Nerve Stimulation Electrodes Research Articles

Clinical Effects of Implantable Sacral Neuromodulation Combined with Floating Needle Reperfusion in the Treatment of Patients with Functional Defecation Disorders

Objective: To investigate the clinical effect of implantable sacral neuromodulation combined with floating needle reperfusion in treating patients with functional defecation disorder. Methods: 40 eligible constipated patients with defecation disorder were screened according to the criteria of Rome IV for chronic constipation, and were divided into 20 cases each in the control group and the study group according to the random number table method. The control group was given oral lactulose combined with mosapride treatment, and the study group was given implantation of sacral nerve stimulation electrodes and floating needle reperfusion treatment. The clinical symptoms, visual analog scale (VAS) score, Wexner score for constipation, quality of life score, anorectal manometry, adverse reactions, and complications were observed in both groups. Results: After treatment, the median number of voluntary feces per week and the median number of days of voluntary feces per week in the study group were higher than those in the control group, and the median duration of defecation was lower than that in the control group (P < 0.05); the median VAS score of the study group was significantly higher than that of the control group (P < 0.05); the constipation Wexner score of the study group was significantly lower than that of the control group (P < 0.001); the quality of life scores of the study group were overall better than those of the control group (P < 0.05); the anal resting pressure, anal residual pressure, and rectal propulsion of the study group were significantly better than those of the control group (P < 0.05); liquefaction of the incision occurred in only one patient during treatment in the study group, which was healed after changing the medication and did not have any serious complications, and two patients in the control group had abdominal pain, and there was no significant difference between the two groups (P > 0.05). Conclusion: In the treatment of patients with functional defecation disorder, implantable sacral neuromodulation combined with floating needle reperfusion therapy can effectively improve the clinical symptoms and quality of life of patients.

The impact of chemical functionalization of carbon nanotubes on the electrochemical performance of carbon fiber/pyrocarbon/carbon nanotube composites as potential materials for electrodes for nerve cell stimulation

In this work, we propose a new carbon–carbon (C–C) composites as a potential materials for electrodes for neural stimulation in neurodegenerative disorders. The C–C composites were made via chemical vapour deposition (CVD) synthesis of pyrocarbon on carbon fibers, with subsequent thermal spray deposition of carbon nanotubes (CNT). Different CNT types were tested to evaluate their impact on electrochemical and biological performance. Materials were analyzed for microstructure, surface chemistry, and electrochemical properties, then tested using SH-SY5Y neuroblastoma cells for biological assessment. TheC–C composites coated with a hydroxy-terminated CNT demonstrated significantly enhanced electrochemical properties, inparticular increased cathodal charge capacity upto12.51mCcm−2, a wide safe potential window of −1.53 to 1.26 V, and decreased impedance, and cut-off frequency (fcut-off = 0.16 kHz). No acute negative biological responses of the materials were detected after 48 h of exposition. Such properties significantly outperform the properties of platinum, which is the basic element of platinum electrodes, demonstrating the excellent performance of the obtained composites and showing it may constitute the basic element of carbon electrodes for nerve stimulation in the future. Our work presents the method for obtaining biologically inert carbon composite micro-electrodes which can potentially be adapted to neural stimulation.

A Zero-Voltage-Writing Artificial Nervous System Based on Biosensor Integrated on Ferroelectric Tunnel Junction.

The artificial nervous system proves the great potential for the emulation of complex neural signal transduction. However, a more bionic system design for bio-signal transduction still lags behind that of physical signals, and relies on additional external sources. Here, this work presents a zero-voltage-writing artificial nervous system (ZANS) that integrates a bio-source-sensing device (BSSD) for ion-based sensing and power generation with a hafnium-zirconium oxide-ferroelectric tunnel junction (HZO-FTJ) for the continuously adjustable resistance state. The BSSD can use ion bio-source as both perception and energy source, and then output voltage signals varied with the change of ion concentrations to the HZO-FTJ, which completes the zero-voltage-writing neuromorphic bio-signal modulation. In view of in/ex vivo biocompatibility, this work shows the precise muscle control of a rabbit leg by integrating the ZANS with a flexible nerve stimulation electrode. The independence on external source enhances the application potential of ZANS in robotics and prosthetics.

Effect of electrode attachment location for transcutaneous electrical nerve stimulation for pain relief in lumbar vertebral body fractures.

[Purpose] This study aimed to investigate the effect of the location of electrode attachment in transcutaneous electrical nerve stimulation on pain relief in patients with lumbar vertebral body fractures. [Participants and Methods] This study included 59 patients with lumbar vertebral body fractures, who were randomly assigned to receive transcutaneous electrical nerve stimulation to the lumbar region, lower limbs, or upper limbs, or no treatment, over a 4-week period. Pain, activities of daily living, and pain catastrophizing were assessed. [Results] Compared with the control group, transcutaneous electrical nerve stimulation to the lumbar region or lower limbs significantly reduced pain levels in the first 2 weeks. Although, activities of daily living and pain catastrophizing improved over time, no significant differences were observed between the groups. [Conclusion] Transcutaneous electrical nerve stimulation provides pain relief to patients during the early stages of lumbar vertebral body fractures. However, it had no effect on the activities of daily living, pain catastrophizing, or long-term pain-relief. For lumbar vertebral body fracture pain relief, transcutaneous electrical nerve stimulation electrodes should be attached to the lumbar region or lower limbs.

Vagus Nerve Stimulation Electrode Impedance Over Time in Children With Lennox-Gastaut Syndrome

ObjectiveThis manuscript describes the behavior of impedance of vagus nerve stimulation (VNS) electrode over time in a cohort of children with Lennox-Gastaut syndrome. Materials and MethodsNineteen consecutive pediatric patients with Lennox-Gastaut syndrome submitted to VNS were studied. All patients had at least four years of follow-up. Serial impedance measurements were carried out during every out-patient visit. A baseline value was obtained one month after surgery, before generator activation and yearly values were recorded for the next four years. Outcome regarding seizures was obtained through analysis of standardized seizure diaries filled out by the patient, relatives, or caregivers. ResultsThere were 12 boys. Age ranged from four to 14 years (mean = 7.2). Mean impedance value was 2635 Ω at baseline, 2576 Ω after one year, 2418 Ω after two years, 2340 Ω after three years, and 2241 Ω after four years. There was a mean impedance decrease of 17% after four years. This decrease was statistically significant compared with baseline by the second year of follow-up: p = 0.342 after one year, p = 0.007 after two years, p = 0.001 after three years, and p = 0.001 after four years. There was no significant relationship between impedance values and seizure outcome at any time point. ConclusionsVNS electrode impedance significantly decreased during long-term follow-up in children with Lennox-Gastaut syndrome. To our knowledge, this is the first report on such findings regarding VNS in the literature. These findings suggest that the electrode/nerve interface is stable during long-term follow-up of VNS therapy and that this preserved anatomical relationship might be related to our ability to safely stimulate and review/explant the system whenever needed.

Self-Closing Stretchable Cuff Electrodes for Peripheral Nerve Stimulation and Electromyographic Signal Recording

The cuff electrode can be wrapped in the columnar or tubular biological tissue for physiological signal detection or stimulation regulation. The reliable and non-excessive interfaces between the electrode and complex tissue are critical. Here, we propose a self-closing stretchable cuff electrode, which is able to self-close onto the bundles of tissues after dropping water. The curliness is realized by the mechanical stress mismatch between different layers of the elastic substrate. The material of the substrate can be selected to match the modulus of the target tissue to achieve minimal constraint on the tissue. Moreover, the self-closing structure keeps the cuff electrode free from any extra mechanical locking structure. For in vivo testing, both sciatic nerve stimulation to drive muscles and electromyographic signal monitoring around a rat's extensor digitorum longus for 1 month prove that our proposed electrode conforms well to the curved surface of biological tissue.

Towards an artificial peripheral nerve: Liquid metal-based fluidic cuff electrodes for long-term nerve stimulation and recording

Nerve cuff electrodes have been used for decades as peripheral nerve interfacing devices in the fields of neural science, neural disease, and brain-machine interfacing. The currently-used cuff electrode is commonly based on rigid materials whose flexibility and tensile properties are far different from those of biological nervous tissue. Herein, a fluidic cuff electrode using a gallium-based liquid metal (LM) conductor is developed as a prototype artificial peripheral nerve. The results indicate that the LM cuff electrode has high flexibility and maintains outstanding conductivity. After implanted and connected to the sciatic nerve, the LM electrodes within the freely moving rats' bodies survive repeated body stretching and retain their long-term effectiveness in transmitting sciatic nerve signals with a high signal-to-noise ratio during two-week experiments. The LM electrodes are also proven capable of transmitting neural stimuli to the peripheral nerve on a long-term basis by triggering clear event-related potentials (ERPs) in terms of both the cortical potential and sciatic signal. These tests demonstrate that the LM electrodes meet the requirements of peripheral nerve signal recording and stimulation for long-term implantation, and have the potential to become a new generation of artificial peripheral nerve devices to interface with, supplement, or even enhance and replace the real peripheral nerve.

Integrated, Transparent Silicon Carbide Electronics and Sensors for Radio Frequency Biomedical Therapy.

The integration of micro- and nanoelectronics into or onto biomedical devices can facilitate advanced diagnostics and treatments of digestive disorders, cardiovascular diseases, and cancers. Recent developments in gastrointestinal endoscopy and balloon catheter technologies introduce promising paths for minimally invasive surgeries to treat these diseases. However, current therapeutic endoscopy systems fail to meet requirements in multifunctionality, biocompatibility, and safety, particularly when integrated with bioelectronic devices. Here, we report materials, device designs, and assembly schemes for transparent and stable cubic silicon carbide (3C-SiC)-based bioelectronic systems that facilitate tissue ablation, with the capability for integration onto the tips of endoscopes. The excellent optical transparency of SiC-on-glass (SoG) allows for direct observation of areas of interest, with superior electronic functionalities that enable multiple biological sensing and stimulation capabilities to assist in electrical-based ablation procedures. Experimental studies on phantom, vegetable, and animal tissues demonstrated relatively short treatment times and low electric field required for effective lesion removal using our SoG bioelectronic system. In vivo experiments on an animal model were conducted to explore the versatility of SoG electrodes for peripheral nerve stimulation, showing an exciting possibility for the therapy of neural disorders through electrical excitation. The multifunctional features of SoG integrated devices indicate their high potential for minimally invasive, cost-effective, and outcome-enhanced surgical tools, across a wide range of biomedical applications.

Characterization of a Temporary Peripheral Nerve Stimulation Electrode Utilizing a Bioabsorbable Suture Substrate.

Electrical stimulation after peripheral nerve injury (PNI) has the potential to promote more rapid and complete recovery of damaged fiber tracts. While permanently implanted devices are commonly used to treat chronic or persistent conditions, they are not ideal solutions for transient medical therapies due to high costs, increased risk of surgical injury, irritation, infection, and persistent inflammation at the site of the implant. Furthermore, removal of temporary leads placed on or around peripheral nerves may have unacceptable risk for nerve injury, which is counterproductive in developing therapies for PNI treatment. Transient devices which provide effective clinical stimulation while being capable of harmless bioabsorption may overcome key challenges in these areas. However, current bioabsorbable devices are limited in their robustness and require complex fabrication strategies and novel materials which may complicate their clinical translation pathway. In this study, we present a simple bioabsorbable / biodegradable electrode fabricated by modifying standard absorbable sutures, and we present data characterizing our prototype's stability in vitro and in vivo.

Development of a Novel Technique for the Measurement of Neuromuscular Junction Functionality in Isotonic Conditions

IntroductionThe neuromuscular junction (NMJ) is a chemical synapse responsible for converting electrical pulses generated by the motor neuron into electrical activity in muscle fibers, and is severely impaired in various diseases, such as Amyotrophic Lateral Sclerosis (ALS). Here, we proposed a novel technique to measure, for the first time, NMJ functionality in isotonic conditions, which better reflect muscle physiological activity.MethodsWe employed the in-situ testing technique, studied a proper placing of two pairs of wire electrodes for nerve and muscle stimulation, developed an extensive testing protocol, and proposed a novel parameter, the Isotonic Neurotransmission Failure (INF), to properly capture the impairments in neurotransmission during isotonic fatigue. We employed wild-type mice to assess the feasibility of the proposed technique, and the ALS model SOD1G93A mice to demonstrate the validity of the INF.ResultsResults confirmed the measurement accuracy in term of average value and coefficient of variation of the parameters measured through nerve stimulation in comparison with the corresponding values obtained for membrane stimulation. The INF values computed for the SOD1G93A tibialis anterior muscles pointed out an impairment of ALS mice during the isotonic fatigue test, whereas, as expected, their resistance to fatigue was higher.ConclusionsIn this work we devised a novel technique and a new parameter for a deep assessment of NMJ functionality in isotonic conditions, including fatigue, which is the most crucial condition for the neuronal signal transmission. This technique may be applied to other animal models, to unravel the mechanisms behind muscle-nerve impairments in other neurodegenerative pathologies.

The effectiveness of different electrical nerve stimulation protocols for treating adults with non-neurogenic overactive bladder: a systematic review and meta-analysis.

Electrical nerve stimulation is a widely used treatment for overactive bladder but there is no consensus regarding the best placement of electrodes or protocols. We hypothesised that some non-implanted neurostimulation protocols would be more effective compared to others for treating urinary symptoms and improving quality of life among adults diagnosed with non-neurogenic overactive bladder. A systematic review and meta-analyses of randomized clinical trials were performed in five electronic databases: PubMed/MEDLINE, Lilacs, CINAHL, Web of Science, and PEDro. The main outcome was urinary symptoms-frequency, nocturia, and urgency-and the secondary outcome quality of life. Some protocol characteristics were extracted, e.g., frequency, pulse width, intensity, intervention time, and electrode placement. Nine randomized controlled trials were included. Tibial neurostimulation showed better results than sacral neurostimulation for urge incontinence (mean difference = 1.25 episodes, 95% CI, 0.12-2.38, n = 73). On the pooled analysis, the different neurostimulation protocols-intravaginal, percutaneous tibial, and transcutaneous tibial nerve stimulation-demonstrated similar results for urinary frequency, nocturia, and urgency as well as quality of life. In general, effect sizes from meta-analyses were low to moderate. The best reported parameters for percutaneous tibial nerve stimulation were 20-Hz frequency and 200-μs width, once a week. There was evidence that tibial neurostimulation is more effective than sacral neurostimulation for urge incontinence symptoms among patients with non-neurogenic overactive bladder. Overall, there was no superiority of an electrical nerve stimulation electrode placement and protocol over others considering urinary symptoms and quality of life. Further studies with three-arm trials are necessary. This study was registered at PROSPERO: CRD4201810071.

Computational Modeling of an Endovascular Peripheral Nerve Interface.

Implantable neuromodulation devices that interface with the peripheral nervous system are a promising approach to restore functions lost to nerve damage. Existing nerve stimulation electrodes require direct contact with the target nerve and are associated with mechanical nerve damage and fibrous tissue encapsulation. Endovascularly delivered electrode arrays may provide a less invasive solution. Using a hybrid tissue conductor-neuron model and computational simulations, this study demonstrates the feasibility of delivering electrical stimulation of a peripheral nerve from a blood vessel in the vicinity of the target and predicts that the stimulation intensity required strongly depends on nerve-vessel distance and relative orientation, which are important factors to consider when screening candidate blood vessels for electrode implantation.

Design and Analysis of Electrodes for Electrostimulation (TENS) Using the Technique of Film Printing and Embroidery in Textiles.

This article describes the development of transcutaneous nerve stimulating electrodes (TENS) by means of electrically conductive ink and conductive yarn. The scope of work covered a selection of three types of knitwear with a similar surface weight with different raw material composition. Stimulating electrodes were made by means of film printing and machine embroidery. The electrodes were verified after friction tests, washing, and mechanical deformation. Each process was followed by a check of the resistive properties and assessment of the sensations in order to evaluate their performance. Tests of the surface resistance of research materials confirmed the possibility of preparing textile electrodes for electrostimulation with the use of the film-printing technique and machine embroidery. Resistance of the electrodes made on all types of substrates ranged from approximately 1.00 × 10−2 Ω to around 2.00 × 102 Ω, while the electrodes are commercially available at the level of approximately 3.5 × 105 Ω. This paper underpins the validation of the conclusion that operational processes do not adversely affect the functioning of the developed textile electrodes.

Stretchable gold nanowire-based cuff electrodes for low-voltage peripheral nerve stimulation

Objective. Electrical stimulation of the peripheral nervous system (PNS) can treat various diseases and disorders, including the healing process after nerve injury. A major challenge when designing electrodes for PNS stimulation is the mechanical mismatch between the nerve and the device, which can lead to non-conformal contact, tissue damage and inefficient stimulation due to current leakage. Soft and stretchable cuff electrodes promise to tackle these challenges but often have limited performance and rely on unconventional materials. The aim of this study is to develop a high performance soft and stretchable cuff electrode based on inert materials for low-voltage nerve stimulation. Approach. We developed 50 µm thick stretchable cuff electrodes based on silicone rubber, gold nanowire conductors and platinum coated nanowire electrodes. The electrode performance was characterized under strain cycling to assess the durability of the electrodes. The stimulation capability of the cuff electrodes was evaluated in an in vivo sciatic nerve rat model by measuring the electromyography response to various stimulation pulses. Main results. The stretchable cuff electrodes showed excellent stability for 50% strain cycling and one million stimulation pulses. Saturated homogeneous stimulation of the sciatic nerve was achieved at only 200 mV due to the excellent conformability of the electrodes, the low conductor resistance (0.3 Ohm sq−1), and the low electrode impedance. Significance. The developed stretchable cuff electrode combines favourable mechanical properties and good electrode performance with inert and stable materials, making it ideal for low power supply applications within bioelectronic medicine.

Cadaveric Model Simulations for Training in Ultrasound-Guided Percutaneous Placement of a Novel Peripheral Nerve Stimulation Electrode

Peripheral nerve stimulation (PNS) electrodes are used to treat intractable painful conditions involving peripheral nerves. Methods for performing PNS continue to evolve, from open surgical to minimally invasive placement of electrodes. A PNS system consisting of subcutaneously implanted leads with an integrated anchor and electrodes, and an external pulse generator to produce peripheral neuromodulation, is now available for use in the clinical setting. This novel system allows either surgical or percutaneous lead positioning, and avoids the use of long leads or extensions crossing the joints, which are exposed to mechanical stress and damage. To identify methods for successfully inserting these electrodes, we investigated if a cadaver model could be an effective educational tool for teaching PNS electrode placement using ultrasound guidance. Six cadavers were studied in an attempt to find an ideal approach for ultrasound-guided electrode placement into the upper and lower extremities and cervical spine, and to describe the unique anatomy of the peripheral nerves relative to percutaneous stimulation-electrode placement. The use of cadaveric model simulations offers opportunities to practice percutaneous placement of PNS electrodes under stress-free conditions without patient discomfort, to acquire skill and confidence in performing these surgical approaches. Ultrasound-guided percutaneous placement of PNS electrodes should be learned in a simulation laboratory before such placement is performed in actual patients.

The feasibility of vagal nerve stimulation revision surgery and surgical techniques: a retrospective review

Background With the large number of VNS implants performed worldwide, the need for removal or replacement of the device in selected cases is emerging, this removal or replacement of VNS can be challenging. Aims/objective To describe the feasibility and safety of revising vagal nerve stimulation surgery in terms of the indications, surgical techniques, and outcomes. Materials and methods A retrospective study, a series of eight cases with VNS implants that needed revision surgery have been reviewed, four devices were completely removed and four were only revised. The revision surgery was performed after a range of 7 months to 6 years, due to different reasons. Initial surgeries and revisions were performed at the otolaryngology department in a major tertiary center. Conclusions and significance We concluded that the previously implanted vagal nerve stimulation electrodes can be completely removed without any significant sequelae on the nerve. It may also be re-implanted safely at the previously used segment of the vagus nerve with a similar outcome in seizure control as the initial implantation.

Hydrogel-based electrodes for selective cervical vagus nerve stimulation

Objective. Electrical vagus nerve stimulation (VNS) has the potential to treat a wide variety of diseases by modulating afferent and efferent communication to the heart, lungs, esophagus, stomach, and intestines. Although distal vagal nerve branches, close to end organs, could provide a selective therapeutic approach, these locations are often surgically inaccessible. In contrast, the cervical vagus nerve has been targeted for decades using surgically implantable helix electrodes to treat epileptic seizures and depression; however, to date, clinical implementation of VNS has relied on an electrode with contacts that fully wrap around the nerve, producing non-selective activation of the entire nerve. Here we demonstrate selective cervical VNS using cuff electrodes with multiple contacts around the nerve circumference to target different functional pathways. Approach. These flexible probes were adjusted to the diameter of the nerve using an adhesive hydrogel wrap to create a robust electrode interface. Our approach was verified in a rat model by demonstrating that cervical VNS produces neural activity in the abdominal vagus nerve while limiting effects on the cardiovascular system (i.e. changes in heart rate or blood pressure). Main results. This study demonstrates the potential for selective cervical VNS as a therapeutic approach for modulating distal nerve branches while reducing off target effects. Significance. This methodology could potentially be refined to treat gastrointestinal, metabolic, inflammatory, cardiovascular, and respiratory diseases amenable to vagal neuromodulatory control.

The effect of electrotherapy on traumatic lesions of the sciatic nerve: A review of evidenced-based physiotherapy practice

Damage to the sciatic nerve is rare but causes pain that is not easily relieved, thus often necessitating hospitalization. The most common causes of injury are hip surgery, local injections, amputation and hip fracture. This review aims to describe research data on the efficacy of electrotherapy applications in cases of sciatic nerve injury. The GoogleScholar and PubMed databases were searched in English with the following keywords: electrotherapy, sciaticinjury, physiotherapy, efficacy. Both clinical trials and systematic reviews were included in the review. This review included seven clinical trials and two systematic reviews on the efficacy of various electrotherapy methods. The results of the review showed that electrotherapy can help improve the pain resulting from damage to the sciatic nerve. According to the results of this review, the application of electro acupuncture (EA), Percutaneous Electrical Nerve Stimulation (PENS), Transcutaneous Electrical Nerve Stimulation (TENS) and Medium-Frequency Electrotherapy (MFE) is considered to have a positive effect, although the results of the studies in many cases appear ambiguous. By comparison, EA is considered more efficient. PENS was significantly more effective than TENS in improving physical activity, pain and sleep quality, and post-operative function. New methods, such as the application of Peripheral Nerve Stimulation (PNS) electrodes with the use of ultrasound, need to be better evaluated in the coming years, but they look very promising.

Thirty-Six-Month Follow-up of Diaphragm Pacing with Phrenic Nerve Stimulation for Ventilator Dependence in Traumatic Tetraplegia: The Way Forward for Spinal Cord Injury Rehabilitation in a Developing Country.

Respiratory failure and chronic ventilator dependence in tetraplegics following cervical injuries located high on the spine (C1–C3) constitute significant challenges in the rehabilitation of patients given the occurrence of repeated hospitalizations and an ever-increasing financial burden. A 30-year-old man presented with posttraumatic tetraplegia following an unstable injury at the C1–C2 level with cord compression; he was managed by posterior stabilization and decompression followed by ventilator dependence and no rehabilitation until 6 months postinjury. We implanted phrenic nerve stimulator electrodes bilaterally for indirect diaphragm pacing by an implantable pulse generator that allowed for weaning from mechanical ventilation and spontaneous ventilator-free breathing at 20 weeks post-implantation and which facilitated post-tetraplegia rehabilitation. At 36 months after implantation, the patient is ventilator-free without any procedure-related complications or respiratory infections. Diaphragm pacing with phrenic nerve stimulation may be a way forward for ventilator-dependent tetraplegics in developing countries to pursue effective rehabilitation and improved quality of life.

Preparation of Peripheral Nerve Stimulation Electrodes for Chronic Implantation in Rats

Preparation of Peripheral Nerve Stimulation Electrodes for Chronic Implantation in Rats