1. 2024;27;E899-E907Novel Injectable Nerve Stimulation Electrode Placed on the Dorsal Root Ganglion Using an Extravertebral Approach: A Feasibility Study in Cadavers
   Feasibility Study
   Bart Billet, MD, Christian Jessen, MD, Bernhard Moriggl, MD, PhD, Derrick Liu, MS, Emily Szabo, MS, Stephan Nieuwoudt, PhD, Alaa Abd-Elsayed, MD, Amol Soin, MD, and Thomas Fichtner Bendtsen, MD, PhD.

BACKGROUND: Dorsal root ganglion stimulation (DRGS) is an established method for treating persistent and severe pain conditions. However, performing DRGS has significant challenges. Current DRGS systems are expensive, hindering accessibility for many patients and health care systems. Additionally, placing DRGS devices requires specialized training in epidural techniques and lead anchoring methods. Technical and financial requirements also limit the clinical applicability and availability of DRGS.

OBJECTIVES: This study evaluated the feasibility of a new method for rapidly delivering near- DRG stimulation in human cadavers. The method involves a fluoroscopy-guided transforaminal approach using a fully implantable, injectable electrode, and its associated delivery system.

STUDY DESIGN: A human cadaver feasibility study.

SETTING: A cadaver laboratory.

METHODS: In this study, 3 anesthesiologist pain physicians received training on the injectable electrode device and delivery system using spine phantom models. They then applied the device’s associated implantation techniques to 2 adult male cadavers. In the first cadaver, a single injectable electrode was placed near the left L2 lumbar DRG. In the second cadaver, injectable electrodes were placed near the left L1 and L2 DRG levels, and a benchmark DRGS device was installed at the left L1 level using fluoroscopic guidance. A careful anatomical dissection was then performed for each implanted device.

RESULTS: The stimulating contacts of the injectable electrodes were accurately positioned within one mm of the DRG at the lumbar L1 and L2 levels in both cadavers. The distances of both the injectable lead and benchmark DRGS device at the L1 level were measured as one mm from the posterior aspect of the DRG.

LIMITATIONS: The findings of this study are based on anatomical examinations of a limited number of human cadavers and may not fully represent living human anatomy.

CONCLUSIONS: To our knowledge, this feasibility cadaver study is the first of its kind to examine the accuracy and efficiency of a fluoroscopy-guided transforaminal approach to place injectable electrodes near the DRG. These promising results suggest that this method could be a viable alternative to existing DRGS techniques, warranting further investigation into its clinical potential.

KEY WORDS: Cadaveric study, technical report, anatomical feasibility, dorsal root ganglion stimulation, peripheral nerve stimulation, chronic pain, neuropathic pain, injectable electrode