Description
Both invasive and noninvasive electrical bone growth stimulators have been investigated as an adjunct to spinal fusion surgery, with or without associated instrumentation, to enhance the probability of obtaining a solid spinal fusion. Noninvasive devices have also been investigated in patients who are at normal risk of failed fusion and to treat a failed fusion.

For individuals who are at high risk of lumbar spinal fusion surgery failure who receive invasive or noninvasive electrical bone growth stimulation, the evidence includes systematic reviews, a TEC Assessment, and randomized controlled trials. Relevant outcomes are symptoms, change in disease status, and functional outcomes. Results from these trials have indicated that in patients with risk factors for failed fusion surgery, either invasive or noninvasive electrical bone stimulation increases the fusion rate. The evidence is sufficient to determine that the technology results in a meaningful improvement in the net health outcome. 

For individuals who have failed lumbar spinal fusion surgery who receive noninvasive electrical bone growth stimulation, the evidence includes a TEC Assessment and studies with patients serving as their own controls. Relevant outcomes are symptoms, change in disease status, and functional outcomes. Data have shown that noninvasive electrical stimulation improves fusion rates in this population. The evidence is sufficient to determine that the technology results in a meaningful improvement in the net health outcome.

For individuals who are undergoing cervical spinal fusion surgery or have failed cervical spine fusion who receive invasive or noninvasive electrical bone growth stimulation, the evidence includes a randomized controlled trial. Relevant outcomes are symptoms, change in disease status, and functional outcomes. The only controlled trial published to date had methodologic limitations, and the efficacy of electrical stimulation in the cervical spine has not been established. An open-label multicenter cohort study provided evidence to demonstrate that patients at high risk for arthrodesis following anterior cervical discectomy and fusion procedures reported statistically significant improvements in fusion rates with pulsed electromagnetic field stimulation. However, limitations in the study design, including use of a historical control group, lack of blinding, and no restrictions on surgical methods used by surgeons, preclude definitive assessments of treatment efficacy. The evidence is insufficient to determine the effects of the technology on health outcomes.

Background
Electrical Bone Growth Stimulators
Both invasive and noninvasive electrical bone growth stimulators have been investigated as an adjunct to spinal fusion surgery, with or without associated instrumentation, to enhance the probability of obtaining a solid spinal fusion. Noninvasive devices have also been investigated to treat a failed fusion.

Electrical and electromagnetic fields can be generated and applied to bones through surgical, noninvasive, and semi-invasive methods.

Invasive Stimulators
Invasive devices require surgical implantation of a current generator in an intramuscular or subcutaneous space, with an accompanying electrode implanted within the fragments of bone graft at the fusion site. The implantable device typically remains functional for six to nine months after implantation, and although the current generator is removed in a second surgical procedure when stimulation is completed, the electrode may or may not be removed. Implantable electrodes provide constant stimulation at the nonunion or fracture site but carry increased risks associated with implantable leads.

Noninvasive Stimulators
Noninvasive electrical bone growth stimulators generate a weak electrical current within the target site using either pulsed electromagnetic fields, capacitive coupling, or combined magnetic fields. In capacitive coupling, small skin pads/electrodes are placed on either side of the fusion site and are worn for 24 hours a day until healing occurs, or for up to 9 months. In contrast, pulsed electromagnetic fields are delivered via treatment coils that are placed into a back brace or directly onto the skin and are worn for six to eight hours a day for three to six months. Combined magnetic fields deliver a time-varying magnetic field by superimposing the time-varying field onto an additional static magnetic field. This device involves 30 minutes of treatment daily for 9 months. Patient compliance may be an issue with externally worn devices.

Semi-Invasive Stimulators
Semi-invasive (semi-implantable) stimulators use percutaneous electrodes and an external power supply, obviating the need for a surgical procedure to remove the generator when treatment is finished.

Regulatory Status 
The following implantable device was approved by the U.S. Food and Drug Administration (FDA) through the premarket approval process: 

The following noninvasive bone growth stimulators have been approved by FDA through the premarket approval process:  

• In 1999, the SpinalPak^® bone growth stimulator system (Biolectron, a subsidiary of Electro-Biology), a capacitive coupling system, was approved for use as an adjunct to primary lumbar spinal fusion at 1 or 2 levels. 
• In 1979, the EBI Bone Healing System^® (Biolectron, a subsidiary of Electro-Biology), a pulsed electromagnetic field system, was approved for nonunions, failed fusions, and congenital pseudoarthroses. The device is secured with a belt around the waist. 
• In 1994, the SpinaLogic Bone Growth Stimulator^® (Regentek, a division of dj Orthopedics [formerly OrthoLogic]) was approved as a combined magnetic field portable device. This device is secured with a belt around the waist.
• In 1996, the Spinal-Stim Lite^® (Orthofix) was approved as a spinal adjunct to the Physio-Stim^®. The Spinal-Stim Lite^® device was approved to increase the probability of fusion success and as a nonoperative treatment for the salvage of failed spinal fusion, where a minimum of 9 months has elapsed since the last surgery.
• In 2004, the Stim^® (Orthofix), a pulsed electromagnetic field system, was approved as an adjunct to cervical fusion surgery in patients at high risk for nonfusion.

No semi-invasive electrical bone growth stimulator devices were identified with FDA approval or clearance.

FDA product codes: LOE (invasive bone growth stimulator), LOF (noninvasive bone growth stimulator).

Policy
Either invasive or noninvasive methods of electrical bone growth stimulation may be considered MEDICALLY NECESSARY as an adjunct to lumbar spinal fusion surgery in patients at high risk for fusion failure, defined as any one of the following criteria:

• One or more previous failed spinal fusion(s)
• Grade III or worse spondylolisthesis
• Fusion to be performed at more than one level
• Current tobacco use
• Diabetes
• Renal disease
• Alcoholism
• Steroid use

Noninvasive electrical bone stimulation may be considered MEDICALLY NECESSARY as a treatment of patients with failed lumbar spinal fusion. Failed spinal fusion is defined as a spinal fusion that has not healed at a minimum of six months after the original surgery, as evidenced by serial X-rays over a course of three months.

Semi-invasive electrical stimulation is investigational and/or unproven and therefore considered NOT MEDICALLY NECESSARY as an adjunct to lumbar fusion surgery and for failed lumbar fusion.

Invasive, semi-invasive and noninvasive electrical stimulation are investigational and/or unproven and therefore considered NOT MEDICALLY NECESSARY as an adjunct to cervical fusion surgery and for failed cervical spine fusion.

Benefit Application
BlueCard^®/National Account Issues
State or federal mandates (e.g., FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and, thus, these devices may be assessed only on the basis of their medical necessity.

While invasive electrical stimulation will be billed as a component of the hospital bill, noninvasive devices may be adjudicated according to the benefits for durable medical equipment.

Rationale
Evidence reviews assess the clinical evidence to determine whether the use of technology improves the net health outcome. Broadly defined, health outcomes are the length of life, quality of life, and ability to function, including benefits and harms. Every clinical condition has specific outcomes that are important to patients and managing the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcome is a balance of benefits and harms.

To assess whether the evidence is sufficient to draw conclusions about the net health outcome of technology, two domains are examined: the relevance, and quality and credibility. To be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative at a comparable intensity. For some conditions, the alternative will be supportive care or surveillance. The quality and credibility of the evidence depend on study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial (RCT) is preferred to assess efficacy; however, in some circumstances, nonrandomized studies may be adequate. RCTs are rarely large enough or long enough to capture less common adverse events and long-term effects. Other types of studies can be used for these purposes and to assess generalizability to broader clinical populations and settings of clinical practice.

Promotion of greater diversity and inclusion in clinical research of historically marginalized groups (e.g., people of color [African American, Asian, Black, Latino and Native American]; LGBTQIA [lesbian, gay, bisexual, transgender, queer, intersex, asexual); women; and people with disabilities [physical and invisible]) allows policy populations to be more reflective of and findings more applicable to our diverse members. While we also strive to use inclusive language related to these groups in our policies, use of gender-specific nouns (e.g., women, men, sisters, etc.) will continue when reflective of language used in publications describing study populations.

Invasive Electrical Bone Growth Stimulation in Individuals at High-Risk of Lumbar Spinal Fusion Surgery Failure
Clinical Context and Therapy Purpose
The purpose of invasive electrical bone growth stimulation in individuals at high risk of lumbar spinal fusion surgery failure is to provide a treatment option that is an alternative to or an improvement on existing therapies.

The question addressed in this evidence review is: Does the use of invasive electrical bone growth stimulation improve the net health outcome in individuals at high risk of lumbar spinal fusion surgery failure?

The following PICO was used to select literature to inform this review.

Populations
The relevant population of interest are individuals at high risk of lumbar spinal fusion surgery failure.

Interventions
The therapy being considered is invasive electrical bone growth stimulation.

Comparators
The following practice is currently being used to treat individuals at high risk of lumbar spinal fusion surgery failure: lumbar spinal fusion surgery without invasive electrical bone growth stimulation.

Outcomes
The general outcomes of interest are symptoms, change in disease status, and functional outcomes.

Study Selection Criteria
Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.
• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.
• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.
• Studies with duplicative or overlapping populations were excluded.

Review of Evidence
Randomized Controlled Trials
Instrumented Spinal Fusion
Kucharzyk (1999) reported on a controlled, prospective, nonrandomized trial of implantable electrical stimulation in patients undergoing instrumented posterior spinal fusion with pedicle screws.¹ A series of 65 patients who did not receive electrical stimulation were compared with a later series of similar patients who did receive implantable electrical stimulation. The fusion success rate was 95.6% in the stimulated group and 87% in the nonstimulated group, a statistically significant difference. It appears that all patients had at least 1 or more high-risk factors for failed fusion, including smoking history, prior surgery, multiple fusion levels, and diabetes. While this trial supported the use of electrical stimulation as an adjunct to instrumented posterior lumbar fusion, it did not specifically identify the outcomes in patients considered to be at low-risk for failed fusion.

Rogozinski and Rogozinski (1996) reported on the outcomes of 2 consecutive series of patients undergoing posterolateral fusions with autologous bone graft and pedicle screw fixation.² The first series of 41 patients was treated without electrical bone growth stimulation, while the second group of 53 patients received invasive electrical stimulation. Those receiving electrical stimulation reported a 96% fusion rate, compared with an 85% fusion rate in the nonstimulated group. The fusion rate for patients receiving stimulation versus no stimulation was also significantly higher among those considered at high- risk due to previous back surgery or multiple fusion levels. No significant increase in the fusion rate was noted among nonsmokers (ie, without a risk factor), but comparative fusion rates for all patients without high-risk factors were not presented.

Noninstrumented Spinal Fusion
Andersen et al. (2009) published 2-year radiographic and functional outcomes from a European multicenter RCT of direct current (DC) stimulation with the SpF-XL IIb for posterolateral lumbar spinal fusion in 98 patients older than age 60 years.³ This age group has decreased fusion potential. Also, instrumentation was not used due to risks related to longer operating times and screw loosening due to osteoporosis. All patients received fresh frozen allograft bone mixed with autograft obtained from the decompression procedure and were braced for months after surgery. Dummy electrodes were placed in the control group to allow blinded radiographic evaluation, but patients and surgeons were not blinded to treatment group. Stimulator-specific complications included 3 cases of hematoma after removal of the battery and 2 patients with pain at the site of the subcutaneous pocket. Three patients dropped out before the 1-year radiologic evaluation, 1 patient died, and 25 other patients did not complete the functional outcome questionnaires, resulting in 70% follow-up at 2 years. The percentage of dropouts was similar for both treatments; patients who missed their 2-year evaluation had poorer outcomes on the Dallas Pain Questionnaire at the 1-year follow-up. Blinded evaluation of fusion by computed tomography scan indicated the same low percentage of cases with fusion in both groups (33%). Fusion rates by plain radiographs were 57% (24/42) in the control group and 64% (27/42) in the standard direct current (DC)-stimulation group. Patients who achieved solid fusion had a better functional outcome and lower pain scores at their last follow-up. At 2-year follow-up, electrical stimulation was associated with improved functional outcomes on 3 of 4 Dallas Pain Questionnaire subscales (daily activity, work/leisure, social interest) but not for the Low Back Pain Rating Scale or the 36-Item Short-Form Health Survey. These functional results have a high potential for bias due to the dropout rate among patients with poorer outcomes and the unequal patient expectation in this unblinded study.

Andersen et al. (2010) evaluated the bone quality of the fusion mass in 80 (82%) of 98 the patients previously described who underwent dual-energy x-ray absorptiometry scanning to evaluate bone mineral density at the 1-year follow-up.⁴ This report described 40 (n = 36) and 100 (n = 8) microampere (μA) DC-stimulation compared with a nonstimulated control condition (n = 36). Fusion rates determined by computed tomography scanning at the 2-year follow-up were 34% in the control group and 34% and 43% in the 40 and 100 μA groups, respectively (p = not significant). Patients classified as fused after 2 years had significantly higher fusion mass bone mineral density at 1 year (0.592 g/cm2 vs 0.466 g/cm2), but DC electrical stimulation did not improve fusion mass bone quality (0.483 g/cm2 for 40 μA vs 0.458 g/cm2 for 100 μA vs 0.512 g/cm2 for controls). Using linear regression, fusion mass bone quality was significantly influenced by sex, patient age, bone density of the remaining part of the lumbar spine, amount of bone graft applied, and smoking status.

Section Summary: Invasive Electrical Bone Growth Stimulation in Individuals at High-Risk of Lumbar Spinal Fusion Surgery Failure
Two RCTs have evaluated implantable electrical stimulation for bone growth stimulation, 1 in instrumented spinal fusion and 1 in noninstrumented spinal fusion, in patient populations at risk for failed fusion surgery. Although the studies had some risk for bias due to differential dropout rates, both showed improved fusion with electrical stimulation on blinded intermediate measures of radiographic fusion. These findings support the conclusion of improved functional outcomes with electrical stimulation.

Noninvasive Electrical Bone Growth Stimulation in Individuals at High-Risk of Lumbar Spinal Fusion Surgery Failure
Clinical Context and Therapy Purpose
The purpose of noninvasive electrical bone growth stimulation in individuals at high risk of lumbar spinal fusion surgery failure is to provide a treatment option that is an alternative to or an improvement on existing therapies.

The question addressed in this evidence review is: Does the use of noninvasive electrical bone growth stimulation improve the net health outcome in individuals at high risk of lumbar spinal fusion surgery failure?

The following PICO was used to select literature to inform this review.

Populations
The relevant population of interest are individuals at high risk of lumbar spinal fusion surgery failure.

Interventions
The therapy being considered is noninvasive electrical bone growth stimulation.

Comparators
The following practice is currently being used to treat individuals at high risk of lumbar spinal fusion surgery failure: lumbar spinal fusion surgery without noninvasive electrical bone growth stimulation.

Outcomes
The general outcomes of interest are symptoms, change in disease status, and functional outcomes.

Study Selection Criteria
Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.
• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.
• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.
• Studies with duplicative or overlapping populations were excluded.

Review of Evidence
Randomized Controlled Trials
Goodwin et al. (1999) reported on the results of a study that randomized 179 patients undergoing lumbar spinal fusions to receive or not to receive capacitively coupled electrical stimulation.⁵ A variety of surgical procedures, both with and without instrumentation were used, and patients were not limited to high-risk groups. The overall successful fusion rate was 84.7% for those in the active treatment group compared with 64.9% in the placebo group, which was a statistically significant difference. While the actively treated group reported increased fusion success for all stratification groups (i.e., according to fusion procedure, single or multilevel fusion, smoking or nonsmoking group), in many instances, the differences were not statistically significant because of small numbers. For example, patients who had undergone previous surgery, smokers, and those with multilevel fusion were included, among the subgroups in which there was no significant difference in fusion rates between the active and placebo groups. Also, there were numerous dropouts in the study and a 10% noncompliance rate among those wearing the external device for up to 9 months.

Mooney (1990) reported on the results of a double-blind study that randomized 195 patients undergoing initial attempts at interbody lumbar fusions with or without fixation to receive or not to receive pulsed electromagnetic field stimulation.⁶ Patients were not limited to high-risk groups. In the active treatment group, the success rate was 92%, compared with 65% in the placebo group. On subgroup analysis, the treated group consistently reported an increased success rate. Subgroups included graft type, presence or absence of internal fixation, or presence or absence of smoking.

Linovitz et al. (2002) conducted a double-blind RCT that assigned 201 patients undergoing 1- or 2-level posterolateral fusion without instrumentation to active or placebo electrical stimulation using a combined magnetic field device.⁷ Unlike capacitively coupled or pulsed electromagnetic field devices, the combined magnetic field device requires a single, 30-minute treatment per day with the device centered on the fusion site. Patients were treated for 9 months. Among all patients, 64% of those in the active group showed fusion at 9 months compared with 43% of those with placebo devices, which was a statistically significant difference. On subgroup analysis, there was a significant difference among women, but not men.

The studies by Mooney (1990) and Linovitz et al. (2002) both excluded patients with severe osteoporosis, and in the study by Goodwin et al. (1999), patients with osteoporosis of unspecified severity were excluded.^6,5,7 None of the studies mentioned steroid use; however, authors of 2 articles summarizing the available evidence on inhibition of bone healing8, and the effects of drugs on bone healing⁹ agreed that long-term (> 1 week) steroid use has an inhibitory effect on bone healing. Thus, steroid use is added as another factor that results in a high-risk of nonfusion.

Section Summary: Noninvasive Electrical Bone Growth Stimulation in Individuals at High-Risk of Lumbar Spinal Fusion Surgery Failure
Three RCTs identified assessed noninvasive electrical bone growth stimulation for spinal fusion surgery in patients at risk of fusion failure. Across the studies, treatment success rates were higher in groups receiving electrical stimulation.

Noninvasive Electrical Bone Growth Stimulation in Individuals With Failed Lumbar Spinal Fusion Surgery
Clinical Context and Therapy Purpose
The purpose of noninvasive electrical bone growth stimulation in individuals with failed lumber spinal fusion surgery is to provide a treatment option that is an alternative to or an improvement on existing therapies.

The question addressed in this evidence review is: Does the use of noninvasive electrical bone growth stimulation improve the net health outcome in individuals with failed lumbar spinal fusion surgery?

The following PICO was used to select literature to inform this review.

Populations
The relevant population of interest are individuals with failed lumbar spinal fusion surgery.

Interventions
The therapy being considered is noninvasive electrical bone growth stimulation.

Comparators
The following practice is currently being used to treat individuals with failed lumbar spinal fusion surgery: lumbar spinal fusion surgery without noninvasive electrical bone growth stimulation.

Outcomes
The general outcomes of interest are symptoms, change in disease status and functional outcomes.

Study Selection Criteria
Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.
• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.
• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.
• Studies with duplicative or overlapping populations were excluded.

Review of Evidence
A TEC Assessment (1993) evaluated noninvasive electrical bone stimulation as a treatment of failed spinal fusion surgery (i.e., salvage therapy).¹⁰ The TEC Assessment concluded that data from uncontrolled studies of patients with failed spinal fusion surgery suggested that noninvasive electrical stimulation results in a significantly higher fusion rate. The lack of controlled clinical trials was balanced by the fact that these patients served as their own controls.

Section Summary: Noninvasive Electrical Bone Growth Stimulation in Individuals With Failed Lumbar Spinal Fusion Surgery
A TEC Assessment of uncontrolled studies suggested that noninvasive electrical stimulation results in a significantly higher fusion rate than no electrical stimulation in patients with failed lumbar spinal fusion surgery.

Invasive or Noninvasive Electrical Bone Growth Stimulation in Cervical Spinal Fusion Surgery
Clinical Context and Therapy Purpose
The purpose of electrical bone growth stimulation in cervical spinal fusion surgery is to provide a treatment option that is an alternative to or an improvement on existing therapies.

The question addressed in this evidence review is: Does the use of electrical bone growth stimulation improve the net health outcome in individuals undergoing cervical spinal fusion surgery or with failed cervical spinal fusion surgery?

The following PICO was used to select literature to inform this review.

Populations
The relevant population of interest are individuals undergoing cervical spinal fusion surgery or with failed cervical spinal fusion surgery.

Interventions
The therapy being considered is invasive or noninvasive electrical bone growth stimulation.

Comparators
The following practice is currently being used to treat individuals undergoing cervical spinal fusion surgery or with failed cervical spinal fusion surgery: cervical spinal fusion surgery without electrical bone growth stimulation or conservative management.

Outcomes
The general outcomes of interest are symptoms, change in disease status, and functional outcomes.

Study Selection Criteria
Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs.
• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.
• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.
• Studies with duplicative or overlapping populations were excluded.

Review of Evidence
Randomized Controlled Trials
Foley et al. (2008) published results from the industry-sponsored investigational device exemption trial of pulsed electromagnetic field stimulation as an adjunct to anterior cervical discectomy and fusion with anterior cervical plates and allograft interbody implants.¹¹ This trial described results using the Cervical-Stim device (Orthofix) that received premarket approval from the FDA in 2004.¹² A total of 323 patients were randomized, 163 to pulsed electromagnetic field stimulation and 160 to no stimulation. All patients were active smokers (> 1 pack of cigarettes per day, 164 patients) or were undergoing multilevel anterior cervical discectomy and fusion (192 patients). Patients with a pertinent history of trauma, previous posterior cervical approach or revision surgery, certain systemic conditions or steroid use, and regional conditions (e.g., Paget disease, spondylitis) were excluded. Beginning 1 week after surgery, patients in the treatment group wore the Cervical-Stim device for 4 hours a day for 3 months.

Efficacy was measured by radiographic analysis at 1, 2, 3, 6, and 12 months. At 6 months, 122 patients in the treatment group and 118 in the control group were evaluable; 15 in the pulsed electromagnetic field group and 13 in the control group voluntarily withdrew, 7 in the pulsed electromagnetic field group and 1 control violated study protocol, and 19 in the pulsed electromagnetic field group and 28 controls had inevaluable radiographs or radiographs not taken within 2 weeks of the 6-month postoperative window. Fusion rates for the 240 (74%) evaluable patients at 6 months were 83.6% for the pulsed electromagnetic field group and 68.6% for the control group (p = 0.007). By intention-to-treat analysis, assuming that nonevaluable patients did not have fusion, pulsed electromagnetic field, and control group fusion rates were 65.6% and 56.3%, respectively; these rates did not differ significantly (p = 0.084). The FDA analysis, however, indicated that the results at 6 months still differed statistically in sensitivity analysis performed with the last observation carried forward or with all missing data imputed as nonfusion. Of 245 patients available for follow-up at 12 months, fusion was achieved in 116 (92.8%) of 125 pulsed electromagnetic field patients and 104 (86.7%) of 120 control patients; these rates did not differ significantly (p = 0.113). Patient compliance, which was automatically monitored by the device, was assessed at each visit; however, compliance data were not reported in the article.

Clinical outcomes were not reported in the 2008 publication but were reported to the FDA. With clinical success defined as no worsening in neurologic function, an improvement in pain assessment on the visual analog scale, and no worsening in Neck Disability Index score, the study found no statistically significant differences between groups in the percentages of subjects considered a clinical success at 6 months (p = 0.85) or 12 months (p = 0.11). The marginal difference in fusion rates by intention-to-treat analysis at 6 months, nonsignificant difference in fusion rates at 12 months, and lack of difference in functional outcomes at either 6 or 12 months did not support the efficacy of this device.

Uncontrolled Studies
Coric et al. (2018) published results from an industry-sponsored multicenter cohort study of pulsed electromagnetic field treatment in patients at high-risk of cervical arthrodesis following anterior cervical discectomy and fusion procedures.¹³ The trial described results using the Cervical-Stim device (Orthofix) for 274 patients enrolled across 3 institutions. All patients had 1 or more risk factors, defined as nicotine user, osteoporosis, diabetes, age greater than 65 years or greater than 50 years, for pseudoarthrosis, and were treated with pulsed electromagnetic field stimulation for 3 to 6 months. A historical control group was generated from a post hoc analysis of high-risk subjects from the original U.S. Food and Drug Administration (FDA) investigational device exemption trial. The primary endpoint was bone fusion rates as assessed at 6 and 12 months by the treating surgeon not blinded to clinical symptoms and outcomes for subjects. At 6 months, statistically significant improvements in fusion rates were found for patients falling into the following risk factor groups with at least 1 risk factor for: age over 50 years and 2-level arthrodesis (p = 0.002); age over 50 years and 3-level arthrodesis (p < 0.001); age over 65 years and 2-level arthrodesis (p = 0.009); and age over 65 years and 3-level arthrodesis (p = 0.002). Likewise, at 12 months, statistically significant improvements in fusion rates were found for patients falling into the following risk factor groups with at least 1 risk factor for: age over 50 years and 2-level arthrodesis (p = 0.002); age over 50 years and 3-level arthrodesis (p < 0.001); age over 65 years and 2-level arthrodesis (p = 0.001); and age over 65 years and 3-level arthrodesis (p < 0.001). Study limitations included the use of a historical control group from the original investigational device exemption trial instead of a prospective control group, surgeons who were not blinded to clinical symptoms and outcomes, and surgeons who were not restricted to the surgical procedures used during the study.

Section Summary: Invasive or Noninvasive Electrical Bone Growth Stimulation in Cervical Spinal Fusion Surgery
One RCT evaluating electrical bone growth stimulation was identified. Due to methodologic limitations in the only controlled trial published to date, the efficacy of electrical stimulation has not yet been established. An open-label multicenter cohort study provided evidence to demonstrate that patients at high-risk for arthrodesis following anterior cervical discectomy and fusion procedures reported statistically significant improvements in fusion rates with pulsed electromagnetic field stimulation. However, limitations in the study design, including use of a historical control group, lack of blinding, and no restrictions on surgical methods used by surgeons, preclude definitive assessments of the efficacy of pulsed electromagnetic field treatment in this high-risk population. Randomized controlled trials are required to establish the effectiveness of pulsed electromagnetic field treatment to improve cervical fusion rates.

The purpose of the following information is to provide reference material. Inclusion does not imply endorsement or alignment with the evidence review conclusions.

Clinical Input From Physician Specialty Societies and Academic Medical Centers
While the various physician specialty societies and academic medical centers may collaborate with and make recommendations during this process, through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the physician specialty societies or academic medical centers, unless otherwise noted.

2011 Input
In response to requests, input was received from 2 physician specialty societies and 3 academic medical centers while this policy was under review in 2011. Input agreed with the criteria for high-risk of fusion failure of the lumbar spine. Input on electrical stimulation for the cervical spine was mixed; specifically, some reviewers input agreed that data do not demonstrate improved outcomes with use of electrical stimulation in cervical spine fusion surgery. Most reviewers agreed that the large number of dropouts, nonsignificant difference in fusion rates by intention-to-treat analysis, and lack of data on functional outcomes (e.g., pain, return to usual activity) limited interpretation of the published study results.

Practice Guidelines and Position Statements
Guidelines or position statements will be considered for inclusion in Supplemental Information if they were issued by, or jointly by, a U.S. professional society, an international society with U.S. representation, or National Institute for Health and Care Excellence (NICE). Priority will be given to guidelines that are informed by a systematic review, include strength of evidence ratings, and include a description of management of conflict of interest.

North American Spine Society
In 2016, the North American Spine Society issued a coverage recommendation for electrical bone growth stimulators based on a systematic review of the evidence, which stated the following:¹⁴

1. "For augmentation of spinal fusion in any and all regions of the spine including occipital-cervical, cervical, cervicothoracic, thoracic, thoracolumbar, lumbar and lumbosacral spinal regions in patients at high-risk for the development of pseudarthrosis (i.e., nonunion) who exhibit one or more of the following:
   1. Are undergoing spinal fusion of two or more motion segments (3 vertebrae)
   2. Are undergoing a revision spinal fusion (e.g., repeat surgery for a previously unhealed fusion attempt)
   3. Are smokers who cannot stop smoking in preparation for fusion due to the nature of the underlying condition (e.g., acute traumatic fracture)
   4. Exhibit one or more of the following comorbidities when undergoing primary lumbar fusion:
      1. Diabetes
      2. Inflammatory arthritis (e.g., rheumatoid arthritis) that has required long-term corticosteroid therapy
      3. Immunocompromised (e.g., undergoing chemotherapy and radiation therapy to the spine, hypogammaglobulinemia, granulocytopenia, acquired immune deficiency syndrome, chronic granulomatous disease)
      4. Systemic vascular disease
      5. Osteopenia or osteoporosis
2. In the lumbar spine, the following forms of electrical stimulation are indicated in high-risk patients with the specific techniques outlined. In all other regions of the spine, coverage for the same indications is recommended although there is less supporting evidence.
   1. DCS [direct current stimulation: electrodes implanted within or very close to the location of the desired fusion] and CCS [capacitance coupling stimulation; 2 electrodes placed on the skin over the fusion site] for posterolateral fusion using autograft and extender
   2. PEMFS [pulsed electromagnetic field stimulation: coils that produce a time-varying magnetic field around the area of the desired fusion] for lumbar interbody fusion"

American Association of Neurological Surgeons and Congress of Neurological Surgeons
In 2014, updated guidelines from the American Association of Neurological Surgeons and the Congress of Neurological Surgeons based on a systematic review that included conflict of interest declaration, indicated that there was no evidence published after their 2005 guidelines that conflicts with the previous recommendations on bone growth stimulation.¹⁵

Based on a single-level II study (2009), the routine use of direct current stimulation in patients older than age 60 years was not recommended. Use of direct current stimulation was recommended as an option for patients younger than 60 years of age, based on level III and IV studies showing a positive impact on fusion rate. However, concerns about the level III study were that it was a poorly designed and poorly conducted cohort study consisting of an exceedingly small heterogeneous population of patients, and the overall recommendation was level C. There was insufficient evidence to recommend for or against the use of pulsed electromagnetic field stimulation as a treatment alternative to revision surgery in patients presenting with pseudoarthrosis following posterolateral lumbar fusion (single-level IV study). No additional studies investigating the efficacy of capacitively coupled electrical stimulation were identified.

The two medical associations also issued guidelines in 2005 that stated there was class II and III evidence (nonrandomized comparative trials and case series):

"… to support the use of direct current stimulation or [capacitive coupled stimulation] for enhancing fusion rates in high-risk patients undergoing lumbar PLF. A beneficial effect on fusion rates in patients not at ‘high risk' has not been convincingly demonstrated, nor has an effect been shown for these modalities in patients treated with interbody fusion. There is limited evidence both for and against the use of pulsed electromagnetic fields for enhancing fusion rates following PLF. Class II and III medical evidence supports the use of pulsed electromagnetic fields for promoting arthrodesis following interbody fusion. Although some studies have purported to demonstrate functional improvement in some patient subgroups, other studies have not detected differences. All of the reviewed studies are significantly flawed by the use of a four-point patient satisfaction scale as the primary outcome measure. This outcome measure is not validated. Because of the use of this flawed outcome measure and because of the conflicting results reported in the better-designed studies that assess functional outcome, there is no consistent medical evidence to support or refute use of these devices for improving patient outcomes."¹⁶

U.S. Preventive Services Task Force Recommendations
Not applicable

Ongoing and Unpublished Clinical Trials
A search of ClinicalTrials.gov in March 2023 did not identify any ongoing or unpublished trials that would likely influence this review.

References   

1. Kucharzyk DW. A controlled prospective outcome study of implantable electrical stimulation with spinal instrumentation in a high-risk spinal fusion population. Spine (Phila Pa 1976). Mar 01 1999; 24(5): 465-8; discussion 469. PMID 10084185
2. Rogozinski A, Rogozinski C. Efficacy of implanted bone growth stimulation in instrumented lumbosacral spinal fusion. Spine (Phila Pa 1976). Nov 01 1996; 21(21): 2479-83. PMID 8923635
3. Andersen T, Christensen FB, Egund N, et al. The effect of electrical stimulation on lumbar spinal fusion in older patients: a randomized, controlled, multi-center trial: part 2: fusion rates. Spine (Phila Pa 1976). Oct 01 2009; 34(21): 2248-53. PMID 19934803
4. Andersen T, Christensen FB, Langdahl BL, et al. Fusion mass bone quality after uninstrumented spinal fusion in older patients. Eur Spine J. Dec 2010; 19(12): 2200-8. PMID 20429017
5. Goodwin CB, Brighton CT, Guyer RD, et al. A double-blind study of capacitively coupled electrical stimulation as an adjunct to lumbar spinal fusions. Spine (Phila Pa 1976). Jul 01 1999; 24(13): 1349-56; discussion 1357. PMID 10404578
6. Mooney V. A randomized double-blind prospective study of the efficacy of pulsed electromagnetic fields for interbody lumbar fusions. Spine (Phila Pa 1976). Jul 1990; 15(7): 708-12. PMID 2218718
7. Linovitz RJ, Pathria M, Bernhardt M, et al. Combined magnetic fields accelerate and increase spine fusion: a double-blind, randomized, placebo controlled study. Spine (Phila Pa 1976). Jul 01 2002; 27(13): 1383-9; discussion 1389. PMID 12131732
8. Gaston MS, Simpson AH. Inhibition of fracture healing. J Bone Joint Surg Br. Dec 2007; 89(12): 1553-60. PMID 18057352
9. Pountos I, Georgouli T, Blokhuis TJ, et al. Pharmacological agents and impairment of fracture healing: what is the evidence?. Injury. Apr 2008; 39(4): 384-94. PMID 18316083
10. Blue Cross Blue Shield Association Technology Evaluation Center (TEC). Electrical bone growth stimulation in association with spinal fusion surgery (noninvasive method). TEC Evaluations. 1993:1-12.
11. Foley KT, Mroz TE, Arnold PM, et al. Randomized, prospective, and controlled clinical trial of pulsed electromagnetic field stimulation for cervical fusion. Spine J. 2008; 8(3): 436-42. PMID 17983841
12. U.S. Food and Drug Administration. Summary of Safety and Effectiveness Data: Cervical-Stim Model 505L Cervical Fusion System. 2004; https://www.accessdata.fda.gov/cdrh_docs/pdf3/P030034b.pdf. Accessed March 10, 2023.
13. Coric D, Bullard DE, Patel VV, et al. Pulsed electromagnetic field stimulation may improve fusion rates in cervical arthrodesis in high-risk populations. Bone Joint Res. Feb 2018; 7(2): 124-130. PMID 29437635
14. North American Spine Society (NASS). NASS Coverage Policy Recommendations: Electrical Stimulation for Bone Healing. 2016; https://www.spine.org/PolicyPractice/CoverageRecommendations/AboutCoverageRecommendations.aspx. Accessed March 10, 2023.
15. Kaiser MG, Eck JC, Groff MW, et al. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 17: bone growth stimulators as an adjunct for lumbar fusion. J Neurosurg Spine. Jul 2014; 21(1): 133-9. PMID 24980594
16. Resnick DK, Choudhri TF, Dailey AT, et al. Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 17: bone growth stimulators and lumbar fusion. J Neurosurg Spine. Jun 2005; 2(6): 737-40. PMID 16028745
17. Centers for Medicare & Medicaid Services. National Coverage Determination for Osteogenic Stimulators (150.2). 2005; https://www.cms.gov/medicare-coverage-database/details/ncd-details.aspx?NCDId=65&ncdver=2&DocID=150.2. 

Coding Section 

Codes	Number	Description
CPT	20974	Electrical stimulation to aid bone healing; noninvasive (non-operative)
	20975	invasive (operative)
HCPCS	E0748	Osteogenesis stimulator, electrical, non-invasive, spinal applications
	E0749	Osteogenesis stimulator, electrical (surgically implanted)
ICD-10-CM	M43.12-M43.13; M43.15-M43.17	Spondylolisthesis cervical and lumbar region code range
	M48.02-M48.03; M48.05-M48.07	Spinal stenosis cervical and lumbar region code range
	M51.04-M51.9	Thoracic, thoracolumbar, and lumbosacral intervertebral disc disorders code range
	M51.A0-M51.A5	Intervertebral annulus fibrosus defect code range (eff 10/01/2022)
ICD-10-PCS		ICD-10-PCS codes are only used for inpatient services. There is no specific ICD-10-PCS code for this procedure.
	00HU0MZ, 00HU3MZ,00HU4MZ	Surgical, central nervous system, insertion, spinal canal, neurostimulator lead, code by approach
	00HV0MZ, 00HV3MZ, 00HV4MZ	Surgical, central nervous system, insertion, spinal cord, neurostimulator lead, code by approach
	00WU0MZ, 00WU3MZ, 00WU4MZ	Surgical, central nervous system, removal, spinal canal, neurostimulator lead, code by approach
	00PV0MZ, 00PV3MZ, 00PV4MZ	Surgical, central nervous system, removal, spinal cord, neurostimulator lead, code by approach
	00WU0MZ, 00WU3MZ, 00WU4MZ	Surgical, central nervous system, revision, spinal canal, neurostimulator lead, code by approach
	00WV0MZ, 00WV3MZ, 00WV4MZ	Surgical, central nervous system, revision, spinal cord, neurostimulator lead, code by approach
Type of service	Surgical
Place of service	Outpatient/Inpatient

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.  

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

"Current Procedural Terminology © American Medical Association. All Rights Reserved" 

History From 2024 Forward     

01012024  NEW POLICY

05/17/2024 Annual review, no change to policy intent.