Neuromodulation for Management of Chronic Pelvic Pain: A Comprehensive Review

Spinal cord epidural stimulation for male sexual function in spinal cord injured rats

BACKGROUND

95% of men with spinal cord injuries exhibit difficulties with sexual function, including erectile dysfunction, anejaculation, retrograde ejaculation, poor ejaculatory force, and poor sperm quality.

AIM

The primary goal is to determine if well-established interventions, such as spinal cord epidural stimulation, are a feasible treatment for sexual dysfunction and if locomotor recovery training can be used to improve ejaculatory function in a rodent model of spinal cord injury (SCI).

METHODS

Male Wistar rats underwent thoracic laminectomies (shams), spinal cord transections, or moderate spinal cord contusion injuries. In urethane-anesthetized rodents, terminal spinal cord epidural stimulation was performed to target the mid-lumbar level spinal generator for ejaculation (SGE) in animals with transection spinal cord injuries at 3-, 14-, or 70-days post-injury and in animals with sham surgeries and spinal cord contusions at 70 days post-injury. The impact of locomotor training frequency was examined in two groups of rats with spinal cord contusion, which underwent 1-hr of assisted plantar stepping on a treadmill, training two or five times weekly for 6 weeks. Terminal experiments in all groups were followed by measures of sperm concentration and post-mortem testicular weight and morphology.

OUTCOMES

Spinal cord epidural stimulation consistently induced the expulsion phase of ejaculation, and occasionally the emission phase of ejaculation in rats with chronic SCI.

RESULTS

All animals were most responsive to spinal cord epidural stimulation combined with manual stimulation to induce ejaculation, with chronic injury resulting in the most consistent responses. Locomotor training improved response rates to spinal cord epidural stimulation, with intermittent training resulting in the most consistent induction of both the emission and expulsion phases of ejaculation. Sperm concentration was impacted by injury completeness and time-post injury, which was lowest in the chronic complete transection group of rats. Locomotor training resulted in an overall increase in sperm concentration, with 2 days per week of training resulting in a significant improvement of sperm motility.

CLINICAL IMPLICATIONS

Spinal cord epidural stimulation combined with locomotor training is a feasible intervention for individuals with SCI who seek to regain sexual function.

STRENGTHS AND LIMITATIONS

Although we have anecdotal reports of non-targeted L3 spinal cord epidural stimulation inducing ejaculation in humans having spinal cord injuries, the current outcomes may be underestimated as stimulation was carried out in anesthetized animals.

CONCLUSION

Spinal cord epidural stimulation to target the SGE is a feasible intervention for sexual dysfunction following SCI.

Dorsal root ganglion stimulation for patients with chronic pelvic pain: A retrospective review of patient experiences and long-term outcomes

Introduction

Chronic pelvic pain (CPP) is a refractory condition that has physical, emotional, and financial impacts on patients. Dorsal root ganglion stimulation (DRGS) is a promising interventional modality for patients with refractory CPP, however studies of long-term outcomes are limited. We aim to present the results from a retrospective review of 31 patients with CPP treated using DRGS.

Materials and methods

IRB approval was obtained. A retrospective chart review was conducted, including 31 patients who underwent a DRGS trial between 2017 and 2022 at two academic centers. Pain history, trial/implant lead configuration, complications/revisions, pain scores, functional goals, and medication use were recorded.

Results

Thirty-one patients with CPP underwent a 7-10 day DRGS trial between 2017 and 2022. Of the 31 patients, 21 (68%, CI 50-81%) had a successful trial, defined as >50% reported pain relief. Twenty patients underwent DRGS implantation. Average follow-up was 28.2 ± 17.3 months. Nine patients (45%) required revision surgery for lead migration or fracture. Thirteen patients remain implanted with an average reported percent relief of 55 ± 15%. Seven patients were explanted (35%), with an average time to explant of 12.5 ± 3 months.

Conclusions

This study presents one of the largest groups of patients with DRGS for the treatment of CPP. The results highlight the variable experiences of patients after DRGS trial/implant. We report on the incidence of lead migration and fracture, sparingly described in the literature. Larger, prospective studies are needed to elucidate which patients with CPP may benefit most from DRGS, and to better understand the incidence and implications of complications.

Spinal Cord Stimulation for Intractable Visceral Pain Originating from the Pelvic and Abdominal Region: A Narrative Review on a Possible New Indication for Patients with Therapy-Resistant Pain

Aim

Visceral pain, characterized by pain that is diffuse and challenging to localize, occurs frequently and is difficult to treat. In cases where the pain becomes intractable despite optimal medical management, it can affect patients' Quality of Life (QoL). Spinal Cord Stimulation (SCS) has emerged as a potential solution for intractable visceral pain.

Purpose

In this narrative review, we collected all evidence regarding the efficacy of SCS for visceral pain across various underlying conditions.

Methods

A comprehensive literature search was conducted in PubMed, Embase, and Web of Science in which articles published from October 1st, 1963 up to March 7th, 2023 were identified.

Results

Seventy articles were included in this review of which most were retrospective cohort studies, case series and case reports. The studies, often with a small number of participants, reported on SCS for chronic pancreatitis, anorectal pain and bowel disorders, gynaecological diagnoses, visceral pelvic pain, urological disorders and finally general visceral pain. They found positive effects on pain and/or symptom relief, opioid consumption, anxiety and depression and QoL. Complications occurred frequently but were often minor and reversible.

Conclusion

Better screening and selection criteria need to be established to optimally evaluate eligible patients who might benefit from SCS. A positive outcome of a sympathetic nerve block appears to be a potential indicator of SCS effectiveness. Additionally, women receiving SCS for endometriosis had a better outcome compared to other indications. Finally, SCS could also relief functional symptoms such as voiding problems and gastroparesis. Complications could often be resolved with revision surgery. Since SCS is expensive and not always covered by standard health insurance, the incorporation of cost-analyses is recommended. In order to establish a comprehensive treatment plan, including selection criteria for SCS, rigorous prospective, possibly randomized and controlled studies that are diagnosis-oriented, with substantial follow-up and adequate sample sizes, are needed.

Dorsal Root Ganglion Stimulation for the Management of Phantom Bladder Pain: A Case Report

Phantom bladder pain, a rare condition following cystectomy, can pose a challenge to pain management providers. We present the case of a 43-year-old male who developed severe phantom bladder pain post-cystectomy. Despite multiple treatments, his symptoms persisted, significantly affecting his quality of life. Dorsal root ganglion stimulation (DRGS) was attempted after conventional therapies failed. The DRGS trial provided significant relief, leading to permanent implantation and a 90% reduction in pain. This case highlights DRGS as a potential treatment for phantom bladder pain, expanding its applications beyond traditional uses. Further research is needed to elucidate its mechanisms and broader applicability.