Neuromodulation in Chronic Pelvic Pain: A Narrative Review

Abstract

Chronic primary pelvic pain syndrome (CPPPS) is a heterogeneous disease with unknown pathogenesis and a lack of distinct pathological features, which complicates diagnosis and therapy and has a significant impact on patients' daily life. Because pharmacological management is ineffective and long-term use may result in additional system damage, developing a more effective treatment is critical. Neuromodulation has advanced rapidly over the last few decades, and various types of neuromodulations have demonstrated efficacy in the treatment of CPPPS. In this article we discuss the evolution of neuromodulation technology in the treatment of chronic pelvic pain, its application to various subtypes of chronic pelvic pain, and the comparison of relevant efficacy and parameter differences, as well as assess the relative advantages and disadvantages of sacral neuromodulation, percutaneous tibial nerve stimulation , transcutaneous electrical nerve stimulation, electroacupuncture, and pudendal neuromodulation. Furthermore, it was noted that chronic pelvic pain should be evaluated in terms of pain, associated symptoms, psychological problems, and quality of life. Although neuromodulation approaches have been shown to be effective in treating chronic pelvic pain, more extensive multicenter trials are required to confirm this.

Keywords: Chronic pelvic pain; Chronic primary pelvic pain syndrome; Neuromodulation; Percutaneous tibial nerve stimulation; Sacral nerve modulation; Transcutaneous electrical nerve stimulation.

Fig. 1

Milestones in neuromodulation. Since the theory of gate control was put forward, various neuromodulation techniques have been developed and continuously improved. Neuromodulation has also expanded from its initial use in the treatment of lower urinary tract dysfunction to the treatment of chronic pelvic pain (CPP)

Fig. 2

Stimulation sites of various types of neuromodulations. a Sacral neuromodulation (SNM). Continuous stimulation of the S3 nerve roots with electrode and generator. The generator is placed in the subcutaneous tissues in the buttock region over the iliac crest. b Percutaneous tibial nerve stimulation (PTNS) and implantable devices (e.g., eCoin™, BlueWind RENOVA™, Bioness StimRouter™). For PTNS, a needle is inserted into the posterior tibial edge of the 3 fingers cephalic of the medial malleolus, between the posterior tibial edge and the soleus tendon, and a glued neutral electrode is placed on the same leg near the arch of the foot. Implantable devices are secured near the tibial nerve while the patients are under local anesthetic. c Pudendal nerve stimulation (PNM). PNM is applied similarly to SNM. The pudendal nerve originates from S2-S4 of the sacral nerve with a greater range of stimulation of the sacral nerve root. d Transcutaneous electrical nerve stimulation (TENS) and transcutaneous tibial nerve stimulation (TTNS). In TENS, the skin electrodes are attached to the painful area. In TTNS, the tibial nerve is stimulated with transcutaneous surface electrodes instead of with percutaneous needle electrodes