Perhaps even more intriguing is the notion that pelvic pain may ultimately be elucidated through the study of changes in neurologic systems rather than changes in gynecologic end organs themselves. If pain, initially triggered by alterations in end organs, becomes chronic and intractable by virtue of neurologic changes, this perspective may lead to entirely new approaches to preventing chronic pain.
Chronic pain may alter spinal cord neurophysiology
Under physiologic conditions, the nerves of the central nervous system guide the uterus and other organs through their respective functions. In some women, however, spinal cord neuronal circuitry becomes distorted, eliciting a pain response even when no trigger is present.
Less invasive nerve-stimulation method holds promise for pelvic pain
Nerve stimulation in a wide variety of forms has long been used to block nociceptive signals. Examples include sacral nerve root stimulators, spinal cord implants, and transcutaneous electrical nerve stimulation (TENS) units. Their efficacy varies across pain syndromes, and the duration of impact (even in successfully treated women) is uncertain. The invasive nature of the implanted devices adds to the risk and often relegates them to the bottom of the list of treatment options.
Another method of peripheral nerve stimulation—posterior tibial nerve stimulation—was recently approved by the Food and Drug Administration for treatment of bladder irritability, and may also improve urge incontinence and pelvic pain.3,4 It involves application of electrical stimuli to a very fine (acupuncture-like) needle placed next to the posterior tibial nerve, just posterior to the medial maleolus. The nerve is generally stimulated for 30 minutes a week for a series of 12 treatments. Other protocols are bound to emerge as this method is applied more broadly.
In the case of irritability, bladder pain is also often relieved. The treatment is now being tried in women with interstitial cystitis. Even though the nerve supplies of the various pelvic and vulvar organs do not all arise from the same spinal cord segments, communications within the cord may explain the broader impact of techniques like posterior tibial nerve stimulation.