Osvaldo Vilela-Filho

Background Psychiatric disorders are increasingly contributing to global disability. Despite advances in conservative management, the prevalence of treatment-resistant cases remains high. Meanwhile, neurosurgery for psychiatric disorders (NPD) remains underused, largely due to strict regulations and historical concerns, particularly those related to neuropsychological side effects (NPSE). Objective To address this issue, we conducted a systematic review with meta-analysis to compare NPSE associated with radiofrequency ablative NPD to those observed in neuro-oncological, neurovascular and epilepsy surgeries. Methods PubMed, Embase and LILACS databases were searched in April 2024 for articles published in English/Spanish from 1990 to 2022, following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Results A total of 48 articles with 2678 participants were included. The frequency of transient and permanent NPSE in the NPD group ranged from 0.94% to 11.50% and 0.94% to 2.03%, respectively, comparable to the other surgical groups (epilepsy: 0.31–11.70%; vascular: 0.52–22.90%; oncology: 0.94–17.60% for transient NPSE; epilepsy: 0.31–12%; vascular: 0.40–1.96% and oncology: 0.84–1.48% for permanent NPSE). Regarding permanent NPSE, arguably the most critical consideration, the NPD group showed better outcomes in memory, language and social cognition than the epilepsy group, but worse outcomes in executive and perceptual-motor functions. Compared with the vascular group, the NPD group had better executive function but worse complex attention. Finally, the NPD group had fewer permanent deficits than the oncology group in executive function, complex attention and perceptual-motor domains, although language performance was lower. Conclusions Contemporary NPD apparently carries a similar risk of NPSE as other conventional neurosurgical procedures, challenging misconceptions and this unjustified barrier to its broader use.

The lateral geniculate nucleus (LGN) of the thalamus is a key link between the retina and visual cortex but our understanding of the properties of neurons in the human LGN is based on recordings in animal models. Here we recorded spiking activity of cells in the LGN of two patients who had electrodes implanted in the LGN as part of their treatment for epilepsy. Human LGN cells responded to strong visual stimulation with high-frequency bursts of spikes. The cells had receptive-field properties resembling those of monkeys with circular ON-OFF sub-fields, red-green opponency in the dorsal layers and preferences for high temporal frequencies in the ventral layers. Responses were largely monocular and the closure of one eye decreased the spontaneous activity of broad-spiking neurons preferring this eye while increasing the activity of neurons with narrower spikes, suggesting that interneurons might gate LGN activity during eye closure.

We recorded spiking activity in the human lateral geniculate nucleus (LGN), which links the retina with the primary visual cortex. The cells had receptive-field properties resembling those of monkeys. Responses were largely monocular and the closure of one eye decreased the spontaneous activity of neurons with broader spikes preferring this eye and increased the activity of neurons with narrower spikes, suggesting that interneurons might gate LGN activity during eye closure.

BACKGROUND: Deep brain stimulation (DBS) is commonly used to treat Parkinson's disease (PD) and other movement disorders when other treatments fail. Although DBS can significantly improve motor symptoms, it carries risks such as infections, which can require multiple surgeries and prolonged antibiotic therapy. Research on the long-term neurological effects of DBS-related infections is limited. OBSERVATIONS: A 58-year-old man with a 13-year history of PD, refractory to optimized clinical management, underwent subthalamic nucleus (STN) DBS after previous contralateral lesioning of the posterior subthalamic area. Postoperatively, the DBS lead migrated upward and was repositioned, but he developed perielectrode cerebritis 5 days later. The DBS system was completely removed, and he underwent a 28-day course of intravenous antibiotics. Initially, his motor symptoms remained unchanged, but 4 months later, he experienced a significant and sustained motor symptom improvement that continued until the last follow-up assessment (40 months). Magnetic resonance imaging performed 2 years after the explantation showed gliosis and hemosiderin deposition in the STN, suggesting that the infection-induced gliosis had a lesion-like effect, leading to the observed clinical improvement. LESSONS: This case suggests that infection-induced gliosis from DBS complications can unexpectedly result in long-term motor symptom improvements, potentially influencing future management strategies for similar cases. https://thejns.org/doi/10.3171/CASE24502

Ronald R. Tasker, often called “Ron,” born in Toronto on December 18, 1927, died peacefully near his home on April 19, 2023, at the age of 95 years, after a long and productive life. He was predeceased by his beloved and ever-present wife, Mary M. Tasker (shown in Fig. 1), née Craig, in 2003. He is survived by his children (Moira, James, Ronald, and Alison (shown in Fig. 2)), grandchildren (Gavin, Liam, Kiley, and Quinn), sister (Elizabeth), sister-in-law (Sheila), and a long list of admiring neurosurgeons, who had the privilege to train and learn with him. A celebration of Ron’s life was held in Toronto on June 17, 2023, at the University of Toronto (UofT) Faculty Club.Ron had a deep love of natural history, first nourished as a small boy by exploring the Don River Valley behind his home in East York (Toronto) with his father. Having a precocious mind, Ron entered UofT at age 16 on a classic’s scholarship, graduating in Honours Science (Physiology) at Victoria College (UofT) in 1948 (BA), where he was awarded the Lieutenant Governor’s Medal [1]. Ron’s first and lifelong passion was natural history and the pursuit of field biology, with interests in birds, butterflies, orchids, wildflowers, sedges, and frogs. He pursued these interests with zeal during his travels at home and abroad, frequently accompanied by his wife Mary [1]. Ron reveled in identifying birds worldwide by their markings and songs. He meticulously collected butterflies and plants from around the world. Ron housed his collections at his home office and in his greenhouse. If you were lucky, he would give you a guided tour of the world through his plants and butterflies, which I had the privilege to appreciate (O.V.-F.).Ron was a renowned and active “layman” bird watcher in Canada. Accordingly, he was a member of the Board of Directors (1975–1980, 1982–1990, and 1991–1995) and Chairman (1978–1980, 1983–1987, and 1988–1996) of the Long Point Bird Observatory – Birds Canada; a member of the Executive Board of Directors of the Federation of Ontario Naturalists (1982–1984); and Trustee of The Nature Conservancy of Canada (1987 and 1994) [2]. In 1991, he authored, with Holmes, Hess, and Hanks, The Ontario Butterfly Atlas [3].During his undergraduate studies, Ron worked in the laboratory of Dr. Charles Best, the co-discoverer of insulin, who, together with Ron’s mother, advised him to study medicine. Ron listened, graduating in medicine (MD) from UofT in 1952. He was the recipient of the Saddington Medal in Pathology (1950) and the Cody Silver Medal (1952). Under the tutelage of Dr. Harry Botterell, Ron trained in neurosurgery at UofT from 1953 to 1959 (FRCSC, 1959), during which time he also completed a master’s degree (MA) in physiology (1954). Upon completing his neurosurgical training, Ron made a pilgrimage to Madison, Wisconsin, as a postdoctoral McLaughlin Traveling Fellow to work with the preeminent neurophysiologist Clinton Woolsey, who, to use Ron’s words, taught him to think about the nervous system in an organized fashion. Following his time in Wisconsin, Ron traveled to major functional neurosurgery centers in Paris, Stockholm, and Freiburg, to train with Tailarach, Guiot, Leksell, and Hassler (1959–1961) [1, 2, 4].In 1961, Ron returned to Toronto and joined the staff of the Division of Neurosurgery, Department of Surgery, Toronto General Hospital (TGH), UofT, where he was distinguished as a Markle Scholar (1961–1966), and in 1978 was promoted to Full Professor. Ron taught in the Faculty of Medicine at UofT for over 40 years. He was a very active member of the Graduate Faculty of Medical Science, School of Graduate Studies, and the Playfair Neuroscience Institute from 1978 to 1999, when he became an Emeritus Member [1, 2, 4].Ron headed the Division of Neurosurgery at TGH from 1979 to 1989. The Division of Neurosurgery at TGH was amalgamated in 1989 with the Division of Neurosurgery at Toronto Western Hospital (TWH), under the leadership of Charles Tator. Ron continued his superb work in functional neurosurgery as a senior neurosurgeon at TWH until his retirement in 1998, when he was appointed as honorary staff (shown in Fig. 3) [2, 4]. In the same year, Ron’s wife Mary organized a stereotactic conference in Pond Inlet, Baffin Island, in the Canadian Arctic, to celebrate Ron’s retirement [5]. Ron continued to go to his office following his retirement, once a week on Wednesdays, to see some of his patients who simply refused to see any other doctor [2]. In August 2023, a group of functional neurosurgeons convened in Ilulissat, Greenland, for the most recent Arctic meeting, where Ron’s legacy was once again celebrated [5].Ron was a classically trained scientist in the analog methods of early modern medicine. He pioneered clinical neurophysiology by adopting digital technology and instrumentation in the operating room and by melding his training in neurophysiology and stereotactic neurosurgery. His groundbreaking and meticulous study of the deepest centers of the human brain was enabled by his use of objective, quantifiable metrics and in-house, purpose-built instrumentation and by his assembly of multidisciplinary collaborators [1, 2, 5]. To cite a few of these collaborators, one cannot forget the formidable neuroscientists Leslie Organ, Jonathan Dostrovsky, Bill Hutchison, and Karen Davis. Assisted by these neurophysiologists, Ron mapped the human thalamus and midbrain during stereotactic procedures for pain and movement disorders, relying on macrostimulation. Ron became the world’s pre-eminent brain cartographer, a modern-day Magellan, for his neurophysiological exploration of previously unexplored deep brain targets in humans [1, 2, 4].Derived from these intraoperative studies was one of his most important contributions, The Thalamus and Midbrain of Man, which...

BACKGROUND: Focal aware seizures (FASs) are relatively common and frequently pharmaco-resistant. If the seizure onset zone (SOZ) is in eloquent cortical areas, making resective surgery risky and inadvisable, deep brain stimulation (DBS) of the anterior nucleus of the thalamus, which is efficacious in less than half of the cases, has been the main alternative. New targets should be searched to address this deficiency. The present study aims to determine if DBS of different thalamic specific nuclei can modulate the abnormal electrical activity of the SOZ located in their respective cortical projection areas. Herein, the authors present the first patient in an ongoing trial. OBSERVATIONS: A 60-year-old female patient presented with 25-year history of pharmaco-resistant focal aware visual seizures frequently evolving to focal impaired awareness seizures. The SOZ was in the right occipital lobe (positron emission tomography-computed tomography/video electroencephalography). Magnetic resonance imaging was normal. She underwent ipsilateral lateral geniculate nucleus (LGN) DBS procedure. After a 24-month follow-up, seizure frequency decreased by 97%, improving quality of life and daily functioning without complications. LESSONS: This is the first time the LGN has been targeted in humans. The results support the hypothesis that led to this study. This strategy represents a paradigm shift in the way of treating pharmaco-resistant FASs not amenable to resective surgery.

BACKGROUND: Resection of the seizure onset zone (SOZ) is considered the gold standard for treating refractory focal aware seizures (FASs). When resective surgery is unadvisable, deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT; ANT-DBS) has been the procedure of choice. However, less than half of patients with FASs respond to ANT-DBS. The need for alternative targets to effectively treat FAS is thus evident. OBSERVATIONS: The authors report the case of a 39-year-old woman presenting with pharmaco-resistant focal aware motor seizures, with the SOZ located in the primary motor cortical area. She had previously undergone unsuccessful resection of the left temporoparietal operculum elsewhere. Considering the risk of new resective surgery, she was offered combined ventral intermediate nucleus (Vim)/ANT-DBS. Vim-DBS proved to be superior to ANT-DBS for seizure control (88% vs 32%), although the association of both provided the best results (97%). LESSONS: This is the first report on the use of the Vim as a target of DBS for the treatment of FAS. The excellent results were presumably obtained by modulation of the SOZ through Vim projections to the motor cortex. This opens a completely new avenue for treating FAS: chronic stimulation of specific thalamic nuclei.

Background: Confirmation of whether a stereotactic biopsy was performed in the correct site is usually dependent on the frozen section or on novel tumor-specific markers that are not widely available. Immediate postoperative computed tomography (CT) or magnetic resonance (MR) is routinely performed in our service after biopsy. In this retrospective study, we have carefully analyzed these images in an attempt to determine the presence of markers that indicate appropriate targeting. Methods: Medical records and neuroimages of patients who underwent stereotactic biopsy of intracranial lesions were reviewed. The following variables were assessed: age, sex, anatomopathology, lesion site, complications, diagnostic accuracy, and the presence of image markers. Results: Twenty-nine patients were included in this case series. About 96.6% of the biopsies were accurate according to the permanent section. Of the 86.2% of patients with intralesional pneumocephalus on the postoperative images, 51.7% additionally presented petechial hemorrhage. In 13.8% of the cases, no image markers were identified. Conclusion: This is the first report of intralesional pneumocephalus and petechial hemorrhage as indicators of appropriate targeting in stereotactic biopsy. In the majority of the cases, an immediate postoperative head CT, which is widely available, can estimate how adequate the targeting is. To use intralesional pneumocephalus/ petechial hemorrhages as not only postoperative but also as intraoperative markers of appropriate targeting, it is advised that the surgical wound should be temporarily closed and dressed after the biopsy so that the patient can undergo a CT/MR scan and be checked for the presence of theses markers before removing the stereotactic frame.