MR Safety: Active Implanted Electronic Devices

New implanted medical devices continue to be made available for treatment of medical conditions. Many recipients can benefit from the diagnostic power of MR imaging. Provisions must be made to determine if these patients can be safely scanned. Metal-containing devices can be considered either MR unsafe or conditional. It is essential that all components of an implanted system are completely and accurately identified, with the most restrictive MR safety condition dictating the scanning approach. MR safety considerations for major classes of implanted devices are discussed, recognizing that there have been reports of serious device-related MR safety incidents.

Breast reconstruction in a patient with an implanted deep brain stimulator

Deep brain stimulators (DBSs) are sometimes used to treat refractory movement disorders such as Parkinson's disease. When DBSs are implanted in a subcutaneous pocket in the chest region, breast reconstruction becomes a challenge because monopolar electrocautery can lead to DBS dysfunction or brain tissue damage caused by heat. We report a patient with a DBS who underwent one-stage implant-based breast reconstruction. We switched off the DBS before surgery and used monopolar electromagnetic cautery with minimum power settings to undermine the subcutaneous pocket for the breast implant. The DBS was switched back on immediately after completion of the surgery. The patient's postoperative recovery was uneventful with the DBS fully functional.

Thoracic surgery in patients with an implanted neurostimulator device

Movement disorders such as Parkinson's disease are increasingly treated with deep brain stimulators. Being implanted in a subcutaneous pocket in the chest region, thoracic surgical procedures can interfere with such devices, as they are sensible to external electromagnetic forces. Monopolar electrocautery can lead to dysfunction of the device or damage of the brain tissue caused by heat. We report a series of 3 patients with deep brain stimulators who underwent thoracic surgery. By turning off the deep brain stimulators before surgery and avoiding the use of monopolar cautery, electromagnetic interactions were avoided in all patients.

Preanesthetic evaluation of a patient with a deep brain stimulator: a practical guide and checklist for patient safety

As the patient population with deep brain stimulators grows, medical personnel need to be comfortable managing these patients because they will likely encounter them in practice. Caring for a patient with a deep brain stimulator during surgery or a procedure requires technical knowledge of the device and its possible interactions in order to take the correct precautionary measures. Here we discuss the key issues and questions that should be covered in every preanesthetic evaluation visit of a patient with a deep brain stimulator along with an evaluation checklist.

Anaesthetic management of shoulder arthroscopic repair in Parkinson's disease with deep brain stimulator

We describe the anaesthetic management of arthroscopic repair for complete rotator cuff tear of shoulder in a 59-year-old female with Parkinson's disease (PD) with deep brain stimulator (DBS) using a combination of general anaesthesia with interscalene approach to brachial plexus block. The DBS consists of implanted electrodes in the brain connected to the implantable pulse generator (IPG) normally placed in the anterior chest wall subcutaneously. It can be programmed externally from a hand-held device placed directly over the battery stimulator unit. In our patient, IPG with its leads was located in close vicinity of the operative site with potential for DBS malfunction. Implications of DBS in a patient with PD for shoulder arthroscopy for anaesthesiologist are discussed along with a brief review of DBS.

Amygdalohippocampectomy for epilepsy in a patient with prior ipsilateral deep brain stimulator lead placement

In light of failed medical therapy for movement disorders, the use of deep brain stimulation (DBS) has increased the last two decades. Many complications may transpire; however, to our knowledge, the literature does not mention the phenomena of brain shift from a second unrelated neurosurgical procedure and its theoretical effect on lead displacement and lead function. We present a patient with a left sided DBS for essential tremor and subsequent left amygdalohippocampectomy for temporal lobe epilepsy with minimal radiographic distortion of the DBS lead and without clinical or functional complications. A 47-year-old woman presented with bitemporal epilepsy secondary to a brain injury acquired in childhood in addition to a comorbid bilateral essential tremor, both refractory to medical intervention. A successful left-sided DBS placement was performed with satisfactory resolution of her essential tremor. The patient subsequently developed deterioration of seizure control, becoming refractory to anti-epileptic medications, requiring surgical intervention. A left-sided selective amygdalohippocampectomy and techniques to minimize brain shift were performed without complications. Postoperative imaging suggested minimal distortion of the DBS lead. This did not correspond with reemergence of her essential tremor, implying that the lead maintained functional utility. Brain shift secondary to a craniotomy may cause DBS lead displacement. This phenomenon should be considered when planning operative approaches and can be limited by selective resections. With the growing propensity for placement of DBS leads and the risk of lead displacement, it is important to consider operative approaches to minimize brain shift.