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Background: Navigated transcranial magnetic stimulation (nTMS) is a well-established preoperative mapping tool for motor-eloquent glioma surgery. Machine learning (ML) and nTMS may improve clinical outcome prediction and histological correlation., Methods: This was a retrospective cohort study of patients who underwent surgery for motor-eloquent gliomas between 2018 and 2022. Ten healthy subjects were included. Preoperative nTMS-derived variables were collected: resting motor threshold (RMT), interhemispheric RMT ratio (iRMTr)-abnormal if above 10%-and cortical excitability score-number of abnormal iRMTrs. World Health Organization (WHO) grade and molecular profile were collected to characterize each tumor. ML models were fitted to the data after statistical feature selection to predict tumor grade., Results: A total of 177 patients were recruited: WHO grade 2-32 patients, WHO grade 3-65 patients, and WHO grade 4-80 patients. For the upper limb, abnormal iRMTr were identified in 22.7% of WHO grade 2, 62.5% of WHO grade 3, and 75.4% of WHO grade 4 patients. For the lower limb, iRMTr was abnormal in 23.1% of WHO grade 2, 67.6% of WHO grade 3%, and 63.6% of WHO grade 4 patients. Cortical excitability score ( P = .04) was statistically significantly related with WHO grading. Using these variables as predictors, the ML model had an accuracy of 0.57 to predict WHO grade 4 lesions. In subgroup analysis of high-grade gliomas vs low-grade gliomas, the accuracy for high-grade gliomas prediction increased to 0.83. The inclusion of molecular data into the model-IDH mutation and 1p19q codeletion status-increases the accuracy of the model in predicting tumor grading (0.95 and 0.74, respectively)., Conclusion: ML algorithms based on nTMS-derived interhemispheric excitability assessment provide accurate predictions of HGGs affecting the motor pathway. Their accuracy is further increased when molecular data are fitted onto the model paving the way for a joint preoperative approach with radiogenomics., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Background: Diffuse gliomas have an increased biological aggressiveness across the World Health Organization (WHO) grading system. The implications of glioma grading on the primary motor cortex (M1)-corticospinal tract (CST) excitability is unknown., Objective: To assess the excitability of the motor pathway with navigated transcranial magnetic stimulation (nTMS)., Methods: Retrospective cohort study of patients admitted for surgery with diffuse gliomas within motor eloquent areas. Demographic, clinical, and nTMS-related variables were collected. The Cortical Excitability Score (CES 0 to 2 according to the number of abnormal interhemispheric resting motor threshold (RMT) ratios) was calculated for patients where bilateral upper and lower limb mapping was performed., Results: A total of 45 patients were included: 9 patients had a low-grade glioma and 36 patients had a high-grade glioma. The unadjusted analysis revealed an increase in the latency of the motor evoked potential of the lower limb with an increase of the WHO grade (P = .038). The adjusted analysis confirmed this finding (P = .013) and showed a relation between the increase in the WHO and a decreased RMT (P = .037) of the motor evoked responses in the lower limb. When CES was calculated, an increase in the score was related with an increase in the WHO grade (unadjusted analysis-P = .0001; adjusted analysis-P = .001) and in isocitrate dehydrogenase (IDH) wild-type tumors (unadjusted analysis-P = .020)., Conclusion: An increase in the WHO grading system and IDH wild-type tumors are associated with an abnormal excitability of the motor eloquent areas in patients with diffuse gliomas., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Giuseppe Campani (1635-1715) was a polymath in Rome, Italy, during the Scientific Revolution in the XVIIth century. In particular, he forged the screw barrel microscope and was manufacturing his own lenses for microscopes and telescopes. He mastered the art of lens grinding. Those lenses have been analyzed with modern methods and turned out to be of extremely good quality, shining light on the fact that Giuseppe Campani mastered the theories of optics. Moreover, in a letter that Giuseppe Campani sent to Pope Innocent XI, he clearly described the use of a microscope for the examination of wounds of legs. This letter dates back to 15 August 1686 and is the first evidence of the use of microscopes to analyze wounds, sores, and anatomic specimens in medical and surgical settings. MG Yasargil previously showed the lithography accompanying this letter and was the first to recognize its great importance. We accessed this original letter in the Vatican Library, and for the first time we have translated it from Latin to English in order to unveil its significance in the context of the Scientific Revolution and the history of medicine and surgery., (Copyright © 2017 by the Congress of Neurological Surgeons.)

Background: Supratentorial hemangioblastomas are rare lesions, occurring either sporadically or in von Hippel-Lindau disease., Objective: Following recent advances in our understanding of the natural history of von Hippel-Lindau-associated cerebellar and spinal hemangioblastomas, we conducted a study of the natural history of supratentorial hemangioblastomas in von Hippel-Lindau disease., Methods: We reviewed a series of 18 supratentorial hemangioblastomas in 13 patients with von Hippel-Lindau disease. Clinical, genetic, and serial imaging data and operative records were analyzed., Results: Hemangioblastomas were most commonly seen in the temporal lobe. Only 6 tumors had a cyst at diagnosis or during follow-up, and only 6 patients had associated symptoms at presentation or during follow-up. The most frequent clinical presentations were intracranial hypertension and visual loss. Of 14 tumors with documented serial imaging, 13 demonstrated tumor growth. Rates and patterns of tumor growth were unique to each patient. The mechanism of cyst formation described in other locations was also demonstrated in the supratentorial region. Patterns of peritumoral edema and rate of cyst formation seemed to be influenced by the presence of anatomic barriers. Germline VHL mutation was identified in all patients, but no specific genotype-phenotype correlation was found, although a familial predisposition is suggested., Conclusion: This series illustrates the wide variation in tumor locations, patterns of growth, and edema progression seen in supratentorial hemangioblastomas and adds to our knowledge of the natural history of hemangioblastomas.

Objective: Neurofibromatosis Type 1 (NF1) is known to be associated with vascular lesions. Association with an extracranial vertebral artery aneurysm is very rare. We report the case of such an aneurysm mimicking a cervical neurofibroma in NF1., Clinical Presentation: An 18-year-old woman with previously diagnosed NF1 presented with a C6 radiculopathy. There were no clinical features suggesting a vascular origin for the lesion. The computed tomographic and standard magnetic resonance imaging scans showed a C5-C6 contrast-enhancing lesion responsible for bony erosion. Subsequent, magnetic resonance angiography and digital subtraction angiography diagnosed the lesion as a C5-C6 vertebral artery aneurysm., Intervention: The lesion was treated by endovascular occlusion of both the aneurysm and the parent vertebral artery with an initial immediate disappearance of the pain., Conclusion: This case serves as a reminder of the importance of ruling out a vertebral artery aneurysm with angiography when managing cervical lesions in patients with NF1.