Circumscribing Laser Cuts Attenuate Seizure Propagation in a Mouse Model of Focal Epilepsy.

In partial onset epilepsy, seizures arise focally in the brain and often propagate. Patients frequently become refractory to medical management, leaving neurosurgery, which can cause neurologic deficits, as a primary treatment. In the cortex, focal seizures spread through horizontal connections in layers II/III, suggesting that severing these connections can block seizures while preserving function. Focal neocortical epilepsy is induced in mice, sub-surface cuts are created surrounding the seizure focus using tightly-focused femtosecond laser pulses, and electrophysiological recordings are acquired at multiple locations for 3-12 months. Cuts reduced seizure frequency in most animals by 87%, and only 5% of remaining seizures propagated to the distant electrodes, compared to 80% in control animals. These cuts produced a modest decrease in cortical blood flow that recovered and left a ≈20-µm wide scar with minimal collateral damage. When placed over the motor cortex, cuts do not cause notable deficits in a skilled reaching task, suggesting they hold promise as a novel neurosurgical approach for intractable focal cortical epilepsy.

Utility of Virtual Spine Neurosurgery Education for Medical Students.

OBJECTIVE: Distance learning has become increasingly important to expand access to neurosurgical spine education. However, emerging online spine education initiatives have largely focused on residents, fellows, and surgeons in practice. We aimed to assess the utility of online neurosurgical spine education for medical students regarding career interests, knowledge, and technical skills. METHODS: A survey assessing the demographics and effects of virtual spine education programming on the interests, knowledge, and technical skills was sent to attendees of several virtual spine lectures. The ratings were quantified using 7-point Likert scales. RESULTS: A total of 36 responses were obtained, of which 15 (41.7%) were from first- or second-year medical students and 18 (50.0%) were from international students. Most respondents were interested in neurosurgery (n = 30; 80.3%), with smaller numbers interested in radiology (n = 3; 8.3%) and orthopedic surgery (n = 2; 5.6%). The rating of utility ranged from 5.69 ± 1.14 to 6.50 ± 0.81 for career, 5.83 ± 0.94 to 6.14 ± 0.80 for knowledge, and 5.22 ± 1.31 to 5.83 ± 1.06 for clinical skills. Of the 36 respondents, 26 (72.2%) preferred virtual neurosurgical spine education via intermixed lectures and interactive sessions. The most common themes regarding the utility of virtual spine education were radiology by 18 (50.0%), anatomy by 12 (33.3%), and case-based teaching by 8 (22.2%) respondents. CONCLUSIONS: Virtual distance learning for neurosurgical spine education is beneficial for students by enabling career exploration and learning content and clinical skills. Although the overall benefit was lowest for clinical skills, virtual programming could serve as an adjunct to traditional in-person exposure. Distance learning could also provide an avenue to reduce disparities in medical student neurosurgical spine education locally and globally.

Arachnoid cysts: using prenatal imaging and need for pediatric neurosurgical intervention to better understand their natural history and prognosis.

OBJECTIVES: Intracranial arachnoid cysts are commonly characterized as congenital. Evidence to support a congenital origin is scant and documented evolution during infancy also calls into question the genesis of these lesions. To improve our understanding of the natural history and the clinical significance of arachnoid cysts on prenatal ultrasound, we conducted a study to describe the fate of these cysts after initial diagnosis. METHODS: We conducted a retrospective descriptive review of all prenatal ultrasounds with reported intracranial arachnoid cysts at a tertiary care center from 2010 to 2016 and cohort study comparing patients with additional ultrasound abnormalities to those with an isolated finding of arachnoid cyst. Data collected included gestational age at cyst diagnosis, cyst evolution on follow-up imaging, cyst size and cyst location, postnatal imaging and neurosurgical consultation and intervention. Statistical analysis including Chi-square and Fisher's exact tests and univariate logistic regressions were performed using Stata v. 13 (StataCorp 2013. Stata Statistical Software: Release 13. College Station, TX: StataCorp LP). Confidence intervals were reported at 95% and a p-value < .05 was considered significant. RESULTS: A total of 33,621 anatomical ultrasound scans were performed from 2010 to 2016. Seventy patients (0.2%) had prenatal findings of arachnoid cyst, of which the mean gestational age was 21.46 weeks. Ventriculomegaly was observed in one patient (1.4%) at the time of diagnosis and other abnormalities were found in twelve patients (17%). Complete sonographic follow-up prior to delivery was obtained in 53 (75.7%) patients with 5(9.4%) progression, 5(9.4%) regression, and 43(81.1%) no longer visualized. Forty-three cysts (81.1%) were no longer visualized on follow-up imaging, all of which were interhemispheric in location. All of the cysts that progressed in size on prenatal ultrasounds were > 2 cm in size on initial diagnosis. Cyst fenestration was performed in two patients (2.9%) that had arachnoid cysts measuring at least 3 cm in each dimension on prenatal imaging, one at eight months and one at six months of age. Patients with and without additional sonographic abnormalities had similar rates of AMA (23.1% vs 26.3%, p = .56), nulliparity (61.5% vs 70.2%, p = .38), obesity (0.0% vs 12.3%, p = .221), major medical comorbidities (38.5% vs 33.3%, p = .48) and pregnancy achieved via Assisted Reproductive Technology (38.5% vs 24.6%, p = .25), respectively. Patients with additional sonographic abnormalities were significantly more likely to have prenatal Magnetic Resonance Imaging (OR: 8.28, CI: 1.84-40.4, p = .07), prenatal neurosurgery consultation (OR: 8.25, CI: 1.23-69.05, p = .04) and invasive diagnostic genetic testing (OR: 11.25, CI: 2.33-64.35, p = .003). CONCLUSIONS: Arachnoid cysts are infrequently found on prenatal screening. Size greater than 2 cm on second trimester ultrasound and location outside of the interhemispheric fissure may indicate the need for further evaluation and eventual fenestration. Prenatally diagnosed arachnoid cysts are not typically associated with other anatomic or genetic abnormalities, although the presence of additional abnormalities usually leads to more intensive prenatal and postnatal investigations.

Neurosurgery Training Camp for Sub-Internship Preparation: Lessons From the Inaugural Course.

OBJECTIVE: Historically, medical student education in neurological surgery has generally limited student involvement to assisting in research projects with minimal formal clinical exposure before starting sub-internships and application for the neurosurgery match. Consequently, students have generally had little opportunity to acquire exposure to clinical neurosurgery and attain minimal proficiency. A medical student training camp was created to improve the preparation of medical students for the involvement in neurological surgery activities and sub-internships. METHODS: A 1-day course was held at Weill Cornell Medicine, which consisted of a series of morning lectures, an interactive resident lunch panel, and afternoon hands-on laboratory sessions. Students completed self-assessment questionnaires regarding their confidence in several areas of clinical neurosurgery before the start of the course and again at its end. RESULTS: A significant increase in self-assessed confidence was observed in all skill areas surveyed. Overall, rising fourth year students who were starting sub-internships in the subsequent weeks reported a substantial increase in their preparedness for the elective rotations in neurosurgery. CONCLUSIONS: The preparation of medical students for clinical neurosurgery can be improved. Single-day courses such as the described training camp are an effective method for improving knowledge and skill gaps in medical students entering neurosurgical careers. Initiatives should be developed, in addition to this annual program, to increase the clinical and research skills throughout medical student education.

In Vivo Femtosecond Laser Subsurface Cortical Microtransections Attenuate Acute Rat Focal Seizures.

Recent evidence shows that seizures propagate primarily through supragranular cortical layers. To selectively modify these circuits, we developed a new technique using tightly focused, femtosecond infrared laser pulses to make as small as ~100 µm-wide subsurface cortical incisions surrounding an epileptic focus. We use this "laser scalpel" to produce subsurface cortical incisions selectively to supragranular layers surrounding an epileptic focus in an acute rodent seizure model. Compared with sham animals, these microtransections completely blocked seizure initiation and propagation in 1/3 of all animals. In the remaining animals, seizure frequency was reduced by 2/3 and seizure propagation reduced by 1/3. In those seizures that still propagated, it was delayed and reduced in amplitude. When the recording electrode was inside the partially isolated cube and the seizure focus was on the outside, the results were even more striking. In spite of these microtransections, somatosensory responses to tail stimulation were maintained but with reduced amplitude. Our data show that just a single enclosing wall of laser cuts limited to supragranular layers led to a significant reduction in seizure initiation and propagation with preserved cortical function. Modification of this concept may be a useful treatment for human epilepsy.

Running-to-Interrupted Microsuture Technique for Vascular Bypass.

BACKGROUND: The ideal suturing technique for microvascular anastomosis for neurosurgical bypass procedures remains a point of debate. Simple interrupted sutures are thought to possess higher long-term patency but require more time to place as compared to running sutures. OBJECTIVE: To optimize the efficiency of microvascular anastomosis and limit brain ischemia time. METHODS: The running-to-interrupted microsuture technique, a modification of the previously published spiral anastomosis, is described wherein loosely thrown running sutures are placed between 2 opposed anchor stitches. The loops are then serially cut and tied, resulting in efficiently placed interrupted stitches. This process is repeated on the opposite side to complete the anastomosis. RESULTS: The running-to-interrupted microsuture technique is quickly learned, limits unnecessary microsurgical movements, and is employed by the senior author for a multitude of cerebral arterial bypass procedures. CONCLUSION: This technical improvement can be adapted by any neurovascular surgeon to optimize microsurgical efficiency and limit anastomosis-related brain ischemia times.

Neuroprotective strategies following intraparenchymal hemorrhage.

Intracerebral hemorrhage and, more specifically, intraparenchymal hemorrhage, are devastating disease processes with poor clinical outcomes. Primary injury to the brain results from initial hematoma expansion while secondary hemorrhagic injury occurs from blood-derived products such as hemoglobin, heme, iron, and coagulation factors that overwhelm the brains natural defenses. Novel neuroprotective treatments have emerged that target primary and secondary mechanisms of injury. Nonetheless, translational application of neuroprotectants from preclinical to clinical studies has yet to show beneficial clinical outcomes. This review summarizes therapeutic agents and neuroprotectants in ongoing clinical trials aimed at targeting primary and secondary mechanisms of injury after intraparenchymal hemorrhage.