Sacral Neuromodulation — Procedure Guide, Recovery & Risks | MyMedicPlus

Sacral neuromodulation (SNM), also called sacral nerve stimulation, uses an implantable pulse generator (IPG) to deliver programmable low-amplitude electrical pulses to the S3 sacral nerve root via a tined lead electrode, modulating afferent and efferent pathways controlling bladder and bowel function.

Indicated for overactive bladder (urgency, frequency, urge incontinence), non-obstructive urinary retention, and fecal incontinence that persist despite behavioral therapy, pelvic floor physiotherapy, and at least two anticholinergic or beta-3 agonist medications.

Stage 1: a quadripolar tined lead inserted under fluoroscopy into the S3 foramen; motor and sensory responses confirm placement; external neurostimulator worn for 2 weeks. If symptoms improve by over 50%, Stage 2 implants the permanent IPG in the upper buttock or lower back under local anaesthesia.

Day surgery; patients go home the same day. Avoid sitting on hard surfaces for 1 week; avoid bending and strenuous activity for 4 weeks. Programming is adjusted at 2 and 6 weeks post-implant. Battery life is 3-5 years (non-rechargeable) or 10-15 years (rechargeable IPG).

Lead migration occurs in 10-15% and may require surgical revision. Infection at the implant site in 3-5% may necessitate device removal. Seroma, pain at IPG site, and device malfunction are reported. MRI compatibility varies; MRI-conditional devices (1.5T) are now available from most manufacturers.

70-85% of implanted patients achieve over 50% improvement in bladder urgency and incontinence episodes at 5-year follow-up. Fecal incontinence episodes are reduced by 70-90%. The SNS Study showed sustained efficacy for overactive bladder symptoms at 5 years in over 60% of implanted patients.