Effect of Electrode Configuration and Impulse Strength on Airway Patency in Neurostimulation for Obstructive Sleep Apnea.

OBJECTIVES/HYPOTHESIS: Hypoglossal nerve stimulation (HNS) has gained increasing interest for the treatment of patients with obstructive sleep apnea (OSA). Drug-induced sleep endoscopy (DISE) can both exclude improper airway collapse patterns and visualize airway changes under stimulation. Stimulation outcome effects depend on the impulse voltage and electric field resulting from the electrode configuration of the implanted device. The effects of various combinations of voltage and electric field on DISE airway patterns in contrast to awake endoscopy are unknown. STUDY DESIGN: Cohort study. METHODS: During therapy adjustment about 6 months after implantation, patients underwent a DISE and awake endoscopy with 100% and 125% of functional voltage in three typical electrode configurations (+ - +, o - o, - - -). All videos were analyzed by two separate persons for the opening of the airway at velum, tongue base, and epiglottis level. RESULTS: Thirty patients showed typical demographic data. The opening effects were visible in all patients, but there were changes between different electrode configurations. Several demographic or therapeutic aspects such as obesity, OSA severity, or prior soft palate surgery were associated with changes arising from different electrode configurations, but none resulted in a consistently better airway opening. CONCLUSIONS: In patients with poor results during the therapy adjustment, electric configuration changes can improve airway patency-an independent variable from increasing voltage. As these effects can only be seen in awake endoscopy or DISE, both endoscopies with live stimulation may be considered in cases with insufficient improvement in apnea-hypopnea index after initiation of HNS therapy. LEVEL OF EVIDENCE: Prospective case series; level 4. Laryngoscope, 131:2148-2153, 2021.

Takotsubo stress cardiomyopathy following explantation of sEEG electrodes.

Objective: Takotsubo stress cardiomyopathy is characterized by dysfunction of the left ventricle of the heart including apical ballooning and focal wall-motion abnormalities. Although reported in association with seizures and intracerebral hemorrhage, there are no studies reporting its occurrence in patients having stereoelectroencephalography (sEEG). Methods: A 38-year-old lady with no prior history of cardiac disease experienced sudden onset chest pain and acute left ventricular failure 4 hours following explantation of stereoelectroencephalogram electrodes. Results: A small parenchymal hematoma related to the right posterior temporal electrode had been noted postelectrode insertion but was asymptomatic. Focal-onset seizures from nondominant mesial temporal structures were recorded during sEEG. Following the presentation with LVF, new-onset anterolateral T-wave inversion with reciprocal changes in leads II, III, and aVF was noted on electrocardiogram (ECG) and the chest X-ray findings were consistent with pulmonary edema. Echocardiography demonstrated hypokinesis of the cardiac apex and septum consistent with Takotsubo stress cardiomyopathy. Significance: Awareness of the possible complication of Takotsubo stress cardiomyopathy is required in an epilepsy surgery program.

VNS implantation in a NF1 patient: massive nerve hypertrophy discovered intra-operatively preventing successful electrode placement. Case report.

For the vast majority of surgeons, no specific investigation is necessary before vagal nerve stimulation (VNS) implantation. We report our intraoperative unexpected finding of a massively enlarged vagus nerve in a patient with neurofibromatosis type 1 (NF1). The nerve hypertrophy prevented wrapping the coils of the helical electrode. The patient had no signs of vagus nerve dysfunction preoperatively (no hoarseness or dysphonia). This exceptional mishap is undoubtedly related to NF1-associated peripheral nerve sheath tumors. Even though it is not advisable to routinely perform any imaging prior to VNS, in such specific context, preoperative imaging work-up, especially cervical ultrasound, might be judicious to rule out any asymptomatic enlarged left vagus nerve.

Transfer of elements released by aluminum galvanic anodes in a marine sedimentary compartment after long-term monitoring in harbor and laboratory environments.

Cathodic protection by galvanic anodes (GACP) is often used to protect immerged metallic structures in harbor environments, especially GACP employing aluminum-based anodes. To follow a previous study that was performed in a laboratory on Al-anode, two monitoring periods were performed in parallel, one in an in situ environment (in the Port of Calais) for 42 months and the other in a laboratory for 18 months, to evaluate the transfer of metals constituting the Al-anode towards the sedimentary compartment. During each monitoring, two conditions of agitation of water (weak and strong) were compared, and different factors of sediment quality were used to assess the enrichment and potential toxic effects of these released metals. The results showed that the dissolution of Al-anode-induced a greater Zn enrichment of sediment than an Al enrichment. This is in contrast with the abundance of these elements present in the composition of the anode and suggested a potential toxic effect for marine organisms with regards to the discovered Zn level, especially in confined areas.

Endoscopic Pericranial Flap Repair of Occipital-Frontal Electrode Erosion.

INTRODUCTION: Occipital-frontal nerve stimulation is an off-label therapy for treating chronic refractory migraine and orofacial pain. Though effective, patients experience a high rate of complications including lead migration and erosion through the overlying skin. CASE DESCRIPTION: We present a case of frontal electrode erosion that was revised via pericranial flap repair. The patient presented with multiple lead migrations, necessitating multiple revision surgeries with eventual frontal wound dehiscence. The choice was made to wrap the electrode in a pericranial flap to prevent recurrent lead migration. Two weeks postoperatively, the wound was well healed and the patient reported that the midline electrode was functioning properly. DISCUSSION: Pericranial flap revision confers little additional risk when compared with simple wound closure, and the surgeon can proceed without total electrode removal, additional incisions, or lead tunneling. The flap provides a highly vascular additional layer of stability to the electrode, reducing the likelihood of further lead exposure without compromising the efficacy of the device. These results suggest that endoscopic pericranial flap revision is a viable technique for the repair of occipital nerve stimulation lead erosions.

[Shovel-shaped electrode transurethral plasmakinetic enucleation versus plasmakinetic resection of the prostate in the treatment of benign prostatic hyperplasia].

OBJECTIVE: To compare the safety and effectiveness of shovel-shaped electrode transurethral plasmakinetic enucleation of the prostate (PKEP) with those of plasmakinetic resection of the prostate (PKRP) in the treatment of benign prostatic hyperplasia (BPH). METHODS: We retrospectively analyzed the clinical data about 78 BPH patients received in Shanghai Ninth People's Hospital from June 2016 to January 2017, 39 treated by shovel-shaped electrode PKEP and the other 39 by PKRP. We observed the patients for 6 months postoperatively and compared the effects and safety of the two surgical strategies. RESULTS: No statistically significant difference was observed between the PKEP and PKRP groups in the operation time (ï¼»69.3 ± 8.8ï¼½ vs ï¼»72.2 ± 7.9ï¼½ min, P = 0.126), but the former, as compared with the latter, showed a markedly less postoperative loss of hemoglobin (ï¼»3.9 ± 2.8ï¼½ vs ï¼»13.9 ± 5.2ï¼½ g/L, P <0.001) and shorter bladder irrigation time (ï¼»12.5 ± 1.2ï¼½ vs ï¼»43.4 ± 2.8ï¼½ h, P <0.001), catheterization time (ï¼»64.0 ± 4.5ï¼½ vs ï¼»84.8 ± 3.0ï¼½ h, P <0.001) and hospital stay (ï¼»3.1 ± 0.3ï¼½ vs ï¼»5.5 ± 0.4ï¼½ d, P <0.001). There were no statistically significant differences between the PKEP and PKRP groups in the postoperative maximum urinary flow rate (Qmax) (ï¼»21.62 ± 1.07ï¼½ vs ï¼»21.03 ± 0.96ï¼½ ml/s, P = 0.12), International Prostate Symptoms Score (IPSS) (5.85 ± 0.90 vs 6.03 ± 0.81, P = 0.279), quality of life score (QoL) (2.0 ± 0.73 vs 2.28 ± 0.72, P = 0.09), postvoid residual urine volume (PVR) (ï¼»19.59 ± 6.01ï¼½ vs ï¼»20.21 ± 5.16ï¼½ ml, P = 0.629), or the incidence rates of urinary incontinence (2.56% ï¼»1/39ï¼½ vs 7.69% ï¼»3/39ï¼½, P >0.05) and other postoperative complications. CONCLUSIONS: Both PKEP and PKRP are effective methods for the treatment of BPH, but PKEP is worthier of clinical recommendation for a better safety profile, more thorough removal of the prostate tissue, less blood loss, shorter hospital stay, and better improved quality of life of the patient.

Intra-operative cortical motor mapping using subdural grid electrodes in children undergoing epilepsy surgery evaluation and comparison with the conventional extra-operative motor mapping.

OBJECTIVES: The objective of this study was to review our experience with intra-operative "train of five" stimulation using subdural grid for motor mapping in children undergoing epilepsy surgery evaluation. METHODS: Twenty consecutive children below 18-years of age with drug-refractory epilepsy who underwent invasive-EEG monitoring using subdural-grid placement and intra-operative motor mapping using direct cortical stimulation by sub-dural grid electrodes (IODCS-SDG) at our institution between January-2016 and June-2017 were reviewed. Stimulation was delivered through the subdural-grid electrodes using a train-of-five pulses and muscle responses were recorded by motor-evoked-potentials (MEPs). Intra-operative direct cortical stimulation delivered through a ball-tipped probe (IODCS-probe) and extra-operative motor-mapping (EODCS-SDG) were also performed. RESULTS: IODCS-SDG was completed in 20 patients and subsequent EODCS-SDG was done in 17/20 patients. MEP responses were more commonly obtained in the deltoid (19/20), extensor-digitorum-communis (20/20) and first-dorsal-interosseus (19/20). The median thresholds varied between 40 V and 60 V for the six muscle groups. The respective IODCS-probe thresholds tended to be similar. No stimulation-provoked seizures or anaesthesia-related complications were noted during IODCS-SDG. EODCS-SDG could not be completed in 4/17 children and mapping data obtained was frequently inadequate. Nine patients demonstrated 100% concordance between IODCS-SDG and EODCS-SDG for the common mapped body regions. Stimulation-provoked seizures during EODCS-SDG were seen in 6/17 (35.3%) and after-discharges in 7/17 (41.2%) children. CONCLUSIONS: IODCS-SDG could be performed safely in children with drug refractory epilepsy undergoing invasive EEG monitoring. SIGNIFICANCE: IODCS-SDG may be a useful adjunct to EODCS-SDG in motor mapping for children.

Hippocampal deep brain stimulation: persistent seizure control after bilateral extra-cranial electrode fracture.

Hippocampal deep brain stimulation (DBS) can provide an effective alternative for intractable temporal lobe epilepsy. In this case report, we describe a peculiar outcome after a post-traumatic wire-disconnection of a bilateral hippocampal DBS device. The patient presented a postoperative long-term significant reduction in seizure frequency even with an absent electric stimulation. This case gives the possibility to consider alternatives in epilepsy surgery, based on stimulation interference (lesional or electrical disturbing) in the epileptogenic zone.

DBS Electrodes With Single Disconnected Contacts: Long-Term Observation and Implications for the Management.

OBJECTIVES: To evaluate the long-term course of quadripolar DBS electrodes with disconnected single contacts that cannot be used for DBS. MATERIALS AND METHODS: Quadripolar electrodes with open circuits of single contacts or monopolar impedances >6500 Ω were identified from a cohort of 2082 electrodes from 1044 patients with variable movement disorders. The long-term course was analyzed from follow-up data. RESULTS: Disconnected contacts were found in 58 electrodes (2.8%) from 49 patients (4.7%). The dysfunction was restricted to one contact in 51 electrodes (87.9%), two contacts in 5 electrodes (8.6%), three contacts in 2 electrodes (3.4%). Onset was related to surgery (implantation, impulse generator replacement, or other surgical revision) in 34 electrodes (58.6%), trauma in 2 electrodes, undetermined in 11 electrodes, and occurred spontaneously after previous normal measurements in 11 electrodes (19.0%). Repeated measurements at follow-ups of ≥3 months were available in 39 electrodes. In 16 electrodes (41.0%) abnormal impedances persisted constantly during observations up to 11½ years (47 ± 35 months, median 41 months). In 21 electrodes (53.8%) abnormal impedances remained restricted to the initial contact(s) but varied considerably between measurements during up to six years (39 ± 18 months, median 38 months). Only two electrodes (5.1%) with initially one disconnected contact developed a disconnection of a second contact. CONCLUSIONS: Disconnections of single contacts occur with increasing cumulative incidence during long-term DBS. Surgery is the main causative risk factor. In the majority of electrodes, the dysfunction remains restricted to the initial contact(s).

Manipulating an internal pulse generator until twiddler's syndrome in a patient treated with deep brain stimulation for obsessive-compulsive disorder.

BACKGROUND: Twiddler's syndrome consists of rotation or manipulation of an implantable pulse generator (IPG) in its subcutaneous pocket by a patient, thus causing hardware malfunction. METHODS: This syndrome is being reported more frequently in patients treated with deep brain stimulation (DBS). RESULTS: We report the case of a woman who had received bed nucleus of stria terminalis (BNST) electrodes for obsessive-compulsive disorder (OCD) and developed twiddler's syndrome a few months after surgery, causing hardware malfunction due to obsessive manipulation of the IPG. CONCLUSION: The patient did not have compulsions related to touching objects at admission, thus making it difficult to foresee and prevent TS.

Primary cutaneous aspergillosis and idiopathic bone marrow aplasia.

We describe the case of a 9-year-old boy with idiopathic bone marrow aplasia and severe neutropenia, who developed skin ulcers under cardiac monitoring electrodes. The diagnosis of primary cutaneous aspergillosis was made after the second biopsy and culture. Imaging investigation did not reveal internal fungal infection. The child was treated, but did not improve and died 3 months after admission. The report highlights and discusses the preventable risk of aspergillus skin infection in immunocompromised patients.

Prevalence of Complications in Intraoperative Magnetic Resonance Imaging Combined with Neurophysiologic Monitoring.

BACKGROUND AND OBJECTIVE: High-field intraoperative magnetic resonance imaging (ioMRI) is becoming increasingly available in neurosurgery centers, where it has to be combined with intraoperative neurophysiologic monitoring (IONM). IONM needle electrodes remain on the patient during ioMRI and may cause image distortions and burns. We tested magnetic resonance (MR) -heating experimentally and investigated the prevalence of complications. METHODS: We studied electrodes that are certified for IONM, but not "MR conditional." They consist of copper cables (length, 1.5 m) and needles made of either stainless steel (ferromagnetic) or paramagnetic platinum/iridium alloy. We simulated an ioMRI session with gel and measured the temperature increase with optical fibers. We measured the force that an electrode experiences in the magnetic field. Between 2013 and 2016, we prospectively documented subcutaneous needle electrodes that remained in the patient during intraoperative 3 Tesla ioMRI scans. RESULTS: The in vitro testing of the electrodes produced a maximum heating (ΔT = 3.9°C) and force of 0.026 N. We placed 1237 subcutaneous needles in 57 surgical procedures with combined IONM and ioMRI, where needles remained in place during ioMRI. One patient suffered a skin burn on the shoulder. All other electrodes had no side effects. CONCLUSIONS: We have corroborated the history of safe use for electrodes with 1.5 m cable in a 3T MRI scanner and demonstrated their use. Nevertheless, heating cannot be excluded, as it depends on location and cable placement. When leaving electrodes in place during ioMRI, risks and benefits have to be carefully evaluated for each patient.

Primary cutaneous aspergillosis and idiopathic bone marrow aplasia

Abstract: We describe the case of a 9-year-old boy with idiopathic bone marrow aplasia and severe neutropenia, who developed skin ulcers under cardiac monitoring electrodes. The diagnosis of primary cutaneous aspergillosis was made after the second biopsy and culture. Imaging investigation did not reveal internal fungal infection. The child was treated, but did not improve and died 3 months after admission. The report highlights and discusses the preventable risk of aspergillus skin infection in immunocompromised patients.

Deep brain stimulation and development of a high-grade glioma: incidental or causal association?

We report the case of a patient in whom 8.8 years following the implantation of a bilateral deep brain stimulation (DBS) into the Vim, a high-grade glioma was diagnosed in close proximity to the two electrode leads. A possible relationship between the permanent DBS and the development of the brain tumour is discussed.

Separating the Laparoscopic Camera Cord From the Monopolar "Bovie" Cord Reduces Unintended Thermal Injury From Antenna Coupling: A Randomized Controlled Trial.

OBJECTIVE(S): The monopolar "Bovie" is used in virtually every laparoscopic operation. The active electrode and its cord emit radiofrequency energy that couples (or transfers) to nearby conductive material without direct contact. This phenomenon is increased when the active electrode cord is oriented parallel to another wire/cord. The parallel orientation of the "Bovie" and laparoscopic camera cords cause transfer of energy to the camera cord resulting in cutaneous burns at the camera trocar incision. We hypothesized that separating the active electrode/camera cords would reduce thermal injury occurring at the camera trocar incision in comparison to parallel oriented active electrode/camera cords. METHODS: In this prospective, blinded, randomized controlled trial, patients undergoing standardized laparoscopic cholecystectomy were randomized to separated active electrode/camera cords or parallel oriented active electrode/camera cords. The primary outcome variable was thermal injury determined by histology from skin biopsied at the camera trocar incision. RESULTS: Eighty-four patients participated. Baseline demographics were similar in the groups for age, sex, preoperative diagnosis, operative time, and blood loss. Thermal injury at the camera trocar incision was lower in the separated versus parallel group (31% vs 57%; P = 0.027). CONCLUSIONS: Separation of the laparoscopic camera cord from the active electrode cord decreases thermal injury from antenna coupling at the camera trocar incision in comparison to the parallel orientation of these cords. Therefore, parallel orientation of these cords (an arrangement promoted by integrated operating rooms) should be abandoned. The findings of this study should influence the operating room setup for all laparoscopic cases.

Thalamotomy-Like Effects From Partial Removal of a Ventral Intermediate Nucleus Deep Brain Stimulator Lead in a Patient With Essential Tremor: Case Report.

BACKGROUND AND IMPORTANCE: The ventral intermediate nucleus of the thalamus is a primary target of deep brain stimulation (DBS) in patients with essential tremor. Despite reliable control of contralateral tremor, there is sometimes a need for lead revision in cases of infection, hardware malfunction, or failure to relieve symptoms. Here, we present the case of a patient undergoing revision after ventral intermediate nucleus (Vim) DBS failed to control his tremor. During the electrode removal, the distal portion of the lead was found to be tightly adherent to tissue within the deep brain. Partial removal of the electrode in turn caused weakness, paresthesias, and tremor control similar to the effects produced by thalamotomy or thalamic injury. CLINICAL PRESENTATION: A 48-year-old man with essential tremor had bilateral Vim DBS leads implanted 10 years earlier but had poor control of his tremor and ultimately opted for surgical revision with lead placement in the zona incerta. During attempted removal of his right lead, the patient became somnolent with contralateral weakness and paresthesias. The procedure was aborted, and postoperative neuroimaging was immediately obtained, showing no signs of stroke or hemorrhage. The patient had almost complete control of his left arm tremor postoperatively, and his weakness soon resolved. CONCLUSION: To the best of our knowledge, this is the first reported case of cerebral injury after DBS revision and offers insights into the mechanism of high-frequency electric stimulation compared with lesions. That is, although high-frequency stimulation failed to control this patient's tremor, thalamotomy-like injury was completely effective.

[Bispectral Index Electrodes May Induce Skin Lesions].

Bispectral index (BIS) monitoring has been used since the 1990 s, and many studies on BIS monitoring have demonstrated its usefulness and safety. Currently, BIS monitoring has become indispensable for observation of patients under general anesthesia. However, we observed the development of postoperative skin lesions in 13 patients (11 female and 2 male; age range, 14-76 years) resulting from contact with the BIS electrodes between May 2012 and April 2013. None of the patients had a history of allergies or skin diseases prior to surgery. During the surgery, nine patients were placed in the supine position and four in the prone position. The duration of anesthesia ranged from 2 hr 7 min to 13 hr. The overall incidence of skin lesions was approximately 0.27% (13/4,900), and that in patients in the prone position was 3.1% (4/129). The skin lesions resolved within 1 week without scaring following the application of a steroid-containing ointment. Although the occurrence of such skin complications is rare, some patients may experience postoperative anxiety because skin lesions caused by BIS electrodes are noticeable. Therefore, both the usefulness of BIS monitoring and the potential skin complications should be explained to patients preoperatively prior to obtaining patient consent.

Febre de origem indeterminada em portador de marcapasso definitivo / Fever of unknown origin in permanent pacemaker carrier

O implante de marcapasso tem sido cada vez mais utilizado, em decorrência de sua segurança e dos baixos índices de complicação. No entanto, a infecção de dispositivos é um quadro grave, que apresenta elevada morbimortalidade e alto custo de tratamento. Algumas vezes essa infecção evolui com endocardite bacteriana, complicação cuja incidência vem aumentando nos últimos anos. É de difícil diagnóstico e tratamento, seja pela inespecificidade dos sintomas clínicos seja pela variação dos achados de imagem no ecocardiograma. Descrevemosum caso de febre de origem indeterminada em portador de marcapasso, que investigação posterior demonstrou ser decorrente de infecção dos cabos-eletrodos e de endocardite secundária. O paciente foi tratado comantibioticoterapia prolongada e retirada do sistema por cirurgia aberta.

Pacemaker implantation has increased due to their safety and low complications rate. However, the infection of the devices is a serious event with high morbidity and mortality rates and high treatment cost. Infections may evolve to bacterial endocarditis, whose incidence has increased in the last years. It is difficult to diagnose and treat due to the unspecificity of clinical symptoms and variation in imaging findings at theechocardiogram. We report a case of fever of unknown origin in a pacemaker carrier, which later proved to havebeen caused by electrode-cable infection and secondary endocarditis. The patient was treated with prolonged antibiotic therapy and retrieval of the device by open surgery.

Case report: rare case of mechanical bowel obstruction due to strangulation by gastric stimulator electrodes.

BACKGROUND: Implantation of a gastric stimulator is a feasible surgical therapy for patients with therapy refractory gastroparesis. In addition it seems to be a promising alternative for treating morbid obesity. We present for the first time the surgical emergency of small bowel obstruction due to strangulation by gastric stimulator electrodes. CASE PRESENTATION: A 59-year-old Caucasian female had undergone implantation of a gastric stimulator to cope with the symptoms of a partial gastroparesis. Eight years after the operation, the patient began to present repeatedly to different hospitals because of abdominal pain and nausea. Symptoms and imaging indicated ileus, which could always be treated conservatively. The underlying pathology could not ultimately be determined and the symptoms were eventually considered gastroparesis-related. After two years the patient was finally referred in circulatory shock due to peritonitis with underlying small bowel obstruction. Emergency laparotomy revealed small bowel strangulation by the gastric stimulator electrodes. CONCLUSION: Repeated presentation of a patient with an unfamiliar treatment modality must raise suspicion of unusual complications. Specialist surgeons treating with innovative methods should provide proper information that is accessible to everyone who might have to treat possible complications.