The following is a guest submission from Alysson Striner, PT, DPT, PRPC. Dr. Striner became a Certified Pelvic Rehabilitation Practitioner (PRPC) in May of 2018. She specializes in pelvic rehabilitation, general outpatient orthopedics, and aquatics and treats at Carondelet St Joesph’s Hospital in the Speciality Rehab Clinic located in Tucson, Arizona.
Recently, I had a patient present with Complex Regional Pain Syndrome (CRPS) on his right foot. He stated that the pain had started about 10 days after his prostatectomy when someone had fallen onto his right foot. He reported a bunionectomy on that foot 7 years prior and noted an episode of plantar facilities before his prostatectomy. CRPS is defined as “chronic neurologic condition involving the limbs characterized by severe pain along with sensory, autonomic, motor, and trophic impairments” in a 2017 article "Complex regional pain syndrome; a recent update" by Goh, En Lin. The article goes on to discuss how CRPS can set off a cascade of problems including altered cutaneous innervation, central and peripheral sensitization, altered sympathetic nervous system function, circulating catecholamines, changes in autoimmunity, and neuroplasticity.
A recent persistent pain theory to explain the relationship between pelvic floor and his foot could be overflow or ‘smudging’ in his homunculus. The homunculus is the map of our physical body in our brain where the feet are located next to the genitals. Possibly when one has pain, there can be ‘smudging’ of our mental body map from one area into another. I have heard this explained as though a chalk or charcoal drawing has been swipes their hand through the picture. A recent study by Schrabrun, SM et al “Smudging of the Motor Cortex is Related to the Severity of Low Back Pain” found that people with chronic low back pain had a loss of cortical organization which and that this loss was associated with the severity and location of LBP.
There are many ways to improve the organization of the homunculus and create neuroplasticity. One such way was suggested is with Transcutaneous electrical nerve stimulation (TENS) to the bottom of the foot to affect bladder spasms and pain. In recent study, “Transcutaneous electrical stimulation of somatic afferent nerves of the foot relieved symptoms related to postoperative bladder spasms,". Zhang, C et al. 2017 found that participates that had either a bladder surgery or a prostate surgery had improvement in bladder spasm symptoms and VAS scores on day two and three. Their protocol was to use two electrodes over the bottom of the foot at 5 Hz with 0.2 millisecond pulse width until a muscle twitch was achieved and was increased, but still comfortable for an hour (there is a picture of electrode placement in the article). The authors note that this neuromodulation of the foot sensory nerves may inhibit interactions between the somatic peripheral neuropathway and autonomic micturition reflex to calm the bladder and pain.
No matter what we do to help calm nervous systems from the top down; pain neuroscience education, mindful based relaxation, graded motor imagery, or from the bottom up; de-sensitization, biofeedback, or good old-fashioned TENS. The result is the same; a cortical organization and happier patients.
En Lin Goh†, Swathikan Chidambaram† and Daqing Ma. "Complex regional pain syndrome: a recent update". Burns & Trauma 2017 5:2.https://doi.org/10.1186/s41038-016-0066-4"
Schabrun SM, Elgueta-Cancino EL, Hodges PW. "Smudging of the Motor Cortex Is Related to the Severity of Low Back Pain." Spine (Phila Pa 1976). 2017 Aug 1;42(15):1172-1178. doi: 10.1097/BRS.0000000000000938
Chanjuan Zhang, et al. "Transcutaneous electrical stimulation of somatic afferent nerves in the foot relieved symptoms related to postoperative bladder spasms". BMC Urol. 2017; 17: 58. doi: 10.1186/s12894-017-0248-9