IntroductionRecently, there has been a paradigm shift in the management of hypothalamic hamartoma (HH) from traditional microsurgical techniques to less invasive alternatives such as stereotactic radiosurgery and laser interstitial thermal therapy. However, large and extensive HH may fail to respond to minimally invasive therapies, ultimately necessitating microsurgery.MethodsAll patients who underwent microsurgical resection of a complex HH by the 2 senior authors (D.J.L., H.L.R.) in 2011-2017 were included. Charts were retrospectively reviewed and demographic, clinical, imaging, and outcome data were recorded.Results8 patients, 7 children and 1 adult, with a mean age of 7 years (10 months-27 years), were included. Of those, 2 had failed previous treatments. All 7 children presented with pharmacoresistant gelastic seizures and cognitive dysfunction, 6 exhibited central precocious puberty, and 3 had behavioral problems. Other seizure types affected 6/8 patients. Mean lesion size was 21.6 mm (14-31), all with interpeduncular extension and 5 with intraventricular extension (Delalande type I: 3, type III: 4, type IV: 1). A frontotemporal orbitozygomatic (FTOZ) approach with optic nerve decompression was used in all patients, supplemented by another approach in 3 (endoscopic transventricular: 3, transcallosal: 1). Gross total resection was achieved in 6 patients and subtotal resection in 2. Transient complications occurred in 3 patients (37.5%): self-limited sodium imbalance (n=3), subdural hygroma (n=2). Permanent complications occurred in 2 patients (25%): perforator infarct (n=1), short-term memory loss (n=1). All patients experienced seizure resolution postoperatively with preserved hypothalamic-pituitary axis function. After a mean follow-up of 41 months (2-66), 7 patients remain seizure-free, while 1 has rare recurrent seizures. Cognitive and behavioral symptoms improved significantly in all patients.ConclusionFor large HH with interpeduncular extension, microsurgery via the FTOZ approach is a safe and highly effective treatment modality.

ObjectiveDisconnection of the cerebral hemispheres by corpus callosotomy (CC) is an established means to palliate refractory generalized epilepsy. Laser interstitial thermal therapy (LITT) is gaining acceptance as a minimally invasive approach to treating epilepsy, but this method has not been evaluated in clinical series using established methodologies to assess connectivity. The goal in this study was to demonstrate the safety and feasibility of MRI-guided LITT for CC and to assess disconnection by using electrophysiology- and imaging-based methods.MethodsRetrospective chart and imaging review was performed in 5 patients undergoing LITT callosotomy at a single center. Diffusion tensor imaging and resting functional MRI were performed in all patients to assess anatomical and functional connectivity. In 3 patients undergoing simultaneous intracranial electroencephalography monitoring, corticocortical evoked potentials and resting electrocorticography were used to assess electrophysiological correlates.ResultsAll patients had generalized or multifocal seizure onsets. Three patients with preoperative evidence for possible lateralization underwent stereoelectroencephalography depth electrode implantation during the perioperative period. LITT ablation of the anterior corpus callosum was completed in a single procedure in 4 patients. One complication involving misplaced devices required a second procedure. Adequacy of the anterior callosotomy was confirmed using contrast-enhanced MRI and diffusion tensor imaging. Resting functional MRI, corticocortical evoked potentials, and resting electrocorticography demonstrated functional disconnection of the hemispheres. Postcallosotomy monitoring revealed lateralization of the seizures in all 3 patients with preoperatively suspected occult lateralization. Four of 5 patients experienced > 80% reduction in generalized seizure frequency. Two patients undergoing subsequent focal resection are free of clinical seizures at 2 years. One patient developed a 9-mm intraparenchymal hematoma at the site of entry and continued to have seizures after the procedure.ConclusionsMRI-guided LITT provides an effective minimally invasive alternative method for CC in the treatment of seizures associated with drop attacks, bilaterally synchronous onset, and rapid secondary generalization. The disconnection is confirmed using anatomical and functional neuroimaging and electrophysiological measures.

BACKGROUND: The operative microscope has significantly advanced modern neurosurgical spine surgery but continues to be limited by high costs, suboptimal optics, poor ergonomics, and difficulties with maneuverability. We believe the novel 4K high-definition (4K-HD) 3-dimensional (3D) exoscope (EX), may improve the surgical corridor through advancements in illumination, ergonomics, magnification, and depth of field and has the potential to be utilized in neurosurgical education and training. OBJECTIVE: To evaluate the surgical potential of a novel 3D EX system in spinal surgery. METHODS: Retrospective analysis over 6 mo of all patients who have undergone spinal surgery at Northwell Health using the 3D EX. Nuances of surgical theater positioning, advantages/disadvantages of the EX and clinical sequelae of the patients were analyzed. RESULTS: All 10 patients who underwent spinal surgery utilizing the EX experienced excellent surgical and clinical outcomes without complications. The low-profile EX allowed for excellent operative corridors and instrument maneuverability. The large monitor also resulted in an immersive surgical experience, and gave team members the same 3D vision as the operator. CONCLUSION: This study demonstrates the feasibility of utilizing the 3D 4K-HD EX system and highlights potential technical assets of this novel technology in regard to optics, ergonomics, and maneuverability. Further clinical research is needed to examine the clinical effectiveness of the EX system for different surgical approaches through quantitative methodology.

BACKGROUND:Cerebral bypass operation is a technically challenging operation that requires excellent surgical visibility and efficient ergonomics to minimize complications and maximize successful revascularization. Despite the operative microscope's utilization for the past two generations, there remains a need for continued improvement in operative visualization and surgical ergonomics. OBJECTIVE:To report the positives and negatives of our initial experience using a novel 4 K high-definition (4K-HD) 3-dimensional (3D) exoscope (EX) for cranial bypass surgery. METHODS:A retrospective review over 6 mo was performed of all patients who have undergone cerebral bypass surgery at a single institution using the 4K-HD 3D EX. Advantages and disadvantages of the EX and clinical outcome of the patients were assessed. RESULTS:A total of 5 patients underwent cerebral EC-IC bypass surgery with no EX-related complications and successful revascularization. The lightweight design of the EX allowed for easy instrument maneuverability as well as uncomplicated surgical set up in the operating room. The assistance of the cosurgeon was significantly more efficient compared to that of the operating microscope. The large monitor allowed for an immersive, collaborative, and valuable educational surgical experience. CONCLUSION:Using the EX for cerebral bypass surgery, with 3D ultra-high-definition optics, enhancements of ergonomics, and improved training, we believe that the 3D 4K-HD EX may represent the next generation of operative scopes in microneurosurgery.

Management of cerebrospinal fluid (CSF) leak during minimally invasive lumbar tubular microdiscectomy poses challenges unique to the surgical approach. Primary repair can be limited via tubular retractor systems, and onlay graft and dural sealant are often the treatment of choice intraoperatively. Postoperative persistent CSF leak may lead to intracranial hypotension (IH) and positional headaches. Early epidural blood patch (EBP) efficacy in the treatment of spinal CSF leaks of both spontaneous and iatrogenic origin is well-established in numerous studies. However, there is no consensus on treatment of persistent IH symptoms for patients undergoing lumbar tubular microdiscectomy. We describe the clinical courses of two patients who were treated with early EBP for IH symptoms following CSF leak during tubular microdiscectomy. Both patients underwent intraoperative repair with onlay autologous tissue graft followed by dural sealant after discectomy was completed without evidence of pseudomeningocele, but they developed postoperative positional headaches and presumed IH. Both patients received an early EBP with an immediate and complete resolution of positional headaches sparing them reoperation and/or lumbar drainage. EBP should be considered as a first-line treatment to treat postoperative IH symptoms without pseudomeningocele after iatrogenic CSF leak during tubular microdiscectomy.

How does human brain stimulation result in lasting changes in cortical excitability? Uncertainty on this question hinders the development of personalized brain stimulation therapies. To characterize how cortical excitability is altered by stimulation, we applied repetitive direct electrical stimulation in eight human subjects (male and female) undergoing intracranial monitoring. We evaluated single-pulse corticocortical-evoked potentials (CCEPs) before and after repetitive stimulation across prefrontal (n = 4), temporal (n = 1), and motor (n = 3) cortices. We asked whether a single session of repetitive stimulation was sufficient to induce excitability changes across distributed cortical sites. We found a subset of regions at which 10 Hz prefrontal repetitive stimulation resulted in both potentiation and suppression of excitability that persisted for at least 10 min. We then asked whether these dynamics could be modeled by the prestimulation connectivity profile of each subject. We found that cortical regions (1) anatomically close to the stimulated site and (2) exhibiting high-amplitude CCEPs underwent changes in excitability following repetitive stimulation. We demonstrate high accuracy (72–95%) and discriminability (81–99%) in predicting regions exhibiting changes using individual subjects' prestimulation connectivity profile, and show that adding prestimulation connectivity features significantly improved model performance. The same features predicted regions of modulation following motor and temporal cortices stimulation in an independent dataset. Together, baseline connectivity profile can be used to predict regions susceptible to brain changes and provides a basis for personalizing brain stimulation. SIGNIFICANCE STATEMENT Brain stimulation is increasingly used to treat neuropsychiatric disorders by inducing excitability changes at specific brain regions. However, our understanding of how, when, and where these changes are induced is critically lacking. We inferred plasticity in the human brain after applying electrical stimulation to the brain's surface and measuring changes in excitability. We observed excitability changes in regions anatomically and functionally closer to the stimulation site. Those in responsive regions were accurately predicted using a classifier trained on baseline brain network characteristics. Finally, we showed that the excitability changes can potentially be monitored in real-time. These results begin to fill basic gaps in our understanding of stimulation-induced brain dynamics in humans and offer pathways to optimize stimulation protocols.

Successful treatment of hypothalamic hamartoma (HH) can result in the resolution of its sequelae including epilepsy and rage attacks. Risks and morbidity of open surgical management of this lesion have motivated the development of laser interstitial thermal therapy (LITT) as a less invasive treatment approach to the disease. Although overall morbidity and risk would appear to be lower, complications related to LITT therapy have been reported, and the longer-term follow-up that is now possible after initial experience helps address the question of whether LITT provides equivalent efficacy compared to other treatment options. We conducted a retrospective analysis of clinical outcomes in eight patients undergoing LITT for HH at our center using the Visualase/Medtronic device. Five patients had refractory epilepsy, one had rage attacks, and two had both. We also compared the published seizure-free outcomes over time and the complication rates for different interventional approaches to the treatment of epilepsy due to HH including open craniotomy, neuroendoscopic, radiosurgical, and radiofrequency approaches. With a mean follow-up of 19.1months in our series of eight patients, six of seven epilepsy patients achieved seizure freedom, whereas the one patient with rage attacks only did not have improvement of his symptoms. A length of hospital stay of 2.6days reflects low morbidity and rapid postoperative recuperation with LITT. Considering other reported series and case reports, the overall published seizure freedom rate of 21 of 25 patients is superior to published outcomes of HH cases treated by stereotactic radiosurgery (SRS), craniotomy, or neuroendoscopy, and comparable to radiofrequency ablation. The cumulative experience of our center with other published series supports relatively lower operative morbidity than more invasive approaches and efficacy that is as good or better than open craniotomy procedures and SRS. Although morbidity appears to be lower than other open approaches, complications related to LITT and their avoidance should be considered carefully.

Transcranial magnetic stimulation (TMS) targeting the left dorsolateral prefrontal cortex (dlPFC) is a commonly-used treatment for depression. However, our understanding of the mechanism by which TMS exerts its antidepressant effect is limited.

BACKGROUND:Mycobacterium abscessus is a rapidly growing atypical mycobacterium implicated in chronic lung disease, otitis media, surgical site infections, and disseminated cutaneous diseases. It is typically seen in patients with some degree of immunosuppression. Only 1 previous case has been reported in the setting of ventriculoperitoneal (VP) shunt infection. We report a case of M abscessus as the causative organism in a VP shunt infection in an immunocompetent adult.CASE DESCRIPTION:A 67-year-old woman required VP shunt placement after aneurysmal subarachnoid hemorrhage complicated by hydrocephalus. Her course was complicated by repeat hospitalization for 2 shunt infections, the second of which did not respond to standard antibiotic therapy. Cultures repeatedly grew M abscessus. The patient continued to decline and eventually died after transfer to the palliative care service.CONCLUSIONS:Nontuberculous mycobacteria are rare, atypical organisms in the setting of VP shunt infection. Patients with ventriculitis secondary to atypical mycobacteria may exhibit drug-resistant cerebrospinal fluid pleocytosis in the face of standard antibiotic regimens.