Rechargeable Implantable Pulse Generators Research Articles

Complications of Spinal Cord Stimulators-A Comprehensive Review Article.

Spinal cord stimulation has been increasing in influence as an option to regulate pain, especially in the chronic pain patient population. However, even with the numerous changes made to this technology since its inception, it is still prone to various complications such as hardware issues, neurological injury/epidural hematoma, infections, and other biological concerns. The purpose of this article is to thoroughly review and evaluate literature pertaining to the complications associated with percutaneous spinal cord stimulation. Lead migration is generally the most common complication of percutaneous spinal cord stimulation; however, recent utilization of various anchoring techniques has been discussed and experienced clinical success in decreasing the prevalence of lead migration and lead fractures. With newer high-frequency systems gaining traction to improve pain management and decrease complications as compared to traditional systems, rechargeable implantable pulse generators have been the preferred power source. However, recent findings may suggest that these rechargeable implantable pulse generators do not significantly increase battery life as much as was proposed. Intraoperative neuromonitoring has seen success in mitigating neurological injury postoperatively and may see more usage in the future through more testing. Though the occurrence of infection and biological complications, including dural puncture and skin erosion, has been less frequent over time, they should still be treated in accordance with established protocols. While many complications can arise following percutaneous spinal cord stimulator implantation, the procedure is less invasive than open implantation and has seen largely positive patient feedback. Hardware complications, the more common issues that can occur, rarely indicate a serious risk and can generally be remedied through reoperation. However, less common cases such as neurological injury, infections, and biological complications require prompt diagnosis to improve the condition of the patient and prevent significant damage.

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.

A single-center, open-label trial on convenience and complications of rechargeable implantable pulse generators for spinal cord stimulation: The Recharge Pain Trial

Rechargeable implantable pulse generators (r-IPGs) have been available for spinal cord stimulation (SCS) claiming to offer a longer service life but demanding continuous monitoring and regular recharging by the patients. The aim of the study (DRKS00021281; Apr 7th, 2020) was to assess the convenience, safety, and acceptance of r-IPGs and their effect on patient lives under long-term therapy. Standardized questionnaires were sent to all chronic pain patients with a r-IPG at the time of trial. Primary endpoint was the overall convenience of the charging process on an ordinal scale from “very hard” (1 point) to “very easy” (5 points). Secondary endpoints were charge burden (min/week), rates of user confidence and complications (failed recharges, interruptions of therapy). Endpoints were analyzed for several subgroups. Data sets n = 40 (42% return rate) were eligible for analysis. Patient age was 57.2 ± 12.6 (mean ± standard deviation) years with the r-IPG being implanted for 52.1 ± 32.6 months. The overall convenience of recharging was evaluated as “easy” (4 points). The charge burden was 112.7 ± 139 min/week. 92% of the patients felt confident recharging the neurostimulator. 37.5% of patients reported failed recharges. 28.9% of patients experienced unintended interruptions of stimulation. Subgroup analysis only showed a significant impact on overall convenience for different models of stimulators (p < 0.05). Overall, SCS patients feel confident handling a r-IPG at high rates of convenience and acceptable effort despite high rates of usage-related complications. Further technical improvements for r-IPGs are needed.

Patient-Reported Satisfaction with Using a Rechargeable 10 kHz Spinal Cord Stimulation Device

Chronic pain is a common clinical condition and is frequently treated with a variety of medications, but pharmacotherapy is oftentimes not the optimal long-term treatment option. Safe and effective long-term pain relief for trunk and limb pain is available using high-frequency spinal cord stimulation at 10 kHz (10 kHz SCS), which is delivered using a rechargeable implantable pulse generator (IPG). Although rechargeable devices have been shown to reduce patient risk and overall cost by eliminating the need for periodic surgeries to replace depleted non-rechargeable IPGs, there is little published evidence that rechargeable technology is practical and convenient for patients, especially in the context of 10 kHz SCS. This analysis of real-world patients implanted with 10 kHz SCS devices was undertaken using patient data from an industry-maintained database to investigate whether there was a substantial burden associated with rechargeable SCS and the degree of patient satisfaction or dissatisfaction with 10 kHz SCS. This study included 10,391 men and women who were implanted with 10 kHz SCS devices to treat chronic pain of the trunk and/or limbs. They received stimulation for a median of 361 days (180-1550 days), and 65.48% had previous spine surgery. In this patient sample, most patients were satisfied with the efficacy of 10 kHz SCS, including 77% who would repeat the procedure and 71% who would recommend it to other patients with similar pain. In regards to IPG recharging, 70% were satisfied or very satisfied and 19% were neutral, and a majority of patients recharged their device daily for 30 to 60 minutes. These results indicate most patients do not find IPG recharging inconvenient or burdensome. In addition, IPG recharging is not a barrier to the majority of patients benefitting from 10 kHz SCS for long-term pain relief.

Recharge PSYCH: A Study on Rechargeable Implantable Pulse Generators in Deep Brain Stimulation for Psychiatric Disorders

Rechargeable implantable pulse generators (r-IPGs) for deep brain stimulation (DBS) promise longer battery life and fewer replacement surgeries versus non-rechargeable systems. Long-term data on the effects of recharging in patients who received DBS for psychiatric indications is limited. The Recharge PSYCH trial is the first study that included DBS patients with psychiatric disorders treated with different r-IPG models. Standardized questionnaires were sent to all psychiatric DBS patients with an r-IPG implanted at the time of the study. The primary endpoint was convenience of recharging. Secondary endpoints were rate of user confidence and rate of usage-related complications, as well as charge burden (defined as minutes per week needed to recharge). Data sets of n= 21 patients were eligible for data analysis. At the time of the survey patients were implanted with the r-IPG for a mean 31.8±22.4months. Prior to being implanted with an r-IPG, patients had undergone a median of 3 IPG replacements. The overall convenience of the charging process was rated as "easy" with a median of 8.0 out of 10.0 points. 33.3% of patients experienced situations in which the device could not be successfully recharged. In 38.1% of patients, therapy with the r-IPG was interrupted unintentionally. The average charge burden was 286±22.4minutes per week. Patients with psychiatric disorders rated the recharging process as "easy", but with a significantly higher charge burden and usage-related complication rates compared to published data on movement disorder DBS patients.

A Longitudinal Magnetoencephalographic Study of the Effects of Deep Brain Stimulation on Neuronal Dynamics in Severe Anorexia Nervosa.

Anorexia Nervosa (AN) is a debilitating psychiatric disorder characterized by the relentless pursuit of thinness, leading to severe emaciation. Magnetoencephalography (MEG)was used to record the neuronal response in seven patients with treatment-resistant AN while completing a disorder-relevant food wanting task. The patients underwent a 15-month protocol, where MEG scans were conducted pre-operatively, post-operatively prior to deep brain stimulation (DBS) switch on, twice during a blind on/off month and at protocol end. Electrodes were implanted bilaterally into the nucleus accumbens with stimulation at the anterior limb of the internal capsule using rechargeable implantable pulse generators. Three patients met criteria as responders at 12 months of stimulation, showing reductions of eating disorder psychopathology of over 35%. An increase in alpha power, as well as evoked power at latencies typically associated with visual processing, working memory, and contextual integration was observed in ON compared to OFF sessions across all seven patients. Moreover, an increase in evoked power at P600-like latencies as well as an increase in γ-band phase-locking over anterior-to-posterior regions were observed for high- compared to low-calorie food image only in ON sessions. These findings indicate that DBS modulates neuronal process in regions far outside the stimulation target site and at latencies possibly reflecting task specific processing, thereby providing further evidence that deep brain stimulation can play a role in the treatment of otherwise intractable psychiatric disorders.

Deep Brain Stimulation of the Nucleus Accumbens in Severe Enduring Anorexia Nervosa: A Pilot Study.

IntroductionAnorexia nervosa (AN) is one of the most debilitating psychiatric disorders, becoming severe and enduring in a third of cases; with few effective treatments. Deep brain stimulation is a reversible, adjustable neurosurgical procedure that has been gaining ground in psychiatry as a treatment for depression and obsessive–compulsive disorder, yet few studies have investigated AN. Abnormal eating behavior and the compulsive pursuit of thinness in AN is, in part, a consequence of dysfunction in reward circuitry and the nucleus accumbens (NAcc) is central to reward processing.MethodsPhase 1 prospective open-label pilot study of seven individuals with severe enduring AN. Electrodes were implanted bilaterally into the NAcc with stimulation at the anterior limb of the internal capsule using rechargeable implantable pulse generators. The protocol of 15 months included 12 months of deep brain stimulation incorporating two consecutive, randomized blind on-off fortnights 9 months after stimulation onset. The primary objectives were to investigate safety and feasibility, together with changes in eating disorder psychopathology.ResultsFeasibility and safety was demonstrated with no serious adverse events due to deep brain stimulation. Three patients responded to treatment [defined as > 35% reduction in Eating Disorders Examination (EDE) score at 12 months] and four patients were non-responders. Responders had a statistically significant mean reduction in EDE scores (50.3% reduction; 95% CI 2.6–98.2%), Clinical Impairment Assessment (45.6% reduction; 95% CI 7.4–83.7%). Responders also had a statistically significant mean reduction in Hamilton Depression Scale, Hamilton Anxiety Scale and Snaith-Hamilton pleasure scale. There were no statistically significant changes in Body Mass Index, Yale-Brown-Cornell Eating Disorder Scale, Yale-Brown Obsessive–Compulsive Scale and World Health Organization Quality of Life Psychological subscale.ConclusionThis study provides some preliminary indication that deep brain stimulation to the NAcc. Might potentially improve some key features of enduring AN. In this small study, the three responders had comorbid obsessive-compulsive disorder which predated AN diagnosis. Future studies should aim to further elucidate predictors of outcome.Clinical Trial Registration[www.ClinicalTrials.gov], identifier [Project ID 128658].

Fixed-Life or Rechargeable Battery for Deep Brain Stimulation: Preference and Satisfaction in Chinese Patients With Parkinson's Disease.

Introduction: DBS is a widely used therapy for PD. There is now a choice between fixed-life implantable pulse generators (IPGs) and rechargeable IPGs, each having advantages and disadvantages. This study aimed to evaluate the preference and satisfaction of Chinese patients with Parkinson's disease (PD) who were treated with deep brain stimulation (DBS).Materials and Methods: Two hundred and twenty PD patients were treated with DBS and completed a self-reported questionnaire to assess their long-term satisfaction and experience with the type of battery they had chosen and the key factors affecting these choices. The survey was performed online and double-checked for completeness and accuracy.Results: The median value of the postoperative duration was 18 months. The most popular way for patients to learn about DBS surgery was through media (79/220, 35.9%) including the Internet and television programs. In total, 87.3% of the DBS used rechargeable IPGs (r-IPG). The choice between rechargeable and non-rechargeable IPGs was significantly associated with affordability ( = 19.13, p < 0.001). Interestingly, the feature of remote programming significantly affected patients' choices between domestic and imported brands ( = 16.81, p < 0.001). 87.7% of the patients were satisfied with the stimulating effects as well as the implanted device itself. 40.6% of the patients with r-IPGs felt confident handling devices within 1 week after discharge. More than half of the patients checked their batteries every week. The mean interval for battery recharge was 4.3 days. 57.8% of the patients spent around 1 h recharging, and 71.4% of them recharged the battery independently.Conclusions: Most patients were satisfied with their choice of IPGs. The patients' economic status and the remote programming function of the device were the two most critical factors in their decision. The skill of recharging the IPG was easy to master for most patients.

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.

Fixed-Life or Rechargeable Battery for Deep Brain Stimulation: A Prospective Long-Term Study of Patient’s Preferences

Introduction: Deep brain stimulation (DBS) is an established treatment for movement disorders. We have previously shown that in our practice, the majority of adult patients prefer fixed-life implantable pulse generators (IPGs), although rechargeable batteries are increasingly used. The aim of this study was to evaluate patients’ long-term satisfaction with their choice of battery and factors that influence their decision. Methods: Thirty patients with DBS were given a questionnaire to assess long-term satisfaction and experience with the type of battery they had chosen. Results: Twenty-six patients completed the survey. The mean age was 67.7 ± 7.3 years, and mean follow-up was 18.0 ± 7.2 months. The indications for DBS were Parkinson’s disease (76.9%), tremor (11.5%) and dystonia (11.5%). Eleven patients (42.5%) had chosen the rechargeable battery. All patients were still happy with their choices and would not change the type of battery if they had the chance to do so. However, in patients who chose the fixed-life battery, concern about the size of battery rose from 6.7% pre-operatively to 60% on long-term post-operative follow-up. In patients who chose the rechargeable battery, concern about the need to recharge the battery did not change, remaining low postoperatively. Interestingly, even though the main reason cited for choosing the fixed-life battery was the convenience and concern about forgetting to recharge the battery, patients who had chosen a rechargeable IPG did not experience this problem. Conclusion: Patients and caregivers should be involved in the choice of battery, as each type of IPG has its own advantages and disadvantages. Long-term evaluation of patient’s experience and satisfaction with battery of choice revealed that size of the IPG, need for further replacement surgeries and need for recharging remain matters of major concern. Although preoperatively often underestimated, the size of the battery seems to be an important factor in long-term satisfaction.

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.

Changes in peripheral and central sensitization in patients undergoing occipital nerve stimulation.

Central sensitization and impaired conditioned pain modulation (CPM) response have been reported to contribute to migraine progression. Migraine patients can present with allodynia possibly attributed to increased sensitivity of peripheral ends of nociceptors with both peripheral and central sensitization. Occipital nerve stimulation (ONS) works by stimulating the distal branches of C1, C2 and C3 possibly altering the nociceptive traffic to the trigemino-cervical complex, brainstem and supranuclear connections. This observational study explores peripheral and central sensitization in patients undergoing percutaneous ONS. Following local regulatory approval, 13 patients undergoing ONS with dual Octrode 90 cm leads and rechargeable implantable pulse generator (IPG) (St Jude) were recruited to have quantitative sensory testing (QST) pre- and post-procedure 2 weeks, 1, 3, 6 and 12 months. Patients with intractable migraine demonstrated impaired CPM (mean baseline pressure pain thresholds (PPTs): 61.98 kPa vs 48.01 kPa cuff inflated) prior to ONS, reverting to an efficient CPM response within 2 weeks following ONS implant (68.9 kPa vs 104.5 kPa cuff inflated) and continuing positively over the next 12 months. In contrast, no statistical difference was observed in PPTs. This is the first reported observation highlighting the effects on central sensitization following ONS. A consistent and sustained improvement in CPM was observed in contrast to PPT's where there was no difference. Normalisation of the CPM response following ONS indicates that the treatment may reduce central sensitization in the migraine population.

Patient Experience with Rechargeable Implantable Pulse Generator Deep Brain Stimulation for Movement Disorders

Background/Aims: Nonrechargeable deep brain stimulation implantable pulse generators (IPGs) for movement disorders require surgical replacement every few years due to battery depletion. Rechargeable IPGs reduce frequency of replacement surgeries and inherent risks of complications but require frequent recharging. Here, we evaluate patient experience with rechargeable IPGs and define predictive characteristics for higher satisfaction. Methods: We contacted all patients implanted with rechargeable IPGs at a single center in a survey-based study. We analyzed patient satisfaction with respect to age, diagnosis, target, charging duration, and body mass index. We tabulated hardware-related adverse events. Results: Dystonia patients had significantly higher satisfaction than Parkinson’s disease patients in recharging, display, programmer, and training domains. Common positive responses were “fewer surgeries” and “small size.” Common negative responses were “difficulty finding the right position to recharge” and “need to recharge every day.” Hardware-related adverse events occurred in 21 of 59 participants. Conclusion: Patient experience with rechargeable IPGs was largely positive; however, frustrations with recharging and adverse events were common. Dystonia diagnosis was most predictive of high satisfaction across multiple categories, potentially related to expected long disease duration with need for numerous IPG replacements.

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.

Trial Versus No Trial of Spinal Cord Stimulation for Chronic Neuropathic Pain: Cost Analysis in United Kingdom National Health Service

ObjectivesThe aim of the current project was to evaluate the spinal cord stimulation (SCS) screening trial success rate threshold to obtain the same cost impact across two identical sets of patients following either a prolonged screening trial prior to implantation strategy or a full implant without a screening trial.Materials and MethodsA cost impact analysis was carried out from a health care perspective and considered trial to implant rates reported in the literature. Items of resource use were costed using national averages obtained from the National Health Service (NHS) reference cost data base. Cost components were added up to derive total patient level costs for the NHS. Only the costs associated with the screening trial procedures and devices were considered.ResultsThe most conservative of our estimates suggest that a failure rate of less than 15% is cost saving to the NHS. A failure rate as high as 45% can also be cost saving if the less expensive nonrechargeable SCS devices are used. All the thresholds observed represent a considerably higher screening failure rate than that reported in the latest randomized controlled trials (RCTs) of SCS. A trial to implant ratio of 91.6% could represent savings between £16,715 (upper bound 95% CI of rechargeable implantable pulse generator [IPG] cost) and £246,661 (lower bound 95% CI of nonrechargeable IPG cost) per each 100 patients by adopting an implantation only strategy.ConclusionsConsiderable savings could be obtained by adopting an implantation strategy without a screening trial. It is plausible that accounting for other factors, such as complications that can occur with a screening trial, additional savings could be achieved by choosing a straight to implant treatment strategy. Nevertheless, additional evidence is warranted to support this claim.

Rechargeable Stimulators in Deep Brain Stimulation for Obsessive-Compulsive Disorder: A Prospective Interventional Cohort Study

From 1999 onwards, deep brain stimulation (DBS) has been proposed as an alternative to capsulotomy in refractory cases of obsessive-compulsive disorder (OCD). Although rechargeable implantable pulse generators (rIPGs) have been used extensively in DBS for movement disorders, there are no reports on rIPGs in patients with a psychiatric DBS indication, and even possible objections to their use. We aim to evaluate rIPGs in OCD in terms of effectiveness, applicability, safety, and need for IPG replacement. In this prospective before-after study recruiting from 2007 until 2012, OCD patients requiring at least one IPG replacement per 18 months were proposed to have a rIPG implanted at the next IPG depletion. OCD severity was the primary outcome. Ten patients were analyzed. Psychiatric symptoms and global functioning remained stable in the two years after as compared to the two years before rIPG implantation. Over the same period, the prescribed OCD medication doses did not increase and the DBS stimulation parameters were largely unaltered. Until the end of the follow-up (mean 4¾ years; maximum seven years), the DBS-related surgery frequency decreased and there were no rIPG replacements. During the first few weeks after implantation, two patients obsessively checked the rIPG, but afterwards there were no signs of compulsively checking or recharging the rIPG. Two patients experienced rIPG overdischarges (five occurrences in total). This is the first report on rIPGs in DBS for OCD patients. The use of rIPGs in this population appears to be effective, applicable, and safe and diminishes the need for IPG replacements.

Technological Advances in Deep Brain Stimulation.

Functional and stereotactic neurosurgery has always been regarded as a subspecialty based on and driven by technological advances. However until recently, the fundamentals of deep brain stimulation (DBS) hardware and software design had largely remained stagnant since its inception almost three decades ago. Recent improved understanding of disease processes in movement disorders as well clinician and patient demands has resulted in new avenues of development for DBS technology. This review describes new advances both related to hardware and software for neuromodulation. New electrode designs with segmented contacts now enable sophisticated shaping and sculpting of the field of stimulation, potentially allowing multi-target stimulation and avoidance of side effects. To avoid lengthy programming sessions utilising multiple lead contacts, new user-friendly software allows for computational modelling and individualised directed programming. Therapy delivery is being improved with the next generation of smaller profile, longer-lasting, re-chargeable implantable pulse generators (IPGs). These include IPGs capable of delivering constant current stimulation or personalised closed-loop adaptive stimulation. Post-implantation Magnetic Resonance Imaging (MRI) has long been an issue which has been partially overcome with 'MRI conditional devices' and has enabled verification of DBS lead location. Surgical technique is considering a shift from frame-based to frameless stereotaxy or greater role for robot assisted implantation. The challenge for these contemporary techniques however, will be in demonstrating equivalent safety and accuracy to conventional methods. We also discuss potential future direction utilising wireless technology allowing for miniaturisation of hardware.

Rechargeable occipital nerve stimulator systems: A patient satisfaction study

Introduction. Cluster headache is a disabling severe headache syndrome, with a prevalence of 0.12%. Occipital nerve stimulation (ONS) is a recognized treatment for medically intractable cluster headache, composed of two electrodes in contact with the greater occipital nerves and connected to an Implantable Pulse Generator (IPG). The battery can be non-rechargeable or rechargeable, which has a longer total lifespan. This is, to our knowledge, the largest patient survey to examine the level of satisfaction with rechargeable batteries. Methodology. Using the ONS database at the National Hospital for Neurology and Neurosurgery, London we identified 100 patients who have had rechargeable systems implanted. We used a patient satisfaction questionnaire, developed with some questions adapted from McAuley et al. regarding rechargeable IPGs for spinal cord stimulation. Results. Ninety-two out of the 100 patients consented to participate. Of them, 68 patients (74%) found recharging the battery convenient and 81 (88%) found that the amount of inconvenience associated with recharging worth the benefit they receive from the stimulation. Of 48 patients who had a non-rechargeable battery before the current rechargeable one, 37 (84%) stated preferring the current rechargeable. Discussion. The results indicate a positive general outcome of ONS with rechargeable battery. We believe that this survey gives a reliable estimation of the outcome considering the large size of the sample and the very high rate of patients’ compliance to answer our questionnaire. Conclusions. These data suggest that ONS with rechargeable IPG may be considered the system of choice for patients undergoing ONS implant.

Prediction of Implantable Pulse Generator Longevity in Deep Brain Stimulation: Limitations and Possible Solutions in Clinical Practice

Background: Deep brain stimulation (DBS) is used in the treatment of movement disorders, chronic pain and certain neuropsychiatric conditions. Its effect is achieved through local stimulation of specific targets of the brain. Electrical pulses are delivered at settings that can be tailored to provide optimum symptom control. DBS is powered by an implantable pulse generator (IPG). These IPGs do not have an indefinite lifespan and will eventually become depleted. Therefore, regular checks are carried out to monitor the IPG’s power status. Objective: To evaluate the utility of computer-based prediction of IPG longevity in patients with DBS devices by imputing the device’s settings. Patients: Eighty-two IPGs in 47 consecutive patients were studied comparing the actual longevity of the IPGs with their predicted longevity using a computer-based calculator. Results: Our study showed that the predicted longevities were too different from actual longevities to have a role in clinical practice. The time difference varied by more than 12 months in some cases, with a correlation coefficient of <0.68. There were multiple reasons for this. Conclusion: The longevities of IPGs could not be predicted accurately enough for the computer-based calculator to have a role in clinical practice or the proactive scheduling of IPG replacement. However, rechargeable IPGs may help avoid premature replacements and battery depletions.