A multi-channel stimulator with an active electrode array implant for vagal-cardiac neuromodulation studies.

BACKGROUND: Implantable vagus nerve stimulation is a promising approach for restoring autonomic cardiovascular functions after heart transplantation. For successful treatment a system should have multiple electrodes to deliver precise stimulation and complex neuromodulation patterns. METHODS: This paper presents an implantable multi-channel stimulation system for vagal-cardiac neuromodulation studies in swine species. The system comprises an active electrode array implant percutaneously connected to an external wearable controller. The active electrode array implant has an integrated stimulator ASIC mounted on a ceramic substrate connected to an intraneural electrode array via micro-rivet bonding. The implant is silicone encapsulated for biocompatibility and implanted lifetime. The stimulation parameters are remotely transmitted via a Bluetooth telemetry link. RESULTS: The size of the encapsulated active electrode array implant is 8 mm × 10 mm × 3 mm. The stimulator ASIC has 10-bit current amplitude resolution and 16 independent output channels, each capable of delivering up to 550 µA stimulus current and a maximum voltage of 20 V. The active electrode array implant was subjected to in vitro accelerated lifetime testing at 70 °C for 7 days with no degradation in performance. After over 2 h continuous stimulation, the surface temperature change of the implant was less than 0.5 °C. In addition, in vivo testing on the sciatic nerve of a male Göttingen minipig demonstrated that the implant could effectively elicit an EMG response that grew progressively stronger on increasing the amplitude of the stimulation. CONCLUSIONS: The multi-channel stimulator is suitable for long term implantation. It shows potential as a useful tool in vagal-cardiac neuromodulation studies in animal models for restoring autonomic cardiovascular functions after heart transplantation.

Video-assisted thoracoscopic surgery retrieval of a migrated unilateral hypoglossal nerve stimulator sensor lead.

Obstructive sleep apnea is a common chronic condition typically treated with positive airway pressure. However, many patients have difficulty with adherence to this therapy, and for some, implantation of a hypoglossal nerve stimulator has become an option. Though device implantation is generally well-tolerated, a minority of patients will experience serious adverse events. Here we report the unusual complication of the sensor lead migrating to the costophrenic angle and invading the pleural space. Nine months after original implantation, the sensor lead malfunctioned and was found to be displaced. Initial explantation and reimplantation of a new device resulted in the inability to find a portion of the lead. Reimaging showed the missing lead at the costophrenic angle, and the patient underwent thoracoscopic removal. He resumed therapy with the new device without difficulty. This case demonstrates the ability of the lead to migrate far from the implantation site, which has rarely been reported.

Turicella otitidis hypoglossal nerve stimulator device associated infection.

71-year-old male with history of obstructive sleep apnea presented with persistent drainage from the surgical incision site over the recently implanted hypoglossal nerve stimulator. Wound cultures from device pocket identified the pathogen as Turicella otitidis. Clinical course included treatment with broad-spectrum intravenous antibiotics and device explantation. This case is the first known T. otitidis device associated infection.

Evaluating the Efficacy of a Peripheral Nerve Simulator-Guided Brachial Plexus Block in Rabbits Undergoing Orthopaedic Surgery Compared to Systemic Analgesia.

Locoregional anaesthetic techniques are invaluable for providing multimodal analgesia for painful surgical procedures. This prospective, randomised study describes a nerve stimulator-guided brachial plexus blockade (BPB) in rabbits undergoing orthopaedic surgery in comparison to systemic lidocaine. Premedication was provided with intramuscular (IM) medetomidine, fentanyl, and midazolam. Anaesthesia was induced (propofol IV) and maintained with isoflurane. Nine rabbits received a lidocaine BPB (2%; 0.3 mL kg-1), and eight received a lidocaine constant rate infusion (CRI) (2 mg kg-1 IV, followed by 100 µg kg-1 min-1). Rescue analgesia was provided with fentanyl IV. Carprofen was administered at the end of the surgery. Postoperative pain was determined using the Rabbit Grimace Scale (RGS) and a composite pain scale. Buprenorphine was administered according to the pain score for two hours after extubation. Rabbits were filmed during the first two hours to measure distance travelled and behaviours. Food intake and faeces output were compared. Every rabbit in CRI required intraoperative rescue analgesia compared to none in BPB. However, rabbits in both groups had similar pain scores, and there was no difference in the administration of postoperative analgesia. There were no significant differences in food intake or faeces production over 18 h, and no significant differences in distance travelled or behaviours examined during the first two hours. BPB seems superior for intraoperative analgesia. Postoperatively, both groups were comparable.

Efficacy of Peripheral Nerve Stimulator Guided Pectoral Nerve Block-1 and Serratus Anterior Plane Block for Post-operative Analgesia in Modified Radical Mastectomy: A Randomized Controlled Study.

BACKGROUND: Breast carcinoma is one of the most common cancers in present-day women worldwide, hence surgical intervention for the same is inevitable. General anesthesia being the preferred technique, the selection of appropriate postoperative pain management is a major concern in which superficial fascial plane chest wall blocks play a pivotal role. We aimed to prove the efficacy of peripheral nerve stimulator-guided pectoral nerve-1 (PEC 1) block and serratus anterior plane (SAP) block for postoperative analgesia in modified radical mastectomy. METHODS: This prospective randomized controlled clinical study comprised 60 females undergoing modified radical mastectomy and was randomly allocated to two groups. Group A patients received general anesthesia while, in addition to general anesthesia, group B patients received PEC 1 and SAP blocks. Postoperatively the active and passive visual analog score (VAS), duration of analgesia, cumulative requirement of rescue analgesics in the first 24 hours and associated perioperative complications were noted. All quantitative data were analyzed by student t-test and qualitative data by chi-square test using MedCalc software 12.5. RESULTS: VAS score for first 24 hours in group B was lower at rest, on pressure over the surgical site as well as on movements compared with the patients in group A with the p-value being < 0.0001 at all time intervals. Time for receiving first rescue analgesia was shorter (1.25±0.56hour vs 20.05±7.78hour, p<0.001) with the significantly higher requirement of cumulative doses of tramadol in the first 24 hours in patients belonging to group A (233.33±47.95mg vs 110±31.62 mg, p<0.001). CONCLUSION: PEC 1 and SAP blocks given under peripheral nerve stimulator guidance have a high success rate and are reliable in providing adequate postoperative analgesia for patients undergoing modified radical mastectomy.

Device-related outcomes following hypoglossal nerve stimulator implantation.

STUDY OBJECTIVES: Hypoglossal nerve stimulation (HGNS) has been widely used to treat obstructive sleep apnea in selected patients. Here we evaluate rates of revision and explant related to HGNS implantation and assess types of adverse events contributing to revision and explant. METHODS: Post-market surveillance data for HGNS implanted between January 1, 2018 and March 31, 2022, were collected. Event rates and risk were calculated using the post-market surveillance event counts and sales volume over the same period. Indications were categorized for analysis. Descriptive statistics were reported and freedom from explant or revision curves were grouped by year of implantation. RESULTS: Of the 20,881 HGNS implants assessed, rates of explant and revision within the first year were 0.723% and 1.542%, respectively. The most common indication for explant was infection (0.378%) and for revision was surgical correction (0.680%). Of the 5,820 devices with three-year post-implantation data, the rate of explant was 2.680% and of revision was 3.557%. During this same interval, elective removal (1.478%) was the most common indication, and for revisions, surgical correction (1.134%). CONCLUSIONS: The efficacy of HGNS is comparable in the real world setting to published clinical trial data. Rates of explant and revision are low, supporting a satisfactory safety profile for this technology.

Delayed vagal nerve compressive neuropathy following placement of vagal nerve stimulator: case report.

Vagal neuropathy causing vocal fold palsy is an uncommon complication of vagal nerve stimulator (VNS) placement. It may be associated with intraoperative nerve injury or with device stimulation. Here we present the first case of delayed, compressive vagal neuropathy associated with VNS coil placement which presented with progressive hoarseness and vocal cord paralysis. Coil removal and vagal neurolysis was performed to relieve the compression. Larger 3 mm VNS coils were placed for continuation of therapy. Coils with a larger inner diameter should be employed where possible to prevent this complication. The frequency of VNS-associated vagal nerve compression may warrant further investigation.

Impact of Hypoglossal Nerve Stimulation on Consumer Sleep Technology Metrics and Patient Symptoms.

OBJECTIVES: Obstructive sleep apnea (OSA) is usually assessed at discrete and infrequent timepoints. Wearable consumer sleep technologies (CST) may allow for more granular and longitudinal assessments of OSA therapy responses and OSA-related symptoms. METHODS: In this case series, we enrolled hypoglossal nerve stimulator (HGNS) patients who had an effective treatment response for an 8-week study using a wearable CST. Participants started with "HGNS-on," were randomized to turn off HGNS therapy during either week 4 or 5 ("HGNS-off"), followed by a return to therapy, "HGNS-resume." Participants completed validated symptom questionnaires assessing sleepiness, insomnia symptoms, functional status, and overall sleep health (Satisfaction, Alertness, Timing, Efficiency, and Duration, SATED) each week. CST metrics and survey scores were compared between HGNS treatment phases. Associations between CST metrics and survey scores were assessed. RESULTS: Seven participants with a total of 304 nights of CST data showed no statistically significant changes in total sleep time (TST), wake time after sleep onset, or sleep efficiency (SE) across the study periods. During HGNS-off, survey scores indicated significantly worsened OSA-related symptom scores. Two participants had significantly higher heart rate variability (HRV) during HGNS-off (by 3.3 and 6.3 ms) when compared to HGNS active therapy periods. Amongst CST metrics, SATED scores correlated with TST (r = 0.434, p < 0.0001), HRV (r = -0.486, p < 0.0001), and SE (r = 0.320, = 0.0014). In addition, FOSQ-10 scores correlated with average HR during sleep (r = -0.489, p < 0.001). CONCLUSION: A 1-week HGNS therapy withdrawal period impacted OSA-related sleep symptoms. Sleep-related metrics measured by a wearable CST correlated with symptom scores indicating potential value in the use of CSTs for longitudinal sleep-tracking in OSA patients. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:3406-3411, 2024.

Novel Implantation Technique for Thoracoabdominal Peripheral Nerve Stimulation via a Transversus Abdominal Plane Approach for Treatment of Chronic Abdominal Pain.

Background: Chronic abdominal pain (CAP) is a common and challenging to treat condition with a global prevalence of up to 25%. Despite extensive evaluation, approximately 40% of patients with CAP have an unknown diagnosis. Medications may be ineffective, and surgery is rarely indicated. Interventional treatment including sympathetic blocks, sympathetic neurolysis, and transversus abdominal plane (TAP) blocks may be an option, but their efficacy can wane over time. Neuromodulation has emerged as an option for these patients, as there is evidence of success with dorsal column spinal cord and dorsal root ganglion (DRG) stimulation. Peripheral nerve stimulation (PNS) may be an alternative option, particularly in higher risk patients or in patients for whom neuraxial access may be unsafe or too technically challenging. Thoracoabdominal nerve peripheral nerve stimulation via a TAP approach may be more specifically targeted in comparison to dorsal column or DRG stimulation. In this short report, we detail a technique that the authors have successfully used for thoracoabdominal nerve PNS via a TAP approach for management of CAP. Methods: This article describes a novel medial to lateral ultrasound guided thoracoabdominal nerve PNS via a TAP approach technique for lead placement and implantation. Results: A medial to lateral ultrasound guided TAP approach as described to successfully implant percutaneous thoracoabdominal nerve PNS leads for management of CAP. Conclusion: The thoracoabdominal nerve PNS via a TAP approach lead placement technique noted in this report has been used as a means for management of CAP utilizing peripheral neuromodulation. Here, we present a short report detailing a potential technique for PNS utilization for management of CAP. Further studies are needed to validate the safety and efficacy of this therapy modality, although the authors have found it to be a viable management option for patients with medically refractory neuropathic CAP.

Peripheral Nerve Stimulation for the Treatment of Superior Cluneal Neuralgia: A Cadaver Demonstration of a Novel Technique for Lead Placement.

Superior cluneal neuralgia (SCN) is a distinct cause of lower back and/or leg pain related to pathology of the superior cluneal nerve. When assessing a patient with low back pain (LBP), superior cluneal neuralgia is frequently misdiagnosed. The pathophysiology of SCN ranges from myofascial compression brought on by aberrant muscle tone to direct iatrogenic injury or trauma. In this technical report we will discuss the anatomy of superior cluneal nerve, superior cluneal neuralgia, current treatment modalities, and a novel approach to peripheral nerve stimulation (PNS) lead placement via a cadaver demonstration for SCN.

Treatment of the infected sacral nerve stimulator: A scoping review.

BACKGROUND: Sacral nerve stimulators (SNSs) are a widely accepted, efficacious surgical option to treat patients who have failed conservative management for overactive bladder, nonobstructive urinary retention, fecal incontinence, or pelvic pain. As with all implanted devices, there are associated risks for surgical site and implant infections. There are currently no clear published data or guidelines regarding treating such infections. AIMS: We present a scoping review aiming to examine the existing literature on the treatment approaches of infected SNSs. METHODS: A scoping review was conducted using Preferred Reporting Items for Systematic Review and Meta-Analysis. The search strategy focused on "sacral modulation," and "infection," and "explantation," and conservative management methods such as "antibiotics." A search was conducted on medical databases, and a grey literature search was performed. RESULTS: Thirty articles were included for data extraction. Articles were published between 2006 and 2022. Outcomes were reported for 7446 patients. Two hundred and seventy-four infection events were reported, giving an overall 3.7% infection rate. Most infection events were treated with explantation, although there is some discussion on the role of conservative management using oral and intravenous antibiotics in the literature. Articles also discussed considerations for future reimplantation after explantation of SNS. CONCLUSIONS: There are currently no treatment protocols in the literature to help guide whether a patient is suited to conservative or surgical management. There is future scope for developing treatment algorithms to guide clinicians for optimal treatment of infected sacral neuromodulation devices.

Stimulating Superior Cluneal Nerves via Peripheral Nerve Stimulation as a Treatment for Chronic Low Back Pain.

Low back pain (LBP) is a challenging clinical condition for both patients and physicians. It requires a comprehensive initial diagnosis to avoid missing potential causes. One less common cause is superior cluneal neuralgia (SCN), which can present with limited lumbar motion, LBP, buttock pain, or an antalgic gait. While conservative therapies are often first line for LBP, neuromodulation, such as peripheral nerve stimulation (PNS), can be considered for more refractory cases. This case report is unique in that SCN was treated with a temporary PNS system, which provided sustained analgesic benefits without the need for permanent implantation.

Treatment of Residual Palatal Collapse in Hypoglossal Nerve Stimulation Using a Palatal Device.

Hypoglossal nerve stimulation (HNS) has increasingly become an alternative therapy for obstructive sleep apnea patients with CPAP intolerance. Stimulation of the hypoglossal nerve during sleep enhances airway patency and alleviates collapse. Suboptimal responses to HNS often stem from insufficient palatal coupling and residual velar collapse. Combining palatal devices, such as Velumount®, with HNS represents a simple and cost-effective strategy to treat residual palatal collapse. Patients desiring conservative treatment for residual palatal obstruction under HNS may consider this combined approach. Laryngoscope, 134:3412-3414, 2024.

The Reciprocal Relationship between Sleep and Epilepsy.

The relationship between sleep and epilepsy is bidirectional. Certain epilepsy syndromes predominantly or exclusively manifest during sleep, with seizures frequently originating from non-rapid eye movement (NREM) sleep. Interictal epileptiform discharges observed on electroencephalograms are most likely to be activated during the deep NREM sleep stage known as N3. Conversely, epileptiform discharges, anti-seizure medications (ASMs), as well as other anti-seizure therapies can exert detrimental effects on sleep architecture. Moreover, the co-occurrence of sleep disorders has the potential to exacerbate seizure control. Understating the relationship between sleep and epilepsy is crucial for healthcare providers. Addressing and managing sleep-related problems in individuals with epilepsy can potentially contribute to improved seizure control and overall well-being. At the same time, improving seizure control can improve sleep quality and quantity, thus further improving the health of individuals with epilepsy.

Advances in the Use of Hypoglossal Nerve Stimulator in Adolescents With Down Syndrome and Persistent Obstructive Sleep Apnea-A Systematic Review.

INTRODUCTION: The Hypoglossal Nerve Stimulator (HNS) is a novel therapy that has been extensively studied in adults and more recently, it has been incorporated in children with Down Syndrome (DS) with persistent obstructive sleep apnea after adenotonsillectomy and trial of continuous positive airway pressure treatment. This systematic review article aims to examine the existing literature on HNS use in children to explore the benefits, efficacy, and parental experiences. METHODS: MEDLINE, Web of Science and EMBASE were searched to include all studies published up to March 2nd, 2023, on the topic of HNS use in pediatric population under 21 years old. RESULTS: A total of 179 studies were initially identified from which 10 articles were consistent with the inclusion criteria. Nine articles addressed outcomes after implantation of the HNS device in children with DS and 1 article explored the parental experiences. Findings were similar across studies where after implantation of HNS, there was marked improvement in polysomnographic outcomes and quality of life scores with high level of compliance. CONCLUSIONS: HNS holds promise as an effective treatment option for pediatric patients with DS and persistent OSA after AT and CPAP trials. It significantly improves sleep-disordered breathing, quality of life, and neurocognitive measures, leading to substantial and sustained benefits for these children. While the findings are encouraging, further research is needed to explore the potential of HNS in other pediatric populations without DS and to raise awareness among healthcare providers about this treatment option. Overall, HNS may offer significant long-term benefits for the overall well-being and health of pediatric patients with DS and persistent OSA.

Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea in a Patient with Cerebral Palsy.

INTRODUCTION: Obstructive sleep apnea (OSA) is common amongst patients with cerebral palsy in part due to significant hypotonia. Hypoglossal nerve stimulation (HGNS) is a novel tool used to treat sleep apnea when there is failure with CPAP. To our knowledge, the literature has not discussed HGNS as a treatment option for severe OSA in patients with cerebral palsy. METHODS: Case report and literature review. RESULTS: A 28-year-old male with cerebral palsy, neuromuscular deformity, proximal junction kyphosis, and developmental delay presented with severe obstructive sleep apnea and was intolerant to CPAP and BiPAP. After HGNS implantation, a sleep study revealed improved ventilation and oxygenation at 2.4 V; AHI decreased from baseline of 112 to 12 events per hour with only mild intermittent snoring. The patient's family reported increased utilization compared with previous CPAP use. CONCLUSION: HGNS can be a safe and effective treatment modality for OSA in this patient population. Laryngoscope, 134:2478-2479, 2024.

A surgical decision aid for occipital neuralgia with literature review and single center case series.

BACKGROUND: Occipital neuralgia (ON) is a debilitating headache disorder. Due to the rarity of this disorder and lack of high-level evidence, a clear framework for choosing the optimal surgical approach for medically refractory ON incorporating shared decision making with patients does not exist. METHODS: A literature review of studies reporting pain outcomes of patients who underwent surgical treatment for ON was performed, as well as a retrospective chart review of patients who underwent surgery for ON within our institution. RESULTS: Thirty-two articles met the inclusion criteria. A majority of the articles were retrospective case series (22/32). The mean number of patients across the studies was 34 (standard deviation (SD) 39). Among the 13 studies that reported change in pain score on 10-point scales, a study of 20 patients who had undergone C2 and/or C3 ganglionectomies reported the greatest reduction in pain intensity after surgery. The studies evaluating percutaneous ablative methods including radiofrequency ablation and cryoablation showed the smallest reduction in pain scores overall. At our institution from 2014 to 2023, 11 patients received surgical treatment for ON with a mean follow-up of 187 days (SD 426). CONCLUSION: Based on these results, the first decision aid for selecting a surgical approach to medically refractory ON is presented. The algorithm prioritizes nerve sparing followed by non-nerve sparing techniques with the incorporation of patient preference. Shared decision making is critical in the treatment of ON given the lack of clear scientific evidence regarding the superiority of a particular surgical method.

Evaluating the Clinical Performance of a Novel, Precision Oral Appliance Therapy Medical Device Made Wholly From a Medical Grade Class VI Material for the Treatment of Obstructive Sleep Apnea.

Objective The objective of this study is to evaluate the clinical performance of a novel, precision, oral appliance therapy (OAT) medical device made entirely from a US Pharmacopeia (USP) medical grade class VI qualified material for the treatment of obstructive sleep apnea (OSA). Methods This was a multi-center, single-arm, chart-based, retrospective study of 91 patients diagnosed with OSA, treated utilizing a novel, precision, OAT medical device. Performance criteria were overall efficacy (reduction of OSA events to less than 10 per hour); efficacy for patients with severe OSA (reduction of OSA events to less than 20 per hour and a 50% improvement); and compliance (the rate of continuation of treatment after at least a one-year follow-up, or, conversely, the rate of discontinuation of treatment due to material-related adverse events or side effects after one year).  Results Eighty-nine percent of all subjects diagnosed with all levels of OSA severity were successfully treated to an apnea hypopnea index ("AHI") < 10 events per hour. Ninety-eight percent of subjects diagnosed with mild to moderate OSA were successfully treated to an AHI < 10. Eighty percent of subjects with severe OSA, without screening or excluding subjects for airway collapse profile, were successfully treated to an AHI < 20 with a 50% improvement in AHI. After a minimum one-year follow-up period, 96% of patients were confirmed to remain in active treatment. No subjects were reported to discontinue treatment due to adverse events or side effects. Conclusions This novel, precision OAT medical device made from the USP Class VI qualified material demonstrated efficacy and safety for the treatment of patients with OSA.

Successful termination of persistent hiccups via combined ultrasound and nerve stimulator-guided singular phrenic nerve block: a case report and literature review.

Persistent hiccups that occur after abdominal surgery seriously affect postoperative rehabilitation. Phrenic nerve block therapy has been recommended after failure of medication or physical maneuvers. However, the phrenic nerve is often difficult to accurately identify because of its small diameter and anatomic variations. We combined ultrasound with the use of a nerve stimulator to quickly and accurately identify and block the phrenic nerve in a patient with postoperative persistent hiccups. The ongoing hiccups were immediately terminated with no adverse effects. The patient reported no recurrence during the 2-week follow-up period. We conclude that the combined use of real-time ultrasound guidance and a nerve stimulator for singular phrenic nerve block might be an effective intervention for terminating postoperative persistent hiccups, although further studies are needed to evaluate the safety and efficacy of this technique. The findings in this case suggest a potential clinical application for this technique in managing persistent hiccups, thereby contributing to improved patient care and outcomes.