Early intervention with acupuncture improves the outcome of patients with Bell's palsy: A propensity score-matching analysis

Bell's palsy is a common neurological condition that affects approximately 11.5 to 40.2 people per 100,000 inhabitants, causing unilateral facial weakness or paralysis due to acute peripheral facial nerve dysfunction. Although about 70% of patients recover spontaneously, approximately 30% develop permanent sequelae such as residual paresis, contracture, and synkinesis, significantly impacting social and psychological function. This Chinese retrospective study investigated whether the timing of acupuncture initiation influences treatment outcomes in Bell's palsy. The research included 345 patients diagnosed between 2016 and 2021, divided into two groups: those who received acupuncture within the first 7 days (early MA/EA group, n=76) and those who began after this window (late EA group, n=125).

To ensure valid comparisons, the researchers used propensity score matching (PSM), an advanced statistical technique that balanced characteristics such as age, sex, comorbidities, and time to initiation of pharmacological treatment between the groups. After matching, 61 patients from each group were analyzed. The treatment protocol differed according to timing: patients treated early received gentle manual acupuncture during the first 7 days, avoiding electrical stimulation that could aggravate neural edema, followed by electroacupuncture. The late group received only conventional electroacupuncture at 20 Hz.

All patients also received prednisolone following standard Chinese guidelines. The results demonstrated significant benefits from early intervention. The mean time to complete recovery was substantially shorter in the early group (36.62 ± 4.78 vs 55.40 ± 6.93 days, p < 0.05), with a hazard ratio of 1.505 (95% CI 1.028-2.404), indicating a 50% higher probability of faster recovery. At 12 weeks, 93.4% of patients in the early group achieved complete recovery versus 80.3% in the late group (p = 0.032).

At 24 weeks, sequelae occurred in only 6.6% of patients treated early compared with 16.4% in the late group, although this difference did not reach statistical significance (p = 0.088). The mechanisms proposed for these benefits include the anti-inflammatory effects of acupuncture, similar to corticosteroids, possibly mediated by activation of the vagal-adrenal axis. The early therapeutic window may be crucial, as observed with corticosteroids, whose benefits diminish after 72 hours of symptom onset. Treatment safety was satisfactory, with mild and transient adverse events in 6.6% of the early group versus 3.3% of the late group (p > 0.05), including subcutaneous hemorrhage, acute post-needling pain, and fainting during treatment.

This study represents an important advance in understanding the optimal timing for acupuncture in Bell's palsy, providing robust evidence through PSM methodology to minimize confounding biases. The clinical implications are significant, suggesting that acupuncture should be considered as early complementary therapy, potentially changing treatment protocols to maximize recovery and minimize permanent sequelae.