Increase In Optic Nerve Sheath Diameter Research Articles

435 Use of Optic Nerve Sheath Diameter in Extraventricular Drain Weaning in Adults With Post-hemorrhagic Hydrocephalus

INTRODUCTION: Optic nerve sheath diameter (ONSD) can be used as a noninvasive measurement of intercranial pressure. Few studies have evaluated the value of ONSD in predicting the need for ventriculoperitoneal shunt (VPS) placement after development of post-hemorrhagic hydrocephalus (PHH) in adults. METHODS: Adult patients 18 years or older, admitted with intracranial hemorrhage and hydrocephalus requiring EVD placement were included in the study. Demographics were recorded. CT imaging of ONSD was measured (mm) upon initial ED visit before EVD placement (pre-EVD), immediately after successful EVD removal (post-EVD), and if applicable, after EVD removal but immediately before VPS placement. Change in ONSD was calculated and groups were stratified by EVD only patients and EVD+VPS patients. RESULTS: Imaging for 30 patients were successfully retrieved and analyzed for bilateral ONSD values at all timepoints. A statistically significant convergence to a normally distributed mean ONSD was found for both groups (EVD and EVD+VPS). Additionally, a statistically significant increase was found in ONSD between the EVD+VPS group compared to the EVD only group. The EVD only group showed a mean EVD placement time of only 14 days (2 weeks) with an average decrease in ONSD (-0.905mm) compared with the EVD+VPS group who had an increase in ONSD at 14-days (+1.089 mm). CONCLUSIONS: Patients with hydrocephalus due to intracranial hemorrhage who went on to require VPS developed an increase in ONSD despite EVD use while patients who were successfully weaned from the EVD developed a decrease in ONSD. ONSD may be a useful adjunct tool to aid in the process of EVD weaning in this patient population.

Study of the possibilities of non-invasive assessment of increased intracranial pressure according to MRI data on the example of patients with secondary intracranial hypertension

Modern methods of neuroimaging make it possible to develop approaches for assessing intracranial pressure as a replacement for the “gold standard” of invasive monitoring. Aim of the study was to investigate the possibility of using magnetic resonance (MR) characteristics to assess the increase in intracranial pressure in patients with secondary intracranial hypertension. Material and methods. Group 1 – 40 patients with brain tumors, group 2 – 15 patients with communicating hydrocephalus, control group – 36 individuals. The patients underwent MRI with measurement and evaluation of the optic nerve sheath diameter (ONSD), the optochiasmal cistern and the pituitary gland vertical sizes, and tortuosity of the ON. Patients of the 2nd group underwent a phase-contrast MRI with an assessment of the velocity and volumetric characteristics of blood and cerebrospinal fluid flows with the calculation of the intracranial compliance index (ICC). Using the FreeSurfer program, the brain volumes were estimated. Results and discussion. A statistically significant increase in ONSD was found in the groups of patients compared with the control group (by 24 %, p < 0.05), decrease in the vertical size of the pituitary gland and an increase in the vertical size of the optochiasmal cistern (p < 0.05), as well as ICC lowering in group 2 (by 1.7 times, p < 0.05). Tortuosity of ON in group 1 was observed more often than in other groups. A statistically significant positive correlation between ONSD and brain volumes in group 1 (r = 0.55, p < 0.05) and a negative correlation between brain volumes and ICC in group 2 (r = –0.86, p < 0.05) has been found. Conclusions. Based on the presented results, we believe that the combined use of qualitative and quantitative MRI criteria can expand the diagnostic capabilities of non-invasive assessment of increased intracranial pressure.

Interrelation Between Cerebrospinal Fluid Pressure, Intracranial Morphology and Venous Hemodynamics Studied by 4D Flow MRI.

To quantify the effects of CSF pressure alterations on intracranial venous morphology and hemodynamics in idiopathic intracranial hypertension (IIH) and spontaneous intracranial hypotension (SIH) and assess reversibility when the underlying cause is resolved. We prospectively examined venous volume, intracranial venous blood flow and velocity, including optic nerve sheath diameter (ONSD) as anoninvasive surrogate of CSF pressure changes in 11 patients with IIH, 11 age-matched and sex-matched healthy controls and 9 SIH patients, before and after neurosurgical closure of spinal dural leaks. We applied multiparametric MRI including 4D flow MRI, time-of-flight (TOF) and T2-weighted half-Fourier acquisition single-shot turbo-spin echo (HASTE). Sinus volume overlapped between groups at baseline but decreased after treatment of intracranial hypotension (p = 0.067) along with asignificant increase of ONSD (p = 0.003). Blood flow in the middle and dorsal superior sagittal sinus was remarkably lower in patients with higher CSF pressure (i.e., IIH versus controls and SIH after CSF leak closure) but blood flow velocity was comparable cross-sectionally between groups and longitudinally in SIH. We were able to demonstrate the interaction of CSF pressure, venous volumetry, venous hemodynamics and ONSD using multiparametric brain MRI. Closure of CSF leaks in SIH patients resulted in symptoms suggestive of increased intracranial pressure and caused asubsequent decrease of intracranial venous volume and of blood flow within the superior sagittal sinus while ONSD increased. In contrast, blood flow parameters from 4D flow MRI did not discriminate IIH, SIH and controls as hemodynamics at baseline overlapped at most vessel cross-sections.

Retrospective longitudinal assessment of optic nerve sheath diameter in patients with malignant glioma.

Glioblastoma (GBM) is a tumor with rapid growth and a possible relationship to elevated intracranial pressure (ICP). High ICP may not always be associated with clinical signs. A non-invasive technique for assessment of ICP is measuring the optic nerve sheath diameter (ONSD). Identifying patients who need immediate intervention is of importance in neuro-oncological care. The goal of this study is to assess the available magnetic resonance imaging (MRI) of patients with GBM with respect to pre- and postoperative ONSD. Retrospective data analysis was performed on all patients operated for GBM at a tertiary care center between 2010 and 2020. Two pre and one postoperative MRI had to be available. Clinical data and ONSD at multiple time points were analyzed and correlated, as well as preoperative volumetrics. Sixty-seven patients met the inclusion criteria. Clinical signs of elevated ICP were seen in 25.4% (n = 17), while significant perifocal edema was present in 67.2% (n = 45) of patients. Clinical signs of preoperatively elevated ICP were associated with significantly elevated ONSD at diagnosis (p < 0.001) as well as preoperative tumor volume (p < 0.001). Significant perifocal edema at the time of diagnosis was associated with elevated ONSD (p = 0.029) and higher tumor volume (p = 0.003). In patients with significant edema, ONSD increased significantly between preoperative MRIs (p = 0.003/005). In patients with clinical signs of raised ICP, ONSD also increased, whereas it was stable in asymptomatic patients (yes: 5.01+/-4.17 to 5.83+/-0.55 mm, p = 0.010, no: 5.17+/-0.46 mm to 5.38+/-0.41 mm, p = 0.81). A significant increase of ONSD from diagnosis to preoperative MRI and a significant decrease until 3 months postoperatively were observed (p < 0.001). ONSD might help identify high ICP in patients with GBM. In this first-of-its kind study, we observed a significant increase of ONSD preoperatively, likely associated with edema. Postoperatively, ONSD decreased significantly until 3 months after surgery and increased again at 12 months. Further prospective data collection is warranted.

Optic Nerve Sheath Diameter as a Predictor of Raised Intracranial Pressure Findings on Orbital Ultrasound

BACKGROUND&#x0D; Several studies have found an association between raised intracranial pressure (ICP) and optic nerve sheath diameter (ONSD) in conditions with severe head injury and intracranial bleeding. Idiopathic intracranial hypertension is also a cause of elevated ICP. Because the meninges and subarachnoid space around the optic nerve are continuous, a rise in ICP can be detected with an increase in ONSD. The objectives of this study were to correlate Optic Nerve Sheath Diameter (ONSD) with features suggestive of raised intracranial pressure on CT / MRI of the Brain and describe the features suggestive of raised intracranial pressure on CT/MRI Brain in clinically suspected patients.&#x0D; METHODS&#x0D; This was a case control study carried out in the Department of Radio-diagnosis at MGMCRI for suspected raised intracranial pressure evaluation. All these patients were subjected to ultrasound examination of the eye and the optic sheath diameter was measured while the patients were in supine posture. ONSD was measured on Mind ray DC8, and/or GE S7 Expert using High frequency linear probe on the closed upper eyelid with adequate aqueous gel as a coupling agent. ONSD was also measured in Philips 1.5T MRI and Ge optima 128 slice CT. Patients were followed up on whether they were treated surgically or medically and if they developed clinical signs of raised ICP such as headache, vomiting, raised blood pressure, double vision, confusion or loss of consciousness.&#x0D; RESULTS&#x0D; The raised ICP was observed in 30.67 % of study patients and the optic nerve sheath distension was observed in 37.33% of patients. The diagnostic accuracy of determining the optic nerve sheath diameter was equal such as area under curve, sensitivity and specificity as 0.833, 66.67% and 100 % respectively in both methods.&#x0D; CONCLUSIONS&#x0D; ONSD has emerged as an interesting option for measuring intracranial hypertension in brain-injured states, owing to its simplicity, non-invasive nature, and accessibility.

Is optic nerve sheath diameter diagnostic in methanol intoxication?

Background and aimMethyl alcohol intoxication causes severe morbidity and mortality, especially in developing countries. Formic acid is formed as a result of methanol metabolism. Formic acid accumulation and inhibition of adenosine triphosphate synthesis result in ophthalmic issues. This study aimed to demonstrate that the optic nerve sheath diameter (ONSD) measurement is an accurate prognostic marker and can be helpful in the diagnosis of methanol intoxication. Materials and methodsThis prospective study was conducted with 52 patients who were admitted to the emergency department after alcohol consumption and agreed to participate in the study. Age, gender, comorbid diseases, vital signs, ONSD ultrasonography measurements, hospitalization and discharge status, in-hospital mortality status, dialysis need, presence of visual impairment, blood gas parameters, respiratory status, time since alcohol intake, ethanol levels, urea levels, and creatinine levels were analyzed. ResultsROC curve analysis was performed to evaluate the predictive power of ONSD to diagnose methanol intoxication. The area under the curve was 0.857 for the cut-off value of 5.05 mm (95 % CI: 0.728–0.985; p < 0.001), with a sensitivity of 80.8 % and a specificity of 100 %. In the regression analysis performed to determine the prognostic value of the parameters in estimating mortality in methanol intoxication cases, an increase in ONSD (OR: 3.619; 95 % CI: 0.057–0.199; p = 0.001), an increase in lactate levels (OR: 5.653; 95 % CI: 0.040–0.085; p < 0.001), and increased duration after alcohol intake (OR: 2558; 95 % CI: 0.004–0.034; p = 0.014) were identified as independent predictors of mortality, but pH, HCO3, and base deficit levels were not significant predictors. ConclusionsWe believe that ONSD can be helpful for the differential diagnosis and prognosis of patients with suspected methanol toxicity who presented with alcohol intake.

Does prolonged prone position affect intracranial pressure? prospective observational study employing Optic nerve sheath diameter measurements

BackgroundOur aim in this observational prospective study is to determine whether the prone position has an effect on intracranial pressure, by performing ultrasound-guided ONSD (Optic Nerve Sheath Diameter) measurements in patients with acute respiratory distress syndrome (ARDS) ventilated in the prone position.MethodsPatients hospitalized in the intensive care unit with a diagnosis of ARDS who were placed in the prone position for 24 h during their treatment were included in the study. Standardized sedation and neuromuscular blockade were applied to all patients in the prone position. Mechanical ventilation settings were standardized. Demographic data and patients’ pCO2, pO2, PaO2/FiO2, SpO2, right and left ONSD data, and complications were recorded at certain times over 24 h.ResultsThe evaluation of 24-hour prone-position data of patients with ARDS showed no significant increase in ONSD. There was no significant difference in pCO2 values either. PaO2/FiO2 and pO2 values demonstrated significant cumulative increases at all times. Post-prone SPO2 values at the 8th hour and later were significantly higher when compared to baseline (p < 0.001).ConclusionAs a result of this study, it appears that the prone position does not increase intracranial pressure during the first 24 h and can be safely utilized, given the administration of appropriate sedation, neuromuscular blockade, and mechanical ventilation strategy. ONSD measurements may increase the safety of monitoring in patients ventilated in the prone position.

The role of repeated brain computed tomography based on ultrasound monitoring of optic nerve sheath diameter after moderate traumatic brain injury.

This study was conducted to evaluate the association between changes in repeated brain computed tomography (CT) findings and the optic nerve sheath diameter (ONSD) determined by ocular ultrasonography in patients with moderate blunt traumatic brain injury (TBI). This cross-sectional study was performed on patients with moderate blunt TBI (Glasgow Coma Scale, 9-12) who were referred to the emergency department during a 1-year period. Initially, all patients underwent a brain CT scan and primary ocular ultrasonography. Patients who were candidates for a second brain CT scan under observation in the emergency department also underwent a second ocular ultrasound. The primary outcome was the progression of brain lesions on repeated brain CT scans. Logistic regression and the area under receiver operating characteristic curve (AUC) were used. Overall, 204 patients with a mean age of 43±13.4 years were enrolled in the study. The study detected expanding changes in brain CT scans from 29 patients (14.2%). The progression of lesion on CT scan were significantly associated with changes in the Glasgow Coma Scale. In the second brain CT scan, there were significant associations between the progression of lesion on CT scan and the increased size of the ONSD measured on both axial and coronal sections (odds ratio, 17.3-47.5; AUC, 0.88-0.93). Among patients with moderate TBI, an increase in ONSD on ocular ultrasound seems to be an appropriate criterion for repeating a brain CT scan to select a suitable therapeutic intervention.

Optic Nerve Sheath Diameter Affected by Cervical Collar Placement in Minor Head Trauma Patients

Background: Head trauma may cause an increase in intracranial pressure (ICP). The use of ocular ultrasound to measure optic nerve sheath diameter (ONSD) is a method to determine the ICP. The use of the rigid cervical collar in head trauma patients contribute to elevating ICP, and therefore, potentially causing further deterioration in their condition. Objectives: This study aimed to describe changes in ONSD after the placement of a c-collar and analyze these changes depending on the time in the c-collar. Methods: This prospective study measured the ONSD of minor head trauma patients before and after the placement of a c-collar. Patients aged ³18 with blunt head trauma and Glasgow Coma Score ³13 were included in the study. Each eye was scanned twice. This was done before c-collar placement, at 5 and 20 min after placement. The mean values of both eyes were calculated and analyzed. Results: This study investigated 50 patients. The mean baseline ONSD was obtained at 4.71mm±0.22 (4.54-4.77). Furthermore, T5 and T20 measurements were 5.19±0.41 (5.07-5.31) and 5.26±0.45 (5.14-5.39), respectively. The ONSD increased at T5 and T20. The changes from the baseline measurements were statistically significant (P=0.000, P=0.000). The difference between T5 and T20 groups was an increase in ONSD, and these differences were also statistically significant (0.07±0.19; P=0.008). Conclusion: Our results revealed that minor head trauma patients using a c-collar may increase ONSD by timeline the clinical effects of which have to be determined with further studies. Enlargement in ONSD should be considered when interpreting ICP.

The value of the optic nerve sheath diameter measured using computerized brain tomography in the evaluation of mortality status in patients admitted to the emergency department with intracranial hemorrhage

Background/Aim: The optic nerve sheath diameter (ONSD) measurement is a non-invasive method that can be obtained from computerized tomography (CT) images. It can therefore be a useful diagnostic tool in determining prognosis in the emergency department. The aim of this study was to investigate the relationship between ONSD and mortality status in patients with intracranial hemorrhage who presented to the emergency department by measuring ONSD on computerized brain tomography images taken during admission. Methods: This retrospective cohort study was carried out in the emergency department of a tertiary hospital between December 1, 2018 and December 1, 2020 and included intracranial hemorrhage patients and patients with normal brain CT scans that had been obtained for any reason. Bilateral ONSDs were measured in both the intracranial hemorrhage and control groups. We first evaluated whether ONSD would differ between the two groups after which the relationship between ONSD and mortality was analyzed in the patient group who presented with bleeding. Results: Intracranial hemorrhage was present in half the cases and midline shift in 21.5%. A statistically significant increase in ONSD was observed in cases with intracranial hemorrhage (P &lt; 0.001). Similarly, a statistically significant increase in ONSD was found in cases with midline shifts and mortality (P &lt; 0.001). A cut-off value of 4.19 mm for mean optic nerve diameter exhibited 100% sensitivity and 70% specificity in terms of hemorrhage detection (area under the curve [AUC]: 0.952; P &lt; 0.001). A cut-off value of 6.03 mm for ONSD exhibited 76% sensitivity and 74% specificity in terms of hemorrhage detection (AUC: 0.730; P = 0.001). The odds ratio for prediction of mortality based on a regression analysis was 8.838 in cases with intracranial hemorrhage (P &lt; 0.001). Conclusion: ONSSD measured on CT images is a promising tool for prediction of intracranial hemorrhage, midline shift, and mortality status.

Comparison of the Effects of Propofol and Sevoflurane Anesthesia on Optic Nerve Sheath Diameter in Robot-Assisted Laparoscopic Gynecology Surgery: A Randomized Controlled Trial.

Optic nerve sheath diameter (ONSD) is used as a surrogate parameter for intracranial pressure. This study was conducted to evaluate the effect of the anesthetics (sevoflurane and propofol) on ONSD in women undergoing robotic surgery. The 42 patients who were scheduled for robot-assisted gynecology surgery were randomly allocated to the sevoflurane group or the propofol group. ONSD was recorded at 10 min after the induction of anesthesia (T0); 5 min, 20 min, and 40 min after carbon dioxide pneumoperitoneum was induced and the patients were put in a steep Trendelenburg position (T1, T2, and T3, respectively); and at skin closure after desufflation of the pneumoperitoneum (T4). Patients were observed for postoperative nausea and vomiting (PONV) during the immediate postoperative period. The propofol group had significantly lower ONSD than the sevoflurane group at T3. Mean ONSD values continuously increased from T0 to T3 in both groups. Two patients in the sevoflurane group experienced PONV. This study suggests that propofol anesthesia caused a lower increase in ONSD than sevoflurane anesthesia.

Evaluation of intra-cranial pressure changes by measuring the optic nerve sheath diameter during the lung recruitment maneuver in patients with acute respiratory distress syndrome: A prospective study.

The lung recruitment maneuver (LRM) applied in acute respiratory distress syndrome (ARDS) may increase the intra-cranial pressure (ICP). This study evaluated the effect of LRM on intra-cranial pressure changes in patients with ARDS by measuring the optic nerve sheath diameter (ONSD). LRM was applied to patients undergoing follow-up for ARDS, with a positive pressure of 30 cmH2O for 30 s. ONSD on ultra-sonography, dynamic lung compliance (Cdyn), oxygen saturation (SpO2), and hemodynamic parameters were measured before (T0), immediately after (T1), and 10 min after (T2) LRM. The primary endpoint was the effect of LRM on ONSD changes. The secondary endpoints included the effect of LRM on Cdyn, SpO2 change, and relationship between Cdyn and ONSD changes. The study included 60 patients. ONSD was higher at T1 than at T0 (median [interquartile range]: 5.13 [0.4] vs. 5.3 [0.3] mm, P < 0.001) but was similar at T0 and T2 (5.13 [0.4] vs. 5.09 [0.37] mm, P = 0.36). Cdyn and SpO2 were significantly higher at T1 and T2 than at T0 (Cdyn: 22.3 [5.8] vs. 23.7 [7.5] vs. 19.4 [6.6] mL/cmH2O, P < 0.001; SpO2: 90[2] vs. 92[4] vs. 88[4] %, P = 0.013). A significant correlation existed between Cdyn and ONSD changes, which increased at T2 compared to T0 (P < 0.001). LRM applied in ARDS causes a short-term increase in ONSD. However, Cdyn increases 10 min after LRM and causes ONSD, thereby leading to a decrease in ICP.

The Effect of Different Posture on Normal Saline Injection in Optic Nerve Sheath Diameter in Thoracic Epidural Anesthesia

BACKGROUND Thoracolumbar or caudal epidural anesthesia affects intracranial pressure (ICP) in both animals and humans. Epidural injection increases ICP at least transiently. Measurement of the optic nerve sheath diameter (ONSD) using ultrasonography is one of the noninvasive methods for ICP assessment. OBJECTIVES The purpose of this study was to investigate the effect of the different posture during epidural saline injection to the ONSD under awake conditions. STUDY DESIGN Prospective, randomized trial. SETTING An interventional pain management practice in South Korea. METHODS This study included 44 patients receiving thoracic epidural catheterization for pain management after upper abdominal or thoracic surgery. Following successful epidural space confirmation, patients were randomized to receive epidural saline while supine (A group) or in sitting position (B group), respectively. Transorbital sonography was performed for the measurement of the ONSD, and the ONSD was measured at 3 mm posterior to the optic nerve head. RESULTS Both A and B groups showed significant increases of ONSD according to time. Mean ONSD values measured at T10, T20, and T40 significantly increased from the baseline value (T0) (*P < 0.05 vs. T0, †P < 0.001 vs. T0, ‡P < 0.005 vs. T0). The mean ONSD values measured at any of the time points and degrees of changes (T10-T0, T20-T0, and T40-T0) between groups A and B did not show any significant changes. LIMITATIONS Epidural pressure and ONSD measurement can make this study more reliable. Further study showing changes of epidural pressure with ONSD measurement is required. CONCLUSIONS Thoracic epidural injection of 10 mL of normal saline resulted in a significant increase of ONSD compared with the baseline. However, the different posture did not affect the increase of ONSD.

The Contribution of Measuring the Optic Nerve Sheath Diameter by using Ultrasonography to the Diagnosis and Monitoring of Intracranial Hypertension

Background: Intracranial hypertension, which may have a number of different causes, is a medical emergency. Although difficult to identify due to non-specific symptoms, it must be treated appropriately. An early sign of intracranial hypertension is an increase is observed in the optic nerve sheath diameter. . Ultrasonography is a rapid and easy-to-apply method to detect an increase in optic nerve sheath diameter, and may be useful for the emergency diagnosis and treatment, as well as contributing to clinical follow-up. Case Presentation: In the present study, seven patients with clinical suspicion for rapid intracranial pressure were admitted. Clinical scenarios included traffic accident, metabolic imbalance, infection, and intracranial mass. The pediatric emergency specialist performed optic nerve sheath measurement by using ultrasonography and a dilatation was detected. All measurements were taken by the certified and experienced pediatric emergency specialist blinded to the patient's clinical state and also the specialist was under observation of a lecturer during the measurements. Except for one patient, the control optic sheath diameter measurements were performed in the period, when they had no complaint, and the values were determined to be normal. To our knowledge, this case series is the first one examined in Turkey. The data from cases was collected between 2015 and 2016. Conclusion: Optic nerve sheath diameter measurement is a non-invasive method that offers ease of diagnosis and follow-up of suspected intracranial hypertension.

Evaluation of the effect of the mouth gag use on optic nerve sheath diameter of pediatric patients undergoing tonsillectomy or Adenotonsillectomy: An observational study

BackgroundA mouth gag is usually used during tonsillectomy and adenotonsillectomy surgeries, cleft palate repair, obstructive sleep apnea surgery, and intraoral tumor excision. The placement of the gag causes hemodynamic changes similar to laryngoscopy. The aim of this study was to evaluate the effect of mouth gag placement on the optic nerve sheath diameter (ONSD) of pediatric patients. The secondary aim was to assess the relationship between neck extension and changes in ONSD.MethodsThe trial was prospectively registered to the Australian New Zealand Clinical Trials Registry (Trial ID: ACTRN12618000551291) on 12.04.2018. This prospective, observational study was performed in a tertiary university hospital operating room between 01.05.2018–01.07.2018. Thirty-five children aged < 18 years, with ASA I status, who were scheduled for tonsillectomy and adenotonsillectomy surgeries were prospectively included in the study. Measurements of ONSD were performed (T0) after induction of anesthesia, (T1) after endotracheal intubation, (T2) after mouth gag placement, and (T3) 20 min after mouth gag placement. After the mouth gag was placed and the head was positioned for surgery, the degree of neck extension was calculated.ResultsAll participants completed the study. There were significant differences in ONSD values at time points T1, T2, and T3 (p < 0.001, CI: − 0.09,-0.05; p < 0.001, CI: − 0.09,-0.05; p < 0.001, CI: − 0.05,-0.02; respectively). The maximum increase in ONSD was after intubation (0.69 ± 0.06 mm) and immediately after mouth gag placement (0.67 ± 0.07 mm). ONSD values continued to increase 20 min after gag placement (0.36 ± 0.04). There was no relation between the degree of neck extension and ONSD values (β = 0.63, p = 0.715).ConclusionsThe use of a mouth gag causes significant increases in ONSD measurements of children. Therefore, attention to the duration of mouth gag placement should be considered during surgery.Trial registrationThe trial was prospectively registered to the Australian New Zealand Clinical Trials Registry (Trial ID: ACTRN12618000551291) on 12.04.2018.

Ultrasonographic measurement of the optic nerve sheath diameter in dysthyroid optic neuropathy.

The aim of this study is to evaluate the optic nerve sheath diameter (ONSD) in eyes with dysthyroid optic neuropathy (DON) and its relationship with clinical characteristics and disease severity. Patients diagnosed as thyroid-associated ophthalmopathy (TAO), with or without DON, and healthy participants were recruited. Vertical and horizontal sectional images of the optic nerve were collected by B-scan ultrasonography. ONSDs at 3 mm and 6 mm behind the eyeball were measured independently by two researchers. Multivariate regression analysis was performed to evaluate the association of ONSD with demographic and ocular parameters in TAO patients. Areas under the receiver operating characteristic curves (AUROCs) were applied to evaluate the diagnostic accuracy of ONSD for DON. A total of 47 healthy eyes, 36 TAO eyes without DON, and 33 eyes with DON were studied. ONSDs at 3 mm and 6 mm of DON eyes were significantly higher than those in non-DON and healthy eyes (all P < 0.05). There was no significant difference in ONSDs between clinically active and inactive eyes (both P > 0.05). DON occurrence showed a positive association with both ONSDs at 3 mm (β = 0.49, 95% CI: 0.14-0.83, P = 0.007) and 6 mm (β = 0.58, 95% CI: 0.20-0.96, P = 0.003). ONSDs at 3 mm and 6 mm showed a desirable diagnostic capacity to distinguish DON from non-DON eyes (AUROC was 0.77 and 0.75, respectively). An increase in ONSD is evident in DON eyes independent of clinical activity. Ultrasound-based ONSD has sufficient ability to distinguish DON from non-DON eyes.

Correlation of optic nerve and optic nerve sheath diameter with intracranial pressure in pigs.

Several studies have shown an association between intracranial pressure and the diameter of the optic nerve sheath measured by transbulbar ultrasonography. To understand the pathophysiology of this phenomenon, we aimed to measure the changes of the optic nerve, optic nerve sheath and perineural space separately with increasing intracranial pressure in a porcine model. An external ventricular drain was placed into the third ventricle through a right paramedian burrhole in eight anesthesized pigs. The diameters of the optic nerve and the optic nerve sheath were measured while the intracranial pressure (ICP) was increased in steps of 10mmHg from baseline up to 60 mmHg. The median diameters of the optic nerve (ON) increased from 0.36 cm (baseline- 95% confidence interval (CI) 0.33 cm to 0.45 cm) to 0.68 cm (95% CI 0.57 cm to 0.82 cm) at ICP of 60 mmHg (p<0.0001) and optic nerve sheath (ONS) from 0.88 cm (95% CI 0.79 cm to 0.98 cm) to 1.24 cm (95% CI 1.02 cm to 1.38 cm) (p< 0.002) while the median diameter of the perineural space (PNS) (baseline diameter 95% CI 0.40 cm to 0.59 cm to diameters at ICP 60 95% CI 0.38 cm to 0.62 cm) did not change significantly (p = 0.399). Multiple comparisons allowed differentiation between baseline and values ≥40 mmHg for ON (p = 0.017) and between baseline and values ≥ 50mmHg for ONS (p = 0.006). A linear correlation between ON (R2 = 0.513, p<0.0001) and ONS (R2 = 0.364, p<0.0001) with ICP was found. The median coefficient of variation for intra- and inter-investigator variability was 8% respectively 2.3%. Unexpectedly, the increase in ONS diameter with increasing ICP is exclusively related to the increase of the diameter of the ON. Further studies should explore the reasons for this behaviour.

Optic Nerve Sheath Diameter Ultrasound: Optic Nerve Growth Curve and Its Application to Detect Intracranial Hypertension in Children

First, to create an optic nerve growth curve from normal optic nerve sheath diameter (ONSD) values measured by using B-scan ultrasonography in subjects 0-18 years of age. Second, to identify age-appropriate cutoff values of ONSD to be used in the diagnosis of intracranial hypertension (IHT). Prospective cross-sectional study. B-scan ocular ultrasonography was performed on both eyes of 215 subjects 0-18 years of age, divided into 3groups: 165 healthy children, 29 children with IHT (all>4 years of age), and 21 children with optic disc drusen (ODD). There were no statistically significant differences in between the ONSDs of healthy children and those in subjects with ODD. An optic nerve growth curve was created by using ONSDs measured in healthy subjects 0-18 years of age, using the equation: ONSD= ln [33.15] - (-0.18× ln [children's age]). The curve showed a progressive increase of ONSD up to 10 years of age, and it remained constant until the age of 18. For this reason, 2 different cutoff values were calculated for age groups 4-10 and 11-18. Values were 4.10mm and 4.4mm, respectively, with a 100.0% sensitivity and a specificity ranging from 83.9% to 98.8%. A sensitivity of 28.6% was reached for the population of subjects 4-18 years of age with a threshold value of 5mm, as used in published reports. The ONSD continued to enlarge gradually until the age of 10. Therefore, 2 different cutoff values for the age groups 4-10 and 11-18 were calculated, considering the ONSDs of subjects 11-18 years of age overlapping with those of adults. No patients with IHT <4 years old were found. Further studies are needed to evaluate the correct cutoff values for these ages.

The Effect of Speed of Normal Saline Injection on Optic Nerve Sheath Diameter in Thoracic Epidural Anesthesia

Background: Intracranial pressure (ICP) is affected after epidural saline solution or local anesthetic injection. Both ICP and epidural pressures have been shown to reach peak pressure just after epidural injection and begin decline thereafter. Measuring the optic nerve sheath diameter (ONSD) through ultrasonography is one of the noninvasive methods used for ICP assessment. Objectives: The purpose of this study was to investigate the effect of the speed of epidural saline injection on the ONSD under awake conditions. Study Design: Prospective randomized trial. Setting: An interventional pain management practice in South Korea. Methods: This study included 40 patients receiving thoracic epidural catheterization for pain management after upper abdominal or thoracic surgery. Following successful epidural space confirmation, patients were randomized to receive epidural saline infusion with a speed of either 1 mL/second (slow speed, A group) or 3 mL/second (rapid speed, B group), respectively. For the measurement of ONSD, transorbital sonography was performed and ONSD was measured at 3 mm posterior to the optic nerve head. Results: The A and B groups showed significant increases in ONSD according to time. Post hoc analysis of this result revealed that ONSD at T10 and T30 were significantly increased from baseline values (T0) (*P &lt; 0.05 vs. T0; +P &lt; 0.001 vs. T0). The mean values at any of the time points and degree of changes (T1-T0, T10-T0, and T30-T0) in ONSD between groups A and B did not show any significance. Limitations: We could not confirm the time of normalization of ONSD after the end of epidural injection of normal saline. Conclusions: Thoracic epidural injection of 10 mL of normal saline solution resulted in a significant increase of ONSD compared to baseline, however, the speed of injection did not affect the increase of ONSD. Key words: Epidural, saline, optic nerve, diameter

Effects of pneumoperitoneum and steep Trendelenburg position on cerebral hemodynamics during robotic-assisted laparoscopic radical prostatectomy

Background:We evaluated the relationship between ultrasonographical acquired parameters and short-term postoperative cognitive function in patients undergoing robotic-assisted radical prostatectomy (RALP).Methods:Ninety elderly patients scheduled for RALP had their optic nerve sheath diameter (ONSD), the cross-sectional area (CSA) of the internal jugular vein (IJV) and the IJV valve (IJVV) competency assessed by ultrasound. The patients were analyzed in 2 groups based on whether displayed IJVV incompetency (IJVVI). The 3 parameters were measured before anesthesia (T0), immediately after induction of general anesthesia (T1), 5 minutes after establishing pneumoperitoneum (T2), 5 minutes after placing the patient in the Trendelenburg position (T3), and 5 minutes after the release of the pneumoperitoneum in the supine position (T4). Regional cerebral tissue oxygen saturation (rSO2) was also measured by near-infrared spectroscopy intraoperatively. The Mini-Mental State Examination (MMSE) and Confusion Assessment Method (CAM) were performed the day before surgery and on postoperative days 1, 3, and 7.Results:We found that 52% of patients had evidence of IJVVI after being placed in the Trendelenburg position after pneumoperitoneum was established (T4). Patient with IJVVI showed a significant increase of ONSD and CSA at T1, T2, T3, T4 but there was no associated decrease in rSO2. MMSE scores were reduced at postoperative day 1 and the 7 patients that developed postoperative delirium came from Group IJVVI.Conclusions:Our observations suggest that elderly patients that show IJVVI after adequate positioning for RALP may develop elevated intracranial pressure as well as mildly compromised postoperative cognitive function in the short term.