Spinal motor mapping by epidural stimulation of lumbosacral posterior roots in humans.

Ursula S Hofstoetter,Aymeric Bayart,Brigitta Freundl,Peter Lackner,Karen Minassian,Heinrich Binder,Ivan Perret

doi:10.1016/j.isci.2020.101930

Ursula S Hofstoetter, Aymeric Bayart + Show 5 more

Open Access

https://doi.org/10.1016/j.isci.2020.101930

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Abstract

SummaryEpidural electrical stimulation of the spinal cord is an emergent strategy for the neurological recovery of lower-extremity motor function. Motoneuron pools are thought to be recruited by stimulation of posterior roots. Here, we linked electromyographic data of epidurally evoked lower-extremity responses of 34 individuals with upper motoneuron disorders to a population model of the spinal cord constructed using anatomical parameters of thousands of individuals. We identified a relationship between segmental stimulation sites and activated spinal cord segments, which made spinal motor mapping from epidural space possible despite the complex anatomical interface imposed by the posterior roots. Our statistical approach provided evidence for low-threshold sites of posterior roots and effects of monopolar and bipolar stimulation previously predicted by computer modeling and allowed us to test the impact of different upper motoneuron disorders on the evoked responses. Finally, we revealed a statistical association between intraoperative and postoperative mapping of the spinal cord.

Highlights

Epidural electrical stimulation (EES) of the spinal cord is broadly known as a treatment for chronic intractable pain of the trunk and limbs (Krames et al, 2009; Rock et al, 2019; Shealy et al, 1967)
We identified a relationship between segmental stimulation sites and activated spinal cord segments, which made spinal motor mapping from epidural space possible despite the complex anatomical interface imposed by the posterior roots
Our statistical approach provided evidence for low-threshold sites of posterior roots and effects of monopolar and bipolar stimulation previously predicted by computer modeling and allowed us to test the impact of different upper motoneuron disorders on the evoked responses

Summary

Introduction

Epidural electrical stimulation (EES) of the spinal cord is broadly known as a treatment for chronic intractable pain of the trunk and limbs (Krames et al, 2009; Rock et al, 2019; Shealy et al, 1967). Following the observation that EES can enable volitionally initiated activation of otherwise paralyzed muscles (Angeli et al, 2014; Harkema et al, 2011), the facilitation of overground walking was the breakthrough finding (Angeli et al, 2018; Gill et al, 2018; Wagner et al, 2018). These first advances in demonstrating efficacy have partially preceded the understanding of the underlying principles.

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