Optic Nerve Sheath Diameter Research Articles

Relevance of optic nerve B-mode sonography in multiple sclerosis diagnosis and follow-up

Abstract Background Among young people, multiple sclerosis (MS) accounts for the majority of non-traumatic neurological impairments. Almost all MS patients develop optic neuritis as the illness progresses. In MS, the optic nerve (ON) is vulnerable to demyelinating injury and is considered “eloquent” in comparison with the brain. Thus, it serves as a clinical model for MS. Since the eye is a suitable target for ultrasonography due to its high-water content, non-invasive trans-orbital sonography (TOS) can determine the optic nerve sheath diameter (ONSD). This research aimed to determine the effectiveness of ON ultrasonography as a simple, low-cost method for diagnosing and following up MS patients, facilitating their treatment plan. It correlates the findings of ONSD using TOS and visual-evoked potential (VEP), the number of magnetic resonance imaging (MRI) black holes, and other clinically significant parameters in 30 relapsing–remitting MS (RRMS) patients versus 30 controls. Results We examined a total of 120 eyes. The ONSD values at 3 mm, 5 mm, and myelination index were significantly lower in the patients (4.7 ± 0.3, 5.5 ± 0.3, and 0.86 ± 0.03, respectively) versus the controls (5.6 ± 0.3, 6.2 ± 0.4, and 0.90 ± 0.03, respectively) (p < 0.001 in each). The mean P 100 latency was significantly delayed in the patients (125.5 ± 6.1 ms) than the controls (100.2 ± 3.3 ms), (p < 0.001). The mean VEP amplitude was significantly lower in the patients (4.9 ± 0.7 μV) than the controls (6.8 ± 0.8 μV) (p < 0.001). There was a highly significant positive correlation between the ONSD and P 100 amplitude, and highly significant negative correlations between the ONSD and disease duration, number of optic neuritis attacks, EDSS, MRI black holes number, and P 100 latency. Conclusions Trans-orbital sonography is a practical and easily accessible approach for assessing ON atrophy in MS. It can measure axonal loss and brain atrophy indirectly and is a reliable paraclinical diagnostic tool, suggesting that ONSD could be a biomarker of disease activity.

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

Intracranial hypertension (IH) is associated with an unfavorable outcome in traumatic brain injury (TBI), and management strategies guided by intracranial pressure monitoring improve prognosis. Owing to the limitations of using invasive devices, measurement of optic nerve sheath diameter (ONSD) by ultrasonography is an alternative noninvasive method. However, its accuracy has not been validated in patients with TBI, so we aim to determine the diagnostic accuracy of measuring ONSD by ultrasonography in patients with TBI to estimate IH, compared with invasive monitoring. Systematic review of electronic databases and manual literature review from inception to June 2023. The analysis included diagnostic accuracy studies of ultrasonographic measurement of ONSD compared with invasive monitoring published in any language and with patients of any age. A qualitative synthesis was performed describing the clinical and methodological characteristics, strengths, limitations, and quality of evidence. In addition, a bivariate random effects model meta-analysis and a hierarchical summary receiver operating characteristics model were performed for the pediatric and adult population separately. Five hundred and forty eight patients of 688 in 16 eligible studies were adults and 120 were children. Pooled sensitivity and specificity of ONSD measurement by ultrasonography were 84% (95% CI, 76%-89%) and 83% (95% CI, 73%-90%), respectively. During the sensitivity analysis, these parameters exhibited consistent values. Pooled area under the curve was 0.91 for adults and 0.76 for children. Optimal threshold for estimating IH was 5.76 mm for adults and 5.78 mm for children. Measurement of ONSD by ultrasonography is a reliable, low-cost, and safe alternative for the estimation of IH with TBI in adults. More robust studies are needed to overcome the high risk of bias and heterogeneity for this analysis.

The effectiveness of optic nerve sheath diameter in predicting large vessel occlusion in ischemic stroke patients

Aim: This study assessed the effectiveness of ultrasonography-measured optic nerve sheath diameter (ONSD) in predicting large vessel occlusion (LVO) in ischemic stroke patients.Materials and methods: This single-center, prospective observational study involved patients presenting to the emergency department within 24 hours of symptom onset with moderate to severe stroke, and healthy volunteers.Results: The study included 133 ischemic stroke patients and 63 healthy volunteers. The patient group had significantly higher right [5.8 (0.9)] and left [5.9 (0.8)] ONSD values compared to controls (right [5.7 (0.6)], left [5.7 (0.8)], p<0.001 for both). LVO was present in 58.6% (n = 78) of patients. Median right ONSD was 6.1 mm (0.8) in LVO patients vs. 5.7 mm (0.65) in non-LVO patients (p=0.002). Median left ONSD was 5.9 mm (0.9) in LVO patients vs. 5.7 mm (0.7) in non-LVO patients (p=0.002). A right ONSD ≥6 mm had 51.28% sensitivity and 78.18% specificity for LVO. A left ONSD ≥5.5 mm had 83.33% sensitivity and 40% specificity for LVO.Conclusion: Elevated ONSD values measured by ultrasonography can effectively indicate LVO in stroke patients.

The association of early passive mobilization with intracranial pressure in the adult intensive care unit: A prospective, cohort study.

Early mobilization are key components of the ABCDEF Care Bundle and critical treatments to reduce acquired muscle weakness, delirium and prolonged intensive care unit (ICU) stay. This study aimed to determine whether routine early mobilization related to intracranial pressure in intensive care patients on mechanical ventilation, using optic nerve sheath diameter measurement (ONSD). This study was planned as a prospective, cohort study in the third-step adult ICU of a faculty hospital. The study included only patients who were intubated and followed up on a mechanical ventilator and were clinically stable. Passive range of motion (PROM) exercises were performed daily by the physiotherapists as part of routine care from the day of hospitalization. ONSD was assessed before, during and 10 min after PROM exercises. The study included 20 eligible patients out of the 142 who were evaluated upon admission to the ICU. The median age of the patients was 65 years, and nine (45%) of them were female. The analyses showed that there was no statistically significant change in ONSD during and at the end of the PROM (ONSD right eye p:.621, Partial η2: 0.025, ONSD left eye p:.935, Partial η2: 0.004). Similarly, there was no statistically significant change in haemodynamic parameters in during and at the end of the PROM (Heart beat p:.849, Partial η2: 0.009, Systolic Pressure p:.435, Partial η2: 0.043, Diastolic Pressure p:.128, Partial η2:0.103, Saturation p:.103, Partial η2: 0.113 and Respiratory rate p:.071, Partial η2:0.130). This study suggests that daily extremity physiotherapy exercises can be safely applied without causing increased intracranial pressure or haemodynamic instability in intensive care patients followed up on mechanical ventilation, including patients with vasopressor therapy. Early mobilization, including PROM, is considered safe in terms of intracranial pressure for intubated patients in the ICU.

Potential of observing the diameter of the optic nerve sheath using computed tomography in diagnosing high intracranial pressure in patients with spontaneous CSF rhinorrhea.

Spontaneous cerebrospinal fluid rhinorrhea (sCSFR) is often accompanied by an increase in intracranial pressure (ICP). The widening of optic nerve sheath diameter (ONSD) is an indicator of increased ICP. Using CT to measure ONSD is a simple and noninvasive auxiliary method for determining high ICP in sCSFR patients.

Evaluation of the Normal Measurements of Orbital Structures in Healthy Adult Individuals by Using a Magnetic Resonance Imaging Method

Background: This study aims to determine the normal values of orbital structures according to sex in healthy adults. Methods: Diameters of extraocular muscles, the width of the optic nerve sheath diameter, the length of the inter-zygomatic line, ocular bulb length, and globe position were measured in the T1-weighed MR (magnetic resonance) images in 204 orbits of 102 individuals. Results: The mean values of the diameters of the extraocular muscles in males and females were as follows: medial rectus, 3.96 ± 0.52 and 3.58 ± 0.53 mm; lateral rectus, 3.47 ± 0.61 and 3.15 ± 0.48 mm; inferior rectus, 4.47 ± 0.53 and 4.07 ± 0.48 mm; superior rectus, 4.44 ± 0.64 and 4.01 ± 0.56 mm; and superior oblique, 3.68 ± 0.49 and 3.45 ± 0.44 mm. The length of the interzygomatic line in males and females were 102.68 ± 3.89 and 96.95 ± 3.4 mm, the ocular bulb length was 23.33 ± 1.32 and 22.83 ± 1.1 mm, the globe position was 7.66 ± 1.33 and 7.3 ± 1.39 mm, and the width of the optic nerve sheath diameter was 4.65 ± 0.62 and 4.28 ± 0.51 mm, respectively. All measurements were significantly greater for males than for females (p < 0.05). Conclusions: We believe that a practical and quantitative method will be provided by this study for the diagnosis and determination of the normative values of orbital structures.

Prediction of poor prognosis using the peak systolic velocity and early diastolic velocity of the central retinal artery in patients with post‐cardiac arrest syndrome

AbstractIntroductionMonitoring intracranial pressure (ICP) in patients with post‐cardiac arrest syndrome (PCAS) is crucial for effective management and prognosis assessment. However, continuous ICP monitoring is rarely practiced. Increased ICP is often associated with the impairment of brain autoregulation. This study investigated whether central retinal artery (CRA) flow velocity, autoregulation status according to mean arterial pressure (MAP), and the optic nerve sheath diameter (ONSD)/eyeball transverse diameter (ETD) ratio could predict poor prognosis related to increased ICP in PCAS patients.MethodsIn this multicenter prospective observational study, transocular ultrasonography of the optic nerve sheath was performed on 38 PCAS patients treated with targeted temperature management from December 2021 to November 2022. CRA peak systolic velocity (PSV), early diastolic velocity (eDV), MAP, CRA‐PSV changes following MAP changes (autoregulation), and ONSD/ETD ratio were measured repeatedly from days 0 to 4 post‐admission.ResultsUnivariable analysis indicated that CRA‐PSV, nonpositive or flat CRA‐eDV, and disrupted autoregulation correlated with a poor prognosis (Cerebral Performance Category 4 or 5). In multivariable analysis, nonpositive CRA‐eDV or disrupted autoregulation was the most significant predictor of poor prognosis (odds ratio, 40.576; p = 0.002), with an area under the curve of 0.774. The ONSD/ETD ratio did not show a significant correlation.ConclusionsNonpositive CRA‐eDV, CRA‐PSV and disrupted autoregulation can predict poor prognosis in PCAS patients. Transocular Doppler ultrasonography of the CRA and autoregulation assessment may aid in ICP monitoring and management in PCAS patients.

Sinus vein thrombosis conundrum: Persistent empty sella vs. flexible optic nerve sheath

IntroductionOur objective was to investigate the potential effect of thrombotic burden on pituitary gland height, bony sella and optic sheath width, taking into consideration the various venous sites and dominant drainage pattern. Patients and MethodsThis retrospective cohort study followed patients diagnosed with cerebral sinus vein thrombosis in a single primary healthcare center between the years 2000 and 2022. Data was collected from both CT/V and MR/V scans available on the local PACS system. Dural sinuses were divided into main anatomical sites and scored for patent, partially or totally blocked lumen. Dominant drainage flow was noted for each patient. For most scans, pituitary mid height, maximal depth and AP width of the bony sella and dorsum sella to tuberculum sella distance were assessed. Optic sheath width was measured for both sides at the maximal retrobulbar diameter. Regression methods, including linear mixed models, and non-parametric tests were used to analyze the data. Results90 patients (mean age, 44 years ±16.8, 54 women) were evaluated. Overall thrombus burden did not correlate with pituitary mid-height, however a relationship was observed between the change (from presentation) in the superficial thrombus score and the average width of the optic nerve sheath; the width of the optic sheath tended to decrease as thrombus burden improved and vice versa (p = 0.010). ConclusionsThrombus recanalization had a favorable effect on the optic nerve sheath diameter but did not appear to reverse the flattening of the pituitary gland, regardless of temporal improvement.

Effect of needle types and diameters using in spinal anesthesia on optic nerve sheath diameter: Prospective randomized study.

This prospective randomized study aimed to investigate the impact of needle types and diameters used in spinal anesthesia (SA) on optic nerve sheath diameter (ONSD) in patients undergoing lower extremity orthopedic surgery. Patients were randomly assigned to 3 groups based on the needle type and size used for SA: Group 25w (25 gauge Whitacre needle), Group 27q (27 gauge Quincke needle), and Group 25q (25 gauge Quincke needle). Initially, 165 patients (55 in each group) were enrolled, with 146 patients ultimately included in the analysis (Group 25w, n = 49; Group 27q, n = 48; Group 25q, n = 49). ONSD measurements were conducted using ultrasound guidance at 5 time points: T0 (pre-SA), T1 (5 minutes post-SA), T2 (5 minutes post-tourniquet inflation), T3 (5 minutes post-tourniquet deflation), and T4 (24 hours post-operation). Additionally, oxygen saturation, systolic arterial pressure, mean arterial pressure, diastolic arterial pressure, and heart rate were recorded at these time points. Analysis of ONSD measurements revealed no significant differences among the groups at time points T0,T1,T2, and T4 (P = .7293, P = .4428, P = .3676, and P = .3667, respectively). However, at T3, ONSD values were significantly higher in Group 27q compared to Group 25q (P = .0325). Across all groups, the mean ONSD values measured post-tourniquet release (T3) were higher than those at T0,T2, and T4 (P < .001 for all). The incidence of nausea was similar among the groups, and no cases of headache or visual impairment were reported within the initial 24 hours post-surgery. In conclusion, our study suggests that while subarachnoid injection and tourniquet inflation do not impact intracranial pressure (ICP), tourniquet deflation leads to an increase in ICP during lower limb surgery under SA. Therefore, caution should be exercised when using a tourniquet in patients at risk of elevated ICP.

The optic nerve sheath in hypertensive disorders of pregnancy and perinatal outcomes: a cohort study

BackgroundPreeclampsia is implicated in 14% of maternal deaths worldwide, mostly due to complications such as intracranial hemorrhage and cerebral edema. Cerebral edema increases intracranial pressure, which can be predicted by ultrasonographic measurement of the optic nerve sheath diameter (ONSD). Greater diameters have been reported in women with preeclampsia and eclampsia; however, data are lacking on the possible association with maternal and neonatal adverse outcomes. This study aimed to determine whether there is an association between hypertensive disorders of pregnancy and the ONSD, and between this measurement and maternal and neonatal adverse outcomes.MethodsThis was a cohort study involving 183 women in the third trimester of pregnancy or within 24 h following childbirth, distributed as follows: control group (n = 30), gestational hypertension (n = 14), chronic hypertension (n = 12), preeclampsia without severe features (n = 12), preeclampsia with severe features (n = 62), superimposed preeclampsia (n = 23) and eclampsia (n = 30). The participants underwent ocular ultrasonography, and data on maternal and neonatal outcomes were collected from the medical records. To compare the groups, analysis of variance was used for the normally distributed numerical variables and the Kruskal–Wallis test was used for variables with non-normal distribution. Two-tailed p-values ≤ 0.05 were considered statistically significant.ResultsOverall comparison between the seven groups showed no statistically significant difference in the mean ONSD (p = 0.056). Nevertheless, diameters were significantly greater in the eclampsia group compared to the control group (p = 0.003). Greater diameters were associated with maternal admission to the intensive care unit (ICU) (p < 0.01) and maternal near miss (p = 0.01). There was no association between ONSD and admission to the neonatal ICU (p = 0.1), neonatal near miss (p = 0.34) or neonatal death (p = 0.26).ConclusionsNo association was found between ONSD and the hypertensive disorders of pregnancy in the overall analysis; however, ONSD was greater in women with eclampsia compared to controls. Greater diameters were associated with maternal admission to the ICU and maternal near miss. These findings suggest a potential use for bedside ultrasound as an additional tool for stratifying risk in patients with hypertensive disorders of pregnancy.

Pcv-aCO2/Ca-cvO2 Combined with Optic Nerve Sheath Diameter in Predicting Elevated Intracranial Pressure of Patients with Traumatic Brain Injury in Prehospital Setting.

To investigate a correlation between the central venous minus arterial CO2 pressure to arterial minus central venous O2 content ratio (Pcv-aCO2/Ca-cvO2) combined with optic nerve sheath diameter (ONSD) in predicting prehospital elevated intracranial pressure (ICP) in traumatic brain injury (TBI) patients. This was a prospective observational study of all adult TBI patients from the surgical intensive care unit who underwent invasive ICP monitoring between January 2023 and December 2023. Using a Delica MVU-6300 machine with 14-5 MHz linear probe to measure ONSD. We drew blood samples for arterial and central venous blood gases to measure and calculate the following indicators such as Pcv-aCO2, Ca-cvO2, and Pcv-aCO2/Ca-cvO2 ratio. ONSD and Pcv-aCO2/Ca-cvO2 were recorded during the first 3 days after admission. Simultaneous ICP values were gained from the invasive monitoring. Associations between ONSD, Pcv-aCO2/Ca-cvO2 and simultaneous ICP were explored by Spearman correlation analysis. We constructed an ROC curve to identify the ONSD and Pcv-aCO2/Ca-cvO2 cutoff for the evaluation of elevated ICP. We included 54 patients aged mean 57.13 (standard deviation 4.02) years and 24 (44%) were male. A significant correlation was observed between ONSD and ICP (r = 0.74, P < 0.01). The AUC was 0.861 (95% CI: 0.727-0.951), with a best cutoff value of 5.62 mm. Using a cutoff of 5.62mm, ONSD had a sensitivity of 92.8%, specificity of 80.4%. The Pcv-aCO2/Ca-cvO2 ratio also significantly correlated with ICP (r = 0.70, P < 0.01). The AUC was 0.791 (95% CI: 0.673-0.889). The optimal Pcv-aCO2/Ca-cvO2 value for predicting elevated ICP was 1.98mmHg/mL. Using a cutoff of 1.98mmHg/mL, Pcv-aCO2/Ca-cvO2 had a sensitivity of 87.3%, specificity of 77.2%. The AUC for ONSD combined with Pcv-aCO2/Ca-cvO2 was 0.952 (95% CI: 0.869-0.971), which had a sensitivity of 95.1%, specificity of 93.9%. Pcv-aCO2/Ca-cvO2 combined with ONSD performed best in predicting elevated intracranial pressure of patients with TBI in a prehospital setting. Our findings provide a crucial tool to improve earlier management of these patients in prehospital care, where the availability and utilization of invasive monitoring is limited. It could lead to significant changes in how TBI patients are monitored and treated before reaching a hospital.

Optic nerve sheath diameters predict mortality and severity in hepatic encephalopathy.

The aim of this study was to compare the predictive power of optic nerve sheath diameter (ONSD) measured by brain computed tomography (CT) in patients diagnosed with hepatic encephalopathy (HE) in the emergency department, with other factors for mortality and disease severity. A total of 217 patients aged 18 years and older with acute decompensation of cirrhosis diagnosed with HE in the emergency department were included in the study. To compare with patients diagnosed with HE, a total of 217 individuals were included in the study as the healthy control group. ONSD measurements were performed on both the HE patients and the healthy control group in the brain CT. The mortality rate of HE patients was 32.7%. Regarding the severity of the disease, 53% of the patients had late-stage HE. The presence of acute-on-chronic liver failure was detected in 51.4% of patients. The mortality rate among acute-on-chronic liver failure patients was 56.6%. According to the study data, ONSD, creatinine, lactate, and procalcitonin were independent predictors of mortality. Meanwhile, Child-Pugh score, direct bilirubin, ONSD, ammonia, and total bilirubin were independent predictors of disease severity. In the receiver operating characteristic curve analysis, the ONSD had the highest predictive power for mortality and disease severity among the determined predictive values. The data from the study suggests that assessing the ONSD through brain CT scans in individuals diagnosed with HE in the emergency department may provide valuable insights for clinicians, aiding in the prediction of both mortality rates and the severity of the disease.

Perioperative and postoperative effects of hydrostatic pressure applied to the dura mater on central nervous system in unilateral biportal endoscopic spine surgery.

To evaluate the changes in optic nerve sheath diameter (ONSD) caused by this pressure applied to the dura mater and postoperative complications. The study was conducted between 01.01.2022 and 01.06.2022 at Private Medicabil Hospital. The ONSD was measured 3mm behind the eyeball using US at 5 time points: T1 (in the supine position after anesthesia induction), T2 (after conversion to the prone position), T3 (in the prone position after applying pressure to the dura mater), T4 (in the prone position after the discontinuation of applying pressure to the dura mater), T5 (after conversion to the supine position). Postoperative complications were recorded. The ONSD at T3 was higher than those at all time points. For an ONSD value >5.3mm, the sensitivity, specificity, positive predictive, and negative predictive values were 87.5%, 71.9%, 50.9%, and 94.5%, respectively (Area under the curve 0.830, 95% Confidence Interval: 0.761-0.899, p<0.001) CONCLUSION: We think that the hydrostatic pressure applied to the dura mater in unilateral biportal endoscopic (UBE) surgeries causes changes in the ONSD sheath diameter and that monitoring ONSD with peroperative USG can reduce the possible complications in order to reduce the effects of this pressure on the central nervous system.

264 Changes in Optic Nerve Sheath Diameter Following Rigid Cervical Collar Application in Patients With Traumatic Brain Injury: A Prospective Observational Study in a Tertiary Care Teaching Hospital

264 Changes in Optic Nerve Sheath Diameter Following Rigid Cervical Collar Application in Patients With Traumatic Brain Injury: A Prospective Observational Study in a Tertiary Care Teaching Hospital

The relationship between optic nerve sheath diameter and demographic and clinical findings in patients diagnosed with clinically isolated syndrome

Aim: This study aimed to assess optic nerve sheath diameter (ONSD) levels in patients diagnosed with clinically isolated syndrome (CIS) who were being followed in the demyelinating diseases clinic, as well as to examine their relationship with demographic characteristics and clinical findings. Material and Methods: In this cross-sectional prospective study, 14 patients diagnosed with CIS who underwent lumbar puncture for specific cerebrospinal fluid (CSF) analysis were included between January 2024 and August 2024. The ONSD were measured by transorbital sonography. All patients' demographic characteristics, clinical parameters (CSF protein, CSF albumin, serum albumin, immunoglobulin G index, and vitamin D) were recorded. Results: The patients had a mean age of 39.4 ± 12.8 years, and the majority were women. Oligoclonal bands were positive in all patients. The mean disease duration was 23.5 ± 7.6 days. The ONSD measurements for all patients ranged between 3.1 and 5.9 mm in the sagittal and axial planes of both eyes. There was a strong negative correlation between ONSD levels and age, diseases duration, CSF protein, CSF albumin, serum albumin, and immunoglobulin G index. Conclusion: This study demonstrated a significant relationship between ONSD and various clinical and laboratory parameters in patients diagnosed with CIS. These findings suggest that ONSD may serve as a valuable, non-invasive marker in assessing disease severity and progression in CIS patients.

Suspected intracranial hypertension in COVID-19 patients with severe respiratory failure.

COVID-19 patients may exhibit neurological symptoms due to direct viral damage, systemic inflammatory syndrome, or treatment side effects. Mechanical ventilation in patients with severe respiratory failure often requires sedation and neuromuscular blockade, hindering thorough clinical examinations. This study aimed to investigate neurological involvement through clinical and noninvasive techniques and to detect signs of intracranial hypertension in these patients. We conducted a prospective observational study on mechanically ventilated COVID-19 adult patients admitted to our ICU, following standard of care protocols for ventilation and permissive hypercapnia. Data were collected at three time points: admission day (T1), day seven (T7), and day fourteen (T14). At each time point, patients underwent multimodal noninvasive neurological monitoring, including clinical examination, pupillary reactivity, transcranial color doppler of the middle cerebral artery (MCA), and optic nerve sheath diameter (ONSD) assessed via ultrasound (US). Head computer tomography (CT) was performed at T1 and T14. A limited subset of patients had a follow-up examination six months after ICU discharge. Seventy-nine patients were recruited; most were under deep sedation and neuromuscular blockade at T1. Pupillary size, symmetry, and reactivity were normal, as was the MCA mean velocity. However, ONSD, assessed by both US and CT, appeared enlarged, suggesting raised intracranial pressure (ICP). In a subgroup of 12 patients, increased minute ventilation was associated with a significant decrease in US-ONSD, corresponding to a drop in paCO2. At follow-up, twelve patients showed no long-term neurological sequelae, and US-ONSD was decreased in all of them. In this cohort, enlarged ONSD was detected during non-invasive neurological monitoring, suggesting a raised ICP, with hypercapnia playing a prominent role. Further studies are needed to explore ONSD behavior in other samples of mechanically ventilated, hypercapnic patients.

Ultrasonographic Measurement of Optic Nerve Sheath Diameter in Patients with Traumatic Head Injury: A Prospective Observational Study

Introduction: The early detection of elevated intracranial pressure is crucial for guiding interventions and improving patient outcomes in head injury patients. The intracranial pressure assessment with invasive intracranial devices is the gold standard. These devices however has a risk of infection, bleeding and dislodgement. Optic nerve sheath diameter measurement using ultrasonography has emerged as a promising method for indirect intracranial pressure estimation. Aims: To observe the changes in optic nerve sheath diameter over period of time, and to correlate the optic nerve sheath diameter with computed tomography findings of raised intracranial pressure in traumatic head injury. Methods: A prospective cross-sectional time series study was conducted at Nepalgunj Medical College to assess the utility of ultrasonography measurement of optic nerve sheath diameter in patients with head injuries from August 2023 to January 2024. Forty-nine patients with head injuries were included in the study. The ultrasonographic optic nerve sheath diameter measurements were obtained at admission, 48 hours post-admission, and 1 month post-head injury. The clinical parameters including Glasgow Coma Scale and radiological findings from Computed Tomography head were recorded. Results: Forty nine patients were enrolled in the study. Among them, 44.90% (27) were male and 55.10% (22) were female. Age ranged from 5 to 66 years, with a mean of 33.94 ± 15.27 years. The mean optic nerve sheath diameter was 5.24±0.86 mm at admission which decreased to 4.31±0.62 mm at 48 hours and 4.02±0.47 mm at 1 month. Our study showed significant reduction in optic nerve sheath diameter after conservative or surgical treatment in patients with head injury (F = 27.017; P =0.002) Conclusion: The ultrasonographic measurement of optic nerve sheath diameter proved to be a valuable tool in monitoring intracranial pressure in patients with head injuries.

Investigating Optic Nerve Sheath Diameter in Prone Position Spinal Surgery Patients: A Pilot Study.

This study aimed to evaluate the effect of intraoperative positioning and ocular immobility on the amount of cerebrospinal fluid around the optic nerve in patients undergoing prone spinal surgery by measuring the optic nerve sheath diameter (ONSD) using ultrasound. Consecutive participants (n = 15 patients, 30 eyes) were scanned preoperatively, intraoperatively approximately 20 minutes before the end of the surgery, and postoperatively in the post-anesthesia care unit at least 10 min after the completion of the surgery at one academic hospital. On average, patients who underwent prone spinal surgery had a 21% increase in ONSD intraoperatively, with a positive time-dependent relationship with the overall length of surgery (P 0.001). ONSDs postoperatively returned to baseline and were not significantly different from preoperative measurements. Our findings suggest pooling and inadequate clearance of perioptic cerebrospinal fluid during prone spinal surgery that improves following termination of the procedure and return of the patient to an upright position.

Optic Nerve Sheath Ultrasound Image Segmentation Based on CBC-YOLOv5s

The diameter of the optic nerve sheath is an important indicator for assessing the intracranial pressure in critically ill patients. The methods for measuring the optic nerve sheath diameter are generally divided into invasive and non-invasive methods. Compared to the invasive methods, the non-invasive methods are safer and have thus gained popularity. Among the non-invasive methods, using deep learning to process the ultrasound images of the eyes of critically ill patients and promptly output the diameter of the optic nerve sheath offers significant advantages. This paper proposes a CBC-YOLOv5s optic nerve sheath ultrasound image segmentation method that integrates both local and global features. First, it introduces the CBC-Backbone feature extraction network, which consists of dual-layer C3 Swin-Transformer (C3STR) and dual-layer Bottleneck Transformer (BoT3) modules. The C3STR backbone’s multi-layer convolution and residual connections focus on the local features of the optic nerve sheath, while the Window Transformer Attention (WTA) mechanism in the C3STR module and the Multi-Head Self-Attention (MHSA) in the BoT3 module enhance the model’s understanding of the global features of the optic nerve sheath. The extracted local and global features are fully integrated in the Spatial Pyramid Pooling Fusion (SPPF) module. Additionally, the CBC-Neck feature pyramid is proposed, which includes a single-layer C3STR module and three-layer CReToNeXt (CRTN) module. During upsampling feature fusion, the C3STR module is used to enhance the local and global awareness of the fused features. During downsampling feature fusion, the CRTN module’s multi-level residual design helps the network to better capture the global features of the optic nerve sheath within the fused features. The introduction of these modules achieves the thorough integration of the local and global features, enabling the model to efficiently and accurately identify the optic nerve sheath boundaries, even when the ocular ultrasound images are blurry or the boundaries are unclear. The Z2HOSPITAL-5000 dataset collected from Zhejiang University Second Hospital was used for the experiments. Compared to the widely used YOLOv5s and U-Net algorithms, the proposed method shows improved performance on the blurry test set. Specifically, the proposed method achieves precision, recall, and Intersection over Union (IoU) values that are 4.1%, 2.1%, and 4.5% higher than those of YOLOv5s. When compared to U-Net, the precision, recall, and IoU are improved by 9.2%, 21%, and 19.7%, respectively.

Optic nerve sheath diameters in nontraumatic brain injury: A scoping review and role in the intensive care unit.

Neuromonitoring in medical intensive care units is challenging as most patients are unfit for invasive intracranial pressure (ICP) modalities or unstable to transport for imaging. Ultrasonography-based optic nerve sheath diameter (ONSD) is an attractive option as it is reliable, repeatable and easily performed at the bedside. It has been sufficiently validated in traumatic brain injury (TBI) to be incorporated into the guidelines. However, currently the data for non-TBI patients is inconsistent for a scientific recommendation to be made. To compile the existing evidence for understanding the scope of ONSD in measuring ICP in adult non-traumatic neuro-critical patients. PubMed, Google Scholar and research citation analysis databases were searched for studies in adult patients with non-traumatic causes of raised ICP. Studies from 2010 to 2024 in English languages were included. We found 37 articles relevant to our search. The cutoff for ONSD in predicting ICP varied from 4.1 to 6.3 mm. Most of the articles used cerebrospinal fluid opening pressure followed by raised ICP on computed tomography/magnetic resonance imaging as the comparator parameter. ONSD was also found to be a reliable outcome measure in cases of acute ischaemic stroke, intracerebral bleeding and intracranial infection. However, ONSD is of doubtful utility in septic metabolic encephalopathy, dysnatremias and aneurysmal subarachnoid haemorrhage. ONSD is a useful tool for the diagnosis of raised ICP in non-traumatic neuro-critically ill patients and may also have a role in the prognostication of a subset of patients.