A Study Investigating the Efficacy of GON Blocks.
Condition: Migraine; Chronic Migraine, Headache
MeSH terms: Migraine Disorders; Headache
Study type: Interventional
Phase: Phase 4

Summary: 
      Greater occipital nerve block ("GON block") is carried out extensively in the treatment of
      chronic migraine, but more research is required to understand the effectiveness of the
      procedure. It consists of a superficial injection of local anaesthetic and steroid around a
      nerve at the back of the head that supplies sensation to part of the scalp. This study
      intends to provide more detailed information on the effectiveness, safety and tolerability of
      GON block with local anaesthetic and steroid in patients with chronic migraine. It does this
      by comparing it to a dummy (placebo) procedure (a needle is inserted near the nerve, but no
      therapeutic substance is injected). It is a "cross-over study": all patients will receive
      both the GON block and the dummy procedure (not necessarily in that order), with a period in
      between to assess the response to the first injection. The GON block will entail an injection
      of 2 mls of 2% lidocaine (a local anaesthetic) and 80 mg of DepoMedrone (a steroid) through a
      fine needle (a total of 4 mls). The dummy procedure will consist of an injection of 4 mls of
      normal saline (a solution of common salt and water) through a fine needle. Patients will be
      followed up at various time points throughout 6 months whilst being enrolled on the study.
    

Detailed description: 
      Chronic migraine is characterised by frequency of headache ≥ 15 days per month for more than
      3 months. The location can be unilateral or bilateral. Usually described as pulsating in
      nature, it may be aggravated by, or cause avoidance of, routine activities of daily living.
      There can be associated light and noise sensitivity. Greater occipital nerve (GON) blockade
      with local anaesthetics and steroids has been used as a preventative strategy for a range of
      headaches including, migraine, cluster headache and hemicrania continua.

      The occipital nerves have a sensory distribution in the occipital area. The greater occipital
      nerve derives most of its fibres from the C2 dorsal root [6]. It passes over the superior
      nuchal line, mid-way between the mastoid process and the occipital protuberance, just lateral
      to the insertion of the nuchal ligaments. The lesser occipital nerve passes lateral to the
      greater occipital nerve, over the nuchal ridge. Although the exact mechanism of action
      remains unclear, injection of steroid in the vicinity of GON nerve can have both a local
      effect (decreasing nociception) and a delayed central nociceptive response, possibly through
      an action on trigeminocervical relay

      Although GON block is carried out extensively in the prophylaxis of chronic migraine, the
      evidence remains equivocal. In the UK, the National Institute for Clinical Excellence have
      yet to include GON blocks in their guidance and protocols on the treatment of both chronic
      headache and migraine. This randomised, single-blinded, placebo-controlled multicentre
      cross-over study intends to assess the efficacy, safety and tolerability of greater occipital
      nerve block with local anaesthetic and steroid in patients with chronic migraine with the
      primary objective to investigate any improvement in disability associated with chronic
      migraine disorder. We also intend to identify any economic outcomes associated with these
      injections in the management of chronic migraine.

      GON block with local anaesthetic and steroid for chronic migraine and the placebo procedure
      will be performed in the outpatient setting. They will be carried out only by appropriately
      qualified members of the research team adhering to strict aseptic conditions and following
      standard operating protocols with regards to admission and discharge criteria in the
      outpatient settings.

      GON block is routinely carried out in the UK and poses minimal risks to the patient. Although
      GON block is carried out extensively in prophylaxis of chronic migraine, the evidence remains
      equivocal. In the UK, the National Institute for Health and Care Excellence (NICE) have yet
      to include GON blocks in their guidance and protocols on the treatment of both chronic
      headache and migraine.

      The aim of this study is to assess the efficacy, safety and tolerability of greater occipital
      nerve block with local anaesthetic and steroid in patients with chronic migraine of more than
      three months' duration.
    

Intervention name(s): Combined Depo-Medrone and Lidocaine; Sodium Chloride 0.9% Inj
Intervention type(s): Drug; Drug
Intervention description(s): Patients will be randomised 1:1 to receive the active or placebo arm. The nerve is located along the superior nuchal line, where it bilaterally lies medial to the occipital artery. The scalp is prepped with alcohol and using 23G needle, the IMPs are injected at a 90 degrees angle till the bony endpoint is obtained. A combination of 2 mls of 2% lidocaine and 80mg methylprednisolone will be administered.
Patients who no longer receive any benefit will be crossed over to the placebo arm.; Patients will be randomised 1:1 to receive the active or placebo arm. The nerve is located along the superior nuchal line, where it bilaterally lies medial to the occipital artery. The scalp is prepped with alcohol and using 23G needle the 4mls of normal saline (0.9%) are injected at a 90 degrees angle till the bony endpoint is obtained. Patients who no longer receive any benefit will be crossed over to the active arm.
Other intervention name(s): Methylprednisolone Acetate BP 40mg/mL:; Lidocaine Hydrochloride 2%:; normal saline 0.9%
Intervention MeSH terms: Methylprednisolone; Methylprednisolone Acetate; Methylprednisolone Hemisuccinate; Prednisolone; Prednisolone acetate; Lidocaine; Prednisolone hemisuccinate; Prednisolone phosphate
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Consented participants will be individually randomised by the Principal Investigator (PI) in a 1:1 ratio to receive either the GON block (active group) or the placebo injection (control group).
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: Chronic migraine, GON blocks