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Magnetic Therapy Research: Bone Fractures

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General


Bone Formation


Fracture Healing

Non-Union Fracture Healing


Pseudoarthrosis (formation of false joint)


Spinal Fusion


Osteonecrosis (death of bone cells)


Augmented bone-matrix formation and osteogenesis under magnetic field stimulation in vivo XRD, TEM and SEM investigations.

Singh P, YashRoy RC, Hoque M. Biophysics and Electron Microscopy Section, Indian Veterinary Research Institute, Izatnagar-243122, UP, India. psingh67@yahoo.com

Bone is a composite biomaterial, which is formed, when proteins constituting collagen fibers attract calcium, phosphate and hydroxide ions in solution to nucleate atop the fibers. It grows into a hard structure of tiny crystallites of hydroxyapatite, aligned along the long axis of collagen fibers. The present work reports the stimulating effect of static magnetic field on microstructure and mineralization process of bone repair. A unilateral transverse fracture of mid-shaft of metacarpal was surgically created in healthy goats under thiopental sedation and xylocaine analgesia. Two bar magnets (approximately 800 gauss/cm2 field strength) were placed across the fracture line at opposite pole alignment immobilized in Plaster of Paris (POP) splint bandage for static magnetic field stimulation. Radiographs were taken at weekly intervals up to 45 days. Results show that formation of extra-cellular matrix and its microstructure can be influenced by non-invasive physical stimulus (magnetic field) for achieving an enhanced osteogenesis, leading to quicker regeneration of bone tissue in goats. X-ray diffraction (XRD) patterns of treated (magnetic field-exposed) and control samples revealed the presence and orientation of crystalline structures. Intensity of diffraction peaks corresponding to 310 and 222 planes were enhanced with respect to 211 families of reflections, indicating preferential alignment of the crystals. Also, the percent crystallinity and crystal size were increased in treated samples. The study provides a biophysical basis for augmented fracture healing under the influence of semi-aligned static magnetic field applied across the fracture line.

PMID: 16967906 [PubMed - indexed for MEDLINE]

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Fundamental and practical aspects of therapeutic uses of pulsed electromagnetic fields (PEMFs).

Bassett CA.

Department of Orthopedic Surgery, Columbia University, New York, New York.

The beneficial therapeutic effects of selected low-energy, time-varying magnetic fields, called PEMFs, have been documented with increasing frequency since 1973. Initially, this form of athermal energy was used mainly as a salvage for patients with long-standing juvenile and adult nonunions. Many of these individuals were candidates for amputation. Their clearly documented resistance to the usual forms of surgical treatment, including bone grafting, served as a reasonable control in judging the efficacy of this new therapeutic method, particularly when PEMFs were the sole change in patient management. More recently, the biological effectiveness of this approach in augmenting bone healing has been confirmed by several highly significant double-blind and controlled prospective studies in less challenging clinical circumstances. Furthermore, double-blind evidence of therapeutic effects in other clinical disorders has emerged. These data, coupled with well-controlled laboratory findings on pertinent mechanisms of action, have begun to place PEMFs on a therapeutic par with surgically invasive methods but at considerably less risk and cost. As a result of these clinical observations and concerns about electromagnetic "pollution", interactions of nonionizing electromagnetic fields with biological processes have been the subject of increasing investigational activity. Over the past decade, the number of publications on these topics has risen exponentially. They now include textbooks, speciality journals, regular reviews by government agencies, in addition to individual articles, appearing in the wide spectrum of peer-reviewed, scientific sources. In a recent editorial in Current Contents, the editor reviews the frontiers of biomedical engineering focusing on Science Citation Index methods for identifying core research endeavors. Dr. Garfield chose PEMFs from among other biomedical engineering efforts as an example of a rapidly emerging discipline. Three new societies in the bioelectromagnetics, bioelectrochemistry, and bioelectrical growth and repair have been organized during this time, along with a number of national and international committees and conferences. These activities augment a continuing interest by the IEEE in the U.S. and the IEE in the U.K. This review focuses on the principles and practice behind the therapeutic use of "PEMFs". This term is restricted to time-varying magnetic field characteristics that induce voltage waveform patterns in bone similar to those resulting from mechanical deformation. These asymmetric, broad-band pulses affect a number of biologic processes athermally. Many of these processes appear to have the ability to modify selected pathologic states in the musculoskeletal and other systems.

Crit Rev Biomed Eng. 1989;17(5):451-529.

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Effects of static magnetic and pulsed electromagnetic fields on bone healing.

Darendeliler, M., Darendeliler, A., & Sinclair, P.

The effect of static magnetic fields and pulsed electromagnetic fields on bone healing in guinea pigs was investigated. The static magnetic fields were produced using neodymium magnets, and the magnetic field strengths that the guinea pigs were exposed to averaged about 500 gauss. The study concluded that "both static and pulsed electromagnetic fields seemed to accelerate the rate of bone repair when compared to the control group."

International Journal of Adult Orthodontic and Orthognathic Surgery, 1997;12, 43-53.

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Strong static magnetic field stimulates bone formation to a definite orientation in vitro and in vivo.

Kotani H, Kawaguchi H, Shimoaka T, Iwasaka M, Ueno S, Ozawa H, Nakamura K, Hoshi K.

Department of Biomedical Engineering, Graduate School of Medicine, University of Tokyo, Japan.

The induction of bone formation to an intentional orientation is a potentially viable clinical treatment for bone disorders. Among the many chemical and physical factors, a static magnetic field (SMF) of tesla order can regulate the shapes of blood cells and matrix fibers. This study investigated the effects of a strong SMF (8 T) on bone formation in both in vivo and in vitro systems. After 60 h of exposure to the SMF, cultured mouse osteoblastic MC3T3-E1 cells were transformed to rodlike shapes and were orientated in the direction parallel to the magnetic field. Although this strong SMF exposure did not affect cell proliferation, it up-regulated cell differentiation and matrix synthesis as determined by ALP and alizarin red stainings, respectively. The SMF also stimulated ectopic bone formation in and around subcutaneously implanted bone morphogenetic protein (BMP) 2-containing pellets in mice, in which the orientation of bone formation was parallel to the magnetic field. It is concluded that a strong SMF has the potency not only to stimulate bone formation, but also to regulate its orientation in both in vitro and in vivo models. This is the first study to show the regulation of the orientation of adherent cells by a magnetic field. We propose that the combination of a strong SMF and a potent osteogenic agent such as BMP possibly may lead to an effective treatment of bone fractures and defects.

J Bone Miner Res. 2002 Oct;17(10):1814-21.

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Use of physical forces in bone healing.

Nelson FR, Brighton CT, Ryaby J, Simon BJ, Nielson JH, Lorich DG, Bolander M, Seelig J.

Henry Ford Hospital, Detroit, MI, USA.

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.

J Am Acad Orthop Surg. 2003 Sep-Oct;11(5):344-54.

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Bone Formation

Effect of some electric signals transmitted by an induction coil on weight increase, incorporation of marker, and histological and ultrastructural appearance of the skeleton in a chick embryo.

Duriez R, Bassett A.

Embryo Chicks were exposed to various types of electrical impulses transmitted by induction coils between the 6th and 13th day of incubation. Compared with controls, the Chick tibias showed a highly significant increase in weight and length as well as increased incorporation of tritiated thymidine. In addition, the total weight of the treated embryos was significantly greater than that of the controls. The results suggest that the effects of these electro-magnetic fields, particularly their skeletal effects, act principally on cellular multiplication and/or enhanced cellular activity following an increase in protein synthesis.

C R Seances Acad Sci D. 1980 Jun 23;290(23):1483-6.

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Effects of static magnetic field on bone formation of rat femurs.

Yan QC, Tomita N, Ikada Y.

Institute for Frontier Medical Sciences, Kyoto University, Japan.

Effects of static magnetic fields (SMF) on bone formation of rat femurs, were evaluated using tapered rods made of magnetized and unmagnetized samarium cobalt of the same size. They were implanted transcortically into the middle diaphysis of rat femurs under press-fit loading. The bone mineral density (BMD) and bone calcium content were measured 12 weeks after implantation by dual-energy X-ray absorptiometry and chemical analysis with o-cresolphthalein complexon, respectively. The result revealed that the femurs adjacent to magnetized specimens had significantly higher BMD and calcium content than those adjacent to the unmagnetized specimen (p < 0.01). However, the value of BMD and calcium content of rats with magnetized specimens was similar to that of non-operated rats. No specific change was found in the body weight, serum Ca, activity of alkaline phosphatase, hemogram, and BMD of the tibia and humerus among the magnetized and unmagnetized. These results suggest that the long-term local SMF stimulation on the bone has a local effect to prevent the decrease in BMD caused by surgical invasion or implantation.

Med Eng Phys. 1998 Sep;20(6):397-402.

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Static magnetic field effects on bone formation of rats with an ischemic bone model.

Xu S, Tomita N, Ohata R, Yan Q, Ikada Y.

Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan.

Effects of a static magnetic field were studied on bone formation using an ischemic rat femur model. Metal rods were prepared from magnetized and unmagnetized samariun cobalt to have tapered structure, both with the same geometrical dimension, and were implanted transcortically into the middle diaphysis of 88 rat femurs. Both sides of the rat femoral artery were ligated to create an ischemic bone model, followed by implantation of the tapered rod to the femur. The bone mineral density (BMD) and weight of the femurs were measured at 1st and 3rd week after implantation.The result at the 3rd week post-implantation revealed that the BMD and weight of the ischemic bone model rats were significantly reduced, compared with that of non-operated femur. It was also found that the magnetized group had significantly higher bone weights than the unmagnetized (p<0.05). The BMD of the rats implanted with the magnetized rods were similar to those of the non-operated (p>0.05). This enhancement of the femoral bone formation of the ischemic rat model by the static magnetic field seems to be due to the improved blood circulation of the femur.

Biomed Mater Eng. 2001;11(3):257-63.

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Effects of pulsed electromagnetic field stimulation on distraction osteogenesis in the rabbit tibial leg lengthening model.

Fredericks DC, Piehl DJ, Baker JT, Abbott J, Nepola JV.

Bone Healing Research Laboratory, Department of Orthopaedic Surgery, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA. douglas-fredericks@uiowa.edu

The purpose of this study was to determine whether exposure to pulsed electromagnetic field (PEMF) would shorten the healing time of regenerate bone in a rabbit tibial distraction model. Beginning 1 day after surgery, mid-shaft tibial osteotomies, stabilized with external fixators, were distracted 0.25 mm twice daily for 21 days and received either no exposure (sham control) or 1 hour per day exposure to low-amplitude, low-frequency PEMF. Tibiae were tested for torsional strength after 9, 16, and 23 days post-distraction. PEMF-treated tibiae were significantly stronger than shams at all three time points. By 16 days post-distraction, the PEMF group had achieved biomechanical strength essentially equivalent to intact bone. Shams did not achieve normal biomechanical strength even after 23 days post-distraction. In this tibial distraction model, short daily PEMF exposures accelerated consolidation of regenerate bone. Clinical usefulness awaits testing.

J Pediatr Orthop. 2003 Jul-Aug;23(4):478-83.

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Effects of static magnetic fields on bone formation in rat osteoblast cultures.

Yamamoto Y, Ohsaki Y, Goto T, Nakasima A, Iijima T.

Departments of Orthodontics.

Although the promotional effects on osteoblasts of pulsed electromagnetic fields have been well-demonstrated, the effects of static magnetic fields (SMF) remain unclear; nevertheless, magnets have been clinically used as a 'force source' in various orthodontic treatments. We undertook the present investigation to study the effects of SMF on osteoblastic differentiation, proliferation, and bone nodule formation using a rat calvaria cell culture. During a 20-day culture, the values of the total area and the number and average size of bone nodules showed high levels in the presence of SMF. In the matrix development and mineralization stages, the calcium content in the matrix and two markers of osteoblastic phenotype (alkaline phosphatase and osteocalcin) also showed a significant increase. Accordingly, these findings suggest that SMF stimulates bone formation by promoting osteoblastic differentiation and/or activation.

J Dent Res. 2003 Dec;82(12):962-6.

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Fracture Healing

Treatment of wrist and hand fractures with natural magnets: preliminary report

Costantino C, Pogliacomi F, Passera F, Concari G.

The Authors, after having defined the phenomenon and the biological characteristics of natural magnets, evaluate their ability in accelerating the formation of bone callus in hand and wrist fractures compared to treatment with immobilization in a plaster cast. Forty patients (4 females and 37 males) between 20 and 86 years of age were treated. A small natural magnet was inserted in each of the plaster casts (diameter: 2cm, height: 0.5cm) made of 4 blocks in Neodymium-Iron-Boron, capable of generating 4 magnetic poles (2 positive and 2 negative) of diagonal alternate polarity that produced a symmetric, quadruple static magnetic field. The created magnetic flow was wavelike, concentrated in one direction, and developed a force up to 12,500 gauss. From this study it has emerged that inserting a quadruple magnet in a plaster cast in hand and wrist fractures results in the formation of bone callus in an average time that is 35% inferior [shorter] to the standard time. Accelerating the healing of the fracture is important since it reduces immobilization time for the joints involved, avoiding subsequent weakness and stiffness and allowing the patient to begin rehabilitative physiotherapy sooner, which permits a faster functional recovery.

Acta bio-medica: Atenei Parmensis 2007 Dec;78(3):198-203. PMID: 18330079

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Modification of fracture repair with selected pulsing electromagnetic fields.

Bassett CA, Valdes MG, Hernandez E.

We assayed different pulsing electromagnetic fields for their effects on the mechanical and histological repair properties of an osteotomy of the radius of the rat fourteen days postoperatively. Highly significant differences were found in the control and experimental initial load values and their decay as a function of time. These results correlate well with the histological pattern in the bridging callus. A pulse that produces an increase (above the control level) in initial load by a factor of 2.4 and a slower decay was characterized by more extensive calcification of fibrocartilage and its replacement by fibrous bone at this early, but important, stage in fracture-healing.

J Bone Joint Surg Am. 1982 Jul;64(6):888-95.

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Effect of a static magnetic field on fracture healing in a rabbit radius. Preliminary results.

Bruce GK, Howlett CR, Huckstep RL.

To ascertain what effect a static magnetic force has on a healing fracture, samarium cobalt magnets were implanted adjacent to induced radial fractures in adult rabbits. A magnetic field of 220-260 G was generated at the fracture site. The radii were allowed to heal for four weeks and the contralateral fractured bones acted as controls. Healing bone units were assessed microscopically and mechanically. Significantly greater forces (p less than 0.01) were required to break those bone units exposed to magnetic fields. However, no significant difference was found when comparing the longitudinal midcallus areas from magnetized and nonmagnetized limbs.

Clin Orthop 1987 Sep;(222):300-6.

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Effects of electromagnetic fields in experimental fracture repair.

Otter MW, McLeod KJ, Rubin CT.

Program in Biomedical Engineering, State University of New York at Stony Brook 11794-8181, USA.

The clinical benefits of electromagnetic fields have been claimed for 20 centuries, yet it still is not clear how they work or in what circumstances they should be used. There is a large body of evidence that steady direct current and time varying electric fields are generated in living bone by metabolic activity and mechanical deformation, respectively. Externally supplied direct currents have been used to treat nonunions, appearing to trigger mitosis and recruitment of osteogenic cells, possibly via electrochemical reactions at the electrode-tissue interface. Time varying electromagnetic fields also have been used to heal nonunions and to stabilize hip implants, fuse spines, and treat osteonecrosis and osteoarthritis. Recent research into the mechanism(s) of action of these time varying fields has concentrated on small, extremely low frequency sinusoidal electric fields. The osteogenic capacity of these fields does not appear to involve changes in the transmembrane electric potential, but instead requires coupling to the cell interior via transmembrane receptors or by mechanical coupling to the membrane itself.

Clin Orthop. 1998 Oct;(355 Suppl):S90-104.

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Pulsed electromagnetic fields for the treatment of bone fractures.

Satter Syed A, Islam MS, Rabbani KS, Talukder MS.

Industrial Physics Division, BCSIR Laboratories, Dhaka.

The effectiveness of electrical stimulation and Pulsed Electro Magnetic Field (PEMF) stimulation for enhancement of bone healing has been reported by many workers. The mechanism of osteogenesis is not clear, therefore, studies look for empirical evidence. The present study involved a clinical trial using low amplitude PEMF on 19 patients with non-union or delayed union of the long bones. The pulse system used was similar in shape to Bassett's single pulse system where the electric voltage pulse was 0.3 mSec wide repeating every 12 mSec making a frequency of about 80 Hz. The peak magnetic fields were of the order of 0.01 to 0.1 m Tesla, hundred to thousand times smaller than that of Bassett. Among the 13 who completed this treatment schedule the history of non-union was an average of 41.3 weeks. Within an average treatment period of 14 weeks, 11 of the 13 patients had successful bone healing. The two unsuccessful cases had bone gaps greater than 1 cm following removal of dead bone after infection. However, use of such a low field negates Bassett's claim for a narrow window for shape and amplitude of wave form, and justifies further experimental study and an attempt to understand the underlying mechanism.

Bangladesh Med Res Counc Bull. 1999 Apr;25(1):6-10.

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Non-operative salvage of surgically-resistant pseudarthroses and non-unions by pulsing electromagnetic fields. A preliminary report.

Bassett CA, Pilla AA, Pawluk RJ.

This report documents, for the first time, to the authors' knowledge, the therapeutic use in humans of low energy, electromagnetic fields pulsing in the extremely low frequency (E.L.F.) range. These fields, established outside the body, were used to treat congenital and acquired pseudarthroses and non-unions. Energy of this type appears to affect biological processes, not through heat production, but through electrically-induced changes in the environment of cells within the organism. Of the 29 patients included in the study, 17 had experienced at least one failure of surgical repair and, in each of these, amputation had been recommended. The overall success rate, including those patients treated with inadequate pulse characteristics and those who failed to follow the protocol, was in excess of 70 per cent. Improvements in the specificity of pulse characteristics hold promise for increasing the rate of success. The simple, clinical methodology, which is conducted on an out-patient basis, appears to be both safe and effective. It can be applied with or without surgery. This approach requires additional controlled investigations before it is ready for general use in the orthopaedic community. The indications for amputation of surgically-resistant pseudarthroses, however, should be reassessed. The principles and technology, which have been established during this endeavor, may have physiologic and practical significance for processes other than pseudarthrosis and non-union.

Clin Orthop. 1977 May;(124):128-43.

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Acceleration of repair of non-unions by electromagnetic fields.

Sedel L, Christel P, Duriez J, Duriez R, Evrard J, Ficat C, Cauchoix J, Witvoet J.

This work deals with the results obtained by four French orthopaedic departments using the electromagnetic field stimulation for non union treatment. This is the method established by A. Bassett. 37 cases are studied, the results are known for 35 of them with 6 failures and 29 successes. The failures can be explained for four of them by a bad application of the device. Concerning the 29 successful cases, the role of the stimulation is discussed. Discarding those who have been treated a short time after a surgical procedure, those who have been immobilized more than 6 months and those where the non union could have been a delayed union, it remains 14 successful cases apparently undisputable. For them the role of the electromagnetic field stimulation seems real.

Rev Chir Orthop Reparatrice Appar Mot. 1981;67(1):11-23.

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Treatment of ununited tibial diaphyseal fractures with pulsing electromagnetic fields.

Bassett CA, Mitchell SN, Gaston SR.

One hundred and twenty-five patients with one hundred and twenty-seven ununited fractures of the tibial diaphysis were treated exclusively with pulsing electromagnetic fields. The over-all success rate in healing of the fracture with this surgically non-invasive out-patient method was 87 per cent. The success rate was not materially affected by the age or sex of the patient, the length of prior disability, the number of previous failed operations, or the presence of infection or metal fixation.

J Bone Joint Surg Am. 1981 Apr;63(4):511-23.

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Treatment of therapeutically resistant non-unions with bone grafts and pulsing electromagnetic fields.

Bassett CA, Mitchell SN, Schink MM.

This study reviews the cases of eighty-three adults with ununited fractures who were treated concomitantly with bone-grafting and pulsed electromagnetic fields. An average of 1.5 years had elapsed since fracture and the use of this combined approach. Nearly one-third of the patients had a history of infection, and an average of 2.4 prior operations had failed to produce bone union. Thirty-eight patients who were initially treated with grafts and pulsed electromagnetic fields for ununited fractures with wide gaps, synovial pseudarthrosis, and malalignment achieved a rate of successful healing of 87 per cent. Forty-five patients who had initially been treated unsuccessfully with pulsing electromagnetic fields alone had bone-grafting and were re-treated with pulsing electromagnetic fields. Ninety-three per cent of these fractures healed. The residual failure rate after two therapeutic attempts, one of which was operative, was 1.5 per cent. The median time to union for both groups of patients was four months.

J Bone Joint Surg Am. 1982 Oct;64(8):1214-20.

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The development and application of pulsed electromagnetic fields (PEMFs) for ununited fractures and arthrodeses.

Bassett CA.

This article deals with the rational and practical use of surgically noninvasive pulsed electromagnetic fields (PEMFs) in treating ununited fractures, failed arthrodeses, and congenital pseudarthroses (infantile nonunions). The method is highly effective (more than 90 per cent success) in adult patients when used in conjunction with good management techniques that are founded on biomechanical principles. When union fails to occur with PEMFs alone after approximately four months, their proper use in conjunction with fresh bone grafts insures a maximum failure rate of 1 to 1.5 per cent. Union occurs because the weak electric currents induced in tissues by the time-varying fields effect calcification of the fibrocartilage in the fracture gap, thereby setting the stage for the final phases of fracture healing by endochondral ossification. The efficacy, safety, and simplicity of the method has prompted its use by the majority of orthopedic surgeons in this country. In patients with delayed union three to four months postfracture, PEMFs appear to be more successful and healing, generally, is more rapid than in patients managed by other conservative methods. For more challenging problems such as actively infected nonunions, multiple surgical failures, long-standing (for example, more than two years postfracture) atrophic lesions, failed knee arthrodeses after removal of infected prostheses, and congenital pseudarthroses, success can be expected in a large majority of patients in whom PEMFs are used. Finally, as laboratory studies have expanded knowledge of the mechanisms of PEMF action, it is clear that different pulses affect different biologic processes in different ways. Selection of the proper pulse for a given pathologic entity has begun to be governed by rational processes similar, in certain respects, to those applied to pharmacologic agents.

Orthop Clin North Am. 1984 Jan;15(1):61-87.

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Results of pulsed electromagnetic fields (PEMFs) in ununited fractures after external skeletal fixation.

Marcer M, Musatti G, Bassett CA.

Of 147 patients with fractures of the tibia, femur and humerus, in whom an average of 3.3 operations had failed to produce union, all were treated with external skeletal fixation in situ and pulsed electromagnetic fields (PEMFs). Of the 147, 107 patients united for an overall success rate of 73%. Union of the femur occurred in 81% and the tibia in 75%. Only five of 13 humeri united. Failure to achieve union with PEMFs was most closely associated with very wide fracture gaps and insecure skeletal fixation devices.

Clin Orthop. 1984 Nov;(190):260-5.

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Healing of nonunion of a fractured lateral condyle of the humerus by pulsing electromagnetic induction.

Das Sarkar S, Bassett CA.

Department of Orthopaedic Surgery, Sandwell District General Hospital, Lyndon, West Midlands, United Kingdom.

Nonoperative salvage of a surgically resistant case of established nonunion of a fracture of the lateral condyle of the humerus in a child is described. Solid union was achieved by treatment with pulsed electromagnetic fields. A review of the literature indicates that this is the first published report of such a case.

Contemp Orthop. 1991 Jan;22(1):47-51.

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Pseudoarthrosis

Pulsing electromagnetic field treatment in ununited fractures and failed arthrodeses.

Bassett CA, Mitchell SN, Gaston SR.

Pulsing electromagnetic fields (PEMFs) induce weak electric currents in bone by external coils on casts or skin. This surgically noninvasive, outpatient method, approved by the Food and Drug Administration in November 1979, produced confirmed end results in 1,007 ununited fractures and 71 failed arthrodeses, worldwide. Overall success at Columbia-Presbyterian Medical Center was 81%; internationally, 79%; and in other patients in the United States, 76%. Treatment with PEMFs was effective in 75% of 332 patients (a subset) with an average 4.7-year disability duration, an average of 3.4 previous operative failures to produce union, and a 35% rate of infection. Eighty-four percent of carpal naviculars and 82% of femoral neck-trochanteric nonunions were united. After attempted arthrodeses could not salvage a failed total-knee prosthesis, PEMFs promoted healing in 85% of patients. When coils were unsuccessful alone, combining them with surgical repair was effective.

JAMA. 1982 Feb 5;247(5):623-8.

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Congenital "pseudarthroses" of the tibia: treatment with pulsing electromagnetic fields.

Bassett CA, Caulo N, Kort J.

During the past seven years, 34 patients with infantile nonunions associated with congenital "pseudarthroses" completed treatment with pulsing electromagnetic fields (PEMFs). An analysis of results reveals that 17/34 (50%) have achieved complete healing with biomechanically sound union and radiographic demonstration of remedullarization. Union with function, i.e., healing with continued need for protection, was achieved in 7/34 (21%). Failure was the outcome in 10/34 patients (29%). Most of these occurred in males with a history of early fracture (less than 1 year) and with spindled, hypermobile lesions (Type III). During the early period of the study, PEMFs were the sole means of treatment. After a "coil effect" had been demonstrated, surgical realignment, immobilization and grafting were combined with PEMF treatment. Fundamentals of orthopedic management developed by the larger experience with adult nonunions were found to apply equally to infantile nonunions treated with PEMFs. These include effective immobilization of the fracture site and controlled "stress working" during recovery to facilitate gradual remodeling. PEMFs have been demonstrated to be a potentially useful adjunct in the orthopedic surgeon's armamentarium for treating infantile nonunions (congenital "pseudarthroses").

Clin Orthop. 1981 Jan-Feb;(154):136-48.

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Congenital pseudoarthrosis of the tibia: treatment with pulsing electromagnetic fields.

Kort JS, Schink MM, Mitchell SN, Bassett CA.

Ninety-two patients with congenital pseudoarthrosis (infantile nonunion) were treated with pulsing electromagnetic fields (PEMF) in the United States and Europe in the past eight years. This represents the largest group of patients with infantile nonunions in which a common treatment modality has been used. Excluding the ten lesions (11%) which healed with refracture 48 lesions (59%) healed whereas 34 (41%) failed to heal. The success rate in 23 type I and 34 Type II lesions was 77% and 76%, respectively. Surgery in association with PEMF treatment did not improve the results of treatment. The most important variable was the radiographic morphology of the nonunion gap. Patients with spindled bone ends, a large gap and a grossly mobile lesion had a very poor prognosis relative to patients with a cystic or sclerotic transverse fracture line with a gap of less than 5 mm. The key to success in the treatment of infantile nonunions has been the combination of PEMF treatment with good orthopedic management, consisting of rigid immobilization, a nonweight-bearing status and rehabilitation with impact loading exercise. Infantile nonunion remains a major challenge to the orthopedic surgeon, but PEMFs appear to offer some important advantages for overcoming this pernicious condition. Dr. Harold Boyd's discussion of this paper follows. It was his final address to the AAOS.

Clin Orthop. 1982 May;(165):124-37.

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Pulsing electromagnetic fields to achieve arthrodesis of the knee following failed total knee arthroplasty. A preliminary report.

Bigliani LU, Rosenwasser MP, Caulo N, Schink MM, Bassett CA.

Treatment with pulsing electromagnetic fields was used as an adjunct in twenty patients who had had a knee arthrodesis after failure of a total joint arthroplasty. Eighteen had had an infected arthroplasty; one, mechanical loosening; and one, recurrent dislocation. Arthrodesis had been attempted twenty-five times in these twenty patients prior to application of the coils. These procedures included the use of twenty-two external fixation frames, one compression plate, one intramedullary rod, and one cylinder cast. Two groups of patients were identified: those with non-union and those with delayed union. Fourteen patients began treatment six months or more after arthrodesis and were considered to have a non-union. The other six patients started treatment less than six months after attempted arthrodesis because there was no evidence of progression toward union. They were considered to have delayed union. In seventeen (85 per cent) of the twenty patients a clinically solid arthrodesis with roentgenographic evidence of bone-bridging was achieved. The average time to union after coil therapy was started was 5.8 months, with a range of three to twelve months. The patients who started coil treatment earlier after arthrodesis showed a tendency to heal faster. The three patients who had failures were the only ones who did not adhere to the protocol, and all three were in the non-union group. All patients with a solid arthrodesis were free of pain and able to walk at the time of follow-up, nine to thirty-one months after the completion of treatment. The use of pulsing electromagnetic fields appears to be a valuable non-invasive adjunct when performing arthrodesis of the knee after failed total joint arthroplasty.

J Bone Joint Surg Am. 1983 Apr;65(4):480-5.

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Long-term pulsed electromagnetic field (PEMF) results in congenital pseudarthrosis.

Bassett CA, Schink-Ascani M.

Bioelectric Research Center, Riverdale, New York 10463.

Ninety-one patients with congenital pseudarthrosis of the tibia have been treated with pulsed electromagnetic fields (PEMFs) since 1973 and all except 4 followed to puberty. Lesions were stratified by roentgenographic appearance. Type I and type II had gaps less than 5 mm in width. Type III were atrophic, spindled, and had gaps in excess of 5 mm. Overall success in type I and II lesions was 43 of 60 (72%). Of those 28 patients seen before operative repair had been attempted, 7 of 8 type I lesions healed (88%), whereas 16 of 20 type II lesions healed (80%) on PEMFs and immobilization alone. Only 19% (6 of 31) type III lesions united, only one of which did not require surgery. Sixteen of 91 limbs (18%) were ultimately amputed, most before treatment principles were fully defined in 1980. Fourteen of these 16 patients (88%) had type III lesions. Refracture occurred in 22 patients, most as the result of significant trauma, in the absence of external brace support. Twelve of the 19 refractures, retreated with PEMFs and casts, healed on this regime. Episodic use of PEMFs proved effective in controlling stress fractures in several patients until they reached puberty. PEMFs, which are associated with no known risk, appear to be an effective, conservative adjunct in the management of this therapeutically challenging, congenital lesions.

Calcif Tissue Int. 1991 Sep;49(3):216-20.

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The effect of postoperative electromagnetic pulsing on canine posterior spinal fusions.

Kahanovitz N, Arnoczky SP, Hulse D, Shires PK.

An experimental canine study was devised to evaluate the efficacy of a noninvasive adjunct to improve the rate and quality of the posterior fusion mass over the standard surgical technique. Ten large adult mongrel dogs underwent a three-level lumbar spinal fusion. Bone excised from the spinous processes was packed in removed facet joints and over the decorticated laminae. To insure rigid internal fixation, custom-made distraction instrumentation was placed bilaterally under the laminae of the vertebrae above and below the three fused vertebrae. Five dogs underwent electromagnetic pulsing, and five dogs acted as controls. Two dogs were sacrificed at 4, 6, 9, 12, and 15 weeks to assess the radiographic and histologic status of the fusion mass. Preoperative and preautopsy hematologic studies as well as gross and histologic autopsy specimens revealed no abnormalities attributable to the electromagnetic pulsing. High-resolution radiography and histologic studies showed earlier incorporation of the graft, improved new bone formation, and better organization of the fusion mass in the 4-, 6-, and 9-week stimulated specimens. However, by 12 and 15 weeks there did not appear to be any histologic or radiographic differences between the stimulated and control dogs. Although electromagnetic pulsing appears to produce an early accelerated osteogenic response, it does not appear to improve the overall results of primary canine spinal fusions.

Spine. 1984 Apr;9(3):273-9.

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Treatment of failed posterior lumbar interbody fusion (PLIF) of the spine with pulsing electromagnetic fields.

Simmons JW.

This paper presents a technique and discusses the results of treating failed posterior lumbar interbody fusions (PLIFs) of the spine with pulsing electromagnetic fields (PEMFs). Thirteen male patients suffering from failed PLIFs, with an average time of 40 months since the last surgical fusion attempt, were the subjects of this study. PEMFs were applied by the patient according to strict criteria but in the comfort of their home. Initial and subsequent medical evaluations closely monitored the patient's condition and progress. PEMFs promoted a significant increase in bone formation in 85% (11 of 13) of the patient pool and achieved body-to-body fusion throughout the intervertebral disc space in 77% (ten of 13) over the treatment period. The treatment required no hospitalization, reduced morbidity, and avoided the risks associated with surgical intervention. The results suggest that this surgically noninvasive outpatient therapy may become a successful alternative treatment of failed PLIF.

Clin Orthop. 1985 Mar;(193):127-32.

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Effects of pulsing electromagnetic fields (PEMF) on the course of vertebral fusion callus. A histological study.

Guizzardi S, Di Silvestre M, Govoni P, Strocchi R, Scandroglio R.

Istituto di Istologia ed Embriologia Generale, Universita degli Studi di Parma.

In this paper the findings concerning the effectiveness of PEMF on the evolution of the vertebral fusion callus are reported. The study has been carried on by preparing postero-lateral arthrodesis in the lumbar spinal tract in rats. In this tract the laminae have been decorticated, the articular processes prepared by decortication and removal of the articular cartilage, and the spinal processes removed and employed as osteoinductive material. The rats sacrificed after 4 and 8 weeks, show how the decorticated areas are clearly influenced from PEMF, an early appearance of the bony fusion callus is already evident in the treated group just after 4 weeks. Also the articular areas are influenced from PEMF but less markedly than the decorticated one; in these areas after 8 weeks the fusion callus is prevalently cartilaginous even if areas of calcification are detectable inside. This different behaviour can be explained with the absence of any form of spinal fusion by means of surgical tools.

Acta Biomed Ateneo Parmense. 1990;61(5-6):227-35.

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A randomized double-blind prospective study of the efficacy of pulsed electromagnetic fields for interbody lumbar fusions.

Mooney V.

Division of Orthopaedic Surgery, University of California, Irvine.

A randomized double-blind prospective study of pulsed electromagnetic fields for lumbar interbody fusions was performed on 195 subjects. There were 98 subjects in the active group and 97 subjects in the placebo group. A brace containing equipment to induce an electromagnetic field was applied to patients undergoing interbody fusion in the active group, and a sham brace was used in the control group. In the active group there was a 92% success rate, while the control group had a 65% success rate (P greater than 0.005). The effectiveness of bone graft stimulation with the device is thus established.

Spine. 1990 Jul;15(7):708-12.

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Effects of smoking and maturation on long-term maintenance of lumbar spinal fusion success.

Mooney V, McDermott KL, Song J.

Department of Orthopaedics, University of California San Diego, USA.

This is a follow-up study of a multicenter, randomized, placebo-controlled clinical trial conducted in accordance with the condition for Food and Drug Administration approval for pulsed electromagnetic fields. The purpose of this study was to evaluate the long-term efficacy and safety of pulsed electromagnetic fields for spinal fusion. An earlier clinical trial study was conducted to evaluate the efficacy of Pulsed Electromagnetic Fields to enhance fusion success at one year follow-up. In the original study, 195 patients undergoing interbody fusion were enrolled. Of the 195 patients, 98 were in the active group and 97 were in the placebo group. Study results showed a 92% successful fusion rate in the active group compared to 68% in the placebo group. For this long-term follow-up study, all patients who had healed in the original study were recalled for a follow-up radiograph. Radiographs were assessed by the attending surgeon for fusion assessment, when possible. The results of this long-term follow-up study showed that there was a reduction in maintenance of the fusion over time by 25%, but that the reduction was unrelated to treatment group and correlated statistically with whether the patient was a smoker.

J Spinal Disord. 1999 Oct;12(5):380-5.

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Pulsing electromagnetic fields (PEMFs) in spinal fusion: preliminary clinical results.

Di Silvestre M, Savini R.

Istituto Ortopedico Rizzoli, Bologna.

Pulsing electromagnetic fields (PEMFs) were used during the postoperative management of 31 patients submitted to lumbosacral posterolateral fusion (PLF). The fusions were stimulated with PEMFs during the first 2 of the 4 months of postoperative immobilization. Consolidation of PLF was obtained in 20 of the 31 patients after 2 months of stimulation, thus, healing time was cut in half. After 4 months, fusion was observed in 30 out of the 31 cases submitted to stimulation (96%).

Chir Organi Mov. 1992 Jul-Sep;77(3):289-94.

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Pulsed electromagnetic field stimulation on posterior spinal fusions: a histological study in rats.

Guizzardi S, Di Silvestre M, Govoni P, Scandroglio R.

Institute of Histology and Embryology, University of Parma, Italy.

This study reports the histological data relative to the effect of pulsed electromagnetic fields (PEMFs) on the evolution of posterior arthrodesis induced in the lumbar vertebrae of 12 adult male Sprague-Dawley rats. After the operation, one group of six rats was stimulated with PEMFs for 18 h per day, by means of a pair of coils fixed to the outside of the cage. A control group of six rats was given no stimulation after surgery. In the groups stimulated with PEMFs an acceleration of the process of bone callus organization was already observed after 4 weeks, and even more so after 8: An early replacement was in fact observed of the newly formed cartilage tissue with primary bone (at 4 weeks) and subsequently with secondary bone (after 8 weeks).

J Spinal Disord. 1994 Feb;7(1):36-40.

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The effect of pulsed electromagnetic fields on instrumented posterolateral spinal fusion and device-related stress shielding.

Ito M, Fay LA, Ito Y, Yuan MR, Edwards WT, Yuan HA.

Department of Orthopaedics, Hokkaido University School of Medicine, Sapporo, Japan.

STUDY DESIGN: This study was designed to examine stress-shielding effects on the spine caused by rigid implants and to investigate the effects of pulsed electromagnetic fields on the instrumented spine.

OBJECTIVES: To investigate the effects of pulsed electromagnetic fields on posterolateral spinal fusion, and to determine if osteopenia induced by rigid instrumentation can be diminished by pulsed electromagnetic fields.

SUMMARY OF BACKGROUND DATA: Although device-related osteopenia on vertebral bodies is of a great clinical importance, no method for preventing bone mineral loss in vertebrae by stiff spinal implants has been effective.

METHODS: Twenty-eight adult beagles underwent L5-L6 destabilization followed by posterolateral spinal fusion. The study was divided into four groups: 1) Group CNTL: without instrumentation, without pulsed electromagnetic fields, 2) Group PEMF: without Steffee, with pulsed electromagnetic fields, 3) Group INST: with Steffee, without pulsed electromagnetic fields, 4) Group PEMF + INST: with Steffee, with pulsed electromagnetic fields. At the end of 24 weeks, the dogs were killed, and L4-L7 segments were tested biomechanically without instrumentation. Radiographs and quantitative computed tomography assessed the condition of the fusion mass.

RESULTS: Stress shielding was induced in the anterior vertebral bodies of L6 with the Steffee plates; bone mineral density was increased with the addition of pulsed electromagnetic fields, regardless of the presence or absence of fixation. A decrease in flexion and bending stiffness was observed in the Group INST; pulsed electromagnetic fields did increase the flexion stiffness regardless of the presence or absence of fixation, although this was not statistically significant.

CONCLUSIONS: Use of pulsed electromagnetic fields has the potential to minimize device-related vertebral-bone mineral loss.

Spine. 1997 Feb 15;22(4):382-8.

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Use of electromagnetic fields in a spinal fusion. A rabbit model.

Glazer PA, Heilmann MR, Lotz JC, Bradford DS.

Department of Orthopaedic Surgery, University of California, San Francisco, USA.

STUDY DESIGN: The biomechanical and histologic characteristics of posterolateral spinal fusion in a rabbit model with and without the application of a pulsed electromagnetic field were analyzed in a prospective, randomized trial. In addition, fusion rate with and without a pulsed electromagnetic field in this model was assessed by biomechanical testing, radiographs, and manual palpation.

OBJECTIVES: To evaluate the influence of a pulsed electromagnetic field on the spinal fusion rate and biomechanical characteristics in a rabbit model.

SUMMARY OF BACKGROUND DATA: Previous studies performed to assess the benefits of a pulsed electromagnetic field in spinal fusion have been complicated by the use of instrumentation, and the animal models used do not have a pseudarthrosis rate comparable to that seen in humans. In contrast, the posterolateral intertransverse process fusion in the rabbit is uncomplicated by the use of instrumentation and has been shown to have a pseudarthrosis rate similar to that found in humans (5-35%). METHODS: Ten New Zealand white rabbits each were randomly assigned to undergo spinal fusion using either 1) autologous bone with electromagnetic fields, or 2) autologous bone without electromagnetic fields. A specially designed plastic constraint was used to focus the pulsed electromagnetic field over the rabbits' lumbar spine 4 hours per day. Animals were killed at 6 weeks for biomechanical and histologic testing.

RESULTS: The rate of pseudarthrosis, as evaluated radiographically and manually in a blinded fashion, decreased from 40% to 20% with the pulsed electromagnetic field, but this decrease in the nonunion rate was not statistically significant given the number of animals per group. Biomechanical analysis of the fusion mass showed that a pulsed electromagnetic field resulted in statistically significant increases in stiffness (35%), area under the load-displacement curve (37%), and load to failure of the fusion mass (42%). Qualitative histologic assessment showed increased bone formation in those fusions exposed to a pulsed electromagnetic field.

CONCLUSIONS: This study demonstrates the reproducibility of a rabbit fusion model, and the ability of a pulsed electromagnetic field to induce a statistically significant increase in stiffness, area under the load-displacement curve, and load to failure of the fusion mass. This investigation provides a basis for continued evaluation of biologic enhancement of spinal arthrodesis with the use of a pulsed electromagnetic field.

Spine. 1997 Oct 15;22(20):2351-6.

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Outcomes after posterolateral lumbar fusion with instrumentation in patients treated with adjunctive pulsed electromagnetic field stimulation.

Bose B.

Medical Center of Delaware, Newark, USA.

Fusion success and clinical outcome were determined in 48 high-risk patients who underwent posterolateral lumbar fusions with internal fixation and were treated with adjunctive pulsed electromagnetic field (PEMF) stimulation postoperatively. An independent radiographic assessment demonstrated a success rate of 97.9%. Following treatment, 59% of the working patients returned to their employment. Overall clinical assessment was excellent in 4.2% of patients, good in 79.2%, and fair in 16.7%; no patient had a poor clinical assessment.

Adv Ther. 2001 Jan-Feb;18(1):12-20.

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Electrical stimulation of spinal fusion: a scientific and clinical update

Kahanovitz N.

Hospital for Joint Diseases, 301 E. 17th Street, New York, NY 10003, USA. nkspinemd@aol.com

BACKGROUND CONTEXT: For over two decades, a number of electrical stimulation devices have achieved increasing acceptance as adjuncts to lumbar spinal fusion. Direct current electrical stimulation, pulsed electromagnetic fields and more recently capacitive coupling have been shown to have varying effectiveness when used to increase the success of lumbar spinal fusion.

PURPOSE: The various electrical stimulation devices will be reviewed with respect to the available basic science evidence validating their use as spinal fusion adjuncts, as well as a review of the current clinical data available to allow not only a discussion of their overall clinical applicability, but more specifically their use in specific spinal disorders and spinal fusion techniques.

METHODS: The existing peer-reviewed scientific literature will be used to ascertain the scientific and clinical efficacy of electrical stimulation to enhance lumbar spinal fusion.

CONCLUSION: Electrical stimulation devices have emerged as valid adjuncts to attaining a solid lumbar spinal fusion. However, not all stimulators are equally scientifically effective nor are they equally effective clinically in achieving increased fusion success.

Spine J. 2002 Mar-Apr;2(2):145-50.

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Combined magnetic fields accelerate and increase spine fusion: a double-blind, randomized, placebo controlled study.

Linovitz RJ, Pathria M, Bernhardt M, Green D, Law MD, McGuire RA, Montesano PX, Rechtine G, Salib RM, Ryaby JT, Faden JS, Ponder R, Muenz LR, Magee FP, Garfin SA.

San Dieguito Orthopaedics, Encinitas, California 92024, USA. rjlmd@pacbell.net

STUDY DESIGN: The clinical study conducted was a prospective, randomized, double-blind, placebo-controlled trial.

OBJECTIVES: The purpose of this study was to evaluate the effect of combined magnetic fields on the healing of primary noninstrumented posterolateral lumbar spine fusion.

SUMMARY OF BACKGROUND DATA: Combined magnetic fields, a new type of biophysical stimulus, have been shown to act by stimulating endogenous production of growth factors that regulate the healing process. This is the first placebo-controlled study to assess the effect of an electromagnetic stimulus on primary noninstrumented posterolateral lumbar spine fusion surgery as well as the first evaluation of combined magnetic fields as an adjunctive stimulus to lumbar spine fusion.

METHODS: This multicenter investigational study was conducted at 10 clinical sites under an Investigational Device Exemption from the United States Food and Drug Administration. Eligible patients had one-level or two-level fusions (between L3 and S1) without instrumentation, either with autograft alone or in combination with allograft. The combined magnetic field device used a single posterior coil, centered over the fusion site, with one 30-minute treatment per day for 9 months. Randomization was stratified by site and number of levels fused. Evaluation was performed 3, 6, and 9 months after surgery and 3 months after the end of treatment. The primary endpoint was assessment of fusion at 9 months, based on radiographic evaluation by a blinded panel consisting of the treating physician, a musculoskeletal radiologist, and a spine surgeon.

RESULTS: Of 243 enrolled patients, 201 were available for evaluation. Among all patients with active devices, 64% healed at 9 months compared with 43% of patients with placebo devices: a significant difference (P = 0.003 by Fisher's exact test). Stratification by gender showed fusion in 67% of women with active devices, compared with 35% of those with placebo devices (P = 0.001 by Fisher's exact test). By contrast, there was not a statistically significant effect of the active device in this male study population. In the overall population of 201 patients, repeated measures analyses of fusion outcomes (by generalized estimating equations) showed a main effect of treatment, favoring the active treatment (P = 0.030). In a model with main effect and a time by treatment interaction, the latter was significant (P = 0.024), indicating acceleration of healing. Performed in the full sample of 243 patients, results of the intent-to-treat analysis were qualitatively the same as in the evaluable sample of 201 patients.

DISCUSSION: This investigational study demonstrates that combined magnetic field treatment of 30 min/d increases the probability of successful spine fusion, and statistical analysis using the generalized estimating equations model suggests an acceleration of the healing process. This is the first randomized clinical trial of noninstrumented primary posterolateral lumbar spine fusion, with evaluation by a blinded, unbiased panel. This is the first double-blind study performed to date assessing noninstrumented fusion outcome with extremely critical radiographic criteria. The lower overall fusion rates in this study are attributed to the high-risk patient group with an average age of 57 years, the use of noninstrumented technique with posterolateral fusion only, and the reliance on extremely critical radiographic and clinical criteria and blinded panel for fusion assessment without surgical confirmation.

CONCLUSIONS: In conclusion, the adjunctive use of the combined magnetic field device was statistically beneficial in the overall patient population, as has been shown in previous studies of adjunctive bone growth stimulation for spine fusion. For the first time, stratification of fusion success data by gender demonstrated that the female study population responded positively to the adjunctive combined magnetic field treatment, with no statistically significant effect observed in the male study population. Adjunctive use of the combined magnetic field device significantly increased the 9-month success of radiographic spinal fusion and showed an acceleration of the healing process.

Spine. 2002 Jul 1;27(13):1383-9; discussion 1389.

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Osteonecrosis

Osteonecrosis of the femoral head treated by pulsed electromagnetic fields (PEMFs): a preliminary report.

Eftekhar NS, Schink-Ascani MM, Mitchell SN, Bassett CA.

This has been a preliminary report with a short-term follow-up of a small number of observations (28 hips of 24 patients). The follow-ups ranged from 6 to 36 months, with an average of 17.8 months. Only eleven hips (in eleven patients) were followed an average of 8 months after cessation of the treatment. It should be emphasized that this was a "pilot" study, in which no control series was used to determine the natural course of the disease in a comparable clinical setting. Of note was the pain relief, in 19 of 23 patients with moderate to severe pretreatment pain. Also there was an improved function, which suggests that at least in approximately two thirds of the patients there was some clinical benefit from this mode of treatment. In eight hips, clinical conditions did not change; and in two they worsened, requiring further treatment. Eighteen remaining hips were thought to have been benefited by the treatment. Six femoral heads that had already developed varying degrees of collapse (Ficat Type III) collapsed further (1 to 2 mm), and two round heads (Ficat II) progressed to off-round (Ficat III). This preliminary study suggests that further exploration of pulsed electromagnetic fields (PEMFs) is warranted in the treatment of osteonecrosis of the femoral head.

Hip. 1983;:306-30.

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Effects of pulsed electromagnetic fields on Steinberg ratings of femoral head osteonecrosis.

Bassett CA, Schink-Ascani M, Lewis SM.

New York Orthopaedic Hospital, Columbia Presbyterian Medical Center, Riverdale, NY 10463.

Between 1979 and 1985, 95 patients with femoral head osteonecrosis met the protocol for treatment of 118 hips with selected pulsed electromagnetic fields (PEMFs). Etiologies included trauma (17), alcohol (9), steroid use (46), sickle cell disease (2), and idiopathy (44). The average age was 38 years, and the average follow-up period since the onset of symptoms was 5.3 years. PEMF treatment had been instituted an average of 4.1 years earlier. By the Steinberg quantitative staging method of roentgenographic analysis, none of the 15 hips in Stages 0-III showed progression, and grading improved in nine of 15. Eighteen of 79 hips (23%) with Stage IV lesions progressed and none improved. In the Stage V category, one of 21 hips (5%) worsened and none improved. Three Stage VI lesions were unchanged. The overall rate of quantified progression for the 118 hips, 87% of which had collapse present when entering the program, was 16%. This value represents a reversal of the percentage of progression reported recently by other investigators using conservative and selected surgical methods. PEMF patients also have experienced long-term improvements in symptoms and signs, together with a reduction in the need for early joint arthroplasty.

Clin Orthop. 1989 Sep;(246):172-85.

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Use of pulsed electromagnetic fields in Perthes disease: report of a pilot study.

Harrison MH, Bassett CA.

A pilot study of pulsed electromagnetic fields (PEMFs) in the treatment of 10 older children with unilateral Perthes disease of the hip is reported. Patients were allowed to walk using crutches, with the affected hip splinted by the Birmingham containment orthosis during the day. For 10 h during the night the affected hip was exposed to PEMFs delivered via a pair of coils, mounted anterior and posterior to the hip joint on a plastic abduction orthosis. Splintage time of this group was compared with that of 72 patients selected at random from a historical control group of 200 patients. The 72 patients and the 10 children were assigned to early or late groups depending on the radiologic evolution of the disease when treatment commenced. The group of 10 children showed an overall reduction of time in all splintage of 32% in early cases (to 12.8 months) and 18% in late cases (to 13.5 months). No untoward effects were detected during the 2 years that these children have been under observation. In view of the apparent safety of PEMFs and their effects in this limited population of older patients with advanced Perthes disease, a double-blind study in younger patients with earlier lesions seems to be justified.

J Pediatr Orthop. 1984 Sep;4(5):579-84.

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