Selective Nerve Root Stimulation: Facilitating the Cephalocaudal “Retrograde” Method of Electrode Insertion

Abstract

Selective nerve root stimulation (SNRS) as a method was first presented in 1998 and was published in 1999. Despite advances at that time in dual electrode technology and patient controlled programming, “anterograde” spinal cord stimulators (SCSs) were unable to consistently produce and maintain paresthesia in the neck, pelvic, and foot dermatomes. As well some individual lower extremity dermatomes lacked SCS paresthesia coverage. Thus, selective, cephalocaudal, “retrograde” electrode placement was developed to improve capture in these targets. Safety concerns limited cervical in vivo application; however, lumbosacral placement gained interest in the evaluation of many difficult-to-treat conditions. Despite initial enthusiasm and success, many encountered technical difficulty entering the lumbar intralaminar space from the superior to inferior or cephalocaudal, “retrograde” direction. Subsequently this author began teaching a needle entry technique utilizing a lateral intralaminar approach (Figs. 18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, and 18.10). This mimics the “single-shot epidural” needle placement applied commonly by interventional practitioners. This facilitates entry of the stimulation electrode into the epidural midline, and standardizes entry of the needle below the conus at L2–3.