Optic Nerve Sheath Research Articles

The impact of demographics and positioning on the imaging features of the optic nerve sheath and ophthalmic vessels

BackgroundThere are significant discrepancies in the optic nerve sheath diameter (ONSD) reported in the literature. We aimed to determine the ultrasonographic imaging features of ONSD and ophthalmic vessels in a healthy population, using a standardized protocol, and to estimate the effect of demographics and positioning changes on imaging measurements.MethodsWe measured the mean values of the ONSD in supine and sitting position and the Doppler imaging parameters of the ophthalmic, central retinal and short posterior ciliary arteries. Inter-observer reliability was assessed using intraclass correlation coefficient (ICC). Linear regression models were fitted to predict the effect of demographic and clinical determinants on the imaging features.ResultsA total of 50 measurements were obtained for each observer. The mean ONSD was 5.9 mm and there was a mean reduction of 0.2 mm when assessed in sitting position (p < 0.001). Doppler analysis showed higher peak-systolic velocity and resistive index in the ophthalmic artery (35.6 cm/s vs. 12.0 cm/s; 0.78 vs. 0.70) compared to the central retinal artery (p < 0.001). Age, sex, heart rate and systolic blood pressure were significant determinants of the imaging features, with ONSD being larger in males (p < 0.001) and increasing with heart rate (p = 0.001). ICC estimates indicated ‘good’ inter-observer reliability of the ONSD and the ophthalmic and central retinal arteries velocities and resistance.ConclusionsOur findings suggest a significant impact of patient demographics and positioning during ultrasonography on the normal imaging features of the ONSD and ophthalmic vessels. The heterogeneity in methodology and clinical cohorts may justify previous discrepancies in the literature. These findings can assist in the interpretation of imaging features in clinical settings and in the standardization of point of care ONSD ultrasonography.

The predictive value of optic nerve sheath diameter measurement via ultrasound for intracerebral hemorrhage complicated by cerebral-cardiac syndrome

ObjectiveThis study aims to evaluate the clinical significance of ultrasound-based measurement of optic nerve sheath diameter (ONSD) in predicting intracerebral hemorrhage (ICH) complicated by cerebral-cardiac syndrome (CCS).MethodsPatients with ICH and who were treated in the intensive care unit (ICU) at Shijiazhuang People’s Hospital between October 2021 and November 2022 were included in this study. Participants were divided into two groups: those with CCS and those without. Various clinical parameters, including sex, age, electrocardiogram (ECG) findings, myocardial markers, B-type natriuretic peptide (BNP) levels, Glasgow Coma Scale (GCS) score, ONSD, hematoma volume, and midline shift, were assessed. A binary logistic regression model and receiver operating characteristic (ROC) curve analysis were employed to determine the predictive value of each risk factor for ICH complicated by CCS.ResultsONSD measurements differed significantly between males and females, with males exhibiting larger ONSD values. Additionally, significant differences were observed in ONSD, hematoma volume, midline shift, and GCS scores between the CCS and non-CCS groups. A direct correlation was identified between ONSD and both hematoma volume and midline shift. Multiple regression analysis demonstrated that ONSD, hematoma volume, and GCS score are independent risk factors for predicting ICH complicated by CCS. ROC curve analysis for ONSD in predicting ICH with CCS revealed an area under the curve (AUC) of 0.80, with an optimal cutoff value of 5.88 cm, yielding a sensitivity of 83% and a specificity of 79%. When ONSD, hematoma volume, and GCS score were combined, the predictive accuracy improved, with an AUC of 0.880.ConclusionMales tend to have larger ONSD measurements compared to females. Ultrasound is a valuable tool for measuring ONSD, comparable to computed tomography, and is useful in detecting intracranial hypertension and mass effect. ONSD, hematoma volume, and GCS score are independent predictors of ICH complicated by CCS, and their combined use enhances predictive accuracy.

Diagnostic Role of Tissue Biopsy in Leukaemic or Lymphomatous Infiltrative Optic Neuropathy: A Case Report and Systematic Review of Literature

Purpose: To explore the role of tissue biopsy in diagnosing leukemic or lymphomatous infiltrative optic neuropathy through a systematic literature review and presentation of a new case. Methods: A systematic literature review was conducted using PubMed, Scopus, and Google Scholar databases to identify cases of leukemic or lymphomatous optic neuropathy in which optic nerve or sheath biopsy was performed. A newly reported case was also included. Results: A total of 420 studies were identified, with 26 meeting inclusion criteria. In total 29 patients were included, with a mean age of 55.9 years. Of these, 48.3% had a known history of leukemia or lymphoma, and 50% were in remission at presentation. Imaging showed optic nerve enhancement and enlargement in most cases. Biopsies were performed on the optic nerve, sheath, chiasm, tract, or surrounding orbital tissue. Direct nervous tissue biopsies (optic nerve, chiasm, or tract) were diagnostic in 100% of cases, while only 18.2% of sheath biopsies were diagnostic. Visual outcomes were poor, with many presenting with no light perception. Postoperatively, vision remained stable in 40%, deteriorated in 20.7%, and improved in 17.2%. Discussion: Tissue biopsy remains a critical last-line investigation for diagnosing leukemic or lymphomatous optic neuropathy when noninvasive methods remain inconclusive. While highly diagnostic, optic nerve biopsy carries visual risk, especially for patients with residual vision. Direct nerve biopsy is recommended for severe vision loss, while a more cautious surgical approach, considering alternative diagnostic techniques, is advised for those with partially preserved vision. Optic nerve sheath biopsy, though theoretically safer, has a limited diagnostic yield.

Resection of Meningiomas Invading the Cavernous Sinus: Treatment Strategy and Clinical Outcomes

Background/Objectives: Resection of tumors invading the cavernous sinus (CS) carries a risk of injury to the cranial nerves and internal carotid artery. Therefore, radical surgery involving lesions around the CS remains challenging, especially for lesions invading the CS, optic sheath, and oculomotor cave. Here, we describe a surgical strategy for meningiomas invading these structures and report on the clinical outcomes. Methods: Surgical resection was indicated in patients with neurological symptoms or rapid tumor growth for the restoration of cranial nerve function. We investigated 13 patients who had preoperative images of CS invasion, underwent surgical resection, and were followed-up with magnetic resonance imaging for at least 1 year between July 2017 and July 2024. Their preoperative symptoms, postoperative course, adjuvant therapy, postoperative complications, degree of resection, and recurrence were evaluated. Results: The mean patient age was 59.1 years (range, 23–73 years), and 10 were female. Major preoperative symptoms included oculomotor nerve paresis in 8 patients (61.5%), abducens nerve paresis in 6 (46.2%), visual disturbance in 7 (53.8%), and brain swelling in 3 (23.1%). These symptoms improved at least partially after surgery in 7 (87.5%), 5 (83.3%), 7 (100%), and 3 (100%) patients, respectively. Major postoperative complications included contralateral visual deterioration in 1 patient (7.7%) and brief transient slight hemiparesis caused by internal carotid vasospasm or dissection in 2 (15.4%). Four patients with residual atypical meningioma in the CS underwent intensity-modulated radiotherapy (IMRT). The lesions in 6 patients recurred or regrew, resulting in additional treatment with stereotactic radiosurgery in 2 patients, IMRT in 3, and resection in 1. Conclusions: Our surgical strategy for the surgical resection of meningiomas in and around the CS for the restoration of cranial nerve function is safe and effective, with only transient acceptable injuries. Even if the tumor in the CS is too stiff to be removed, it is important to open the optic nerve sheath and oculomotor cave widely to effectively remove the tumor.

The Role of Ultrasonographic Assessment of Optic Nerve Sheath Diameter in Prediction of Sepsis-Associated Encephalopathy: Prospective Observational Study.

Ultrasonographic optic nerve sheath diameter (ONSD) is a satisfactory noninvasive intracranial pressure (ICP) monitoring test. Our aim was to evaluate ONSD as an objective screening tool to predict and diagnose ICP changes early in sepsis-associated encephalopathy (SAE). Our prospective observational study was conducted on patients with sepsis, and after intensive care unit (ICU) admission, the time to diagnose SAE was recorded, and patients were divided into a non-SAE group including conscious patients with sepsis and a SAE group including patients with sepsis with acute onset of disturbed conscious level. ONSD was measured within 24h of ICU admission for all patients and then every other day for up to 10 consecutive days until ICU discharge or death. The primary outcome was to compare ONSD measurements of both groups to find if there was a correlation between ONSD and SAE occurrence. Eighty-nine patients with sepsis were divided into a non-SAE group (n = 45) and an SAE group (n = 44). ONSD showed a statistically significant difference at day 0 and a highly significant difference at days 2, 4, 6, 8, and 10. Day 2 ONSD had the best accuracy for predicting SAE, with a cutoff > 5.2mm (sensitivity of 93.2%, specificity of 100%), a statistically positive correlation with the Sequential Organ Failure Assessment score (r = 0.485, P < 0.001) and ICU length of stay (r = 0.238, P < 0.001), and a statistically significant wider in patients who died compared to those who survived (P < 0.001). ONSD could be an objective screening method for early diagnosis of SAE, with a cutoff > 5.2mm. Trial registration NCT05849831 ( https://clinicaltrials.gov/study/NCT05849831 ).

The Role of Optic Nerve Sheath Diameter in Differential Diagnosis in Patients with Headache, A Prospective, Randomized Controlled Study

The Role of Optic Nerve Sheath Diameter in Differential Diagnosis in Patients with Headache, A Prospective, Randomized Controlled Study

Post-craniotomy intracranial pressure monitoring: a novel approach combining optic nerve sheath diameter ultrasonography and cervical-cerebral arterial ultrasound

ObjectiveElevated intracranial pressure (ICP), a common complication in traumatic brain injuries (TBI), can lead to optic nerve sheath diameter (ONSD) enlargement and flow spectrum changes from the internal carotid artery (ICA) to middle cerebral artery (MCA). This study will investigate the use of Cervical-Cerebral Arterial Ultrasound (CCAU) for non-invasive ICP assessment and evaluating the related indices’ clinical utility in TBI patients with decompressive craniotomy (DC).MethodsONSD and flow spectrum changes were measured within 24 h after DC in 106 patients via ultrasonic ONSD measurement and CCAU, simultaneously. Intracranial pressures were invasively monitored, using a microsensor or ventricular catheter as the gold standard. Patients were classified into two groups, namely the normal group and the elevated group, based on distinct intracranial pressure thresholds of 15 mmHg, 20 mmHg and 22 mmHg. Subsequently, Bland Altman plot used for evaluating agreement between estimate for ICP (ICPe) and invasive ICP (ICPi). Then, the correlation between ONSD, MCAPI (pulsatility index of MCA), PI-ratio (MCAPI/ICAPI), and ICPe was examined through linear regression analysis. Finally, receiver operator characteristic curves (ROC) were also analyzed for different indexes and their combinations (using logistic model).ResultsSignificant differences were observed between the normal and elevated ICP groups with respect to ONSD, PI-ratio, MCAPI and MCAFVd (diastolic flow velocity of MCA) (p &amp;lt; 0.05). The correlation coefficients for the relationships between ONSD, PI ratio, FVdMCA, and PI with ICPi were 0.62, 0.33, 0.32 and 0.21, respectively, each demonstrating statistical significance (p &amp;lt; 0.05). Analysis of the ROC curves demonstrated that the area under the curve (AUC) for predicting elevated ICPi at thresholds of 15 mmHg, 20 mmHg, and 22 mmHg via combined ultrasonographic measurements of the PI ratio and ONSD was the largest, specifically 0.74 (95% CI: 0.65–0.82), 0.77 (95% CI: 0.69–0.85), and 0.79 (95% CI: 0.70–0.86), respectively.ConclusionUltrasonographic measurements of ONSD, PI-ratio, MCAPI and MCAFVd demonstrate a moderate to low weak correlation with ICPi measurements. ICPe is not considered sufficiently precise for noninvasive accurate ICP assessment. The concurrent utilization of CCAU and ONSD measurements may offer superior accuracy for elevated ICP in TBI patients with DC, especially in specificity. Further research is imperative to validate these findings within a more extensive patient population.

Ultrasonographic evaluation of optic nerve sheath diameter in patients severe traumatic brain injury: a comparison with intraparenchymal pressure monitoring.

Increased intracranial pressure (ICP) can worsen the clinical condition of traumatic brain injury (TBI) patients. One non-invasive and easily bedside-performed technique to estimate ICP is ultrasonographic measurement of optic nerve sheath diameter (ONSD). This study aimed to analyze ONSD and correlate it with ICP values obtained by intraparenchymal monitoring to establish the ONSD threshold value for elevated ICP and reference range of ONSD in severe TBI patients. Forty severe TBI patients (Glasgow Coma Scale Score ≤ 8) were included. Ultrasonographic measurement of ONSD was performed and compared with intraparenchymal ICP monitoring to assess their association and determine the ONSD threshold value. Exclusion criteria included individuals under eighteen years old, penetrating TBI, or direct ocular trauma. Fifty-three ONSD measurements were conducted in all patients. The mean ONSD value in the group with intracranial pressure < 20mmHg was 5.4mm ± 1.0, while in the group with intracranial pressure ≥ 20mmHg, it was 6.4mm ± 0.7 (p = 0.0026). A positive and statistically significant correlation, albeit weak (r = 0.33), was observed between ultrasonographic measurement of ONSD and intraparenchymal ICP monitoring. The statistical analysis of the ROC curve identified the best cut-off as 6.18mm, with 77.8% sensitivity and 81.8% specificity. Our results reveal a positive, albeit weak, correlation between ultrasonographic measurement of ONSD and intraparenchymal ICP monitoring, with an ONSD threshold value of 6.18mm. Achieving only 77.8% sensitivity and considering the substantial variability between ONSD measurements (standard deviation at 1.0) might limit the reliability of ICP assessment based solely on ONSD measurements.

Optic Nerve Sheath Meningiomas: A Retrospective Cohort Study Comparing Outcomes in Treated Versus Observed Patients.

The rarity of optic nerve sheath meningiomas (ONSMs) complicates the guidelines surrounding optimal treatment strategies and prognostic factors. There are limited data on the visual outcomes of those treated with radiotherapy versus those observed without treatment. This study aimed to characterize the clinical and radiographic presentations of patients diagnosed with ONSMs and to identify factors predicting improvement in visual function after treatment. This is a retrospective case series of 26 patients who presented to 2 tertiary neuro-ophthalmology practices for 10 years with the presumptive diagnosis of ONSM. Demographic, clinical, investigative, radiologic, treatment, and outcome data were collected. Visual improvement was defined as improvement in visual acuity (VA) by ≥2 Snellen lines or visual field (VF) mean deviation (MD) improvement by ≥2 dB. Statistical analyses were performed to compare patients who experienced improvement in visual function with those who did not poststereotactic radiotherapy to identify pretreatment predictors of visual recovery. Seventeen patients underwent radiotherapy (16 received 54 Gy in 30 fractions and 1 received 50 Gy in 25 fractions) and 4 elected observation. Five were lost to follow-up. Visual function improvement was seen in 10 patients who underwent radiotherapy. Pretreatment VA (logMAR 0.492 vs 1.42, P = 0.025), tumor size (8.50 vs 18.3 mm, P = 0.028), and a decrease in tumor size postradiotherapy (P = 0.009 for VA and 0.035 for VF MD improvement) were significantly associated with objective visual improvement. Pretreatment VA and tumor size may predict improvement in visual function in patients with ONSMs treated with radiotherapy. Future larger scale studies that include these data may be able to draw more definite conclusions.

Real-Time Automated Measurements of Optic Nerve Sheath Diameter for Noninvasive Assessment of Intracranial Pressure in Aneurysmal Subarachnoid Hemorrhage.

Optic nerve sheath diameter (ONSD) is a promising noninvasive parameter for intracranial pressure (ICP) assessment. However, in the setting of aneurysmal subarachnoid hemorrhage (aSAH), several previous studies have reported no association between ultrasonically measured ONSD and ICP. In this study, we evaluate ONSD in patients with aSAH using a novel method of automated real-time ultrasonographic measurements and explore whether factors such as having undergone surgery affects its association to ICP. We prospectively included adult patients with aSAH undergoing invasive ICP monitoring. ONSD was obtained using a prototype ultrasound machine with software for real-time automated measurements at the bedside. Correlation between ONSD and ICP was explored, and the ability of ONSD to discriminate dichotomized ICP was evaluated. Abovementioned analyses were performed for the whole cohort and repeated for subgroups by whether the basal cisterns had been surgically entered before ultrasound examination. Twenty-six ultrasound examinations were performed in 20 patients. There was a positive correlation between ONSD and ICP (R = 0.43; p = 0.03). In the subgroup where the basal cisterns had not been surgicallyentered before ultrasound examination, there was a stronger correlation (R = 0.55; p = 0.01), whereas no correlation was seen in the subgroup where the basal cisterns had beensurgically entered (R = - 0.16; p = 0.70). ONSD displayed an ability to discriminate ICP dichotomized at ≥ 15mm Hg (area under the curve [AUC] = 0.84, 95% confidence interval [CI] 0.65-0.96). Subgroup analysis revealed a perfect discriminatory ability (AUC = 1, 95% CI 0.81-1) where the basal cisterns had not been surgically entered and no discriminatory ability (AUC = 0.47, 95% CI 0.16-0.84) where the basal cisterns had been surgically entered before ultrasound examination. Automatically measured ONSD correlated well with ICPand displayed a perfect discriminatory ability in patients with aSAH in whom the basal cisterns had not been entered surgically before ultrasound examination, and may be a clinically valuable noninvasive marker of ICP in these patients. Caution should be exercised in using ONSD in patients in whom the basal cisterns have been entered surgically before ONSD measurements, as no association was observed in this subgroup.

The Historical and Clinical Foundations of the Modern Neuroscience Intensive Care Unit.

The subspecialty of neurocritical care has grown significantly over the past 40years along with advancements in the medical and surgical management of neurological emergencies. The modern neuroscience intensive care unit (neuro-ICU) is grounded in close collaboration between neurointensivists and neurosurgeons in the management of patients with such conditions as ischemic stroke, aneurysmal subarachnoid hemorrhage, intracerebral hemorrhage, subdural hematomas, and traumatic brain injury. Neuro-ICUs are also capable of specialized monitoring such as serial neurological examinations by trained neuro-ICU nurses; invasive monitoring of intracranial pressure, cerebral oxygenation, and cerebral hemodynamics; cerebral microdialysis; and noninvasive monitoring, including the use of pupillometry, ultrasound monitoring of optic nerve sheath diameters, transcranial Doppler ultrasonography, near-infrared spectroscopy, and continuous electroencephalography. Neuro-ICUs are also capable of specialized neuroprotective management of medical complications, including sodium disorders, renal failure, respiratory failure, and hypertension. These units depend on an interdisciplinary team including speech and language pathologists, occupational and physical therapists, and social workers and case managers, who work to implement early mobilization and successful transition to rehabilitation centers. There are numerous models of neuro-ICUs ranging from "open" units in which patients are cared for in an ICU by an admitting attending, generally without involvement of an intensivist, to "semi-open" units in which intensivists act as consultants, to "closed" units in which the neurointensivist is the admitting attending. The utilization of neuro-ICUs is associated with improved outcomes including lower mortality rates, decreased ICU and hospital length of stay, and improved functional outcomes.

A Case of Myelin Oligodendrocyte Glycoprotein Antibody-Positive Optic Neuritis

Purpose: To report a case of optic neuritis associated with myelin oligodendrocyte glycoprotein (MOG) antibodies, treated with intravenous methylprednisolone pulse therapy.Case summary: A 40-year-old male patient with no underlying disease presented to clinic with sudden onset of bilateral blurry vision that began three days ago. He experienced severe headache and had history of bilateral refractive surgery. Best-corrected visual acuity measured right 0.06 and left 0.04. Relative afferent pupillary defect test was unremarkable, while Ishihara color vision test revealed inability to read any numbers in both eyes, except control plates. Although there were no limitations in extraocular movements, the patient reported pain in both eyes for all gaze movements. Widefield photograph and retinal nerve fiber layer image confirmed swelling of optic nerve head in both eyes. He was treated with high-dose intravenous methylprednisolone (1 g/day for 3 days). Magnetic resonance imaging demonstrated enhancement of the optic nerve sheaths in both eyes, and serum testing indicated positivity for MOG IgG antibodies. Three weeks later, visual acuity in both eyes improved to 1.0, and the color vision test showed correct identification of all 17 plates. Optic nerve head swelling in both eyes had resolved. However, optic neuritis recurred at 4, 6 weeks, and 3 months after the initial treatment, with each episode managed by high-dose intravenous methylprednisolone.Conclusions: This case shows early diagnosis and treatment of MOG antibody-associated optic neuritis can lead to improved visual outcomes. Appropriate serum testing for the diagnosis may be effective in patients with MOG antibody-associated optic neuritis.

Clinical, laboratory, and orbital imaging features of giant cell arteritis in comparison to non-arteritic anterior ischemic optic neuropath: a single center case series.

Giant cell arteritis (GCA) is the most common vasculitis in patients older than 50 years and is considered a "do not miss" diagnosis. However, it remains a diagnostic challenge given overlapping clinical syndromes such as non-arteritic anterior ischemic optic neuropathy (NAION) and poorly explored imaging findings. In this retrospective study between the time period of January 2013 and December 2021, a total of 13 consecutive patients with a pathological diagnosis of GCA and 8 patients with clinical diagnosis of NAION were isolated. Demographic and clinical data for each patient were collected, including pertinent laboratory data. Pertinent physical exam data was also collected, including fundoscopic exam and visual acuity. Two neuroradiologist assessed the orbital MRI imaging findings of GCA and NAION for the presence and characterization of imaging abnormalities. Assessment for potential relationship between GCA orbital findings, laboratory and visual outcomes was performed. Finally, comparison between GCA and NAION imaging findings was performed. 13 GCA patients were assessed. 9 patients had abnormal orbital findings. Of these 8 patients had bilateral orbital involvement The most common imaging findings was perineuritis of the optic nerve sheath, present in 7 patients. In total, 8 NAION patients were assessed. All patients demonstrate optic nerve involvement. The Snellen test was converted to logmar, and visual acuity was assessed for both NAION and GCA for each eye at diagnosis and at the last follow-up. There was no statistical significance for either eye for both GCA and NAION at initial diagnosis and final follow-up. In the 4 GCA patients with normal MRI findings and 9 GCA patients with abnormal MRI findings, there was no statistical significance between initial presentation and final follow-up visual acuity. GCA and NAION are potentially overlapping clinical syndromes with different treatment approach and poorly explored imaging findings. Our case series assesses the orbital imaging findings of both syndromes while noting different imaging pattern of both on MRI, which can serve as a potential tool to aid in diagnosis of both. .

Drive Pressure-Guided Individualized Positive End-Expiratory Pressure in Traumatic Brain Injury Surgery: A Randomized Controlled Trial.

Intraoperative lung-protective ventilation strategies (LPVS) have been shown to improve lung oxygenation and prevent postoperative pulmonary problems in surgical patients. However, the application of positive end-expiratory pressure (PEEP)-based LPVS in emergency traumatic brain injury (TBI) has not been thoroughly explored. The purpose of this study is to evaluate the effects of drive pressure-guided individualized PEEP on perioperative pulmonary oxygenation, postoperative pulmonary complications, and recovery from neurological injury in patients with TBI. A total of 111 TBI patients who met the inclusion criteria at Northern Jiangsu People's Hospital were randomized into three groups: group A (0 PEEP, 50% inhaled oxygen concentration, and 6 mL/kg tidal volume), group B (5 cmH2O PEEP, 50% inhaled oxygen concentration, and 6 mL/kg tidal volume), and group C (individualized PEEP guided by driving pressure, 50% inhaled oxygen concentration, and 6 mL/kg tidal volume). The primary endpoints were lung ultrasound score (LUS), optic nerve sheath diameter (ONSD), and serum levels of neuron-specific enolase (NSE) and High mobility group box 1 protein (HMGB1). Secondary endpoints included intraoperative hemodynamic and respiratory mechanics parameters, postoperative pulmonary complications, and clinical lung infection scores. Eighty-nine patients completed the final analysis. LUS was significantly lower in group C compared to group A at T4 (least square mean [95% confidence interval (CI)]: 2.50 [1.35, 3.65] vs. 5.25 [4.10, 6.40], p < 0.05). Although ONSD increased gradually in group C, it did not differ substantially from group A postoperatively (least square mean [95% CI]: 5.09 [4.90, 5.27] vs 5.16 [4.97, 5.34] mm, p > 0.05). Serum NSE levels in group C were significantly lower on postoperative days 1 (4.40 [3.89, 4.41] vs. 10.95 [10.44, 11.46], p < 0.05) and 3 (2.79 [2.28, 3.30] vs. 10.95 [10.44, 11.46], p < 0.05). Additionally, serum HMGB1 levels in group C were significantly reduced on postoperative days 1 (229 [200, 258] vs. 662 [633, 691], p < 0.05) and 3 (166 [137, 195] vs. 662 [633, 691], p < 0.05). Individualized PEEP guided by driving pressure can improve perioperative pulmonary oxygenation and reduce the incidence of postoperative pulmonary complications. Furthermore, this strategy did not significantly elevate intraoperative intracranial pressure (ICP) and promoted recovery from postoperative neurological injury, likely by reducing the inflammatory response. https://www.chictr.org.cn/ (clinical trial no. ChiCTR2200066795).

Optic nerve sheath enhancement on orbital MRI in giant cell arteritis

BackgroundDifferentiating arteritic anterior ischaemic optic neuropathy (A-AION) due to giant cell arteritis (GCA) from non-arteritic anterior ischaemic optic neuropathy (NA-AION) may pose a diagnostic challenge. Our study aimed to assess...

Mannitol versus mannitol with hypertonic saline for brain relaxation during craniotomies using ultra-sonographic optic nerve sheath diameter

ABSTRACT Background This study compared the effect of conventional doses of mannitol alone versus combined lower doses of mannitol-hypertonic saline on brain debulking during elective craniotomies. Patients and methods Sixty participants aged 18–60 years, ASA class I or II, who were scheduled for elective supratentorial brain tumor surgery, were randomly separated into 2 equal groups. Group (M) received 5 ml/kg of 20% mannitol at the onset of the surgical incision over 15 min. Group (MH) received 2.5 ml/kg of 20% mannitol plus 2.5 ml/kg 3% hypertonic saline (HTS) at the onset of the surgical incision over 15 min. Optic nerve sheath diameter (ONSD), brain relaxation score, serum lactate, electrolytes, and surgeon’s satisfaction were measured. Results Both groups yielded similar results concerning demographic and tumor characteristics. The Optic nerve sheath diameter (ONSD) was considerably lower in group MH compared to group M just before and immediately after dural incision (p = <0.001, and 0.001) respectively. The brain relaxation was considerably more adequate in group MH when compared to group M (p = 0.001). Group MH showed significant elevation in serum sodium, chloride, and osmolarity at 60 min and at the end of surgery with negligible changes at 12- and 24-hrs postoperatively. Moreover, group M showed a significant increase in serum potassium and lactate at 60 min and at the end of surgery, with insignificant change at 12- and 24-hrs postoperatively. Surgeons were more noteworthy satisfied in group MH. Conclusion Optic nerve sheath was comparable to brain relaxation score (BRS) for assessing the brain relaxation. In comparison to mannitol alone, lower prescribed doses of mannitol in combination with hypertonic saline (HTS) have provided better intraoperative brain debulking, clinically accepted electrolyte changes, and more surgeons’ satisfaction during supratentorial brain tumor surgery.

Ultrasonographic measurement of optic nerve sheath diameter during laparoscopic surgeries in pediatric patients: An observational study

Abstract Background and Aims: Laparoscopic surgery involves creation of carbondioxide (CO2) pneumoperitoneum leading to a rise in intracranial pressure (ICP), which can cause expansion of optic nerve sheath diameter(ONSD).We aimed to study the magnitude of changes in ONSD occurring during pediatric laparoscopic surgery and correlate them with changes in end-tidal CO2 (EtCO2), intrabdominal pressure (IAP), and a change in patient position (P). Material and Methods: Thirty-five pediatric patients between 1 and 12 years undergoing laparoscopic surgeries under general anesthesia were included.The ONSD, EtCO2, IAP, and position (P) in degrees from supine were recorded 15 min post-anesthesia induction(T1) and 30 min following the establishment of pneumoperitoneum (T2).The difference between the two groups was analyzed using a paired or unpaired t-test for quantitative variables and using Chi-square or Fisher’s exact test for qualitative data.Correlation between two quantitative variables was performed using Pearson’s correlation coefficient. Results: Mean ONSD showed a significant change (P &lt; 0.001) 30 min (T2) following pneumoperitoneum increasing by an average of 0.04cm as compared to 15 min (T1) post-anesthesia induction (0.57 ± 0.06 vs. 0.61 ± 0.06). There was a moderate to strong positive correlation between change in ONSD and change in EtCO2(correlation coefficient = 0.629, P = 0.001) 30 min post pneumoperitoneum. There was a weak correlation between change in ONSD and change in position (correlation coefficient = 0.276) and a very weak correlation between change in ONSD and change in IAP (correlation coefficient = 0.19). Conclusions: Laparoscopic surgeries in children can cause significant increases in ICP as measured by the ONSD; changes in EtCO2 are the predominant factor responsible. Increasing minute ventilation to maintain normal EtCO2 may help mitigate changes in ICP in children undergoing laparoscopic surgery.

Commentary: Diagnostic Accuracy of Optic Nerve Sheath Diameter Measurement by Ultrasonography for Noninvasive Estimation of Intracranial Hypertension in Traumatic Brain Injury: Systematic Review and Meta-Analysis.

Commentary: Diagnostic Accuracy of Optic Nerve Sheath Diameter Measurement by Ultrasonography for Noninvasive Estimation of Intracranial Hypertension in Traumatic Brain Injury: Systematic Review and Meta-Analysis.

Epidural Blood Patch in Spontaneous Intracranial Hypotension and Role of Optic Nerve Sheath Diameter: A Case Report

AbstractSpontaneous intracranial hypotension (SIH) is caused by spinal leakage of cerebrospinal fluid (CSF) and it is characterized by an orthostatic headache without a history of trauma or dural puncture. Patients may present with headache, there may be low CSF pressure, or imaging evidence of CSF leak. Epidural blood patching (EBP) has been considered as the mainstay of therapy for SIH. We report a case of SIH with bilateral subdural hematoma in a 63-year-old female patient who presented with sudden-onset headache for 4 days without any history of loss of consciousness, vomiting, or seizures. Lumbar EBP was given and it resulted in improved clinical features, imaging findings, and increase in optic nerve sheath diameter (ONSD) when compared with ONSD before EBP administration. EBP produces a tamponade effect and its efficacy results from sealing the dural defect by the injected blood, thus stopping the CSF leak.

The Effects of Antioxidant Cocktail on Ophthalmological Changes Induced by a 60-Day Head-Down Bed Rest in a Randomized Trial.

Neuro-ophthalmological changes have been reported after prolonged exposure to microgravity; however, the pathophysiology remains unclear. Furthermore, several countermeasures have been suggested to counteract the side effects of microgravity. The objectives of the present study were twofold: (1) to assess the neuro-ophthalmological impact of 60 days of head-down bed rest (HDBR) and (2) to determine the potential effects of an antioxidant cocktail. In this case, 20 healthy male subjects completed a 60-day HDBR and were randomly allocated into two groups: a control condition without an antioxidant cocktail (CON) and a condition with an antioxidant cocktail (NUT). The retinal nerve fibre layer thickness (RNFLT) and central retinal thickness (CRT) were assessed with spectral domain optical coherence tomography. The optic nerve sheath diameter (ONSD) was measured by ocular ultrasonography and used to assess indirect changes in the intracranial pressure (ICP). The intraocular pressure (IOP) was assessed by Goldmann applanation tonometry. The CRT tended to be reduced after HDBR. The ONSD was increased at the end and after HDBR. The IOP tended to decrease after HDBR. Finally, the antioxidant cocktail had minor impacts on the ophthalmological changes induced by HDBR. It is worth noting that two participants presented peripapillary edema.