Chronic migraine is a debilitating neurological disorder that significantly affects patients' daily functioning, mental health, and quality of life. Management typically includes acute and preventive treatments, but effectiveness can be limited due to medication overuse or delayed onset of action. OnabotulinumtoxinA injections provide proven long-term preventive benefits, while Greater Occipital Nerve (GON) block offers rapid but short-term relief. Although both treatments are used individually, evidence on the combined effect is limited. This randomized controlled trial aims to evaluate the efficacy and safety of combining OnabotulinumtoxinA injections with GON block, assessing improvements in headache frequency, severity, and patient quality of life compared to single therapy.

Chronic migraine is a disabling neurological disorder that affects a significant proportion of the population, leading to substantial functional, psychological, and economic burdens. Despite the availability of acute and preventive treatments, many patients continue to experience frequent headaches due to limited efficacy, delayed onset of action, or medication overuse.

OnabotulinumtoxinA injections have been shown to provide sustained preventive benefits in chronic migraine, reducing headache frequency and improving patient quality of life. Greater Occipital Nerve (GON) block offers rapid relief of headache symptoms, though the effect is typically short-term. While both interventions are used individually, there is limited evidence on the benefits of combining them to achieve both immediate and sustained symptom control.

This randomized controlled trial aims to evaluate the safety and efficacy of combining OnabotulinumtoxinA injections with GON block in adult patients with chronic migraine. Participants will be randomly assigned to one of the following groups: OnabotulinumtoxinA alone, GON block alone, combined therapy, or standard care. Headache frequency, severity, duration, and patient-reported quality of life will be assessed over a 12-week follow-up period. Adverse events and tolerability will also be recorded systematically.

The study is conducted under the supervision of an independent ethics committee to ensure participant safety and adherence to Good Clinical Practice standards. Findings from this study aim to provide evidence on whether an integrated therapeutic approach can offer superior relief and improve long-term outcomes for patients with chronic migraine.

Inclusion Criteria:

• Diagnosis of chronic migraine according to the International Classification of Headache Disorders, 3rd edition (ICHD-3): headache occurring on ≥15 days per month for more than three months, with at least 8 days per month exhibiting migraine features. (International Headache Society, 2013)
• Age > 18 years
• Stable preventive migraine regimen for at least two months prior to recruitment

Exclusion Criteria:

• Co-morbid other
• Prior treatment with BoNT-A or GONB for headache within the previous 3 months.
• Known hypersensitivity to BoNT-A or local anesthetics.
• Cervical anatomical abnormalities that hinder proper localization of injection sites or compromise the safety of the procedure
• Neuromuscular junction disorders (e.g., myasthenia gravis).
• Coagulation disorders or anticoagulant therapy that contraindicates nerve block.
• Significant psychiatric comorbidity that would impair proper pre and post treatment assessment.
• Pregnancy.

randomized, assessor-blinded, controlled trial will include 90 patients diagnosed with chronic migraine. Participants will be randomly assigned to one of three treatment groups: Group 1 (n = 30) will receive BoNT A combined with GONB; Group 2 (n=30) will receive BoNT-A alone; and Group 3 (n = 30) will receive a GONB alone. Randomization will be performed using a computer-generated allocation sequence. Block randomization will be employed to ensure balanced allocation across the groups throughout the enrollment period. Randomization sequence will be generated by an independent investigator who is not involved in participant recruitment, clinical evaluation, intervention administration, or data analysis. Allocation concealment will be maintained using sequentially numbered, opaque, sealed envelopes (SNOSE), This procedure minimizes selection bias and preserves the integrity of the randomization process.