Effectiveness and safety of acupuncture for post-stroke spasticity: A systematic review and meta-analysis

Post-stroke spasticity represents one of the most challenging complications faced by patients and families during the recovery process. This condition, characterized by increased muscle tension and stiffness in the affected limbs, can affect between 30% and 80% of stroke survivors, significantly impacting movement capacity, performance of daily activities, and quality of life. Beyond the personal suffering, spasticity carries significant economic consequences, with direct costs that can be four times higher during the first year after stroke. Given the limitations of conventional treatments — such as physical therapy, oral medications, and botulinum toxin injections, which may have limited efficacy or significant side effects — there is growing interest in complementary therapies such as acupuncture, an ancient practice of traditional Chinese medicine known for its safety and pragmatic effectiveness.

This systematic review and meta-analysis, conducted by Chinese researchers and published in August 2022, aimed to comprehensively evaluate the effectiveness and safety of acupuncture in the treatment of post-stroke spasticity. The researchers conducted an extensive search across nine electronic databases, from inception through June 2022, looking for randomized clinical trials investigating the use of acupuncture for this condition. The methodology rigorously followed international standards for systematic reviews, including independent assessment by multiple reviewers, analysis of the risk of bias of the studies, and assessment of the quality of evidence according to established criteria. The review included different modalities of acupuncture, such as manual acupuncture, electroacupuncture, scalp acupuncture, and eye acupuncture, comparing them with conventional rehabilitation, sham acupuncture, or Western medications.

The results of this broad investigation were promising and statistically significant. The analysis included 88 studies involving 6,431 patients, demonstrating that acupuncture combined with conventional rehabilitation was superior to rehabilitation alone in reducing scores on the Modified Ashworth Scale, the main instrument used to measure spasticity. The effect size observed was clinically relevant, suggesting that the difference found has practical meaning for patients. When compared in isolation with conventional rehabilitation, acupuncture also showed benefits, although with smaller magnitude.

Subgroup analyses revealed important findings: treatments performed once or twice daily were more effective than once every other day, and the antispastic effect of acupuncture increased with a greater number of sessions, suggesting a cumulative effect. Both manual acupuncture and electroacupuncture demonstrated benefits, and the positive effects were observed in both upper and lower limbs. In addition to spasticity reduction, acupuncture combined with conventional rehabilitation also improved motor function and activities of daily living.

For patients and families, these results offer hope and a promising additional therapeutic option. Acupuncture may be considered a safe complementary therapy alongside conventional treatment for post-stroke spasticity, potentiating the benefits of traditional rehabilitation. The findings suggest that more frequent and longer-duration treatments may yield better outcomes, valuable information for therapeutic planning. For health care professionals, the study provides scientific evidence that may guide clinical decisions, especially considering that only four studies reported mild adverse events related to acupuncture, such as small hematomas or syncope, confirming the technique's favorable safety profile.

The benefits observed were not limited to reduction of muscle stiffness but extended to improvement in motor function and ability to perform daily activities, fundamental aspects for patient independence and quality of life.

Despite the encouraging results, it is important to acknowledge the significant limitations of this research. Most included studies had a high risk of methodological bias, primarily due to inadequate blinding of assessors and patients, a common issue in acupuncture studies because of the difficulty of creating truly blinded control groups. Furthermore, there was considerable heterogeneity across studies in the acupuncture protocols used, the populations studied, and the assessment methods, which may have influenced the results. Overall quality of evidence was considered low to moderate, indicating that future research may substantially modify the effect estimates.

The possible existence of publication bias was also identified, suggesting that studies with negative results may not have been published. These factors require caution in interpreting the results and highlight the need for future studies with greater methodological rigor, including better standardization of acupuncture protocols, use of appropriate control groups, and assessment of long-term effects to establish more definitively the role of acupuncture in the treatment of post-stroke spasticity.