Why Anesthetic Injections Failed to Relieve Temple Migraine Pain: A 'Hidden Nerve' Was to Blame [Health Check]

[Financial News] Domestic researchers have presented anatomical evidence that a 'hidden nerve branch' may be responsible for persistent pain in roughly one in five patients even after they undergo a temple nerve block.
The study was conducted by a team of professors comprising Hyunjin Shin of the Department of Ophthalmology at Konkuk University Hospital, Yoo-jin Choi of the Department of Anatomy at Konkuk University, Shin, Kang-Jae of the Department of Anatomy at Dong-A University, Heejin Kim of the Department of Anatomy at Yonsei University, and Shin-hyo Lee of the Department of Anatomy at Wonkwang University. The findings were published in Scientific Reports, an international journal in the Nature portfolio.
A sensory nerve called the zygomaticotemporal nerve runs through the temple area. It provides sensation to the side of the forehead and the front of the temple. When it becomes hypersensitive or compressed, it can cause chronic temple migraines and neuralgia. A nerve block, which involves injecting a local anesthetic around the nerve to block pain signals, is commonly used to treat this pain and is also used to manage pain after craniofacial surgery.
The problem is that this nerve branches in anatomically variable ways from person to person. Previous studies have found that many patients have a separate accessory branch in addition to the main nerve branch. However, nerve blocks have generally been performed based only on the location of the main branch. As a result, the accessory branch may fall outside the anesthetized area, leaving pain insufficiently relieved or allowing it to recur. Treatment outcomes have therefore varied from patient to patient.
The research team examined the presence and location of accessory branches through a cadaveric dissection study. Accessory branches were identified in 7 of 36 sides (19.4%); five were found on one side only, while two were observed on both sides. The points where the accessory branches emerged were clustered within an average of 3.4 millimeters of the marginal tubercle, a small projection on the edge of the cheekbone that can be felt by hand.
Shin explained, "One possible reason that pain or altered sensation remains even after a conventional nerve block is the presence of an accessory nerve branch. This study is significant because it shows that the location of an accessory nerve branch can be identified using a bony structure that can be palpated from the outside."
The research team expects these findings to help improve the accuracy of temple nerve blocks and reduce unnecessary damage to surrounding nerves. However, the team noted that additional clinical research is needed before a new injection technique can be applied in actual medical practice.
Shin has focused on identifying physical anthropological characteristics of Koreans that distinguish them from Westerners. By identifying problems arising in clinical practice and incorporating them into research, Shin has presented various clinically relevant anatomical resources that can be readily applied and widely used not only in the laboratory but also in actual surgery and patient care. Since 2016, Shin has been building a database of anatomical data for clinical applications in Koreans with support from the National Research Foundation of Korea (NRF) and was selected as an outstanding early-career researcher by the NRF. This study is also significant because it provides an anatomical standard that can improve the accuracy of temple nerve blocks in Koreans.


[email protected] Jung Myung-jin, Medical Correspondent Reporter