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作者：Susan Jeffrey  
出處：WebMD醫學報導

　　December 31, 2009 — 美國神經科學院的最新版實證回顧結論指出，不建議使用「經皮神經電刺激(transcutaneous electric nerve stimulation，TENS)」用於慢性下背痛的治療，另外，指出應考慮以TENS於治療糖尿病神經病變。
　　
　　該學院的治療與科技評估小組委員會發表的此一報告，線上登載於12月30日的神經學(Neurology)期刊。新版指引的作者包括堪薩斯市堪薩斯大學醫學中心的Richard M. Dubinsky醫師，以及加拿大安大略省多倫多西部醫院的Janis Miyasaki醫師。
　　
　　Dubinsky醫師向Medscape Neurology表示，在慢性下背痛的最高品質研究中，相較於假裝給予TENS(安慰劑組)，TENS並沒有幫助，我們因而結論認為它沒有幫助，提出不應用於慢性下背痛的建議。
　　
　　他指出，至於糖尿病多發性神經病變，有些研究顯示有效，我們的結論認為，可以考慮用它治療糖尿病多發性神經病變。
　　
　　【系統性回顧】
　　作者們寫道，TENS已經被用於治療神經和其他疾患數十年，其止痛效果的生物基礎未知，而是利用疼痛的門閘學說進行治療。此次評估中，作者們在Medline和Cochrane Library進行至2009年4月止的系統性文獻搜尋，聚焦在以TENS治療神經相關疼痛的臨床控制試驗。
　　
　　神經疾患中一般不會出現的急性下背痛未被納入此次回顧。除了一篇之外，所有研究排除已知的下背痛原因，如根神經病變(pinched nerves)、嚴重脊椎側彎、嚴重脊椎滑脫(spondylolisthesis) 或肥胖的病患。
　　
　　Dubinsky醫師表示，我們只有發現兩個適合此研究的狀況，也就是慢性背痛和糖尿病多發性神經病變。
　　
　　納入的研究在慢性下背痛方面的結果互異，兩篇等級2的研究顯示有幫助，但是兩篇等級1的研究與另外一篇等級2的研究顯示沒有幫助。他們寫道，因為等級1研究的證據力較強，TENS被視為對於治療慢性下背痛沒有效果。
　　
　　兩篇等級2的研究認為TENS在治療疼痛性糖尿病神經病變可能有效。這類TENS研究中唯一提出與慢性下背痛有關的神經原因是多發性硬化症，而TENS對其無效。
　　
　　該報告提出的兩個主要建議：
　　* 不建議以TENS用於治療慢性下背痛，因為缺乏有效的證據(等級A，兩篇等級1研究)。
　　* 可以考慮以TENS用於治療疼痛性的糖尿病神經病變(等級B，兩篇等級2研究)。
　　
　　Dubinsky醫師指出，該報告也提出一些關於TENS後續研究的指引，在他們的建議中，根據電流、脈衝寬度和頻率，確認最佳的治療方式，用於未曾使用TENS的病患， 以讓他們真的對所分派的治療方式不知情，以及研究TENS用於已經確立之神經疾患的病患。
　　
　　【缺乏證據】
　　德國Christian-Albrechts- Kiel大學神經科、神經疼痛研究與治療小組的Andreas Binder醫師與Ralf Baron醫師在編輯評論中寫道，Dubinsky醫師與Miyasaki醫師的結論有助於熱絡關於TENS的可用性的討論，也可視為支持「懷疑TENS用於疼痛治療之價值」的論述。
　　
　　不過，他們指出，缺乏證據不是沒有證據，統合分析的臨床影響往往受到納入試驗之質量的影響。
　　
　　TENS在疼痛處置上有著由來已久的角色，容易掌控、可接受之利益風險比、無效時可以立即停用，他們寫道，這些都是疼痛治療的必要性質，新版指引也呼籲進行後續試驗，且提出了相關的明確建議。
　　
　　Binder醫師及Baron醫師結論表示，這篇新版的實證回顧在有限的實證基礎上提供其價值，然而，即使相對的科學與臨床證據較弱，認為TENS有用的立場也並非不合理，TENS依舊是神經疼痛異常一個有價值的替代療法。
　　
　　相較於其他疼痛緩解方法，TENS有可接受的利益風險比，TENS依舊是各種疼痛治療方式中有用的一種。
　　
　　Dubinsky醫師擔任Allergan Inc的科學諮詢委員與發言人、接受BrioMed的獎助金、接受Allergan公司、Merz Pharmaceuticals GmbH以及國家健康研究中心、NIAM/國家神經異常與中風研究中心、國家輔助療法及另類醫學研究中心等之研究支持，他太太擁有Abbott的股權。共同作者的宣告登載於文中。Binder 醫師接受非業界資助的演講與教育活動差旅費，接受Grunenthal、Allergan Inc與Pfizer Inc等之發言合約與教育活動獎助金。Baron醫師擔任Pfizer、Genzyme Corporation、Grunenthal、Mundipharma International、Allergan、Sanofi Pasteur、Medtronic、Eisai 、UCB、Eli Lilly and Company與Astellas Pharma Inc等之科學諮詢委員、顧問與發言人；接受非業界資助的演講與教育活動差旅費；擔任Pain期刊的副編輯與Nature Reviews Neurology期刊和European Journal of Pain期刊的編輯委員；接受Pfizer、Genzyme Corporation、AGrunenthal、the German Ministry of Research以及DFG、Deutsche Forschungsgemeinschaft等之研究支持。
　　
　　Neurology. 線上登載於2009年12月30日。


AAN Guideline Recommends Against TENS for Chronic Low-Back Pain

By Susan Jeffrey
Medscape Medical News

December 31, 2009 — A new evidence-based review from the American Academy of Neurology concludes that transcutaneous electric nerve stimulation (TENS) is not recommended for use in treating chronic low-back pain but adds that TENS should be considered to treat diabetic neuropathy.

The report, from the academy's Therapeutics and Technology Assessment Subcommittee, was published online December 30 in Neurology. Authors on the new document are Richard M. Dubinsky, MD, MPH, from Kansas University Medical Center in Kansas City, and Janis Miyasaki, MD, MEd, from Toronto Western Hospital, Ontario, Canada.

"In the highest-quality studies of chronic low back pain, there was no benefit of TENS compared to sham or placebo TENS, leaving us to conclude that it is of no benefit, and make a recommendation that it should not be used for chronic low back pain," Dr. Dubinsky told Medscape Neurology.

In diabetic polyneuropathy, some studies showed slight benefit, he added. "We concluded it should be considered in the treatment of diabetic polyneuropathy."

Systematic Review

TENS has been used to treat neurologic and other disorders for decades, the authors write. The biologic basis of its analgesic effect is not known, but it is used is based on the gate theory of pain, they note. In this assessment, the authors carried out a systematic literature search of Medline and Cochrane Library up to April 2009, looking for controlled clinical trials in which TENS was used to treat pain associated with neurological conditions.

Acute low back pain not normally seen in neurologic conditions was not considered in this review. All but 1 of the studies excluded patients with known causes of low-back pain, such as pinched nerves, severe scoliosis, severe spondylolisthesis, or obesity.

"We only found 2 conditions that had adequate rigor in the research, and that was chronic back pain and diabetic polyneuropathy," Dr. Dubinsky said.

The studies included showed conflicting results in chronic low back pain. Two class 2 studies showed benefit, but 2 class 1 studies and another class 2 study showed no benefit. "Because the Class I studies are stronger evidence, TENS is established as ineffective for the treatment of chronic low back pain," they write.

Two class 2 studies suggested that TENS is probably effective in treating painful diabetic neuropathy. The only specific neurologic cause of chronic low-back pain in which TENS was studied was multiple sclerosis, for which TENS was not shown to be of benefit.

The document makes 2 main recommendations:

TENS is not recommended for the treatment of chronic low-back pain because of a lack of proven efficacy (level A, 2 class 1 studies).
TENS should be considered for the treatment of painful diabetic neuropathy (level B, 2 class 2 studies).
The document also gives some guidance on the need for further research into TENS, Dr. Dubinsky noted. Among their recommendations were determining what the best paradigm is, in terms of current, pulse-width, and frequency, and then using it in patients who are naive to TENS so that they will be truly blinded to treatment allocation, and studying TENS in patients with well-defined neurological conditions.

Absence of Evidence

In an editorial accompanying the new document, Andreas Binder, MD, and Ralf Baron, MD, from the Division of Neurological Pain Research and Therapy in the Department of Neurology at Christian-Albrechts-Universitat Kiel, Germany, write that the conclusions of Dr. Dubinsky and Dr. Miyasaki "may heat up the discussion on the usability of TENS and may be viewed as supporting the critics who questioned the value of TENS in pain therapy.

"However," they add, "absence of evidence is not evidence of absence. The clinical impact of meta-analyses is always limited by the quantity and quality of conducted trials."

TENS has had a long-standing role in pain management, is easy to handle, has a favorable benefit-to-risk ratio, and can be discontinued easily if it is not efficacious — all "desirable properties when treating pain," they write. The new document calls for further trials and even provides "clearcut recommendations for their conduction," they note.

"This updated evidence-based review is valuable in providing the limits of our evidence base," Dr. Binder and Dr. Baron conclude. "Nevertheless, it is not unreasonable to take a practical position that, in spite of the relatively weak scientific and clinical evidence, TENS still represents a valuable therapeutic alternative in neurologic pain disorders.

"Taking the favorable benefit-risk ratio when compared with other pain relieving methods into account, TENS remains a valuable part in the armamentarium of pain therapy."

Dr. Dubinsky serves on a scientific advisory board and speakers' bureau for Allergan Inc, receives honoraria from BrioMed, and receives research support from Allergan Inc, Merz Pharmaceuticals GmbH, and the National Institutes of Health, the NIAM/National Institute of Neurological Disorders and Stroke, and the National Center for Complementary and Alternative Medicine, and his spouse owns stock in Abbott. Disclosures for coauthors appear in the paper. Dr. Binder has received travel expenses for lectures and educational activities not funded by industry and has received honoraria for speaking engagements and educational activities from Grunenthal, Allergan Inc, and Pfizer Inc. Dr. Baron serves on scientific advisory boards, as a consultant, and on speakers' bureau for Pfizer Inc, Genzyme Corporation, Grunenthal, Mundipharma International, Allergan Inc, Sanofi Pasteur, Medtronic Inc, Eisai Inc, UCB, Eli Lilly and Company, and Astellas Pharma Inc; has received travel expenses for lectures or educational activities not funded by industry; serves as an associate editor of Pain and on the editorial advisory boards of Nature Reviews Neurology and the European Journal of Pain; and has received research support from Pfizer Inc, Genzyme Corporation, Grunenthal, the German Ministry of Research, and DFG, Deutsche Forschungsgemeinschaft.

Neurology. Published online December 30, 2009.