Effectiveness of Acupuncture for Katakori (Nonspecific Neck and Shoulder Stiffness/Tightness): A Systematic Review and Meta-Analysis

Abstract Background Katakori refers to discomfort or dull pain around the back of the head and through the shoulders and/or shoulder blades in Japanese. It is often translated as “neck and shoulder pain” or “nonspecific neck pain,” but it is considered a culturally specific symptom that is especially prevalent in Japan. It significantly affects quality of life and labor productivity. However, standard treatments have not been established. This study aimed to evaluate the effectiveness of acupuncture for Katakori. Methods We conducted a systematic review and meta-analysis of relevant randomized controlled trials (RCTs) and quasi-RCTs on acupuncture for primary Katakori in adults according to the PRISMA 2020 guidelines. We searched PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Ichushi-Web for relevant articles published up to March 7, 2025. We also explored Evidence Reports of Japanese Acupuncture and Moxibustion, ClinicalTrials.gov, the International Clinical Trials Registry Platform, Japan Primary Registries Network, and our proprietary files. The risk of bias was assessed using the Cochrane Risk of Bias 2 tool. The data were synthesized using a random-effects model and are presented as forest plots (PROSPERO: CRD42021254975). Results Fourteen studies involving 831 participants were included in this review. The certainty of evidence was rated as very low due to the risk of bias and imprecision. Manual acupuncture was not associated with significant improvements in subjective Katakori symptoms relative to sham acupuncture. However, it was more effective than non-penetrating sham acupuncture for improving Katakori at the end of the treatment period (mean difference, −12.89 [95% confidence interval: −22.60 to −3.17]) when the sham controls were categorized into shallow-penetration and non-penetration subgroups. Conclusion The findings of this study suggest that acupuncture may be more effective than non-penetrating sham controls for alleviating the subjective symptoms of Katakori. However, definitive conclusions cannot be drawn due to the very low certainty of evidence. The findings should be interpreted with caution given the small sample sizes. Large-scale RCTs with rigorous designs are needed to establish the clinical effectiveness of acupuncture for Katakori. Graphical Abstract