Electrical Stimulation Therapy and Home Devices
This Coverage Policy addresses outpatient electrical simulation therapy (i.e., wound care therapy, auricular
electroacupuncture, transcutaneous electrical modulation pain reprocessing) and the use of in-home devices,
conductive garments and other related supplies for the treatment of multiple conditions.
Electrical Stimulation Therapies
Chronic Wound Healing
Electrical stimulation (HCPCS Code G0281) is considered medically necessary for the treatment of a
chronic wound when ALL of the following criteria are met:
• Presence of ANY of the following chronic wound types:
Stage 3 or stage 4 pressure ulcer
neuropathic (diabetic) ulcer
venous stasis ulcer
• Failure to demonstrate measurable signs of improved healing (e.g., signs of epithelialization and
reduction in ulcer size) with a 30-day trial of conventional wound management, including optimization of
nutritional status, moist dressings and debridement.
• Electrical stimulation therapy is performed under the direct supervision of a medical professional with
expertise in wound evaluation and management.
The use of electrical stimulation in the home setting for wound healing in the absence of direct
supervision by a health care provider is considered experimental, investigational or unproven.
Electrical stimulation therapy for any other chronic wound indication including but not limited to
prevention of a pressure ulcer or pressure sore is considered experimental, investigational or unproven.
Other Electrical Stimulation Therapies
Each of the following electrical stimulation therapies is considered experimental, investigational or
• auricular electroacupuncture (e.g., PStim™) (HCPCS Code S8930)
• transcutaneous electrical modulation pain reprocessing (TEMPR) (e.g., Scrambler therapy,
Home Electrical Stimulation Devices (Electrical Stimulators)
Coverage for Durable Medical Equipment (DME) including in-home electrical stimulation devices varies
across plans. Please refer to the customer’s benefit plan document for coverage details.
If coverage for an in-home electrical stimulation device is available, the following conditions of coverage
Neuromuscular Electrical Stimulation (NMES)
Neuromuscular electrical stimulation (NMES) (HCPCS Code E0745) and related supplies (HCPCS Code
A4595) are considered medically necessary when used as one component of a comprehensive
rehabilitation program for the treatment of disuse atrophy when the nerve supply to the atrophied
muscle is intact.
Neuromuscular electrical stimulation (NMES) and related supplies (HCPCS Code A4595) for ANY other
indication (e.g., idiopathic scoliosis [HCPCS Code E0744], heart failure) are considered experimental,
investigational or unproven.
Transcutaneous Electrical Nerve Stimulation (TENS)
A transcutaneous electrical nerve stimulator (TENS) (HCPCS Code E0720, E0730) and related supplies
(HCPCS Code A4595) are considered medically necessary for in-home use as an adjunct to conventional
post-operative pain management within 30 days of surgery.
TENS (HCPCS Code E0720, E0730) and related supplies (HCPCS Code A4595) for ANY other indication,
including a device for the treatment of migraine headaches (e.g., Cefaly), are considered experimental,
investigational or unproven.
A conductive garment (HCPCS Code E0731) is considered medically necessary when used in
conjunction with a medically necessary in-home NMES or TENS device for ANY of the following clinical
• The use of conventional electrodes, tapes or lead wires is not feasible either because the individual has
a large area requiring treatment or a large number of sites requiring stimulation.
• The site(s) requiring stimulation (i.e., back) is/are difficult to reach with conventional electrodes, tapes or
• A co-existing medical condition (e.g., skin problems) precludes the use of conventional electrodes,
tapes, or lead wires.
A conductive garment for any other in-home indication is considered not medically necessary.
Other Electrical Stimulation Devices
In-home use of ANY of the following electrical stimulation devices is considered experimental,
investigational, or unproven for the treatment of any condition:
• bioelectric nerve block (electroceutical therapy) (HCPCS Code E1399)
• cranial electrical stimulation (cranial electrotherapy stimulation) (HCPCS Code E1399)
• electrical sympathetic stimulation therapy (HCPCS Code E1399)
• electrotherapeutic point stimulation (ETPSSM) (HCPCS Code E1399)
• functional electrical stimulation (FES) (HCPCS Codes E0764, E0770)
• H-WAVE electrical stimulation (HCPCS Code E1399)
• high-voltage galvanic stimulator (HVG) (HCPCS Code E1399)
• interferential therapy (IFT) (HCPCS Codes S8130, S8131)
• microcurrent electrical nerve stimulation (MENS), including frequency-specific microcurrent (FSM)
stimulation (HCPCS Code E1399)
• pelvic floor electrical stimulation (PFES) (HCPCS Code E0740)
• percutaneous electrical nerve stimulation (PENS) (HCPCS Code E1399)
• percutaneous neuromodulation therapy (PNT) (HCPCS Code E1399)
• percutaneous nerve field stimulator (PNFS) (e.g., NSS-2 Bridge) (HCPCS Code E1399)
• threshold/therapeutic electrical stimulation (TES) (HCPCS Code E1399)
• transcutaneous electrical acupoint stimulation (TEAS) (HCPCS Code E0765)
• transcutaneous electrical joint stimulation (HCPCS Code E0762)
Note: For electrical stimulation therapies in the outpatient setting please refer to the Cigna/American
Specialty Health (ASH) Coverage Policy “Electric Stimulation for Pain, Swelling and Function in a
Electrical stimulation (ES) therapy involves the application of electrodes to affected areas of the body for the
purpose of delivering electrical current. ES is used for neuromuscular relaxation and contraction and for wound
healing. ES devices (e.g., transcutaneous electrical stimulators [TENS]) are devices proposed for use by the
patient at home. There are numerous ES devices and proposed indications.
Electrical Stimulation Therapy
Chronic wounds, also known as ulcers, are wounds that have not completed the healing process in the expected
time frame, usually 30 days, or have proceeded through the healing phase without establishing the expected
functional results. These wounds generally do not heal without intervention and are sometimes unresponsive to
conventional therapies. Neuropathic diabetic foot ulcers, pressure ulcers, venous leg ulcers, and arterial ulcers
are examples of chronic wounds. Electrical stimulation (ES) has been proposed as an adjuvant therapy in the
treatment of stage 3 and stage 4 pressure ulcers, arterial ulcers, neuropathic (diabetic) ulcers and venous stasis
ulcers that are nonresponsive to conventional therapies.
Studies have not adequately evaluated the safety and effectiveness of unsupervised home use of electrical
stimulation devices by a patient for the treatment of chronic wounds. Risks are uncommon but may occur with
unsupervised treatments, including rashes at the site of electrode placement or, in rare cases, burns on the skin.
Evaluation of the wound is an integral part of wound therapy. It is recommended that when ES is used as an
adjunctive treatment for chronic wound healing, treatment should be conducted under the direct supervision of a
medical professional with expertise in wound evaluation and management (Centers for Medicare and Medicaid
A pressure ulcer, also known as a decubitus ulcer or bedsore, is the result of pathologic changes in blood supply
to the dermal and underlying tissues, usually because of compression of the tissue over a bony prominence,
such as the sacrum, heels, hips and elbows (Thomas, 2011, CMS, 2002).
When evaluating pressure ulcers, a staging system is typically used that measures tissue destruction by
classifying wounds according to the tissue layers involved. In 2016, the National Pressure Ulcer Advisory Panel
(NPUAP) updated the stages of pressure ulcers. The stages that are supported by the literature for use of
electrical stimulation when conventional therapies fail are stages 3 and 4 which are described as follows:
• Stage 3: Pressure Injury: Full-thickness skin loss: Full thickness loss of skin in which adipose (fat) is
visible in the ulcer and granulation tissue and epibole (rolled wound edges) are often present. Slough
and/or eschar may be visible. The depth of tissue damage varies by anatomical location; areas of
significant adiposity can develop deep wounds. Undermining and tunneling may occur. Fascia, muscle,
tendon, ligament, cartilage and/or bone are not exposed. If slough or eschar obscures the extent of
tissue loss this is an Unstageable Pressure Injury.
• Stage 4: Pressure Injury: Full-thickness skin and tissue loss: Full thickness tissue loss with exposed or
directly palpable fascia, muscle, tendon, ligament, cartilage or bone in the ulcer. Slough or eschar may
be present. Epibole (rolled edges), undermining and/or tunneling often occur. Depth varies by
anatomical location. If slough or eschar obscures the extent of tissue loss this is an Unstageable
Arterial (ischemic) ulcers of the lower limb are caused by inadequate arterial blood supply resulting in tissue
ischemia and necrosis. Arterial ulcers may be associated with conditions such as arteriosclerosis obliterans,
thromboangiitis obliterans (Buerger’s disease), necrotizing vasculitides (e.g., polyarteritis nodosa, rheumatoid
arthritis, systemic lupus), sickle cell anemia and diabetes mellitus. Reestablishment of an adequate vascular
supply is a key factor to support proper healing. Medical management includes control of diabetes, control of
hypertension, smoking cessation, and moderate exercise (CMS, 2002; Bello, 2000).
Venous stasis ulcers result from venous hypertension, which is usually caused by valvular incompetence or can
develop as a result of thrombosis, obstruction, dilation (varicosities) or hemorrhage. The underlying
pathophysiology is venous insufficiency. Treatment regimens focus on increasing venous return and decreasing
edema. Generally treatment consists of compression stockings or wraps, combined with frequent elevation of the
extremity and avoidance of prolonged standing (Burns, et al., 2007).
The major contributors to the formation of diabetic ulcers include neuropathy, foot deformity and ischemia. The
neuropathy, both sensory and motor, is secondary to persistently elevated blood glucose levels. Therefore,
maintaining optimal blood sugar levels is important. Treatment options include antibiotics if osteomyelitis is
present, relief of pressure at the wound site, surgical debridement, control of infection, and arterial
reconstruction. Other therapeutic options may include Becaplermin (Regranex®), bioengineered skin substitutes
and a variety of synthetic dressings (Barbul, 2005).
U.S. Food and Drug Administration (FDA): According to the Centers for Medicare & Medicaid Services (CMS)
decision memorandum (2002), the FDA granted premarket application (PMA) approvals for electrical stimulators
as Class III devices for the indications of bone stimulation and deep brain stimulation. FDA has also cleared
electrical stimulators as Class II devices when indicated for muscle stimulation. However, the FDA has not
cleared or approved the use of ES for the treatment of wounds. The FDA concluded that the use of these
devices for the treatment of wounds is significantly different than the use of these devices for the indications
currently covered under a 510(k) clearance. They are considered Class III devices and, as such, require
approval via the PMA process. Manufacturers cannot market electrical stimulators for wound healing. However,
lack of approval does not preclude physicians and other healthcare providers from providing this therapy as an
Literature Review: ES is an established treatment option for chronic stage 3 and stage 4 pressure ulcers,
venous stasis ulcers, arterial ulcers, and neuropathic diabetic foot ulcers. Although there is a limited number of
studies investigating ES for the treatment of chronic wounds, meta-analysis (n=12 studies), systematic reviews,
randomized controlled trials (n=34–63) and a nonrandomized comparative study (n=80) reported significant
improvement in healing and decrease in wound size or complete healing compared to placebo or no stimulation.
Follow-ups occurred for up to three months. There is high variability as to which type of electrical current and
application protocol is the most effective for the ulcer type (Smith, et al., 2013; Houghton, et al., 2010; Regan, et
al., 2010; Jünger, et al., 2008; Janković, et al. 2008; Adunsky, et al., 2005; Houghton, et al., 2003; Akai, et al.,
2002; Peters, et al.; 2001).
Professional Societies/Organizations: Based on a systematic review of the literature, the American College of
Physicians developed a 2015 clinical practice guideline on the treatment of pressure ulcers. The Society stated
that moderate-quality of evidence showed that electrical stimulation when used as an adjunctive therapy
accelerated wound healing when compared with sham treatment, but no evidence was found for improved
complete wound healing. “Low-quality” evidence showed that electrical stimulation had similar effect in patients
with spinal cord injuries compared with other patients and that adverse events (e.g., skin irritation) were more
common in elderly patients than younger patients (Qaseem, et al., 2015).
The American College of Foot and Ankle Surgeons (ACFA) (2006) Clinical Consensus Statement for diabetic
foot disorders stated that the rationale for using electrical stimulation in wound healing stems from the fact that
the body has an endogenous bioelectric system that enhances healing of bone fractures and soft tissue wounds.
According to ACFA clinical studies provide support for the use of electrical stimulation in wound care.
Auricular electroacupuncture, auricular electrostimulation or electrical auriculotherapy, is electrical stimulation of
auricular acupuncture points. Auricular therapy (AT) is most commonly based on the theory that the outer ear
has a somatotopic map and each part of the auricle corresponds to a specific part of the human body or organ.
By stimulating ear acupoints, AT is proposed to produce a positive impact by rebalancing the central nervous
system and treat a specific malfunctioning organ or systemic illness by applying a TENS unit to the correlating
part of the external ear. Electrical auriculotherapy has been suggested for use for smoking cessation, substance
abuse, obesity, adrenal disorders, acute and chronic pain control, headaches, arthritis, vertigo, high blood
pressure, inflammation, musculoskeletal disorders, relaxation, sciatica, stress, depression and swelling
(Schukro, et al., 2013; Electrotherapy Association, 2019).
U.S. Food and Drug Administration (FDA): Devices used for electro acupuncture are 510(k) approved by the
FDA as a Class II device. Examples of these devices are the ACULIFE/Model IDOC-Ol (Inno-Health Technology,
Co., Ltd. Taiwan, Republic of China), E-pulse model UH 900 (AMM Marketing LLC, Coral Springs FLA) and
Stivax System (Biegler Gmbh, Bonita Springs, FLA) which were approved as predicate devices for the PStim™
(NeuroScience Therapy Corp). The devices are approved “for use in the practice of acupuncture by qualified
practitioners of acupuncture as determined by the states” (FDA, 2016; FDA, Jun 2009; FDA, Dec, 2009).
Literature Review: There is insufficient evidence in the published peer-reviewed scientific literature to support
the effectiveness of auricular electroacupuncture. A limited number of randomized controlled trials have included
small patient populations (n=14–44) with a limited number of sessions (e.g., one) and short-term follow-ups (e.g.,
three months). Outcomes are conflicting and no significant differences for some outcome measures (e.g.,
postoperative laparoscopic pain; heart rate, blood pressure, overall quality of life) have been reported. Studies
were conducted to evaluate various conditions and indications including: hypertension, decrease the need for
anesthesia; treatment for cervical pain, postsurgical gynecological pain and rheumatoid arthritis; chronic kidney
disease, measure vagal activity in men; and for the treatment of depression (Kim, et al., 2016; Yeh, et al., 2015;
Hein, et al., 2013; Holzer, et al., 2011; Tsang, et al., 2011; La Marca, et al., 2010; Sator-Katzenschlager, et al.,
2003; Greif, et al., 2002).
Zhao et al. (2015) conducted a systematic review of randomized controlled trials (RCTs) to assess the safety
and efficacy of auricular therapy (AT) for the management of chronic pain. Subjects were age > 18 years with
any chronic pain syndrome (pain for > 3 months). Trials compared AT (auricular acupuncture, auricular
acupressure or auricular electro-stimulation, etc.) to one or more of the following: sham AT, waiting-list, standard
medical treatment or no treatment. Five studies included auricular electrostimulation for the treatment of low
back pain, rheumatoid arthritis, neck pain and miscellaneous chronic pain. Subgroup meta-analysis (four studies;
n=131) showed a significant improvement in pain (p=0.01) with auricular electrostimulation compared to the
control group interventions. Limitations of the studies included: small, heterogeneous patient populations,
heterogeneous acupoints and treatment regimens, short-term treatment sessions, and short-term follow up. Due
to the significant clinical heterogeneity and methodological flaws identified in the analyzed trials, there is
insufficient evidence to support auricular electrostimulation for the treatment of chronic pain management.
A systematic review including 43 randomized and nonrandomized controlled trials (Tan, et al., 2014) reported
that adverse events from the use of auricular therapy included: skin irritation; local discomfort and pain; and
minor infection. The events were transient, mild and tolerable. No serious adverse events had been reported.
Hayes (2012; reviewed 2014) conducted a search of the literature and reported on seven randomized controlled
trials evaluating the safety and efficacy of PStim. Four studies that investigated acute peri- and postoperative
pain reported conflicting results. The studies used PStim for pain from tooth extraction, laparoscopy,
intraoperative oocyte retrieval and tonsillectomy. Compared to sham, three studies reported no improvement in
pain or use of analgesic medication. Two additional studies reported an improvement with PStim for the
treatment of chronic cervical pain and low back pain. According to Hayes, the overall quality of the evidence was
low due to the limited number of studies and small patient populations. Only subjective outcome measures were
used and the majority of studies did not report functional outcomes or physical or psychosocial quality-of-life
measures. No severe, long-term adverse events have been reported. Additional well-designed studies are
needed to establish long-term effects and treatment regimens. The 2014 Hayes annual review found no new
Yeh et al. (2014) conducted a systematic review and meta-analysis of randomized controlled trials to assess the
efficacy of auricular therapy compared to sham therapy. A total of 22 randomized controlled trials met inclusion
criteria and 13 were used for meta-analysis. Auricular acupressure, auricular acupuncture and
electroacupuncture were evaluated. Included studies had to compare auriculotherapy to sham and/or standard
medical care with wait-list control and use a validated pain outcome measurement (e.g., Visual Analog Scale for
Pain [VAS Pain], Numeric Rating Scale for Pain [NRS Pain], or McGill Pain Questionnaire. In the two studies
using electroacupuncture stimulation (EAS), EAS was found to be nonsignificant for pain reduction compared to
sham or control group.
Sator-Katzenschlager et al. (2004) conducted a randomized controlled trial to compare the results of auricular
electroacupuncture (EA) (n=31) to conventional auricular acupuncture (CA) (n=30) for the treatment of chronic
low back pain. Common low back pain of muscular origin was noted in 36 subjects and 25 additional patients
had skeletal changes. Treatment was administered once a week for six weeks and needles were withdrawn 48
hours after insertion. Follow-up occurred at three months. During the study period and at three months follow-up,
patients completed the McGill questionnaire. The Visual Analog Scale was used to assess psychological wellbeing, activity level, quality of sleep, and pain intensity. Analgesic drug use was also documented. Compared to
the CA group, the EA group reported a significant improvement in pain relief (p<0.001), psychological well-being,
activity, sleep and analgesic consumption (p<0.001). More patients in the CA group returned to work (p=0.0032).
There were no reported adverse side effects. An author-noted limitation of the study included the lack of a
placebo-controlled group. Additional limitations include the small patient population and short-term follow-up.
Transcutaneous Electrical Modulation Pain Reprocessing (TEMPR)
Transcutaneous electrical modulation pain reprocessing (TEMPR), also called Scrambler therapy or Calmare®
pain therapy, delivers electrical stimulation via the nerve fibers to convey a message of normality to the central
nervous system (CNS) by a procedure defined as “scrambling” or “tricking” of information. The device is
proposed to send a very low current of electrical stimulation through the nerve fibers, which carries a “no pain”
signal to the brain that overrides the previous pain signal. Unlike conventional TENS, the procedure is
administered in an outpatient setting and is not intended for home use. The device is proposed to simultaneously
stimulate multiple pain areas in a patient. TEMPR has been proposed for the treatment of chemotherapy-induced
peripheral neuropathy, intractable cancer pain, failed back surgery syndrome, phantom limb pain, sciatica, postsurgical pain, neuropathic pain, brachial plexus pain, low back pain, neck pain, reflex sympathetic dystrophy and
post-herpetic neuralgia (PHN). Recommended treatment regimen for neuropathic pain is 10–12 daily sessions
(30–45 minute) and 10–12 treatments for oncologic patients based on the patient’s pain control needs
(Competitive Technologies, 2018; Marineo, et al., 2012).
U.S. Food and Drug Administration (FDA): The Scrambler Therapy MC-5A TENS device (Competitive
Technologies, Inc., Fairfield, CT) was approved by the FDA 510(k) process in 2009 and classified as a multichannel TENS that allows simultaneous treatment of a number of pain sites. It is indicated for “symptomatic relief
of chronic, intractable pain, post-surgical and post-traumatic acute pain”.
Literature Review: There is insufficient evidence in the published peer reviewed scientific literature to support
the efficacy of TEMPR. Studies comparing TEMPR to conventional treatment options and to sham therapy are
lacking. Available studies are primarily in the form of case series with small, heterogeneous patient populations
and short-term follow-ups investigating TEMPR for the treatment of various types of pain including cancer pain.
In some cases, pain relief was not maintained following therapy (Ricci, et al., 2019; Lee, et al., 2016; Notaro et
al., 2016; Coyne, et al., 2013; Ricci, et al., 2011; Smith, et al., 2010; Sabato, et al., 2005; Marineo, et al., 2003).
Hayes (2016; reviewed 2018) evaluated Calmare for the treatment of chronic nonmalignant pain. Seven studies
including two randomized controlled trials, 3 repeated-measure time series (observational studies), 1
pretest/posttest study and one retrospective review were included in the Brief. Outcomes were measured using
visual analog scale (VAS), numeric rating scale (NRS) (including the 11-point NRS-11), the Brief Pain Inventory
(BPI), and the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life
Questionnaire (QLQ) 20-point Chemotherapy-Induced Peripheral Neuropathy (CIPN-20) (EORTC QLQ CIPN-20)
and use of analgesics. Changes in pain were also measured by the use of analgesics. No adverse events were
reported. Although limited evidence suggested improvement in pain, “substantial uncertainty” remains due to the
lack of well-designed comparative studies. The overall quality of the evidence was rated “very low” and Hayes
concluded that there was insufficient evidence to assess the impact of Calmare on health outcomes or patient
management. The 2018 review reported one new case series and one pilot study with no change in Hayes’s
Hayes (2016; reviewed 2018) also evaluated the literature on Calmare for the management of chronic pain
related to cancer or cancer treatment. There was a paucity of “very-low-quality” evidence for cancer-related pain
in adult patients. The effect of Calmare when used as an adjunctive therapy was unclear, as were the long-term
effects. The criteria for electrode placement and impulse strength have not been defined. The 2018 review
identified one new prospective observational study (n=20) that did not change Hayes’ original assessment. There
is insufficient evidence to support the safety and effectiveness of Calmare for pain related to cancer and cancer
Marineo et al. (2012) conducted a randomized controlled trial to compare the effects of Scrambler therapy (n=26)
to guideline-based drug management (n=26) (control group) for the treatment of pain (i.e., postsurgical
neuropathic pain, postherpetic neuralgia or spinal canal stenosis). Scrambler therapy included one 45-minute
session a day for ten days at the maximally tolerated stimulus. The primary outcome was change in visual
analogue scale (VAS) pain scores at one month. Secondary outcomes included VAS pain scores at two and
three months, pain medication usage and allodynia. At the one-month, two-month and three-month follow-up
visits, there was a significant reduction in the mean VAS score for the treatment group compared to the control
group (p<0.0001, each). More relapses occurred in patients with polyradicular pain than monoradicular pain.
Relapses in the test group were significant (p<0.001) but not in the control group (p>0.05). No adverse effects
were observed. Compared to the control group, allodynia significantly reduced in the Scrambler group at one,
two and three months (p=0.0017, p=0.0094, p=0.0644, respectively). Scrambler therapy was also associated
with significant pain medication reduction and dosage variation was statistically significant (p<0.0001). Authornoted limitations included: lack of a sham comparator, the type of treatment provided to the control group, and
the small sample size. Other limitations are the short-term follow-up and heterogeneity of the patient population.
Electrical Stimulation In-Home Devices (Electrical Stimulators)
Neuromuscular Electrical Stimulation (NMES)
NMES is the application of electrical current through electrodes on the skin to targeted muscles to elicit muscle
contraction and relaxation. NMES is proposed to promote muscle restoration and to prevent or diminish muscle
atrophy and spasms and is an established treatment modality for disuse atrophy when the nerve supply to the
muscle is intact. NMES is typically used as a component of a comprehensive rehabilitation program. Protocols in
the literature recommend no more than two hours of NMES treatment within a 24-hour period and the treatment
plan is typically re-evaluated every 30 days. Compared to transcutaneous electrical neurostimulation (TENS),
NMES delivers a stronger current with a wider pulse width.
U.S. Food and Drug Administration (FDA): Neuromuscular electrical stimulators are 510(k) FDA approved as
Class II devices. An example of a NMES device is the EMS 7500 (Koalaty Products, Ind., Roswell, GA). The
device is approved for “(1) relaxing muscle spasms, (2) increasing local blood circulation, (3) immediate postsurgical stimulation of calf muscles to prevent venous thrombosis, (4) muscle re-education, (5) maintaining or
increasing range of motion, and (6) preventing or retarding disuse atrophy.”
Literature Review – Disuse Atrophy: Systematic reviews and randomized controlled trials support NMES for
the treatment of disuse atrophy and reported that NMES was as effective as, or more effective than, exercise
(Bax, 2005; Lieber, et al., 1996). NMES is a well-established treatment modality for disuse atrophy when the
nerve supply to the muscle is intact.
Literature Review – Other Indications: There is insufficient evidence to support the effectiveness of NMES in
the prevention and/or management of multiple conditions including: aerobic NMES for diabetes mellitus and
obesity; cancer; congestive heart failure; chronic obstructive pulmonary disease (COPD); deep vein thrombosis;
knee rehabilitation following injury or surgical intervention; muscular dystrophy; muscle wasting and weakness
associated with cancers; cerebral palsy; stroke; swallowing; toning, strengthening and firming of abdominal
muscles; osteoarthritis (e.g., of the knee); rheumatoid arthritis; fecal incontinence; low back pain; Bell’s palsy;
sensory stimulation for coma patients; motor disorders; and chronic ulcers. Overall, studies in the form of
randomized controlled trials and case series included small, heterogeneous patient populations and short-term
follow-ups. Some systematic reviews have reported that no improvement was seen with NMES, outcomes were
conflicting and/or in some cases, when improvement was noted, the effects did not last. Heterogeneity of
treatment regimens and outcome measures make it difficult to establish that NMES resulted in meaningful
clinical outcomes (e.g., decrease pain, functional improvement, improvement in quality of life and ability to carry
out activities of daily living) for these other conditions and indications.
Advanced Disease: Maddocks et al. (2013) conducted a Cochrane systematic review of randomized controlled
trials to investigate the effectiveness of NMES in improving muscle strength in adults with advanced disease.
Eleven studies evaluating NMES to no exercise or placebo NMES for the treatment of advanced COPD (8
studies; n=126), chronic heart failure (2 studies; n=76) or thoracic cancer (1 study; n=16) were included. The
primary outcome was quadriceps muscle strength assessed immediately following a program of NMES.
Secondary outcomes included: adherence to prescribed program, adverse events, muscle strength, endurance
and mass with maximal and submaximal exercise capacity, breathlessness and aspects of health-related quality
of life. NMES significantly improved quadriceps strength by a standardized mean difference of 0.9, equating to
approximately 25 Newton meters, a unit of torque. Mean differences across various walking tests, favored NMES
including 40 meters for the six-minute walk test, 69 meters for the incremental shuttle walk test and 160 meters
for the endurance shuttle walk test. No serious adverse events were reported. Although the use of NMES
showed improvement in leg muscle strength and ability to exercise, studies were limited by small patient
populations, short-term follow-ups, and heterogeneity of inclusion criteria, place of service (home vs. inpatient),
program characteristics and stimulation parameters. An update of this review in 2016 (Jones, et al.) included 18
studies (n=933). The overall conclusions remained the same. The quality of the evidence comparing NMES to a
control was low for quadriceps muscle strength, moderate for occurrence of adverse events, and very low-to-low
for all other secondary outcomes. Due to the limited data, the most beneficial type of NMES program for the
treatment of advanced disease could not be determined. Further research is needed to understand the role of
NMES as a component of, and in relation to, existing rehabilitation approaches for these individuals.
Chronic Obstructive Pulmonary Disease: A 2018 randomized controlled trial (n=73) reported that home-based
NMES as an add-on to pulmonary rehabilitation did not result in further improvements in subjects with severe to
very severe COPD. Inclusion criteria were the following: aged ≥ 18 years; forced expiratory volume in one
second < 60% predicted with a total lung capacity > 80% predicted; baseline modified Medical Research Council
dyspnea scale ≥ 1; and optimized medical therapy. Exclusion criteria included: body mass index (BMI) < 18 or > 35kg/m2; pregnancy or potential pregnancy; peripheral neuropathy; contraindication to cardiopulmonary
exercise testing (CPET); progressive cancer; cardiac pacemaker; and implanted cardiodefibrillator. Subjects
were randomized to pulmonary rehabilitation with and without NMES. There were within group significant
increases in the distance walked during the 6-minute walk test (6MWT) (p≤0.01), peak oxygen consumption
(p=0.02), maximal workload (p<0.01), modified Medical Research Council dyspnea scale (p<0.01) and Saint George’s Respiratory Questionnaire total score (p=0.01), but there were no significant differences in the outcomes between the groups (Bonnevie, et al., 2018). Hill et al. (2018) conducted a Cochrane review of sixteen randomized controlled trials (n=267) to determine the effects of NMES on subjects with chronic obstructive pulmonary disease (COPD). Seven studies investigated the effect of NMES versus usual care and nine assessed the effect of NMES plus conventional exercise training versus conventional exercise training alone. Six studies utilized sham stimulation in the control group. When applied in isolation, NMES produced an increase in peripheral muscle force and quadriceps endurance but the effect on thigh muscle size was unclear. There were increases in the six-minute walk distance (6MWD) and time to symptom limitation exercising at a submaximal intensity There was a reduction in the severity of leg fatigue on completion of an exercise test. The increase in peak rate of oxygen uptake was of borderline significance. For NMES with conventional exercise training, there was an uncertain effect on peripheral muscle force and there were insufficient data to perform a meta-analysis on the effect on quadriceps endurance or thigh muscle size. There was an increase in 6MWD in favor of NMES combined with conventional exercise training. There was no risk difference for mortality or minor adverse events in participants who received NMES vs. the comparator. The quality of evidence was graded as low or very low. Studies were limited by the risk of bias, imprecision of the estimates, small number of studies and inconsistency between the studies. There is insufficient evidence to establish the clinical benefit of NMES in the treatment of COPD. Dysphagia: Tan et al. (2013) conducted a systematic review and meta-analysis to compare the efficacy of NMES to traditional therapy (TT) in dysphagia rehabilitation. Three randomized controlled trials and four case series (n=291) met inclusion criteria. Outcomes were measured using the Functional Oral Intake Scale (FOIS), Swallow, Functional Scoring System (SFSS), American Speech-Language-Hearing Association National Outcome Measurement System (ASHA NOMS) Swallowing Level Scale, and M.D. Anderson Dysphagia Inventory (MDADI). Four studies compared NMES only to TT and three compared NMES with TT to TT alone. The Swallowing Function Scale of patients treated with NMES were significantly higher compared with patients treated with TT (p=0.02) but subgroup analysis according to etiology (I.e., stoke, cancer and Parkinson’s disease) showed no significant differences between NMES and TT in post-stroke dysphagia. Limitations of the studies included the inclusion of four nonrandomized controlled trials, poor study designs, and heterogeneity of patient population and outcome measures. Due to the limitations, these outcomes need to be validated in welldesigned randomized controlled trials with large patient populations and long-term follow-ups. Heart Failure: Arena et al. (2010) conducted a systematic review of the literature to evaluate the evidence supporting NMES and inspiratory muscle training (IMT) for the treatment of systolic heart failure. Thirteen NMES studies met inclusion criteria, ten were randomized controlled trials. Although the studies reported improvement in aerobic capacity, peak oxygen uptake and strength and endurance of muscle groups, the studies were limited by patient population (i.e., mostly males), diverse NMES training protocols, variation in the type of muscle contraction elicited (i.e., titanic vs. twitch), the use of different muscle groups and different comparators. The percent improvement in peak oxygen uptake was consistently greater with conventional therapy (i.e., bicycle/treadmill). Sillen et al. (2009) conducted a systematic review of randomized controlled trials to analyze the role of NMES in strength, exercise capacity, and disease-specific health status in patients with congestive heart failure (n=9 studies) and chronic obstructive pulmonary disease (n=5 studies) with disabling dyspnea, fatigue, and exercise intolerance. The limited number of studies, heterogeneous patient populations and variability in NMES methodology prohibited the use of meta-analysis. Although some of the studies reported significant improvements with NMES compared to no exercise or usual care, outcomes, including adverse events, were conflicting. Additional studies are indicated to provide sufficient evidence to establish the clinical utility of NMES in this patient population. Knee Indications: Martimbianco et al. (2017) conducted a Cochrane review of randomized controlled trials to evaluate the benefits and harms of NMES for the treatment of patellofemoral pain syndrome, generally referred to as patellofemoral pain (PFP). Eight randomized controlled trials (n=345) met inclusion criteria. Subjects were age 24–43 years, follow-ups ranged from one to six months, and there was a wide duration of symptoms. Comparators included exercise, different types of NMES, NMES with exercise vs. exercise alone, patellar taping and/or ice. Studies varied widely in the characteristics of the NMES regimen, its application and associated cointerventions. There is insufficient evidence to support beneficial clinical outcomes from NMES when used for the treatment of PFP. There was a high risk of bias in the studies, conflicting outcomes, and “very low” quality of evidence. Volpato et al. (2016) conducted a systematic review of randomized controlled trials to evaluate the effectiveness of NMES on adults who underwent rehabilitation following postoperative total knee arthroplasty. Four studies (n=376) met inclusion criteria. Primary outcome included function or disability evaluation. There was no statistically significant difference in knee function, pain and range of motion during the 12 month follow-up. Neuromuscular electrical stimulation was less effective than traditional rehabilitation in function, muscular strength and range of motion. Although postoperative treatment with NMES showed improvement in the femoral quadriceps function, due to the low quality evidence the clinical effectiveness of this intervention is unknown. No evidence indicated if NMES with physiotherapy provided benefits regarding the quality of life. There is insufficient evidence to support neuromuscular stimulation for quadriceps strengthening with physical therapy before or after total knee replacement. De Oliveira Melo et al. (2013) conducted a systematic review to identify the evidence for NMES for strengthening quadriceps muscles in elderly patients with knee osteoarthritis (OA). Inclusion criteria were randomized controlled trials comparing pre and post-intervention, elderly patients with clinical diagnosis of knee OA and outcome measurements of quadriceps muscle strength measured preferentially with an isokinetic dynamometer. Six randomized controlled trials (n=35–200) met inclusion criteria. Four studies included ≤ 50 patients. Study designs and outcome measures were heterogeneous and comparators varied. NMES parameters were poorly reported. The trials scored extremely low on the allocation concealment and blinding items. In most of the trials, the randomization methods were not described. Due to the poor methodology of the studies and poor description of the strength measurement methods, no or insufficient evidence was found to support NMES alone or combined with other modalities for the treatment of elderly patients with OA. Due to the study limitations, no meta-analysis was performed. Giggins et al. (2012) conducted a systematic review and meta-analysis to assess the effectiveness of NMES for the treatment of knee osteoarthritis. Nine randomized controlled trials (n=395) and one controlled trial (n=14) were included. Outcome measures included self-reported disease-specific questionnaires and pain scales, strength measurements, knee range of motion, knee and thigh circumference and functional assessments. Two studies were considered of strong quality, four moderate and four of weak quality. Overall, there was inconsistent low level evidence that NMES significantly reduced pain and increased strength and function. Pooled analyses of six studies showed that NMES improved levels of self-reported pain and function, but not objective measures of function. The authors noted that the results should be interpreted with caution due to the heterogeneity of studies. Due to the conflicting data, definitive conclusions regarding the effectiveness of NMES for the treatment of knee osteoarthritis could not be made. Kim et al. (2010) conducted a systematic review of randomized controlled trials (n=8) to assess the effectiveness of NMES on “quadriceps strength, functional performance, and self-reported function after anterior cruciate ligament reconstruction.” Control interventions included: therapeutic exercises, EMG biofeedback, TENS plus exercises, and weight-bearing exercises. Quadriceps strength outcomes varied with some studies favoring NMES while others reported equivocal results or favored control interventions. One study each reported functional testing (n=20) and patient self-reported outcomes (n=43). Although some studies reported improvement following NMES, this analysis was limited by the use of various NMES regimens (e.g., treatment duration ranged from three to 11 weeks, number of sessions ranged from 12–105) and overall, only one followup visit occurred immediately following completion of treatment sessions. There is insufficient evidence to support clinical meaningful benefit of NMES on functional performance. In a systematic review of randomized controlled trials, Monaghan et al. (2010) assessed the effectiveness of NMES in strengthening quadriceps before and after total knee replacement. Two studies met inclusion criteria. NMES plus exercise resulted in better quadriceps muscle activation compared to exercise alone (n=39), but was not maintained at the 12-week follow-up. No significant differences were reported in either study for maximum voluntary isometric torque or endurance between the NMES group and the control group. In a 2008 systematic review of anterior cruciate ligament reconstruction (ACL) rehabilitation, Wright et al. reported that 14 randomized controlled trials had evaluated postoperative NMES following ACL reconstruction. Because of the variety of parameters in the studies; poor study quality; heterogeneous patient populations; and the lack of randomization, blinding and independent observers, the authors noted that it was difficult to make generalized conclusions regarding NMES, and it did not appear to be a requirement for successful ACL reconstruction rehabilitation. Stroke: Stein et al. (2015) conducted a systematic review (n=29 studies; 940 subjects) and meta-analysis (n=14 studies; 383 subjects) of randomized controlled trials to evaluate the effect of NMES on spastic muscles after stroke. The primary outcome was spasticity, assessed by the Modified Ashworth Scale. The secondary outcome was range of motion (n=13 studies), assessed by a goniometer. Outcomes were conflicting. Some studies reported an improvement in spasticity (n=12 studies) and range of motion (n=13 studies) with NMES when used as an adjunctive therapy and some studies did not. Based on sensitivity analysis, no effects on spasticity and range of motion were seen on wrists and no effect on spasticity of elbows. The degree of spasticity and the criteria for spasticity assessment varied. Most studies showed evidence of bias. Other study limitations included: heterogeneity of outcome measures; time of treatment following stroke (1.5 months to more than 12 months); various degrees of chronic tissue changes; heterogeneity of conventional therapies used (e.g., active leg cycling, occupational therapy, stretching, Botulinum Toxin A), missing data; and heterogeneity of stimulation frequency and pulse duration. Large scale and high-quality randomized controlled trials are needed to establish the true efficacy NMES in this patient population. In a randomized controlled trial (n=60), Hsu et al. (2010) compared high-NMES and low-NMES to a control group (standard rehabilitation) for the treatment of upper-extremity function in acute stroke patients. The low NMES group received 30 minutes of stimulation per day and the high-NMES group received 60 minutes per day, five times per week, for four weeks. All patients received standard rehabilitation. Compared to the control group, the NMES groups showed significant improvement in the Fugl-Meyer Motor Assessment (p=0.003) and Action Research Arm Test scales (p=0.016) at week four and week 12. There were no significant differences between low- and high-NMES stimulation. No significant differences between the groups were reported on the motor activity log. Limitations of the study include the small patient population, short-term follow-up, and 12 patients lost to follow-up. Transcutaneous Electrical Nerve Stimulation (TENS) A TENS device consists of an electronic stimulus generator that transmits pulses of various configurations through electrodes attached to the skin to stimulate the peripheral nerves for the purpose of pain management. Conventional TENS or high frequency TENS delivers 40–150 hertz (Hz) compared to acupuncture-like TENS that delivers a low frequency at 1–10 Hz. Pulsed TENS uses low-intensity firing in high-frequency bursts at 100 HZ. TENS has been used for a number of applications, including postoperative pain; acute and chronic pain, obstetrical pain, and pain associated with medical procedures. U.S. Food and Drug Administration (FDA): TENS are approved by the FDA 510(k) process as a Class II device for the relief and management of chronic intractable pain. Examples of these devices include the Empi Active Transcutaneous Nerve Stimulator (Empi, Inc., Clear Lake, SD), the StimPad™ TENS System (AEMED, Inc. West Palm Beach, FLA), the ReBuilder® (Micromed, Inc., Essex Junction, VT) and the BiowaveHOME neuromodulation pain therapy device (Biowave Corporation, Norwalk CT). In 2014, FDA approved the Cefaly Supraorbital Transcutaneous Neurostimulator (Cefaly-Technology, Herstal, Belgium) through the 510(k) de novo premarket review pathway, a regulatory pathway for generally low- to moderate-risk medical devices that are not substantially equivalent to an already legally marketed device. FDA classified the Cefaly as a Class II device indicated for the prophylactic treatment of episodic migraine in patients 18 years of age or older. FDA noted that this is the first TENS device approved for use prior to the onset of pain. In 2017 the Cefaly Acute and Cefaly Dual were FDA approved as 510(k) Class II TENS to treat headaches. The Cefaly Acute is “indicated for the acute treatment of migraine with or without aura in patients 18 years of age or older”. The Cefaly Dual is indicated for 1) the acute treatment of migraine with or without aura in patients 18 years of age or older and 2) the prophylactic treatment of episodic migraine in patients 18 years of age or older (FDA, 2017). The device is worn on the forehead for 20 minutes daily. It is proposed to externally stimulate the supraorbital and supratrochlear branches of the trigeminal nerve to normalize dysregulated pain pathways. These devices are also referred to as transcutaneous supraorbital neurostimulators (tSNS) or external trigeminal nerve stimulator (eTNS) (Lauritsen, et al., 2018; American Migraine Foundation, 2017). Literature Review – Acute Postoperative Pain The evidence in the peer-reviewed literature supports TENS for the treatment of pain in the acute post-operative period (i.e., within 30 days of surgery). Systematic reviews, meta-analysis and randomized controlled trials reported a reduction in pain and analgesic use in the treatment of acute post-operative pain and in some cases, shorter recovery times (Li and Song, 2017; Zhu, et al., 2017; Sbruzzi, et al., 2012; Freynet and Falcoz, 2010; Bjordal, et al., 2003). Literature Review – Other Indications: The evidence in the published peer-reviewed scientific literature has not established the effectiveness of TENS for the treatment of any other indications including, but not limited to: chronic low back pain; cervical pain; acute pain; acute and chronic headaches; migraines; abdominal pain; asthma; chemotherapy-induced pain; chronic leg ulcers; colonoscopy; drug withdrawal (e.g., opiate addiction); dysmenorrhea; fibromyalgia; fracture healing; hypertension; interstitial cystitis; knee osteoarthritis; mandibular disorders (e.g., neuromuscular orthodontics; temporomandibular joint [TMJ]); motion sickness; nausea and vomiting of pregnancy; postoperative nausea and vomiting; low back pain of pregnancy; pain associated with childbirth (i.e., labor); pelvic pain; post-traumatic acute pain; walking pain associated with peripheral artery disease; chronic anal fissure; rotator cuff tendinitis; stroke rehabilitation; suspected placental insufficiency; tinnitus; fecal incontinence; urinary incontinence; vestibulodynia; and unstable angina. Overall, systematic reviews, randomized controlled trials and case series have reported that there was no improvement with TENS for these indications or conclusions could not be made due to the poor methodology of the studies. Study limitations included small heterogeneous patient populations with short-term follow-ups, insufficient data or conflicting data, and heterogeneity of the application of TENS (e.g., physician applied vs. patient applied, location of electrodes). Evidence supporting TENS for these indications is lacking nor is TENS an established treatment modality. The clinical utility of TENS has not been established for all other indications. Acute Pain: Johnson et al. (2015a) conducted a systematic review of randomized controlled trials to evaluate TENS as the sole treatment for acute pain (less than 12 weeks duration). Studies that met inclusion criteria compared TENS to placebo, no treatment, pharmacological interventions or non-pharmacological interventions. Nineteen studies (n=1346) met inclusion criteria. The types of acute pain included: procedural pain, (e.g., cervical laser treatment, venipuncture, screening flexible sigmoidoscopy) and non-procedural pain (e.g., postpartum uterine contractions, rib fractures). Data was pooled for pain intensity in studies comparing TENS to placebo, (n=6 trials), for subjects achieving ≥ 50% pain reduction (n=4 trials), and pain intensity from noncomparative studies (n=5 trials). It was not possible to pool other data. There was some tentative evidence that TENS reduced pain intensity over placebo when TENS was administered alone. However, the reduction in pain was inconsistent across studies and there was insufficient number of patients to make a firm conclusion. Limitations of the studies included: high risk of bias, heterogeneity of patient populations, inadequate sample sizes in treatment arms and unsuccessful blinding of treatment interventions. The incomplete reporting of treatment made replication of many trials impossible. Adverse events included mild erythema and itching beneath the TENS pads and dislike of the sensations produced by the devices. The evidence does not support TENS for the treatment of acute pain. Walsh et al. (2009) assessed the analgesic effectiveness of TENS in acute pain for adults (n=919) in a systematic review of 12 randomized controlled trials. The types of acute pain included procedural pain (e.g. cervical laser treatment, venipuncture, screening flexible sigmoidoscopy) and nonprocedural pain (e.g. postpartum uterine contractions, rib fractures). The authors were unable to make any definitive conclusions due to the insufficient extractable data. Fibromyalgia: Johnson et al. (2017) conducted a Cochrane review of randomized or quasi-randomized controlled (RCT) trials to assess the analgesic efficacy and adverse events of TENS for the treatment of fibromyalgia in adults. Primary outcomes were participant-reported pain relief from baseline ≥ 30% or ≥ 50% and Patient Global Impression of Change (PGIC). Eight RCTs (n=315) met inclusion criteria. Two studies compared TENS with placebo TENS (n=82). One study compared TENS with no treatment (n=43) and four studies compared TENS with other treatments including pharmacotherapy (n=74), electroacupuncture (n= 44), superficial warmth (n=32 participants) and hydrotherapy (n=10). Two studies compared TENS plus exercise with exercise alone (n=98). One study reported ≥ 30% pain relief. No study measured participant-reported pain relief of 50% or greater or PGIC. Statistical pooling of outcomes was not possible because of the insufficient data and heterogeneous outcomes. No serious adverse events were reported. Due to the small patient populations, heterogeneity of study designs and low grade of evidence, the clinical benefit of TENS for the treatment of fibromyalgia could not be determined. Back Pain: Hayes (2018) conducted a technology assessment to evaluate the efficacy and safety of different forms of transcutaneous electrical nerve stimulation (TENS) compared with each other, with sham TENS, and with other minimally invasive nerve stimulation interventions for the treatment of adults with chronic low back pain (CLBP). Nine randomized controlled trials (RCTs) met the inclusion criteria. Interventions included: acupuncture-like TENS (AL-TENS), high-frequency TENS (HF-TENS), and low-frequency TENS (LF-TENS). Comparators were diadynamic current (DDC); high voltage electrical stimulation (HVES); interferential current (IFC); percutaneous electrical nerve stimulation (PENS); percutaneous neuromodulation therapy (PNT); and other TENS methods including sham. Outcome measures were pain, functional status, quality of life, sleep quality, physician rating of patient impairment, nonsteroidal anti-inflammatory (NSAID) and other analgesic use. Hayes described the body of evidence as moderate in size and low in overall quality. The available evidence did not support the use of TENS to relieve pain and/or improve pain. Three RCTs found that TENS was no more effective than sham and a fourth study reported mixed results depending on the outcome measure. Two RCTs found TENS to be inferior compared with PENS. One RCT found TENS to be inferior compared with PNT in some outcomes and no different in others. Another RCT found no significant differences between TENS and IFC, a second RCT found IFC to be superior; and a third study found TENS to be similar to HVES and superior to DDC. Different types of TENS were similar to each other in four studies. No serious complications were reported. Minor skin irritation at the electrode sites was the only TENS-related complication reported in the evaluated studies. Hayes concluded that there is no proven benefit of TENS in the treatment of chronic low back pain. Wu et al. (2018) conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) that compared the effectiveness of TENS to sham and other nerve stimulation therapies (NSTs) for the treatment of chronic back pain (CBP). Chronic pain was defined as pain lasting > 12 weeks. Twelve studies (n=700) met the
inclusion criteria. RCTs were included if patients were age ≥ 18 years, treated for CBP, and the intervention
compared TENS to sham, placebo, medication only or other types of nerve stimulation therapies (NSTs). Other
NSTs included electroacupuncture (EA) (one study), percutaneous electrical nerve stimulation (PENS) and
percutaneous neuromodulation therapy (PNT). Studies were excluded if they did not provide numerical data
regarding the degree of pain or disability. Letters, comments, editorials, and case reports were also excluded.
The primary outcome was the difference in the mean change in pain from baseline to after the intervention. The
secondary outcome was the difference between groups in improvement of functional disability. Nine TENs vs.
sham/placebo studies reported pain scores before and after the intervention and were included in the metaanalysis. Patient populations ranged from 13–167 and follow-ups occurred at one week to three months. There
was no significant difference in the improvement of functional disability in TENS vs. controls. For patients with a
follow-up period of < 6 weeks, TENS was significantly more effective than sham in improving functional disability
(p<0.001). No significant difference in functional disability between the two groups was seen with a follow-up ≥ 6
weeks (p=0.707). Five studies (n=19–102) compared TENS to other NSTs. In patients with a follow-up period of
< 6 weeks, other types of NSTs were significantly more effective than TENS in providing pain relief (p=0.021).
However, no significant difference in the pain relief was seen in patients with follow-up ≥ 6 weeks (p=0.326).
Only two studies provided disability data comparing scores before and after treatment and follow-ups were < 6
weeks. There was no significant difference in improvement between the two groups. Limitations of the analysis
included the limited number of studies that met inclusion criteria, short-term follow-ups, and the small
heterogeneous patient populations which limited the general applicability of the results. The results suggested
that TENS does not improve symptoms of lower back pain, but may offer short-term improvement of functional
disability. Additional RCTs comparing the efficacy of TENS and other established treatment modalities are
needed to establish the clinical value of TENS for the treatment of this subpopulation.
Resende et al. (2018) conducted a systematic review and meta-analysis to evaluate the safety and effectiveness
of transcutaneous electrical nerve stimulation (TENS) or interferential current (IFC) for the treatment of chronic
low back pain (CLBP) (n=575) and/or chronic neck pain (CNP) (n=80). Nine randomized controlled trials met
inclusion criteria and seven TENS studies with complete data sets were used for meta-analysis (n=655). TENS
was compared with sham TENS or standard of care. Studies were included if patients were age ≥ 18 years and
had a diagnosis of non-specific CLBP and/or CNP. CLBP was defined as low back pain that had persisted for ≥ 3
months without radicular signs and was not caused by a primary conditions (e.g., cancer, multiple sclerosis,
rheumatoid arthritis). CNP was defined as nonradicular pain located in the anatomical region of the neck that had
persisted for ≥ 3 months and no specific cause had been identified (e.g., infection, neoplasms, metastasis,
osteoporosis, rheumatoid arthritis, fractures or inflammatory processes). Studies were excluded if they reported
subjects with acute or subacute pain or investigated subjects with medical diagnosis, signs or symptoms of
radiculopathy, previous back surgery, pain conditions other than CLBP or CNP, mixed pain conditions and/or
used a form of electrical stimulation other than TENS or IFC. The primary outcome measures included: pain
intensity, visual analogue scale (VAS) and back function. Secondary outcomes were Short-Form Health Survey
(SF-36), patient satisfaction survey and adverse events. Follow-ups ranged from immediately after to three
months after treatment. Typically, treatment duration lasted 2–5 weeks, was performed 2–5 days per week, for
15–60 minutes. Only one trial evaluated subjects with chronic neck pain (n=80) and one used TENS and IFC.
Outcomes were conflicting. Four studies reported TENS was more effective than placebo/control for reducing
pain intensity and four reported no significant difference in pain intensity between the groups. CLBP metaanalysis (n=148) showed that TENS was significantly better in reducing pain than placebo/control (p<0.02).
TENS intervention was better than placebo/control during therapy (p=0.02), but not immediately after therapy
(p=0.08) or 1–3 months following therapy (p=0.99). Self- reported outcomes showed that TENS was no better
than placebo for improving back function (p=0.68). Limitations of the analysis includes the small number of
studies with small patient populations, short-term treatment and follow-ups, and heterogeneity of treatment
regimens, stimulation parameters and electrode placement. The authors noted that this systematic review
provided inconclusive evidence of TENS benefits in the treatment of chronic low back pain.
Jaurequi et al. (2016) conducted a systematic review and meta-analysis of the efficacy of TENS for the treatment
of chronic, musculoskeletal low back pain. Thirteen studies, which included randomized controlled trials, cohort
studies, and randomized crossover studies (n=267), met inclusion criteria. Follow-ups ranged from 2–24 weeks
with a mean follow-up of seven week. The duration of treatment ranged from 2–24 weeks (mean 6 weeks). The
overall standardized mean difference in pain from pre- to post-treatment with TENS showed a significant
improvement of TENS on pain reduction (p<0.001). When subdivided into treatment duration, patients that were
treated for less than five weeks (n=8 studies) had significant effects on pain, while those treated for more than
five weeks did not. The heterogeneity among studies was substantially significant (p<0.0001) among the TENS
groups. Limitations of the studies included: small patient populations; variations in treatment times, TENS
frequency and length of follow-up; and conflicting outcomes. The authors noted that despite the positive results,
large multi-center prospective randomized trials are needed to develop the appropriate treatment protocols for
this patient population.
The Centers for Medicare and Medicaid (2012) conducted a systematic review of the literature to evaluate TENS
for the treatment of chronic low back pain. Inclusion criteria included adults with chronic, persistent low back pain
(with or without leg pain) for three months or more and used TENS for at least four weeks. Included clinical trials
had a patient population of ten or more; well-defined comparators; and used all models, frequencies, and wave
patterns of TENS. Studies that examined chronic low back pain in patients with pain related to malignancy,
neurodegenerative diseases (e.g. multiple sclerosis) and well-defined rheumatic disorders (except for
osteoarthritis) were excluded. Seven systematic reviews and five randomized controlled trials met the inclusion
criteria. Relevant clinical practice guidelines were also considered. Following a review of the data, Medicare
concluded that TENS did not produce a clinically meaningful reduction in pain, a clinically meaningful
improvement in function or a clinically meaningful improvement in any other health outcomes. When compared
to TENS, sham units provided equivalent analgesia. The authors also noted that the potential for significant bias
in the studies included in this analysis limited their “confidence in the reported results of this body of literature”.
Buchmuller et al. (2012) conducted a 21-center, randomized controlled trial to evaluate the efficacy of TENS
(n=117) compared to sham (n=119) in improving functional disability in patients with chronic low back pain
(LBP), with or without radicular pain. Patients received treatment in four, one-hour daily sessions for three
months. The primary outcome measure was improvement of functional status at six weeks based on the
Roland–Morris Disability Questionnaire. Secondary outcome measures included functional status at three
months, pain relief by weekly visual analogue scale (VAS) assessments, quality of life, use of analgesic and antiinflammatory medication, satisfaction with the overall treatment strategy and compliance. Treatment was selfadministered and recorded stimulation frequency and duration were checked at each study visit to verify
compliance. Follow-ups occurred at 15 days, six weeks and three months. An improvement of at least 50% in
lumbar pain between the first and last assessments was significantly greater in the TENS group (p=0.0003). The
effect on pain intensity was particularly marked in the subgroup of patients with radicular pain. There were no
significant differences between the groups in functional status at six weeks (p=0.351) or three months (p=0.816)
or in any of the other outcome measures. Skin irritation was reported in 11 TENS patients and three sham
patients. The authors noted that “the overall results of this study do not support the use of TENS in the treatment
of patients with chronic LBP”. Limitations of the study include the short-term follow-up and heterogeneity of the
Khadilkar et al. (2008) conducted a systematic review to determine if TENS was more effective than placebo for
the management of chronic low back pain. Four “high-quality” randomized controlled trials (n=585) met inclusion
criteria. Due to conflicting evidence, the authors were unable to determine if TENS was beneficial in reducing
back pain intensity. Two trials involving 410 patients reported that TENS did not improve back-specific functional
status, the level of disability from the pain, the use of medical services or work status. There were no significant
differences in outcomes when conventional TENS was compared to acupuncture-like TENS.
Cancer Pain: Hurlow et al. (2012) conducted an update review of the 2009 review by Robb et al. One new study
met inclusion criteria (n=24). There were significant differences in participants, treatments, procedures and
symptom measurement tools used in the studies. The clinical utility of TENS for the treatment of cancer pain has
not been established. Robb et al. (2009) conducted a systematic review of the literature to evaluate TENS for the
treatment of cancer-related pain. Two randomized controlled trials (n=64) met inclusion criteria. Meta-analysis
was not conducted due to the disparities between patient population, mode of TENS, treatment duration, and
outcome measures prevented meta-analysis. There is insufficient evidence to support TENS for the treatment of
Chronic Pain: Gibson et al. (2019) conducted a review of all Cochrane Reviews on the effectiveness of TENS
for the treatment of chronic pain of any origin (e.g., rheumatoid arthritis, phantom stump pain, fibromyalgia,
osteoarthritis). Studies evaluating headaches and migraines were excluded. All Reviews (n=9) of randomized
controlled trials (RCTs) assessing the effectiveness of TENS versus sham; TENS versus usual care or no
treatment/waiting list; TENS plus active intervention versus active intervention alone; comparisons between
different types of TENS; or TENS delivered using different stimulation parameters were included. Primary
outcomes included pain intensity and adverse effects. Secondary outcomes included: disability, health-related
quality of life, analgesic medication use and participant global impression of change. One review including five
studies (n=207) reported a beneficial effect of TENS versus sham therapy at reducing pain intensity on a 0–10
scale (p<0.001). However, due to the significant methodological limitations the quality of the evidence was
considered very low. Pooled analysis from a second study comparing TENS to sham and TENS to no
intervention also reported a significant improvement with TENS. This analysis was also consider very low quality
evidence due to significant methodological limitations and large between-trial heterogeneity. Due to the
methodological limitations and lack of useable data no meaningful conclusions could be made on the
nature/incidence of adverse effects or the remaining secondary outcomes. Based on the poor quality of the
evidence, including small patient populations, a determination on the benefits and harms of TENS for the
treatment of chronic pain and its effect on disability, health-related quality of life, use of pain relieving
medications, or global impression of change could not be made.
Nnoaham et al. (2008) conducted a Cochrane systematic review to assess the effectiveness of TENS for the
treatment of chronic pain, present for three or more months. A total of 25 randomized controlled trials (n=1281)
met inclusion criteria. Included studies compared active TENS to sham TENS controls; active TENS to ’no
treatment’ controls; or active TENS to active TENS controls (e.g. High Frequency TENS versus Low Frequency
TENS). Due to the poor methodology of the studies, meta-analysis was not possible. Thirteen of 22 inactive
control studies, reported a positive analgesic outcome in favor of active TENS treatments. For multiple dose
treatment comparison studies, eight of 15 studies reported favorable outcomes for active TENS treatments and
seven of nine active controlled studies found no difference in analgesic efficacy between high frequency and low
frequency TENS. The authors concluded that “published literature on the subject lacks the methodological rigor
or robust reporting needed to make confident assessments of the role of TENS in chronic pain management.
Colonoscopy: Amer-Cuenca et al. (2011) conducted a randomized controlled trial (n=90) to evaluate the
effectiveness of TENS in controlling pain in unsedated patients undergoing screening colonoscopy. Patients
were randomized to one of three groups: control group (n=30), active TENS (n=30), or placebo TENS (n=30).
The control group received hospital standard protocol for unsedated colonoscopies without any kind of sedation
or analgesia. Pain was assessed five minutes into the procedure and at the end of the procedure using a visual
analogue scale (VAS) and a five-point Likert scale. The TENS group reported a ≥ 50% reduction in the VAS
scores compared to the placebo and control group (p<0.001). There was also a significant reduction on the Likert
scale scores in the TENS group compared to the placebo and control groups (p=0.009). There were no
significant differences between the groups in bloating sensation during the procedure and the duration of the
procedure. Greater than 50% pain relief was achieved by 17 TENS patients, three placebo patients and six
control patients (p<0.001). Author-noted limitations of the study included: the active TENS group’s experience of
pain might have been affected by the potential distraction of continuously adapting stimulus intensity and the use
of VAS as a measurement of pain. Another limitation is the small patient population.
Dementia: Cameron et al. (2003; updated 2005) conducted a systematic review on TENS for the treatment of
dementia. Nine randomized controlled trials met inclusion criteria, and three were included in meta-analysis. A
statistically significant improvement was reported immediately following therapy in: delayed recall of 8 words and
motivation in one trial, each and face recognition in two trials and motivation in one trial. However, the authors
concluded that there was insufficient data for definitive conclusions to be drawn.
Diabetic Neuropathy: Jin et al. (2010) conducted a systematic review to evaluate the effectiveness of TENS on
diabetic peripheral neuropathy. Three randomized controlled trials (n=78) met inclusion criteria. TENS was
reported more effective than placebo in the reduction of mean pain score at four and six weeks follow-up but not
at 12 weeks. Pieber et al. (2010) conducted a systematic review of the literature to evaluate electrotherapy,
including TENS, for the treatment of peripheral neuropathy in patients with diabetes. Three randomized
controlled trials (n=76) and one retrospective review (n=54) evaluating TENS met inclusion criteria. The studies
included short-term follow-ups and conflicting results. One study reported significant improvement in pain and
another study reporting recurrence of pain after cessation of TENS. Due to the small patient populations, shortterm treatment duration, short-term follow-up and poor study methodology, large multi-center randomized
controlled trials are needed to further evaluate the long-term effect of TENS on diabetic neuropathy.
Dysmenorrhea: In a systematic review of seven randomized controlled trials (n=164), Proctor et al. (2009)
evaluated the effectiveness of low-frequency TENS (acupuncture-like TENS, 1–4 hertz [Hz]) and high-frequency
TENS (conventional TENS, 50–120 Hz) (n=5) for the treatment of primary dysmenorrhea. Studies compared
TENS to placebo, no treatment or medical treatment. Overall, high-frequency TENS was reported more effective
than placebo TENS for relief of pain. There was no difference in pain relief with low-frequency TENS compared
to placebo. There were conflicting results regarding whether high-frequency TENS was more effective than lowfrequency TENS. Due to the small patient populations, various methods of the application of TENS, and the lack of precision in the comparisons, clear recommendations for clinical applications could not be made.
Fecal Incontinence: Edenfield et al. (2015) conducted a systematic review of the literature to assess the safety
and effectiveness of cutaneous (TENS) and percutaneous posterior tibial nerve stimulation (PTNS) for the
treatment of fecal incontinence. Regarding the use of cutaneous TENS, three randomized controlled trials and
five case series met inclusion criteria. Outcomes included bowel diary information and generally reported
improvement in fecal incontinence and bowel movement deferment time. Quality of life outcomes (coping,
embarrassment, depression, general health) were conflicting. Some patients in sham groups reported
improvement in symptoms. No serious adverse events were reported. Overall study quality was “poor” based on
the study design. Some of the trials were pilot studies. Additional limitations of the studies included small patient
populations (n=10-144) and short-term follow-ups (4-12 weeks) with maintenance sessions ranging from 1–40
months. Outcomes and treatment techniques were inconsistent. Well-designed randomized controlled trials with
large patient populations and long-term follow-up are needed to compare the effectiveness of TENS to
Horrocks et al. (2014) conducted a systematic review to evaluate the safety and efficacy of posterior tibial nerve
stimulation for the treatment of fecal incontinence. Five studies investigating cutaneous PTNS met inclusion
criteria. Primary outcome measure was an improvement of at least 50% in the number of incontinent episodes.
Secondary outcomes included reduction in weekly incontinent episodes, cure rates, improvement in incontinence
scores and improvement in quality-of-life measurements. The proportion of patients who reported a reduction in
fecal incontinence episode of at least 50% ranged from 0%–45% compared to baseline. In a randomized
controlled trial, no significant difference was seen in TENS vs. sham and no patient had a 50% or greater
reduction in weekly incontinence episodes. Overall, TENS stimulation of the posterior tibial nerve did not improve
Labor: Bedwell et al. (2011) conducted a systematic review of randomized controlled trials comparing TENS to
routine care or placebo devices for labor pain. Fourteen studies (n=1256) met inclusion criteria. TENS were
applied to the back (n=11 studies), acupuncture points (n=2 studies) and in one study to the cranium. Primary
outcome measures were pain intensity and patient satisfaction with pain relief. Secondary outcome measures
included: duration of labor, cervical dilation on admission to hospital, augmentation of labor, other pain relief,
assisted birth or caesarean section, side effects, and sense of control in labor. Outcomes for neonates included
Apgar score (<7 at five minutes), cord pH (<7.1) and adverse events. Patients receiving TENS to acupuncture
points were less likely to report severe pain. There were no significant differences in use of epidural analgesia or
other types of analgesia between the groups, pain ratings and patient satisfaction. None of the studies reported
information on Apgar scores or cord pH or women’s sense of control in labor. There was no information that
TENS affected any other outcomes on the mother or the baby. No adverse events were reported. The authors
concluded that there was limited evidence that TENS reduced pain during labor but the “evidence is neither
strong nor consistent”. The use of TENS at home in early labor has not been evaluated. Author-noted limitations
of the studies included: small patient populations, unbalanced study groups, heterogeneity of outcome
measures, various type of TENS devices were used, TENS was offered alone or as an adjuvant therapy making
it difficult to assess the true effect of TENS in some studies, and pain was measured in so many different ways it
was not possible to pool results.
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