Spine fusion for discogenic low back pain: outcomes in patients treated with or without pulsed electromagnetic field stimulation

Effect of electrical stimulation on the fusion rate after spinal surgery: a systematic review and meta-analysis

Electrical stimulation is an important adjuvant therapy for spinal surgery, but whether receiving electrical stimulation can improve the fusion rate after spinal surgery is still controversial. The purpose of this study was to analyse and evaluate the effect of electrical stimulation on the fusion rate after spinal surgery. We systematically searched for related articles published in the PubMed, Embase and Cochrane Library databases on or before September 30, 2023. The odds ratio (OR) with 95% confidence interval (CI) and the fusion rates of the experimental group and the control group were calculated by a random-effects meta-analysis model. The analysis showed that receiving electrical stimulation significantly increased the probability of successful spinal fusion (OR 2.66 [95% CI 1.79-3.97]), and the average fusion rate of the electrical stimulation group (86.8%) was significantly greater than that of the control group (73.7%). The fusion rate in the direct current (DC) stimulation group was 2.33 times greater than that in the control group (OR 2.33 [95% CI 1.37-3.96]), and that in the pulsed electromagnetic field (PEMF) group was 2.60 times greater than that in the control group (OR 2.60 [95% CI 1.29-5.27]). Similarly, the fusion rate in the capacitive coupling (CC) electrical stimulation group was 3.44 times greater than that in the control group (OR 3.44 [95% CI 1.75-6.75]), indicating that regardless of the type of electrical stimulation, the fusion rate after spinal surgery improved to a certain extent. Electrical stimulation as an adjuvant therapy seems to improve the fusion rate after spinal surgery to a certain extent, but the specific effectiveness of this therapy needs to be further studied.

Adjunctive Use of Bone Growth Stimulation Increases Cervical Spine Fusion Rates in Patients at Risk for Pseudarthrosis

STUDY DESIGN

A prospective multicenter clinical trial (NCT03177473) was conducted with a retrospective cohort used as a control arm.

OBJECTIVE

The purpose of this study was to evaluate cervical spine fusion rates in subjects with risk factors for pseudarthrosis who received pulsed electromagnetic field (PEMF) treatment.

SUMMARY OF BACKGROUND DATA

Certain risk factors predispose patients to pseudarthrosis, which is associated with prolonged pain, reduced function, and decreased quality of life.

METHODS

Subjects in the PEMF group were treated with PEMF for 6 months postoperatively. The primary outcome measure was fusion status at the 12-month follow-up period. Fusion status was determined using anterior/posterior, lateral, and flexion/extension radiographs and computed tomography (without contrast).

RESULTS

A total of 213 patients were evaluated (PEMF, n=160; Control, n=53). At baseline, the PEMF group had a higher percentage of subjects who used nicotine ( P =0.01), had osteoporosis ( P <0.05), multi-level disease ( P <0.0001), and were >65 years of age ( P =0.01). The PEMF group showed over two-fold higher percentage of subjects that had ≥3 risk factors (n=92/160, 57.5%) compared with the control group (n=14/53, 26.4%). At the 12-month follow-up, the PEMF group demonstrated significantly higher fusion rates compared with the control (90.0% vs. 60.4%, P <0.05). A statistically significant improvement in fusion rate was observed in PEMF subjects with multi-level surgery ( P <0.0001) and high BMI (>30 kg/m 2 ; P =0.0021) when compared with the control group. No significant safety concerns were observed.

CONCLUSIONS

Adjunctive use of PEMF stimulation provides significant improvements in cervical spine fusion rates in subjects having risk factors for pseudarthrosis. When compared with control subjects that did not use PEMF stimulation, treated subjects showed improved fusion outcomes despite being older, having more risk factors for pseudarthrosis, and undergoing more complex surgeries.

Noninvasive electrical stimulation as an adjunct to fusion procedures: a systematic review and meta-analysis

OBJECTIVE

Noninvasive electrical stimulation represents a distinct group of devices used to augment fusion rates. However, data regarding outcomes of noninvasive electrical stimulation have come from a small number of studies. The goal of this systematic review and meta-analysis was to determine outcomes of noninvasive electrical stimulation used as an adjunct to fusion procedures to improve rates of successful fusion.

METHODS

PubMed, Embase, and the Cochrane Clinical Trials database were searched according to search strategy and PRISMA guidelines. Random-effects meta-analyses of fusion rates with the three main modalities of noninvasive electrical stimulation, capacitively coupled stimulation (CCS), pulsed electromagnetic fields (PEMFs), and combined magnetic fields (CMFs), were conducted using R version 4.1.0 (The R Foundation for Statistical Computing). Both retrospective studies and clinical trials were included. Animal studies were excluded. Risk-of-bias analysis was performed with the Risk of Bias 2 (RoB 2) and Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tools.

RESULTS

Searches of PubMed, Embase, and the Cochrane Clinical Trials database identified 8 articles with 1216 participants meeting criteria from 213 initial results. There was a high overall risk of bias identified for the majority of randomized studies. No meta-analysis could be performed for CCS as only 1 study was identified. Meta-analysis of 6 studies of fusion rates in PEMF did not find any difference between treatment and control groups (OR 1.89, 95% CI 0.36-9.80, p = 0.449). Meta-analysis of 2 studies of CMF found no difference in fusion rates between control and treatment groups (OR 0.90, 95% CI 0.07-11.93, p = 0.939). Subgroup analysis of PEMF was limited given the small number of studies and patients, although significantly increased fusion rates were seen in some subgroups.

CONCLUSIONS

This meta-analysis of clinical outcomes and fusion rates in noninvasive electrical stimulation compared to no stimulation did not identify any increases in fusion rates for any modality. A high degree of heterogeneity between studies was noted. Although subgroup analysis identified significant differences in fusion rates in certain groups, these findings were based on a small number of studies and further research is needed. This analysis does not support routine use of these devices to augment fusion rates, although the data are limited by a high risk of bias and a small number of available studies.

Pulsed Electromagnetic Field Stimulators Efficacy for Noninvasive Bone Growth in Spine Surgery

The growth of pulsed electromagnetic field (PEMF) therapy and its progress over the years for use in post-operative bone growth has been revolutionary in its effect on bone tissue proliferation and vascular flow. However, further progress in PEMF therapy has been difficult due to lack of more evidence-based understanding of its mechanism of action. Our objective was to review the current understanding of bone growth physiology, the mechanism of PEMF therapy action along with its application in spinal surgery and associated outcomes. The authors of this review examined multiple controlled, comparative, and cohort studies to compare fusion rates of patients undergoing PEMF stimulation. Examining spinal fusion rates, a rounded comparison of post-fusion outcomes with and without bone stimulator was performed. Results showed that postoperative spinal surgery PEMF stimulation had higher rates of fusion than control groups. Though PEMF therapy was proven more effective, multiple factors contributed to difficulty in patient compliance for use. Extended timeframe of treatment and cost of treatment were the main obstacles to full compliance. This review showed that PEMF therapy presented an increased rate of recovery in patients, supporting the use of these devices as an effective post-surgical aid. Given the recent advances in the development of PEMF devices, affordability and access will be much easier suited to the patient population, allowing for more readily available treatment options.

Does Capacitively Coupled Electric Fields Stimulation Improve Clinical Outcomes After Instrumented Spinal Fusion? A Multicentered Randomized, Prospective, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Lumbar spinal fusion (LSF) is used to treat lumbar degenerative disorders. Methods to improve the functional recovery of patients undergoing LSF is one of the main goals in daily clinical practice. The objective of this study is to assess whether biophysical stimulation with capacitively coupled electric fields (CCEF) can be used as adjuvant therapy to enhance clinical outcome in LSF-treated patients.

METHODS

Forty-two patients undergoing LSF were assessed and randomly allocated to either the active or to the placebo group. Follow-up visits were performed at 1, 3, 6, and 12 months after surgery; long-term follow-up was performed at year 10. Visual analogue scale (VAS), the Oswestry Disability Index (ODI), and the 36-item Short Form Health Survey (SF-36) questionnaire were recorded.

RESULTS

This study demonstrates a significant improvement in CCEF-treated patients at 6 and 12 months' follow-up for SF-36, and at 12 months' follow-up for ODI values. Based on SF-36 and ODI scores, we reported a significantly higher percentage of successful treatments at 12 months in the active compared with the placebo group. Moreover, in a subset of patients at 10 years' follow-up, a significant difference was reported in VAS and ODI scores between groups.

CONCLUSIONS

The results demonstrate that 3 months of CCEF treatment immediately after surgery is effective in reducing ODI and improving SF-36 score, and that these benefits can be maintained up to 12 months. In a subset of patients, these positive outcomes are retained up to 10 years.

LEVEL OF EVIDENCE

I.

CLINICAL RELEVANCE

This study suggests that CCEF stimulation can be used as an adjunct to LSF for spine diseases, for increasing overall quality of life and improving patients' functional recovery. CCEF is safe and well tolerated, compatible with activities of daily living.

Combined magnetic field results in higher fusion rates than pulsed electromagnetic field bone stimulation after thoracolumbar fusion surgery

BACKGROUND

Bone growth stimulators have been used as an adjunct to spinal fusion surgery in efforts to increase fusion rates.

METHODS

The authors retrospectively reviewed the medical records of patients who underwent thoracolumbar fusion surgeries by a single surgeon. Patients were then separated into three groups; pulsed electromagnetic field stimulation (PEMF), combined magnetic field stimulation (CMF) or no stimulation (NS), and computed tomography radiographic results at least 1 year after surgery were compared (solid fusion, stable nonunion, and pseudarthrosis).

RESULTS

A total of 60 patients were included; 16 (26.7%) used PEMF, 24 (40.0%) used CMF, and 20 (33.3%) had NS. There were no significant differences in patient demographics. There was no difference in the mean fusion levels (p = 0. 477). Solid fusion was achieved in 11/16 (68.8%) PEMF, 21/24 (87.5%) CMF, and 20/20 (100.0%) NS patients. Stable nonunion was displayed in 2/24 (8.3%) CMF, and zero PEMF and NS patients. There were 5/16 (31.3%) PEMF, 1/24 (4.2%) CMF, and zero NS patients demonstrating radiologic pseudarthrosis. There was a statistically significant difference between PEMF and CMF (p = 0.017) and between PEMF and NS (p = 0.006) groups. No statistical difference was found between CMF and NS (p = 1.000).

CONCLUSION

This is the first study to compare PEMF and CMF bone growth stimulators in patients with degenerative pathologies who underwent thoracolumbar spinal fusions. Overall, the addition of these bone growth stimulators does not improve fusion outcomes, although CMF appears superior to PEMF.

The effect of electrical stimulation therapies on spinal fusion: a cross-disciplinary systematic review and meta-analysis of the preclinical and clinical data

OBJECTIVE

Nonunion is a common complication of spinal fusion surgeries. Electrical stimulation technologies (ESTs)-namely, direct current stimulation (DCS), capacitive coupling stimulation (CCS), and inductive coupling stimulation (ICS)-have been suggested to improve fusion rates. However, the evidence to support their use is based solely on small trials. Here, the authors report the results of meta-analyses of the preclinical and clinical data from the literature to provide estimates of the overall effect of these therapies at large and in subgroups.

METHODS

A systematic review of the English-language literature was performed using PubMed, Embase, and Web of Science databases. The query of these databases was designed to include all preclinical and clinical studies examining ESTs for spinal fusion. The primary endpoint was the fusion rate at the last follow-up. Meta-analyses were performed using a Freeman-Tukey double arcsine transformation followed by random-effects modeling.

RESULTS

A total of 33 articles (17 preclinical, 16 clinical) were identified, of which 11 preclinical studies (257 animals) and 13 clinical studies (2144 patients) were included in the meta-analysis. Among preclinical studies, the mean fusion rates were higher among EST-treated animals (OR 4.79, p < 0.001). Clinical studies similarly showed ESTs to increase fusion rates (OR 2.26, p < 0.001). Of EST modalities, only DCS improved fusion rates in both preclinical (OR 5.64, p < 0.001) and clinical (OR 2.13, p = 0.03) populations; ICS improved fusion in clinical studies only (OR 2.45, p = 0.014). CCS was not effective at increasing fusion, although only one clinical study was identified. A subanalysis of the clinical studies found that ESTs increased fusion rates in the following populations: patients with difficult-to-fuse spines, those who smoke, and those who underwent multilevel fusions.

CONCLUSIONS

The authors found that electrical stimulation devices may produce clinically significant increases in arthrodesis rates among patients undergoing spinal fusion. They also found that the pro-arthrodesis effects seen in preclinical studies are also found in clinical populations, suggesting that findings in animal studies are translatable. Additional research is needed to analyze the cost-effectiveness of these devices.

Electrical stimulation-based bone fracture treatment, if it works so well why do not more surgeons use it?

BACKGROUND

Electrical stimulation (EStim) has been proven to promote bone healing in experimental settings and has been used clinically for many years and yet it has not become a mainstream clinical treatment.

METHODS

To better understand this discrepancy we reviewed 72 animal and 69 clinical studies published between 1978 and 2017, and separately asked 161 orthopedic surgeons worldwide about their awareness, experience, and acceptance of EStim for treating fracture patients.

RESULTS

Of the 72 animal studies, 77% reported positive outcomes, and the most common model, bone, fracture type, and method of administering EStim were dog, tibia, large bone defects, and DC, respectively. Of the 69 clinical studies, 73% reported positive outcomes, and the most common bone treated, fracture type, and method of administration were tibia, delayed/non-unions, and PEMF, respectively. Of the 161 survey respondents, most (73%) were aware of the positive outcomes reported in the literature, yet only 32% used EStim in their patients. The most common fracture they treated was delayed/non-unions, and the greatest problems with EStim were high costs and inconsistent results.

CONCLUSION

Despite their awareness of EStim's pro-fracture healing effects few orthopedic surgeons use it in their patients. Our review of the literature and survey indicate that this is due to confusion in the literature due to the great variation in methods reported, and the inconsistent results associated with this treatment approach. In spite of this surgeons seem to be open to using this treatment if advancements in the technology were able to provide an easy to use, cost-effective method to deliver EStim in their fracture patients.

Electrical Stimulation and Bone Healing: A Review of Current Technology and Clinical Applications

Pseudarthrosis is an exceedingly common, costly, and morbid complication in the treatment of long bone fractures and after spinal fusion surgery. Electrical bone growth stimulation (EBGS) presents a unique approach to accelerate healing and promote fusion success rates. Over the past three decades, increased experience and widespread use of EBGS devices has led to significant improvements in stimulation paradigms and clinical outcomes. In this paper, we comprehensively review the literature and examine the history, scientific evidence, available technology, and clinical applications for EBGS. We summarize indications, limitations, and provide an overview of cost-effectiveness and future directions of EBGS technology. Various models of electrical stimulation have been proposed and marketed as adjuncts for spinal fusions and long bone fractures. Clinical studies show variable safety and efficacy of EBGS under different conditions and clinical scenarios. While the results of clinical trials do not support indiscriminate EBGS utilization for any bone injury, the evidence does suggest that EBGS is desirable and cost efficient for certain orthopedic indications, especially when used in combination with standard, first-line treatments. This review should serve as a reference to inform practicing clinicians of available treatment options, facilitate evidence-based decision making, and provide a platform for further research.

EFFECT OF PULSED ELECTROMAGNETIC FIELD ON THE CONSOLIDATION OF POSTEROLATERAL ARTHRODESES IN THE LUMBOSACRAL SPINE: A PROSPECTIVE, DOUBLE-BLIND, RANDOMIZED STUDY

ABSTRACT Objective: To assess the effect of pulsed electromagnetic field (PEMF) on the consolidation of instrumented lumbar posterolateral arthrodeses in patients who have been surgically treated for degenerative spine disease. Methods: Forty cases were recruited from 163 consecutive patients undergoing lumbar arthrodesis at the same center. The patients were randomized into two groups of 20 patients: Active Group, who were exposed to PEMF for 4 hours a day for 90 days after surgery, and Inactive Group, who received an identical device, with the same instructions for use but without the ability to generate PEMF. The patients underwent computed tomography scans at 45, 90, 180 and 360 days after surgery to check for the occurrence of arthrodesis at each operated spinal level. Results: In the course of the study, two patients were excluded from each group. There were no significant differences between the groups with respect to age, gender, smoking habit, or the number of vertebral levels included in the arthrodesis. The percentage of consolidation of the vertebral levels increased at 90, 180 and 360 days compared to 45 days (p<0.001) in both groups. The Active Group had a 276% greater chance of consolidation in the vertebral levels (OR = 3.76; 95% CI: 1.39-10.20), regardless of the time of evaluation. Patients in the Active Group presented 16% more consolidation than patients in the inactive group (p=0.018). Conclusions: Post-operative exposure to PEMF following instrumented arthrodesis of the lumbar spine for degenerative spine disease increased consolidation in the first year after surgery.

Pulsed Electromagnetic Fields Enhance Bone Morphogenetic Protein-2 Dependent-Bone Regeneration

The use of recombinant human bone morphogenetic protein-2 (rhBMP-2) for the purpose of promoting bone regeneration is emerging; however, the high dose of rhBMP-2 required in humans is accompanied by several limitations, including bone resorption and swelling. To reduce the dose of rhBMP-2 required, the applicability of pulsed electromagnetic fields (PEMF) was evaluated using a rat calvarial defect model. After creating an 8-mm-diameter calvarial bone defect, a collagen sponge soaked in different concentrations (0, 2.5, 5, 10 μg) of rhBMP-2 was implanted at the defect area. One week after surgery, PEMF was applied for 8 h/day over 5 days in an experimental group of animals (n = 28) using a width of 12 μs, a pulse frequency of 60 Hz, and a magnetic intensity of 10 G. Animals were sacrificed 4 weeks after surgery and assessed by microcomputed tomography and histological and immunohistochemical analyses. In the absence of application of PEMF, bone volume, bone mineral density, trabecular thickness, trabecular number, and trabecular separation, all showed statistically significant differences, depending on the concentration of rhBMP-2 utilized (p < 0.001). PEMF accelerated bone regeneration in the groups that received 0, 2.5, and 5 μg rhBMP-2 (p < 0.05). In contrast, administration of 10 μg rhBMP-2 resulted in no additive effect on bone regeneration in combination with PEMF. Groups receiving no rhBMP-2 showed distinct bone regeneration in the central zone of the bone defect when treated with PEMF, whereas they failed to bridge the defect space without PEMF. Among the groups without PEMF, soft tissue infiltrations from the outer surface on the skin side were common. Among groups with PEMF, the groups receiving 5 and 10 μg rhBMP-2 displayed denser bone with significantly reduced dead spaces. The application of PEMF did not result in an accelerated effect on bone regeneration in groups treated with 10 μg rhBMP-2. Therefore, our data demonstrate that PEMF can promote bone regeneration in animals treated with a low concentration of rhBMP-2.

Efficacy of electrical stimulation for spinal fusion: a meta-analysis of fusion rate

BACKGROUND CONTEXT

Many clinical studies have demonstrated the effectiveness of electrical stimulation as an adjunct to spinal arthrodesis. However, there is a paucity of comparative data among different electrical stimulation techniques.

PURPOSE

To compare the efficacy of three electrical stimulation methods for spinal fusion based on the literature review.

SAMPLE

Twenty-one articles, meeting all the inclusion criteria, were selected. A total of 1,381 patients were evaluated.

STUDY DESIGN

Systematic literature review and meta-analysis.

OUTCOME MEASURES

Fusion rates were determined using radiography or computed tomography.

METHODS

A systematic literature review was conducted on spinal fusion surgeries with the aid of electrical stimulation devices. Only studies applying radiography or computed tomography for fusion assessment were included. Study groups were divided based on electrical stimulation types and were further grouped by other patient characteristics. Pooled estimates and 95% confidence intervals (CIs) were calculated by random-effects meta-analysis.

RESULTS

The pooled fusion rate for all studies was 85% (95% CI, 79-90). There were 14 direct current, 1 capacitive coupling (CC), and 10 inductive coupling studies in our analysis, with combined fusion rate of 85% (95% CI, 76-91), 90% (95% CI, 83-95), and 85% (95% CI, 74-93), respectively. There were no statistically significant differences among the three electrical stimulation methods. Further subgroup analysis suggested that age, sex, smoking status, surgery type, fusion levels, fusion column, implant use, and graft type did not significantly influence the fusion rate.

CONCLUSIONS

The three types of electrical stimulation devices had similar clinical efficacy in promoting bone growth for spinal fusion. The results for CC stimulation should be applied with caution as only one relevant study was identified.

Evaluation of pulsed electromagnetic field therapy in the management of patients with discogenic lumbar radiculopathy

AIM

This randomized clinical trial was designed to evaluate the effect of pulsed electromagnetic field therapy (PEMF) in the management of patients with discogenic lumbar radiculopathy.

METHODS

Forty patients suffering from lumbar radiculopathy due to lumbar disc prolapse were randomly assigned to one of two groups: a study group that included 20 patients who received PEMF therapy and a control group that included 20 patients who received placebo treatment. Both groups were evaluated at bases line and after 3 weeks by using a visual analogue scale (VAS) (0-10), somatosensory evoked potentials (SSEPs) for selected dermatomes and Modified Oswestry Low Back Pain Disability Questionnaire (OSW), and findings were compared before and after treatment.

RESULTS

Significant differences were observed between both groups before and after application of PEMF therapy relative to VAS (P=0.024), total OSW (P<0.001), and other domains of OSW score (pain intensity [P=0.009], personal care [P=0.01], lifting [P<0.001], walking [P<0.001], sitting [P<0.001], standing [P<0.001], sleeping [P<0.001], social life [P<0.001] and employment [P=0.003]). Other significant differences were observed between both groups relative to SSEP latency and amplitude of the evaluated dermatomes on the right side (P=0.022 and P=0.001, respectively), and left side latency and amplitude (P=0.016 and P=0.002, respectively).

CONCLUSION

PEMF therapy is an effective method for the conservative treatment of lumbar radiculopathy caused by lumbar disc prolapse. In addition to improvement of clinically observed radicular symptoms, PEMF also seems effective in reducing nerve root compression as evidenced by improvement of SSEP parameters after treatment.

Novel effect of biphasic electric current on in vitro osteogenesis and cytokine production in human mesenchymal stromal cells

Electrical stimulation (ES) can activate diverse biostimulatory responses in a range of tissues. Of various forms of ES, the application of biphasic electric current (BEC) is a new approach to bone formation. This study is to investigate the effects and mechanism of action of BEC in osteoblast differentiation and cytokine production in human mesenchymal stromal cells (hMSCs). Using an in vitro culture system with a modified version of the BEC stimulator chip used in our previous study, we exposed hMSCs to a 100 Hz ES with a magnitude of 1.5/15 muA/cm(2) for 250/25 mus. hMSCs showed increased proliferation during static BEC stimulation for 5 days. However, alkaline phosphatase activity and calcium deposition were enhanced in hMSCs 7 days after the stimulation, rather than during the period of ES. BEC induced vascular endothelial growth factor (VEGF) and BMP-2 production; the former can enhance the proliferation of human umbilical vein endothelial cells in culture using conditioned media from BEC cultures. Treatment with selective inhibitors of p38 MAPK (SB203580) or Erk (PD98059), as well as calcium channel blockers (verapamil and nifedipine), reduced the BEC-mediated increase of VEGF expression and cell proliferation. These findings reveal that BEC is involved in the osteoblast differentiation of hMSCs through enhancement of cell proliferation and modulation of the local endocrine environment through VEGF and BMP-2 induction through the activation of MAPK (Erk and p38) and the calcium channel. Thus, local stimulation using BEC might be most beneficial in promoting osteogenic differentiation of hMSCs, resulting in enhanced bone formation for bone tissue engineering.

Electrical stimulation therapies for spinal fusions: current concepts

Electrical stimulation therapies have been used for more than 30 years to enhance spinal fusions. Although their positive effects on spinal fusions have been widely reported, the mechanisms of action of the technologies were only recently identified. Three types of technologies are available clinically: direct current, capacitive coupling, and inductive coupling. The latter is the basis of pulsed electromagnetic fields and combined magnetic fields. This review summarizes the current concepts on the mechanisms of action, animal and clinical studies, and cost justification for the use of electrical stimulation for spinal fusions. Scientific studies support the validity of electrical stimulation treatments. The mechanisms of action of each of the three electrical stimulation therapies are different. New data demonstrates that the upregulation of several growth factors may be responsible for the clinical success seen with the use of such technologies.

Electric stimulation and hyperbaric oxygen therapy in the treatment of nonunions

Up to 10% of the fractures occurring annually in the U.S. end up in non-union or delayed union. Classical treatment with osteosynthesis and bone grafting is not always successful. Alternatives in treatment have long ago been considered. This article presents current concepts in treatment with electrical stimulation and hyperbaric oxygen, the mechanisms of action, experimental and clinical evidence of their application.

Pulsed electromagnetic field therapy and osteoarthritis of the knee: Synthesis of the literature

Knee joint osteoarthritis is a painful disorder, often resulting in progressive functional impairment and disability. One modality used in the treatment of knee osteoarthritis is pulsed electromagnetic field therapy. This article examines the evidence base that details the rationale for and the outcomes of applying pulsed electromagnetic fields to the osteoarthritic knee joint.

The related English language literature was reviewed to examine whether pulsed electromagnetic fields applied to an osteoarthritic knee joint are likely to be efficacious, and if so why. Although limitations to the published literature on this topic exist, the available basic and seven randomized clinical research studies in this field support the value of continuing to explore the potential of applying pulsed electromagnetic fields to ameliorate pain and dysfunction associated with the osteoarthritic knee joint.

Further clinical research to validate the use of pulsed electromagnetic fields in lessening osteoarthritic knee joint pain and facilitating function and joint repair is indicated.

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 17: bone growth stimulators and lumbar fusion

There have been a number of randomized studies supporting the use of ES for the promotion of bone healing following lumbar fusion. All of the published studies have methodological flaws that prevent the studies from providing Class I medical evidence. There is, however, Class II and III evidence to support the use of direct current stimulation or CCS 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 PEMFS for enhancing fusion rates following PLE Class II and III medical evidence supports the use of PEMFS 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.

Bone mass is preserved in a critical-sized osteotomy by low energy pulsed electromagnetic fields as quantitated by in vivo micro-computed tomography

The effectiveness of non-invasive pulsed electromagnetic fields (PEMF) on stimulating bone formation in vivo to augment fracture healing is still controversial, largely because of technical ambiguities in data interpretation within several previous studies. To address this uncertainty, we implemented a rigorously controlled, blinded protocol using a bilateral, mid-diaphyseal fibular osteotomy model in aged rats that achieved a non-union status within 3-4 weeks post-surgery. Bilateral osteotomies allowed delivery of a PEMF treatment protocol on one hind limb, with the contralateral limb representing a within-animal sham-treatment. Bone volumes in both PEMF-treated and sham-treated fibulae were assessed simultaneously in vivo using highly sensitive, high-resolution micro-computed tomography (microCT) over the course of treatment. We found a significant reduction in the amount of time-dependent bone volume loss in PEMF-treated, distal fibular segments as compared to their contralateral sham-treated bones. Osteotomy gap size was significantly smaller in hind limbs exposed to PEMF over sham-treatment. Therefore, our data demonstrate measurable biological consequences of PEMF exposure on in vivo bone tissue.

Reversal of Delayed Union of Anterior Cervical Fusion Treated with Pulsed Electromagnetic Field Stimulation: Case Report

We present a case report of anterior cervical fusion non-union that was successfully treated with pulsed electromagnetic field (PEMF) stimulation. In this case, a C6-C7 nonunion was identified clinically and radiographically 1 year after surgery. Imaging revealed nonunion with partial resorption of the bone graft compared with imaging studies performed 8 months earlier. The patient wore a PEMF stimulation device for 3 h/d for 10 months. After 3 months of treatment, the patient's symptoms were resolved. X-rays obtained after 15 weeks of stimulation showed improvement in bone fusion, and x-rays obtained at 31 weeks after stimulation showed even bone density around the C7 screws. The patient remained symptom-free 13 months after the termination of PEMF stimulation at last assessment. PEMF stimulation demonstrated its clinical potential in healing established nonunion of anterior cervical spine fusion. Its use is noninvasive and can be considered an alternative to surgical intervention in selected patients.

A multicenter clinical trial on the use of pulsed electromagnetic fields in the treatment of temporomandibular disorders

STATEMENT OF THE PROBLEM

Pulsed electromagnetic fields have shown therapeutic benefit in the treatment of numerous forms of osteoarthritis but have not been evaluated for their effects on the temporomandibular joint (TMJ).

PURPOSE

The aim of this study was to examine the effects of pulsed electromagnetic fields in the treatment of patients with temporomandibular disorders (TMD).

MATERIALS AND METHODS

A multicenter clinical trial compared active treatment of 36 patients using pulsed electromagnetic fields to placebo treatment of 42 patients with TMD with pain in 1 or both TMJs and/or limited opening of less than 40 mm. Subjective parameters including pain intensity, pain frequency, degree of limitation, restriction of daily life, and intensity and frequency of joint noises were evaluated using a visual analog scale. Trained, blinded examiners assessed the clinical parameters according to Research Diagnostic Criteria for temporomandibular disorders before treatment (baseline), directly after nine 1-hour treatments on consecutive working days, 6 weeks after treatment, and 4 months after treatment. Statistical evaluation was done using the Friedman test, and by paired comparison between baseline and follow-up examinations using the U test (P < .05).

RESULTS

Seventy-six patients completed the study. For both the active and placebo treatment, significant improvements were seen in the subjective data (P < .01). Patients with anterior disk displacement without reduction also showed significant improvements in active mouth opening (P = .015), patients with ostheoarthritis only showed improvements in some of the subjective parameters (P < .03), and patients with anterior disk displacement with reduction showed no improvement at all.

CONCLUSIONS

Pulsed electromagnetic fields had no specific treatment effects in patients with temporomandibular disorders.

Agents physiques antalgiques

Analgesic electrotherapy is now based on more consistent scientific data; the biological action of the electric current, of the electromagnetic radiations and of the mechanical vibrations is better approached. But the randomized control trials still provide contradictory results concerning the analgesic efficiency of the cryotherapy, the TENS, the pulsed electro-magnetic fields, the ultrasound and laser therapy, the shock waves; iontophoresis, short waves, microwaves, infrasound vibrations are very few investigated. The analgesic electrotherapy cannot be recommended nor prohibited; physical agents represent only therapeutic options. On the basis of the scientific data and of their personal experience, the therapists can use them. More controlled clinical investigations of higher methodological levels are still required.

Use of physical forces in bone healing

During the past two decades, a number of physical modalities have been approved for the management of nonunions and delayed unions. Implantable direct current stimulation is effective in managing established nonunions of the extremities and as an adjuvant in achieving spinal fusion. Pulsed electromagnetic fields and capacitive coupling induce fields through the soft tissue, resulting in low-magnitude voltage and currents at the fracture site. Pulsed electromagnetic fields may be as effective as surgery in managing extremity nonunions. Capacitive coupling appears to be effective both in extremity nonunions and lumbar fusions. Low-intensity ultrasound has been used to speed normal fracture healing and manage delayed unions. It has recently been approved for the management of nonunions. Despite the different mechanisms for stimulating bone healing, all signals result in increased intracellular calcium, thereby leading to bone formation.

The use of electrical stimulation to enhance spinal fusion

The goal of spinal arthrodesis is a solid osseous union across one or more spinal segments. A solid bone union after arthrodesis is commonly known as a spinal fusion. Surgeons have begun to understand the biomechanical and biological factors that influence the bone-healing process. One of the most commonly used adjuncts is spinal instrumentation. Instrumentation has increased the spinal fusion rate; however, fusion failure (that is, nonunion or pseudarthrosis) remains significant. A less commonly used adjunct is electrical stimulation (ES). Investigators in experimental studies have demonstrated the beneficial effects of ES on increasing the fusion rate. In this review the authors discuss the evidence concerning the benefits of ES as an adjunct to spinal arthrodesis. In addition, the different types of ES devices are described along with the current experimental and clinical evidence for each type of device.