Implantable Pulse Generator Replacement Research Articles

Risk factors for postoperative urinary retention after deep brain stimulation surgery: the role of the subthalamic nucleus.

Deep brain stimulation (DBS) is a common procedure in neurosurgery used for the treatment of Parkinson's disease (PD) and essential tremor (ET) among other disorders. Lower urinary tract dysfunction is a common complication in PD, and this study aimed to evaluate the risk factors of postoperative urinary retention (POUR) after DBS surgery in patients with PD compared with patients with ET. Understanding the risk factors associated with this complication may help in the development of strategies to minimize its occurrence and improve patient outcomes. The study was a retrospective analysis of patients who underwent DBS surgery for PD and ET at the University of Florida between 2010 and 2021. The surgical technique used has been described in previous articles and included a two-stage procedure, with stage 1 involving burr hole placement, microelectrode recording, and electrode implantation and stage 2 involving the placement of an implantable pulse generator (IPG). Data were collected on patient characteristics and surgical details and analyzed using univariate and mixed-linear models. Post hoc propensity score matching was used to confirm the association between subthalamic nucleus (STN)-DBS and POUR. The study included 350 patients (153 with PD and 197 with ET) who underwent 1086 DBS surgeries (lead implantations, IPG placement, and IPG replacements). The POUR rates were 16.6% (79/477), 5.2% (19/363), and 0.4% (1/246) for stage 1, stage 2, and IPG replacement procedures, respectively. Optimal mixed-effects logistic modeling revealed history of urinary retention (OR 9.3, p = 0.004), male sex (OR 2.7, p = 0.011), having an electrode placed or connected for the first time (OR 2.2, p = 0.014), anesthesia time (OR 1.5 for each 30-minute increase, p < 0.0001), preoperative opioid use (OR 1.4 for each additional 10 morphine milligram equivalents, p = 0.032), and Charlson Comorbidity Index (OR 1.4 per comorbidity, p = 0.017) to be significant risk factors for POUR. Having an electrode in the STN was found to be protective of POUR (propensity score-matched analysis: OR 0.2, p = 0.010). Most risk factors found to increase the risk of POUR in DBS are not modifiable but are still important to consider in preoperative planning. Opioid use reduction and shorter anesthesia time may be modifiable risk factors to weigh against their alternative. Targeting the STN during DBS may result in decreased rates of POUR. This highlights the potential for STN-targeted DBS in reducing POUR risk in PD and ET patients.

149 Quantitative Performance Assessment of a Wirelessly Powered Vagus Nerve Stimulator in a Porcine Model

INTRODUCTION: Electrophysiological stimulation has been widely used in the management of various disorders, including neurological and cardiac disorders. The dependence on an implantable pulse generator (IPG) increases the risk of surgical complications, patient discomfort, and need for IPG replacement surgery in stimulation methods. Wireless and batteryless stimulators offer important capabilities such reduced need for reoperation, and shorter surgical time compared to their wired counterparts. However, stable quantitative functionality assessment of wireless systems is an essential requirement for their practical usage. METHODS: In vivo studies were performed in three anesthetized male pigs. Conventional wired stimulation using bipolar electrodes and a wireless stimulator using the circular wireless receiver (ø 13 mm, 483 mg) with cuff electrodes were implanted around the right Vagus nerve of all animals. Stimulation was performed at varying frequencies (1–20 Hz), and pulse widths (0.1–1 ms) using both systems. Heart rate, left ventricle pressure, and EKG were monitored during VNS. A paired t-test was used to compare physiological responses to different VNS systems. RESULTS: A total of 84 stimulations by the wireless device and 36 stimulations by the conventional system were performed. 72% of wireless device stimulations and 75% of the conventional VNS stimulations led to significant heart rate reduction (P &lt; 0.05, paired t-test). There was no significant difference between conventional and wireless systems when comparing physiological markers in response to different pulse widths and stimulation frequencies. CONCLUSIONS: This study quantitatively compared functionality of a novel wireless and batteryless VNS system to a conventional VNS, and can serve as a basis for future wirelessly powered implants in the field of neurosurgery to assess functionality and perform close loop stimulation using physiological markers.

Choice of Implantable Pulse Generators for Deep Brain Stimulation: An Overview of Clinical Practice

Introduction: The success of deep brain stimulation (DBS) treatment depends on several factors, including proper patient selection, accurate electrode placement, and adequate stimulation settings. Another factor that may impact long-term satisfaction and therapy outcomes is the type of implantable pulse generator (IPG) used: rechargeable or non-rechargeable. However, there are currently no guidelines on the choice of IPG type. The present study investigates the current practices, opinions, and factors DBS clinicians consider when choosing an IPG for their patients. Methods: Between December 2021 and June 2022, we sent a structured questionnaire with 42 questions to DBS experts of two international, functional neurosurgery societies. The questionnaire included a rating scale where participants could rate the factors influencing their choice of IPG type and their satisfaction with certain IPG aspects. Additionally, we presented four clinical case scenarios to assess preference of choice of IPG-type in each case. Results: Eighty-seven participants from 30 different countries completed the questionnaire. The three most relevant factors for IPG choice were “existing social support,” “cognitive status,” and “patient age.” Most participants believed that patients valued avoiding repetitive replacement surgeries more than the burden of regularly recharging the IPG. Participants reported that they implanted the same amount of rechargeable as non-rechargeable IPGs for primary DBS insertions and 20% converted non-rechargeable to rechargeable IPGs during IPG replacements. Most participants estimated that rechargeable was the more cost-effective option. Conclusion: This present study shows that the decision-making of the choice of IPG is very individualized. We identified the key factors influencing the physician’s choice of IPG. Compared to patient-centric studies, clinicians may value different aspects. Therefore, clinicians should rely not only on their opinion but also counsel patients on different types of IPGs and consider the patient’s preferences. Uniform global guidelines on IPG choice may not represent regional or national differences in the healthcare systems.

Predictive nomogram for deep brain stimulation-related infections.

Infection is one of the important and frequent complications following implantable pulse generator and deep brain stimulation (DBS) electrode insertion. The goal of this study was to retrospectively evaluate and identify potential risk factors for DBS infections. From January 2015 to January 2021 in Qingdao municipal hospital (training cohort) and The First Affiliated Hospital of the University of Science and Technology of China (validation cohort), the authors enrolled patients with Parkinson disease who had undergone primary DBS placement or implantable pulse generator replacement. The cases were divided into infection or no-infection groups according to the 6-month follow-up. The authors used the logistic regression models to determine the association between the variables and DBS infection. Depending on the results of logistic regression, the authors established a nomogram. The calibration curves, receiver operating characteristic curve analysis, and decision curves were used to evaluate the reliability of the nomogram. There were 191 cases enrolled in the no-infection group and 20 cases in the infection group in the training cohort. The univariate logistic regression showed that BMI, blood glucose, and albumin were all significant predictors of infection after DBS surgery (OR 0.832 [p = 0.009], OR 1.735 [p < 0.001], and OR 0.823 [p = 0.001], respectively). In the crude, adjust I, and adjust II models, the three variables stated above were all considered to be significant predictors of infection after DBS surgery. The calibration curves in both training and validation cohorts showed that the predicted outcome fitted well to the observed outcome (p > 0.05). The decision curves showed that the nomogram had more benefits than the "All or None" scheme. The areas under the curve were 0.93 and 0.83 in the training and validation cohorts, respectively. The nomogram included BMI, blood glucose, and albumin, which were significant predictors of infection in patients with DBS surgery. The nomogram was reliable for clinical application.

Surgical and Hardware-Related Adverse Events of Deep Brain Stimulation: A Ten-Year Single-Center Experience

IntroductionAlthough deep brain stimulation (DBS) is effective for treating a number of neurological and psychiatric indications, surgical and hardware-related adverse events (AEs) can occur that affect quality of life. This study aimed to give an overview of the nature and frequency of those AEs in our center and to describe the way they were managed. Furthermore, an attempt was made at identifying possible risk factors for AEs to inform possible future preventive measures. Materials and MethodsPatients undergoing DBS-related procedures between January 2011 and July 2020 were retrospectively analyzed to inventory AEs. The mean follow-up time was 43 ± 31 months. Univariate logistic regression analysis was used to assess the predictive value of selected demographic and clinical variables. ResultsFrom January 2011 to July 2020, 508 DBS-related procedures were performed including 201 implantations of brain electrodes in 200 patients and 307 implantable pulse generator (IPG) replacements in 142 patients. Surgical or hardware-related AEs following initial implantation affected 40 of 200 patients (20%) and resolved without permanent sequelae in all instances. The most frequent AEs were surgical site infections (SSIs) (9.95%, 20/201) and wire tethering (2.49%, 5/201), followed by hardware failure (1.99%, 4/201), skin erosion (1.0%, 2/201), pain (0.5%, 1/201), lead migration (0.52%, 2/386 electrode sites), and hematoma (0.52%, 2/386 electrode sites). The overall rate of AEs for IPG replacement was 5.6% (17/305). No surgical, ie, staged or nonstaged, electrode fixation, or patient-related risk factors were identified for SSI or wire tethering. ConclusionsMajor AEs including intracranial surgery–related AEs or AEs requiring surgical removal or revision of hardware are rare. In particular, aggressive treatment is required in SSIs involving multiple sites or when Staphylococcus aureus is identified. For future benchmarking, the development of a uniform reporting system for surgical and hardware-related AEs in DBS surgery would be useful.

Breast Cancer Incidentally diagnosed during Implantable Pulse Generator Replacement in a Patient treated with Deep Brain Stimulation : Importance of Breast Cancer Screening in Patients with Implantable Pulse Generator

Breast Cancer Incidentally diagnosed during Implantable Pulse Generator Replacement in a Patient treated with Deep Brain Stimulation : Importance of Breast Cancer Screening in Patients with Implantable Pulse Generator

North American survey on impact of the COVID-19 pandemic shutdown on DBS care

BackgroundThe initial COVID-19 pandemic shutdown led to the canceling of elective surgeries throughout most of the USA and Canada. ObjectiveThis survey was carried out on behalf of the Parkinson Study Group (PSG) to understand the impact of the shutdown on deep brain stimulation (DBS) practices in North America. MethodsA survey was distributed through RedCap® to the members of the PSG Functional Neurosurgical Working Group. Only one member from each site was asked to respond to the survey. Responses were collected from May 15 to June 6, 2020. ResultsTwenty-three sites participated; 19 (83%) sites were from the USA and 4 (17%) from Canada. Twenty-one sites were academic medical centers. COVID-19 associated DBS restrictions were in place from 4 to 16 weeks. One-third of sites halted preoperative evaluations, while two-thirds of the sites offered limited preoperative evaluations. Institutional policy was the main contributor for the reported practice changes, with 87% of the sites additionally reporting patient-driven surgical delays secondary to pandemic concerns. Pre-post DBS associated management changes affected preoperative assessments 96%; electrode placement 87%; new implantable pulse generator (IPG) placement 83%; IPG replacement 65%; immediate postoperative DBS programming 74%; and routine DBS programming 91%. ConclusionThe COVID-19 pandemic related shutdown resulted in DBS practice changes in almost all North American sites who responded to this large survey. Information learned could inform development of future contingency plans to reduce patient delays in care under similar circumstances.

Diplopia associated with loop routing in deep brain stimulation: illustrative case.

BACKGROUNDDeep brain stimulation (DBS) is a powerful surgical option for drug-resistant movement disorders; however, electromagnetic interference (EMI) from external sources poses a potential risk for implanted electronics.OBSERVATIONSA 61-year-old woman with Parkinson’s disease originally had two implantable pulse generators (IPGs) for bilateral subthalamic DBS, which were then replaced with one dual-channel IPG routed in a loop. After the replacement surgery, with the same DBS programming as before the IPG replacement (bipolar setting for right, unipolar setting for left), the patient began to complain of transient paroxysmal diplopia. After multiple attempts to adjust the stimulation parameters, the diplopia was resolved by changing the left unipolar setting to a bipolar setting. At the authors’ institution, before the present case, four other patients had undergone IPG replacement with loop routing. None of these previous patients complained of diplopia; however, two of the four presented with diplopia in an experimental unipolar setting.LESSONSClinicians should be aware that loop-routed circuits may generate distortion of the stimulus field in DBS, even in the absence of external EMI sources.

Parkinsonism management issues in a patient with exhausted subthalamic deep brain stimulation battery, stricken by severe acute respiratory syndrome coronavirus 2.

Background: Nowadays, many neurological conditions, including Parkinson’s disease (PD), are treated with deep brain stimulation (DBS). Life-threatening consequences can occur from DBS hardware failure or sudden implantable pulse generator (IPG) battery depletion. This issue may potentially worsen in concomitance with medical or infectious conditions, requiring stronger emergency management. Methods: We present here a 58 year-old PD patient with DBS, whose IPG replacement surgery was complicated by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and we report management of this patient along with recommendations for patients with similar situation. Results: As the newly-emerged coronavirus disease 2019 (COVID-19) is now announced to be pandemic, new protocols and specific measures for each individual group of patients with chronic diseases seem obligatory. Regarding our recent experience with a patient suffering from PD, on DBS treatment, who needed hospitalization, we felt useful to share our experience as a recommended protocol for similar patients in the time of current pandemic. Conclusion: Close monitoring of laboratory and clinical signs should be warranted in patients with PD awaiting IPG replacement in order to be prepared in these novel conditions that may precipitate an akinetic crisis/dystonic storm and to prevent life-threatening complications during the current pandemic.

Pulse Width and Implantable Pulse Generator Longevity in Pallidal Deep Brain Stimulation for Dystonia: A Population-Based Comparative Effectiveness Study

Introduction: A wide range of pulse widths (PWs) has been used in globus pallidus internus (GPi) deep brain stimulation (DBS) for dystonia. However, no specific PW has demonstrated clinical superiority, and the paradigm may differ among DBS centers. Objective: To investigate how different paradigms of PWs in GPi DBS for dystonia affect implantable pulse generator (IPG) longevities and energy consumption. Methods: Thirty-nine patients with dystonia treated with bilateral GPi DBS at 2 Swedish DBS centers from 2005 to 2015 were included. Different PW paradigms were used at the 2 centers, 60–90 µs (short PWs) and 450 µs (long PW), respectively. The frequency of IPG replacements, pulse effective voltage (PEV), IPG model, pre-/postoperative imaging, and clinical outcome based on the clinical global impression (CGI) scale were collected from the medical charts and compared between the 2 groups. Results: The average IPG longevity was extended for the short PWs (1,129 ± 50 days) compared to the long PW (925 ± 32 days; χ² = 12.31, p = 0.0005, log-rank test). IPG longevity correlated inversely with PEV (Pearson’s r = –0.667, p < 0.0001). IPG longevities did not differ between Kinetra® and Activa® PC in the short (p = 0.319) or long PW group (p = 0.858). Electrode distances to the central sensorimotor region of the GPi did not differ between the short or long PW groups (p = 0.595). Pre- and postoperative CGI did not differ between groups. Conclusions: Short PWs were associated with decreased energy consumption and increased IPG longevity. These effects were not dependent on the IPG model or the anatomic location of the electrodes. PWs did not correlate with symptom severities or clinical outcomes. The results suggest that the use of short PWs might be more energy efficient and could therefore be preferred initially when programming patients with GPi DBS for dystonia.

Clinical Efficacy of Bilateral Deep Brain Stimulation Does Not Change After Implantable Pulse Generator Replacement but the Impedances Do: A Prospective Study

Deep brain stimulation (DBS) is an approved therapy option for movement disorders such as Parkinson's disease (PD), essential Tremor (ET), and dystonia. While current research focuses on rechargeable implantable pulse generators (IPGs), little is known about changes of the motor functions after IPG replacement and the consequences of additionally implanted hardware. To assess changes of the motor functions, the therapy impedances, and the total electric energy delivered (TEED) after elective IPG replacement. We prospectively acquired the data of 47 patients with PD, ET, and dystonia treated with bilateral DBS. Motor functions were rated prior to and after surgery using the revised Unified Parkinson's Disease Rating Scale part III (MDS-UPDRS-III), the Fahn-Tolosa-Marin Tremor-Rating-Scale (FTM-TRS), and the Unified Dystonia Rating Scale (UDRS). Furthermore, the therapy impedances and TEED were assessed at the aforementioned times. While preoperative motor scores were 48.32 ± 17.16 in PD, 39.71 ± 12.28 in ET, and 18.48 ± 16.30 in dystonia patients, postoperative scores were 47.84 ± 24.33, 32.86 ± 15.82, and 15.02 ± 15.17, respectively. Only in dystonia patients, motor scores significantly differed. Perioperative therapy impedance changes were 142.66 ± 105.35 Ω (Kinetra® to Activa® PC), -68.75 ± 43.05 Ω (Activa® PC to Activa® PC), and - 51.38 ± 38.75 Ω (Activa® PC to Activa® RC). Perioperative TEED changes were - 37.15 ± 38.87 μJ, 2.03 ± 35.91 μJ, and 12.39 ± 6.31 μJ in that first, second, and third group, respectively. Both the therapy impedances and TEED significantly differed between groups. Although there were no statistically significant changes in the motor functions of all patients after elective IPG replacement, the therapy impedances were significantly higher and TEED was significantly lower after IPG replacement with concurrent Pocket Adapter implantation.

Implementation of New Technology in Patients with Chronic Deep Brain Stimulation: Switching from Non-Rechargeable Constant Voltage to Rechargeable Constant Current Stimulation

Introduction: Deep brain stimulation (DBS) for movement disorders has been mainly performed with constant voltage (CV) technology. More recently also constant current (CC) systems have been developed which theoretically might have additional advantages. Furthermore, rechargeable (RC) system implantable pulse generators (IPG) are increasingly being used rather than the former solely available non-rechargeable (NRC) IPGs. Objective: To provide a systematic investigation how to proceed and adapt settings when switching from CV NRC to CC RC technology. Methods: We prospectively collected data from 11 consecutive patients (10 men, mean age at DBS implantation 52.6 ± 14.0 years) with chronic DBS for dystonia (n = 7), Parkinson disease (n = 3), and essential tremor (n = 1) who underwent IPG replacement switching from a CV NRC system (Activa® PC; Medtronic®) to a CC RC system (Vercise® RC; Boston Scientific®). Systematic assessments before and after IPG replacement were performed. Results: DBS technology switching at the time of IPG replacement due to battery depletion was at a mean of 108.5 ± 46.2 months of chronic DBS. No perioperative complications occurred. Clinical outcome was stable with overall mild improvements or deteriorations, which could be dealt with in short-term follow-up. Patients were satisfied with the new RC IPG. Conclusions: This study confirms both the safety and feasibility of switching between different DBS technologies (CV to CC, NRC to RC, different manufacturers) in patients with chronic DBS. Furthermore, it shows how the management can be planned using available information from the previous DBS settings. Individual assessment is needed and might partly be related to the DBS target and the underlying disease. MR safety might be a problem with such hybrid systems.

Reduced long-term cost and increased patient satisfaction with rechargeable implantable pulse generators for deep brain stimulation.

Deep brain stimulation (DBS) has revolutionized the treatment of neurological disease, but its therapeutic efficacy is limited by the lifetime of the implantable pulse generator (IPG) batteries. At the end of the battery life, IPG replacement surgery is required. New IPGs with rechargeable batteries (RC-IPGs) have recently been introduced and allow for decreased reoperation rates for IPG replacements. The authors aimed to examine the merits and limitations of these devices. The authors reviewed the medical records of patients who underwent DBS implantation at their institution. RC-IPGs were placed either during initial DBS implantation or during an IPG change. A cost analysis was performed that compared RC-IPGs with standard IPGs, and telephone patient surveys were conducted to assess patient satisfaction. The authors identified 206 consecutive patients from 2011 to 2016 who underwent RC-IPG placement (mean age 61 years; 67 women, 33%). Parkinson's disease was the most common indication for DBS (n = 144, 70%), followed by essential tremor (n = 41, 20%), dystonia (n = 13, 6%), depression (n = 5, 2%), multiple sclerosis tremor (n = 2, 1%), and epilepsy (n = 1, 0.5%). DBS leads were typically placed bilaterally (n = 192, 93%) and targeted the subthalamic nucleus (n = 136, 66%), ventral intermediate nucleus of the thalamus (n = 43, 21%), internal globus pallidus (n = 21, 10%), ventral striatum (n = 5, 2%), or anterior nucleus of the thalamus (n = 1, 0.5%). RC-IPGs were inserted at initial DBS implantation in 123 patients (60%), while 83 patients (40%) were converted to RC-IPGs during an IPG replacement surgery. The authors found that RC-IPG implantation resulted in $60,900 of cost savings over the course of 9 years. Furthermore, patient satisfaction was high with RC-IPG implantation. Overall, 87.3% of patients who responded to the survey were satisfied with their device, and only 6.7% found the rechargeable component difficult to use. In patients who were switched from a standard IPG to RC-IPG, the majority who responded (70.3%) preferred the rechargeable IPG. RC-IPGs can provide DBS patients with long-term therapeutic benefit while minimizing the need for battery replacement surgery. The authors have implanted rechargeable stimulators in 206 patients undergoing DBS surgery, and here they demonstrate the cost-effectiveness and high patient satisfaction associated with this procedure.

Detection of bacterial DNA on neurostimulation systems in patients without overt infection

ObjectiveHardware-related infection remains a major problem in patients with neurostimulation systems. The role of bacterial colonization and the formation of biofilm on the surface of implanted devices remain unclear. Here, we analysed the incidence of bacterial DNA on the surface of implantable pulse generators (IPGs) using 16S rRNA gene sequencing in a consecutive series of patients who underwent routine IPG replacement without clinical signs of infection. Patients and methodsWe included 36 patients who underwent scheduled replacement surgery of 44 IPGs. The removed IPGs were processed and whole genomic DNA was extracted. The detection of bacterial DNA was carried out by Polymerase Chain Reaction (PCR) using universal bacterial primers targeting the 16S rRNA gene. The DNA strands were analysed by single-strand conformation polymorphism (SSCP) analysis. ResultsIndications for chronic neurostimulation were Parkinson disease, tremor, dystonia, neuropathic pain and peripheral artery occlusion disease. Mean age of patients at the time of implantation was 48 ± 17.6 years. The mean interval between implantation and replacement of the IPG was 24.8 months. PCR/SSCP detected bacterial DNA of various species in 5/36 patients (13.9%) and in 5/44 pacemakers (11.4%), respectively. There was no evidence of clinical infection or wound healing impairment during follow-up time of 45.6 ± 19.6 months. ConclusionBacterial DNA can be detected on the surface of IPGs of neurostimulation systems in patients without clinical signs of infection by using PCR techniques. It remains unclear, similar to other permanently implanted devices, which mechanisms and processes promote progression to the point of overt infection.

Neurological Worsening After Implantable Pulse Generator Replacement.

Most of the implantable pulse generators (IPGs) in deep brain stimulation (DBS) used to date are non-rechargeable requiring regular replacements. IPG replacement is a minor surgical procedure, but adverse events including neurological worsening have been reported. In this study, we determine the possibility of neurological worsening after IPG replacement in Parkinson's disease (PD) cases on chronic DBS therapy (CDT) and its electrophysiological basis along with the therapeutic interventions used to alleviate them. This study is a retrospective chart review of PD cases on CDT followed at London Movement Disorders Centre from January 2010 to December 2016. Included cases were those who underwent one or more IPG replacement. A total of 45 PD cases on CDT underwent 62 IPG replacements involving 121 channels. Neurological worsening was observed in 16 (35.5%) cases following 17 (27.4%) IPG replacements, all following dual-channel IPG replacements. Tremor (41.2%), speech (35.3%), and gait (23.5%) worsened most commonly. Deviation from the pre-replacement parameters including voltage and impedance resulting in change in total electrical energy delivered (TEED) was the most common electrophysiological correlate, observed in 82.4% (14/17) IPGs having neurological worsening. This included switched laterality in a dual-channel IPG. Neurological worsening in the remaining 17.6% cases was hardware-related. Neurological worsening followed 27.4% of IPG replacements in PD cases on CDT with approximately 82.4% of these being avoidable by carefully monitoring stimulation parameters to match pre-replacement TEED values.

Reoperation for device infection and erosion following deep brain stimulation implantable pulse generator placement.

Infection and erosion following implantable pulse generator (IPG) placement are associated with morbidity and cost for patients with deep brain stimulation (DBS) systems. Here, the authors provide a detailed characterization of infection and erosion events in a large cohort that underwent DBS surgery for movement disorders. The authors retrospectively reviewed consecutive IPG placements and replacements in patients who had undergone DBS surgery for movement disorders at the University of Alabama at Birmingham between 2013 and 2016. IPG procedures occurring before 2013 in these patients were also captured. Descriptive statistics, survival analyses, and logistic regression were performed using generalized linear mixed effects models to examine risk factors for the primary outcomes of interest: infection within 1 year or erosion within 2 years of IPG placement. In the study period, 384 patients underwent a total of 995 IPG procedures (46.4% were initial placements) and had a median follow-up of 2.9 years. Reoperation for infection occurred after 27 procedures (2.7%) in 21 patients (5.5%). No difference in the infection rate was observed for initial placement versus replacement (p = 0.838). Reoperation for erosion occurred after 16 procedures (1.6%) in 15 patients (3.9%). Median time to reoperation for infection and erosion was 51 days (IQR 24-129 days) and 149 days (IQR 112-285 days), respectively. Four patients with infection (19.0%) developed a second infection requiring a same-side reoperation, two of whom developed a third infection. Intraoperative vancomycin powder was used in 158 cases (15.9%) and did not decrease the infection risk (infected: 3.2% with vancomycin vs 2.6% without, p = 0.922, log-rank test). On logistic regression, a previous infection increased the risk for infection (OR 35.0, 95% CI 7.9-156.2, p < 0.0001) and a lower patient BMI was a risk factor for erosion (BMI ≤ 24 kg/m2: OR 3.1, 95% CI 1.1-8.6, p = 0.03). IPG-related infection and erosion following DBS surgery are uncommon but clinically significant events. Their respective timelines and risk factors suggest different etiologies and thus different potential corrective procedures.

First-in-human implantation of a mid-field powered neurostimulator at the sacral nerve: Results from an acute study.

Commercially approved implantable systems for sacral neuromodulation require the implantation of a multipolar lead subcutaneously connected to an implantable pulse generator (IPG). Eliminating the need for an IPG would eliminate the need for tunneling of the lead, reduce procedure time, infection risk, and the need for IPG replacement. The objective was to demonstrate the feasibility of implanting the AHLeveeS System in the S3 Foramen to stimulate the S3 sacral nerve. A first-in-human, prospective, single center, nonrandomized, acute feasibility clinical investigation at the Maastricht University Medical Center+. Patients with refractory overactive bladder underwent acute implantation of the AHLeveeS neurostimulator before the InterStim procedure. Outcome measurements included motor responses, procedural time and a scoring of the difficulty of the implant and explant procedure. Retrospectively, qualitative responses to the stimulation protocol were assessed by video motion analyses. Only descriptive statistics were used. During the stimulation a motor response to stimulation was seen in four of the five subjects. In all implantations the AHLeveeS was correctly placed. The median time for complete procedure was 24 minutes. The implant and explant procedures were successfully performed and no device or procedure related adverse events occurred. The results from this acute first-in-human study demonstrate the feasibility of implantation and acute stimulation of the sacral nerve with this mid-field powered system. Future clinical studies will focus on safety and efficacy of a chronically implanted device.

Decreasing battery life in subthalamic deep brain stimulation for Parkinson's disease with repeated replacements: Just a matter of energy delivered?

BackgroundPeople with Parkinson's disease (PD) treated with deep brain stimulation (DBS) with non-rechargeable implantable pulse generators (IPGs) require elective IPG replacement operations involving surgical and anesthesiologic risk. Life expectancy and the number of replacements per patient with DBS are increasing. ObjectiveTo determine whether IPG longevity is influenced by stimulation parameters alone or whether there is an independent effect of the number of battery replacements and IPG model. MethodsPD patients treated with bilateral subthalamic DBS were included if there was at least one IPG replacement due to battery end of life. Fifty-five patients had one or two IPG replacements and seven had three or four replacements, (80 Kinetra® and 23 Activa-PC®). We calculated longevity corrected for total electrical energy delivered (TEED) and tested for the effect of IPG model and number of previous battery replacements on this measure. ResultsTEED-corrected IPG longevity for the 1st implanted IPG was 51.3 months for Kinetra® and 35.6 months for Activa-PC®, which dropped by 5.9 months and 2.8 months, respectively with each subsequent IPG replacement (p < 10–6 for IPG model and p < 10–3 for IPG number). ConclusionsActiva-PC® has shorter battery longevity than the older Kinetra®, battery longevity reduces with repeated IPG replacements and these findings are independent of TEED. Battery longevity should be considered both in clinical decisions and in the design of new DBS systems. Clinicians need accessible, reliable and user-friendly tools to provide online estimated battery consumption and end of life. Furthermore, this study supports the consideration of using rechargeable IPGs in PD.

Dysfunctional hypoglossal nerve stimulator after electrical cardioversion: A case series

Upper airway stimulation has demonstrated marked improvements in apnea-hypopnea index, oxygen desaturation index, and quality-of-life measures in patients with moderate to severe obstructive sleep apnea (OSA) who cannot tolerate continuous positive airway pressure. Cardiac arrhythmias are common in patients with OSA and can require electrical cardioversion. We describe the first four reported cases of hypoglossal nerve stimulator (HGNS) dysfunction after electrical cardioversion and illustrate our operative approach to device troubleshooting and repair. Retrospective case series. A retrospective review of 201 HGNS implantations performed at two academic institutions revealed four cases of HGNS device dysfunction after electrical cardioversion requiring surgical revision. Preoperative and postoperative device performance metrics and electrical cardioversion specifications were retrospectively assessed and compiled for this case series. The senior authors (R.J.S., M.S.B.) detail operative planning and approach for HGNS implantable pulse generator (IPG) replacement. At least two patients with HGNS device dysfunction had received cardioversion via anterolateral electrode pad placement. Three patients had received multiple shocks. All four patients experienced a change in device functionality or complete cessation of functionality after electrocardioversion. Operatively, each patient required replacement of the IPG, with subsequent intraoperative interrogation revealing proper device functionality. Counseling for patients with HGNS undergoing external electrical cardioversion should include possible device damage and need for operative replacement. Anteroposterior electrode pad placement should be considered for patients with HGNS who require electrocardioversion. Operative replacement of an HGNS system damaged by electrocardioversion begins with IPG replacement and intraoperative device interrogation. 4 Laryngoscope, 129:1949-1953, 2019.

Longevity of Implantable Pulse Generators in Bilateral Deep Brain Stimulation for Movement Disorders

Deep brain stimulation (DBS) is a well-established therapy for otherwise intractable movement disorders. Thus far, most patients receive nonrechargeable implantable pulse generators (IPG). Eventually, another intervention to replace the IPG is inevitable. We assessed IPG model-specific differences in longevity in patients planned for IPG replacement. Also, we evaluated the influence of the total electric energy delivered (TEED), the amount of previous IPG replacements, and previous IPG model changes on the longevity. We collected the demographic data and DBS settings of 47 patients (19 with Parkinson's disease, 7 with essential tremor, and 21 with dystonia) that were treated either with Medtronic's Kinetra® (N = 16) or Activa® PC (N = 31). Statistical analysis was performed using Mann-Whitney U test and Spearman's rank correlation. Battery longevity was shorter in the Activa PC than in the Kinetra (40.16 ± 15.22 vs. 70.35 ± 24.45 months; p < 0.001). Further analysis showed an inverse correlation of the longevity to TEED (r = -0.529; p < 0.001) and the number of previous IPG replacements (r = -0.588; p < 0.001). Furthermore, patients with more frequent replacements had higher TEED (r = 0.501; p < 0.001) and patients, whose Kinetra was replaced with the Activa PC before, had shorter IPG longevity (28.36 ± 9.82 vs. 45.78 ± 14.19 months; p = 0.006). Our findings imply that IPG longevity is shorter in the Activa PC compared to the Kinetra. Higher TEED and more frequent IPG replacements might reduce IPG longevity.