Stoller's Afferent Nerve Stimulation (SANS)

Functional disorders of the pelvic floor, colorectal, or uro-gynecological systems, according to international guidelines (CSI), should primarily be approached with Pelvic Floor Rehabilitation using conventional techniques: Biofeedback Therapy (BFB), Pelvic-Perineal Kinesiotherapy (CPP), and Functional Electrical Stimulation (FES). Among minimally invasive techniques, SANS is the most commonly applied.

SANS is particularly indicated for non-neurogenic overactive bladder, non-obstructive urinary retention, chronic pelvic pain, dyspareunia, interstitial cystitis, neurogenic dysfunctions of the lower urinary tract, and in colorectal applications for obstructed defecation syndrome and fecal incontinence with preserved neuro-anatomical integrity.

This electrostimulation procedure is contraindicated in the following cases:

• Pacemaker carriers
• Patients with heart conditions
• Epileptic patients
• Pregnant women
• Patients with active phlebitis or thrombophlebitis
• Oncology patients
• Skin lesions in the treatment area.

This technique is well tolerated by patients, as it uses electrical stimulation at the ankle level of the tibial nerve, which is a mixed sensory and motor nerve. Its fibers originate from sacral roots, also innervating the bladder and perineal area.

By stimulating these fibers in a retrograde manner, "neuromodulation" of the bladder and perineal area is achieved. This process inhibits the bladder's detrusor muscle (responsible for the urge to urinate and bladder emptying) and regulates the neurological circuit responsible for transmitting pain signals to the cerebral cortex.

The stimulation current ranges from 1 to 10 milliamperes with a fixed frequency of 20 Hz and a pulse width of 200 milliseconds. The current is increased until a flexion of the big toe or a fanning out of all the toes is observed.

In most cases, the motor response is accompanied by a sensory response of tingling that extends to the sole of the foot.

The electric stimulation is set to a threshold level tolerated by the patient. During the session, the intensity of the electric stimulus may be increased whenever the sensation reduces due to adaptation.