Efficacy and Safety of Acupuncture Combined with Chinese Herbal Fumigation in the Treatment of Chronic Non-Specific Neck Pain: A Study Protocol for a Multicenter Randomized Controlled Trial

Background Chronic non-specific neck pain is a common musculoskeletal disorder and one of the leading causes of disability worldwide. Conventional treatments have limited efficacy and may be associated with adverse effects. Acupuncture and Chinese herbal fumigation are commonly used therapies in traditional Chinese medicine and have demonstrated potential analgesic and functional improvement effects. However, high-quality randomized controlled trials evaluating the efficacy of the combination of these two therapies are lacking. This study aims to assess the efficacy and safety of acupuncture combined with Chinese herbal fumigation in the treatment of chronic non-specific neck pain. Methods This study is a multicenter, randomized, parallel three-arm controlled clinical trial. A total of 120 patients with chronic non-specific neck pain will be enrolled and randomly allocated to three groups: acupuncture combined with Chinese herbal fumigation group, acupuncture combined with sham fumigation group, and acupuncture alone group. An assessor-blind design will be adopted to reduce bias. All participants will receive five treatment sessions within three weeks, with a follow-up conducted four weeks after the final treatment. The intervention group will receive acupuncture combined with Chinese herbal fumigation, utilizing the Wenyang Tongluo Fumigation Formula for the fumigation procedure. The acupuncture combined with sham fumigation group will undergo fumigation using liquid water without any herbal components, administered under identical temperature and duration conditions. The acupuncture alone group will receive only acupuncture treatment. Bilateral cervical Jiaji points (EX-B2) will be used as the primary acupoints. The primary outcome measure is pain intensity assessed using the Visual Analog Scale (VAS). Secondary outcome measures include the Neck Disability Index (NDI), cervical range of motion, quality of life scale, Pittsburgh Sleep Quality Index (PSQI), and Central Sensitization Inventory (CSI). Outcome assessments will be conducted at baseline, immediately after the first treatment, immediately after the fifth treatment, and at the four-week follow-up after the final treatment. Statistical analysis will be performed using SPSS 26.0 software, employing a mixed-design analysis. Efficacy evaluations will be conducted based on the intention-to-treat (ITT) principle, including all randomized participants. For continuous data conforming to a normal distribution, independent sample t-tests or repeated measures analysis of variance (ANOVA) will be used; non-normally distributed data will be analyzed using nonparametric tests. Categorical data will be analyzed using chi-square tests. A statistical significance level of ( P < 0.01 ) will be adopted. Adverse events will be continuously monitored throughout the study, and an emergency response plan will be established to ensure scientific rigor and ethical compliance. Results Based on preliminary clinical speculation, all three treatment groups are expected to show significant improvements in the primary outcome measure and several secondary outcome measures compared to baseline. The acupuncture combined with Chinese herbal fumigation group is predicted to demonstrate significantly superior immediate efficacy and long-term efficacy at the four-week follow-up compared to both the acupuncture combined with sham fumigation group and the acupuncture alone group ( P < 0.01 ). In terms of immediate efficacy, the acupuncture combined with sham fumigation group is expected to show greater improvement than the acupuncture alone group ( P < 0.01 ); however, at the follow-up assessment, the difference between these two groups is no longer expected to be significant ( P > 0.01 ). Discussion Based on the anticipated findings of this study, it can be concluded that acupuncture combined with Chinese herbal fumigation, acupuncture combined with sham fumigation, and acupuncture alone can each improve pain levels and related functions in patients with chronic non-specific neck pain to varying degrees. The thermal stimulation, improved local blood circulation, and psychological sham effects associated with the fumigation process may contribute to short-term symptom relief. The addition of herbal components may further enhance treatment efficacy and prolong the duration of therapeutic effects, suggesting that herbal ingredients play a significant role in achieving sustained therapeutic outcomes. From the perspective of traditional Chinese medicine, chronic non-specific neck pain is often attributed to “cold coagulation in the meridians and qi-blood stagnation,” and the treatment principle should focus on warming yang, dispersing cold, activating blood, and unblocking meridians. The Wenyang Tongluo Fumigation Formula employed in this study has the effects of warming the meridians, dispersing cold, relaxing sinews, and unblocking collaterals. Through thermal steam, the active herbal ingredients are absorbed transdermally, which not only improves local tissue blood circulation but also alleviates muscle tension and inflammatory responses, thereby enhancing the analgesic and meridian-unblocking effects of acupuncture. This may, to some extent, explain the comprehensive advantages of combination therapy in pain relief, functional improvement, and quality of life enhancement. Additionally, this study adopts a multidimensional evaluation system that not only observes pain intensity but also comprehensively assesses cervical function, range of motion, quality of life, sleep quality, and central sensitization, providing a more holistic reflection of the treatment’s impact on patients’ overall health status.