Optic Nerve Sheath Diameter In Patients Research Articles

Optic Nerve Sheath Diameter on Brain Magnetic Resonance Imaging: A Single Center Study

Background: Optic nerve sheath diameter (ONSD) on ultrasonography is regarded as an indirect and non-invasive marker to estimate intracranial pressure (ICP). Despite its popularity in clinical use, no data exist on Korean patients without ICP crisis. The main purpose of this study was to measure ONSD in patients with apparently normal ICP using magnetic resonance imaging (MRI). Methods: A consecutive 301 patients admitted to our institute who underwent MRI and/or magnetic resonance angiography (MRA) were included in this study. Source imaging with thin section slice was collected. ONSD was measured bilaterally using MIPAV software. Mean value was compared in terms of age, sex, and neurologic diagnosis. Results: The mean age of the 301 patients was 59.7±17.8 years. There were 171 (56.8%) males. Indication of brain imaging was stroke (n=136, 45.5%), epilepsy (n=45, 15.0%), neuromuscular disorder (n=29, 9.6%), movement disorder (n=28, 9.3%), and others (n=62, 20.6%). No patient had suspicion of ICP increase due to mass effect. Mean ONSD on MRA was 4.37±0.52 mm (male: 4.42±0.49 mm; female: 4.32±0.54 mm) (P=0.09). ONSD was not significantly different according to age group or underlying disease. Conclusion: The mean ONSD on MRI was 4.37 mm in patients with apparently normal ICP. ONSD was not significantly different in patients with different sex, age, or underlying disease. J Neurocrit Care 2015;8(1):16-24

Detection of elevated intracranial pressure in robot-assisted laparoscopic radical prostatectomy using ultrasonography of optic nerve sheath diameter.

Robot-assisted laparoscopic radical prostatectomy (RALRP) is becoming an increasingly frequent procedure. Pneumoperitoneum and steep trendelenburg positioning associated with this surgery may increase patient's risk for elevated intracranial pressure (ICP). We conducted a prospective observational trial using ultrasonographic analysis of optic nerve sheath diameter (ONSD) to determine if ICP increased to levels >20 mm Hg during RALRP surgery. The study includes 25 patients, without any history of increased ICP, undergoing RALRP. Ultrasonographic analysis of ONSD was performed immediately after induction of general anesthesia and again at the end of the procedure. A threshold value of ≥5.2 mm for ONSD was used for determination of raised ICP (>20 mm Hg). Age, race, body mass index, American Society of Anesthesiologists Physical Status Classification System class, total intraoperative IV fluids, and surgery duration were recorded, as well as, mean arterial pressure (MAP), end-tidal CO2, and end-tidal isoflurane concentration. Mean preinduction ONSD, in the 25 patients studied, was 4.5+0.5 mm and mean postoperative ONSD was 5.5+0.5 mm. Controlling for preinduction ONSD, postoperative ONSD was significantly associated with MAP (P=0.048) and the association of postoperative ONSD with end-tidal CO2 trended toward significance (P=0.072). This study demonstrates an increase in ONSD in patients undergoing RALRP. These findings confirm ICP rises to ≥20 mm Hg during RALRP surgery. This increase in ICP is significantly associated with increasing MAP. Patients with intracranial pathology should be counseled to the risks RALRP may pose with regard to intracranial hypertension.

Sonographic optic nerve sheath diameter as a surrogate measure for intracranial pressure in anesthetized patients in the Trendelenburg position

BackgroundIt remains to be elucidated whether the Trendelenburg position increases intracranial pressure (ICP). ICP can be evaluated by measuring the sonographic optic nerve sheath diameter (ONSD). We investigated the effect of the isolated Trendelenburg position on ONSD in patients undergoing robot-assisted laparoscopic radical prostatectomy. Additionally, we evaluated the effect of the Trendelenburg position combined with pneumoperitoneum on ONSD.MethodsTwenty-one patients scheduled for robot-assisted laparoscopic radical prostatectomy were enrolled. Sonographic ONSDs and hemodynamic parameters were measured at specific time points: in the supine position after induction of anesthesia, 3 min after the steep Trendelenburg position (35° incline), 3 min after the steep Trendelenburg position combined with pneumoperitoneum, and in the supine position after desufflation of the pneumoperitoneum.ResultsThe ONSD 3 min after the steep Trendelenburg position was significantly higher than that of the supine position after induction of anesthesia (5.1 ± 0.3 mm vs. 4.5 ± 0.4 mm). In addition, the ONSD 3 min after the steep Trendelenburg position combined with pneumoperitoneum was higher than that of the supine position after induction of anesthesia (4.9 ± 0.4 mm vs. 4.5 ± 0.4 mm). The ONSD in the supine position after desufflation of the pneumoperitoneum was similar to that in the supine position after induction of anesthesia.ConclusionsUse of the isolated steep Trendelenburg position, for even a short duration, increased the sonographic ONSD, providing a better understanding of the effect of only a transient steep Trendelenburg position on ONSD as a surrogate measure for ICP.

Effect of Cervical Sympathetic Block on Optic Nerve Sheath Diameter Measured by Ultrasonography

Optic nerve sheath diameter (ONSD) measurement using ocular ultrasonography was introduced as a non-invasive technique to assess intracranial pressure. We investigated changes in ONSD after cervical sympathetic block (CSB). Ultrasound-guided CSB was performed with a lateral approach at the C6 level in 35 patients. ONSD was measured before CSB and after checking for Horner's syndrome 15 minutes after CSB. The mean ONSD was significantly higher after CSB than before (5.15 ± 0.38 mm vs. 4.75 ± 0.32 mm, p < 0.001). A comparison of ONSDs between the blocked and non-blocked sides revealed that these values did not differ significantly between sides at baseline and after CSB. On the basis of these preliminary data, CSB caused an increase in ONSD in patients without intracranial pathology or neurologic disorders. Further larger and controlled studies of the effect of CSB on intracranial pressure in humans are needed to confirm our findings.

Correlation of optic nerve sheath diameter with intracranial pressure monitoring in patients with severe traumatic brain injury

Aims and objectivesTo assess the feasibility and reliability of using optic nerve sheath diameter (ONSD) as an objective measure of intracranial pressure (ICP) in patients of severe head injury. Methods and materialsThis prospective study was carried out in Neurosurgery ICU over a 3-month period (April–June 2012). All patients with severe traumatic brain injury (admission GCS ≤8) who had ICP monitoring using Codman® intraparenchymal transducer had serial bedside ONSD measurements taken by a single neurosurgeon using a 7.5 MHz linear probe on the same ultrasound machine (Sonosite Micromaxx®) were enrolled in the study. Patients with significant ocular trauma to either eye were excluded. ResultsA total of 20 patients were enrolled during the study period. The mean age was 27 years (range 2–43 years) with M:F ratio of 3:1 and mean GCS of 6 (range 4–8). The mean ONSD in patients with ICP >20 was 6.6 ± 0.45 mm as compared to 5.9 ± 0.57 mm in patients with ICP <20 (p = 0.028). The Pearson Correlation Coefficient between ONSD (average of both eyes) and ICP was 0.499 (p = 0.041). A cutoff of 6.3 mm detected ICP >20 mmHg with 100% sensitivity and 72.7% specificity. ConclusionONSD is a technically simple, non-invasive method of assessing ICP and correlates well with actual ICP in patients of severe traumatic brain injury. A cutoff of 6.3 mm can be used to plan therapeutic interventions when ICP monitoring is unavailable or contraindicated.

Dependence of the optic nerve sheath diameter on acutely applied subarachnoidal pressure - an experimental ultrasound study

To determine the distensibility and elastic characteristics of the optic nerve sheath for development of a basic understanding of ultrasound studies aimed to measure optic nerve sheath diameter (ONSD) for detection of acutely elevated intracranial pressure (ICP). Isolated human optic nerves preparations obtained from autopsies were submitted to predefined pressure alterations, and consecutive changes in ONSD were measured by B-scan ultrasound under defined conditions. Following submission to pressure, the diameter of the nerve sheath increased up to 140% of its baseline value. The increase (mean 1.97 mm, SD 0.52 mm) corresponded to the magnitude of pressure steps measured in the perineural subarachnoidal space (SAS). Similarly, the ONSD declined in each of the preparations within a few minutes after the optic nerve was decompressed. However, it did not reach its baseline value again when pressure loads of 45-55 mmHg or more had been applied. The elasticity of the anterior sheath of the optic nerve is sufficient for the detection of pressure changes in the SAS especially for upward pressure steps. This is basically important for the application of clinical monitoring of the sheath diameter to facilitate the identification of patients with elevated ICP non-invasively (screening). However, further implementation of this procedure in neurointensive care and emergency medicine has to consider that the sheath diameter reversibility may be impaired after episodes of prolonged intracranial hypertension and a model for hysteresis is proposed.

Optic nerve sheath diameter in normal-tension glaucoma patients

BackgroundTo report on the optic nerve sheath diameter (ONSD) in patients with normal-tension glaucoma (NTG) compared with controls without known optic nerve (ON) or intracranial disease.MethodsIn 18 patients with NTG...