Chronological Change and Importance of Acupuncture Points Used in Bell's Palsy in Classical Literature

This study represents a comprehensive historical analysis of the acupuncture points used in the treatment of peripheral facial palsy (Bell's palsy) through the examination of 11 classical Chinese acupuncture texts, covering a period of 1,592 years, from the Qin dynasty (282 CE) to the Qing dynasty (1874 CE). The main objective of the research was to identify which acupuncture points are most important in the current clinical treatment of Bell's palsy, based on the analysis of frequency of use, meridian affiliation, and anatomical location across the centuries. The methodology involved the systematic analysis of original texts, comparing them with the 'Dictionary of Acupuncture Prescriptions' as a reference, and categorizing the points into three groups: local points (on the face), adjacent points (head and neck), and distal points (limbs). The results revealed that the terminology for facial palsy evolved significantly over time.

Initially, during the Qin and Sui-Tang dynasties, the term 'Koubi' (口僻) was predominant, evolving into 'Kowai' (口喎) during the Song dynasty, and finally becoming established as 'Koyan Waisha' (口眼喎斜) from the Ming dynasty onward. This terminological evolution reflects a progressive refinement in understanding the condition, moving from a general description of deviation to a specific characterization of mouth and eye involvement. The quantitative analysis showed that the mean number of points used was 10.5 for local points, 2 for adjacent points, and 4 for distal points, demonstrating a clear preference for local treatment. The use of points increased progressively until the Ming dynasty, specifically up to the 'Bozaibang,' and then decreased, but the proportion of local points remained consistently high.

Beginning in the Ming dynasty, ST-4, ST-6, GV-26, and CV-24 emerged as the principal local points used. In the upper face region, the first point to be used was Sizhukong (TE-23) only in the Ming dynasty. For the mid face region, several points were used from the early dynasties, but their use gradually decreased after the Ming dynasty, except for ST-1 and GB-2. The lower face region showed the greatest consistency, with Dicang (ST-4), Jiache (ST-6), Shuigou (GV-26), and Chengjiang (CV-24) becoming established as the principal combination from the Ming dynasty onward.

The analysis by meridian revealed that the Stomach meridian (foot Yangming) was the most frequently used, with 61 of 112 total uses of facial points. This predominance of the Yangming meridian is consistent with the traditional Chinese medicine theory stating that 'Yangming governs the face.' Points of the Yangming meridian on the face were used in 87.5% of possible cases, demonstrating their fundamental importance in the treatment of facial palsy. For distal points, an interesting evolution was observed: initially, various meridians were used, but gradually there was a concentration on the hand Taiyin and hand Yangming meridians, culminating with the predominant use of Hegu (LI-4) in the Qing dynasty. This evolution suggests a refinement in the understanding of the principles of point selection based on meridian theory.

The frequency of individual point use showed that Dicang (ST-4) was the most used, with 18 occurrences, followed by Jiache (ST-6) with 13 occurrences and Shuigou (GV-26) with 12 occurrences. These points are all located in the lower face region, where the symptoms of facial palsy are most evident and functionally significant. From an anatomical standpoint, the most used points are located in muscles innervated by the facial nerve, particularly those involved in facial expression and oral function. Dicang (ST-4), for example, is related to the orbicularis oris, zygomaticus major, and levator anguli oris muscles, all crucial for facial symmetry and oral function.

The clinical implications of this study are significant for modern acupuncture practice. The historical analysis provides evidence of the time-tested effectiveness of specific point combinations, particularly the combination of ST-4, ST-6, GV-26, and CV-24 for facial palsy. The historical predominance of Yangming meridian points supports the modern approach of focusing on these points in treatment. The study also reveals how the understanding of facial palsy evolved from a primarily symptomatic condition to one with a more solid theoretical basis in terms of meridian theory.

The gradual decrease in the use of adjacent points over time may reflect a more refined understanding of which points are truly essential for effective treatment.