Outcomes of surgical resection and vagus nerve stimulation in patients with medically refractory epilepsy and glutamic acid decarboxylase 65 antibody positivity.

Epilepsy associated with high-titer glutamic acid decarboxylase 65 (GAD65) IgG is often refractory to immunotherapies and antiseizure medication. This study sought to determine the efficacy of vagus nerve stimulation (VNS) and surgical resection in patients with drug-resistant epilepsy associated with GAD65-IgG. We retrospectively identified 15 patients with drug-resistant epilepsy and high serum GAD65 antibody titers (>20 nmol·L-1) who underwent VNS implantation (n = 6), surgical resection (n = 7), or both (n = 2). A responder to VNS was defined as someone with a ≥50% reduction in seizure frequency, and a favorable surgical outcome was defined as Engel I-II. Of the eight patients who underwent VNS implantation, three (37.5%) were initially responders, but this was not sustained in two. Of the nine patients who underwent surgical resection, three (33.3%) had a favorable outcome; however, only one patient was seizure-free at last follow-up. Pathology was available in six patients, and only one had evidence of inflammation; this patient had seizure onset 1 year prior to surgery. Favorable seizure outcome correlated with older age at time of resective surgery, with a trend favoring later age of seizure onset. Taken together, surgical resection and VNS implantation may have limited efficacy in this patient population but can be considered in carefully selected cases.

How we measure hypoglossal nerve stimulator outcome matters: titration versus single amplitude efficacy sleep studies.

STUDY OBJECTIVES: Hypoglossal nerve stimulation (HGNS) is a common treatment for obstructive sleep apnea (OSA). Objective assessment of HGNS efficacy measures apnea-hypopnea index (AHI) by multi-amplitude titration polysomnography (tPSG) and/or a single amplitude efficacy sleep study (eHST). Both tests have been used to determine efficacy despite significantly different protocols. This project's aim was to determine differences in objective outcomes in HGNS patients who underwent both tPSG and eHST post-operatively. METHODS: Data from 379 consecutive HGNS patients were retrospectively reviewed. Inclusion requirements were a pre-operative sleep study, a post-operative tPSG, and then an eHST, which at our institution is a type 3 home study. AHI mean and differences were calculated. Wilcoxon rank sum tests were used to analyze differences between tPSG and eHST. Sher15 criteria (post-operative AHI≤15 events/hour and ≥50% reduction from baseline) was calculated and compared by χ2 tests. RESULTS: Ultimately 61 patients met inclusion criteria with an average pre-operative AHI=33.2. When comparing the subject's tPSG versus eHST, tPSG AHI was significantly lower (AHI=8.8 versus AHI=17.6; respectively, p<0.001). There was also a difference in the percentage of patients that met Sher15 criteria when using tPSG (80.3%) versus eHST AHI (45.9%). CONCLUSIONS: HGNS patient's postoperative tPSG AHI was significantly lower than their eHST outcome. This work highlights the importance of reporting the type of post-operative study used in evaluating HGNS efficacy and the need for single amplitude, full-night studies to assess HGNS efficacy more accurately.

CO2 laser lingual tonsil reduction as a treatment for tongue discomfort during hypoglossal nerve stimulation: a case report.

STUDY OBJECTIVES: The purpose of this investigation is to demonstrate a multimodality approach to the surgical management of obstructive sleep apnea. Hypoglossal nerve stimulator (HGNS) implantation has been a lifechanging potion for many obstructive sleep apnea patients. When activated it produces tongue protrusion via electrical stimulation of the hypoglossal nerve. This advances the lingual tonsil, making the pharynx diameter greater. Unfortunately, for some patients the electrical stimulation required is too high and awakens the patient. METHODS: Case report. RESULTS: In this case the patient's fragmented sleep is not improved with the HGNS. Here we present a case where HGNS and CO2 laser lingual tonsil reduction are used in conjunction to reduce the HGNS setting required for airway patency, thereby allowing the patient to sleep through the night. CONCLUSIONS: For those patients who are unable to tolerate hypoglossal nerve stimulator settings, a combined approach with lingual tonsil reduction may be an alternative.

Atypical refractory occipital neuralgia treated with a unilateral dual-lead occipital nerve stimulator: a case report.

Aim: To describe the successful treatment of atypical occipital neuralgia (ON) using a unilateral dual-lead occipital nerve stimulator.Setting: Outpatient clinic/operating room.Patient: A 53-year-old male with atypical ON.Case description: Patient was previously diagnosed with treatment-refractory left-sided trigeminal neuralgia with atypical occipital distribution. On presentation, his symptoms were consistent with ON with distribution to the left fronto-orbital area. He received a left-sided nerve stimulator implant targeting both the greater and lesser occipital nerves.Results: Patient reported pain relief from a numerical rating scale 10/10 to 3-4/10.Conclusion: ON with referred ipsilateral trigeminal distribution should be considered when patients present with simultaneous facial and occipital pain. Further, a dual-lead unilateral stimulator approach may be a viable treatment.

Atypical, persistent inflammation to the left occipital nerve treated with a neuromodulator: a case reportAim: To describe the successful treatment of atypical headache using a one-sided nerve stimulator.Setting: Outpatient clinic/operating room.Patient: A 53-year-old male with atypical headache.Case description: Patient was previously diagnosed with left-sided chronic facial pain with pain to the back of the head. He previously failed to improve with medication and underwent Botox injections and several surgical operations targeting the nerves responsible for his pain symptoms with no improvement. He recently underwent a nerve-stimulating device trial, designed to alter the activity levels of the targeted nerve, that targeted a nerve in the back of his head. This significantly improved his pain and he ultimately presented for an official stimulator implant. Upon presentation, his symptoms were consistent with left-sided headache to the back of the head with distribution to the left eye area.Results: Patient reported significant pain relief from 10/10 to a 3-4/10, with a 10 representing the worst pain the patient has ever felt.Conclusion: Left-sided headache on the back of the head that can distribute to the left eye area should be a consistent thought for pain/headache practitioners. Further, this stimulator placement approach may be a viable treatment.

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.

Longitudinal Analysis of Hypoglossal Nerve Stimulator Therapy Uptitration Using Cloud-Based Usage Data.

This preliminary study investigates hypoglossal nerve stimulator (HNS) amplitude changes and usage patterns during the initial HNS uptitration period to characterize when patients achieve their therapeutic amplitude. HNS therapy amplitudes, duration, and pause times were examined across the first 4 months of implant use. Average HNS therapy amplitude increased monthly from baseline (0.7 ± 0.3 V) to the first (1.1 ± 0.3 V), second (1.4 ± 0.4 V), third (1.7 ± 0.5 V), and fourth months (1.8 ± 0.5 V) (P < .001). After 4 months, 60% had reached a therapeutic amplitude. Average therapeutic amplitude was greater for patients who did not achieve therapeutic amplitude by month 4 than for those who did (2.6 vs 1.6 V; P < .05). Body mass index, baseline apnea-hypopnea index, respiratory disturbance index, and initial HNS amplitude did not differ between the 2 groups. Predictors for therapeutic amplitude and other usage patterns require further investigation.

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.

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.

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.

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.

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.

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: Postmarket surveillance data for HGNS implanted between January 1, 2018 and March 31, 2022, were collected. Event rates and risk were calculated using the postmarket 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 3-year postimplantation 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. CITATION: Moroco AE, Wei Z, Byrd I, et al. Device-related outcomes following hypoglossal nerve stimulator implantation. J Clin Sleep Med. 2024;20(9):1497-1503.

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.

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.

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 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.

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.