Archived Policies - Medicine


Surface Scanning Electromyography (EMG) (SEMG), Paraspinal Surface EMG, and Spinoscopy

Number:MED205.006

Effective Date:01-01-2010

End Date:09-14-2012

Coverage:

The following noninvasive electromyography (EMG) tests are considered experimental, investigational and unproven as techniques to evaluate, diagnose or monitor neck/back pain or any other neuromusculoskeletal condition:

  • surface EMG (SEMG) or surface scanning EMG, OR
  • paraspinal SEMG or paraspinal EMG, OR
  • spinoscopy.

Description:

Surface electromyography (SEMG) has been investigated as a technique to evaluate the physiological functioning of the back.  In contrast to anatomic imaging, SEMG records the summation of muscle activity from groups of muscles.  SEMG, a noninvasive procedure, is contrasted with needle EMG, an invasive procedure, in which the electrical activity of individual muscles is recorded.  

Paraspinal SEMG, also referred to as paraspinal EMG scanning, has been explored as a technique to evaluate abnormal patterns of electrical activity in the paraspinal muscles in patients with back pain symptoms such as spasm, tenderness, limited range of motion, or postural disorders. The technique is performed using one or an array of electrodes placed on the skin surface, with recordings made at rest, in various positions, or after a series of exercises. Recordings can also be made by using a handheld device, which is applied to the skin at different sites. Electrical activity can be assessed by computer analysis of the frequency spectrum (i.e., spectral analysis), amplitude, or root mean square of the electrical action potentials.  In particular, spectral analysis focusing on the median frequency has been used to assess paraspinal muscle fatigue during isometric endurance exercises.  Paraspinal SEMG is an office-based procedure that may be most commonly used by physiatrists or chiropractors.  SEMG devices approved by the U.S. Food and Drug Administration (FDA) include those that use a single electrode or a fixed array of multiple surface electrodes. The following clinical applications of the paraspinal SEMG have been proposed:

  • clarification of a diagnosis (i.e., muscle, joint, or disc disease),
  • select a course of medical therapy,
  • select a type of physical therapy,
  • pre-operative evaluation,
  • postoperative rehabilitation,
  • follow-up of acute low back pain,
  • evaluation of exacerbation of chronic low back pain, and
  • evaluation of pain management treatment techniques.  

Spinoscopy (Spinoscope®, Spinex Corp.) consists of SEMG with associated video-recordings that records vertebral movement and the corresponding muscular activity during movements of the back.

Rationale:

Validation of the use of SEMG as a clinical diagnostic technique involves a sequential three-step procedure as follows:

  1. The technical performance of the test compared to a gold standard, including determination of test, retest reliability, positive and negative predictive values.
  2. Data demonstrating how the results of the test may be used in the management of the patient.
  3. A determination of whether beneficial health outcomes occur as a result of the change in management.

The following discussion focuses on these three steps.

1. Technical Performance of the Test:

Several studies using different SEMG devices have suggested that paraspinal SEMG, in general, is a reliable technique, based on coefficients of variation or test/retest studies.  While reliability is an important initial diagnostic parameter, the reliability of a test does not necessarily relate to its clinical utility. A diagnostic test must be further evaluated against a gold standard. The gold standard for evaluating the electrical activity of muscles is needle electromyography. Ideally, one would like to see data comparing the results of SEMG, which tests groups of muscles, to needle electromyography, which evaluates individual muscles. No such articles were identified in a literature search, thus it is not known how, or if, the electrical activity of groups of muscles relates to any specific muscle pathology, as validated by needle EMG.  However, it is recognized that the pathology of individual muscles (i.e., radiculopathy, neuropathy, etc.) may represent a different process than the pathology of muscle groups (i.e., muscle strain, spasm, etc.), and thus SEMG may be considered by its advocates as a unique test for which there is currently no gold standard. Nevertheless, even if one accepts this premise, there are inadequate data to evaluate the diagnostic performance of SEMG.  For example, no articles were identified in the published peer-reviewed literature that established definitions of normal or abnormal SEMG.  In some instances, asymmetrical electrical activity may have been used to define abnormality; results may be compared to a “normative data base”.  However, there was no published literature defining what degree of asymmetry would constitute abnormality or how a normative database was established.

In the absence of a gold standard diagnostic test, correlation with the clinical symptoms and physical exam is critical.  De Luca has published a series of studies investigating a type of SEMG called the Back Analysis System (BAS), consisting of surface electrodes and other components to measure the electrical activity of muscles during isometric exercises designed to produce muscle fatigue.  Using physical exam and clinical history as a gold standard, the author found that BAS was able to accurately identify control and back pain patients 84% and 91% of the time, respectively, with the values increasing to 100% in some populations of patients. (Accuracy is the sum of true positive and true negative results.)  However, these studies were not designed as a clinical diagnostic tool per se, but were intended to investigate the etiology of back pain and to investigate muscular fatigue patterns in patients with and without back pain.  When used to monitor response to therapy, patients may have served as their own control. However, there are no data that analyze how changes in the SEMG correlate to clinical response, whether a clinical response in the face of persisting SEMG abnormalities suggests ongoing pathology, or whether persistent symptoms in the face of a normal SEMG represent malingering.

2. How Results of the Test Are Used in the Management of the Patient

Several articles describe the use of SEMG as an aid in classifying low back pain.  Much of the research in this application has focused on the use of spectral analysis to assess muscle fatigability. However, it is unclear how this information may be used in the management of the patient. For example, while the innovators of the BAS system indicate that SEMG can suggest potential therapies by distinguishing deconditioning from muscle inhibition secondary to pain-related behavior, no clinical studies describe the use of SEMG in suggesting therapy. In another application of SEMG, Arena and colleagues assessed the amplitude of SEMG recordings as a measure of paraspinal muscle tension in 66 patients and reported that the degree of muscle tension did not correlate with pain levels. These findings raised questions about the role of biofeedback, muscle relaxants, or other therapies designed to reduce muscle tension. While SEMG may be used to objectively document muscle spasm or other muscular abnormalities, it is unclear how such objective documentation would supplant or enhance clinical evaluation, or how this information would be used to alter the treatment plan.  Part of the difficulty in clinical interpretation is understanding to what extent the SEMG abnormalities are primary or secondary. In addition, as noted by the guidelines from the Agency for Healthcare Research and Quality (AHRQ, formerly the Agency for Health Care Policy and Research, AHCPR), no specific workup is recommended for acute low back pain without warning signs. 

In terms of the use of SEMG to monitor response to treatment, there are no data to demonstrate how the results of SEMG compare to clinical assessment, such as determining recommended activity levels or ability to return to work.

3. Whether Beneficial Health Outcomes Occur as a Result of the Change in Management

There are no data regarding the final health outcomes. For example, SEMG has been proposed as a technique to differentiate muscle spasm from muscle contracture, with muscle spasm treated with relaxation therapy, and contracture treated with stretching exercises. There are no data to validate that such treatment suggested by SEMG results in improved outcomes.

Spinoscopy

The value of Spinoscopy evaluation in diagnosing and monitoring patients with back problems and ultimately improving their outcomes has not been demonstrated in the published peer reviewed medical literature.

Conclusion

Surface EMG techniques have not been shown to be reliable or valid when compared to standard, conventional needle EMG studies.  A review of the MEDLINE database through February 2007 did not identify any studies published in the peer-reviewed literature that change the coverage position of this medical policy.

2009 Update

A search of peer reviewed literature through September 2009 identified no new clinical trial publications or any additional information that would change the coverage position of this medical policy.

Contract:

Each benefit plan, summary plan description or contract defines which services are covered, which services are excluded, and which services are subject to dollar caps or other limitations, conditions or exclusions. Members and their providers have the responsibility for consulting the member's benefit plan, summary plan description or contract to determine if there are any exclusions or other benefit limitations applicable to this service or supply. If there is a discrepancy between a Medical Policy and a member's benefit plan, summary plan description or contract, the benefit plan, summary plan description or contract will govern.

Coding:

None


Medicare Coverage:

The information contained in this section is for informational purposes only.  HCSC makes no representation as to the accuracy of this information.  It is not to be used for claims adjudication for HCSC Plans.

The Centers for Medicare and Medicaid Services (CMS) does not have a national Medicare coverage position.  Coverage may be subject to local carrier discretion.

A national coverage position for Medicare may have been developed or changed since this medical policy document was written.  See Medicare's National Coverage at <http://www.cms.hhs.gov>.

References:

Ahern, D.K., Follick, M.J., et al.  Reliability of lumbar paravertebral EMG assessment in chronic low back pain.  Archives of Physical Medicine Rehabilitation (1986) 67(10):762-5.

Cram, J.R., Lloyd, J., et al.  The reliability of EMG muscle scanning.   International Journal of Psychosomatics (1994) 41(1-4):41-5.

Gentempo, P. Kent, C.  Establishing medical necessity for paraspinal EMG scanning. Chiropractic: Journal of Chiropractic Research and Clinical Investigations (1990) 3(1):22-5.

De Luca, C.J.  Use of the surface EMG signal for performance evaluation of back muscles. Muscle Nerve (1993) 16(2):210-6.

Roy, S.H., Oddsson, L.I.  Classification of paraspinal muscle impairments by surface electromyography.  Physical Therapy (1998) 78(8):838-51.

Peach, J.P., McGill, S.M.  Classification of low back pain with the use of spectral electromyogram parameters.  Spine (1998) 23(10):1117-23.

Roy, S.H., De Luca, C.J., et al. Spectral electromyographic assessment of back muscles in patients with low back pain undergoing rehabilitation. Spine (1995) 20(1):38-48.

Bittman, B., Cram, J.R.  Surface electromyography: An electrophysiologic alternative in pain management.  Presented at American Pain Society (1992 October).

Ellestad, S.M., Nagle, R.V. et al. Electromyographic and skin resistance responses to osteopathic manipulative treatment for low-back pain.  Journal of  American Osteopathy Association (1988) 88(8):991-7.

Falkenberg, J., Podein, R.J., et al.  Surface EMG activity of the back musculature during axial spinal unloading using an LTX 3000 Lumbar Rehabilitation System.  Electromyography Clinical Neurophysiology (2001) 41(7):419-27.

Humphrey, A.R., Nargol, A.V., et al.  The value of electromyography of the lumbar paraspinal muscles in discriminating between chronic-low-back-pain sufferers and normal subjects.  Europe Spine Journal (2005) 14(2):175-84.

Cheung, J., Halbertsma, J.P., et al.  A preliminary study on electromyographic analysis of paraspinal musculature in idiopathic scoliosis.  Europe Spine Journal (2005) 14(2):130-7.

Paraspinal Surface Electromyography (EMG) to Evaluate and Monitor Back Pain.  Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (2009 October) 2.01.35.

Policy History:

1/1/2010          Revised/Updated Entire Document, no change in experimental, investigational, and unproven coverage position.

5/15/2007        Revised/Updated Entire Document

10/2003           Codes Revised/Added/Deleted

8/15/2003        Revised/Updated Entire Document

1/1998             Revised/Updated Entire Document

5/1996             Revised/Updated Entire Document

1/1995             Revised/Updated Entire Document

4/1994             Revised/Updated Entire Document

5/1990             New Medical Document

Archived Document(s):

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