Percutaneous Test Lead Placement at the Sacral Foramen
A temporary lead is inserted near S3 to test patient response.
- S3: Target nerve root (sacral foramen)
- 3–14 days: Trial duration (outpatient test)
- ≥50%: Response threshold (symptom improvement)
- Local: Anesthesia (awake sensory testing)
Placement procedure
Placeholder: needle guided fluoroscopically into the S3 foramen.
Delivering Controlled Electrical Pulses to the Sacral Nerve
The lead delivers tunable low-amplitude electrical pulses.
- 210 µs: Pulse width (typical setting)
- 14 Hz: Frequency (standard programming)
- 0–10 V: Amplitude range (patient titrated)
- Mild tingle: Sensation goal (perineal/vaginal area)
Stimulation parameters
Placeholder: amplitude titrated until comfortable motor/sensory response.
Modulating the Bladder-Spinal Cord Voiding Reflex Arc
Stimulation normalizes abnormal afferent bladder signaling.
- Sacral: Reflex arc (S2–S4 micturition center)
- Dampened: Afferent effect (urgency signaling)
- Neuromodulation: Mechanism (not ablation)
- Days–weeks: Onset (gradual improvement)
Reflex normalization
Placeholder: pulses recalibrate bladder-brain signal traffic.
Permanent Implantable Pulse Generator Placement
A battery-powered generator is implanted after trial success.
- ~5–15 yrs: Device life (battery dependent)
- Upper buttock: Implant site (subcutaneous pocket)
- ≥50% trial gain: Eligibility (response criterion)
- Outpatient: Procedure (minor surgery)
Permanent placement
Placeholder: generator connected to the successful trial lead.
Sustained Symptom Control With Chronic Neuromodulation
Long-term stimulation maintains reduced urgency and leakage.
- ~70–80%: Success durability (at 5-year follow-up)
- Major: Symptom reduction (urgency/frequency)
- As needed: Reprogramming (noninvasive adjustment)
- Fully: Reversibility (device removable)
Chronic outcomes
Placeholder: durable symptom control sustained over years.
Placeholder: most successful trials keep long-term benefit.