Spinal Cord Stimulation for Intractable Chronic Lower Abdominal Neuropathic Pain Caused by Endometriosis

Overview

Endometriosis is a chronic, inflammatory disease where endometrium-like tissue is present outside the uterus. Nerve cells in the proximity of this tissue express cytokine receptors causing a signaling cascade. This results in active cross-talk between endometriosis and nerves, causing pelvic pain. Other symptoms associated with endometriosis are cyclical such as dysmenorrhea and dysuria, and non-cyclical such as dyspareunia. Despite adequate disease management, women can still experience endometriosis-related pain. A recent development proven to be efficient in treatment of neuropathic pain, is Spinal Cord Stimulation (SCS). It is also thought to be effective in the treatment of visceral pain. Several studies found Spinal Cord Stimulation (SCS) to be effective in the reduction of endometriosis-related pelvic pain. However, scientific evidence on the efficacy of SCS in visceral pain is limited.

Endometriosis is an estrogen-dependent gynaecologicalcondition characterized by the presence and growth of ectopic endometrial tissue. This tissue stimulates the infiltration of immune cells such as macrophages andmast cells into the peritoneal cavity. Both the immune cells and the endometriotic tissue secrete cytokines which create an inflammatory microenvironment. Nerve cells located in the proximity of endometriosis lesions express cytokine receptors which stimulate a cascade of signalling kinases within the nerve. This results in an active cross-talk between endometriosis and nerves causing endometriosis associated pain. Because of the chronic nature of endometriosis, treatment can be challenging difficult. It consists of three pillars: hormonal therapy, surgery and conventional pain management. Despite adequate disease management, women with endometriosis can still experience endometriosis-associated chronic pelvic pain. This might suggest that the pathology was either an incidental finding, or that other mechanisms continue to generate pain without the need for a peripheral input. One study proposed that central sensitization may be involved mechanistically in the development and maintenance of endometriosis-related pain. The hypothesis was that persistent nociceptive input from endometriotic tissues might result in increased responsiveness among dorsal horn neurons processing input from the affected viscera and pelvic tissues \[1\]. When standard endometriosis treatment is insufficient in the suppression of endometriosis-related pelvic pain, spinal cord stimulation (SCS), an accepted treatment option for neuropathic pain, could be a potential treatment.This hypothesis was substantiated by several (case) studies. However, they stated that studies on SCS for treatment of visceral pain is limited and made a call for action to broaden this knowledge