Electromagnetic interference of GSM mobile phones with the implantable deep brain stimulator, ITREL-III

BACKGROUND: The purpose was to investigate mobile phone interference with implantable deep brain stimulators by means of 10 different 900 Mega Hertz (MHz) and 10 different 1800 MHz GSM (Global System for Mobile Communications) mobile phones. METHODS: All tests were performed in vitro using a phantom especially developed for testing with deep brain stimulators. The phantom was filled with liquid phantom materials simulating brain and muscle tissue. All examinations were carried out inside an anechoic chamber on two implants of the same type of deep brain stimulator: ITREL-III from Medtronic Inc., USA. RESULTS: Despite a maximum transmitted peak power of mobile phones of 1 Watt (W) at 1800 MHz and 2 W at 900 MHz respectively, no influence on the ITREL-III was found. Neither the shape of the pulse form changed nor did single pulses fail. Tests with increased transmitted power using CW signals and broadband dipoles have shown that inhibition of the ITREL-III occurs at frequency dependent power levels which are below the emissions of GSM mobile phones. The ITREL-III is essentially more sensitive at 1800 MHz than at 900 MHz. Particularly the frequency range around 1500 MHz shows a very low interference threshold. CONCLUSION: These investigations do not indicate a direct risk for ITREL-III patients using the tested GSM phones. Based on the interference levels found with CW signals, which are below the mobile phone emissions, we recommend similar precautions as for patients with cardiac pacemakers: 1. The phone should be used at the ear at the opposite side of the implant and 2. The patient should avoid carrying the phone close to the implant

Temperature measurement on neurological pulse generators during MR scans

According to manufacturers of both magnetic resonance imaging (MRI) machines, and implantable neurological pulse generators (IPGs), MRI is contraindicated for patients with IPGs. A major argument for this restriction is the risk to induce heat in the leads due to the electromagnetic field, which could be dangerous for the surrounding brain parenchyma. The temperature change on the surface of the case of an ITREL-III (Medtronic Inc., Minneapolis, MN) and the lead tip during MRI was determined. An anatomical realistic and a cubic phantom, filled with phantom material mimicking human tissue, and a typical lead configuration were used to imitate a patient who carries an IPG for deep brain stimulation. The measurements were performed in a 1.5 T and a 3.0 T MRI. 2.1°C temperature increases at the lead tip uncovered the lead tip as the most critical part concerning heating problems in IPGs. Temperature increases in other locations were low compared to the one at the lead tip. The measured temperature increase of 2.1°C can not be considered as harmful to the patient. Comparison with the results of other studies revealed the avoidance of loops as a practical method to reduce heating during MRI procedures

Predictability of thermo-lesions using electrodes for deep brain stimulation - an in vitro study

<p>Abstract</p> <p>Background</p> <p>Typically, electrodes for Deep Brain Stimulation (DBS) are used for chronic stimulation. However, there are conditions where this therapy has to be discontinued. In such cases using the DBS electrodes as a tool for thermo-lesioning (coagulation) could be used for an alternative treatment. The aim of this study was to determine if it is possible to generate coagula with a predictable geometry and to define their dimensions as a function of power and time in an in vitro model (egg white at room temperature). Furthermore, we tested if repetitive (cumulative) coagulation has an impact on the overall form and size of the clot.</p> <p>Findings</p> <p>Coagulation-growth was achieved as a function of power and duration of coagulation; reproducible well-formed thermocoagulations could be achieved. When using two adjacent electrodes a power range between 1.25 Watt and 2.00 Watt resulted in homogenous ovoid coagula. After two minutes of coagulation the clots reached a maximum in size and further growth could not be achieved. It was also possible to increase the size of a preformed clot by repetitive coagulation either by increasing the power level or the duration of the coagulation process.</p> <p>Conclusions</p> <p>We could show that it is possible to obtain predictable coagula in-vitro when using DBS electrodes for thermocoagulation even though they have not been developed for that specific purpose. However, until in-vivo safety and efficacy of DBS electrodes for ablation purposes is properly assessed, only approved electrodes should be used for brain ablation.</p

Subacute brainstem angioencephalopathy: favorable outcome with anticoagulation therapy

We present a patient who developed progressive neurological disease caused by lesions histologically compatible with those observed in subacute brainstem angioencephalopathy. The patient was treated with low-molecular weight heparin, and treatment response was monitored clinically and with MRI. Anticoagulation therapy stopped progression of the neurological deficit and led to improvement of MRI findings. This report further supports the existence of subacute brainstem angioencephalopathy as a characteristic disease entity and gives insight into possible therapeutic approach with anticoagulation treatment

135 A Comparison of Outcomes Between Deep Brain Stimulation Under General Anesthesia Versus Conscious Sedation With Awake Evaluation

International audienceINTRODUCTION: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) for the management of motor symptoms of Parkinson disease (PD) is typically performed under conscious sedation with awake evaluation during intraoperative physiologic testing. However, developments in surgical techniques now allow for subjects to be asleep during the procedure using general anesthesia. Previously reported long-term outcomes of subjects who underwent STN-DBS under general anesthesia demonstrated postoperative safety and efficacy out to 1 year. In this study, we examine outcomes between subjects undergoing the STN-DBS procedure who used general anesthesia vs those using conscious sedation with awake evaluation as part of the ongoing VANTAGE clinical trial. METHODS: VANTAGE is a prospective, multicenter, nonrandomized, open-label interventional trial, sponsored by Boston Scientific Corporation. The trial assesses motor improvement in subjects with moderate-to-severe PD following bilateral STN-DBS. Assessments include motor scores such as Unified Parkinson's Disease Rating Scale (UPDRS) and quality-of-life measurements such as PDQ-39. Forty subjects were implanted bilaterally with the Vercise DBS System (Boston Scientific Corporation) at 6 European centers. Of these, 19 (47%) underwent the DBS procedure under general anesthesia. RESULTS: Analysis of both study groups did not indicate a statistically significant difference in motor function outcomes. However, subjects utilizing general anesthesia were found not to display motor function outcomes that were necessarily clinically inferior to those consciously sedated with awake evaluation. Sample size and variation in baseline differences in selected subjects may have contributed to these final results, because a tendency for subjects undergoing general anesthesia to report an improvement in motor function similar to or better than those consciously sedated (vs baseline) was observed. CONCLUSION: No inferiority in clinical outcomes was observed in subjects that underwent general anesthesia vs those that were consciously sedated with awake evaluation