The Acupuncture Effect on Median Nerve Morphology in Patients with Carpal Tunnel Syndrome: An Ultrasonographic Study
Ural & Öztürk · Evidence-Based Complementary and Alternative Medicine · 2017
Evidence Level
MODERATEOBJECTIVE
To investigate the effect of acupuncture on the cross-sectional area of the median nerve in patients with carpal tunnel syndrome
WHO
27 women with mild-to-moderate carpal tunnel syndrome
DURATION
4 weeks of treatment
POINTS
PC-7, PC-4, PC-6, PC-8, HT-2, HT-7, HT-8, LU-9, LI-11
🔬 Study Design
Acupuncture + Splint
n=14
10 acupuncture sessions + nocturnal splint
Control
n=13
Nocturnal splint only
📊 Results in numbers
Pain reduction (VAS) - Acupuncture
Pain reduction (VAS) - Control
Median nerve area reduction - Acupuncture
Median nerve area reduction - Control
Percentage highlights
📊 Outcome Comparison
Pain Reduction (VAS)
Functional Improvement (DHI)
This study shows that acupuncture, when combined with the use of a nocturnal splint, is more effective than splinting alone for treating carpal tunnel syndrome. Acupuncture not only significantly reduced pain and improved hand function, but also decreased swelling of the median nerve, demonstrated by ultrasound.
Article summary
Plain-language narrative summary
Carpal tunnel syndrome (CTS) is the most common compression neuropathy, affecting mainly women and causing pain, numbness, and tingling in the first three or four fingers of the hand. This randomized controlled trial investigated for the first time whether acupuncture can influence not only clinical symptoms, but also median nerve morphology in patients with CTS. Twenty-seven women (totaling 45 affected limbs) with mild-to-moderate CTS were randomly divided into two groups: one group received acupuncture in addition to nocturnal splinting, while the control group used only nocturnal splints for four weeks. The acupuncture group received treatment at nine specific points (PC-7, PC-4, PC-6, PC-8, HT-2, HT-7, HT-8, LU-9, and LI-11), applied by an experienced physician for 25 minutes per session, two to three times per week, for a total of 10 sessions.
The researchers used multiple assessment tools, including the Visual Analog Scale (VAS) for pain, the Duruöz Hand Index (DHI), and the Quick DASH questionnaire for hand function, in addition to electrophysiological tests and ultrasonography to measure the cross-sectional area (CSA) of the median nerve. The results demonstrated significant improvements in both groups, but with substantial advantages for the acupuncture group. Pain reduction was notably greater in the acupuncture group (46.8% vs. 11.4%), as was functional improvement measured by the DHI (21.7% vs.
8.1%). More importantly, for the first time in the scientific literature, it was demonstrated that acupuncture significantly reduced the cross-sectional area of the median nerve (reduction of 8.1% vs. only 0.4% in the control group), indicating a real decrease in nerve swelling. Electrophysiological tests also showed greater improvements in the acupuncture group, including increases in sensory conduction velocity and improvements in action potentials.
The mechanism by which acupuncture produces these effects is not yet completely elucidated, but previous studies suggest that it may involve changes in brain activity, modulation of the limbic system, and anti-inflammatory effects that reduce inflammation in the compressed median nerve. Ultrasonography proved to be a valuable tool for monitoring treatment progress, allowing visualization of morphological changes in the nerve that correlate with clinical improvement. This study offers encouraging evidence that acupuncture not only relieves symptoms, but may promote beneficial structural changes in the affected nerve, providing a more solid scientific basis for its use in the treatment of CTS.
Strengths
- 1First study to demonstrate morphological effects of acupuncture on the median nerve
- 2Randomized controlled design with multiple assessment tools
- 3Innovative use of ultrasonography for objective monitoring
- 4Well-defined acupuncture protocol with specific points
Limitations
- 1Small sample (only 27 patients)
- 2Absence of placebo group to control for nonspecific effects
- 3Follow-up limited to 4 weeks without long-term assessment
- 4Study limited to women with mild-to-moderate CTS
Expert Commentary
Dr. Marcus Yu Bin Pai
MD, PhD · Pain Medicine · Physical Medicine and Rehabilitation · Medical Acupuncture
▸ Clinical Relevance
Carpal tunnel syndrome represents the most prevalent compressive neuropathy in rehabilitation and pain clinics, and the clinical question of when to escalate treatment beyond nocturnal splinting is encountered daily. This work by Ural and Öztürk answers that question with an outcome variable that goes beyond subjective symptoms: the cross-sectional area of the median nerve on ultrasonography. This transforms the discussion with the patient — and with the rheumatologist or hand surgeon — because we now have a morphological marker, not only a pain scale, to support the indication for acupuncture. In physiatry clinic practice, this finding justifies acupuncture as an intermediate step before considering corticosteroid injection or surgical decompression in mild-to-moderate cases, especially in women who have relative contraindications to corticosteroids or who refuse the invasive procedure.
▸ Notable Findings
The finding that deserves central attention is not the pain reduction itself — 46.8% in the acupuncture group versus 11.4% in the control after four weeks — although this absolute difference is already clinically expressive. What makes this study unique is the 8.1% reduction in the cross-sectional area of the median nerve with acupuncture, compared with virtually no morphological change in the splint-only group (0.4%). For the first time in the literature, it has been documented by imaging that acupuncture not only modulates pain perception, but promotes measurable neural deedematization. Associated with this, the electrophysiological improvements — sensory conduction velocity and amplitude of action potentials — give pathophysiological coherence to the ultrasonographic finding, suggesting that the reduction of perineural edema translates into functional recovery of nerve conduction, which is mechanistically consistent with local anti-inflammatory effects and autonomic modulation described in other acupuncture models.
▸ From My Experience
In my practice in the musculoskeletal pain clinic, I usually see symptomatic response in mild-to-moderate CTS as early as the third to fifth acupuncture session — perceptible reduction of nocturnal dysesthesia and improvement in pinch strength in the morning. I use a protocol of periradicular points at the wrist combined with distal points, very close to what is described in this article, and maintain the nocturnal splint concurrently because the synergistic effects are evident. On average, I take patients through 10 to 12 sessions before reassessing with ultrasonography and electromyography. The profile that responds best, in my experience, is the perimenopausal patient with bilateral CTS, without established thenar atrophy — exactly the mild-to-moderate spectrum of this study. When there is thenar atrophy or very prolonged motor latencies, I refer directly to surgery and do not initiate acupuncture as an attempt to delay the inevitable.
Full original article
Read the full scientific study
Evidence-Based Complementary and Alternative Medicine · 2017
DOI: 10.1155/2017/7420648
Access original articleScientific Review
Marcus Yu Bin Pai, MD, PhD
CRM-SP: 158074 | RQE: 65523 · 65524 · 655241
PhD in Health Sciences, University of São Paulo. Board-certified in Pain Medicine, Physical Medicine and Rehabilitation, and Medical Acupuncture. Scientific review and curation of every entry in this library.
Learn more about the author →Medical disclaimer: This content is for educational purposes only and does not replace consultation, diagnosis, or treatment by a qualified professional. Some information may be assisted by artificial intelligence and is subject to inaccuracies. Always consult a physician.
Content reviewed by the medical team at CEIMEC — Integrated Centre for Chinese Medicine Studies, a reference in Medical Acupuncture for over 30 years.
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