Measurement and Relationship of Subarachnoid Pressure of the Optic Nerve to Intracranial Pressures in Fresh Cadavers

Liu, Don; Kahn, Mon-Te

doi:10.1016/s0002-9394(14)73195-2

Cited by 189 publications

(141 citation statements)

References 21 publications

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“…Because of the influence of the measuring process itself pressure measurements in small and non-homogeneous compartments are technically diffcult to perform and the measurements are not necessarily reliable (personal experience) although other groups published their results with more confidence. 13 Our morphological study of trabeculae and septa within the subarachnoid space of the optic nerve provides strong anatomical evidence that the hydrodynamics between and within the different cerebrospinal fluid segments, especially within the subarachnoid space of the optic nerve, is more complex than within the ideal Bernoulli tube. Cerebrospinal fluid dynamics should therefore not simply be regarded as an undeflected continuum in a series of interconnecting chambers.…”

Section: Discussionmentioning

confidence: 82%

“…In a paper dedicated to cerebrospinal fluid pressure in the subarachnoid space of the optic nerve, Liu suggested that the majority of trabeculae occur in the mid-orbital segment of the intraorbital portion. 13 Neither Hayreh's nor Liu's study, however, provide histological evidence that would support their assumptions. Concerning the architecture and location of the trabeculae and septa, our study shows that the subarachnoid space narrows in the mid-orbital segment where the delicate character of the trabeculae changes gradually into broader septa and stout pillars that subdivide the subarachnoid space into small compartments.…”

Section: Discussionmentioning

confidence: 86%

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Architecture of arachnoid trabeculae, pillars, and septa in the subarachnoid space of the human optic nerve: anatomy and clinical considerations

Killer

Laeng²,

Flammer³

et al. 2003

British Journal of Ophthalmology

301

214

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Aims: To describe the anatomy and the arrangement of the arachnoid trabeculae, pillars, and septa in the subarachnoid space of the human optic nerve and to consider their possible clinical relevance for cerebrospinal fluid dynamics and fluid pressure in the subarachnoid space of the human optic nerve. Methods: Postmortem study with a total of 12 optic nerves harvested from nine subjects without ocular disease. All optic nerves used in this study were obtained no later than 7 hours after death, following qualified consent for necropsy. The study was performed with transmission (TEM) and scanning electron microscopy (SEM). Results: The subarachnoid space of the human optic nerve contains a variety of trabeculae, septa, and stout pillars that are arranged between the arachnoid and the pia layers of the meninges of the nerve. They display a considerable numeric and structural variability depending on their location within the different portions of the optic nerve. In the bulbar segment (ampulla), adjacent to the globe, a dense and highly ramified meshwork of delicate trabeculae is arranged in a reticular fashion. Between the arachnoid trabeculae, interconnecting velum-like processes are observed. In the mid-orbital segment of the orbital portion, the subarachnoid space is subdivided, and can appear even loosely chambered by broad trabeculae and velum-like septa at some locations. In the intracanalicular segment additionally, few stout pillars and single round trabeculae are observed. Conclusion: The subarachnoid space of the human optic nerve is not a homogeneous and anatomically empty chamber filled with cerebrospinal fluid, but it contains a complex system of arachnoid trabeculae and septa that divide the subarachnoid space. The trabeculae, septa, and pillars, as well as their arrangement described in this study, may have a role in the cerebrospinal fluid dynamics between the subarachnoid space of the optic nerve and the chiasmal cistern and may contribute to the understanding of the pathophysiology of asymmetric and unilateral papilloedema. All the structures described are of such delicate character that they can not even be visualised with high resolution magnetic resonance imaging (MRI).T he optic nerve is a white matter tract of the central nervous system that extents through the optic canal into the orbit. It is enveloped by the meninges and is surrounded by cerebrospinal fluid that enters the subarachnoid space via the chiasmal cistern.Anatomically the nerve can be divided into orbital and intracanalicular portions. The widest part of the orbital portion is adjacent to the ocular globe and is called the bulbar segment. It is followed by the mid-orbital segment (Fig 1).Although many studies on the cranial meninges are available, relatively few deal exclusively with the meninges of the optic nerve and the structures, such as trabeculae and septa, within its subarachnoid space. Anderson described arachnoid trabeculae stretching between the arachnoid layer and the pia layer in the subarachnoid space in the optic...

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Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 86%

Architecture of arachnoid trabeculae, pillars, and septa in the subarachnoid space of the human optic nerve: anatomy and clinical considerations

Killer

Laeng²,

Flammer³

et al. 2003

British Journal of Ophthalmology

301

214

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“…1). The ONSD is calculated perpendicular to the vertical axis of the scanning place 3 mm behind the globe, where the ON sheath structure is more prone to expansion due to increases in ICP [11], probably Fig. 1 Optic nerve sonography.…”

Section: Experimental Designmentioning

confidence: 99%

Intraocular pressure correlates with optic nerve sheath diameter in patients with normal tension glaucoma

Pinto

Vandewalle

Pronk

et al. 2011

Graefes Arch Clin Exp Ophthalmol

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Purpose 1. Identify differences in optic nerve sheath diameter (ONSD) as an indirect measure of intracranial pressure (ICP) in glaucoma patients and a healthy population. 2. Identify variables that may correlate with ONSD in primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG) patients. Methods Patients with NTG (n046) and POAG (n061), and healthy controls (n042) underwent B-scan ultrasound measurement of ONSD by an observer masked to the patient diagnosis. Intraocular pressure (IOP) was measured in all groups, with additional central corneal thickness (CCT) and visual field defect measurements in glaucomatous patients. Only one eye per patient was selected. Kruskal-Wallis or Mann-Whitney were used to compare the different variables between the diagnostic groups. Spearman correlations were used to explore relationships among these variables. Results ONSD was not significantly different between healthy, NTG and POAG patients (6.09±0.78, 6.03±0.69, and 5.71±0.83 respectively; p00.08). Visual field damage and CCT were not correlated with ONSD in either of the glaucoma groups (POAG, p00.31 and 0.44; NTG, p00.48 and 0.90 respectively). However, ONSD did correlate with IOP in NTG patients (r00.53, p<0.001), while it did not in POAG patients and healthy controls (p00.86, p00.46 respectively). Patient's age did not relate to ONSD in any of the groups (p>0.25 in all groups). Conclusions Indirect measurements of ICP by ultrasound assessment of the ONSD may provide further insights into the retrolaminar pressure component in glaucoma. The correlation of ONSD with IOP solely in NTG patients suggests that the translaminar pressure gradient may be of particular importance in this type of glaucoma.

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“…However, accurate direct measurement of intrasheath CSF pressure in vivo has yet to be achieved and so the question of continuing CSF leak into the orbit remains speculative. [3][4][5] ONSD for visual failure associated with raised intracranial pressure Resolution of papilloedema is often, but not always, accompanied by improvement in the visual field and acuity. Numerous reports have testified to the role of ONSD for papilloedema when visual function fails and medical measures are inadequate to restore or stabilise vision.…”

Section: Pathophysiologymentioning

confidence: 99%

Optic nerve disorders: role of canal and nerve sheath decompression surgery

Acheson

2004

Eye

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Optic nerve sheath decompression (ONSD) maintains a role in the management of visual loss complicating papilloedema in selected patients primarily with idiopathic intracranial hypertension. The evidence base for this intervention is reviewed and audit data on visual outcomes for patients with acute, chronic, and atrophic forms of papilloedema are contrasted. Optic canal decompression has a role in the management of compressive optic neuropathies complicating mass lesions arising from paranasal sinuses and intracranially and can be achieved by transethmoidal, transbasal, and open craniotomy routes. The evidence base supporting this intervention in traumatic optic neuropathy and in primary bone disease causing canal stenosis (in particular fibrous dysplasia) is reviewed where the indications are more controversial.

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Measurement and Relationship of Subarachnoid Pressure of the Optic Nerve to Intracranial Pressures in Fresh Cadavers

Cited by 189 publications

References 21 publications

Architecture of arachnoid trabeculae, pillars, and septa in the subarachnoid space of the human optic nerve: anatomy and clinical considerations

Architecture of arachnoid trabeculae, pillars, and septa in the subarachnoid space of the human optic nerve: anatomy and clinical considerations

Intraocular pressure correlates with optic nerve sheath diameter in patients with normal tension glaucoma

Optic nerve disorders: role of canal and nerve sheath decompression surgery

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