Magnetically Guided Catheters, Micro- and Nanorobots for Spinal Cord Stimulation.

Spinal cord stimulation (SCS) is an established treatment for refractory pain syndromes and has recently been applied to improve locomotion. Several technical challenges are faced by surgeons during SCS lead implantation, particularly in the confined dorsal epidural spaces in patients with spinal degenerative disease, scarring and while targeting challenging structures such as the dorsal root ganglion. Magnetic navigation systems (MNS) represent a novel technology that uses externally placed magnets to precisely steer tethered and untethered devices. This innovation offers several benefits for SCS electrode placement, including enhanced navigation control during tip placement, and the ability to position and reposition the lead in an outpatient setting. Here, we describe the challenges of SCS implant surgery and how MNS can be used to overcome these hurdles. In addition to tethered electrode steering, we discuss the navigation of untethered micro- and nanorobots for wireless and remote neuromodulation. The use of these small-scale devices can potentially change the current standard of practice by omitting the need for electrode and pulse generator implantation or replacement. Open questions include whether small-scale robots can generate an electrical field sufficient to activate neuronal tissue, as well as testing precise navigation, placement, anchoring, and biodegradation of micro- and nanorobots in the in vivo environment.

Not a String, not a Tangle, not an Aneurysm : Emerging Pattern of Large Parenchymal Bleeding in Younger Patients Associated with Abnormal Vessels on Imaging.

PURPOSE: Intracerebral hemorrhage (ICH) accounts for up to 20% of all strokes, and there is a high rate of associated morbidity and mortality. Computed tomography (CT) findings, such as a spot sign have been shown to be an independent predictor of poor outcome. We have recently encountered a succession of ICH patients who presented with a peculiar imaging finding, which we term the spot on a string sign. This is a rare imaging finding, and interestingly, all these patients presented to our institution over the last few weeks. METHODS: This was a single high-volume center series of patients who presented to our institution between 1 April and 21 May 2020. All patients underwent initial non-contrast CT brain and subsequent CT angiography (CTA). We also present laboratory and clinical data. Our primary measure was the presence of the spot on a string sign on the CTA. We also report the clinical course of these patients. RESULTS: In this study seven large-volume ICH patients with this imaging sign were identified, with a median age of 48 years (range 30-68 years). All had tested negative for coronavirus disease 19 (COVID-19). CONCLUSION: We have described an unusual imaging finding in a cohort of younger patients with large-volume ICH, all of whom presented in a 2-month period to a high-volume neurovascular unit. The cause of these ICH presentations and associated imaging findings are unclear, but we encourage other clinicians to be aware of and vigilant for this rare phenomenon, especially in younger patients with such a bleeding pattern.