Dear colleagues, thank you for giving me the opportunity to talk about my experience regarding wake mapping for rejection of low-grade glioma in a connectomal-based surgical approach. I have no conflict of interest. With over 20 years of follow-up, we can say now that we were able to increase both overall survival and quality of life in patients with low-grade glioma. To achieve this goal, we performed early surgery, namely without wait-and-see attitude anymore. We developed the concept of supratotorization, namely to take a margin around the flare abnormality on the preoperative MRI if functionally feasible. And of course, we achieved saferization according to a better understanding of the functional connectome into the operating theater at the individual level. I will not insist on the fact that low-grade glioma is not a benign tumor involving very frequently young patients enjoying an active life. Unfortunately, this tumor will become malignant and will kill the patient if left untreated. What is not so intuitive is that these patients are finally not so well. If you do an extensive neuropsychological examination before any treatment, in almost half of cases, you will see that, in fact, they have already developed some cognitive disorders, especially regarding the executive functions, but also the emotional processing. These cognitive deficits are not due to the lower location of the tumor, but due to the invasion by the tumor of the white matter tracts, which are the limitation of the neuroplastic potential. When I started 20 years ago, median survival after diagnosis was around six to seven years in low-grade glioma. Thanks to early research, we reached, with the French Glioma Consortium, a median survival around 15 years. More recently, we published with my colleague Luc Taillonier another series demonstrating that overall survival was now over 16 years, with preservation of the quality of life, in the vast majority of cases, beyond 12 years. Indeed, to preserve or even improve this quality of life, what we need is a mapping of the cortex and white matter tracts. To do it, we have definitely to be neuroscientists and to understand that localizationism does not exist. We have to move toward a connectomic account of brain processing, which is absolutely crucial in order to do the cortical and the subtractal mapping. Even if I am PhD in functional neuroimaging, and if I used it a lot in order to better understand mechanisms underlying neuroplasticity, I know very well the limitation of fMRI and DTI, lack of reliability, sensitivity, explaining why I will not use it in 2D operating theatre because it's not reliable enough at the individual level. This explains why I have the habit to do systematically a wake mapping by using cortical and subtractal electrical stimulation, whatever the location of the tumor. We are doing a real cognitive assessment à la carte, according to the definition by the patient himself or herself of the quality of life based on the job, hobby, habits, lifestyle, and so on. So in 2D operating theatre, the most important is to select the good tasks, but also to preserve not only the cortex, but why matter tracks the projection fibers and association fibers. In other words, my philosophy is to do a resection of a part of the brain invaded by chronic tumoral disease according to a better understanding of the functional connectome of each patient based on the cognitive monitoring performed throughout the resection online. So I do not use technology like DTI fMRI or intraoperative MRI in 2D operating theatre. I do not understand why the vast majority of patients are awake only in the so-called left dominant hemisphere. Indeed, we need both hemispheres in order to be human beings and to enjoy a perfect normal life. In other words, the right hemisphere is absolutely critical for complex movement, spatial cognition, social cognition, executive functions, emotion, personality, and so on. So we need absolutely to do a wake mapping also in the so-called non-dominant hemisphere. What about my results based on over 800 low-grade gliomas operated on in so-called eloquent areas, namely Broca's area, Wernicke's area, central area, insula, corpus callosum, and so on. In these areas, the mortality is zero, with less than 1% of severe permanent deficit, meaning that 99% of patients return to normal life, plus 25% of cognitive improvement, and 80% of positive impact on epilepsy, so with an improvement of the quality of life. We will publish a very soon paper showing that thanks to mechanisms of neuroplasticity occurring not only between the first and second surgery, but also a second and a third surgery, it has been possible more and more to reoperate patients with low-grade glioma, to prevent maculine transformation, to maintain perfect quality of life, and to increase the survival. You can see that in this sub-surgery, the median survival is about 18 years. In the whole series, the median survival is between 17 to 18 years, and, of course, I continue to perform a prospective collection of data. To achieve this kind of result, it's absolutely mandatory to better understand not only mechanisms of neuroplasticity, but also the limitation of plastic potential, and to help younger people we publish an atlas, in 3D, in an MNI template, demonstrating for each voxel the chance to recover or not following a damage, and especially following surgical research. As a neurosurgeon, it's very important to be a neuroscientist and to participate in the elaboration of new models of cognition, very helpful to navigate within the connectome of each patient into the operating theater. Once again, to help young neurosurgeons, we published recently the SORT atlas and the literature about the critical networks, including the cortical hubs and the white matter tracts, in 16 functional domains, which should absolutely be preserved during surgical research in order to return to normal life. We have recently developed a software allowing to use this atlas in the pre-planning for each individual case. The next step is to better understand the relationships not only within, but also between your networks, especially between both hemispheres. This is the concept of a metanetworking brain, namely that there is a perpetual succession of equilibrium states within the central nervous system. To apply this concept into the operating theater, we have to ask the patient to do two tasks simultaneously. And when we stimulate, we can allow the patient to continue to move, to speak, but not to do both. In other words, most important into the operating theater is to do a resection according to the functional connectome of each patient and to avoid to use too much technology because there is a risk of addiction. In conclusion, the main aim is to do a cognitive monitoring à la carte in order to preserve the quality of life for patients while increasing the median survival. Thank you for your attention.

wake mapping

low-grade glioma

connectomal-based surgical approach

supratotorization

neuroplasticity