Investigating Deep Brain Stimulation of the Habenula: A Review of Clinical Studies.

OBJECTIVES: The aim of this study was to examine the current scientific literature on deep brain stimulation (DBS) targeting the habenula for the treatment of neuropsychiatric disorders including schizophrenia, major depressive disorder, and obsessive-compulsive disorder (OCD). MATERIALS AND METHODS: Two authors performed independent data base searches using the PubMed, Cochrane, PsycINFO, and Web of Science search engines. The data bases were searched for the query ("deep brain stimulation" and "habenula"). The inclusion criteria involved screening for human clinical trials written in English and published from 2007 to 2020. From the eligible studies, data were collected on the mean age, sex, number of patients included, and disorder treated. Patient outcomes of each study were summarized. RESULTS: The search yielded six studies, which included 11 patients in the final analysis. Treated conditions included refractory depression, bipolar disorder, OCD, schizophrenia, and major depressive disorder. Patients with bipolar disorder unmedicated for at least two months had smaller habenula volumes than healthy controls. High-frequency stimulation of the lateral habenula attenuated the rise of serotonin in the dorsal raphe nucleus for treating depression. Bilateral habenula DBS and patient OCD symptoms were reduced and maintained at one-year follow up. Low- and high-frequency stimulation DBS can simulate input paths to the lateral habenula to treat addiction, including cocaine addiction. More data are needed to draw conclusions as to the impact of DBS for schizophrenia and obesity. CONCLUSIONS: The habenula is a novel target that could aid in reducing neuropsychiatric symptoms and should be considered in circuit-specific investigation of neuromodulation for psychiatric disorders. More information needs to be gathered and assessed before this treatment is fully approved for treatment of neuropsychiatric conditions.

Transcriptional expression changes during compensatory plasticity in the terminal ganglion of the adult cricket Gryllus bimaculatus.

BACKGROUND: Damage to the adult central nervous system often leads to long-term disruptions in function due to the limited capacity for neurological recovery. The central nervous system of the Mediterranean field cricket, Gryllus bimaculatus, shows an unusual capacity for compensatory plasticity, most obviously in the auditory system and the cercal escape system. In both systems, unilateral sensory disruption leads the central circuitry to compensate by forming and/or strengthening connections with the contralateral sensory organ. While this compensatory plasticity in the auditory system relies on robust dendritic sprouting and novel synapse formation, the compensatory plasticity in the cercal escape circuitry shows little obvious dendritic sprouting and instead may rely on shifts in excitatory and inhibitory synaptic strength. RESULTS: In order to better understand what types of molecular pathways might underlie this compensatory shift in the cercal system, we used a multiple k-mer approach to assemble a terminal ganglion transcriptome that included ganglia collected one, three, and 7 days after unilateral cercal ablation in adult, male animals. We performed differential expression analysis using EdgeR and DESeq2 and examined Gene Ontologies to identify candidates potentially involved in this plasticity. Enriched GO terms included those related to the ubiquitin-proteosome protein degradation system, chromatin-mediated transcriptional pathways, and the GTPase-related signaling system. CONCLUSION: Further exploration of these GO terms will provide a clearer picture of the processes involved in compensatory recovery of the cercal escape system in the cricket and can be compared and contrasted with the distinct pathways that have been identified upon deafferentation of the auditory system in this same animal.

Eagle syndrome: a rare pathology presented in a 3-Dimensional reconstructed view.

A 42-year-old male presented with 3-month history of constant right-sided frontal headaches, severe right-sided intermittent sharp jaw pain, odynophagia, globus pharyngis, and worsening episodes of blurry vision in his right eye. Cervicocerebral angiography demonstrated a prominent, 4 cm right sided styloid process with close proximity to the right internal carotid artery (ICA). The patient was referred to otorhinolaryngology for styloidectomy and continued care.

Resolution of hypoglossal nerve palsy after coil embolization of an anterior condylar confluence fistula.

A 69-year-old female presented with 2-year history of slurred speech, left-sided pulsatile tinnitus, and left-sided hypoglossal nerve palsy. Cerebral angiography demonstrated a left anterior condylar confluence fistula. She was treated with a transvenous coil embolization of the left condylar fistula pocket.

Financial barriers and inequity in medical education in India: challenges to training a diverse and representative healthcare workforce.

India has been historically challenged by an insufficient and heterogeneously clustered distribution of healthcare infrastructure. While resource-limited healthcare settings, such as major parts of India, require multidisciplinary approaches for improvement, one key approach is the recruitment and training of a healthcare workforce representative of its population. This requires overcoming barriers to equity and representation in Indian medical education that are multi-faceted, historical, and rooted in inequality. However, literature is lacking regarding the financial or economic barriers, and their implications on equity and representation in the Indian allopathic physician workforce, which this review sought to describe. Keyword-based searches were carried out in PubMed, Google Scholar, and Scopus in order to identify relevant literature published till November 2023. This state-of-the-art narrative review describes the existing multi-pronged economic barriers, recent and forthcoming changes deepening these barriers, and how these may limit opportunities for having a diverse workforce. Three sets of major economic barriers exist to becoming a specialized medical practitioner in India - resources required to get selected into an Indian medical school, resources required to pursue medical school, and resources required to get a residency position. The resources in this endeavor have historically included substantial efforts, finances, and privilege, but rising barriers in the medical education system have worsened the state of inequity. Preparation costs for medical school and residency entrance tests have risen steadily, which may be further exacerbated by recent major policy changes regarding licensing and residency selection. Additionally, considerable increases in direct and indirect costs of medical education have recently occurred. Urgent action in these areas may help the Indian population get access to a diverse and representative healthcare workforce and also help alleviate the shortage of primary care physicians in the country. Discussed are the reasons for rural healthcare disparities in India and potential solutions related to medical education.

The US Residency Selection Process After the United States Medical Licensing Examination Step 1 Pass/Fail Change: Overview for Applicants and Educators.

The United States Medical Licensing Examination (USMLE) Step 1, arguably the most significant assessment in the USMLE examination series, changed from a 3-digit score to a pass/fail outcome in January 2022. Given the rapidly evolving body of literature on this subject, this paper aims to provide a comprehensive review of the historical context and impact of this change on various stakeholders involved in residency selection. For this, relevant keyword-based searches were performed in PubMed, Google Scholar, and Scopus to identify relevant literature. Given the unique history of USMLE Step 1 in the US residency selection process and the score's correlation with future performance in board-certifying examinations in different specialties, this scoring change is predicted to significantly impact US Doctor of Medicine students, US Doctor of Osteopathic Medicine students, international medical graduates, and residency program directors, among others. The significance and the rationale of the pass/fail change along with the implications for both residency applicants and educators are also summarized in this paper. Although medical programs, academic institutions, and residency organizing bodies across the United States have swiftly stepped up to ensure a seamless transition and have attempted to ensure equity for all, the conversion process carries considerable uncertainty for residency applicants. For educators, the increasing number of applications conflicts with holistic application screening, leading to the expected greater use of objective measures, with USMLE Step 2 Clinical Knowledge likely becoming the preferred screening tool in lieu of Step 1.

Household income is associated with return to surgery following discectomy for far lateral disc herniation.

BACKGROUND: Numerous studies have demonstrated that household income is independently predictive of postsurgical morbidity and mortality, but few studies have elucidated this relationship in a purely spine surgery population. This study aims to correlate household income with adverse events after discectomy for far lateral disc herniation (FLDH). METHODS: All adult patients (N.=144) who underwent FLDH surgery at a single, multihospital, 1659-bed university health system (2013-2020) were retrospectively analyzed. Univariate logistic regression was used to evaluate the relationship between household income and adverse postsurgical events, including unplanned hospital readmissions, ED visits, and reoperations. RESULTS: Mean age of the population was 61.72±11.55 years. Mean household income was $78,283±26,996; 69 (47.9%) were female; and 126 (87.5%) were non-Hispanic white. Ninety-two patients underwent open and fifty-two underwent endoscopic FLDH surgery. Each additional dollar decrease in household income was significantly associated with increased risk of reoperation of any kind within 90-days, but not 30-days, after the index admission. However, household income did not predict risk of readmission or ED visit within either 30-days or 30-90-days postsurgery. CONCLUSIONS: These findings suggest that household income may predict reoperation following FLDH surgery. Additional research is warranted into the relationship between household income and adverse neurosurgical outcomes.

Varying Degree of Overlap Following the Critical Steps of Lumbar Fusion and Short-term Outcomes.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: The present study analyzes the impact of end-overlap on short-term outcomes after single-level, posterior lumbar fusions. SUMMARY OF BACKGROUND DATA: Few studies have evaluated how "end-overlap" (i.e., surgical overlap after the critical elements of spinal procedures, such as during wound closure) influences surgical outcomes. METHODS: Retrospective analysis was performed on 3563 consecutive adult patients undergoing single-level, posterior-only lumbar fusion over a 6-year period at a multi-hospital university health system. Exclusion criteria included revision surgery, missing key health information, significantly elevated body mass index (>70), non-elective operations, non-general anesthesia, and unclean wounds. Outcomes included 30-day emergency department visit, readmission, reoperation, morbidity, and mortality. Univariate analysis was carried out on the sample population, then limited to patients with end-overlap. Subsequently, patients with the least end-overlap were exact-matched to patients with the most. Matching was performed based on key demographic variables-including sex and comorbid status-and attending surgeon, and then outcomes were compared between exact-matched cohorts. RESULTS: Among the entire sample population, no significant associations were found between the degree of end-overlap and short-term adverse events. Limited to cases with any end-overlap, increasing overlap was associated with increased 30-day emergency department visits ( P =0.049) but no other adverse outcomes. After controlling for confounding variables in the demographic-matched and demographic/surgeon-matched analyses, no differences in outcomes were observed between exact-matched cohorts. CONCLUSIONS: The degree of overlap after the critical steps of single-level lumbar fusion did not predict adverse short-term outcomes. This suggests that end-overlap is a safe practice within this surgical population.

Interhemispheric gravity-assisted approach for microsurgical resection of a splenium arteriovenous malformation.

The parietal interhemispheric approach employing gravity retraction with skeletonization of bridging veins provides an excellent operative window for safe, curative resection of splenial arteriovenous malformations.

Increasing Nonconcurrent Overlapping Surgery Is Not Associated With Outcome Changes in Lumbar Fusion.

BACKGROUND: There remains a paucity of literature on the impact of overlap on neurosurgical patient outcomes. The purpose of the present study was to correlate increasing duration of surgical overlap with short-term patient outcomes following lumbar fusion. METHODS: The present study retrospectively analyzed 1302 adult patients undergoing overlapping, single-level, posterior-only lumbar fusion within a single, multicenter, academic health system. Recorded outcomes included 30-day emergency department visits, readmission, reoperation, mortality, overall morbidity, and overall morbidity/surgical complications. The amount of overlap was calculated as a percentage of total overlap time. Comparison was made between patients with the most (top 10%) and least (bottom 40%) amount of overlap. Patients were then exact matched on key demographic factors but not by the attending surgeons. Subsequently, patients were exact matched by both demographic data and the attending surgeons. Univariate analysis was first carried out prior to matching and then on both the demographic-matched and surgeon-matched cohorts. Significance for all analyses was set at a P value of <0.05. RESULTS: Within the whole population, increasing duration of overlap was not correlated with any short-term outcome (P = 0.41-0.91). After exact matching, patients with the most and least durations of overlap did not have significant differences with respect to any short-term outcomes (P = 0.34-1.00). CONCLUSION: Increased amount of overlap is not associated with adverse short-term outcomes for single-level, posterior-only lumbar fusions. CLINICAL RELEVANCE: The present results suggest that increasing the duration of overlap during lumbar fusion surgery does not lead to inferior outcomes.

Postoperative outcomes and the association with overlap before or after the critical step of lumbar fusion.

OBJECTIVE: This study assesses how degree of overlap, either before or after the critical operative portion, affects lumbar fusion outcomes. METHODS: The authors retrospectively studied 3799 consecutive patients undergoing single-level, posterior-only lumbar fusion over 6 years (2013-2019) at a university health system. Outcomes recorded within 30-90 and 0-90 postoperative days included emergency department (ED) visit, readmission, reoperation, overall morbidity, and mortality. Furthermore, morbidity and mortality were recorded for the duration of follow-up. The amount of overlap that occurred before or after the critical portion of surgery was calculated as a percentage of total beginning or end operative time. Subsequent to initial whole-population analysis, coarsened exact-matched cohorts of patients were created with the least and most amounts of either beginning or end overlap. Univariate analysis was performed on both beginning and end overlap exact-matched cohorts, with significance set at p < 0.05. RESULTS: Equivalent outcomes were observed when comparing exact-matched patients. Among the whole population, the degree of beginning overlap was correlated with reduced ED visits within 30-90 and 0-90 days (p = 0.007, p = 0.009; respectively), and less 0-90 day morbidity (p = 0.037). Degree of end overlap was correlated with fewer 30-90 day ED visits (p = 0.015). When comparing only patients with overlap, degree of beginning overlap was correlated with fewer 0-90 day reoperations (p = 0.022), and no outcomes were correlated with degree of end overlap. CONCLUSIONS: The degree of overlap before or after the critical step of surgery does not lead to worse outcomes after lumbar fusion.

Trends in Matriculation from Neurological Surgery Training Programs into Academic Versus Private Practice.

OBJECTIVE: A career in academic neurosurgery is an arduous endeavor. Specific factors influencing physician practice preferences remain unclear. This study analyzes data from the American Association of Neurological Surgeons membership identifying the impact of several demographic and educational characteristics influencing neurosurgical career choices centered on academia, private practice, or a combination in the United States. METHODS: A list of all current neurosurgeons was obtained from the American Association of Neurological Surgeons membership, and information on physician characteristics was collected via internet searches and institutional databases. The practice type of all neurosurgeons considered in this study were categorized as follows: private practice, academic, or a combination of private practice and academic, termed privademic. These data were subsequently correlated to race, gender, current age, training at a top 40 National Institutes of Health-funded medical school or residency program, and current practice. RESULTS: The median age of private practice and academic neurosurgeons was 58.18 and 53.61 years, respectively (P < 0.001). Age was significantly associated with practicing in an academic setting (odds ratio 0.96), with younger neurosurgeons pursuing careers in academia. Data indicated a positive and statistically significant contribution of female gender (P < 0.001) and training at a top-40 National Institutes of Health-funded institution to practicing in an academic setting (P < 0.01). CONCLUSIONS: Neurosurgery as a field has grown significantly over the past century. The authors recommend that future efforts seek to diversify the neurosurgical workforce by considering practice setting, demographic characteristics, and educational background.

Application of Advanced Technology During Resection of Posterior Fossa Arteriovenous Malformations: 2 Sister Cases.

Various advanced imaging and intraoperative technologies can be used during resection of posterior fossa arteriovenous malformations (AVMs) in a hybrid neurovascular operating room. These technologies include transradial intraoperative angiography with post-processing of angiographic data for navigation (in combination with stereotactic magnetic resonance imaging) (Figure 1). Advanced semiautomated processing allows magnetic resonance imaging, computed tomography angiography, and angiography fusion for enhanced localization of the AVM. Additional useful technologies include processing of angiographic transit time to provide valuable flow data, indocyanine green angiography, fluorescein angiography, and use of a high-definition endoscope. While these technologies are potentially useful in certain circumstances, they may not be necessary in the case of relatively straightforward vascular lesions. Keeping this in mind is of particular importance, as the use of these technologies may require extended time with the patient under anesthesia. These sister cases of cerebellar AVMs illustrate the spectrum of the advanced technologies that are potentially available to surgeons during posterior fossa AVM resection (Video 1).

Microsurgical Clip Reconstruction of a Ruptured Internal Carotid Artery Terminus Blister Aneurysm Using a Reverse Picket Fence Technique.

BACKGROUND: Blister aneurysms are rare, technically challenging lesions that are typically ill defined and arise at nonbranch points of arteries. OBJECTIVE: To describe the microsurgical treatment of a ruptured blister aneurysm at the internal carotid artery (ICA) terminus using the reverse picket fence clipping technique. METHODS: The patient was a 60-yr-old male. He presented with a Hunt and Hess Grade 2, Fisher Grade 3 subarachnoid hemorrhage located in the bilateral sylvian fissures (right > left) and suprasellar cisterns. Computed tomography angiography demonstrated 2 aneurysms: a 2-mm right middle cerebral artery (MCA) aneurysm and a 2.5-mm right internal carotid artery (ICA) terminus blister aneurysm. Transradial cerebral angiography was undertaken which showed these similar sized aneurysms. Microsurgical treatment was chosen, and the patient underwent a right pterional craniotomy for clipping of his aneurysms. The patient consented to the procedure. RESULTS: The combination of stacked fenestrated clips repaired the vessel, with intraoperative fluorescein and indocyanine green angiography demonstrated normal filling of the MCA and ICA circulation with no delay. Intraoperative angiography confirmed induced moderate stenosis of the ICA terminus at about 50%, which is essential to close the blister aneurysm site by utilizing a portion of the normal vessel wall. CONCLUSION: Ruptured blister aneurysms at the ICA terminus can be safely repaired using the reverse picket fence technique for clipping.

Combined Endovascular and Microsurgical Management of a Tentorial Arteriovenous Malformation in a Hybrid Neurovascular Operating Room: 2-Dimensional Operative Video.

Tentorial margin arteriovenous malformations (AVMs) at the cerebello-mesencephalic fissure are deep lesions, which can be safely resected via a lateral supracerebellar infratentorial approach. This video illustrates the case of a patient who presented with hemorrhage from a tentorial AVM. He was managed in the hybrid neurovascular operating room with Onyx (Medtronic) embolization of a superior cerebellar artery feeder followed by resection of the AVM, which included cerebellar relaxation from lumbar cerebrospinal fluid (CSF) drainage and lateral positioning. Wide cisternal arachnoid dissection at the quadrigeminal cistern allowed for a straight trajectory to the AVM without fixed retraction. Intraoperative transradial angiography confirmed complete AVM exclusion. This video was deemed Institutional Review Board (IRB) exempt by the University of Pennsylvania IRB as it is considered a case report, which does not require IRB approval or patient consent. The patient consented to the procedure.

Case Series of Ultrasonic Navigated Osteotomy for the Treatment of Spinal Chordomas.

BACKGROUND: Chordomas present challenges for en bloc surgical resection, which optimally reduces local recurrence and increases patient survival. Navigated ultrasonic osteotomy, also known as piezosurgery, provides a distinct advantage for achieving negative margins after en bloc resection. METHODS: Eight consecutive patients with chordomas (2 cervical, 3 lumbar, and 3 sacral) treated with navigated ultrasonic osteotomy to achieve en bloc resection were identified from our institutional spine tumor database (2016-2019) and retrospectively reviewed. RESULTS: En bloc resection, with negative margins, was achieved in all cases. Two patients (25%) were women, and mean age at surgery was 44 ± 11 years. Median estimated blood loss was 1000 mL (interquartile range: 263-1500 mL). Median length of hospital stay was 10 days (interquartile range: 3-19.5 days). Two patients required a revision procedure. Two patients had complications requiring readmission within the 30-day postoperative window. Mean duration of follow-up for the cohort was 900 ± 554 days. CONCLUSIONS: Navigated ultrasonic osteotomy is an effective surgical technique to achieve en bloc resection of chordomas with negative margins and disease-free survival. To date, this represents the first reported cohort of patients undergoing the procedure as described here. Future studies should include larger sample sizes for more robust clinical outcome data to further elucidate the benefits of piezosurgery for obtaining en bloc chordoma resection.

Social Determinants of Health and Neurosurgical Outcomes: Current State and Future Directions.

The relationship between social determinants of health (SDOH) and neurosurgical outcomes has become increasingly relevant. To date, results of prior work evaluating the impact of social determinants in neurosurgery have been mixed, and the need for robust data on this subject remains. The present review evaluates how gender, race, and socioeconomic status (SES) influence outcomes following various brain tumor resection procedures. Results from a number of prior studies from the senior author's lab are summarized, with all data acquired using the EpiLog tool (Epilog Laser). Separate analyses were performed for each procedure, evaluating the unique, isolated impact of gender, race, and SES on outcomes. A comprehensive literature review identified any prior studies evaluating the influence of these SDOH on neurosurgical outcomes. The review presented herein suggests that the effect of gender and race on outcomes is largely mitigated when equal access to care is attained, and socioeconomic factors and comorbidities are controlled for. Furthermore, when patients are matched upon for a number of clinically relevant covariates, SES impacts postoperative mortality. Elucidation of this disparity empowers surgeons to initiate actionable change to equilibrate future outcomes.