Subclavicular and Suprascapular Placement of Response Neurostimulator Generator: Two Unique Cases

Introduction: The Response Neurostimulation (RNS) system is a treatment modality for medical refractory epilepsy that monitors the electrical signals of the brain and responds to electrical signals that may indicate the onset of seizure activity. The system responds with stimulation which is thought to impede the progression of a potential seizure. The RNS system consists of the depth electrode and/or cortical strip electrode in the seizure focus connected to a neurostimulator. The neurostimulator is placed within the skull to minimize system noise. However, there are cases in which placing the neurostimulator in the skull may not be ideal due to obstruction of future treatment/imaging or wound healing issues with the scalp.

Methods: Two different locations were trialed in two separate patients for the placement of the neurostimulator. The first patient required further treatment for a high-grade glioma and the location of the neurostimulator would diminish the effectiveness of radiation treatment and hinder the quality of future imaging. It was decided that the patient would have the generator placed in a subclavicular position. The second patient had challenges with wound healing secondary to a thin scalp causing erosion and the need for explantation of the first system. After discussion, the neurostimulator was placed in a suprascapular/trapezius position.

Results: Neurostimulator placement in non-traditional locations such as the subclavicular and suprascapular/trapezius positions provided electrocorticography with great signal and minimal noise contrary to previous assumptions.

Conclusion : These findings are encouraging because they highlight the possibility of neurostimulators being placed in unconventional locations for patients who already receive great benefits from the RNS system but have potential complications with placing the neurostimulator within the skull. These two patients ultimately had generator placements in the subclavicular and suprascapular/trapezius positions but maintained excellent electrocorticography and benefited from the RNS system.