Cranial and Spinal Cerebrospinal Fluid Leaks: Foundations of Identification and Management.

Cerebrospinal fluid (CSF) leaks may occur at the skull base or along the spinal column and can cause a variety of debilitating neurological symptoms for patients. Recognizing the potential presence of a CSF leak and then identifying its source are necessary for accurate diagnosis and definitive treatment. A standardized workflow can be followed for successful leak localization, which often requires several diagnostic studies, and for definitive leak treatment, which can range from minimally invasive, needle-based approaches to a variety of surgical corrections. This review paper provides an overview of epidemiology, pathophysiology, and diagnostic workup for CSF leaks and introduces available treatment options. An illustrative case of a skull base CSF leak demonstrating diagnosis and surgical correction is provided.

The Endoscopic Lateral Transorbital Approach for the Removal of Select Sphenoid Wing and Middle Fossa Meningiomas. Surgical Technique and Short-Term Outcomes.

BACKGROUND AND OBJECTIVE: The endoscopic lateral transorbital approach (eLTOA) is a relatively new approach to the skull base that has only recently been applied in vivo in the management of complex skull base pathology. Most meningiomas removed with this approach have been in the spheno-orbital location. We present a series of select purely sphenoid wing and middle fossa meningiomas removed through eLTOA. The objective here was to describe the selection criteria and results of eLTOA for a subset of sphenoid wing and middle fossa meningiomas. METHODS: This is a retrospective study based on a prospectively maintained database of consecutive cases of eLTOA operated on at our institution by the lead author. The cohort's clinical and radiographic characteristics and outcome are presented. RESULTS: Five patients underwent eLTOA to remove 3 sphenoid wing and 2 middle fossa meningiomas. The mean tumor volume was 11.9 cm 3 . Gross total resection was achieved in all cases. There were no intraoperative complications. Postoperatively, there was one case of subretinal hemorrhage, which was corrected by open vitrectomy repair, and one case of cerebrospinal fluid leak, which resolved with lumbar drainage. Three patients presented with visual impairment, 1 improved, 1 remained stable, and 1 worsened, but returned to stable after vitrectomy repair. All patients have been free of disease at a median follow-up of 8.9 months. CONCLUSION: eLTOA provides a direct minimal access corridor to certain well-selected sphenoid wing and middle fossa meningiomas. eLTOA minimizes brain retraction and provides a high rate of gross total resection. Meningiomas appropriately selected based on size, type, and location of dural attachment, and the eLTOA is a safe, rapid, and highly effective procedure with acceptable morbidity.

Fourth ventricular subarachnoid stent for Chiari malformation type I-associated persistent syringomyelia.

OBJECTIVE: Syringomyelia (syrinx) associated with Chiari malformation type I (CM-I) is commonly managed with posterior fossa decompression, which can lead to resolution in most cases. A persistent syrinx postdecompression is therefore uncommon and challenging to address. In the setting of radiographically adequate decompression with persistent syrinx, the authors prefer placing fourth ventricular subarachnoid stents that span the craniocervical junction particularly when intraoperative observation reveals arachnoid plane scarring. The objective of this study was to evaluate the safety and efficacy of a fourth ventricle stent for CM-I-associated persistent syringomyelia, assess dynamic changes in syrinx dimensions, and report stent-reduction durability, clinical outcomes, and procedure-associated complications. METHODS: The authors performed a single-institution, retrospective review of patients who underwent fourth ventricular subarachnoid stent placement for persistent CM-I-associated syringomyelia following a prior posterior fossa decompression. The authors' institutional Chiari database contains 600 cases with 149 decompressions for CM-I-associated syringomyelia, of which 13 met criteria for inclusion. Data on patient demographics, clinical presentation and outcomes, and MRI findings were collected. The maximal syrinx diameter was estimated by calculating the area of an elliptical cross-section in the largest axial plane from preoperative, immediately postoperative, and late postoperative T2-weighted MR images. RESULTS: All 13 patients experienced a significant decrease in mean syrinx area from the preoperative to the late postoperative MRI (mean syrinx diameter 114.1 ± 81.8 mm2 vs 24.5 ± 23.8 mm2, p < 0.001). The mean time until late postoperative MRI was 19.7 months (range 2.0-70.7 months). The syrinx area reduced on average by 75.0% ± 23.9% at the time of the last postoperative scan. Syrinx resolution was variable, with 4 patients (30.8%) achieving near-complete resolution (> 90%, grade III reduction), 7 patients (50%) having 50%-90% reduction (grade II), and 2 patients (14.3%) having < 50% decrease (grade I). One patient experienced catheter migration into the left brachium pontis with an associated cyst at the tip of the catheter that decreased in size on follow-up imaging. CONCLUSIONS: Placement of fourth ventricular subarachnoid stents spanning the craniocervical junction in patients with persistent CM-I-associated syringomyelia after posterior fossa decompression is a safe therapeutic option and significantly reduced the mean syrinx area, with a greater reductive effect seen over longer follow-up periods.

Intraoperative occipital to C2 angle and external acoustic meatus-to-axis angular measurements for optimizing alignment during posterior fossa decompression and occipitocervical fusion for complex Chiari malformation.

Background: Excess flexion or extension during occipitocervical fusion (OCF) can lead to postoperative complications, such as dysphagia, respiratory problems, line of sight issues, and neck pain, but posterior fossa decompression (PFD) and OCF require different positions that require intraoperative manipulation. Objective: The objective of this study was to describe quantitative fluoroscopic morphometrics in Chiari malformation (CM) patients with symptoms of craniocervical instability (CCI) and demonstrate the intraoperative application of these measurements to achieve neutral craniocervical alignment while leveraging a single axis of motion with the Mayfield head clamp locking mechanism. Methods: A retrospective cohort study of patients with CM 1 and 1.5 and features of CCI who underwent PFD and OCF at a single-center institution from March 2015 to October 2020 was performed. Patient demographics, preoperative presentation, radiographic morphometrics, operative details, complications, and clinical outcomes were analyzed. Results: A total of 39 patients met the inclusion criteria, of which 37 patients (94.9%) did not require additional revision surgery after PFD and OCF. In this nonrevision cohort, preoperative to postoperative occipital to C2 angle (O-C2a) (13.5° ± 10.4° vs. 17.5° ± 10.1°, P = 0.047) and narrowest oropharyngeal airway space (nPAS) (10.9 ± 3.4 mm vs. 13.1 ± 4.8 mm, P = 0.007) increased significantly. These measurements were decreased in the two patients who required revision surgery due to postoperative dysphagia (mean difference - 16.6°° in O C2a and 12.8°° in occipital and external acoustic meatus to axis angle). Based on these results, these fluoroscopic morphometrics are intraoperatively assessed, utilizing a locking Mayfield head clamp repositioning maneuver to optimize craniocervical alignment prior to rod placement from the occipital plate to cervical screws. Conclusion: Establishing a preoperative baseline of reliable fluoroscopic morphometrics can guide surgeons intraoperatively in appropriate patient realignment during combined PFD and OCF, and may prevent postoperative complications.

Myofascial Flap Closure Decreases Complications in Complex Surgery of the Craniocervical Junction in Ehlers-Danlos Patients.

INTRODUCTION: Patients with Ehlers-Danlos syndrome (EDS) are at elevated risk for soft tissue complications when undergoing decompression with or without fusion of the craniocervical junction. We have previously shown that muscle flap closure can decrease reoperative rates. This study investigated whether myofascial flap closure improved clinical outcomes after simple or complex surgery of the craniocervical junction in EDS patients specifically. METHODS: We performed a retrospective chart review of EDS patients who had undergone surgery for Chiari malformation at the Weill Cornell Medical Center between 2013 and 2020. Postoperative complications were recorded, including infection, wound dehiscence, seroma, hematoma, hardware removal, cerebrospinal fluid (CSF) leak, reoperation, and pseudomeningocele. Patients were stratified by type of closure and type of surgery. Fisher exact test was used for statistical comparison. RESULTS: Between 2013 and 2020, 62 EDS patients who had surgery of the cervicocranial junction were reviewed. Of these, 31 patients had complex surgery with myofascial flap closure and 22 had simple surgery with traditional closure. The mean age at the time of surgery was 21.3 years. There were no significant differences in wound complications or reoperation rates between the simple surgery and complex surgery groups. In addition, there were no significant differences in complications between complex surgery with flap closure and simple surgery with traditional closure. Our CSF cutaneous fistula rate was 0%, considerably lower than rates reported in the literature, and, in one case, a patient developed a postoperative pseudomeningocele secondary to a dural leak, but the myofascial flap closure prevented its progression. CONCLUSIONS: Patients with EDS undergoing surgery of the cervicocranial junction may benefit from myofascial flap closure. Flap closure reduced complications after complex surgery of the craniocervical junction to the level of simple surgery. Our CSF leak rate was exceptionally low and only one patient experienced pseudomeningocele. Myofascial flaps are safe to perform in the EDS cohort and prevented CSF cutaneous fistula formation.

Association between city-wide lockdown and COVID-19 hospitalization rates in multigenerational households in New York City.

BACKGROUND: City-wide lockdowns and school closures have demonstrably impacted COVID-19 transmission. However, simulation studies have suggested an increased risk of COVID-19 related morbidity for older individuals inoculated by house-bound children. This study examines whether the March 2020 lockdown in New York City (NYC) was associated with higher COVID-19 hospitalization rates in neighborhoods with larger proportions of multigenerational households. METHODS: We obtained daily age-segmented COVID-19 hospitalization counts in each of 166 ZIP code tabulation areas (ZCTAs) in NYC. Using Bayesian Poisson regression models that account for spatiotemporal dependencies between ZCTAs, as well as socioeconomic risk factors, we conducted a difference-in-differences study amongst ZCTA-level hospitalization rates from February 23 to May 2, 2020. We compared ZCTAs in the lowest quartile of multigenerational housing to other quartiles before and after the lockdown. FINDINGS: Among individuals over 55 years, the lockdown was associated with higher COVID-19 hospitalization rates in ZCTAs with more multigenerational households. The greatest difference occurred three weeks after lockdown: Q2 vs. Q1: 54% increase (95% Bayesian credible intervals: 22-96%); Q3 vs. Q1: 48% (17-89%); Q4 vs. Q1: 66% (30-211%). After accounting for pandemic-related population shifts, a significant difference was observed only in Q4 ZCTAs: 37% (7-76%). INTERPRETATION: By increasing house-bound mixing across older and younger age groups, city-wide lockdown mandates imposed during the growth of COVID-19 cases may have inadvertently, but transiently, contributed to increased transmission in multigenerational households.

Transitioning preclinical students into clerkships amidst curricular disruptions from the COVID-19 pandemic.

The COVID-19 pandemic resulted in significant disruptions to medical education. The patient care space was unavailable as a learning environment, which compounded the complexity of preparing students for clerkships with a traditional transition to clerkship (TTC) curriculum. We developed a multimodal, structured approach to re-introduce students to the clinical space prior to the start of clerkships. 105 second year medical students completed a 4-week clinical enhancement course. A modified Delphi method was used to select core topics, which were then anchored to key Entrustable Professional Activities (EPAs). Students participated in 9 virtual problem-based cases, workshops and multiple supervised patient encounters. Students were surveyed before, during, and after the course; responses were compared with paired t-tests. 25.9% rated the course as excellent, 44.2% as very good, and 19.5% as good. Compared to baseline, self-perceived efficacy grew significantly (P < 0.05) across all EPAs. Improvements in key competencies were sustained when students were surveyed 2 weeks into their first clerkship. This was a well-received, novel course, focused on helping students transition back into the clinical space through a multimodal teaching approach. This framework may be used by other institutions seeking to restructure their TTC initiatives.

Revision Chiari Surgery in Young Children: Predictors and Outcomes.

INTRODUCTION: Children aged 0-6 years with Chiari malformation (CM) often present with atypical symptoms and require revision surgery more often than older children. We studied characteristics and outcomes of CM patients in this age-group who underwent one or more revision surgeries to assess how often revision surgery is necessary and successful in this age-group. METHODS: We retrospectively reviewed patients who were diagnosed with CM 1 or CM 1.5 and surgically treated with posterior fossa decompression (PFD) with or without duraplasty before their 7th birthday. Basic demographics, preoperative presentation, operative details, and postoperative outcomes were analyzed. RESULTS: Forty patients (mean age 3.2 ± 1.7 years, 35% female) were reviewed. The most common presenting symptoms were headache, dysphagia, and respiratory problems. Eight patients required one or more revision surgeries 11.6 ± 7.6 months on average after their initial surgery. Comparing the revision and no revision groups, dysautonomia was significantly more common prior to initial surgery in the children requiring revision (37.5 vs. 3.1%, p = 0.02). The revision group also trended toward more dysphagia (75.0 vs. 46.9%, p = 0.24) and respiratory problems (75.0 vs. 40.6%, p = 0.12). The most frequent reasons for reoperation were symptom recurrence (6/8), residual posterior fossa compression (3/8), significant scar tissue formation (2/8), ventral brainstem compression (1/8), and suspected craniocervical instability (1/8). Of the 8 children undergoing reoperation, surgery achieved symptom resolution or improvement in 5, while 3 had unchanged symptoms. Two patients underwent a third surgery, after which 1 showed improvement and the other did not. This last patient showed short-term improvement after a fourth surgery but had symptom recurrence 12 months later. DISCUSSION/CONCLUSION: Oropharyngeal and respiratory problems are particularly common in children aged 0-6 years with CM. Presentation with dysautonomia or other signs of brainstem compression will often predict an additional surgery will be needed after an initial PFD. Symptom recurrence is the most frequent reason for reoperation, and revision surgeries lead to improved clinical outcomes in the majority but not all of these young patients. Surgery in very young children is successful, but reoperation should be integrated into an up-front discussion algorithm particularly in children with severe symptoms.

Ventral Tonsillar Herniation Predicts Headaches in Adults With Chiari Malformation.

BACKGROUND: Radiographic characterization of Chiari malformation (CM) has historically focused on caudal tonsillar herniation (CH) below the foramen magnum. Previously, we published evidence linking ventral tonsillar herniation (VH) and medullary symptoms in very young children. We sought to extend that investigation by studying the radiographic and clinical significance of VH in adults diagnosed with CM. METHODS: We retrospectively reviewed adults with cerebellar ectopia who underwent posterior fossa decompression with or without duraplasty (PFD/D) at our institution. VH was defined as tonsils crossing a line bisecting the caudal medulla at the level of the foramen magnum on axial MRI. Degree of VH was measured as distance between this bisecting line and the ventral tip of the herniated tonsil. Dorsal brainstem compression was qualitatively determined by assessing for obliteration of CSF space between the dorsal brainstem and the tonsils. RESULTS: Out of 89 cases reviewed, 54 had some degree of VH. Compared with those without VH, the VH group was significantly older in age and more likely to also present with dorsal brainstem compression and headaches. No correlation was observed between degrees of CH and VH in the VH group. The degree of VH significantly decreased 3 months after PFD/D. CONCLUSIONS: VH is relatively common in CM patients and might be an important independent radiographic metric to evaluate and consider as part of the decision-making process, especially in those presenting with Chiari-like symptomatology referable to the medulla but who do not meet the traditional criteria of cerebellar ectopia greater than 5 mm.

Association between overcrowded households, multigenerational households, and COVID-19: a cohort study.

INTRODUCTION: The role of overcrowded and multigenerational households as a risk factor for COVID-19 remains unmeasured. The objective of this study is to examine and quantify the association between overcrowded and multigenerational households, and COVID-19 in New York City (NYC). METHODS: We conducted a Bayesian ecological time series analysis at the ZIP Code Tabulation Area (ZCTA) level in NYC to assess whether ZCTAs with higher proportions of overcrowded (defined as proportion of estimated number of housing units with more than one occupant per room) and multigenerational households (defined as the estimated percentage of residences occupied by a grandparent and a grandchild less than 18 years of age) were independently associated with higher suspected COVID-19 case rates (from NYC Department of Health Syndromic Surveillance data for March 1 to 30, 2020). Our main measure was adjusted incidence rate ratio (IRR) of suspected COVID-19 cases per 10,000 population. Our final model controlled for ZCTA-level sociodemographic factors (median income, poverty status, White race, essential workers), prevalence of clinical conditions related to COVID-19 severity (obesity, hypertension, coronary heart disease, diabetes, asthma, smoking status, and chronic obstructive pulmonary disease), and spatial clustering. RESULTS: 39,923 suspected COVID-19 cases presented to emergency departments across 173 ZCTAs in NYC. Adjusted COVID-19 case rates increased by 67% (IRR 1.67, 95% CI = 1.12, 2.52) in ZCTAs in quartile four (versus one) for percent overcrowdedness and increased by 77% (IRR 1.77, 95% CI = 1.11, 2.79) in quartile four (versus one) for percent living in multigenerational housing. Interaction between both exposures was not significant (ß interaction = 0.99, 95% CI: 0.99-1.00). CONCLUSIONS: Over-crowdedness and multigenerational housing are independent risk factors for suspected COVID-19. In the early phase of surge in COVID cases, social distancing measures that increase house-bound populations may inadvertently but temporarily increase SARS-CoV-2 transmission risk and COVID-19 disease in these populations.

Neurosurgery in COVID-19 Ground Zero: The Weill Cornell Medicine Experience.

The mobilization of subspecialty departments in reaction to the unique demands of the onset of the coronavirus disease 2019 (COVID-19) pandemic in New York City was swift and left little time for reflection and commemoration. The early days of the pandemic brought unprecedented stressors on the medical system that necessitated a restructuring of hospitals, reallocation of health care workers, and a shift in care and education paradigms to meet patient care demands and public health needs. As the number of cases, intensive care unit patients, and deaths skyrocketed in New York City, many struggled with a somewhat paradoxical difficulty in perceiving the human value of what these numbers mean. Easily lost in the statistics are the stories and experiences of the physicians and trainees who were counted on to halt their own clinical practices and adapt their skillsets to tackle the pandemic. In this article, we present 10 brief narratives from the student members of the Neurosurgery Publication Group at Weill Cornell Medical College and members of the Weill Cornell Medicine Neurological Surgery Residency Program and Department of Neurological Surgery faculty. Reflecting on these individual experiences gives us an opportunity to simultaneously contribute to a history of New York City's reaction to COVID-19 and commemorate the individuals who were impacted by or succumbed to this disease.

Predicting clinical outcomes using morphometric changes in adults with complex Chiari malformation undergoing occipitocervical fusion with or without ventral decompression: patient series.

BACKGROUND: The authors assessed the connection between clinical outcomes and morphometrics in patients with complex Chiari malformation (CM) who have undergone posterior fossa decompression (PFD) and subsequent occipitocervical fusion (OCF) with or without ventral decompression (VD). OBSERVATIONS: The authors retrospectively reviewed 33 patients with CM aged over 21 years who underwent PFD and OCF with or without endoscopic endonasal odontoidectomy at the authors' institution (21 OCF only and 12 OCF + VD). Clivoaxial angle (CXA), pB-C2 (perpendicular line to the line between the basion and C2), atlantodental interval (ADI), basion-dens interval (BDI), basion-axial interval (BAI), and C1 canal diameter were measured on preoperative and approximately 3-month postoperative computed tomography or magnetic resonance imaging scans. Common symptoms included headache, paresthesia, and bulbar symptoms. Clinical improvement after surgery was observed in 78.8% of patients. CXA, ADI, and BDI all significantly increased after surgery, whereas pB-C2 and BAI significantly decreased. OCF + VD had a significantly more acute CXA and longer pB-C2 preoperatively than OCF only. Patients who clinically improved postoperatively showed the same significant morphometric changes, but those who did not improve showed no significant morphometric changes. LESSONS: Patients showing improvement had greater corrections in skull base morphometrics than those who did not. Although there are various mutually nonexclusive reasons why certain patients do not improve after surgery, smaller degrees of morphometric correction could play a role.

Increase in clivo-axial angle is associated with clinical improvement in children undergoing occipitocervical fusion for complex Chiari malformation: patient series.

BACKGROUND: The authors analyzed the pre- and postoperative morphometric properties of pediatric patients with complex Chiari malformation undergoing occipitocervical fusion (OCF) to assess clinical outcomes and morphometric properties that might influence postoperative outcomes. OBSERVATIONS: The authors retrospectively reviewed 35 patients younger than 22 years with Chiari malformation who underwent posterior fossa decompression and OCF with or without endoscopic endonasal odontoidectomy at their institution (13 with and 22 without odontoidectomy). Clivo-axial angle (CXA), pB-C2, atlantodental interval, basion-dens interval, basion-axial interval, and canal diameter at the level of C1 were measured on preoperative and approximately 3-month postoperative computed tomography or magnetic resonance imaging. The authors further stratified the patient cohort into three age groups and compared the three cohorts. The most common presenting symptoms were headache, neck/shoulder pain, and dysphagia; 80% of the cohort had improved clinical outcomes. CXA increased significantly after surgery. When stratified into those who showed postoperative improvement and those who did not, only the former showed a significant increase in CXA. After age stratification, the significant changes in CXA were observed in the 7- to 13-year-old and 14- to 21-year-old cohorts. LESSONS: CXA may be the most important morphometric predictor of clinical outcomes after OCF in pediatric patients with complex Chiari malformation.

Medical Student Concerns Relating to Neurosurgery Education During COVID-19.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has created significant obstacles within medical education. For medical students interested in pursuing neurosurgery as a specialty, the educational policies surrounding COVID-19 have resulted in unique challenges. The present study used a nationwide survey to identify the concerns of medical students interested in pursuing neurosurgery during the COVID-19 pandemic. METHODS: Students who had previously registered for medical student neurosurgery training camps were sent an online Qualtrics survey requesting them to assess how the COVID-19 pandemic was affecting their neurosurgical education. The Pearson χ2 test and post hoc pairwise Fisher exact test were used for analysis of categorical variables, and the 2-tailed paired Student t test was used for continuous variables. RESULTS: The survey was distributed to 852 medical students, with 127 analyzed responses. Concerns regarding conferences and networking opportunities (63%), clinical experience (59%), and board examination scores (42%) were most frequently cited. Of the third-year medical students, 76% reported ≥1 cancelled or postponed neurosurgery rotation. On average, students were more likely to take 1 year off from medical school after than before the start of the COVID-19 pandemic, measured from 0 to 100 (25.3 ± 36.0 vs. 39.5 ± 37.5; P = 0.004). Virtual mentorship pairing was the highest rated educational intervention suggested by first- and second-year medical students. The third- and fourth-year medical students had cited virtual surgical skills workshops most frequently. CONCLUSIONS: The results from the present nationwide survey have highlighted the concerns of medical students regarding their neurosurgery education during the COVID-19 pandemic. With these findings, neurosurgery organizations can consider targeted plans for students of each year to continue their education and development.