Electroacupuncture with intradermal needles for Bell's palsy shows no overall benefit but may help severe cases

OBJECTIVES: To investigate the clinical efficacy of electroacupuncture (EA) combined with intradermal acupuncture (IA) for Bell's palsy (BP) based on the stratification of facial paralysis (FP) severity. METHODS: A total of 220 patients with BP were stratified according to FP severity (House-Brackmann Facial Nerve Grading System) and enrolled. They were randomly divided into an observation group (moderate BP 55 cases [5 cases dropped off], severe BP 55 cases [3 cases dropped off]) and a control group (moderate BP 55 cases [1 case dropped off], severe BP 55 cases [3 cases dropped off]). The control group received traditional EA. Main acupoints included Yifeng (SJ17), Dicang (ST4), Jiache (ST6), Yangbai (GB14), Xiaguan (ST7), Qianzheng (EX-HN16) on the affected side, and bilateral Hegu (LI4). Electrical stimulation was applied to two pairs of acupoints (ST6 and ST4, SJ17 and ST7) for 30 min per session. The observation group received IA in addition to the same EA treatment as the control group. After each EA treatment, IA was applied to the main acupoints. Patients were instructed to press the embedded needles three times daily. IA was retained for 24 h and then removed. Treatment for both groups commenced on the 8 day after the onset, once every other day, three times per week until complete recovery or the end of the 24-week follow-up period. The recovery time of the two groups was observed. The cure rates at weeks 6, 12, and 24 were compared between groups. The surface electromyography (sEMG) of the affected-side facial expression muscle groups was assessed at the baseline and week 12. The incidence of synkinesis at week 24 was compared between the two groups. All indicators were analyzed for the total sample overall and by FP severity stratum. RESULTS: ①When the total sample was analyzed, the root mean square (RMS) ratios of facial expression muscle groups increased from baseline to week 12 in both groups (<0.01). However, there were no significant between-group differences in cure rates at weeks 6, 12, and 24, recovery time, the incidence of synkinesis at week 24. ②For patients with severe BP:The cure rates in the observation group were significantly higher than those in the control group at weeks 6, 12 and 24 (<0.05). Survival analysis indicated a shorter recovery time in the observation group (<0.05). At week 12, the RMS ratios in the observation group were also higher than those in the control group (<0.05). The difference in the incidence of synkinesis at week 24 between the two groups was not statistically significant. ③For patients with moderate BP:No statistically significant differences were observed between the two groups regarding cure rates at weeks 6, 12, and 24, recovery time, facial expression muscle RMS ratios at week 12, and synkinesis incidence at week 24. CONCLUSIONS: The clinical efficacy of EA combined with IA in treating severe BP (House-Brackmann grades Ⅴ/Ⅵ) is superior to that of single EA. The combined therapy can significantly improve the cure rate, shorten recovery time, and improve the muscle strength of the facial expression muscles, without increasing the incidence of synkinesis. Conversely, for moderate BP (House-Brackmann grades Ⅲ/Ⅳ), the combined therapy does not show superiority over single EA.