A Successful Course of Electroconvulsive Therapy in a Patient With Epilepsy and a Posterior Fossa Titanium Plate
We write to describe the case of a 49-year-old man with posterior titanium intracranial mesh who has safely undergone a course of electroconvulsive therapy (ECT). The patient was originally referred to the service for chronic, severe treatment-refractory depression and suicidality, with a history of serious suicide attempts. His history was notable for symptomatic Arnold-Chiari I malformation, for which he underwent neurosurgical decompression with titanium plate placement in the posterior fossa. As a complication of the surgery, the patient developed a temporal lobe seizure disorder, characterized by motor automatisms and loss of memory, successfully controlled with lamotrigine and gabapentin. Before ECT initiation, neurosurgical consultation was pursued to determine risks associated with electrical stimulation with a titanium intracranial plate, which were determined to be minimal with adjusted bifrontal lead placement equidistant and furthest from the plate, consistent with recommendations by Ling et al1 and Mortier et al.2 Although not possible to completely taper antiepileptics, lamotrigine and gabapentin doses were lowered to minimize seizure impedance. Bifrontal ECT was initiated thrice weekly using a MECTA Spectrum 5000Q machine, with the following settings (pulse width, 0.5 milliseconds; frequency, 40 Hz; duration, 8 seconds; current, 800 mA; energy, 45.4 J) with typical convulsion durations of 25 to 40 seconds and typical seizure durations of 30 to 45 seconds. The patient underwent a total of 24 ECT treatments with successful response and no adverse effects.
As clinicians treat an increasing number of patients with ECT and comorbid complex medical conditions, documenting such cases is imperative for optimizing safe care. Treating patients with both intracranial objects and comorbid seizure disorders offers a clinical challenge rarely discussed in the literature. Both conditions require additional consideration of pharmacologic and anatomic adjustments. Electroconvulsive therapy treatment in patients with epilepsy has been well documented and may stabilize the underlying seizure disorder due to an ECT-related increase in the seizure threshold. The clinical challenge therefore lies in balancing the prophylactic need for antiepileptics with minimizing the prevention of induced seizures. Intracranial metallic objects however pose the theoretical risks of material (and surrounding brain tissue) heating or alterations in current distribution or conductance. Although the object's material (and inherent electrical resistivity) dictates the degree of potential temperature change, studies have demonstrated the energy used in ECT to be too low to cause significant heating of metallic plates, especially titanium (the material used in most neurosurgical implants at this time), which is principally inert.2–4 In addition, given the exponential fall in total energy with increasing distance, lead placement that maximizes distance from the intracranial objects further decreases theoretical risk of heat and current shunting.2,5 We therefore suggest that in patients with intracranial objects and comorbid seizure disorders, antiepileptics should be safely minimized to limit energy delivered and intracranial objects be clearly located to optimally adjust lead placement. Although there have been previously published cases of successful ECT treatment with intracranial metallic objects and comorbid epilepsy, this is the first, to our knowledge, to document safe treatment with ECT with titanium mesh in the posterior fossa.