Brain tissue oxygen plus intracranial pressure monitoring versus isolated intracranial pressure monitoring in patients with traumatic brain injury: an updated meta-analysis of randomized controlled trials.

BACKGROUND: Intracranial pressure (ICP) monitoring plays a key role in patients with traumatic brain injury (TBI), however, cerebral hypoxia can occur without intracranial hypertension. Aiming to improve neuroprotection in these patients, a possible alternative is the association of Brain Tissue Oxygen Pressure (PbtO2) monitoring, used to detect PbtO2 tension. METHOD: We systematically searched PubMed, Embase and Cochrane Central for RCTs comparing combined PbtO2 + ICP monitoring with ICP monitoring alone in patients with severe or moderate TBI. The outcomes analyzed were mortality at 6 months, favorable outcome (GOS ≥ 4 or GOSE ≥ 5) at 6 months, pulmonary events, cardiovascular events and sepsis rate. RESULTS: We included 4 RCTs in the analysis, totaling 505 patients. Combined PbtO2 + ICP monitoring was used in 241 (47.72%) patients. There was no significant difference between the groups in relation to favorable outcome at 6 months (RR 1.17; 95% CI 0.95-1.43; p = 0.134; I2 = 0%), mortality at 6 months (RR 0.82; 95% CI 0.57-1.18; p = 0.281; I2 = 34%), cardiovascular events (RR 1.75; 95% CI 0.86-3.52; p = 0.120; I2 = 0%) or sepsis (RR 0.75; 95% CI 0.25-2.22; p = 0.604; I2 = 0%). The risk of pulmonary events was significantly higher in the group with combined PbtO2 + ICP monitoring (RR 1.44; 95% CI 1.11-1.87; p = 0.006; I2 = 0%). CONCLUSIONS: Our findings suggest that combined PbtO2 + ICP monitoring does not change outcomes such as mortality, functional recovery, cardiovascular events or sepsis. Furthermore, we found a higher risk of pulmonary events in patients undergoing combined monitoring.

Assessment of the specificity of corvis biomechanical index-laser vision correction (CBI-LVC) in stable corneas after phototherapeutic keratectomy.

PURPOSE: The Corvis Biomechanical Index-Laser Vision Correction (CBI-LVC) is a biomechanical index to detect ectasia in post-refractive surgery patients (PRK, LASIK, SMILE). This study aims to evaluate the distribution of the CBI-LVC in stable patients who underwent Phototherapeutic Keratectomy (PTK) compared to PRK patients. METHODS: Patients who underwent PRK and PTK performed between 2000 and 2018 in Humanitas Research Hospital, Rozzano, Milan, Italy and remained stable for at least four years post-surgery were included. All eyes were examined with the Corvis ST (Oculus, Germany), whose output allows the calculation of the CBI-LVC. The distribution and specificity of the CBI-LVC in the two populations were estimated using a Wilcoxon Mann-Whitney test and compared. RESULTS: 175 eyes of 148 patients were included (85 eyes of 50 PTK patients and 90 eyes of 90 PRK patients). The distribution of CBI-LVC in the two groups showed a minor difference, with a median value in PRK patients of 0.000 (95% CI 0.000; 0.002) and 0.008 (95% CI 0.000; 0.037) in PTK patients (Mann-Whitney U test p = 0.023). The statistical analysis showed that the CBI-LVC provided a specificity of 92.22% in the PRK group, while in the PTK group it was 82.35%. Nevertheless, this difference was not statistically significant (Chi-squared test with Yates, p = 0.080). CONCLUSION: CBI-LVC provided similar specificity in stable PTK patients compared to those who underwent PRK. These results suggest that the CBI-LVC could be a useful tool to aid corneal surgeons in managing PTK patients.

Ectatic diseases.

Ectatic corneal disease (ECD) comprises a group of disorders characterized by progressive thinning and subsequent bulging of the corneal structure. Different phenotypes have been recognized, including keratoglobus, pellucid marginal degeneration (PMD), and keratoconus (KC). Keratoconus has been widely investigated throughout the years, but the advent of laser refractive surgery boosted an immediate need for more knowledge and research about ectatic diseases. This article discusses nomenclature of ectatic disease, etiology and pathogenesis, along with treatment options, with special focus ok KC and forme fruste keratoconus.

Natural history observations in moderate aortic stenosis.

BACKGROUND: The natural history of patients with moderate aortic stenosis (AS) is poorly understood. We aimed to determine the long-term outcomes of patients with moderate AS. METHODS: We examined patients with moderate AS defined by echocardiography in our healthcare system, and performed survival analyses for occurrence of death, heart failure (HF) hospitalization, and progression of AS, with accounting for symptoms, left ventricular dysfunction, and comorbidities. RESULTS: We examined 729 patients with moderate AS (median age, 76 years; 59.9 % men) with a median follow-up of 5.0 years (interquartile range: 2.0 to 8.1 years). The 5-year overall survival was 52.3 % (95 % confidence interval [CI]: 48.6 % to 56.0 %) and survival free of death or HF hospitalization was 43.2 % (95 % CI: 39.5 % to 46.9 %). Worse New York Heart Association (NYHA) functional class was associated with poor long-term survival, with mortality rates ranging from 7.9 % (95 % CI: 6.6-9.2 %) to 25.2 % (95 % CI: 20.2-30.3 %) per year. Among patients with minimal or no symptoms, no futility markers, and preserved left ventricular function, 5-year overall survival was 71.9 % (95 % CI: 66.4-77.4 %) and survival free of death or HF hospitalization was 61.4 % (95 % CI: 55.5-67.3 %). Risk factors associated with adverse events were age, NYHA class, low ejection fraction and high aortic valve velocity (all p < 0.05). CONCLUSIONS: Patients with moderate AS are at significant risk of death. Our findings highlight the need for more study into appropriate therapeutic interventions to improve the prognosis of these patients.

Effect of Corneal Tilt on the Determination of Asphericity.

Purpose: To quantify the effect of levelling the corneal surface around the optical axis on the calculated values of corneal asphericity when conic and biconic models are used to fit the anterior corneal surface. Methods: This cross-sectional study starts with a mathematical simulation proving the concept of the effect that the eye's tilt has on the corneal asphericity calculation. Spherical, conic and biconic models are considered and compared. Further, corneal asphericity is analysed in the eyes of 177 healthy participants aged 35.4 ± 15.2. The optical axis was determined using an optimization procedure via the Levenberg-Marquardt nonlinear least-squares algorithm, before fitting the corneal surface to spherical, conic and biconic models. The influence of pupil size (aperture radii of 1.5, 3.0, 4.0 and 5.0 mm) on corneal radius and asphericity was also analysed. Results: In computer simulations, eye tilt caused an increase in the apical radii of the surface with the increase of the tilt angle in both positive and negative directions and aperture radii in all models. Fitting the cornea to spherical models did not show a significant difference between the raw-measured corneal surfaces and the levelled surfaces for right and left eyes. When the conic models were fitted to the cornea, changes in the radii of the cornea among the raw-measured corneal surfaces' data and levelled data were not significant; however, significant differences were recorded in the asphericity of the anterior surfaces at radii of aperture 1.5 mm (p < 0.01). With the biconic model, the posterior surfaces recorded significant asphericity differences at aperture radii of 1.5 mm, 3 mm, 4 mm and 5 mm (p = 0.01, p < 0.01, p < 0.01 & p < 0.01, respectively) in the nasal temporal direction of right eyes and left eyes (p < 0.01, p < 0.01, p < 0.01 & p < 0.01, respectively). In the superior-inferior direction, significant changes were only noticed at aperture radii of 1.5 mm for both right and left eyes (p = 0.05, p < 0.01). Conclusions: Estimation of human corneal asphericity from topography or tomography data using conic and biconic models of corneas are affected by eyes' natural tilt. In contrast, the apical radii of the cornea are less affected. Using corneal asphericity in certain applications such as fitting contact lenses, corneal implant design, planning for refractive surgery and mathematical modelling when a geometrical centre of the eye is needed should be implemented with caution.

Correlation between different Scheimpflug-based lens densitometry analysis and effective phacoemulsification time in mild nuclear cataracts.

PURPOSE: To assess the correlations between preoperative Scheimpflug-based lens densitometry and effective phacoemulsification time (EPT) in age-related nuclear cataracts. DESIGN: Retrospective consecutive study. METHODS: The setting was the Ophthalmology Department, Hospital de Braga, Portugal. The study population included 50 eyes (42 patients) with age-related nuclear cataracts submitted to uneventful phacoemulsification surgery. Different analysis methods of Scheimpflug-based lens densitometry were performed: Pentacam Nucleus Staging (PNS) score with an ordinal scale from 0 to 5 and three-dimensional (3D), linear and region of interest (ROI) methods, which are displayed on an absolute scale (from 0 to 100%). EPT was calculated for the cataract surgery, which was performed by the same surgeon. Correlations between lens densitometry variables and EPT were determined using Pearson or Spearman correlation coefficients according to data normality. RESULTS: There were significant correlations between EPT and average density and maximum density variables derived from the 3D (r = 0.596, p < 0.001; r = 0.632, p < 0.001, respectively) and ROI (r = 0.527, p < 0.001; r = 0.575, p < 0.001, respectively) methods. The average density was the only parameter derived from the linear analysis that showed a significant correlation with EPT (r = 0.293, p = 0.039). The PNS score did not show a significant correlation with EPT (rho = 0.124, p = 0.390). CONCLUSION: The densitometric parameters based on the 3D method showed the highest correlations with EPT. The referred lens densitometric analysis approach may be used in preoperative assessment in order to predict EPT more efficiently in age-related nuclear cataracts.

Role of the corneal epithelium measurements in keratorefractive surgery.

PURPOSE OF REVIEW: Refractive surgery has stimulated considerable progress in corneal and anterior segment imaging, and optical characterization of the eye. From front surface corneal topography, we evolved to three-dimensional corneal tomography with limbus to limbus characterization of the front and back corneal surfaces and pachymetric mapping. Corneal anatomical evaluation has further evolved to layered or segmental tomography with the ability to characterize corneal epithelial thickness profile and the elevation of stromal front surface. Further characterization of even more specific structures, such as Bowman's layer and Descement's membrane, has been also demonstrated. The applications of such understanding in keratorefractive surgery are reviewed. RECENT FINDINGS: Understanding the corneal epithelial profile is of interest in many areas of ophthalmology, especially in refractive surgery. The most relevant applications include screening candidates at higher risk for complications (i.e. progressive ectasia and tear dysfunction syndrome), planning primary procedures, enhancements, and therapeutic surgery, and also postoperatively understanding the wound healing and clinical outcomes. SUMMARY: Corneal epithelial thickness was first available using digital very-high-frequency ultrasound. Advances in anterior segment optical coherence tomography enabled such fundamental evaluation, which accelerated progress. Such knowledge significantly impacts safety and efficacy of refractive surgery, and also allows for significant improvement for therapeutic procedures. VIDEO ABSTRACT.

The role of cardiovascular magnetic resonance in takotsubo syndrome.

Takotsubo syndrome (TS) is a transient form of left ventricular dysfunction associated with a distinctive contraction pattern in the absence of significant coronary artery disease triggered by stressful events. Several aspects of its clinical profile have been described but it still remains difficult to quickly establish the diagnosis at admission.Cardiovascular magnetic resonance (CMR) has achieved great improvements in the last years, which in turn has made this imaging technology more attractive in the diagnosis and evaluation of TS. With its superior tissue resolution and dynamic imaging capabilities, CMR is currently the most useful imaging technique in this setting.In this review, we propose to comprehensively define the role of CMR in the evaluation of patients with TS and to summarize a set of criteria suitable for diagnostic decision making in this clinical setting.

Impact of Chest Pain Protocol with Access to Telemedicine on Implementation of Pharmacoinvasive Strategy in a Private Hospital Network.

BACKGROUND: Brazilian registries have shown a gap between evidence-based therapies and real treatments. We aim to compare the use of the pharmacoinvasive strategy and mortality in patients with ST elevation myocardial infarction (STEMI) transferred pre- and post-chest pain protocol with access to telemedicine (CPPT) in a private hospital network. MATERIALS AND METHODS: A CPPT was implemented in 22 private emergency departments in 2012. Emergency physicians and nurses of all facilities were trained to disseminate the information to comply with a chest pain protocol focusing on reperfusion therapy (pharmacoinvasive strategy) for STEMI. To conduct clinical discussions using telemedicine, a cardiologist from a reference hospital in cardiology (RHC) was available 24 h/day, 7 days/week. Using the database of all consecutive admissions, we compared the data of patients with STEMI transferred to the RHC in 2011 (pre-CPPT) and 2013-2014 (post-CPPT). RESULTS: We included 376 patients (113 pre-CPPT and 263 post-CPPT) with STEMI. All patients admitted in the RHC were transferred from the 22 emergency departments. Comparing pre-CPPT and post-CPPT, we did not find differences regarding age, gender, hypertension, dyslipidemia, diabetes, smoking, previous myocardial infarction, or Killip classification. However, the use of CPPT was associated with a greater use of pharmacoinvasive strategy (55.8% versus 38%; p = 0.002) and a trend toward lower in-hospital mortality (3% versus 8%; p = 0.06). CONCLUSIONS: The implementation of a CPPT was associated with a significant increase in the use of pharmacoinvasive strategy in patients with STEMI and a trend toward reduced in-hospital mortality in a private hospital network.

Investigation of How Corneal Densitometry Artefacts Affect the Imaging of Normal and Keratoconic Corneas.

PURPOSE: To investigate corneal densitometry artefacts found in Pentacam Scheimpflug scans and their potential effect on assessing keratoconic (KC) corneas compared to normal (N) corneas. METHODS: The current study utilises Pentacam data of 458 N eyes, aged 35.6 ± 15.8 (range 10-87), referred to as the "N group", and 314 KC eyes, aged 31.6 ± 10.8 (range 10-72), referred to as the "KC group", where densitometry data were extracted and analysed via a custom-built MATLAB code. Radial summations of the densitometry were calculated at diameters ranging from 0.5 mm to 5.0 mm. The minimum normalised radial summation of densitometry (NRSD) value and angle were determined at each diameter and then linked. KC cone locations and areas of pathology were determined, and a comparison between N and KC groups was carried out both within the averaged area of pathology and over the corneal surface. RESULTS: Joining minimum NRSD trajectory points marked a clear distortion line pointing to the nasal-superior direction at 65° from the nasal meridian. The findings were found to be independent of eye laterality or ocular condition. Consistency was detected in the right and left eyes among both the N and KC groups. The location of the KC cone centre and the area of pathology were determined, and the densitometry output was compared both within the area of pathology and over the whole cornea. When the average densitometry was compared between N and KC eyes within the KC area of pathology, the N group recorded a 16.37 ± 3.15 normalised grey-scale unit (NGSU), and the KC group recorded 17.74 ± 3.4 NGSU (p = 0.0001). However, when the whole cornea was considered, the N group recorded 16.71 ± 5.5 NGSU, and the KC group recorded 15.72 ± 3.98 NGSU (p = 0.0467). A weak correlation was found between the Bad D index and NGSU when the whole measured cornea was considered (R = -0.01); however, a better correlation was recorded within the KC area of pathology (R = 0.21). CONCLUSIONS: Nasal-superior artefacts are observed in the densitometry Pentacam maps, and analysis shows no significant differences in their appearance between N or KC corneas. When analysing KC corneas, it was found that the cone positions are mostly on the temporal-inferior side of the cornea, opposite to the densitometry artefact NRSD trajectory. The analysis suggests that the corneal densitometry artefacts do not interfere with the KC area of pathology as it reaches its extreme in the opposite direction; therefore, weighting the densitometry map to increase the contribution of the inferior-temporal cornea and decreasing that of the superior-nasal area would improve the classification or identification of KC if densitometry is to be used as a KC metric.

Combined Rotating Ultra-High-Resolution Spectral Domain OCT and Scheimpflug Imaging for In Vivo Corneal Optical Biopsy.

PURPOSE: This article introduces the Pentacam® Cornea OCT (optical coherence tomography). This advanced corneal imaging system combines rotating ultra-high-resolution spectral domain OCT with sub- 2-micron axial resolution and Scheimpflug photography. The purpose of this study is to present the first experience with the instrument and its potential for corneal diagnostics, including optical biopsy. METHODS: In this prospective study, the Pentacam® Cornea OCT was used to image the corneas of seven patients. The novel wide-angle pericentric scan system enables optimal OCT imaging performance for the corneal layer structure over the entire width of the cornea, including the limbal regions. A detailed analysis of the resulting images assessed the synergism between the OCT and Scheimpflug photography. RESULTS: The Pentacam® Cornea OCT demonstrated significantly improved image resolution and ability to individualize corneal layers with high quality. There is a synergism between the OCT high-definition signal to individualize details on the cornea and Scheimpflug photography to detect and quantify corneal scattering. The noncontact exam was proven safe, user-friendly, and effective for enabling optical biopsy. CONCLUSIONS: Pentacam® Cornea OCT is an advancement in corneal imaging technology. The ultra-high-resolution spectral domain OCT and Scheimpflug photography provide unprecedented detail and resolution, enabling optical biopsy and improving the understanding of corneal pathology. Further studies are necessary to compare and analyze the tomographic reconstructions of the cornea with the different wavelengths, which may provide helpful information for diagnosing and managing corneal diseases.

Keratoconus and Corneal Ectasia with Relatively Low Keratometry.

INTRODUCTION: The study aims to demonstrate and estimate the prevalence of clinical corneal ectasia and keratoconus (KC) in patients with relatively low keratometry (low-K KC). METHODS: In a retrospective, analytical, and non-interventionist study, one eye was randomly selected from 1054 patients from the original Tomographic Biomechanical Index (TBIv1) study and the external validation (from Rio de Janeiro, Brazil, and Milan, Italy clinics). Patients were stratified into three groups. Group 1 included 736 normal patients, and groups 2 and 3 included 318 patients with clinical KC in both eyes, divided into low-K KC (90 patients) and high-K KC (228 patients), respectively. All patients underwent a comprehensive ophthalmological evaluation along with Pentacam and Corvis ST (Oculus, Wetzlar, Germany) examinations. Cases with maximum mean zone 3 mm keratometry (Kmax zone mean 3 mm) lower than 47.6 diopters (D) were considered as low-keratometry keratoconus, and cases with Kmax zone mean 3 mm higher than 47.6 D were regarded as high-keratometry keratoconus. RESULTS: Ninety (28.30%) of the 318 KC group presented ectasia with low-keratometric values (low-Kmax). The average age in the normal group was 39.28 years (range 6.99-90.12), in the low-Kmax KC group it was 37.49 (range 13.35-78.45), and in the high-Kmax KC group it was 34.22 years (range 12.7-80.34). Mean and SD values and median (range), respectively, of some corneal tomographic and biomechanical parameters evaluated from the low-Kmax KC group were as follows: Belin-Ambrósio enhanced ectasia display (BAD-D) 3.79 ± 1.62 and 3.66 (0.83-9.73); Pentacam random forest index (PRFI) 0.78 ± 0.25 and 0.91 (0.05-1); corneal biomechanical index (CBI) 0.58 ± 0.43 and 0.75 (0-1); TBI 0.93 ± 0.17 and 1 (0.35-1); and stiffness parameter at A1 (SP-A1) 86.16 ± 19.62 and 86.05 (42.94-141.66). CONCLUSION: Relatively low keratometry, with a Kmax lower than 47.6 D, can occur in up to 28.30% of clinical keratoconus. These cases have a less severe presentation of the disease. Future studies involving larger populations and prospective designs are necessary to confirm the prevalence of keratoconus with low keratometry and define prognostic factors in such cases.

Ventriculo - Gallbladder shunt.

INTRODUCTION: Permanent liquor diversion is associated with a high risk of failure and often requires re-intervention. The ventriculo-gallbladder shunt (VGS) has been recognized as a last-resort alternative for treating hydrocephalus when the peritoneum or other distal sites are no longer suitable for receiving shunts. This article aims to report a case from a neurosurgery referral service in Brazil and review the literature on this issue. METHODS: A systematic literature review was conducted in accordance with the PRISMA statement. The PubMed, Embase, and Web of Science databases were searched for data screening and extraction. The reported case was conducted with ethical approval from the neurosurgical hospital's ethics committee. RESULTS: G.B.S, male, 43 years old, no comorbidities, who has been dealing with a 12-year history of hydrocephalus, with post-surgical chronic fungal meningitis. Two years ago, he underwent a ventriculoatrial shunt (VAS) placement due to multiple ventriculoperitoneal shunt (VPS) failures. Endocarditis was suspected, and the VAS was removed. As an alternative, VGS was implanted 6 months ago, and since then, there has been no need for a new system review. The gallbladder has an absorptive capacity of 1500 cc of liquid daily, which is more than the normal daily production of cerebrospinal fluid (CSF). Therefore, it is a good alternative when the ventriculoperitoneal shunt is not feasible due to postsurgical peritoneal adhesions or when there are contraindications for ventriculoatrial shunts. CONCLUSION: VGS is an alternative for patients who cannot undergo the most common surgical interventions, such as VPS.

Endoscopic surgery for craniosynostosis: A systematic review and single-arm meta analysis.

BACKGROUND: Craniosynostosis, a developmental craniofacial anomaly, can impair brain development and cause abnormal skull shape due to premature closure of one or more cranial sutures. Traditional surgical treatments have evolved from open operations to minimally invasive endoscopic techniques. This systematic review and meta-analysis aim to evaluate the effectiveness and safety of the endoscopic approach in craniosynostosis correction. METHODS: Adhering to Cochrane Group standards and the PRISMA framework, this review utilized databases like PubMed, Embase, and Web of Science, focusing on clinical and surgical outcomes of endoscopic craniosynostosis operations up to December 2023. Inclusion criteria emphasized studies with at least five patients undergoing endoscopic procedures, while exclusion criteria involved non-English papers, incomplete texts, and overlapping data. Statistical analysis used R software with various packages, and methodological bias was assessed using the ROBINS-I framework. RESULTS: The review included 30 studies (4 prospective, 26 retrospective) with 2561 patients. The median age at operation was 3.20 months. Findings showed a mean operative time of 68.06 min, median hospital stay of 1.28 days, and mean blood loss of 29.89 ml. Blood transfusion was required in 9.97% of cases. Helmet therapy post-operation was common, with a median duration of 9 months. The rate of postoperative complications was 1.86%, and the reoperation rate was 3.07%. No procedure-related mortality was observed. The study noted substantial variations in the handling of craniosynostosis and a lack of consensus on the optimal timing and surgical approach. CONCLUSION: Endoscopic techniques for craniosynostosis repair demonstrate safety and effectiveness, characterized by low complication risks and favorable surgical outcomes. However, due to the limitations of observational studies and inherent heterogeneity, further comprehensive and controlled trials are needed to validate these findings and understand the long-term outcomes of the endoscopic approach.

Simultaneous Single-Trajectory Endoscopic Biopsy and Third Ventriculostomy in Pineal Region Tumors: A Systematic Review and Single Arm Meta-Analysis.

OBJECTIVE: To assess the efficacy and surgical outcomes of the simultaneous single-trajectory endoscopic biopsy and third ventriculostomy (ETV) in pineal region tumors. METHODS: A systematic review and meta-analysis adhering to Cochrane Standards and PRISMA framework were conducted. PubMed, Embase, and Web Of Science databases were searched until December 2023. Outcomes included rate of histopathologic diagnosis success, ETV success, complications, required VPS, and mortality. RESULTS: Seventeen studies (N = 388) met inclusion criteria. Histopathologic diagnosis success rate was 90% for general population (95% CI: 86%-95%; I2 = 42%) and 94% for pediatric patients (95% CI: 89%-98%; I2 = 19%). ETV Success rate was 93% (95% CI: 88%-97%; I2 = 60%). An estimated risk of postoperative ETV complications was found to be 16% for the general population (95% CI: 5%-28%; I2 = 90%) and 5% for pediatric patients (95% CI: 0%-13%; I2 = 51%). The risk of requiring VPS was estimated as 2% (95% CI: 0%-4%; I2 = 39%) and for the pediatric population it was 7% (95% CI: 0%-16%; I2 = 69%). Mortality risk was found to be 1% (95% CI: 0%-3%; I2 = 0%). CONCLUSIONS: Simultaneous endoscopic biopsy and ETV demonstrated high diagnostic and therapeutic success rates. The procedure's safety profile, with low mortality and complications, supports its role in treating hydrocephalus associated to pineal region tumors. Subgroup analyses revealed higher diagnostic success rates and required VPS in the pediatric population, whilst it had lower complication rates.

Active Versus Passive Drainage Systems for Subdural Hematomas: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: Chronic subdural hematoma (CSDH) management involves various surgical techniques, with drainage systems playing a pivotal role. While passive drainage (PD) and active drainage (AD) are both used, their efficacy remains contentious. Some studies favor PD for lower recurrence rates, while others suggest AD superiority. A systematic review and meta-analysis were conducted to address this controversy, aiming to provide clarity on optimal drainage modalities post-CSDH evacuation. METHODS: This systematic review and meta-analysis followed preferred reporting items for systematic reviews guidelines, searching PubMed, Embase, and Web of Science until February 2024. Inclusion criteria focused on studies comparing active vs PD for subdural hematomas. Data extraction involved independent researchers, and statistical analysis was conducted using R software. The assessment of risk of bias was performed using the Risk of Bias in Non-Randomized Studies of Interventions framework and the Risk Of Bias 2 tool. RESULTS: In this meta-analysis, involving 1949 patients with AD and 1346 with PD, no significant differences were observed in recurrence rates between the active (13.6%) and passive (16.4%) drainage groups (risk ratio [RR] = 0.87; 95% CI: 0.58-1.31). Similarly, for complications, infection, hemorrhage, and mortality, no significant disparities were found between the 2 drainage modalities. Complication rates were 7.5% for active and 12.6% for PD (RR = 0.74; 95% CI: 0.36-1.52). Infection rates were available for 635 patients of the active group, counting for 2% and 2.6%, respectively (RR = 0.98; 95% CI: 0.24-4.01). Hemorrhage rates were also available for 635 patients of the active group, counting for 1.1% and 2.2%, respectively (RR = 0.44; 95% CI: 0.11-1.81). Mortality rates were 2.7% and 2.5%, respectively (RR = 0.94; 95% CI: 0.61-1.46). CONCLUSION: Our study found no significant difference between passive and AD for managing complications, recurrence, infection, hemorrhage, or mortality in CSDH cases. Further large-scale randomized trials are needed for clarity.

In Vivo Corneal Stiffness Mapping by the Stress-Strain Index Maps and Brillouin Microscopy.

The study of corneal stiffness in vivo has numerous clinical applications such as the measurement of intraocular pressure, the preoperative screening for iatrogenic ectasia after laser vision correction surgery and the diagnosis and treatment of corneal ectatic diseases such as keratoconus. The localised aspect of the microstructure deterioration in keratoconus leading to local biomechanical softening, corneal bulging, irregular astigmatism and ultimately loss of vision boosted the need to map the corneal stiffness to identify the regional biomechanical failure. Currently, two methods to map the corneal stiffness in vivo are integrated into devices that are either already commercially available or about to be commercialised: the stress-strain index (SSI) maps and the Brillouin Microscopy (BM). The former method produces 2D map of stiffness across the corneal surface, developed through numerical simulations using the corneal shape, its microstructure content, and the deformation behaviour under air-puff excitation. It estimates the whole stress-strain behaviour, making it possible to obtain the material tangent modulus under different intraocular pressure levels. On the other hand, BM produces a 3D map of the corneal longitudinal modulus across the corneal surface and thickness. It uses a low-power near-infrared laser beam and through a spectral analysis of the returned signal, it assesses the mechanical compressibility of the tissue as measured by the longitudinal modulus. In this paper, these two techniques are reviewed, and their advantages and limitations discussed.

Corneal Biomechanics Losses Caused by Refractive Surgery.

Recent advances, specifically in the understanding of the biomechanical properties of the cornea and its response to diseases and surgical interventions, have significantly improved the safety and surgical outcomes of corneal refractive surgery, whose popularity and demand continue to grow worldwide. However, iatrogenic keratectasia resulting from the deterioration in corneal biomechanics caused by surgical interventions, although rare, remains a global concern. On one hand, in vivo biomechanical evaluation, enabled by clinical imaging systems such as the ORA and the Corvis ST, has significantly improved the risk profiling of patients for iatrogenic keratectasia. That is despite the fact the biomechanical metrics provided by these systems are considered indicators of the cornea's overall stiffness rather than its intrinsic material properties. On the other hand, new surgical modalities including SMILE were introduced to offer superior biomechanical performance to LASIK, but this superiority could not be proven clinically, creating more myths than answers. The literature also includes sound evidence that tPRK provided the highest preservation of corneal biomechanics when compared to both LASIK and SMILE. The aim of this review is twofold; to discuss the importance of corneal biomechanical evaluation prior to refractive surgery, and to assess the current understanding of cornea's biomechanical deterioration caused by mainstream corneal refractive surgeries. The review has led to an observation that new imaging techniques, parameters and evaluation systems may be needed to reflect the true advantages of specific refractive techniques and when these advantages are significant enough to offer better protection against post-surgery complications.

Biomechanics in Keratoconus Diagnosis.

Purpose: To prospectively review the importance of biomechanical assessment in the screening, diagnosis, prognosis, individualized planning, and clinical follow-up for ectatic corneal diseases.Methods: We demonstrate two commercially available devices to assess the corneal biomechanics in vivo, the Ocular Response Analyzer (ORA, Reichester, NY, USA) and the Corvis ST (Oculus, Wetzlar, Germany). Novel devices have been demonstrated to provide in vivo biomechanical measurements, including Brillouin optical microscopy and OCT elastography. Conclusion: The integration of biomechanical data and other data from multimodal refractive imaging using artificial intelligence demonstrated the ability to enhance accuracy in diagnosing ectatic corneal diseases.