Greater Occipital Nerve Injection

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Greater Occipital Nerve Injection
Indication	Occipital Neuralgia
Syringe	3mL
Needle	27-30G
Steroid	optional 4mg dexamethasone'"`UNIQ--ref-00000001-QINU`"'
Local	1-3mL of anaesthetic
Volume	1-3mL

Background

• Therapeutic and diagnostic for occipital neuralgia
• Usually performed by targeting the tender points that approximate the affected branches of the C2 nerve, either the greater or lesser occipital nerve.
• The greater occipital nerve is 2cm inferior and lateral to the external occipital protuberance, and is between ~8-18 mm deep. It can also be identified at one third of the distance from the external occipital protuberance to the mastoid process.
• The lesser occipital nerve is 5cm lateral to the external occipital protuberance.

Indications

• Suspected or confirmed occipital neuralgia
• Migraine refractory to conservative treatment
• Post-lumbar puncture headache refractory to conservative treatment
• Cluster headache, occipital neuralgia, cervicogenic headache, or migraine with occipital nerve irritation or tenderness

Contraindications

• Infection overlying injection site

Procedure

Ultrasound Guided

• In-plane technique
• Prone, side-lying, or seated position with the head slightly flexed.
• Stand contralateral to the injection site, in line with the transducer and with the ultrasound screen on the opposite side
• Using a high-frequency linear array transducer, localize the C2 spinous process which is bifid. The C1 spinous process is not bifid.
• Slide the probe laterally (away from yourself) towards the ipsilateral lamina of C2.
• Rotate the lateral part of the transducer cephalad until the transverse process of C1 is visualized (around 20–30 degrees).
• Identify the muscular tissue planes and the greater occipital nerve
• Colour doppler can be used to identify the occipital artery which lies just medial to the greater occipital nerve
• Insert the needle in-plane from medial to lateral and advance until the needle tip is close to the nerve.

See Palamar et al for a review on technique.

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Non-ultrasound Guided

• Patient in position of comfort allowing access to posterior head and neck. (laying prone or sitting with head down in arms)
• Identify Greater Occipital Nerve (GON), which may be palpated 1.5-2.5 cm inferior to occipital protuberance and ~1.5-2 cm lateral to midline
• Cleanse skin with betadine or chlorhexidine and allow to dry
• Insert needle over nerve at 90 degrees to skin until hit bone, then withdraw slightly
• Aspirate to ensure not in vessel.
• Inject ~1-3 mL of local anesthetic. (may inject small amount medial and lateral to nerve to ensure adequate block)
• Repeat on contralateral side, if indicated.

Maximum Doses of Anesthetic Agents

Agent	Without Adrenaline	With Adrenaline	Duration	Notes
Lidocaine	5 mg/kg (max 300mg)	7 mg/kg (max 500mg)	30-90 min	1% soln contains 10 mg/ml 2% soln contains 20 mg/ml
Mepivicaine	7 mg/kg	8 mg/kg
Bupivicaine	2.5 mg/kg (max 175mg)	3 mg/kg (max 225mg)	6-8 hr	0.5% soln contains 5 mg/ml May cause cardiac arrest if injected intravascularly Do not buffer with bicarbonate
Ropivacaine	3 mg/kg
Prilocaine	6 mg/kg
Tetracaine	1 mg/kg	1.5 mg/kg	3hrs (10hrs with epi)
Procaine	7 mg/kg	10 mg/kg	30min (90min with epi)

Complications

Complications are rare due to superficial location and lack of major surrounding structures.

• Damage to surrounding structures
• Bleeding
• Infection
• Repeated blocks with steroid may result in transient dizziness or elevated blood pressure, and the patient may rarely become cushingoid.

Aftercare

• The procedure may be repeated if pain recurs