Sacral neuromodulation involves electrically stimulating sacral nerve roots to modulate bladder function and treat urinary incontinence and retention. It works by activating afferent nerves in the sacral nerve roots that connect to spinal cord pathways controlling micturition. There are two stages - an initial temporary test using an external pulse generator followed by implantation of a permanent internal pulse generator if the test is successful. Potential indications include overactive bladder, urinary retention, and pelvic pain. The document discusses various neuromodulation techniques and mechanisms of action in treating different lower urinary tract dysfunctions.

2. By

3. Normal bladder during storage and voiding phase

4. Definition
- Electrical stimulation of somatic afferents to modulate sensory processing &
micturition reflex pathways in spinal cord.
Types: ( of sacral neuromodulation )
1) Sacral rhizotomy.
2) Electric stimulation of nerve roots:
A. Sacral posterior root neuromodulation.
B. Sacral anterior root neuromodulation (Brindley device)
3) Bladder rehabilitation by electrical stimulation:
a) Posterior (percutaneous) tibial nerve stimulation
b) external temporary electrical stimulation (e.g.penile/clitoral or intracavital).
c) Chronic peripheral pudendal stimulation
d) Transurethral Electrical Bladder Stimulation (TEBS)

5. Role of sacral neuromodulation in urology:
Neurogenic LUT dysfunction:
Storage and voiding dysfunction
I.C & pelvic pain:
• SNM significant improvement in bladder pain & voiding dysfunction
• Recommended if medical ttt failed & before surgical intervention
Chronic genitourinary pain
• Chronic nonbacterial prostatitis
• Ch. Epididymo-orchalgia
• vovodynia

6. Sexual function
• No study were constructed yet on pure sexual dysfunction cases
• observation of sexual function improvement occurred during follow up of
SNS on voiding dysfunction
o In male improve erection
o In female improve desire, arousal & lubrication
Children
• Nocturnal enuresis
• Urinary incontinence
• Urinary retention

7. Mechanism of action:
Stimulation of somatic afferent nerves in post root of sacral nerve (S3):
Regardless whether LUT dysfunction involve storage or emptying
abnormalities, afferent nerve serve as common crossroads in neurogenic
wiring of system so aff nerves can:
• Turn on voiding reflex by – of gaurding rfx
• Turn off supraspinally mediated hyperactive voiding by blocking
ascending sensory pathway.

8. Mechanism of Action of Sacral Neuromodulation in
Overactive Bladder:

9. Mechanism of Action of Sacral Neuromodulation in
Urinary Retention

10. Method of appliance:
Stage 1 ( Electrode application and PNE):
Under fluoroscopic control a percutaneously temporary test electrode was
placed near the nerve, in the sacral foramen alongside a sacral nerve,
usually S3 and then percutaneous nerve evaluation (PNE) and test
stimulation, provided by an external pulse generator, was performed.
Generally, the PNE lasted for 5-7 days, an electrode is placed.

11. Stage 2 ( permanent device application):
• Once the patient is respond, the patient proceeds to the second stage of
implantation, in which the electrode is connected by cables under the skin
to an implanted, programmable, pulse generator.
• The generator provides stimulation within established stimulation
parameters.

12. Contraindications to sacral neurostimulation
o Tumour of SC
o Myogenic damage (acontractility)
o Peripheral nerve injury
o End-stage, small contracted bladder
o Pregnancy
o Sacral SCI
o Incapacitated patient (eg MR)
o Functional urinary incontinence
o Non-complianc

13. Complication
- pain at generator site
- pain at implant site
- lead migration
- revision
- infection
- skin irritation
- adverse changes in bowel/bladder function

14. Idea
• The target area is S2-4 which lead to a strong contraction of the urethral
sphincter and/or pelvic floor, which reflexly inhibit the micturition and DO ,
• it is effective in selected cases (patients that do not suffer from a complete
spinal cord lesion).
Indication as before plus
o SUI as pelvic muscle exercise

15. Methods
a) Posterior (percutaneous) tibial nerve stimulation
the posterior tibial nerve (PTNS) delivers electrical stimuli to the
sacral micturition centre via the S2-S4 sacral nerve plexus.
the PTNS is stimulated with a fine, 34-G, needle, which is inserted
just above the medial aspect of the ankle . Transcutaneous stimulation
is also available.
Treatment cycles typically consist of 12-weekly treatments of 30 minute.

16. b) external temporary electrical stimulation (e.g.penile/clitoral or
intracavital).
C) Intravesical electrostimulationIt:
• Can improve bladder capacity, bladder compliance , the sensation of bladder
filling and hypocontractility,
• Daily stimulation sessions of 90 minutes at a frequency of 20 Hz are used for
at least 1 week.
• It is indicated in peripheral lesions “the best candidates” that the detrusor
muscle must be intact, and that at least some afferent connection between
the detrusor and the brain must still be present.

17. • Pre requisites for such use are :
o Intact neural pathways between the sacral cord nuclei of the pelvic
nerve and thebladder
o Bladder that is capable of contracting
• The chief applications are:
• in patients with inefficient or non reflex micturition after spinal cord
injury
The Brindly device
is the one most commonly used.

18. • Brindly device:
o Electrodes are applied intradurally to s2,s3 and s4 nerve root but the
pairs can be activated independently:
o The detrusor is usually innervated primarily by S3 and to smaller extent
by S2 or S4
o Rectal stimulation is by means of all three roots equally
o Electrical stimulation is chiefly by S2 with small contribution of S3 and
non from S4
o Electrical stimulation of the ventral sacral roots with some techniques
to :
 Reduce detrusor hyperactivity
 Obviate striated sphincter dyssynergia