The Effect of Interventional Procedures on Serum CGRP and PACAP-38 Levels in Chronic Migraine

The study included 100 patients diagnosed with chronic migraine (CM) who received a diagnosis from the headache clinics of the Neurology Department of Adnan Menderes University Hospitals between May 2025 and May 2026. Inclusion criteria were patients over 18 years of age with chronic migraine. Written informed consent was obtained from all participants; patients with severe systemic diseases, occiput infections or injuries, and allergies to any of the substances used in the injection were excluded. All patients were clinically evaluated (detailed history including personal data, medical history, and migraine treatments used). All patients underwent ultrasound-guided bilateral GON blockade using a portable ultrasound system with a 7-13 MHz multifrequency transducer (ACUSON Juniper Ultrasound System, Siemens, Germany). Blood samples were collected before and one month after the procedure. Samples were collected between 9 and 11 am to avoid the effect of circadian rhythms on CGRP levels. Patients will need to discontinue any anti-inflammatory or analgesic medication within the last 48 hours. A blood sample will be taken from the non-dominant forearm to measure interictal serum CGRP-PACAP38 levels using commercial ELISA kits (Novus Biologicals Inc., USA) according to the manufacturer's instructions. Absorption levels will be measured with a spectrophotometer at a wavelength of 450 nm ± 2 nm. The detection limit for CGRP is 9.3 pg/mL.