Additional file 1: of Effect of ketamine combined with magnesium sulfate in neuropathic pain patients (KETAPAIN): study protocol for a randomized controlled trial DelageNoémie MorelVéronique PicardPascale MarcaillouFabienne PereiraBruno PickeringGisèle 2017 SPIRIT 2013 checklist: recommended items to address in a clinical trial protocol and related documents. (DOC 121 kb)