Electro Stimulation Research Articles

The outcome of electrostimulation associated with the tubulization technique after sciatic nerve transection in wistar rats

Peripheral nerve injuries are common in clinical practice and are responsible for serious problems such as pain, loss of sensibility and motor, and permanent sequelae. The results of electrical stimulation are encouraging and suggest its use as an alternative treatment after nerve transaction. Objective To evaluate, in vivo, the use of electrostimulation (EE) associated with the tubulization technique on sciatic nerve injury repair in Wistar rats. Ninety male Wistar isogenic rats weighing between 200 and 300 grams were divided into three groups of 30 rats (electrostimulation associated with the tubing technique (EE), tubing suture (ST) and suture (SUT)), which were subdivided into three other groups with ten animals according to the evaluation time (three, six and nine weeks postoperative). Regeneration was assessed by walking track and histological analysis in which the determination of the area and number of Schwann cells in the nerve samples were carried out. In the functional evaluation, the group that received only one EE with 20 Hz, 3 V for one hour showed better result, statistically significant when compared to those stimulated more than once. However, when comparing the three different types of treatment at the end of nine weeks, there was statistically significant superiority in those ones treated with standard suture. Regarding the number of cells, no statistically significant result was found in none of the groups. The findings related to the nerve area, in those submitted to EE at three weeks when compared to the other groups in the same period, were significant, and in the comparison within the same group, those with suture and tube at six weeks obtained a regenerated nerve with area in a statistically significant way. The result of the functional recovery, when applied once to the EE with frequency of 20 Hz and 3 V, was similar with the studies already carried out, but the hypothesis that there would be an improvement of the results in the EE groups, with three and six weeks, was zero. Although the desired results in this study have not been obtained, it has been understood that the use of a biocompatible device for electrical stimulation of peripheral nerves and its methodology of use is an ongoing process that requires a balance between medicine and engineering and the subject must continue to be studied due to the promising results obtained so far.

Semen collection by electro-stimulation in a variety of bird orders

It is unquestinable that artificial insemination (AI) offers many benefits to avian conservation programs, but a serious impediment towards implementing AI for wild species is the development of effective techniques to consistently collect good quality ejaculates. Thus, we aimed to examine the success rate of electro-stimulation (ES) in collecting semen from 49 unconditioned males from orders Piciformes, Strigiformes, Accipitriformes, Cathartiformes, Galiformes, Anseriformes and Psittaciformes at different times of the year. Sixty out of 299 ES attempts provided ejaculates with sperm, but collection success rates varied widely (0–50%) depending on the species. Except for swans whose greater results were registered during spring-summer, males from most orders responded better to ES during winter-spring, suggesting seasonal variations on semen collection success rates. Overall, ES enabled successful semen collection from males of unproven and proven fertility under mixed pairing conditions. However, the highest success rate occurred in paired males with fertile clutches (40.6%) followed by unpaired males (22.1%), paired males without clutches (13.9%), and paired males with infertile clutches (6.8%). Behavioral responses of male birds to electrical impulses were also recorded to assess any discomfort during semen collection. Furthermore, macroscopic and microscopic analysis provided ejaculate parameters from several species, even from orders that hitherto have never been assessed for semen collection, which may serve as a starting point in the future. Altogether, these findings demonstrate the feasibility of ES in collecting semen from unpaired, unconditioned and non-imprinted males from a variety of bird orders. In the medium to long term, the use of this technique in both captive and free-ranging populations offers new perspectives to ensure genetic diversity in avian conservation programs.

Enseñanza de la MNT para el tratamiento del cólico nefrítico y su efecto analgésico con electro acupuntura

The article is about an observational, cross-sectional and prospective study carried out with patients treated in the Urology guarding department of the Dr. Ernesto Guevara de la Serna provincial hospital, with the clinical diagnosis of nephritic colic, treated with electro-acupuncture in the Medicine service Natural and Traditional from the same center. In order to transmit to the specialists and resident graduates of the Medicine career the use of Natural and Traditional Medicine, to treat this disease was taught the proper form of placement of the needle and the currents to place in the electro stimulation urologists. The study universe was selected from a sample of 139 patients, according to inclusion and exclusion criteria. The patients were treated with electro-acupuncture at the acupuncture points V23 and VB 25 using continuous wave at high frequency and low intensity. The results showed a higher frequency of this condition in patients between 31 and 40 years of age, as well as in males. The largest percent of the studied cases presented calculations with a size between 5 and 7 mm. It was demonstrated, among others, the analgesic effect of this procedure, when good results were obtained in 79.2% of the treated patients were the residents who most frequently participated in the treatments.

The evaluation of changes in peripheral neuropathy and quality-of-life using low-frequency electrostimulation in patients treated with chemotherapy for breast cancer: a study protocol

BackgroundChemotherapy-induced peripheral neuropathy (CIPN) is a progressive, enduring, and sometimes irreversible neurotoxic symptom that occurs in 30–40% of chemotherapy-treated cancer patients. CIPN negatively affects both the patient’s abilities to perform daily activities and their health-related quality of life (HRQOL) after chemotherapy treatment. Although this neuropathy has been treated with duloxetine and/or gabapentin, limited therapeutic benefits have been reported, thereby necessitating the development of an integrated approach that combines pharmacological management and complementary methods such as acupuncture and electric nerve stimulation. Therefore, this study is designed to examine the effect of a portable, low-frequency electrostimulation (ES) device on CIPN symptoms and HRQOL of female patients diagnosed with CIPN immediately after chemotherapy for breast cancer.MethodsThis study is a single-center, randomized, placebo-controlled trial with two parallel groups and a 2-week follow-up. We will enroll 80 breast cancer patients who are newly diagnosed with CIPN after chemotherapy. Duloxetine or pregabalin will be prescribed to all participants from the initial assessment. Half of the patients will be assigned into the experimental group and the other half to the control group. The CarebandR (Piomed Inc., Seoul, Korea), a wearable wristband that generates low-frequency electrostimulation, will be administered only to the experimental group. Electrostimulation will be administered on the unilateral PC6 acupoint. A numerical rating scale will be used to assess the overall intensity of CIPN symptoms. The key secondary outcome variables include patient-reported CIPN symptom distress tested by a self-rated questionnaire, physician-rated symptom severity assessed by the Total Neuropathy Score, and HRQOL.DiscussionIt is expected that the combination of a low-frequency electrostimulation device and pharmacological intervention (duloxetine or pregabalin) will produce synergistic effects in breast cancer patients with CIPN after treatment. To our knowledge, this is the first study to investigate the beneficial effect of a new integrated approach for CIPN management after breast cancer treatment. The study findings can expand our knowledge and understanding of the occurrence of CIPN and the efficacy of integrated intervention efforts to ameliorate CIPN symptoms.Trial registrationClinical Research Information Service (CRIS), Republic of Korea, ID: KCT0002357. Registered retrospectively on 13 June 2017.

A Moderate Supplementation of Native Whey Protein Promotes Better Muscle Training and Recovery Adaptations Than Standard Whey Protein - A 12-Week Electrical Stimulation and Plyometrics Training Study.

The purpose of this study was to assess if native whey protein (NW) supplementation could promote recovery and training adaptations after an electrostimulation (ES) training program combined to plyometrics training. Participants were allocated into three groups, supplemented 5 days/week, either with 15 g of carbohydrates + 15 g of NW (n = 17), 15 g of carbohydrates + 15 g of standard whey protein (SW; n = 15), or placebo (PLA; 30 g of carbohydrates; n = 10), while undergoing a 12-week ES training program of the knee extensors. Concentric power (Pmax) was evaluated before, immediately after, as well as 30 min, 60 min, 24 h, and 48 h after the 1st, 4th and last ES training session. The maximal voluntary contraction torque (MVC), twitch amplitude, anatomical cross-sectional area (CSA) and maximal voluntary activation level (VA) were measured before (T0), and after 6 (T1) and 12 weeks of training (T2). Pmax recovery kinetics differed between groups (p < 0.01). Pmax started to recover at 30 min in NW, 24 h in SW and 48 h in PLA. Training adaptations also differed between groups: MVC increased between T0 and T2 in NW (+11.8%, p < 0.001) and SW (+7.1%, p < 0.05), but not PLA. Nevertheless, the adaptation kinetics differed: MVC increased in NW and SW between T0 and T1, but an additional gain was only observed between T1 and T2 in NW. VA declined at T1 and T2 in PLA (−3.9%, p < 0.05), at T2 in SW (−3.5%, p < 0.05), and was unchanged in NW. CSA increased, but did not differ between groups. These results suggest that NW could promote a faster recovery and neuromuscular adaptations after training than SW. However, the mechanisms underlying this effect remain to be identified.

Botulinum neurotoxin-A usage and training in cervical dystonia &amp; spastic paresis: First results from the Ixcellence Network® survey

Botulinum neurotoxin-A (BoNT-A) is commonly used as first line treatment for Cervical Dystonia (CD) and Spastic Paresis (SP). The Ixcellence Network® (IN) international survey aims to describe the current situation of training and practices among physicians performing BoNT-A injections. A self-completion questionnaire, written by a multidisciplinary steering committee, was completed by experts managing patients with SP and CD, selected from the IN faculty, regarding their experience, training and confidence in different BoNT-A injection techniques and rehabilitation methods. Here we present a partial analysis of the 17 first respondents’ answers. Additional results from a database of more than 700 practitioners (IN attendees) will be available for the congress. Seventeen physicians specialized in physical medicine and rehabilitation (9/17), neurology (7/17) and neuropediatrics (1/17) completed the questionnaire. They reported a mean experience of 22 years in their field (from 14 to 30 years) and 18 years in BoNT-A injection (from 5 to 25 years). All received training prior to first injection, complete with dedicated sessions on guidance techniques: 15 on ultrasound, 11 on anatomical landmarks, 6 on electrostimulation (ES) and 7 on electromyography (EMG). In their current practice, BoNT-A injection was mostly performed without guidance or using ultrasound (16/17 respondents vs 11/17 for ES or EMG). Fifteen physicians also attended specific training on rehabilitation methods for SP (11), CD (1) or both (3). Overall, physicians who followed specific training in injection techniques or in rehabilitation reported greater self-confidence in using them. Training on injection technique and rehabilitation for SP and CD management is variable. Nevertheless, attending specific courses was associated with greater self-confidence. Moreover, physicians mainly used the techniques and methods for which they were trained. These first results highlight the relevance of training in this field.

Immediate results from biofeedback and anorectal electrostimulation in the treatment of paradoxical puborectal muscle contraction in women with obstructed defecation

ObjectiveThis study was conducted to evaluate the effects of “biofeedback” (BF), electrostimulation (ES), and of the high-fiber diet associated with behavioral therapy in women with obstructed evacuation and paradoxical puborectalis contraction and to compare the results among these three modalities. MethodThirty-one women were evaluated who fulfilled the Rome III Criteria, and with an electromanometric test positive for the presence of contraction in the evacuation maneuver. These patients were randomized into three groups: group I – conventional treatment of constipation, group II – conventional treatment of constipation associated with biofeedback and group III – conventional treatment of constipation associated with electrostimulation. At the beginning of this study and after six weeks, subjective and objective parameters of the anorectal function were evaluated using the Wexner constipation scoring system, the Bristol scale, an visual analogical scale, and anorectal electromanometry. ResultsAll patients demonstrated improvement in bowel satisfaction, stool frequency, effort and feeling of incomplete evacuation, stool-type modifications, and improvement in the quality of life. On examination, there was increased mean pressure of voluntary contraction in group III (p=0.043), decreased sensitivity threshold in group II (p=0.025) and III (p=0.012) and decreased maximum rectal capacity in group II (p=0.005). Only 19.4% (n=6) had their dynamic defecation normalized, and 80.6% (n=25) expressed clinical, non-instrumental, improvement. ConclusionThe conventional treatment of constipation, biofeedback and electrostimulation show a significant subjective improvement in symptoms of obstructed evacuation and in quality of life, regardless of the reversal of the paradoxical puborectalis contraction.

Results of treatment of patients with combined neurogenic pathology of the lower urinary tract and distal colon of the gut by hypotonic type with electromyographic control

The article presents the results of treatment of patients with combined neurogenic pathology of the lower urinary tract and distal part of the colon according to the hypotonic type with electromyographic control. The data of electromyographic studies made it possible to develop and optimize the methods of treatment depending on the tone of the neuromuscular structures of the lower urinary tract and the distal parts of the large intestine. The conservative treatment of patients of this category with the help of stimulation by electro stimulation is effective, provides a positive effect in 87.1% of cases.

Електроміографічний контроль ефективності комплексного лікування хворих з гіперактивним сечовим міхуром і гіпокінетичним тонусом детрузора та поєднаною нейрогенною патологією дистального відділу товстої кишки

The objective: was to increase the effectiveness of treatment of patients with a hyperactive bladder and hypokinetic tone of detrusor (muscle – urine ejector) and combined neurogenic pathology of the distal colon. Materials and methods. Complex diagnostics and conservative treatment of patients with hyperactive bladder and hypokinetic tone of detrusor and combined pathology of the distal colon were performed in 36 (53%) women and 32 (47%) men. The average age of women was 43.4±2.1 years, men – 39.8± .9 years. The duration of the disease in women was 19.7±1.5 months, in men – 22.4±1.8 months. Efficacy was assessed by electromyography. Results. It has been established that electromyography reflects the functional state of the urinary tract and distal parts of the colon at their combined pathology. Conservative treatment of patients of this category with the help of stimulation by electro stimulation was effective. Conclusion. Complex conservative treatment of patients with a hyperactive bladder and hypotonic tonus detrusor and combined pathology of the distal colon is effective, which is confirmed by electromyographic control according to the results of treatment. Key words: neurogenic disorders of urination, detrusor, electromyography.

Wireless electrostimulation: a new approach in combating infection?

Electrostimulation (ES), hitherto successfully employed in wound treatment, has shown potential in antimicrobial applications, suggesting its use as synergistic to or replacement of antibiotics. The differential susceptibility of pathogens and host tissue and organs to various ES modalities might allow selective use against specific infections. The use of ES is cheaper in terms of development/testing, routine application and environmental footprint. If extensive substitution of chemical compounds is achieved, the development of resistance might be reversed through negative selection. A promising setup of ES seems to be the noncontact current transfer, due to low amperage similar to innate bioelectricity, painlessness, simple logistics and low risk for treatment-caused infection.

Comparison of the spread of two different volumes of contrast medium when performing ultrasound-guided transversus abdominis plane injection in dog cadavers.

To compare, via CT imaging, the spread of different volumes of diluted iodinated contrast medium in the transversus abdominis muscle plane of dog cadavers. Prospective, randomised study. An electro stimulation or a SonoTAP needle was inserted in plane with the ultrasound beam in the fascia between the internal oblique and transversus abdominis muscles. A test dose of 1 ml of diluted contrast (30 mg/mL iohexol) was injected to confirm positioning, followed by 0 · 5 mL/kg (n=14) or 1 mL/kg (n=12) and the distribution of the fluid compared. Contrast medium was identified exclusively in the transversus abdominis plane in 19 of 26 dogs. In one dog, the contrast lay between the external and internal oblique muscles and partially in three dogs. Intraperitoneal contrast was detected in 6 of 26 dogs (23%). No significant differences were found in the dorso-ventral or cranio-caudal spread or area of distribution but a significant difference was found in the transverse spread. There was an association between poor ultrasound visualisation of the tip of the needle and intraperitoneal injection. Injection of 1 mL/kg of diluted contrast did not result in wider cranio-caudal spread in the transversus abdominis muscle plane of dog cadavers when compared with 0 · 5 mL/kg. Intraperitoneal injection is a risk and might be reduced with good needle visualisation.

Electrostimulation Training Effects on diurnal Fluctuations of Neuromuscular Performance.

This study examined the effects of electrostimulation (ES) strength training at the same time-of-day on the diurnal fluctuations of maximal voluntary isometric contractions (MVIC) and surface electromyography (EMG). 20 male performed 3 MVICs of knee extension coupled with surface EMG before and after 5 weeks of 3 ES training sessions per week. Each ES training session consisted in 45 isometric contractions. The participants were randomly assigned to either a morning (MTG, 07:00-08:00 h) or an evening (ETG, 17:00-18:00 h) training group. Both groups performed the evaluation tests at 07:00 and 17:00 h. Before ES training, MVIC was significantly higher in the evening compared to the morning for all groups, but there was no significant difference between groups for all EMG parameters. After the ES training, the diurnal variations in MVIC were blunted in the MTG and persisted in the ETG. Significant time-of-day effect was noticed for all EMG parameters but there was no group effect. The elimination of the diurnal fluctuations of MVIC and the appearance of EMG variations by training in the morning hours suggest that neural adaptations are the main source of temporal specificity of neuromuscular performance after ES strength training.

The approach to the rehabilitation of the patients presenting with central dysphagia on an individual basis

Disorder of the swallowing act occurs in 25-50% of patients in the acutephase of stroke. The presence of dysphagia in a patient notonly can develop life-threatening complications, such as aspiration pneumonia, exhaustion and dehydration, but al so significantly reduces the quality of life of patients. Thus, the correction of thes wallowing act disorders after brain damage is a quite significant challenge for neurorehabilitation. For a long time logopedic correction remained the only method of rehabilitation inneurogenic dysphagia, and now different stimulation techniques such as surface and intra pharynx electro stimulation are widely used. Evaluation of swallowing by scintigraphy indicates that each patienth as a unique pattern of disorders of the swallowing act. Depending on which elongation phase of swallowing is essential, we have developed an individualized approach to there habilitation of patients with dysphagia, which improves the efficiency of there habilitation process.

Concordance of the location of the innervation zone of the tibialis anterior muscle using voluntary and imposed contractions by electrostimulation

Background: The innervation zone (IZ) corresponds to the location of the neuromuscular junctions. Its location can be determined by using arranged surface linear electrode arrays. Typically, voluntary muscle contractions (VC) are used in this method. However, it also may be necessary to locate the IZ under clinical conditions such as spasticity, in which this type of contraction is difficult to perform. Therefore, contractions imposed by electrostimulation (ES) can be an alternative. There is little background comparing the locations of IZ obtained by two different types of contractions. Objective: Evaluate the concordance between using voluntary and imposed contractions from electrostimulation in order to determine the location of the innervation zone of the tibialis anterior muscle in healthy volunteers. Methods: The tibialis anterior (TA) muscle of sixteen volunteers (men: 8; women: 8; age: 22.1±1.4years, weight: 61.6±7.5kg, height: 167.1±7.5cm) were evaluated using a linear electrode array. The IZ of the TA muscle was located using two types of muscle contractions, voluntary (10% MVC) and imposed contractions by ES. The concordance between both conditions was evaluated using the Bland–Altman method and the concordance correlation coefficient (CCC). The analyses were applied to the absolute and relative positions to the length of an anatomical landmark frame. Results: CCC for absolute position was 0.98 (p<0.0001, 95% CI [0.98–1.00], and CCC for relative positions also was 0.98 (p<0.0001, 95% CI [0.97–1.00]). The Bland–Altman analysis for absolute data showed an average difference of −0.63mm (SD: 4.1). Whereas, for adjusted data, the average difference was −0.20% (SD: 1.2). The power of the results, based on absolute data, was 98%, whereas for relative data, 82%. Conclusion: In healthy volunteers, there was a substantially concordance between the location of the IZ of the TA muscle derived from using contractions imposed by ES and the location derived from using VC.

Application of a direct prostate transuretral electro stimulation in a complex medical treatment of prostate and seminal vesicle tuberculosis

Application of a direct prostate transuretral electro stimulation in a complex medical treatment of prostate and seminal vesicle tuberculosis

EFFECTIVENESS OF PHYSICAL THERAPY COMBINED WITH ELECTRO STIMULATION FOR PATIENTS WITH LUMBAR PART DISC HERNIATION

Background. The aim of the study was to evaluate the effectiveness of physiotherapy combined with electro stimulation, for patients with spinal disc herniation in lumbar part. Methods. The study involved 38 people, 18 men and 20 women. The average age of all subjects was 29.84 ± 4.65 years. All subjects participated in the study for eight weeks, 30–45 minutes, three times a week. They were randomly divided in to three groups: two experimental and one control group. The first experimental group (12 people) participated in physical therapy combined with electro stimulation; the second experimental group (14 people) participated in physical therapy combined with placebo (fake) electro stimulation, and the third (control) group (12 people) participated in physical therapy treatments. All groups before and after the treatment performed trunk (flexor, extensor, lateral musculature) muscular endurance tests (McGill), analogue pain scale evaluation, and SF – 36 questionnaire. Results. After eight weeks of physical therapy combined with electro stimulation average numbers of analogue pain scale results decreased statistically significantly by 2.17 ± 1.11 (p &lt; .05), trunk extensors (33.00 ± 12.78), flexors (31.67 ± 9.15) and lateral left (20.25 ± 2.80) / right (19.50 ± 3.71) musculature differences were statistically significant (p &lt; .05). Physical therapy and placebo (fake) electro stimulation group and physical therapy group did not show statistical significance for all the tests except for analogue pain scale test (1.29 ± 0.83 and 1.92 ± 1.08). Conclusion. Physical therapy combined with electro stimulation applied for eight weeks for 25–39-year-old adults suffering from lumbar part disc herniation is an effective way to enhance trunk flexors, extensors, right/left lateral muscular endurance and reducing lumbar part back pain.

Effectiveness of dorsum hand splint and electrical stimulation on hand functions in stroke subjects

Background: Upper extremity spasticity is a common clinical outcome following stroke and may be seriously debilitating condition. Regaining functions in the upper extremities is often more difficult than in lower extremities, which can seriously affect the progress of rehabilitation. Mainly, the hand and wrist synergistic spasticity limits rehabilitation outcomes and physical function. Therefore, rehabilitation process appears to be a challenge in stroke patients, mainly with upper limb synergistic spasticity Objectives: The aim of this study is to evaluate the effectiveness of the electro stimulation and the dorsum hand splint to reduce hand flexion spastic synergy and to enhance the functional activity of paretic hand. Methods and Materials – Sixty patients with hand flexion synergistic spasticity selected for this study. They randomly assigned into two groups. One group received NMES as well as hand functions activities and asked to wear a dorsum splint for 2x3/day hours for 12 weeks. The second group received traditional physical therapy, which include active assistive range of motion and hand activities. Subjects in both groups evaluated before and after 12 weeks of treatment using Wolf Motor Function Test and active ROM for the wrist and fingers. Results: The mean value for seven factors of Wolf Motor Functional Test evaluated in both groups. There was significant difference p

Implantable diamond capsules for electro stimulation and recording

Event Abstract Back to Event Implantable diamond capsules for electro stimulation and recording Kumaravelu Ganesan1, 2, David J. Garrett1, Nick Opie2 and Steven Prawer1 1 University of Melbourne, School of Physics, Australia 2 SmartStent PTY LTD, Australia Introduction: Implantable electronic devices must necessarily adhere to a very strict set of standards before they can be approved for clinical use. One of these standards is the requirement that electronically active components such as microprocessors must be encapsulated hermetically to protect the body from the toxicity of conventional electronic components and as well as to protect the components from the harsh environment inside the body which leads to accelerated device failure. This article provides an overview of an all-diamond hermetic capsule for retinal as well as cortical implants for electrostimulation and recording. Materials and Methods: Diamond Microelectrode array: Diamond microelectrode array of 3-D surface electrodes as shown in fig1a and fig 1.b was fabricated using conventional as well as unconventional fabrication techniques. The microelectrodes are nitrogen incorporated unltrananocrystalline diamond and the body is polycrystalline diamond[1]. CMOS chip integration: Lithographically defined Indium bumps and flip chip bonding technique was used to bond the CMOS processor to the electrode to make one-to-one connection. Electrical feedthrough: An active braze alloy of 95% gold was brazed in vacuum environment to form the electrical feedthrough, electrical contacts as well as the braze line for final laser welding. Laser Microwelding : Pulsed Laser welding technique was used to join the two halves together hermetically. Fig. 1. (a) Components of the diamond/gold encapsulation with high-density diamond electrode array (2) flip-chip bonded to a 256 channel stimulator application specific integrated circuit (ASIC) (1) and a diamond box with integrated feedthroughs for power and data transfer (3). The two diamond components are sealed by welding around the outer edges of the braze seam (b).[2] (c)Diamond cortical implant for recording. This is approximately half the size of the retinal implant shown in (b) and has the dimension of 2X0.7X0.3mm. A receiver Rx coil in fabricated on the diamond body. Results and Discussion: An all diamond 256 channel retinal implant was fabricated and tested successfully. A cortical recording implant is under development with the wireless power and data transfer facilities. Conclusion: A new hermetic encapsulation paradigm for a medical implant , using polycrystalline diamond, was presented. The new packaging technology uses high-conductivity gold braze feedthroughs for power and data input and a laser welded seam of Gold-ABA braze joining the diamond shell components. This work was funded in part from Australian Research Council through its Special Research Initiative (SRI) in Bionic Vision Science and Technology grant to Bionic Vision Australia (BVA); ARC Linkage grant 2015(SMARTSTENT PTY LTD)

Investigation of the inverse piezoelectric effect of trabecular bone on a micrometer length scale using synchrotron radiation

In the present paper we have investigated the impact of electro stimulation on microstructural parameters of the major constituents of bone, hydroxyapatite and collagen. Therapeutic approaches exhibit an improved healing rate under electric fields. However, the underlying mechanism is not fully understood so far. In this context one possible effect which could be responsible is the inverse piezo electric effect at bone structures. Therefore, we have carried out scanning X-ray microdiffraction experiments, i.e. we recorded X-ray diffraction data with micrometer resolution using synchrotron radiation from trabecular bone samples in order to investigate how the bone matrix reacts to an applied electric field. Different samples were investigated, where the orientation of the collagen matrix differed with respect to the applied electric field. Our experiments aimed to determine whether the inverse piezo electric effect could have a significant impact on the improved bone regeneration owing to electrostimulative therapy. Our data suggest that strain is in fact induced in bone by the collagen matrix via the inverse piezo electric effect which occurs in the presence of an adequately oriented electric field. The magnitude of the underlying strain is in a range where bone cells are able to detect it. Statement of SignificanceIn our study we report on the piezoelectric effect in bone which was already discovered and explored on a macro scale in the 1950. Clinical approaches utilize successfully electro stimulation to enhance bone healing but the exact mechanisms taking place are still a matter of debate. We have measured the stress distribution with micron resolution in trabecular bone to determine the piezo electric induced stress. Our results show that the magnitude of the induced stress is big enough to be sensed by cells and therefore, could be a trigger for bone remodeling and growth.

A mathematical framework for predicting thermal damage during bone electrostimulation

Purpose – Electric fields (EFs) are known to influence cell and tissue activity. This influence can be due to thermal or non-thermal effects. While the non-thermal effects are still matter of discussion, thermal effects might be detrimental for cell and tissue viability due to thermal damage, this fact being exploited by applications like hyperthermia and tissue ablation. The paper aims to discuss these issues. Design/methodology/approach – In this work the authors investigate the influence of thermal damage in the consolidation of bone formation during electrostimulation (ES). The authors introduce a mathematical model describing the migration of osteoprogenitor cells, the thermal variation, the thermal damage accumulation and the formation of new bone matrix in an injury (fracture) site. Findings – Numerical results are in agreement with experimental data and show that EFs more intense than 7.5 V/cm are detrimental for the viability of osteoprogenitor cells and the formation of new bone. Originality/value – The model is suitable to conduct dosimetry studies in support of other different ES techniques aimed at improving bone and soft tissues repair.