In situ measurement of tissue impedance using an inductive coupling interface circuit

Electrical Stimulation of Dorsal Root Ganglion in the Context of Pain: A Systematic Review of In Vitro and In Vivo Animal Model Studies

OBJECTIVE

Dorsal root ganglion (DRG) has recently emerged as an attractive target for neuromodulation therapy since primary sensory neurons and their soma in DRGs are important sites for pathophysiologic changes that lead to neuropathic pain. Our aim was to create evidence synthesis about the effects of electrical stimulation of DRG in the context of pain from in vitro and in vivo animal models, analyze methodology and quality of studies in the field.

METHODS

For conducting systematic review we searched three data bases: MEDLINE, Embase and Web of Science. The quality of included studies was assessed with the Systematic Review Centre for Laboratory Animal Experimentation risk of bias tool for animal studies. The study was registered in the Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies data base.

RESULTS

We included six in vitro and eight in vivo animal studies. All included in vitro studies combined neurostimulation with substances or drugs and reported an improvement in pain-related parameters due to neurostimulation. Among in vivo studies, six used pulsed radiofrequency, while two used electrical field stimulation. All in vivo studies reported improvement in pain-related behavior following stimulation. Meta-analysis was not possible because of heterogeneity and missing data. The quality of included studies was suboptimal since all had an unclear risk of bias in multiple domains.

CONCLUSIONS

Limited data from in vitro and in vivo animal studies indicate that electrical stimulation of DRG has a positive therapeutic effect in the context of pain-related outcomes. Further studies with a standardized methodological approach and outcomes will provide useful information about electrical stimulation of DRG in animal models.