Impact of the first wave of the SARS-CoV-2 pandemic on the outcome of neurosurgical patients: a nationwide study in Spain

ObjectiveTo assess the effect of the first wave of the SARS-CoV-2 pandemic on the outcome of neurosurgical patients in Spain.SettingsThe initial flood of COVID-19 patients overwhelmed an unprepared healthcare system. Different measures were taken to deal with this overburden. The effect of these measures on neurosurgical patients, as well as the effect of COVID-19 itself, has not been thoroughly studied.ParticipantsThis was a multicentre, nationwide, observational retrospective study of patients who underwent any neurosurgical operation from March to July 2020.InterventionsAn exploratory factorial analysis was performed to select the most relevant variables of the sample.Primary and secondary outcome measuresUnivariate and multivariate analyses were performed to identify independent predictors of mortality and postoperative SARS-CoV-2 infection.ResultsSixteen hospitals registered 1677 operated patients. The overall mortality was 6.4%, and 2.9% (44 patients) suffered a perioperative SARS-CoV-2 infection. Of those infections, 24 were diagnosed postoperatively. Age (OR 1.05), perioperative SARS-CoV-2 infection (OR 4.7), community COVID-19 incidence (cases/105 people/week) (OR 1.006), postoperative neurological worsening (OR 5.9), postoperative need for airway support (OR 5.38), ASA grade ≥3 (OR 2.5) and preoperative GCS 3–8 (OR 2.82) were independently associated with mortality. For SARS-CoV-2 postoperative infection, screening swab test <72 hours preoperatively (OR 0.76), community COVID-19 incidence (cases/105 people/week) (OR 1.011), preoperative cognitive impairment (OR 2.784), postoperative sepsis (OR 3.807) and an absence of postoperative complications (OR 0.188) were independently associated.ConclusionsPerioperative SARS-CoV-2 infection in neurosurgical patients was associated with an increase in mortality by almost fivefold. Community COVID-19 incidence (cases/105 people/week) was a statistically independent predictor of mortality.Trial registration numberCEIM 20/217.

Intraoperative Resting-State Functional Connectivity Based on RGB Imaging

RGB optical imaging is a marker-free, contactless, and non-invasive technique that is able to monitor hemodynamic brain response following neuronal activation using task-based and resting-state procedures. Magnetic resonance imaging (fMRI) and functional near infra-red spectroscopy (fNIRS) resting-state procedures cannot be used intraoperatively but RGB imaging provides an ideal solution to identify resting-state networks during a neurosurgical operation. We applied resting-state methodologies to intraoperative RGB imaging and evaluated their ability to identify resting-state networks. We adapted two resting-state methodologies from fMRI for the identification of resting-state networks using intraoperative RGB imaging. Measurements were performed in 3 patients who underwent resection of lesions adjacent to motor sites. The resting-state networks were compared to the identifications provided by RGB task-based imaging and electrical brain stimulation. Intraoperative RGB resting-state networks corresponded to RGB task-based imaging (DICE:0.55±0.29). Resting state procedures showed a strong correspondence between them (DICE:0.66±0.11) and with electrical brain stimulation. RGB imaging is a relevant technique for intraoperative resting-state networks identification. Intraoperative resting-state imaging has several advantages compared to functional task-based analyses: data acquisition is shorter, less complex, and less demanding for the patients, especially for those unable to perform the tasks.

P.211 Characterizing and comparing brain injury associated with traditional self-retracting brain retractors with novel tubular retractors

Background: Tubular retractors are FDA approved and in the Neurosurgical marketplace, but adaptation has been hampered by lack of evidence showing superiority over traditional retractors when performing subcortical surgery. This study examines brain injury associated with traditional brain retractors versus tubular retractors. Methods: Nine porcine models underwent a simulated neurosurgical operation. Retractors were inserted for four hours after which the porcine model was euthanized. The en-bloc extracted porcine brain was fixed in 10% formalin, paraffin embedded, sectioned at 4 um and stained with hematoxylin and eosin (H&E) using standard laboratory protocols. Computer algorithms were generated to calculate areas of cerebral edema and hemorrhage adjacent to retractor surfaces. Results: Using a two-tailed t-test with a significance level of 0.05, traditional brain retractors were associated with statistically significant greater areas of cerebral edema when compared to tubular retractors (17.36 um2 vs. 12.42 um2; p = 0.0038). There was no statistically significant difference in mean areas of hemorrhage between traditional brain retractors and tubular retractors (3.43 um2 vs 3.60 um2; p = 0.8297). Conclusions: Tubular retractors are associated with significantly less edema in surrounding brain than traditional retractors. On histopathological merits, this study supports the application of tubular retractors over traditional retractors.

1503 Review of Electronic Theatre Coding System & Documentation of Neurosurgical Activity

Introduction It was noticed that the current electronic theatre coding system was limited in its reflection of departmental theatre activity and discrepancies in discharge letters compared to the actual operations performed. To prevent this from recurring, a standardised neurosurgical operation note was developed, and an audit of the electronic coding system was undertaken to see if the correct operation matched that of the code listed. Method A 6-month retrospective analysis from March to September 2020 was completed using the electronic theatre coding system, patients’ electronic records and the patient handover list. Results 232 operations performed and only 10.3% of procedures were correctly coded by the current coding system. 11 operations were not on the theatre system although performed in theatres. The current system only coded for 82 procedures and did not show the full range of operations. There was wide variety of operation notes and only 185 operation notes were found on the patients’ electronic record. Frequently the procedure was not clearly identified so juniors relied on the inaccurate electronic code on the theatre list for the patients’ operation hence explaining the problem identified in discharge letters. Conclusions A new coding list for the electronic theatre system was created with 228 procedures divided into correct subcategories. A standardised template for operation notes was also developed and implemented so that full neurosurgical departmental activity is reflected, and accurate discharge letters are completed so that complete data collection can be done for audit purposes.

Reactivation of COVID-19 in a neurosurgical patient with early neuropsychiatric presentation. Does seroconversion mean immunity?

Background: In the aftermath of COVID-19 outbreak, there is a strong need to find strategies to monitor SARSCoV-2 transmission. While the application of screening techniques plays a major role to this end, there is evidence challenging the real significance of seroconversion. We reported a case of COVID-19 reactivation associated with a neurosurgical operation with early neuropsychiatric involvement presumably promoted by olfactory and gustatory impairment in the first infection. Case Descriptio: A 57-year-old man was referred for a 2-month history of progressive development of imbalance, dizziness, and vomiting. Magnetic resonance imaging showed two bilateral hemispheric cerebellar lesions. In line with our triage protocol, the patient underwent a nasopharyngeal swab for RNA of SARS-CoV-2 detection, which resulted positive. Of note, the patient had reported in the previous month hyposmia and hypogeusia. After a period of 14 days, three new swabs were performed with negative results, leading the way to surgery. In the early post-operative period, the patient manifested acute onset of psychotic symptoms with hyperactive delirium, followed by fever and acute respiratory failure. A chest computed tomography revealed a specific pattern of ground-glass opacities in the lower lobes bilaterally, suggesting a viral pneumonia. Serological tests demonstrated the seroconversion and a new nasopharyngeal swab confirmed SARS-CoV-2 infection. Conclusion: Our report highlights the importance of comprehensive screening assessments in sensitive cases highly susceptible to COVID-19 recurrence.

SURG-21. ENDO- AND EXOSCOPIC SURGERY FOR PEDIATRIC NEUROSURGICAL OPERATION

INTRODUCTION Recently endo- and exoscopic surgeries have been gradually performed in neurosurgery. To improve the accuracy and safety of our endoscopic procedures, we are currently trialing 4K or 8K systems. Here we report our experience of endo- and exoscopic procedures for pediatric neurosurgery. METHODS We retrospectively identified 22 patients (15 males, 7 females; mean age, 9.2 years) who underwent surgery for sellar lesions and intraventricular or intraparenchymal lesions with an endo- or exoscopic procedure at our institute between 2010 and 2020. We used a full HD endoscope system (Storz) and an organic electroluminescence (EL) monitor (Sony), and a 4K system (Sony and Olympus). VITOM 3D (Storz) was used as the exoscope. Videoscope (Olympus) was used as a flexible scope for intraventricular tumors. RESULTS We performed surgical procedures as 11 biopsies, 6 third ventriculostomies, 5 resections, and 3 fenestrations. The full HD system with organic EL monitor presented high color contrast. We could easily distinguish between tumor microstructure and the normal structure with the 4K system comparing to full HD. Moreover, electronic zoom function enabled us to discriminate tumor boundaries without having to move the endoscope closer. As a result, we could delineate the surgical working space. VITOM 3D was simple to sharpen the focus on the wider surgical field, similar to the application of an operating microscope. CONCLUSION In pediatric neurosurgery, an endo- or exoscope enables clear visual recognition of a boundary between tumor and normal area.