Does neuromodulation help patients who had MVD without any pain relief?
Neuromodulation is generally recommended for trigeminal neuropathic pain and not for trigeminal neuralgia. If the patient’s typical trigeminal neuralgia did not improve with microvascular decompression, we would usually consider either repeating the decompression or proceeding with percutaneous interventions. If the pain is non-neuralgic but rather neuropathic in nature, neuromodulation would be an appropriate thing to consider.
Are the electrodes ever implanted into the brain and if so, where?
The brain stimulation for facial pain is usually reserved for patients with anesthesia dolorosa – the electrodes are placed either over the surface of the brain (so called motor cortex stimulation) or in the depth of the brain in the area of thalamus or brainstem (so called deep brain stimulation).
Can a TENS unit applied somewhere help? Is the concept of neuromodulation similar to using a TENS unit?
The TENS is indeed one of the types of neuromodulation, and we do recommend trying it in patients who can tolerate placement electrodes onto painful regions. It tends to be much less effective than other neuromodulation approaches, but is definitely worth trying due to its low invasiveness. Keep in mind, that pain that does not respond to TENS may still be relieved by invasive neuromodulation with implanted devices.
Explain the relationship between neuromodulation and neuroplasticity
Neuromodulation in many ways relies on neuroplasticity – we are trying to modify neural activity by adding neuromodulation signals, and neural plasticity plays a major role in cooling down hyperactive parts of the nervous system that are responsible for development of pain in the first place.
Can neuromodulation be used in a patient with a pacemaker?
Yes, neuromodulation can be used in the presence of pacemakers and defibrillators. Your doctors need to be aware of these devices so the proper precautions may be made in choosing the device and its location in the body.
I am just finishing TMS therapy. It has not helped me. How can the Dr. find the correct “spot” for neuropathic pain?
It may be challenging to find the right spot for TMS. We usually recommend finding the face representation in the contralateral motor cortex or focusing stimulation at the pre-motor area (which is used for treatment of depression).
What is trigeminal ganglion stimulation?
Stimulation of the trigeminal ganglion (Gasserian ganglion) is reached through foramen ovale. This approach is known for many years but is rarely used, mostly because it is difficult to keep electrodes in that location as they tend to migrate over time. In principle, however, the trigeminal ganglion stimulation is a very effective approach to control neuropathic facial pain and may be considered if the pain involves several trigeminal branches at once.
Would it help with geniculate neuralgia?
The pain of geniculate neuralgia has not been investigated as an indication for neuromodulation, or at least I have not heard of it. The classical geniculate neuralgia may require either microvascular decompression or, more often, an open rhizotomy of nervus intermedius – this is what I normally recommend to my patients.
What is the success related to pain as a result of acoustic neuroma surgery/radiosurgery?
The mere presence of acoustic neuromas, the surgery to remove the tumor, and sometimes radiosurgery for the tumor may result in development of facial pain. Sometimes it presents as secondary trigeminal neuralgia and its treatment resembles trigeminal neuralgia management algorithm, but in some cases the patients develop trigeminal neuropathic pain or occipital neuralgia, and these conditions may be great indications for neuromodulation.