What is Neuro-stimulation?
Simulation of nerves electrically with implanted leads close to the involved segment or nerve with/ without implanted power generator to inhibit or block the sensation of pain is called Neuro-stimulation.
What is Spinal Cord Stimulation?
When the lead is implanted in the epidural space to stimulate spinal cord itself is called Spinal Cord Stimulation.
What is TENS?
TENS is Trans-cutaneous Electrical Nerve Stimulation. Here nerve or spinal segment is stimulated with superficial current applied over the skin of same dermatome.
What is the difference between TENS and SCS?
In Spinal Cord Stimulation, implanted electrodes stimulate it. In TENS electrodes applied over skin. Former is better as several other mechanisms acts to relieve pain.
What is the mechanism of action of Spinal Cord Stimulation?
It acts by several mechanisms:
1. Gate control theory- stimulation of larger diameter nerve fibers inhibits pain carrying small diameter fibers.
2. Secretion of putative neurotransmitters that inhibits pain signals.
3. It produces supraspinal inhibition of pain either by inhibiting pain transmission or modulation of pain impulses.
4. Sympathetic inhibition by some mechanisms.
Who are the candidates for Neuro-stimulation?
Neuropathic pain responds best with spinal cord stimulation. When most of the other options of has failed neuro-stimulation should be tried.
1. Failed back surgery syndrome (FBSS) / Post laminectomy syndrome / Failed back syndrome
2. Radiculopathy involving single or multiple roots,
3. Complex Regional Pain Syndrome
4. Diabetic Neuropathy
5. Atypical recurrent angina
6. Post-scar or post-traumatic neuralgia,
7. Post-herpetic neuralgia
8. Phantom limb pain
What is the success rate for these procedures?
Overall success rate (more than 50% pain relief) is around 80%. Before implanting the Power generator it is advisable to give a trial stimulation to assess the efficacy of this procedure. Failure after successful trial is possible but very rare.
What is trial stimulation?
It is like temporary pacemaker. The stimulating electrodes / leads are implanted and stimulated with external power source. Then the patient is asked to assess pain relief over next few days. If pain relief is more than 50% then permanent implantation is done.
What is the cost of trial stimulation?
It depends on the type of leads used. It may vary roughly between 0.5-1 lakh of Indian Rupees.
What is the cost of permanent SCS?
It again depends on type of leads, and type of IPG. It may vary from 4 to 7 lakhs of Indian Rupees.
What are the preliminary steps before SCS?
1. Evaluation of pain.
2. Psychiatric evaluation.
3. Patient education: about pre- and post-procedure plan and long-term management, cost effectiveness.
4. Planning of procedure.
Is it cost-effective?
If we weigh between sufferings, total cost of other form of treatment SCS is cheaper if patient can afford.
How long it is effective?
1. It depends on type of IPG.
2. It depends on type of stimulation parameter.
3. With conventional type it is effective for 5-8 years. IPG should be replaced after that.
Can the patient lead a normal life?
1. In most patients SCS can be kept in “OFF” mode for sometimes without return of pain. Otherwise patients can lead near normal life style.
2. There are some situation when it is kept in “OFF” mode by a remote or magnet by the patients themselves.
3. Normal household equipment, such as cell or portable phones, computers, TVs, microwaves, and other appliances are safe to use with the stimulator.
What are the conditions when SCS are kept in “OFF” mode?
1. Driving cars or using heavy equipment.
2. Passing through metal detectors.
3. Passing through anti-theft devices.
4. When flying, during take off and landing.