Description:
Neuromuscular electrical stimulation (NMES) involves the use of a device which transmits an electrical impulse to the skin over muscle groups by way of electrodes. This technology is proposed to stimulate the muscle while the individual is in a resting state to prevent or treat muscle atrophy and is indicated for individuals with intact nerve supply to the muscle. This technology differs from Functional Neuromuscular Electrical Stimulation (addressed in a separate policy) which is proposed for use in individuals who are neurologically impaired (e.g., stroke, spinal cord injury).

When subjected to insufficient use, muscles atrophy, resulting in a loss of strength and mass. Muscle atrophy may occur when the limbs are immobilized after injury or surgery (e.g., casting or splinting of limb, contracture due to scarring of soft tissue as in burn lesions, hip replacement surgery). The NMES device is proposed to stimulate the motor nerves with electrical currents, generating muscle contractions to reverse muscle atrophy. The intensity and frequency of stimulation can vary based on the level of muscular function and treatment response. Examples of devices that have received 510(k) marketing clearance for the treatment of muscle atrophy include RS Medical’s RS-2m™ 2-channel and RS-4m^® 4-channel muscle stimulator.

Neuromuscular electrical stimulation has also been studied in the treatment of spastic muscles related to cerebral palsy and spina bifida. For this indication, the stimulation is not intended to cause muscle contraction. Although the mechanism of action is not understood, it is thought that low-intensity stimulation (sub-threshold level) may increase muscle strength and joint mobility, leading to improved voluntary motor function. This technique is referred to threshold electrical stimulation.

H-wave stimulation is a distinct form of electrical stimulation that has been investigated primarily for treatment of pain from a variety of etiologies including diabetic neuropathy, muscle sprains, temporomandibular joint dysfunction (TMJ), and reflex sympathetic dystrophy (RSD). H-wave stimulation has also been used to accelerate wound healing such as diabetic ulcers and to improve range of motion and function to prevent muscle atrophy after orthopedic surgery. This technology produces a direct, localized effect on the conduction of underlying peripheral nerves and may be used in the home setting. It differs from transcutaneous electrical nerve stimulation (TENS) in terms of the wave form.

Policy:
FDA approved neuromuscular stimulator devices may be considered MEDICALLY NECESSARY when prescribed for disuse muscular atrophy from prolonged immobilization and that is present in the setting of an intact nerve supply to the muscle, including brain, spinal cord and peripheral nerves. 

A neuromuscular stimulator garment is considered NOT MEDICALLY NECESSARY.  

Neuromuscular stimulation is considered NOT MEDICALLY NECESSARY for: 

Neuromuscular electrical stimulation for the treatment of other conditions/diseases or using alternative methods, including, but not limited to, the following is investigational/unproven therefore is considered NOT MEDICALLY NECESSARY:

• Prevention of muscle atrophy (e.g., scoliosis)
• Treatment of pain
• H wave stimulation
• Threshold electrical stimulation

Any device utilized for this procedure must have FDA approval specific to the indication, otherwise it will be investigational/unproven therefore considered NOT MEDICALLY NECESSARY.

MEDICAL APPROPRIATENESS
Neuromuscular electrical stimulation is considered MEDICALLY NECESSARY if ANY ONE of the following are met:

• Treatment is indicated if ALL of the following are met:
  • Used to treat disuse muscular atrophy (for example: casting or splinting of limb, contracture due to scarring of soft tissue as in burn lesions, hip or knee replacement surgery)
  • Nerve supply to muscle is intact, including brain, spinal cord and peripheral nerves

Contraindications:
NMES/FES is contraindicated for members with SCI with ANY of the following: 

Rationale:
In 2010, Monaghan and colleagues reviewed available literature assessing the effectiveness of NMES in regards to quadricep strength before and after total knee replacement. The studies had no significant differences reported for maximum voluntary isometric torque or endurance between the NMES group and the control group. In one study there was a difference in quadriceps muscle activation in the group with NMES and exercise from the control group utilizing exercise alone. This difference was much more significant at 6 weeks than at 12 weeks. Further analysis was not possible related to the absence of raw data scores.  The authors concluded that the available studies preclude any conclusions regarding NMES quadriceps strengthening pre- and post-op total knee replacement.

In 2010, a study was conducted evaluating the effect of NMES on quadriceps muscle strength and activation in women with mild and moderate osteoarthritis by Palmieri-Smith and colleagues. The was a treatment and a non-treatment group. The treatment group received NMES 3 times a week for 4 weeks. At the conclusion of the study, no improvement was noted in the treatment group. 

In 2012 results of a post TKA NMES quadriceps study were published. This study conducted by Stevens-Lapsley and colleagues initiated NMES 48 hours post TKA in addition to standard rehabilitation. Subjects were randomly assigned to either NMES and standard rehabilitation or standard rehabilitation. Significant improvement in the NMES group was noted in quadriceps and hamstring strength at 3.5 weeks post op. There was also improved functional performance, knee extension and active range of motion noted.  Authors concluded that early addition of NMES reduced loss of quadriceps muscle strength and improved functional performance following TKA.  Results persisted through 52 weeks post op, but, were most notable in the first post operative month. As this was a small study with volumes not matched in both arms of the study, the authors stated further research is warranted regarding early intervention with NMES after TKA. 

Numerous clinical trials are currently on going regarding NMES. They include studies related to multiple sclerosis, cerebral palsy, hemiparetic patients and ICU associated weakness. Several studies have recently been completed with data not yet published. 

The principal outcomes associated with treatment of pain due to any cause may include: relief of pain, improved functional level, and return to work. Relief of pain is a subjective outcome that is typically associated with a placebo effect. Therefore, data from adequately powered, blinded, randomized controlled trials (RCTs) are required to control for the placebo effect, determine its magnitude, and determine whether any treatment effect from an electrical stimulation device provides a significant advantage over the placebo. 

Treatment with an electrical stimulation device must also be evaluated in general groups of patients against the existing standard of care for the condition being treated. For example, in patients with pain symptoms, treatment with an electrical stimulation device should be compared with other forms of conservative therapy such as splinting, rest, non-steroidal anti-inflammatory medications, physical therapy, or steroid injection.

SYSTEMATIC REVIEW
Williamson (2021) published a review of pre-clinical (animal) and clinical studies evaluating the H-Wave^® device in the treatment of acute, chronic, or post-surgical musculoskeletal pain or loss of function.¹ Sixteen studies were included in the review, however only nine of the studies reported clinical data (N = 6,789). The trials, small cohort studies and case reports are summarized below. The authors summarized study outcomes of reduced pain, improved function, and lower medication use with the device. The certainty of evidence assessed for all studies was low to moderate with study weaknesses including moderate risk of bias and lack of objective clinical findings noted. No pooled analyses were conducted. 

A systematic review with meta-analysis, supported in part by a device manufacturer (Electronic Waveform Lab, Inc.) was published in 2008 and reported on five studies using the H-Wave device for the treatment of pain.² However, conclusions based on this meta-analysis are limited by the lack of sufficient data from randomized, placebo-controlled studies and are based mainly upon results from case series. 

RANDOMIZED CONTROLLED TRIALS 
Two small RCTs (n = 23 and 31) evaluated the efficacy of H-wave electrical stimulation in the treatment of diabetic peripheral neuropathy, a follow-up survey reported outcomes of patients who continued H-wave electrical stimulation for more than one year, and one small study evaluated the effects of H-wave stimulation on range of motion and strength testing in patients who underwent rotator cuff reconstruction.^3,4,5,6 The generalizability of the findings in these studies is limited due to at least one of the following reasons:

• The small study population limited the ability to rule out the role of chance as an explanation of findings.
• The attrition of study subjects and blinding was either not reported or not adequately addressed in the analysis, potentially undermining comparability of treatment groups.

Definitions:
TENS: Transcutaneous Electrical Nerve Stimulator is a device used to treat chronic intractable pain, and pain associated with active or post-traumatic injury unresponsive to other standard pain therapies. The device is applied to the surface of the skin at the site of the pain. It consists of an electrical pulse generator, usually battery operated, connected by a wire to two or more electrodes. A programmable stimulator may be programmed in advance to stimulate at regular times or upon demand by the use of a hand held magnet over the stimulator. (Neuro Cybernetic Prosthesis System) 

MNS: Microcurrent Nerve Stimulator works on the same principal as TENS by delivering microcurrent instead of regular current. 

PENS: Percutaneous Nerve Stimulator is similar to TENS, with the exception that instead of electrodes attached to the skin near the pain area, in PENS, a needle is inserted into the pain site. 

PNT: Percutaneous neuromodulation therapy is a variant of PENS in which up to 10 fine filament electrodes are temporarily placed at specific anatomical landmarks in the back. Treatment regimens consist of 30-minute sessions, once or twice a week for 8 to 10 sessions. 

VNS: Implanted vagus nerve stimulation (VNS) devices have been used to treat patients with medically refractory partial-onset seizures for whom surgery is not recommended or for whom surgery has failed. Surgery for implantation of the VNS device is done with the patient under either general anesthesia or regional cervical block. Since right vagus nerve stimulation produces bradycardia, implantation is limited to left-sided unilateral implantations. Two spiral electrodes are implanted around the left vagus nerve within the carotid sheath, which are connected to an infraclavicular generator pack. A programmable stimulator may be programmed in advance to stimulate at regular times or upon demand by the use of a hand held magnet over the stimulator. (Neuro Cybernetic Prosthesis System) 

FNS: Functional Neuromuscular Stimulation attempts to replace stimuli from destroyed nerve pathways with electrical stimulation to the muscles. It is presumed that electric stimulation enables the spinal cord injured patient to stand or walk independently or to maintain healthy muscle tone and strength. 

NMES: Neuromuscular Electric Stimulator for disuse atrophy. NMES involves the use of a device that transmits an electrical impulse to activate muscle groups by way of electrodes. There are two broad categories of NMES. One type of device stimulates the muscle when the patient is in a resting state to treat muscle atrophy. The second type is used to enhance functional activity of neurologically impaired patients. 

Spinal Cord Stimulation for Chronic Pain: Electrodes are implanted in the epidural space to stimulate the dorsal column and treat chronic pain. 

DBS: Deep Brain Stimulation of the thalamus has been used as an alternative to permanent neuroablative procedures such as thalamotomy and pallidotomy for control of essential tremor, and tremors associated with Parkinson's disease.  It involves stereotactic placement of an electrode into the brain, which is attached to a temporary transcutaneous cable for short-term stimulation to validate treatment effectiveness.  Several days later a permanent subcutaneous programmable stimulator is implanted.  DBS of the globus pallidus and subthalamic nucleus has also been investigated for other symptoms of Parkinson's disease such as rigidity, bradykinesia or akinesia.  DBS is also FDA approved for the treatment of dystonia. 

H-Wave^® Electric Stimulation: This device is used for the treatment of pain related to a variety of etiologies. This is also used for wound healing. 

Sensory Stimulation for Coma Patients: Sensory stimulation is intended to enhance awakening and rehabilitative potential of coma patients. Treatment may be delivered in the hospital, the patient's home, or a nursing home by professionals including nurses, occupational therapist, physical therapist, speech language therapist and even by a trained family member. 

TES: Threshold Electric Stimulator as a treatment of motor disorders. Low intensity electrical stimulation is used to target spastic muscles during sleep at home. Although the exact mechanism of action is not known, it is presumed that it may increase muscle strength and joint mobility leading to improved voluntary motor function. This is used in children with spastic paraplegia related to cerebral palsy and also in those with other motor disorders, such as spina bifida. 

Sympathetic therapy as a treatment of chronic pain (i.e., Dynatron STS): Sympathetic therapy describes a type of electrical stimulation of the peripheral nerves that is designed to stimulate the sympathetic nervous system in an effort to 'normalize' the autonomic nervous system and alleviate chronic pain. Sympathetic therapy is not designed to treat local pain, but is designed to induce a systemic effect on sympathetically induced pain. 

Interferential current stimulation (IFC) is a type of electrical current treatment that uses paired electrodes of two independent medium-frequency alternating currents. The electrodes are arranged on the skin so the current flowing between each pair intersects at the underlying target. IFC has been investigated as a technique to reduce pain, improve range of motion, or promote local healing. 

Lymphavision^TM is an electrical stimulation device that stimulates smooth muscles thereby promoting lymphatic flow. It is described as a treatment for such conditions as diabetic foot syndrome and trophic ulcers, and prevention of deep vein thrombosis. 

TEJS: Transcutaneous electrical joint stimulation is the application of a signal-specific electrical current to the joint tissue to relive the signs and symptoms of osteoarthritis of the knee. Two electrode patches are worn for six to ten hours a day, preferably while the patient is sleeping. TEJS has been indicated as adjunctive therapy for patients who have failed NSAIDS, those with moderate to severe disease despite best medical therapy, and those with severe disease who are not surgical candidates for reasons such as morbid obesity and inappropriate age. 

PES: Pulsed electrical stimulation is provided by an electronic device that noninvasively delivers a low voltage, monophasic electrical field to the targeted area of pain. It is used to improve functional status and relieve pain related to osteoarthritis and rheumatoid arthritis unresponsive to other standard forms of treatment.

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