Although migraine is not the most frequent primary headache in the world, its incidence is quite high, affecting more than 10% of the world’s population. Migraine is usually unilateral and moderate to severe. It worsens with daily physical activities, such as walking and climbing stairs, seriously affecting patients’ work and quality of life .
In addition to prophylactic (e.g., flunarizine, topiramate and amitriptyline) and acute (e.g., diclofenac sodium and triptans) migraine therapies, treatment of migraine triggers and other lifestyle factors that may aggravate the migraine tendency in patients is critical. Specific behavioral therapies, including biofeedback, teaching relaxation techniques and cognitive behavioral therapy (CBT), are also beneficial . However, these treatment modalities require patient education and, in some cases, specific behavioral skills. This may cause great confusion for elderly patients or patients who do not receive proper education.
Furthermore, the effect of nerve block on migraine has been documented. The cranial nerve block was an effective adjuvant therapy, which could reduce the intensity, duration and frequency of pain, and improve the satisfaction of migraine and central sensitization patients . A large retrospective cohort study showed that greater occipital nerve block can effectively reduce migraine . Li et al. reported a case of long-term effective treatment with pulsed radiofrequency of C2 dorsal root ganglion under ultrasound guidance . The application of trigger point therapy in migraine has also been reported . Moreover, SGB block has been confirmed to effectively treat migraine . However, studies evaluating SGB in the treatment of migraine are limited, and even a case report shows that SGB causes migraine attacks . In the present study, we found that ultrasound-guided SGB, once a week for four weeks, can significantly relieve the pain of migraine patients.
Ultrasound is a valuable tool for imaging soft tissue structures and nerves, guiding needle advancement and confirming the spread of the injectate around the target without exposing physicians and patients to the risks of radiation. There is a rapidly growing interest in ultrasound-guided SGB, as evidenced by the surging number of publications in the last few years [8, 24, 25]. It has been reported that 2 ml of 2% mepivacaine can be effective when SGB is performed at the level of the 6th cervical transverse process under ultrasound . About 6 ml of 0.15% ropivacaine was found to be sufficient for a successful SGB with fewer complications, which coincides with the present study .
The stellate ganglion is extensively connected with the cerebral cortex, hypothalamus, amygdala and hippocampus . SGB can effectively treat postherpetic neuralgia, hot flushes and night awakenings in survivors of breast cancer, tension headache and PTSD, in part by improving blood supply and inhibiting the connection between the stellate ganglion and the brain through sympathetic action within its innervation; however, the exact mechanism remains unclear [5, 6, 29–32]. Low melatonin levels have been reported in migraine patients and SGB has been shown to restore melatonin rhythm. Melatonin can effectively prevent migraines by inhibiting the synthesis of nitric oxide and the release of calcitonin-related peptides and antagonizing excitotoxicity caused by glutamate [33–35]. In addition, stress is the most common migraine trigger. In response to stress, sympathetic activity increases, leading to the release of migraine-associated neurotransmitters, such as dopamine and prostaglandins [36–38]. High dopamine levels can lead to nausea and vomiting, while increased prostaglandins can increase pain sensitivity and inflammation in migraine patients. SGB can regulate sympathetic nerve activity, thereby alleviating most of the symptoms in migraine patients.
MIDAS was designed to quantify headache-related disability over 3 months. The reliability and internal consistency of the MIDAS score are comparable to those of a previous questionnaire (Headache Impact Questionnaire). However, the MIDAS score requires fewer questions, is easier to score and provides intuitively meaningful information on lost days of activity in three domains [39, 40]. The MIDAS questionnaire was considered highly reliable and effective and was relevant to clinical judgment on medical care needs. In our study, the MIDAS score of patients was significantly decreased at 3-months follow-up. Besides, NRS scores decreased significantly one day and 3 months after SGB. The frequency of analgesic use was also significantly decreased after 3 months. These results suggest that SGB once a week for 4 weeks can reduce the headache and disability among migraine patients and improve their work and quality of life.
Two patients who were recruited but not included in the analysis experienced migraine aggravation after a single SGB treatment, suggesting that migraine has more complex mechanisms. Wulf et al. detailed complications after SGB. Most of them were related to the central nervous system (such as convulsions). Other serious complications included high-level subarachnoid block, high-level epidural block, pneumothorax and allergic reaction. All SGBs were performed without fluoroscopy . In our study, serious complications such as subarachnoid block, epidural block and convulsion were not observed. It is suggested that ultrasound-guided SGB is safer than fluoroscopy because ultrasound can clearly distinguish nerves, blood vessels and muscles, and monitor the puncture needle in real-time, while fluoroscopy has no such functions.