Neurogenic (or neuropathic) pain is due to any damage of the nerves or pain centres in the spinal cord or in the brain: phantom limb pain (after amputation), nerve compressions or sections, polyneuropathies, plexus avulsions, paraplegic pain, pain after brain infarct (thalamic syndrome), trigeminal neuralgia, postherpetic pain (after zona infection), pain after lumbar disc operations, etc.
The reduction of inputs from the body causes an overactivity of the pain thalamus and related cortical areas, leading to the appearance of pain. Our approach centers on a therapeutic lesion of a thalamic area which has lost its normal function. Its overactivity causes and maintains the pain. This allows the coupling of efficiency and sparing of brain functions, and thus if necessary a pain relief on both sides.
Where to go to provide an efficient and sparing pain relief relates to years of work, in our case more than 20 years, of study of the mechanism of neurogenic pain and its most adequate control thanks to consequent selection of brain targets. The good news is: we can provide pain relief without reducing motor, sensory and cognitive functions, and without risk to increase pain mechanisms. We can apply this treatment on both sides of the brain if necessary. The long term efficiency of the treatment stands at 60-70% mean pain relief. There is a low risk profile, mainly comprising a bleeding risk in the target, which can be estimated at less than 1%. The risk of collateral damage to structures around the target is significantly reduced by the real-time monitoring of the thermal work, the absence of mechanical brain shift and the above-mentioned targeting accuracy. Long term negative effects of the ultrasound lesioning process can be excluded thanks to the fact that it is a thermocoagulation, the long term innocuity of which has been demonstrated by more than 60 years of functional neurosurgical activity using radiofrequency thermocoagulation. Long term results of the focused ultrasound treatments are not yet available. However, as the targets we use are exactly the same as the ones we have developed and used over more than 20 years using the electrode penetration technique with radiofrequency , the same long term results can be expected for all our ultrasound treatments, a fact already confirmed by our one-year results with focused ultrasound.
EEG power spectra of a neurogenic pain patient. The green curve shows normal brain activity, the red curve the patient’s brain activity before treatment, the dark blue curve his brain activity 3 months after treatment and the light blue curve 1 year after. The green and the light blue curves are no longer to be distinguished from one another statistically. The normalization of low (delta and theta) frequencies was due to the Central Lateral Thalamotomy, the normalization of the high (beta and gamma) frequencies to the activation of self-healing psycho-emotional ressources.
Three Video Interviews of Prof. Dr Med. D. Jeanmonod
Prof. Jeanmonod is talking about brain surgery with ExAblate Neuro and patient stories.
Recordings performed by InSightec Ltd during the 3rd International Symposium on Focused Ultrasound in October 2012 in Washington.
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