The urinary bladder has two functions: The first is to store urine coming from the kidneys in a comfortable manner. The second function is to void urine voluntarily and completely. A very important anatomical structure is the external urinary sphincter that needs a coordination with the muscles of the bladder in order to have a completely functional unit. This coordination and voluntary control of urine is due to a network of central nervous system. When this coordination becomes imbalanced, certain signs and symptoms show up that need to be treated. Sacral neuromodulation is used in France and United States for this type of urologic indications since few years. This latest treatment is used for refractory, chronic conditions in patients with overactive bladder and patients with urinary retention (non-obstructive). It is recently used in non-urologic cases as fecal incontinence and constipation. It is considered the last resort for urgency/ urge incontinence after failure/intolerance of medical treatment and/or injection of botulinum toxin A in the bladder. Besides, it is used for urinary retention (majorly in women) with or without sphincteric anomalies. This technique showed great results in young females with unexplained urinary retention with non-relaxation of the sphincter.
This procedure is done when the urologist inserts an electrode in the S3 sacral foramen (from the lower back) and connects the electrode to an external stimulator. This electrode transmits signals (current) to S3 which in turn modifies the signals transmitted by this nervous network (reset of the system) for better control of the bladder and sphincter. This technique is very conservative in the meaning that nothing is destroyed or removed, and it is reversible as the effects stop when the stimulator is stopped. A testing phase is usually done for 2-3 weeks and if the patient reports >50% improvement in symptoms; a definitive battery (stimulator) is placed in the lower back with a very small incision. The testing phase takes about 60 minutes (operating time) and the definitive phase of the procedure about 30 minutes.