block success after GON block | Baseline, 30 minutes after the completion of GON block | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Side effect after GON block | Side effect after GON block | Baseline, 30 minutes after the completion of GON block |