outcomes in pediatric patients after stereotactic radiosurgery. Good afternoon. Okay, perfect. It's a good start. It's a good start. My name is Jeffrey Appelbaum. I'm one of the neurosurgery residents at Stanford. Today I want to talk to you about the results we have on our comparison of grading scales for radiosurgery for AVM in the pediatric population. We don't have any disclosures. So AVM is a rare disease, around 10 per million in the general population, with some disastrous outcome based on the fact that it bleeds, based on volume, based on location and age. There's multiple treatment modalities for AVMs, including endovascular treatment, microsurgery resection of the nidus, and radiosurgery, two big modalities of radiosurgery. One is gamma knife, which is more isocentric, and cyber knife radiosurgery, which we have at Stanford. There's multiple grading scales that have been developed over the years. Initially with Spetzer and Martin, the grading scale has been developed based on microsurgery resection of the AVM. As you can easily understand based on this illustration, the bigger the AVM, the more complex the venous drainage, and the positioning of the AVM in a functional area of the brain will impact the outcome of the microsurgery resection. But over the past 15 years, there's been an attempt to build a more radiosurgery-specific grading scale based on getting away from size and focusing more on volume, for example, which makes more sense from a radiosurgery perspective and radiosurgery planning. Going away from eloquent region of the brain and focusing more on depth would also make sense from a radiosurgery perspective. We compared these five grading scales that have been used in prognostic factors for AVM in our population. It's a retrospective study. We looked at 43 patients. Only 33 had a two-year follow-up. We looked at rate of obliteration. We looked at functional outcome, and we built a composite model of the two. This is the characteristic of our cohort. So median age was 13 years old. You can see 62 percent had prior endovascular treatment prior to the radiosurgery, single fraction in 77 percent of the time. This is to give you a distribution in terms of a special modern grading scale. So 92 percent of our population was either grade 2, 3, or 4, mostly grade 3 in terms of special modern. First to look at the rate of obliteration. So you see that the Pollock-Flickinger and the PARAS scale at a .81 AUC, which means that they've been very good at predicting obliteration. You see that the special modern scale was very bad at predicting obliteration. Looking at symptomatic radionecrosis, older scale failed to predict symptomatic adverse events in radionecrosis. If you look at excellent outcome, which is a composite outcome based on obliteration and no change in the ranking score, you see that, again, the Pollock-Flickinger and the proton radiosurgery AVM scale were the best at predicting these excellent outcome. So to conclude, we believe that having these scales who are more continuous scores, the Pollock-Flickinger and the PARAS scale are better at predicting obliteration and excellent outcome at two years in our cohort. We believe that going away from pure description of size but more focusing on volume makes more sense from a radiosurgery perspective. Looking at depth more than eloquence makes also more sense from a radiosurgery perspective. Definitely more studies are needed focusing on the pediatric population that would also include age in our opinion. Thank you.

grading scales

radiosurgery

pediatric patients

arteriovenous malformations

obliteration