The Effect of Ganglion Sphenopalatine Block Versus Placebo on Persistent Headache Following COVID-19 Infection

The Effect of Ganglion Sphenopalatine Block (SPG-block) Versus Placebo on Persistent Headache Following COVID-19 Infection: a Randomised, Blinded, Clinical Trial

The purpose of this study is to evaluate the effect of the ganglion sphenopalatine block (SPG block) on persistent headache following acute COVID-19 infection.

Adult patients with persistent headache following COVID-19 infection will be enrolled in the study. The patients will be randomised into three groups; bilateral SPG-block withto receive local anesthetic (lidocaine + ropivacaine), bilateral SPG-block with placebo (isotone NaCl) or bilateral "sham"-block with placebo (isotone NaCl).

Primary outcome is hyperactivity in the sphenopalatine ganglion assessed by pain intensity (0-100mm on a visual analogue scale, VAS) of the headache in standing position 30 minutes after block in the group Ropicavain-Lidocain and "sham".

Inclusion Criteria:

• Age > 18 years
• Moderate to severe headache (NRS >= 3) with self reported duration of minimum 6 hours during the past week as well as moderate to severe headache (NRS >= 3) on the day of intervention.
• Onset of headache during or maximum 4 weeks after PCR-verified COVID-19 infection.
• Headache must have persisted for at least 4 weeks following COVID-19 diagnosis.

Exclusion Criteria:

• Patients who cannot cooperate to the study
• Patients who does not understand or speak Danish
• Allergy to the drugs used in the study
• Has taken opioids within 12 hours prior to intervention
• History of migraine or persistent headache before COVID-19 infection.
• Active COVID-19 infection (defined by the Danish Goverment regulations, i.e. 48 hours after last symptoms (omitting long term effects) or 7 days after positive COVID-19 test if no symptoms.