Refractory Obstructive Sleep Apnea Secondary to Vagal Nerve Stimulation.

Vagal nerve stimulator (VNS) devices are commonly used as a non-pharmacologic option for improved seizure control in patients with refractory epilepsy. However, a side effect associated with VNS device placement includes sleep-disordered breathing, which is complicated by the fact that a significant minority of patients with epilepsy have sleep-disordered breathing. We describe a patient with iatrogenically worsened refractory obstructive sleep apnea (OSA) secondary to VNS device placement, which resolved upon turning off the VNS device. This case highlights the need to screen for OSA in patients who are candidates for VNS device placement, as iatrogenic sleep-disordered breathing could place the patient at risk for adverse clinical outcomes, as well as paradoxically worsen seizure control due to poor quality sleep.

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.

Depicting and defining sleep disturbed breathing associated with vagal nerve stimulation.

BACKGROUND: Vagal nerve stimulators (VNS), which have been approved for management of refractory epilepsy and depression, induce unique disturbances of breathing during sleep (SDBVNS) that are not captured well using standard criteria. The primary purpose of this retrospective study was to compare AASM definitions with alternative criteria to more accurately measure SDBVNS We also sought to assess outcome variables that may be clinically relevant and response to positive airway pressure therapy. METHODS: We analyzed the electronic medical records and comprehensive polysomnography results of all adult subjects with active VNS for epilepsy who were referred to the sleep center for suspected sleep apnea (2015-2020). We compared standard AASM criteria for defining apneas/hypopnea index (AHIAASM) with three novel scoring criteria for hypopnea according to degree of oxygen desaturation associated with VNS events: AHIVNS0 (none required); AHIVNS2 (2% required); and AHIVNS3 (3% required). RESULTS: Twenty-six subjects were included in the final analysis with 35 PSGs (14 females/12 males). The mean age was 33.6 years and mean body mass index (BMI) of 32.2 kg/m2. AHIAASM measured ≥ 15/hour in 7 (26.9%) subjects versus 21 (80.8%) by AHIVNS0; 15 (70.0%) by AHIVNS2; and 5 (19.2%) by AHIVNS3. Clinically significant hypoxemia was not present. The mean time SpO2<89% was 7 (20.8) minutes. Oximetry tracings often showed a desaturation pattern that resembled a sawfish rather than sawtooth. Arousals specifically linked to VNS activation were not elevated (2.9/hour). The baseline AHIVNS0 was 27.7/hour with a lowest AHIVNS0 on PAP of 27.9/hr. CONCLUSIONS: AASM scoring criteria significantly underestimated the degree of VNS induced respiratory disturbances. VNS events were not associated with increased arousals or significant hypoxemia. PAP therapy was an ineffective treatment in this population. This study adds to the increasing body of evidence of sleep disordered breathing related to VNS and questions the clinical significance of this finding.

Vagal nerve stimulator-associated sleep disordered breathing secondary to vagal-induced laryngospasm in pediatric populations: Case presentation and systematic review.

OBJECTIVES: Sleep disordered breathing (SDB) is a well-documented complication of vagus nerve stimulation (VNS) in the literature. Yet, a formal consensus on its management has not been established, particularly in the pediatric population. This study aims to evaluate the current literature on VNS-associated SDB in order to further characterize its presentation, pathogenesis, diagnosis, and treatment. METHODS: A literature review from 2001 to November 8, 2021 was conducted to search for studies on SDB during vagal nerve stimulation in pediatric populations. RESULTS: Of 277 studies screened, seven studies reported on pediatric patients with VNS-associated SDB. Several investigators found on polysomnogram that periods of apnea/hypopnea correlated with VNS activity. When VNS settings were lowered or turned off, symptoms would either improve or completely resolve. CONCLUSION: VNS-associated SDB is a well described complication of VNS implantation, occurring due to an obstructive process from vagal stimulation and laryngeal contraction. Diagnosis can be made via polysomnogram. Recommended treatment is through adjustment of VNS settings. However, those who are unable to tolerate this, or who have had pre-existing obstructive issues prior to VNS, should pursue other treatment options such as non-invasive positive pressure or surgery directed by DISE findings.

Pediatric vagal nerve stimulator explantation: A comprehensive literature review and tertiary care experience.

OBJECTIVE: Patients with medically-refractory epilepsy who undergo vagal nerve stimulator (VNS) implantation to reduce seizure burden sometimes require device removal. Complete explantation refers to the removal of both the generator and vagal nerve leads, and is uncommonly performed by otolaryngologists due to the perceived risk associated with lead removal. This comprehensive literature review and case series studies safety outcomes among pediatric patients undergoing complete VNS explantation. STUDY DESIGN/SETTING: Literature review and tertiary care case series. METHODS: PubMed, Embase, Web of Science, and Google Scholar were searched to identify all articles involving VNS explantation prior to January 2023. A retrospective review of pediatric patients undergoing complete VNS explantation from 2009 to 2023 at our tertiary center was also conducted. RESULTS: After screening, 36 articles were retained involving 399 patients (139 confirmed children) who underwent complete VNS explantation. 26 patients (6.5%) experienced 1+ peri/post-operative complications. These included temporary VF paresis or dysphonia (n = 14; 3.6%), permanent vocal fold (VF) paralysis/paresis (n = 6; 1.5%), internal jugular vein injury (n = 4; 1.0%), temporary dysphagia (n = 2; 0.50%), and cable-bowstring phenomenon (n = 1; 0.25%). Data from our tertiary care center revealed eight patients (6 M: 2 F) with a mean age of 11.4 ± 6.2 years. Devices were removed for clinical ineffectiveness (n = 2), infection (n = 2), lead failures (n = 2), and increased lead impedance (n = 2). Mean total length of implantation was 44.4 ± 40.3 months. Mean follow-up was 44.8 ± 35.2 months. No complications were identified. CONCLUSIONS: Complete VNS device removal in pediatric patients is technically feasible with low reported complications. Working alongside neurosurgery, otolaryngologists offer unique expertise in dissection along the vagus nerve and may thus add value to the practice of VNS surgery.

Use of monopolar cautery in patient with a vagal nerve stimulator during neuromuscular scoliosis surgery.

It is a historic and common practice while performing spine surgery on patients with a VNS has been to have the patient's neurologist turn off the VNS generator in the pre-operative anesthetic care unit and to use bipolar rather than monopolar electrocautery. Here we report a case of a 16-year-old male patient with cerebral palsy and refractory epilepsy managed with an implanted VNS who had scoliosis surgery (and subsequent hip surgery) conducted with the use of monopolar cautery. Although VNS manufacturer guidelines suggest that monopolar cautery should be avoided, perioperative care providers should consider its selective use in high-risk instances (with greater risks of morbidity and mortality due to blood loss which outweigh the risk of surgical re-insertion of a VNS) such as cardiac or major orthopedic surgery. Considering the number of patients with VNS devices presenting for major orthopedic surgery is increasing, it is important to have an approach and strategy for perioperative management of VNS devices.

A surface electrode adjacent to vagal nerve stimulator lead can aid in characterizing vagal nerve stimulator-mediated pediatric sleep-disordered breathing: a case series of 7 patients.

STUDY OBJECTIVES: The vagal nerve stimulator (VNS) is a nonpharmacological treatment for refractory epilepsy. A side effect of the VNS is sleep-disordered breathing. The purpose of this study was to demonstrate how a surface electrode placed over the VNS lead can help distinguish whether sleep-disordered breathing is due to VNS discharge. METHODS: Seven pediatric patients (aged 7.7 ± 2.2 years) with a VNS underwent a polysomnogram with an additional surface electrode on the left anterolateral neck to detect VNS discharge. The VNS-associated apnea-hypopnea index was calculated by determining the number of hypopneas and apneas occurring during VNS discharge. We evaluated the veracity of the VNS electrode by comparing signal duration and total number to those expected by programmed settings. We compared these findings to chin electromyogram signal change. RESULTS: Three patients had an obstructive pattern with VNS discharge, and 3 had an increase in respiratory rate without gas exchange abnormalities, including 1 with both patterns; 1 patient experienced no respiratory abnormalities. The mean obstructive apnea-hypopnea index was 8.2 ± 8.3 events/h. The mean VNS-associated apnea-hypopnea index was 4.8 ± 6.2 events/h and accounted for 46.9 ± 30.2% of the total obstructive apnea-hypopnea index. The additional electrode captured a statistically high percentage of expected discharges (94.7 ± 6.5%) compared to chin electromyogram (36.1 ± 35.8%; P < .05). CONCLUSIONS: We demonstrated that a surface electrode on the VNS lead can temporally coregister VNS discharges and enabled us to attribute sleep-disordered breathing to VNS stimulation in 4 patients. We propose that this sensor be standard procedure in patients with VNS undergoing polysomnogram. CITATION: Chan JHM, DelRosso LM, Ruth C, Wrede JE. A surface electrode adjacent to vagal nerve stimulator lead can aid in characterizing vagal nerve stimulator-mediated pediatric sleep-disordered breathing: a case series of 7 patients. J Clin Sleep Med. 2022;18(8):1973-1981.

Endotracheal Tube Electrode Neuromonitoring for Placement of Vagal Nerve Stimulation for Epilepsy: Intraoperative Stimulation Thresholds.

Vagal nerve stimulators (VNS) are indicated as a palliative treatment for medically refractory epilepsy. The vagus nerve may have a variable position within the carotid sheath and may be confused with a prominent ansa cervicalis. The objective of this study was to describe an intraoperative neuromonitoring technique for VNS placement and provide stimulation thresholds that may aid in the creation of stimulation protocols. A retrospective study was performed assessing 40 patients undergoing intraoperative vocal cord monitoring during vagal nerve stimulator placement surgery. Endotracheal electrodes were utilized to record vocal cord activity at various surgical time points. The stimulation thresholds were tested at the time of opening of the carotid sheath (mean 0.35 mA [range 0.08-1.00]), after full and circumferential dissection of the vagus nerve (0.34 mA [0.10-0.90]), after tenting of the vagus nerve in preparation for placement of the electrode (0.22 mA [0.06-1.20]), and after electrode placement (0.26 mA [0.05-1.20]). The vagus nerve was identified in all patients; it was located behind the common carotid artery (CCA) in two patients, on top of the internal jugular vein (IJV) in one patient, and in the typical location between the CCA and IJV in the remainder of patients. The average size of the vagus nerve was 2.9 mm [1.5-5.0]. Intraoperative vagus nerve stimulation represents a safe adjunctive tool that can help localize the nerve, particularly in the setting of varying anatomy or hazardous dissections. It may help reduce the potential for vagal trunk damage or electrode misplacement and potentially improve clinical outcomes.

Chyle leak occurring after vagal nerve stimulator implantation in a child.

Vagus nerve stimulation is a therapy indicated for some patients with medically-refractory epilepsy. Typical risks of this procedure include infection, hoarseness, vocal cord dysfunction, and hardware malfunction. Chyle leak via injury to the thoracic duct is a known complication of thoracic and head and neck surgeries-though less so in the neurosurgical literature. In severe cases, chyle leak can lead to nutritional deficiencies and immunosuppression. Management of chyle leak includes low-fat diet and pharmacological suppression of chyle production with medications such as octreotide. If leak is persistent, surgical exploration with attempted ligation of lymphatic structures is performed.

Vagal Nerve Stimulator Placement by a Vascular Surgeon.

BACKGROUND: Refractory seizure activity represents a difficult problem for both patients and practitioners. Implantation of the vagal nerve stimulator has been posited as an effective treatment for refractory seizure activity. These devices are inserted by placing leads into the carotid sheath along the vagus nerve. We evaluated a vascular surgeon's experience placing vagal nerve stimulators. METHODS: We examined all patients treated with placement of vagal nerve stimulator by a single surgeon from October 2016 to October 2018. Data collected included demographics, medical and surgical history, intraoperative variables, and complications. RESULTS: Thirty-four patients underwent placement of a vagal nerve stimulator. About 29.4% had a previous vagal nerve stimulator placed on the ipsilateral side. Intraoperative bradycardia was seen in 1 patient. Postoperative complications were identified in 5 patients, all of which were transient dysphagia or changes in voice quality which did not require intervention. There was no significant difference between patients with the previous operation and those without for developing postoperative complications (P = .138). Average blood loss was higher in patients who had undergone previous stimulator placement than those who had not (P = .0223), and the operative time was longer (P ≤ .0001). DISCUSSION: Given the anatomical location of placement, vascular surgeons may be called upon to place these devices. In our single surgeon series, we found that the placement was safe, with minimal complications. Intraoperatively, this case appears to be more difficult (with higher blood loss and longer operative time) in patients who have had previous device placement, but this does not appear to lead to increased complications.

Epilepsy Surgery in Children.

Epilepsy in children continues to present a major medical and economic burden on society. Left untreated, seizures can present the risk of sudden death and severe cognitive impairment. It is understood that primary care providers having concerns about abnormal movements or behaviors in children will make a prompt referral to a trusted pediatric neurologist. The authors present a brief introduction to seizure types, classification, and management with particular focus on what surgery for epilepsy can offer. Improved seizure control and its attendant improvements in quality of life can be achieved with timely referral and intervention.

Technology-Dependent Children.

There are a growing number of medically complex children with implanted devices. Emergency physicians with a basic knowledge of these devices can troubleshoot and fix many of the issues that may arise. Recognition of malfunction of these devices can reduce morbidity and mortality among this special population. In this article, we review common issues that may arise in children with gastrostomy tubes, central nervous system shunts, cochlear implants, and vagal nerve stimulators.

Closed-loop vagal nerve stimulation for intractable epilepsy: A single-center experience.

PURPOSE: A new class of heart-rate sensing, closed-loop vagal nerve stimulator (VNS) devices for refractory epilepsy may improve seizure control by using pre-ictal autonomic changes as an indicator for stimulation. We compared our experience with closed- versus open-loop stimulator implantation at a single institution. METHODS: We conducted a retrospective chart review of consecutive VNS implantations performed from 2004 to 2018. Bivariate and multivariable analyses were performed to compare changes in seizure frequency and clinical outcomes (Engel score) with closed- versus open-loop devices. Covariates included age, duration of seizure history, prior epilepsy surgery, depression, Lennox Gastaut Syndrome (LGS), tonic seizures, multiple seizure types, genetic etiology, and VNS settings. We examined early (9-month) and late (24-month) outcomes. RESULTS: Seventy subjects received open-loop devices, and thirty-one received closed-loop devices. At a median of 8.5 months, there was a greater reduction of seizure frequency after use of closed-loop devices (median 75% [IQR 10-89%]) versus open-loop (50% [0-78%], p < 0.05), confirmed in multivariable analysis (odds ratio 2.72 [95% CI 1.02 - 7.4]). Similarly, Engel outcomes were better after closed-loop compared to open-loop confirmed in the multivariable analysis at the early timepoint (OR 0.26 [95% CI 0.09 - 0.69]). These differences did not persist at a median of 24.5 months. CONCLUSIONS: This retrospective single-center study suggests the use of closed-loop VNS devices is associated with greater seizure reduction and more favorable clinical outcomes than open-loop devices at 9-months though not at 24-months. Expansion of this study to other centers is warranted to increase the generalizability of our study.

The Impact of COVID-19 Lockdown on People With Epilepsy and Vagal Nerve Stimulation.

Objectives: Restrictive measures adopted during the COVID-19 pandemic, in order to limit contagion, have had a severe impact on mental health. The burden of lockdown has been particularly heavy on patients with chronic neurologic diseases such as People with Epilepsy (PwE). Our survey aims to describe the struggles and needs of Drug-Resistant (DR) PwE with implanted Vagal Nerve Stimulator (VNS) during the first wave of the COVID-19 lockdown in order to find strategies that help patients cope with present or future periods of restriction. Methods: We collected answers from 30 respondents who underwent an online survey including socio-demographic and clinical information and COVID-19-related information. Depression, anxiety symptoms, and sleep quality were investigated in patients through BDI II, GAD-7, and the PSQI scale. Results: In all, 46% of our sample reported an increase in the number of seizures; the entire sample complained of epilepsy-related issues (medication availability, VSN adjustments, anxiety, sleep disturbance); one out of three participants reported major epilepsy issues felt urgent; 30% had to postpone scheduled examination. Significantly higher scores for depression and anxiety scales were found in patients who perceived seizure frequency worsening and reported major epilepsy-related issues. Conclusion: Preliminary findings showed that the first lockdown influenced the clinical and psychological status of PwE and was related to seizures worsening. The lack of medical assistance and control on VNS therapy left patients to cope with the situation without a chance to contact a specialist. We discuss how a wider implementation of telemedicine programs could facilitate remote assistance of PwE with a VNS implant.

Behavioral Management of Laryngeal Complaints Caused by Vagal Nerve Stimulation for Medically Refractory Epilepsy.

OBJECTIVES/HYPOTHESIS: This study investigated behavioral management of dysphonia and laryngeal dyspnea secondary to use of vagal nerve stimulation (VNS) in an individual with medically refractory epilepsy. STUDY DESIGN: Retrospective chart review. METHODS: Medical records from a single patient were reviewed. The patient received treatment with the speech-language pathologist (SLP) and laryngologist to observe patterns of laryngeal hyperfunction using biofeedback, and treatment with the SLP to learn to perform rescue breathing techniques, relaxation techniques, and awareness of muscle tension to aid the control of symptoms during activation. Data collected included neurology and laryngology notes. Neurology notes were used to track VNS settings, tolerance, and incidence of seizures. Laryngology notes included documentation of diagnosis, treatment, and measures of patient perception of severity (ie, Voice Handicap Index, Dyspnea Index, Cough Severity Index). RESULTS: Prior to treatment, the patient was unable to receive benefits from VNS due to severe laryngeal adverse effects, such that the device remained off for eight months postimplantation. Following treatment, the patient effectively managed laryngeal side effects and was able to tolerate increases in VNS output current, signal frequency, and duration. CONCLUSIONS: Voice therapy was effective in managing changes in vocal fold mobility and laryngeal tension. As the number of individuals receiving VNS for epilepsy and inflammatory conditions increases, the SLP and laryngologist may play a key role in interdisciplinary management of laryngeal side effects secondary to vagal nerve stimulation.

Subgroup analysis of seizure and cognitive outcome after vagal nerve stimulator implantation in children.

OBJECTIVE: Vagal nerve stimulator (VNS) implantation at an early age seems to lead to improved quality of life and cognitive outcome. The aim of this analysis is to evaluate whether specific patient or seizure characteristics might lead to better seizure control, cognitive outcome, and higher quality of life in children undergoing VNS implantation. METHODS: Primary outcome measure was reduction in seizure frequency. Secondary outcome measures were epilepsy outcome assessed by McHugh and Engel classifications, reduction in antiepileptic drugs (AED), developmental and cognitive outcome, as well as quality of life assessed through the pediatric quality of life (PEDSQL™) questionnaire and care giver impression (CGI) scale. Forty-five consecutive children undergoing VNS implantation were analyzed for the following subgroups: age (categorized to 1-2 years old, 3-5 years old, 6-12 years old, and 13-18 years old), sex, underlying cause (categorized to idiopathic, encephalitis, stroke, syndromic), duration of preoperative seizures (dichotomized to under or above 89 months, corresponding to the median of the whole cohort), and preoperative seizure frequency (dichotomized to under and above 360 seizures per month). RESULTS: Encephalitis as the underlying cause for seizures was the only variable significantly associated with higher reduction rate of seizure frequency. Patients with VNS implantation at the age of ≤ 2 years showed a strong association with better developmental and cognitive outcome, as well as quality of life. Shorter duration of preoperative seizures and higher preoperative seizure frequency showed a strong association with better developmental outcome, as well as quality of life. Engel outcome scores were significantly better in patients with epilepsy due to encephalitis (100% Engel I-III). However, patients with epilepsy due to encephalitis showed significantly higher complication rates (71.4%, p = 0.045). CONCLUSIONS: Children suffering from epilepsy due to encephalitis show higher seizure reduction rates after VNS implantation when compared with children suffering from epilepsy due to other causes. Developmental and cognitive outcomes as well as quality of life of children undergoing VNS implantation is strongly associated with shorter duration of preoperative seizures and implantation at a young age.

A case report of Vagus nerve stimulation for intractable hiccups.

INTRODUCTION: Intractable hiccups frequently result from an underlying pathology and can cause considerable illness in the patients. Initial remedies such as drinking cold water, induction of emesis, carotid sinus massage or Valsalva manoeuvre all seem to work by over stimulating the Vagus nerve. Pharmacotherapy with baclofen, gabapentin and other centrally and peripherally acting agents such as chlorpromazine and metoclopramide are reserved as second line treatment. Medical refractory cases even indulge in unconventional therapies such as hypnosis, massages and acupuncture. Surgical intervention, although undertaken very rarely, predominantly revolves around phrenic nerve crushing, blockade or pacing. A novel surgical strategy is emerging in the form of Vagus nerve stimulator (VNS) placement with three cases cited in literature to date with varying degrees of success. Here the authors report a case of VNS placement for intractable hiccups with partial success, in accordance with SCARE-2018 guidelines. PRESENTATION OF THE CASE: An 85-year-old gentleman with a 9-year history of intractable hiccups secondary to pneumonia came to our hospital. The hiccups were symptomatic causing anorexia, insomnia, irritability, depression, exhaustion, muscle wasting and weight loss. The patient underwent countless medical evaluations. All examinations and investigations yielded normal results. The patient underwent aggressive pharmacotherapy, home remedies and unconventional therapies for intractable hiccups but to no avail. He also underwent left phrenic nerve blocking and resection without therapeutic success. The patient presented to our hospital and decision for VNS insertion was taken for compassionate reasons considering patient morbidity. The patient demonstrated significant improvement in his symptoms following VNS insertion. DISCUSSION: A temporary hiccup is an occasional happening experienced by everyone. However, intractable hiccups are associated with significant morbidity and often mortality. Several medical, pharmacological, surgical and novel treatment options are available for intractable hiccups. CONCLUSION: VNS insertion is a novel surgical option for the treatment of intractable hiccups.

Rare but life-threatening aspiration pneumonia related to initiation of clobazam therapy.

Clobazam (CLB) was approved in October 2011 by the United States FDA as an adjunctive therapy for the treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients older than the age of 2. Due to its unique chemical design and selective binding to the alpha-2 GABA-receptor, CLB has a decreased tendency for sedation compared to other benzodiazepines. A recent literature review shows that sedation, hypersalivation (drooling), and behavior changes are the most common side effects of CLB. It has also been shown that a patient's level of consciousness is indirectly related to the risk of aspiration. Hypersalivation is too is a significant predisposing factor for aspiration. In this report, we present three adult patients with epilepsy who had aspiration pneumonia during treatment with CLB. We would like to raise awareness of increased drooling and somnolence in patients with predisposing factors for aspiration such as treatment with CLB and emphasize vigilance in this regard.

A Tale of Fits and Faint: A Case of Hypervagotonic Nerve Stimulation.

Vagal nerve stimulators are devices used to treat medically refractory epilepsy. Here, we present a rare, unique, and life-threatening side effect of vagal nerve stimulator placement. (Level of Difficulty: Advanced.).

Case of Vagal Nerve Stimulator-Induced Stridor After Anterior Cervical Diskectomy and Fusion-Induced Vocal Cord Paralysis.

BACKGROUND: Vagal nerve stimulation is a generally safe adjunctive treatment for medically refractory epilepsy. Nevertheless, reports of vocal cord dysfunction during stimulation can be found in the literature. When vagal nerve stimulation-induced vocal cord dysfunction is compounded with contralateral dysfunction, such as that which can occur after anterior cervical diskectomy and fusion, serious pulmonary complications can occur. CASE DESCRIPTION: A 56-year-old female presented to the emergency department 3 weeks postoperatively from a cervical 7-thoracic 2 anterior cervical diskectomy and fusion through a right-sided approach with new-onset, intermittent stridor. Otorhinolaryngology conducted a fiberoptic laryngoscopy and determined that the patient had a right vocal cord paralysis and intermittent left vocal cord paresis that coincided with activation of the patient's vagal nerve stimulator. The stimulator was shut off, and the patient's stridor disappeared. CONCLUSIONS: Vagal nerve stimulation-induced vocal cord paralysis is a rare but known complication. Given this potential for vocal cord dysfunction, neurosurgeons should plan further anterior cervical diskectomy and fusions accordingly to ensure that patients do not develop dysfunction of bilateral vocal cords. Should this develop, however, cessation of vagal nerve stimulation can improve or treat the pulmonologic complication that develops.