Herniation World Federation of Neurosurgical Societies Scale Improves Prediction of Outcome in Patients With Poor-Grade Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Favorable outcomes are seen in up to 50% of patients with World Federation of Neurosurgical Societies (WFNS) grade V aneurysmal subarachnoid hemorrhage. Therefore, the usefulness of the current WFNS grading system for identifying the worst scenarios for clinical studies and for making treatment decisions is limited. We previously modified the WFNS scale by requiring positive signs of brain stem dysfunction to assign grade V. This study aimed to validate the new herniation WFNS grading system in an independent prospective cohort. METHODS: We conducted an international prospective multicentre study in poor-grade aneurysmal subarachnoid hemorrhage patients comparing the WFNS classification with a modified version-the herniation WFNS scale (hWFNS). Here, only patients who showed positive signs of brain stem dysfunction (posturing, anisocoric, or bilateral dilated pupils) were assigned hWFNS grade V. Outcome was assessed by modified Rankin Scale score 6 months after hemorrhage. The primary end point was the difference in specificity of the WFNS and hWFNS grading with respect to poor outcomes (modified Rankin Scale score 4-6). RESULTS: Of the 250 patients included, 237 reached the primary end point. Comparing the WFNS and hWFNS scale after neurological resuscitation, the specificity to predict poor outcome increased from 0.19 (WFNS) to 0.93 (hWFNS) (McNemar, P<0.001) whereas the sensitivity decreased from 0.88 to 0.37 (P<0.001), and the positive predictive value from 61.9 to 88.3 (weighted generalized score statistic, P<0.001). For mortality, the specificity increased from 0.19 to 0.93 (McNemar, P<0.001), and the positive predictive value from 52.5 to 86.7 (weighted generalized score statistic, P<0.001). CONCLUSIONS: The identification of objective positive signs of brain stem dysfunction significantly improves the specificity and positive predictive value with respect to poor outcome in grade V patients. Therefore, a simple modification-presence of brain stem signs is required for grade V-should be added to the WFNS classification. REGISTRATION: URL: https://clinicaltrials.gov; Unique identifier: NCT02304328.

Association of the COVID-19 outbreak with acute stroke care in Switzerland.

BACKGROUND AND PURPOSE: In Switzerland, the COVID-19 incidence during the first pandemic wave was high. Our aim was to assess the association of the outbreak with acute stroke care in Switzerland in spring 2020. METHODS: This was a retrospective analysis based on the Swiss Stroke Registry, which includes consecutive patients with acute cerebrovascular events admitted to Swiss Stroke Units and Stroke Centers. A linear model was fitted to the weekly admission from 2018 and 2019 and was used to quantify deviations from the expected weekly admissions from 13 March to 26 April 2020 (the "lockdown period"). Characteristics and 3-month outcome of patients admitted during the lockdown period were compared with patients admitted during the same calendar period of 2018 and 2019. RESULTS: In all, 28,310 patients admitted between 1 January 2018 and 26 April 2020 were included. Of these, 4491 (15.9%) were admitted in the periods March 13-April 26 of the years 2018-2020. During the lockdown in 2020, the weekly admissions dropped by up to 22% compared to rates expected from 2018 and 2019. During three consecutive weeks, weekly admissions fell below the 5% quantile (likelihood 0.38%). The proportion of intracerebral hemorrhage amongst all registered admissions increased from 7.1% to 9.3% (p = 0.006), and numerically less severe strokes were observed (median National Institutes of Health Stroke Scale from 3 to 2, p = 0.07). CONCLUSIONS: Admissions and clinical severity of acute cerebrovascular events decreased substantially during the lockdown in Switzerland. Delivery and quality of acute stroke care were maintained.

Patterns of Neointima Formation After Coil or Stent Treatment in a Rat Saccular Sidewall Aneurysm Model.

BACKGROUND AND PURPOSE: Endovascular aneurysm treatment relies on a biological process, including cell migration for thrombus organization and growth of a neointima. To better understand aneurysm healing, our study explores the origin of neointima-forming and thrombus-organizing cells in a rat saccular sidewall aneurysm model. METHODS: Saccular aneurysms were transplanted onto the abdominal aorta of male Lewis rats and endovascularly treated with coils (n=28) or stents (n=26). In 34 cases, GFP+ (green fluorescent protein)-expressing vital aneurysms were sutured on wild-type rats, and in 23 cases, decellularized wild-type aneurysms were sutured on GFP+ rats. Follow-up at 3, 7, 14, 21, and 28 days evaluated aneurysms by fluorescence angiography, macroscopic inspection, and microscopy for healing and inflammation status. Furthermore, the origin of cells was tracked with fluorescence histology. RESULTS: In animals with successful functional healing, histological studies showed a gradually advancing thrombus organization over time characterized by progressively growing neointima from the periphery of the aneurysm toward the center. Cell counts revealed similar distributions of GFP+ cells for coil or stent treatment in the aneurysm wall (54.4% versus 48.7%) and inside the thrombus (20.5% versus 20.2%) but significantly more GFP+ cells in the neointima of coiled (27.2 %) than stented aneurysms (10.4%; P=0.008). CONCLUSIONS: Neointima formation and thrombus organization are concurrent processes during aneurysm healing. Thrombus-organizing cells originate predominantly in the parent artery. Neointima formation relies more on cell migration from the aneurysm wall in coiled aneurysms but receives greater contributions from cells originating in the parent artery in stent-treated aneurysms. Cell migration, which allows for a continuous endothelial lining along the parent artery's lumen, may be a prerequisite for complete aneurysm healing after endovascular therapy. In terms of translation into clinical practice, these findings may explain the variability in achieving complete aneurysm healing after coil treatment and the improved healing rate in stent-assisted coiling.

Incidence and Outcome of Aneurysmal Subarachnoid Hemorrhage: The Swiss Study on Subarachnoid Hemorrhage (Swiss SOS).

BACKGROUND AND PURPOSE: The purpose of this study was to assess nationwide incidence and outcomes of aneurysmal subarachnoid hemorrhage (aSAH). The Swiss SOS (Swiss Study on Subarachnoid Hemorrhage) was established in 2008 and offers the unique opportunity to provide this data from the point of care on a nationwide level. METHODS: All patients with confirmed aneurysmal subarachnoid hemorrhage admitted between January 1, 2009 and December 31, 2014, within Switzerland were recorded in a prospective registry. Incidence rates were calculated based on time-matched population data. Admission parameters and outcomes at discharge and at 1 year were recorded. RESULTS: We recorded data of 1787 consecutive patients. The incidence of aneurysmal subarachnoid hemorrhage in Switzerland was 3.7 per 100 000 persons/y. The number of female patients was 1170 (65.5%). With a follow-up rate of 91.3% at 1 year, 1042 patients (58.8%) led an independent life according to the modified Rankin Scale (0-2). About 1 in 10 patients survived in a dependent state (modified Rankin Scale, 3-5; n=185; 10.4%). Case fatality was 20.1% (n=356) at discharge and 22.1% (n=391) after 1 year. CONCLUSIONS: The current incidence of aneurysmal subarachnoid hemorrhage in Switzerland is lower than expected and an indication of a global trend toward decreasing admissions for ruptured intracranial aneurysms. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03245866.

Intraoperative findings, complications, and short-term results after lumbar microdiscectomy with or without implantation of annular closure device.

BACKGROUND: Standard microscopic lumbar discectomy (MLD) is a short operation with minimal blood loss, and a low rate of peri- and intraoperative complications. The objective of this study was to evaluate intraoperative findings, complications, and early postoperative neurological outcome (< 105 days) in patients undergoing MLD with or without implantation of an annular closure device (ACD). METHODS: This study is based on data analysis of a post-marketing, prospective, multicenter RCT in Europe including patients undergoing standard MLD with or without implantation of an ACD (Barricaid®, Intrinsic Therapeutics, Inc., Woburn, MA). Enrollment of 554 patients in 21 centers in Europe (Germany, Switzerland, Austria, Belgium, The Netherlands, and France) started in 2010 and was completed in October 2014, with 276 patients randomized to the ACD group and 278 to the control group. RESULTS: Mean operation time was 70 min in the ACD group and 52 min in the control group (p < 0.0001). Intraoperative fluoroscopy time was 24 s in the ACD group and 7 s in the control group (p < 0.0001). Average blood loss was 94.2 ml in the ACD group and 64.7 ml in the control group (p = 0.0001). Serious device- or procedure-related adverse events occurred in 3.7% (10/272) of the ACD group and 7.9% (22/278) of the control group. Dural injuries occurred in 13 (4.8%) patients in the ACD group and 7 (2.5%) in the control group. There was one device-related nerve root injury resulting in a nerve root amputation. Surgical complications included 3 hematomas in the ACD group and 4 in the control group; 3 infections occurred in both groups. Device migrations were documented in 3 patients in the ACD group. Patients in the ACD group (n = 7, 2.6%) underwent fewer reoperations compared with that in the control group (n = 16, 5.8%, OR = 2.3 (0.9-5.7)). Mean VAS leg pain at 3 months was 11.9 in the ACD and 15.1 in the control group, respectively. CONCLUSION: Short-term outcome after MLD with or without implantation of ACD was similar in both groups. Patients included in the ACD group underwent fewer reoperations in the first 3 months after surgery. Nevertheless, longer operation time, higher amount of blood loss, and risk of nerve root lesion during device implantation should be considered additional risks in patients undergoing ACD implantation after MLD.

The Shape grading system: a classification for growth patterns of pituitary adenomas.

BACKGROUND: Long-term tumor control of pituitary adenomas may be achieved by gross total resection (GTR). Factors, which influence the extent of resection, are invasiveness, tumor size, and possibly tumor shape. Nevertheless, the latter factor has not been assessed so far and there is no classification for the different shapes. The aim of this study was to evaluate the impact of different tumor shapes on GTR rates and outcome according to our proposed "Shape grading system." METHODS: In this retrospective single center study, the radiological outcome of nonfunctioning pituitary adenomas was assessed with respect to the following previously defined growth patterns: spherical (Shape I), oval (Shape II), dumbbell (Shape III), mushroom (Shape IV), and polylobulated (Shape V). RESULTS: A total of 191 patients were included (Shape I, n = 28 (15%); Shape II, n = 91 (48%); Shape III, n = 37 (19%); Shape IV, n = 12 (6%); Shape V, n = 23 (12%)). GTR was achieved in 101 patients (53%) with decreasing likelihood of GTR in higher shape grades (Shape I, n = 23 (82%); Shape II, n = 67 (74%); Shape III, n = 9 (24%); Shape IV, n = 2 (17%); Shape V, n = 0 (0%)). This correlated with larger tumor remnants, a higher risk of tumor recurrence/regrowth and therefore necessity of re-surgery and/or radiotherapy/radiosurgery. CONCLUSION: The "Shape grading system" may be used as a predictor of the outcome in nonfunctioning pituitary adenomas. The higher the "Shape grade," the higher the likelihood for lower GTR rates, larger tumor remnants, and need for further therapies.

Risk factors for early reherniation after lumbar discectomy with or without annular closure: results of a multicenter randomized controlled study.

BACKGROUND: Reherniation after lumbar discectomy is classified as a failure and occurs in 3 to 18% of cases. Various risk factors for reherniation such as age, sex, body mass index, smoking, and size of annular defect have been reported. The aim of this study was to identify risk factors for early reherniation after one-level lumbar discectomy with or without annular closure within 3 months after surgery. METHODS: This study is based on data analysis of a prospective, multicenter randomized controlled trial in Europe. Patients included underwent standard lumbar discectomy-with or without implantation of an annular closure device (ACD). Enrollment of 554 patients in 21 centers in Europe (Germany, Switzerland, Austria, Belgium, The Netherlands, and France) started in 2010 and was completed in October 2014. A total of 276 patients were randomized to the ACD group (ACG) and 278 patients to the control group (CG). RESULTS: Four (1.5%) symptomatic reherniations occurred in the ACG and 18 (6.5%) in the CG. In the overall population, a significant correlation was found with recurrent herniation for disc degeneration (Pfirrmann p = 0.009) and a trend for current smoker status (p = 0.07). In CG, age ≥ 50 years (p = 0.05) and disc degeneration (Pfirrmann p = 0.026, Kellgren and Lawrence p = 0.013) were predictive factors for reherniation. CONCLUSION: In the current study, risk factors for early recurrent disc herniation after lumbar discectomy were age ≥ 50 years and moderate disc degeneration. The annular closure device reduced the risk of early reherniation. TRIAL REGISTRATION: Clinicaltrials.gov NCT01283438.

Incidence and clinical impact of vertebral endplate changes after limited lumbar microdiscectomy and implantation of a bone-anchored annular closure device.

BACKGROUND: An annular closure device (ACD) could potentially prevent recurrent herniation by blocking larger annular defects after limited microdiscectomy (LMD). The purpose of this study was to analyze the incidence of endplate changes (EPC) and outcome after LMD with additional implantation of an ACD to prevent reherniation. METHODS: This analysis includes data from a) RCT study-arm of patients undergoing LMD with ACD implantation and b) additional patients undergoing ACD implantation at our institution. Clinical findings (VAS, ODI), radiological outcome (reherniation, implant integrity, volume of EPC) and risk factors for EPC were assessed. RESULTS: Seventy-two patients (37 men, 47 ± 11.63yo) underwent LMD and ACD implantation between 2013-2016. A total of 71 (99%) patients presented with some degree of EPC during the follow-up period (14.67 ± 4.77 months). In the multivariate regression analysis, localization of the anchor was the only significant predictor of EPC (p = 0.038). The largest EPC measured 4.2 cm3. Reherniation was documented in 17 (24%) patients (symptomatic: n = 10; asymptomatic: n = 7). Six (8.3%) patients with symptomatic reherniation underwent rediscectomy. Implant failure was documented in 19 (26.4%) patients including anchor head breakage (n = 1, 1.3%), dislocation of the whole device (n = 5, 6.9%), and mesh dislocation into the spinal canal (n = 13, 18%). Mesh subsidence within the EPC was documented in 15 (20.8%) patients. Seven (9.7%) patients underwent explantation of the entire, or parts of the device. CONCLUSION: Clinical improvement after LMD and ACD implantation was proven in our study. High incidence and volume of EPC did not correlate with clinical outcome. The ACD might prevent disc reherniation despite implant failure rates. Mechanical friction of the polymer mesh with the endplate is most likely the cause of EPC after ACD.

Changing the paradigm of intracranial hypertension in brain tumor patients: a study based on non-invasive ICP measurements.

BACKGROUND: The ultrasound based non-invasive ICP measurement method has been recently validated. Correlation of symptoms and signs of intracranial hypertension with actual ICP measurements in patients with large intracranial tumors is controversial. The purpose of this study was to assess ICP in patients with brain tumors, presenting with neurological signs and symptoms of elevated ICP and to further evaluate the value and utility of non-invasive ICP monitoring. METHODS: Twenty patients underwent non-invasive ICP measurement using a two-depth transcranial Doppler ultrasound designed to simultaneously compare pulse dynamics in the proximal (intracranial), and the distal (extracranial) intraorbital segments of the ophthalmic artery through the closed eyelid. RESULTS: Forty-eight measurements were analyzed. Radiological characteristics included tumor volume (range = 5.45-220.27cm3, mean = 48.81 cm3), perilesional edema (range = 0-238.27cm3, mean = 74.40 cm3), and midline shift (mean = 3.99 mm). All ICP measurements were in the normal range of 7-16 mmHg (ICPmean: 9.19 mmHg). The correlation of demographics, clinical and radiological variables in a bivariate association, showed a statistically significant correlation with neurological deficits and ICPmax (p = 0.02) as well as ICPmean (p = 0.01). The correlation between ICP and neurological deficits, showed a negative value of the estimate. The ICP was not increased in all cases, whether ipsilateral nor contralateral to the tumor. The multivariate model analysis demonstrated that neurological deficits were associated with lower ICPmax values, whereas maximum tumor diameter was associated with larger ICPmax values. CONCLUSIONS: This study demonstrated that ICP in patients with intracranial tumors and mass effect is not necessarily increased. Therefore, clinical signs of intracranial hypertension do not necessarily reflect increased ICP.

Drain type after burr-hole drainage of chronic subdural hematoma in geriatric patients: a subanalysis of the cSDH-Drain randomized controlled trial.

OBJECTIVE: Chronic subdural hematoma (cSDH) occurs more frequently in elderly patients, while older patient age is associated with worse postoperative outcome following burr-hole drainage (BHD) of cSDH. The cSDH-Drain trial showed comparable recurrence rates after BHD and placement of either a subperiosteal drain (SPD) or subdural drain (SDD). Additionally, an SPD showed a significantly lower rate of infections as well as iatrogenic parenchymal injuries through drain misplacement. This post hoc analysis aims to compare recurrence rates and clinical outcomes following BHD of cSDH and the placement of SPDs or SDDs in elderly patients. METHODS: The study included 104 patients (47.3%) 80 years of age and older from the 220 patients recruited in the preceding cSDH-Drain trial. SPDs and SDDs were compared with regard to recurrence rate, morbidity, mortality, and clinical outcome. A post hoc analysis using logistic regression, comparing the outcome measurements for patients < 80 and ≥ 80 years old in a univariate analysis and stratified for drain type, was further completed. RESULTS: Patients ≥ 80 years of age treated with an SDD showed higher recurrence rates (12.8%) compared with those treated with an SPD (8.2%), without a significant difference (p = 0.46). Significantly higher drain misplacement rates were observed for patients older than 80 years and treated with an SDD compared with an SPD (0% vs 20%, p = 0.01). Comparing patients older than 80 years to younger patients, significantly higher overall mortality (15.4% vs 5.2%, p = 0.012), 30-day mortality (3.8% vs 0%, p = 0.033), and surgical mortality (2.9% vs 1.7%, p = 0.034) rates were observed. Clinical outcome at the 12-month follow-up was significantly worse for patients ≥ 80 years old, and logistic regression showed a significant association of age with outcome, while drain type had no association with outcome. CONCLUSIONS: The initial findings of the cSDH-Drain trial and the findings of this subanalysis suggest that SPD may be warranted in elderly patients. As opposed to drain type, patient age (> 80 years) was significantly associated with worse outcome, as well as higher morbidity and mortality rates.

Outcome of nonneoplastic pituitary cysts during conservative monitoring and after surgery-a SwissPit study.

BACKGROUND: Nonneoplastic cysts of the pituitary are common incidental findings; however, best management remains controversial as they are often asymptomatic but eventually may cause symptoms. The aims of this study are to describe the course of conservative and surgical approaches, to assess timing and results of surgery, and to identify predictors for growth. METHODS: This retrospective study reviewed medical records from the Swiss Pituitary registry. Fifty patients (68% females; median 44 years old) fulfilled the criteria for inclusion. Three cohorts were defined: a conservative group (n = 28), a group who initially needed surgery (n = 18), and a group who had surgery during follow-up (n = 4). Transsphenoidal cyst evacuation was used in 95%; 68% had intraoperative MRI. All patients had standardized neuroradiological, endocrinological, and ophthalmological follow-up (mean 44 (7-151) months). RESULTS: Conservative follow-up of 30 (6-120) months showed cyst growth in 16% (4%/year) and spontaneous shrinkage in 19% (8%/year). Cyst-volumes changed - 0.95 to 1.45 cm3 per year. The probability of needing surgery was 5% per year. Larger cysts (> 1.4 cm3) and T1-hypo-/T2-hyper cyst contents were associated with higher probability for growth. Postoperatively, no remnant was seen in 82% during a follow-up of 53 months. Visual field deficiencies improved in 83%. Hypopituitarism recovered in up to 88%. But for a smaller complication rate, the outcome was not influenced by the use of the intraoperative MRI. CONCLUSIONS: Asymptomatic nonneoplastic pituitary cysts may be monitored; many lesions may shrink with time. Larger or T1-hypo-/T2-hyper cysts have higher growth rates. If indicated, surgery for nonneoplastic sellar cysts is a safe and efficient.

Changes in the cerebrospinal fluid lipid profile following subarachnoid hemorrhage in a closed cranium model: Correlations to cerebral vasospasm, neuronal cell death and Interleukin-6 synthesis. A pilot study.

BACKGROUND: Phospholipids and sphingolipids are cell membrane components, that participate in signaling events and regulate a wide variety of vital cellular processes. Sphingolipids are involved in ischemic stroke pathophysiology. Throughout cleavage of membrane sphingomyelin by sphingomyelinase in stroke patients, it results in increased Ceramide (Cer) levels in brain tissue. Different studies showed the evidence that sphingomyelinase with Cer production induces expression of interleukin (IL)-6 and have vasoconstrictive proprieties. With this study, we intend to evaluate cerebrospinal fluid (CSF) lipid profile changes in a rabbit closed cranium subarachnoid hemorrhage (SAH) model. METHODS: A total of 14 New Zealand white rabbits were randomly allocated either to SAH or sham group. In the first group SAH was induced by extracranial-intracranial shunting from the subclavian artery into the cisterna magna. Intracranial pressure (ICP) and arterial blood pressure were continuously monitored. Digital subtraction angiography of the basilar artery, CSF and blood samples were performed at day 0 pre SAH and on day 3 post SAH. The amount of IL-6 and various lipids in CSF were quantified using ELISA and Liquid Chromatography-Mass Spectrometry respectively. Cell death was detected in bilateral basal cortex, hippocampus (CA1 and CA3) using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). RESULTS: SAH Induction led to acute increase of ICP and increased delayed cerebral vasospasm (DCVS). At follow up CSF IL-6 levels showed a significant increase compared to baseline. Between baseline and follow up there were no significant differences in any of the measured CSF Lipids irrespective of subgroups. No relevant correlation was found between IL-6 and any of the sphingolipids. We found a correlation between baseline and follow up for the phospholipids phosphatidylethanolamine and phosphatidylcholine. CONCLUSIONS: Neuronal apoptosis, DCVS and IL-6 seems not to be related to changes in CSF lipid profiles except for PEA and PC in a rabbit closed cranium SAH model.

Implementation of an infection prevention bundle is associated with reduced surgical site infections in cranial neurosurgery.

OBJECTIVE: The objective of this study was to quantify surgical site infection (SSI) rates after cranial neurosurgery in a tertiary care hospital, identify risk factors for SSI, and evaluate the impact of standardized surveillance and an infection prevention bundle (IPB). METHODS: The authors compared SSI rates during 7 months before and after the intervention. The IPB included standardized patient preparation, perioperative antibiotic/antiseptic use, barrier precautions, coaching of surgeons, and the implementation of a specialized technical operation assistant team. RESULTS: Three hundred twenty-two unselected consecutive patients were evaluated before the IPB, and 296 were evaluated after implementation. Infection rates after 1 year decreased from 7.8% (25/322) to 3.7% (11/296, p = 0.03) with similar mortality rates (14.7% vs 13.8%, p = 0.8). The isolated bacteria included Staphylococcus aureus (42%), Cutibacterium acnes (22%), and coagulase-negative staphylococci (14%). Organ/space infections dominated with 67%, and mostly consisted of subdural empyema and meningitis/ventriculitis. Among the 36 SSIs, 13 (36%) occurred during hospitalization, and 29 (81%) within the first 3 months of follow-up. In multivariable analysis including established risk factors described in the literature, non-CNS neoplasia (odds ratio [OR] 3.82, 95% confidence interval [CI] 1.39-10.53), postoperative bleeding (OR 4.09, 1.44-11.62), operations performed by or under supervision of a senior faculty surgeon (OR 0.38, 0.17-0.84), and operations performed after the implementation of standardized surveillance and an IPB (OR 0.38, 0.17-0.85) significantly influenced the infection rate. CONCLUSIONS: The introduction of an IPB combined with routine surveillance and personal feedback was associated with a 53% reduced infection rate. The lower infection rates of senior faculty and the strong association between postoperative bleeding and infection underline the importance of both surgical experience as well as thorough supervision and coaching of younger surgeons.

The Subtemporal Approach to the Lateral Midbrain with and without Zygomatic Osteotomy: An Anatomical Study.

The subtemporal approach provides a narrow operative corridor to the crus cerebrum and adjacent structures of the crural, interpeduncular, and ambient cistern. Addition of a zygomatic osteotomy widens this narrow corridor and spares retraction of the temporal lobe. We investigate and compare the morphometric parameters of the subtemporal approach with versus without zygomatic osteotomy. On each side of four cadaveric heads, a temporal craniotomy was performed to gain access to the crus cerebrum and adjacent subarachnoid cisterns using a subtemporal approach. Operative corridor width and corridor working angle were measured with and without brain retraction on each specimen side. Next, a zygomatic osteotomy was performed followed by full downward reflection of the temporalis muscle and further drilling of the squamous part of the temporal bone. Lastly, operative corridor width and corridor working angle were measured again for comparison. The subtemporal operating corridor was (mean/SD): 5.8/2.6 mm without retraction, 11.4/4.3 mm with retraction, and 13.5/6.5° working angle. After addition of a zygomatic osteotomy, the operative corridor was 8/9.2/4.3 mm without retraction, 14.7/4.5 mm with retraction, 31.8/3.1° working angle. Zygomatic osteotomy significantly increased the operative corridor working angle of the subtemporal approach. Furthermore, we demonstrate a direct approach into the interpeduncular fossa. Clin. Anat. 32:710-714, 2019. © 2019 Wiley Periodicals, Inc.

Home-Time as a Surrogate Marker for Functional Outcome After Aneurysmal Subarachnoid Hemorrhage.

Background and Purpose­Commonly used tools to determine functional outcome after aneurysmal subarachnoid hemorrhage (aSAH) have limitations. Time spent at the patient's home has previously been proposed as a robust outcome measure after ischemic stroke. Here, we set out to validate home-time as an outcome measure after aSAH. Methods­We examined prospectively collected data from a nationwide multicenter registry of aSAH patients admitted to a tertiary neurosurgical department in Switzerland (Swiss SOS [Swiss Study on Aneurysmal Subarachnoid Hemorrhage]; 2009­2015). We calculated mean home-time (defined as days spent at home for the first 90 days after aSAH) and 95% CIs for each category of modified Rankin Scale at discharge and 1-year follow-up, using linear regression models to analyze home-time differences per modified Rankin Scale category. Results­We had home-time data from 1076 of 1866 patients (57.7%), and multiple imputation was used to fill-in missing data from the remaining 790 patients. Increasing home-time was associated with improved modified Rankin Scale scores at time of hospital discharge (P<0.0001) and at 1-year follow-up (P<0.0001). Within each of the 8 participating hospitals, the relationship between home-time and modified Rankin Scale was maintained. Conclusions­Home-time for the first 90 days after aSAH offers a robust and easily ascertainable outcome measure, discriminating particularly well across better recovery levels at time of hospital discharge and at 1-year follow-up. This measure complies with the modern trend of patient-centered healthcare and research, representing an outcome that is particularly relevant to the patient.

Predictors of In-Hospital Death After Aneurysmal Subarachnoid Hemorrhage: Analysis of a Nationwide Database (Swiss SOS [Swiss Study on Aneurysmal Subarachnoid Hemorrhage]).

BACKGROUND AND PURPOSE: To identify predictors of in-hospital mortality in patients with aneurysmal subarachnoid hemorrhage and to estimate their impact. METHODS: Retrospective analysis of prospective data from a nationwide multicenter registry on all aneurysmal subarachnoid hemorrhage cases admitted to a tertiary neurosurgical department in Switzerland (Swiss SOS [Swiss Study on Aneurysmal Subarachnoid Hemorrhage]; 2009-2015). Both clinical and radiological independent predictors of in-hospital mortality were identified, and their effect size was determined by calculating adjusted odds ratios (aORs) using multivariate logistic regression. Survival was displayed using Kaplan-Meier curves. RESULTS: Data of n=1866 aneurysmal subarachnoid hemorrhage patients in the Swiss SOS database were available. In-hospital mortality was 20% (n=373). In n=197 patients (10.6%), active treatment was discontinued after hospital admission (no aneurysm occlusion attempted), and this cohort was excluded from analysis of the main statistical model. In the remaining n=1669 patients, the rate of in-hospital mortality was 13.9% (n=232). Strong independent predictors of in-hospital mortality were rebleeding (aOR, 7.69; 95% confidence interval, 3.00-19.71; P<0.001), cerebral infarction attributable to delayed cerebral ischemia (aOR, 3.66; 95% confidence interval, 1.94-6.89; P<0.001), intraventricular hemorrhage (aOR, 2.65; 95% confidence interval, 1.38-5.09; P=0.003), and new infarction post-treatment (aOR, 2.57; 95% confidence interval, 1.43-4.62; P=0.002). CONCLUSIONS: Several-and among them modifiable-factors seem to be associated with in-hospital mortality after aneurysmal subarachnoid hemorrhage. Our data suggest that strategies aiming to reduce the risk of rebleeding are most promising in patients where active treatment is initially pursued. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT03245866.

Endplate changes after lumbar discectomy with and without implantation of an annular closure device.

BACKGROUND: The implantation of a bone-anchored annular closure device (ACD) might be associated with the developed new endplate changes (EPC) after surgery. METHODS: A post hoc analysis has been done in patients from a prospective randomized multicenter study. All patients underwent limited lumbar discectomy with intraoperative randomization into the groups limited lumbar discectomy alone or additional ACD implantation. Low-dose lumbar computed tomography (CT) and clinical investigations were performed preoperatively and 12 months after the operation. RESULTS: A total of 554 patients were randomized. After exclusion of dropouts, the per-protocol population included 493 patients (251 in the control group and 242 in the ACD group); the follow-up rate was ≥ 90%. The number of patients showing EPC at baseline was similar in both groups. The number of patients showing EPC and the total EPC lesion area significantly increased in both groups over time, but significantly increased more in the EPC group for the superior and inferior endplate (all P < 0.0001). There was no association of pre-existing number and size of EPC with sex, age, or smoking habits. Correlation of clinical variables showed no relation with number, size, and increase of EPC area after surgery. CONCLUSIONS: Patients with primary lumbar disc herniation show EPC in the corresponding segments. There is a significant increase of lesion number and size within 12 months after discectomy. This increase is significantly more pronounced in the ACD group. Presence and growth of EPC is not correlated with low-back pain or ODI.

Validation and accuracy of intraoperative CT scan using the Philips AlluraXper FD20 angiography suite for assessment of spinal instrumentation.

BACKGROUND: With the concept of the hybrid operating room gaining popularity, the authors adapted a hybrid angiographic suite with intraoperative computed tomography (iCT) to evaluate accuracy of pedicle screw placement in spinal fusion. This retrospective review examines how well iCT detected extrapedicular screw violation, to then allow repositioning and potentially avoid revision surgery. METHODS: A total of 36 consecutive patients underwent pedicle screw placement in posterior cervical, thoracic, and lumbosacral spinal fusions. All patients underwent iCT in the Philips AlluraXper FD20 angiography suite in the lumbar spine XperCT mode and postoperative conventional computed tomography (CT) scanning. Primary endpoints included the sensitivity and specificity of iCT in detecting pedicular violation characterized as minor, moderate, or severe when compared with postoperative CT. Secondary endpoint included the incidence of replaced screws during surgery and number of revision surgeries. RESULTS: Of 241 screws placed in 16 males and 20 females, iCT detected severe pedicle violation in 25 screws (10.4%); 16 screws were then repositioned during surgery. Sensitivity and specificity of iCT to detect severe screw malposition were 92.3% and 99.1%, respectively. No revision surgeries were performed in this series. CONCLUSIONS: In our series, iCT had high sensitivity and specificity in detecting severe screw malposition. As a valuable adjunct for intraoperative assessment of pedicle screw position, immediate intraoperative correction of misplaced screws then eliminated any revision surgery for our patients.

Figures of merit for self-beating filtered microwave photonic systems.

We present a model to compute the figures of merit of self-beating Microwave Photonic systems, a novel class of systems that work on a self-homodyne fashion by sharing the same laser source for information bearing and local oscillator tasks. General and simplified expressions are given and, as an example, we have considered their application to the design of a tunable RF MWP BS/UE front end for band selection, based on a Chebyshev Type-II optical filter. The applicability and usefulness of the model are also discussed.

Third-order linearization for self-beating filtered microwave photonic systems using a dual parallel Mach-Zehnder modulator.

We develop, analyze and apply a linearization technique based on dual parallel Mach-Zehnder modulator to self-beating microwave photonics systems. The approach enables broadband low-distortion transmission and reception at expense of a moderate electrical power penalty yielding a small optical power penalty (<1 dB).