Optic Nerve Sheath Diameter Values Research Articles

An Acute Bout of Subconcussive Head Impacts Does Not Change Intracranial Pressure

Purpose: Subconcussive head impacts (SHI) are known to cause a variety of negative sequelae including increased plasma concentrations of neuronal structural and glial proteins, attenuated neurovascular coupling, and impaired vestibular function. Traumatic brain injuries are associated with an increase in intracranial pressure (ICP). However, it is unknown whether an acute bout of SHI increases ICP. We tested the hypothesis that estimates of ICP via ultrasound assessments of optic nerve sheath diameter (ONSD) would be greater following a single session of repetitive SHI versus a control condition. Methods: 14 healthy participants (age: 19±2 y; BMI: 21±4 kg/m2, 3 women) with at least 3 y of soccer heading experience completed two experimental conditions in a randomized crossover design. 20 soccer headings were used to induce repetitive SHI and 20 soccer kicks were used as the control condition. A soccer ball was projected from a soccer JUGS machine (40 km/h, 12.2 m away) every 30 s for both conditions. ONSD assessed via ultrasound is associated with direct measures of ICP. Subjects were in the supine position during ONSD (transverse plane, each eye; B-mode linear array ultrasound), heart rate (HR; 3-lead ECG), and mean arterial blood pressure (MAP; photoplethysmography) measurements conducted at baseline prior to heading/kicking and at 2 h, 24 h, and 72 h post. ONSDs were measured 3 mm under the bulb in triplicate for each eye and the mean values were used for analyses. Inter-eye ONSD values were also averaged for analyses. Clinical intervention to alleviate elevated ICP is indicated when ONSD is > 5.0 mm. Data were analyzed using a mixed-effects model with repeated measures with time and condition as within subject factors. Data are presented as mean ± SD if statistically significant. Results: No subjects had an ONSD > 5.0 mm in either eye following heading or kicking. Left ONSD was greater than baseline at 2 h post heading (2.89 ± 0.25 mm vs. 2.99 ± 0.27 mm; p = 0.0157) and greater than baseline at 2 h (2.92 ± 0.37 mm vs. 2.98 ± 0.31 mm; p = 0.0352) and 72 h (3.08 ± 0.26 mm; p = 0.0067) post kicking. Left ONSD at 72 h post kicking was greater than heading (3.08 ± 0.26 mm vs. 2.93 ± 0.25 mm; p = 0.0022). There were no interaction effects for right ONSD (p = 0.4686), average ONSD (p = 0.1178), HR (p = 0.1039) or MAP (p = 0.3889). Conclusion: Neither the heading nor kicking intervention elicited a clinically relevant ONSD that would require medical attention. Contrary to our hypothesis, an acute bout of 20 soccer headers did not evoke greater ONSD in healthy subjects versus kicking. Therefore, our data indicate that a single session of SHI does not increase ICP. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effect of different positive end expiratory pressure levels on optic nerve sheath diameter in patients with or without midline shift who are undergoing supratentorial craniotomy

PurposeIn general, high levels of PEEP application is avoided in patients undergoing craniotomy to prevent a rise in ICP. But that approach would increase the risk of secondary brain injury especially in hypoxemic patients. Because the optic nerve sheath is distensible, a rise in ICP is associated with an increase in the optic nerve sheath diameter (ONSD). The cutoff value for elevated ICP assessed by ONSD is between 5.6 and 6.3 mm. We aimed to evaluate the effect of different PEEP levels on ONSD and compare the effect of different PEEP levels in patients with and without intracranial midline shift.MethodsThis prospective observational study was performed in aged 18–70 years, ASA I–III, 80 patients who were undergoing supratentorial craniotomy. After the induction of general anesthesia, the ONSD’s were measured by the linear transducer from 3 mm below the globe at PEEP values of 0–5–10 cmH2O. The ONSD were compered between patients with (n = 7) and without midline shift (n = 73) at different PEEP values.ResultsThe increases in ONSD due to increase in PEEP level were determined (p < 0.001). No difference was found in the comparison of ONSD between patients with and without midline shift in different PEEP values (p = 0.329, 0.535, 0.410 respectively). But application of 10 cmH2O PEEP in patients with a midline shift increased the mean ONSD value to 5.73 mm. This value is roughly 0.1 mm higher than the lower limit of the ONSD cutoff value.ConclusionsThe ONSD in adults undergoing supratentorial tumor craniotomy, PEEP values up to 5 cmH2O, appears not to be associated with an ICP increase; however, the ONSD exceeded the cutoff for increased ICP when a PEEP of 10 cmH2O was applied in patients with midline shift.

Prediction of Intracranial Pressure in Patients with an Aneurysmal Subarachnoid Hemorrhage Using Optic Nerve Sheath Diameter via Explainable Predictive Modeling.

Background: The objective of this investigation was to formulate a model for predicting intracranial pressure (ICP) by utilizing optic nerve sheath diameter (ONSD) during endovascular treatment for an aneurysmal subarachnoid hemorrhage (aSAH), incorporating explainable predictive modeling. Methods: ONSD measurements were conducted using a handheld ultrasonography device during the course of endovascular treatment (n = 126, mean age 58.82 ± 14.86 years, and female ratio 67.46%). The optimal ONSD threshold associated with an increased ICP was determined. Additionally, the association between ONSD and ICP was validated through the application of a linear regression machine learning model. The correlation between ICP and various factors was explored through the modeling. Results: With an ICP threshold set at 20 cmH2O, 82 patients manifested an increased ICP, with a corresponding ONSD of 0.545 ± 0.08 cm. Similarly, with an ICP threshold set at 25 cmH2O, 44 patients demonstrated an increased ICP, with a cutoff ONSD of 0.553 cm. Conclusions: We revealed a robust correlation between ICP and ONSD. ONSD exhibited a significant association and demonstrated potential as a predictor of ICP in patients with an ICP ≥ 25 cmH2O. The findings suggest its potential as a valuable index in clinical practice, proposing a reference value of ONSD for increased ICP in the institution.

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.

High myopia at high altitudes.

Background: Optic nerve sheath diameter (ONSD) increases significantly at high altitudes, and is associated with the presence and severity of acute mountain sickness (AMS). Exposure to hypobaria, hypoxia, and coldness when hiking also impacts intraocular pressure (IOP). To date, little is known about ocular physiological responses in trekkers with myopia at high altitudes. This study aimed to determine changes in the ONSD and IOP between participants with and without high myopia (HM) during hiking and to test whether these changes could predict symptoms of AMS. Methods: Nine participants with HM and 18 without HM participated in a 3-day trek of Xue Mountain. The ONSD, IOP, and questionnaires were examined before and during the trek of Xue Mountain. Results: The ONSD values increased significantly in both HM (p = 0.005) and non-HM trekkers (p = 0.018) at an altitude of 1,700m. In the HM group, IOP levels were greater than those in the non-HM group (p = 0.034) on the first day of trekking (altitude: 3,150m). No statistically significant difference was observed between the two groups for the values of ONSD. Fractional changes in ONSD at an altitude of 1,700m were related to the development of AMS (r pb = 0.448, p = 0.019) and the presence of headache symptoms (r pb = 0.542, p = 0.004). The area under the ROC curve for the diagnostic performance of ONSD fractional changes at an altitude of 1,700m was 0.859 for predicting the development of AMS and 0.803 for predicting the presence of headache symptoms. Conclusion: Analysis of changes in ONSD at moderate altitude could predict AMS symptoms before an ascent to high altitude. Myopia may impact physiological accommodation at high altitudes, and HM trekkers potentially demonstrate suboptimal regulation of aqueous humor in such environments.

Characterization of Ocular Sonography Findings and their Relationship to Clinical Features from a South Indian Cohort of Idiopathic Intracranial Hypertension.

Idiopathic intracranial hypertension (IIH) typically manifests with headache, accompanied by papilledema and visual loss, and has a higher prevalence in females. In recent years, ocular sonography, particularly, measurement of optic nerve sheath diameter (ONSD), is being investigated for diagnosis of IIH. A total of 35 patients over the age of 18 years, fulfilling the modified Dandy's criteria for diagnosis of IIH were included. Patients underwent assessment with magnetic resonance imaging, lumbar puncture, and ocular sonography to measure ONSD and ocular arterial indices. The mean ONSD values (in centimeters) in the right eye of patients with IIH was 0.57 ± 0.13, while it was 0.48 ± 0.03 in controls. In the left eye, the mean ONSD value (cm) was 0.59 ± 0.13 in patients with IIH and 0.48 ± 0.03 in controls. ONSD was significantly higher in cases compared to controls (P < 0.001, Welch test). Pulsatility index of the central retinal artery was significantly higher in cases compared to controls (P < 0.001, Welch test). Resistance index of the ophthalmic artery was statistically significant (P < 0.005, Welch test). Receiver operating characteristic curve analysis revealed a cutoff value of 5.1 mm on the right side and 5 mm on the left side had a sensitivity and specificity of more than 80% for IIH diagnosis. Our study provides insights into the utility of optic nerve sheath measurements and arterial indices in the diagnosis of IIH in a South Indian cohort. Further research is needed to fully understand the longitudinal relationship of these parameters and treatment outcomes in IIH.

Bedside ultrasonographic evaluation of optic nerve sheath diameter for monitoring of intracranial pressure in traumatic brain injury patients: a cross sectional study in level II trauma care center in India.

Optic nerve sheath diameter (ONSD) is an emerging non-invasive, easily accessible, and possibly useful measurement for evaluating changes in intracranial pressure (ICP). The utilization of bedside ultrasonography (USG) to measure ONSD has garnered increased attention due to its portability, real-time capability, and lack of ionizing radiation. The primary aim of the study was to assess whether bedside USG-guided ONSD measurement can reliably predict increased ICP in traumatic brain injury (TBI) patients. A total of 95 patients admitted to the trauma intensive care unit was included in this cross sectional study. Patient brain computed tomography (CT) scans and Glasgow Coma Scale (GCS) scores were assessed at the time of admission. Bedside USG-guided binocular ONSD was measured and the mean ONSD was noted. Microsoft Excel was used for statistical analysis. Patients with low GCS had higher mean ONSD values (6.4±1.0 mm). A highly significant association was found among the GCS, CT results, and ONSD measurements (P<0.001). Compared to CT scans, the bedside USG ONSD had 86.42% sensitivity and 64.29% specificity for detecting elevated ICP. The positive predictive value of ONSD to identify elevated ICP was 93.33%, and its negative predictive value was 45.00%. ONSD measurement accuracy was 83.16%. Increased ICP can be accurately predicted by bedside USG measurement of ONSD and can be a valuable adjunctive tool in the management of TBI patients.

Optical coherence tomography and shear wave elastography findings in Graves ophthalmopathy.

The main feature of Graves ophthalmopathy (GO) is revealed by determining the activity and severity of the disease. We aimed to evaluate the use of imaging methods can also provide additional information about the severity of this disease. Optical coherence tomography (OCT) and shear wave elastography (SWE) findings were compared in 32 patients with mild GO group and in the healthy control group. Measuring for TSH receptor antibody (TRAb) serum level is used third-generation assay. In Graves group, optic nerve sheath diameter (ONSD) values were increased in both eyes (p < 0.001, p < 0.001). SWE measurements showed a significant increase both eye optic nerve (ON) and right eye soft tissue elasticity values in GO group (p < 0.001, p < 0.001, p < 0.001, respectively). There was a significant thinning in left temporal retinal nerve fiber layer (RNFL) thickness and left RNFL peripapillary thickness in GO group (p < 0.001, p < 0.025, respectively). There was a correlation between left eye OCT and SWE findings. Also, there was a significant difference between the median left eye ON and soft tissue elasticity results in the TRAb-positive GO group (p = 0.049, p = 0.048, respectively). SWE measurements showed a significant increase both eyes ONSD, ON and right eye soft tissue elasticity values in GO group. GO group was significant thinning in some left eye regions in OCT measurements. There was a correlation between left eye OCT and SWE findings. In addition to clinical activity score and TRAb, SWE and OCT can be used to monitor in patients with GO.

Transcranial ultrasonographic evaluation of effect of ventriculoperitoneal shunt on intracranial dynamics: A prospective observational study

BackgroundTranscranial sonographic (TCS) evaluation of optic nerve sheath diameter (ONSD), third ventricular diameter (TVD) and mean flow velocities (Vm) and pulsatility index (PI) of middle cerebral artery (MCA) can provide important insights to the change in intracranial dynamics following ventriculo-peritoneal (VP) shunt surgery. The primary objective of this study was to observe changes in ONSD values following VP shunt at 12 h, compared to pre-VP shunt values. MethodsAfter obtaining ethical approval, patients admitted with a diagnosis of hydrocephalus posted for a VP shunt surgery were prospectively enrolled. TCS evaluation was done before induction of anesthesia and 12-hour post-VP shunt surgery. We recorded the values of ONSD, TVD and Vm and PI MCA at both time points. ResultsThirty-four patients (19 male) were evaluated for ONSD and for the improvement of symptoms. Transtemporal window could not be obtained in six patients. At 12 h following VP shunt, bilateral median ONSD values reduced significantly from their pre-VP shunt values [right ONSD- 0.62 (0.59–0.64) to 0.53 (0.5–0.54) mm (p < 0.001); left ONSD- 0.62 (0.59–0.63) to 0.53 (0.5–0.54) mm (p < 0.001)]. Similarly, the median TVD at 12 h post-VP shunt reduced significantly from its pre-VP shunt measurements [0.97 (0.85–1.09) to 0.74 (0.7–0.84) cm]. PI MCA values reduced significantly, while Vm MCA values increased significantly from the pre-VP shunt values. ConclusionVP shunt reduced the ONSD, TVD, PI MCA and increased the Vm MCA after shunt surgery as early as 12hrs.

OBEZ HASTALARDA LAPAROSKOPİK CERRAHİLERDE FARKLI PEEP UYGULAMALARININ OPTİK SİNİR KILIF ÇAPINA ETKİSİNİN DEĞERLENDİRİLMESİ

OBJECTIVE: Positive end-expiratory pressure (PEEP) application, which is used to improve oxygenation by keeping the alveoli open, may cause an additional increase in intracranial pressure (ICP) during pneumoperitoneum in obese patients. In this study, the effect of different PEEP applications on the optic nerve sheath diameter (ONSD) in obese patients undergoing laparoscopic surgery was evaluated. MATERIAL AND METHODS: The study included 26 patients with a Body Mass Index (BMI) of ≥ 30 and the American Society of Anesthesiologists (ASA) I-II status undergoing laparoscopic surgery in the reverse Trendelenburg position. After anesthesia induction, the patients were randomly allocated to either the PEEP 5 group or the PEEP 8 group. The patients were compared with respect to age, gender, BMI, ASA status, operations performed, and the hemodynamic data and ONSD values recorded intraoperatively at regular intervals. RESULTS: 22 patients completed the study. Except for gender (p=0.020), there was no difference in demographic and hemodynamic data between the groups. No difference was observed between the groups in respect of ONSD measurements at all times. In the intra-group comparisons, there was no difference in the ONSD values within the PEEP 5 group, whereas in the PEEP 8 group, the measurements at 5 minutes (T2) and 30 minutes (T3) after pneumoperitoneum, and at the end of surgery (T4) were significantly higher than the basal measurements (T1) (p=0.010, p=0.003, p=0.012). CONCLUSIONS: Although PEEP 8 and PEEP 5 applications have similar effects to ICP increase, we thought that it would be safer to apply PEEP increments by measuring ONSD via ultrasonography.

Monitoring of optic sheath diameter during acute migraine attack: an objective criteria for the severity of disease.

The etiology of migraine can be complex and multifactorial but not clear, also, intracranial pressure has been already associated with migraine attacks. This study aimed to monitor intracranial pressure during migraine attack to understand the possible relations with disease and severity. A prospective randomized study was designed. Patients with a definitive diagnosis of migraine underwent ultrasonography for optic nerve sheath diameter (ONSD) measurement before treatment and were re-measured after the attack was resolved. The severity of the migraine was assessed with Headache Impact Test-6 (HIT-6) and Migraine Disability Assessment (MIDAS) questionnaire before the treatment and after the symptoms regressed. ONSD values and scores from the questionnaires were compared before and after the migraine attack. The study included 11 (52.4%) women and 10 (47.6%) men, and 42 eyes were evaluated. ONSD was detected as 4.23 ± 0.26 mm in the right eye and 4.10 ± 0.32 mm in the left eye during the migraine attack and decreased to 3.65 ± 0.41 mm in the right eye and 3.50 ± 0.33 mm in the left eye after the attack was treated (p < 0.001, both). A similar statistical improvement was found in HIT-6 and MIDAS scores with ONSD after treatment (p < 0.001). A significant positive correlation was found between the ONSD value in both eyes and HIT-6/MIDAS scores during the migraine attack, and also, after the migraine attack. A subjective increase of ONSD values during the migraine attack decreased after the disease resolved, also changes in ONSD values were significantly correlated with the severity of symptoms.

Transorbital sonography in idiopathic intracranial hypertension: Single-center study, systematic review and meta-analysis.

Transorbital sonography (TOS) provides a noninvasive tool to detect intracranial pressure by assessing optic nerve sheath diameter (ONSD) and optic disc elevation (ODE). The utility of TOS in the diagnosis of idiopathic intracranial hypertension (IIH) has been increasingly recognized. A single-center case-control study sought to compare TOS-acquired ONSD and ODE among IIH-cases versus patients with other neurological diseases (controls). Furthermore, a systematic review and meta-analysis was conducted to present pooled mean differences and diagnostic measures of ONSD and ODE between IIH-cases and controls. In the single-center study, consisting of 31 IIH-cases and 34 sex- and age-matched controls, ONSD values were higher among IIH-cases than controls (p<.001), while ODE was more prevalent in cases (65%vs. 15%; p<.001). The receiver-operating characteristic (ROC)-curve analysis revealed that the optimal cutoff value of ONSD for predicting IIH was 5.15mm, with an area under the curve (AUC) of 0.914 (95% confidence interval [CI]: 0.861-0.967) and sensitivity and specificity values of 85% and 90%, respectively. In a meta-analysis of 14 included studies with 415 IIH-cases, ONSD and ODE values were higher in IIH-cases than controls (mean difference in ONSD 1.20mm; 95% CI: 0.96-1.44mm and in ODE 0.3mm; 95% CI: 0.33-0.67mm). With regard to ONSD, pooled sensitivity, specificity, and diagnostic odds ratio were calculated at 85.5% (95% CI: 77.9-90.8%), 90.7% (95% CI: 84.6-94.5%), and 57.394 (95% CI: 24.597-133.924), respectively. The AUC in summary ROC-curve analysis was 0.878 (95% CI: 0.858-0.899) with an optimal cutoff point of 5.0mm. TOS has a high diagnostic utility for the noninvasive diagnosis of IIH and may deserve wider implementation in everyday clinical practice.

Bir Pilot Çalışma: Kritik Hasta Yönetimi İçin Ölçülen Sonografik Optik Sinir Kılıfı Kalınlığına COVID-19'un Etkisi

Objective: The aim of this study is to evaluate the effects of the Coronavirus disease 2019 on sonographic optic nerve sheath diameter measurement and thus avoid possible misleading results in clinical practice.&#x0D; Material and Method: Each volunteer was first evaluated using carotid system color Doppler ultrasonography. Patients with a history of PCR-confirmed Coronavirus disease 2019 infection were classified as group 1 and patients without a history of Coronavirus disease 2019 infection were classified as group 2, and sonographic optic nerve sheath diameter values of both groups were analyzed.&#x0D; Results: Of the 123 patients included in the study, 70 (56.9%) were female and 58 (43.1%) were male. 83 (67.5%) of the patients included in the study were in group 1 and 40 (32.5%) were in group 2. The mean sonographic optic nerve sheath diameter values for the groups were 3.53 mm and 3.46 mm, respectively. The sonographic optic nerve sheath diameter differences between the two eyes for the groups were determined to be 0.203±0.139 mm and 0.282±0.2 mm.&#x0D; Conclusion: Due to the variable effects of Severe Acute Respiratory Syndrome Coronavirus-2, the use of sonographic optic nerve sheath diameter measurement in current standards for critical patient management may lead to false-positive or false-negative results.

Automated pupillometry and optic nerve sheath diameter ultrasound to define tuberculous meningitis disease severity and prognosis

BackgroundTuberculous meningitis (TBM) causes high mortality and morbidity, in part due to raised intracranial pressure (ICP). Automated pupillometry (NPi) and optic nerve sheath diameter (ONSD) are both low-cost, easy-to-use and non-invasive techniques that correlate with ICP and neurological status. However, it is uncertain how to apply these techniques in the management of TBM. MethodsWe conducted a pilot study enrolling 20 adults with TBM in the Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. Our objective was to investigate the relationships between baseline and serial measurements of NPi and ONSD and disease severity and outcome. Serial NPi and ONSD were performed for 30 days, at discharge, and at 3-months, with measurements correlated with clinical progression and outcomes. ResultsONSD and NPi measurements had an inverse relationship. Higher ONSD and lower NPi values were associated with lower Glasgow coma score. Baseline NPi was a strong predictor 3-month outcome (median NPi 4.55, interquartile range 4.35–4.65 for good outcomes versus 2.60, IQR 0.65–3.95 for poor outcomes, p = 0.002). Pupil inequality (NPi ≥0.7) was also strongly associated with poor 3-month outcomes (p = 0.006). Individual participants' serial NPi and ONSD were variable during initial treatment and correlated with clinical condition and outcome. ConclusionPupillometry and ONSD may be used to predict clinical deterioration and outcome from TBM. Future, larger studies are need explore the optimal timing of measurements and to define how they might be used to optimise treatments and improve outcomes from TBM.

A Novel Method for Prediction of Raised Intracranial Pressure Through Automated ONSD and ETD Ratio Measurement From Ocular Ultrasound.

The paper presents a novel framework for the prediction of the raised Intracranial Pressure (ICP) from ocular ultrasound images of traumatic patients through automated measurement of Optic Nerve Sheath Diameter (ONSD) and Eyeball Transverse Diameter (ETD). The measurement of ONSD using an ocular ultrasound scan is non-invasive and correlates with the raised ICP. However, the existing studies suggested that the ONSD value alone is insufficient to indicate the ICP condition. Since the ONSD and ETD values may vary among patients belonging to different ethnicity/origins, there is a need for developing an independent global biomarker for predicting raised ICP condition. The proposed work develops an automated framework for the prediction of raised ICP by developing algorithms for the automated measurement of ONSD and ETD values. It is established that the ONSD and ETD ratio (OER) is a potential biomarker for ICP prediction independent of ethnicity and origin. The OER threshold value is determined by performing statistical analysis on the data of 57 trauma patients obtained from the AIIMS, New Delhi. The automated OER is computed and compared with the conventionally measured ICP by determining suitable correlation coefficients. It is found that there is a significant correlation of OER with ICP (r = .81, p ≤ .01), whereas the correlation of ONSD alone with ICP is relatively less (r = .69, p = .004). These correlation values indicate that OER is a better parameter for the prediction of ICP. Further, the threshold value of OER is found to be 0.21 for predicting raised ICP conditions in this study. Scatter plot and Heat map analysis of OER and corresponding ICP reveal that patients with OER ≥ 0.21, have ICP in the range of 17 to 35 mm Hg. In the data available for this research work, OER ranges from 0.17 to 0.35.

Shear wave elastography combined with two-dimensional ultrasonography for detecting optic nerve sheath: An effective tool for assessing preeclampsia.

This study aimed to investigate two-dimensional ultrasound and shear-wave elastography (SWE) in evaluating optic neuropathy in preeclampsia. Ninety-one singleton pregnant women (51 with preeclampsia [observation group]; 40 without complications [control group]) admitted between January 2022 and April 2022 participated in this study. Optic nerve sheath diameter (ONSD) and optic nerve stiffness measurement (ONSM) were measured using two-dimensional ultrasound and SWE, respectively, and compared between the two groups. Receiver operating characteristic curves were employed to evaluate the performance of ONSD, ONSM, and combination (ONSD + ONSM) for diagnosing preeclampsia. The observation (preeclampsia) group ONSD and ONSM were significantly higher than those in the control group (p < 0.05). Optimal diagnostic values for ONSD and ONSM were 4.10 mm and 11.20 kPa, respectively. Areas under the curve for diagnosing preeclampsia were 0.958 (95% confidence interval [CI], 0.926-0.990) for ONSD, 0.939 (95% CI, 0.894-0.985) for ONSM, and 0.982 (95% CI, 0.962-1.000) for ONSD + ONSM. There was no significant difference between ONSD and ONSM in diagnosing preeclampsia (p = 0.436). However, ONSD + ONSM was significantly advantageous over ONSD or ONSM alone in diagnosing preeclampsia (p = 0.033; p = 0.014). Ultrasonic evaluation of the optic nerve can quantitatively assess optic nerve changes in pregnant women with preeclampsia.

B-mode transorbital ultrasonography for the diagnosis of idiopathic intracranial hypertension: an updated systematic review and meta-analysis.

This systematic review and meta-analysis aimed to evaluate the role of B-mode transorbital ultrasonography (TOS) for the diagnosis of idiopathic intracranial hypertension (IIH) in adults. MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) (1966-May 2022) were searched to identify studies reporting ultrasonographic data about the optic nerve sheath diameter (ONSD) and optic disc elevation (ODE) in adults with IIH compared to subjects without IIH. The quality of the included studies was evaluated by the Newcastle-Ottawa Quality. Fifteen studies were included (total of 439 patients). The values of ODE ranged from 0.6 to 1.3mm in patients with IIH. The values of ONSD ranged from 4.7 to 6.8mm in IIH patients and from 3.9 to 5.7mm in controls. In IIH patients, the ONSD was significantly higher compared to controls (standardized mean difference: 2.5mm, 95% confidence interval (CI): 1.6-3.4mm). Nine studies provided data about the presence of papilledema and the pooled prevalence was 95% (95% CI, 92-97%). In adults, the thickness of ONSD and the entity of ODE were significantly associated with IIH. B-mode TOS enables to noninvasively detect increased ICP and should be performed, potentially routinely, in any patient with suspected IIH.

Optic nerve sheath diameter measurement for prediction of postdural puncture headache.

Intracranial hypotension due to cerebrospinal fluid leak is mainly the causal factor for the pathophysiology of postdural puncture headache (PDPH). In this study, we aimed to evaluate the effectiveness of optic nerve sheath diameter (ONSD) measurement in predicting the development of PDPH in patients undergoing spinal anesthesia. According to the American Society of Anesthesiology (ASA) physical classification I-III, 83 patients aged 18-65 years scheduled for spinal anesthesia for elective surgery were included in the study. Demographic data (age, ASA, sex, smoking, migraine, and PDPH history) and operative data were recorded. Preoperative ONSD measurements were taken in the right and left eye, axial, and sagittal planes. The mean of four measurements was recorded before and 24h after the spinal anesthesia. A total of 83 patients (59 males and 24 females) were included in the study. In our study, the rate of PDPH development was determined as 22.9% (n = 19). There was a statistically significant difference in the preoperative and postoperative ONSD values between patients with and without PDPH development (p = 0.046). In the receiver operating characteristic analysis, the area under the curve was 0.843, and the cutoff value was 0.4. The difference between the ONSD values measured before and after spinal anesthesia may be an important parameter for predicting the risk of PDPH development.

Is optic nerve sheath diameter a promising screening tool to predict neurological outcomes and the need for secondary decompressive craniectomy in moderate to severe head injury patients? A prospective monocentric observational pilot study.

Optic nerve sheath diameter (ONSD) has been shown to be a noninvasive and quick method to calculate intracranial pressure (ICP) and subsequent neurologic outcomes, although with variable cutoffs. ICP can be indirectly assessed by noninvasive methods such as transcranial Doppler, ONSD, tympanic membrane displacement, and fundoscopy. Knowledge regarding the diagnostic accuracy of ONSD for predicting unfavorable outcomes within 72 hours (h) of moderate and severe head injury is limited. The objective of this study was to measure ONSD measurements at 24-h intervals in moderate to severe head injury patients and to find its association with clinical outcomes in the target population. This prospective observational study was done on moderate to severe head injury patients. ONSD was measured twice at 24-h intervals over 48 h. The clinical outcome was divided into the favorable group (patients who were in conservative treatment with a stable Glasgow Coma Scale [GCS] score and discharged following treatment) and the unfavorable group (patients who had a drop in GCS motor score of one or more, or expired or underwent surgical intervention) within 72 h following traumatic brain injury. The Kruskal-Wallis test, Mann- Whitney test, and receiver operating characteristic curves were used to establish the association between ONSD and clinical outcomes. ONSD values measured at 24-h intervals >6.1 mm (P < 0.0146) and 6.2 mm (P < 0.0001) were found to be predictors of unfavorable outcomes (expired or underwent surgery), and hence the need for a secondary decompressive craniectomy (DC). ONSD is an efficient screening tool to assess neurological outcomes in severe head injury patients. It can reliably predict the need for secondary DC at an earlier stage before secondary brain damage ensues in these patients.

Comparison of extraperitoneal and intraperitoneal laparoscopic procedures for intracranial pressure increase: a prospective clinical study.

According to the literature, higher levels of both intracranial pressure (ICP) and intraabdominal pressure (IAP) are related in a way that suggests a causal relationship. An increase in ICP can cause major neurological problems both during and after laparoscopic surgery. In this study, we aimed to examine the increase in ICP between totally extraperitoneal (TEP) inguinal hernia repair and laparoscopic cholecystectomy. We investigated 52 individuals who underwent laparoscopic surgery for the treatment of inguinal hernia (n = 26) or had a laparoscopic cholecystectomy (n = 26). The optic nerve sheath diameter (ONSD) was assessed before the procedure (T0), 10 minutes after carbon dioxide insufflation (T1), and immediately before extubation (T2). There were significant differences in the ONSD values between the two groups as a function of time (p = 0.001). In terms of ONSD, the laparoscopic cholecystectomy value (LV) group showed a greater shift from T0 to T1 and T2 than the inguinal hernia value (HV) group. At T1, the ONSD values of both groups were considerably higher than those of T0 and T2. The impact of the extraperitoneal and transperitoneal laparoscopic methods on ICP was investigated. The ONSD value reached its maximum at T1 in both groups. At all measurement periods, the ONSD values of the LV group were noticeably higher than those of the HV group. The diagnostic accuracy of ONSD ultrasonography is an important approach for determining the ICP level. During the decision-making process of TEP inguinal hernia repair, this study can guide medical professionals in the evaluation of elevated ICP.