Spinal Cord Stimulation for Visceral Pain: Present Approaches and Future Strategies Royce W. Woodroffe,* Amy C. Pearson, † Amy M. Pearlman, ‡ Matthew A. Howard, III * Haring J. W. Nauta, § S. J. Nagel, ¶ Y. S. Hori , ¶ Andre G. Machado, ¶ Leonardo Almeida Frizon, k Logan Helland,* Marshall T. Holland,* George T. Gillies, kj and Saul Wilson, MD* *Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa; † Department of Anesthesia, University of Iowa Hospitals and Clinics, Iowa City, Iowa; ‡ Department of Urology, University of Iowa Hospitals and Clinics, Iowa City, Iowa; § Department of Neurosurgery, University of Louisville, Louisville, Kentucky; ¶ Center for Neurological Restoration, Cleveland Clinic, Cleveland, Ohio, USA; k Department of Neurosurgery, Hospital Marcelino Champagnat, Curitiba, PR, Brazil; kj Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia, USA Correspondence to: Saul Wilson, MD, Department of Neurosurgery, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA 52242, USA. Email: saul-wilson@uiowa.edu. Funding sources: No funding was received for the drafting of this manuscript. Conflicts of interest: Drs. Gillies, Helland, Holland, Woodroffe, Wilson, and Howard may receive patent royalties from the commercial license of the I- Patch intradural stimulator’s intellectual properties negotiated by their respective institutions. Drs. Gillies and Howard hold equity in the licensee and serve on its Board of Directors, respectively. Dr. Machado has distribution rights with Cardionomics and Enspire DBS, which are not related to this technology. He is a consultant for Abbott. The remaining authors have no conflicts of interest to declare. Abstract Introduction. The introduction of successful neuromodulation strategies for managing chronic visceral pain lag be- hind what is now treatment of choice in refractory chronic back and extremity pain for many providers in the United States and Europe. Changes in public policy and monetary support to identify nonopioid treatments for chronic pain have sparked interest in alternative options. In this review, we discuss the scope of spinal cord stimulation (SCS) for visceral pain, its limitations, and the potential role for new intradural devices of the type that we are developing in our laboratories, which may be able to overcome existing challenges. Methods. A review of the available literature relevant to this topic was performed, with particular focus on the pertinent neuroanatomy and uses of spinal cord stimulation systems in the treatment of malignant and nonmalignant gastrointestinal, genitourinary, and chronic pelvic pain. Results. To date, there have been multiple off-label reports testing SCS for refractory gastrointestinal and genitourinary conditions. Though some findings have been favorable for these organs and systems, there is insuffi- cient evidence to make this practice routine. The unique configuration and layout of the pelvic pain pathways may not be ideally treated using traditional SCS implantation techniques, and intradural stimulation may be a viable al- ternative. Conclusions. Despite the prevalence of visceral pain, the application of neuromodulation therapies, a stan- dard approach for other painful conditions, has received far too little attention, despite promising outcomes from uncontrolled trials. Detailed descriptions of visceral pain pathways may offer several clues that could be used to im- plement devices tailored to this unique anatomy. Key words: Spinal Cord Stimulation; Visceral Pain; Postsynaptic Dorsal Column; Dorsal Root Ganglion; Intradural Stimulation Introduction The search for safe and effective treatments of chronic in- tractable pain constitutes one of the great ongoing quests of medical science. The effective management of visceral pain of both non-cancer- and cancer-related origin is of particular importance and has been the focus of research within pharmacology, surgery, and neuromodulation for many years. Chronic pelvic pain (CPP) affects >25% of women worldwide and >9 million in the United States alone, half of them reporting reduced work capacity, and V C The Author(s) 2020. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com 2298 Pain Medicine, 21(10), 2020, 2298–2309 doi: 10.1093/pm/pnaa108 Advance Access Publication Date: 27 July 2020 Review Article Downloaded from https://academic.oup.com/painmedicine/article/21/10/2298/5876966 by guest on 08 April 2023