Ilioinguinal/iliohypogastric Nerve Blocks as a Treatment for Pelvic Pain in a Gynecologic Population [4R]

INTRODUCTION: Ilioinguinal/iliohypogastric nerve blocks (IINBs) are a simple, minimally invasive option for managing pain associated with ilioinguinal/iliohypogastric neuropathy (IIN). This study assessed the safety and efficacy of IINBs in women with IIN associated pelvic pain. METHODS: A retrospective chart review of patients who received IINBs at The Ottawa Hospital between January 1st, 2012 and July 13th, 2017 by a single physician was performed. Patient demographics, history, examination findings, and block data were extracted. Chi-square and Mann-Whitney U tests explored differences in patient characteristics between women with and without effective response to IINBs. RESULTS: Amongst 106 meeting inclusion criteria, 381 IINBs were performed. Most women had a history of chronic pain (n=97,90%), endometriosis (n=69,65%), and/or lower abdominal surgery (n=95,90%). On examination, 56 women (53%) had tenderness within the IIN distribution, 59(56%) had point tenderness, 20(19%) had a positive Carnett’s sign, 21(20%) had allodynia, and/or 7(7%) had hyperalgesia. Data regarding effectiveness was available for 301/381 blocks. Of these, the majority (n=227,75%) greatly improved pain, 11%(n=33) somewhat improved pain, 10%(n=31) had no effect, and 3%(n=10) worsened pain. Sixty women (57%) had at least one block which greatly improved pain. Five women (5%) reported complications which could be directly related to blocks. No significant differences in patient characteristics were observed between women with and without effective response to IINBs. CONCLUSION: Ilioinguinal/iliohypogastric nerve blocks may provide pain relief for women with complex pelvic pain and features of central sensitization with a low rate of adverse events. Future prospective studies on IINB safety and efficacy are warranted.