At the end of our study, patients with CM reported a significant decrease in pain intensity, analgesic consumption, number of headache days, and number of migraine attacks following GONB + PRF treatment compared with those undergoing GONB treatment. To the best of our knowledge, this is the first prospective double-blind, randomized controlled study with a long follow-up period to evaluate the effectiveness of combining GONB and PRF in patients with CM.

The existing literature exploring the application of PRF to the GON in patients with migraines is limited [10]. In this prospective, double-blind study, we investigated the effectiveness of combining PRF and GONB and discovered that the combination was more efficacious than GONB alone in the treatment of CM.

Occipital and multiple cranial nerve blocks have been shown to effectively prevent CM [17, 18]. It has been reported that GONB with a local anesthetic may be beneficial in patients with migraine who are unresponsive to oral treatment or who do not prefer prophylactic medications. Additionally, the side effects of prophylactic migraine treatments limit the use of these drugs. Even a single GONB treatment session might be effective in some patients [19, 20]. In a previous review, Inan et al. reported that repetitive peripheral nerve blocks provide long-term migraine relief for most patients with CM [21]. Despite the extensive history of using peripheral nerve blocks in the management of headache disorder, standardized techniques, local anesthetic types, dosages, or intervention frequencies for patients with migraine are lacking. Furthermore, there is limited evidence regarding the long-term efficacy of a single GONB session for the treatment of migraine. In a randomized, double-blinded clinical trial, Palamar et al. compared the effectiveness of an USG GONB using bupivacaine versus placebo in facilitating clinical improvement in patients with refractory migraine without aura [19]. They observed a decrease in headache intensity in the first month following the injection, suggesting that USG should be used to increase the effectiveness of the injection. However, the short follow-up duration is a limitation of their study. In a study by Kashipazia et al., researchers compared GONB with triamcinolone versus lidocaine [20]. They reported reduced pain severity, migraine frequency, and analgesic consumption up to 2 months after the GONB. Alternatively, Güner et al. assessed the efficacy of PRF for patients with CM and found improvements that persisted for 3 months post-treatment [13]. Unlike in our study, Güner et al. did not use GONB.

Perdecioglu et al. conducted a clinical trial wherein one group underwent non-invasive PRF application (transcutaneously applied PRF with pad adhesion), while the other received GONB therapy. When the two groups were compared after 4 weeks, they found greater decreases in the 1-month VAS scores in the GONB group, although the difference was not significant [12]. This may be because the GON is impervious to blockage through transcutaneous applications, thereby precluding the opportunity for combined therapeutic approaches. Furthermore, the efficacy between needle-based and non-invasive techniques may vary.

A previous study reported a significant reduction in the frequency of attacks in the RF group in the initial month of the trial. This trial involved repeating the block four times for both groups, administering steroids to one group, and using pulsed radiofrequency in the other group during the final session. However, no significant differences between the groups were observed in other aspects [11]. Conversely, in our study, the procedure was not repeated, and the patient underwent invasive intervention only once. Additionally, we observed a sustained effect for 6 months in the GONB + PRF group.

In our study, when GONB and PRF were combined, there was a significant reduction in the mean VAS score from the first month onwards, as well as a decrease in the mean number of analgesics consumed and the frequency of migraine attacks, when compared to those in the GONB group.

Additionally, no complications were observed in our study. USG and PRF needles with neurostimulatory properties seem to be more reliable in confirming the location of the occipital nerve and nerve blocks, which reduces the risks associated with intra-arterial injection. Another advantage is that a single session of the application is convenient for patients and physicians.

Our results showed that the combination of USG PRF and GONB is an effective treatment for patients with CM and showed that the combined treatment prolongs the effect of GONB. The mean VAS score, analgesic consumption, and number of migraine attacks were significantly lower in the GONB + PRF group than in the GONB group at all follow-up assessments. In addition, this study showed that PRF treatment following the blockade resulted in at least a 60% reduction in the mean VAS score, analgesic consumption, and number of migraine attacks compared with those at baseline, which persisted for 6 months. Therefore, the benefits of combining GONB and PRF include satisfactory analgesia, reduced analgesic consumption, reduced migraine attacks, and reduced headache days, with effects lasting at least 6 months.

PRF was first applied to dorsal root ganglia for the treatment of chronic lumbosacral pain and found to be effective [22]. Afterwards, it was shown to be an effective method in chronic pain such as trigeminal neuralgia, occipital neuralgia, neuropathic pain, and shoulder and knee pain [23].

PRF has been shown to cause changes at the molecular level and changes in neural activity, as well as long-term depression of pain transmission in the mechanism of action [24]. Similar to our results, in a study conducted for chronic cervical radicular pain, combined treatment was found to be more effective than both selective nerve root block alone and PRF treatment alone in reducing pain [25]. The combined effect we have shown in our study may be due to the long-term depression of pain transmission in addition to the modulation of the excitability of second-order neurons receiving input from trigeminal and cervical afferents provided by GONB [26].

This GONB procedure, which can be relatively painful and uncomfortable for patients, can be combined with PRF to prevent unnecessary discomfort and inconvenience for both patients and clinicians.

Additionally, GONB may cause complications such as nerve and vascular injury, infection and inflammation, and block procedures may necessitate repeated administration during routine follow-up to sustain the desired therapeutic effect. However, in our study, we saw that when combined with PRF, the effects lasted for a long time without the need for repetition.

This study is not without limitations. Notably, it focused solely on the clinical effects of combining GONB with PRF in patients with CM. Factors such as quality of life, disability, and headache impact were not assessed. The inclusion of such assessments could have provided further insights into the experiences of patients suffering from CM.

In conclusion, our findings provide evidence that combining GONB with PRF leads to a reduction in VAS scores, number of migraine attacks, and analgesic use for up to 6 months. Moreover, GONB + PRF was more effective than GONB alone. Furthermore, PRF may be preferred in combination with GONB therapy as a safe and effective method for managing CM. Future studies should evaluate the role of this treatment in improving the quality of life and psychological state of patients with CM.