A 20-year multicentre retrospective review of optic nerve sheath fenestration outcomes

Background

Optic nerve sheath fenestration (ONSF) longitudinal outcomes remain unclear and are vital in the assessment of vision failure in patients with raised intracranial pressure (ICP). Furthermore, limited observational data exists regarding its use in other causes of raised ICP.

Objective

To determine the efficacy and safety of ONSF for idiopathic intracranial hypertension (IIH), cerebral venous sinus thrombosis (CVST), and other indications.

Method

Multicentre study from a tertiary hospital and specialty eye referral hospital in Melbourne, Australia, from July 2000 to December 2020. A total of 116 eyes from 70 patients undergoing ONSF were retrospectively reviewed with patient demographics, surgery indications, visual acuity (VA), visual fields, fundus photos of optic discs, retinal nerve fibre layer (RNFL) thickness, average thickness of optic discs on optical coherence tomography (OCT), and complications recorded. Parametric tests were used to compare the treatment groups pre- and post-operatively.

Results

A total of 116 eyes from 70 patients underwent ONSF, which involved 92 eyes with IIH, 9 eyes with CVST, and 15 eyes with other aetiologies ('Other'). Post ONSF, there was a best corrected visual acuity (BCVA) improvement or stabilisation in 84% of patients in all groups, with 50% achieving a BCVA of 6/6 or better at the final follow-up. RNFL, visual fields, and fundus grades all trended towards improvement, with most improvement noted by day 360. Common complications included transient diplopia (n = 29, 25%) and worsening of visual function requiring further cerebrospinal fluid (CSF) diversion procedures (n = 20, 17%). Complications were most significant in the 'Other' group with 1/3 of eyes requiring further CSF diversion procedures.

Conclusion

Our data demonstrates effectiveness in the use of ONSF in papilloedema with visual failure due to IIH or CVST and when other CSF diversion procedures or medical therapies have failed.

Systematic scoping review of papilledema in vestibular schwannoma without hydrocephalus

BACKGROUND

Vestibular schwannoma is a common pathology encountered by neurosurgeons worldwide. Often vestibular schwannoma presents with obstructive hydrocephalus. Papilledema is present in 8% of the patients with vestibular schwannoma, primarily due to obstructive hydrocephalus. Hyperproteinorrhachia is believed to be responsible for papilledema in the absence of hydrocephalus in vestibular schwannoma. However, there is a paucity of literature on the mechanism of papilledema in vestibular schwannoma patients with hydrocephalus.

OBJECTIVE

The aim of this study was to conduct a scoping review of scientific literature on papilledema in vestibular schwannoma patients without hydrocephalus.

METHODS

Design: This was a systematic scoping review and critical appraisal. Literature Search from PubMed was done following PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) and Joanna Briggs Institute guidelines for conducting and reporting scoping reviews.

RESULTS

A total of seven studies, including eight patients, were identified for inclusion in the review. The studies were heterogeneous in terms of reporting for various variables. All the included studies were case reports, with the earliest publication in 1954 and the latest publication in 2020. The mean age of the patients in the included studies was 35 years, with a minimum age of 20 years and maximum age of 64 years. Approximately 62.5% were females, and 37.5% were males in the included study. Only three studies have studied cerebrospinal fluid (CSF) proteins levels in these patients.

CONCLUSIONS

There is paucity in literature and a lack of evidence to conclusively state hyperproteinorrhachia as an antecedent to the development of papilledema in vestibular schwannoma patients without hydrocephalus. Younger age and female gender are risk factors for developing papilledema in the absence of hydrocephalus in vestibular schwannoma patients. Brainstem compression due to the large size of vestibular schwannoma can still have a patent aqueduct of Sylvius and no obstruction to CSF flow. The development of papilledema in vestibular schwannoma is a complex interplay of multiple factors that must be studied comprehensively for complete understanding.

Efficacy of Optic Nerve Sheath Fenestration in Patients with Increased Intracranial Pressure

Objectives

To evaluate the effectiveness of optic nerve sheath fenestration (ONSF) on visual functions in patients with increased intracranial pressure (İİP).

Materials and Methods

The medical records of 24 eyes of 17 patients who had İİP due to idiopathic intracranial hypertension, cerebral venous sinus thrombosis, or intracranial cyst and underwent ONSF surgery to prevent visual loss were evaluated. Pre- and postoperative visual acuity, optic disc images, and visual field findings were reviewed.

Results

The mean age of the patients was 30.4±8.5 years, and 88.2% were female. The patients' mean body mass index was 28.67±6.1 kg/m². The mean follow-up time was 24±12.1 months (range: 3-44). At postoperative 3 months, the mean best-corrected distance visual acuity had improved in 20 eyes (83.3%) and stabilized in 4 eyes (16.7%) compared to preoperative values. In visual field mean deviation, an improvement was observed in 10 eyes (90.9%), while 1 eye (9.1%) eye remained stable. Optic disc edema decreased in all patients.

Conclusion

This study indicates that ONSF has beneficial effects on visual function in patients with rapidly progressive visual loss caused by increased intracranial pressure.

Optic nerve sheath fenestration for visual impairment in cerebral venous diseases

Objective

Visual impairment is the most common clinical feature of cerebral venous sinus occlusion or cerebral venous thrombosis-induced intracranial hypertension, which can result in optic atrophy, leading to irreversible vision loss, visual field defections, and finally, permanent blindness. Papilledema is a typical early pathophysiological alteration in visual impairment. Optic nerve sheath fenestration (ONSF) has become increasingly accepted as an option to prevent or halt progressive visual loss owing to its low risk and complications. The objective of this study is to review the latest research progress on ONSF for the treatment of visual impairment related to cerebral venous diseases.

Methods

Study were searched following PRISMA guidelines based on three electronic databases (Pubmed, Embase and Medline-Ovid). We used the following keywords and variations as keywords to identify studies: "optic nerve sheath fenestration, papilledema, cerebral venous diseases, cerebral venous stenosis, cerebral venous thrombosis, idiopathic intracranial hypertension". The publication date of studies was restricted between 1,872.1.1 and 2,021.12.31. The application of ONSF in papilledema due to cerebral venous diseases is reviewed. Additionally, the common surgical approaches as well as advantages and disadvantages are also described graphically.

Results

With the improvement of specific details of the ONSF procedure and surgical instruments, complications of ONSF have reduced and its safety has been significantly improved, although the number of clinically investigated cases in the literature remains low.

Conclusion

We recommend that ONSF should be considered as an imperative alternative to reduce or delay the visual morbidity of cerebral venous diseases, although there is yet no consensus on the optimal surgical timing.

Visual recovery after unilateral optic nerve sheath fenestration for pseudotumor cerebri syndrome

PURPOSE

To evaluate the effect of optic nerve sheath fenestration (ONSF) on the rate of visual function improvement in patients with pseudotumor cerebri syndrome (PTCS).

METHODS

Retrospective chart review of patients with PTCS who underwent ONSF between 1998 and 2017. Visual function was evaluated by evaluating visual field (VF), mean deviation (MD), retinal nerve fiber layer (RNFL) thickness, papilledema grade, and visual acuity (VA) prior to and after ONSF.

RESULTS

Seventeen female patients aged 17 to 36 years underwent unilateral ONSF. Follow-up averaged 40.1 months. VF MD improved steadily in both eyes up to 12 months. Average RNFL thickness improved in the operated eye from 347 ± 166 mm to 92 ± 27 mm (p < .001) and the non-operated eyes from 306 ± 165 mm to 109 ± 46 mm (p < .001). The grade of papilledema improved in the operated eye from 3.3 ± 1.3 to 0.3 ± 0.7 and the non-operated eye from 3.0 ± 1.6 to 0.18 ± 0.4. There was an exponential rate of improvement in papilledema and RNFL thickness, with the greatest improvement occurring within the first 30 days. Average visual acuity remained intact in both eyes before and after surgery.

CONCLUSIONS

ONSF in appropriately selected patients leads to rapid improvement in papilledema and a steady recovery in VF.

Recovery of Vision after Optic Nerve Sheath Fenestration in Children and Adolescents with Elevated Intracranial Pressure

PURPOSE

To evaluate the effect of optic nerve sheath fenestration (ONSF) on the recovery of visual function in pediatric patients with optic disc swelling owing to increased intracranial pressure.

DESIGN

Retrospective case series.

METHODS

Medical chart review of all pediatric patients who underwent ONSF between 2009 and 2020 at the Children's Hospital of Philadelphia. Visual function was assessed at pre and postoperative visits. The main outcome measures were visual acuity, color vision, extraocular motility, visual field mean deviation, retinal nerve fiber layer thickness measured by optical coherence tomography.

RESULTS

Fourteen pediatric patients (10 females; mean ± SD age of 14 ± 2.6 years; range, 8.5-17.5 years) were included. Five patients underwent bilateral surgeries. Ten patients were diagnosed with idiopathic intracranial hypertension. Of the 10 idiopathic intracranial hypertension patients, 3 had a previous history of weight gain and 2 of systemic steroid treatment; these can be referred to as pseudotumor cerebri. The mean ± SD follow-up length was 16.4 ± 12.3 months. VA improved from 20/138 to 20/68 in the operated eye (P = .0003) and from 20/78 to 20/32 in the nonoperated eye (P = .02). Color vision improved in the operated eye (P = .04), extraocular motility improved in the operated and nonoperated eye (P = .002 and P = .04 respectively). Visual field mean deviation improved in the operated (-23.4 dB to -11.5 dB, P < .0001) and nonoperated eye (-19.8 dB to -6.8 dB, P = .02). Retinal nerve fiber layer thickness improved in the operated eye (349.1 to 66.2 µm; P < .0001). The postoperative improvement was observed as early as the postoperative day 1.

CONCLUSIONS

ONSF produces a rapid and persistent vision improvement in both the operated eye and the nonoperated eye. In children and young adults with papilledema and elevated intracranial pressure causing vision loss that is severe at presentation or refractory to standard medical management, ONSF should be considered.

Idiopathic Intracranial Hypertension - Challenges and Pearls

Idiopathic intracranial hypertension (IIH) is defined as a syndrome of raised intracranial pressure with normal imaging of the brain and cerebrospinal fluid (CSF) composition. There is a rising incidence and prevalence of this disease related to the increased prevalence of obesity. It typically affects women of working age, and headache is the predominant morbidity in over 90%. The disease is also more prevalent in young males. There are many controversies and myths that surround IIH. There are currently few treatment options for IIH, management is typically medical with those experiencing progressive visual loss undergoing surgical procedures. Weight loss and venous sinus stenting are a few therapies directed at the etiology.

Unilateral Optic Nerve Sheath Fenestration in Idiopathic Intracranial Hypertension: A 6-Month Follow-Up Study on Visual Outcome and Prognostic Markers

Loss of vision is a feared consequence of idiopathic intracranial hypertension (IIH). Optic nerve sheath fenestration (ONSF) may be an effective surgical approach to protect visual function in medically refractory IIH. In this study, we evaluate the impact of unilateral superomedial transconjunctival ONSF on bilateral visual outcome using a comprehensive follow-up program. A retrospective chart review of IIH patients who underwent unilateral ONSF between January 2016 and March 2021 was conducted. Patients fulfilling the revised Friedman criteria for IIH and who had exclusively received ONSF as a surgical treatment were included. Main outcomes were visual acuity (VA); perimetric mean deviation (PMD); papilledema grade; and optic nerve head elevation (maxONHE) 1 week, 2 weeks, and 1, 3, and 6 months after surgery. VA (p < 0.05), PMD (p < 0.05), papilledema grade (p < 0.01), and maxOHNE (p < 0.001) were improved after 6 months on both the operated and non-operated eye. Prolonged surgical delay impedes PMD improvement (r = -0.78, p < 0.01), and an increasing opening pressure initiates a greater ganglion cell loss (r = -0.79, p < 0.01). In this small case series, we demonstrate that unilateral superonasal transconjunctival ONSF is a safe procedure with an effect on both eyes. Optic nerve head elevation and PMD are feasible biomarkers for assessing early treatment efficacy after ONSF.

Management of Idiopathic Intracranial Hypertension During the COVID-19 Pandemic

BACKGROUND

In the current coronavirus disease 2019 (COVID-19) pandemic, health systems are struggling to prioritize care for affected patients; however, physicians globally are also attempting to maintain care for other less-threatening medical conditions that may lead to permanent disabilities if untreated. Idiopathic intracranial hypertension (IIH) is a relatively common condition affecting young females that could lead to permanent blindness if not properly treated. In this article, we provide some insight and recommendations regarding the management of IIH during the pandemic.

METHODS

The diagnosis, follow-up, and treatment methods of IIH during the COVID-19 pandemic period are reviewed. COVID-19, as a mimic of IIH, is also discussed.

RESULTS

Diagnosis and follow-up of papilledema due to IIH during the COVID-19 pandemic can be facilitated by nonmydriatic fundus photography and optical coherence tomography. COVID-19 may mimic IIH by presenting as cerebral venous sinus thrombosis, papillophlebitis, or meningoencephalitis, so a high index of suspicion is required in these cases. When surgical treatment is indicated, optic nerve sheath fenestration may be the primary procedure of choice during the pandemic period.

CONCLUSION

IIH is a serious vision-threatening condition that could lead to permanent blindness and disability at a relatively young age if left untreated. It could be the first presentation of a COVID-19 infection. Certain precautions during the diagnosis and management of this condition could be taken that may allow appropriate care to be delivered to these patients while minimizing the risk of coronavirus infection.

Optic nerve sheath fenestration for visual rehabilitation in moyamoya disease

A 13-year-old female presented with decrease in vision in both eyes with headache and vomiting for 15 days. Her visual acuity was perception of light with inaccurate projection in the right eye and counting fingers close to face in the left eye. Pupils were nonreactive. Fundus showed bilateral disc edema. Magnetic resonance angiography showed an attenuated caliber of the left internal carotid artery with occlusion of the left middle cerebral artery with collaterals, characteristic of moyamoya disease. The patient underwent right optic nerve sheath fenestration, following which her vision improved to 6/36 in the right and 6/24 in the left eye. Moyamoya disease is an occlusive disease of the cerebral vasculature most commonly seen in the Japanese. Children usually present with ischemic events. In the literature, visual symptoms secondary to raised intracranial tension in moyamoya disease are not well described. Ophthalmologists should be aware of this disease and the treatment options for salvaging vision.

Extensive Cerebral Venous Sinus Thrombosis Due to Medroxyprogesterone Acetate

This retrospective patient report describes a unique case of cerebral venous sinus thrombosis arising from hormonal contraceptive use, and the management of said thrombosis and its secondary ophthalmic manifestations. The patient initially presented with significant visual decline, headaches, florid disc oedema, and vessel tortuosity, due to extensive sinus thromboses that were causing increased intracranial pressure. It was determined that the root cause of the thrombosis was the use of injectable medroxyprogesterone acetate, leading to a hypercoagulable state. Optic nerve sheath fenestration was performed for this patient as an early intervention. The patient, though ultimately experiencing some vision loss, was able to recover and retain limited unilateral central vision, despite a protracted hospital course. We hope to propose that optic nerve sheath fenestration, in conjunction with anti-coagulation therapy, may be a consideration for patients with similar presentations on an individualised basis, in order to prevent vision loss from cerebral venous sinus thrombosis. Though studies are limited, we believe early intervention may be what allowed our patient to retain some central vision, and suggest more studies be done into the utility of this procedure for patients with this clinical vignette.

Outcomes of optic nerve sheath fenestration from superomedial eyelid crease approach

Purpose: The purpose of this study is to report the safety and outcomes of optic nerve sheath fenestration (ONSF) performed via superomedial eyelid crease approach.Methods: A retrospective chart review was performed on patients undergoing superomedial eyelid crease ONSF at a single institution between 2014-2019. Data obtained included preoperative visual acuity (VA), mean deviation (MD) on visual field (VF), papilledema grade, intraoperative time, estimated blood loss, intraoperative complications and optic nerve sheath biopsy results. Postoperative month 6 (POM6) data collected included VA, MD, papilledema grade, and lid contour. Outcome measures included overall change in VA, MD, and papilledema grade at POM6. Statistical analysis was performed using STATA version 16 statistical software. Data analysis was done comparing all patients pre- and postoperatively. Additional subgroup analysis was performed on patients undergoing ONSF for IIH vs other indications, and on the contralateral unoperated eye.Results: A total of 31 eyes of 24 patients were identified, four of whom were excluded due to being lost to follow-up. At POM6, improvement was seen in VA (p<0.001) across all groups. There was improvement in POM6 median papilledema grade and MD, but these did not reach statistical significance. Additional subgroup analysis on patients with IIH showed statistically significant improvement in POM 6 VA (p=0.009), papilledema (p=0.009) and MD (p<0.001), as well as VA improvement in the contralateral unoperated eye (p<0.001).Conclusions: Superomedial eyelid crease approach for ONSF is a safe and effective surgery in IIH and other conditions of excess pressure within the optic nerve sheath.

Peripapillary microperimetry for the diagnosis and follow-up of papilledema in cases treated for idiopathic intracranial hypertension

OBJECTIVES

To evaluate the use of peripapillary microperimetry in the diagnosis and follow-up of medically and surgically treated cases of papilledema due to idiopathic intracranial hypertension (IIH).

METHODS

This study was a prospective non-comparative observational case series of patients with IIH. All patients underwent full ophthalmological examination, radiological imaging, and lumbar puncture, as well as microperimetric measurements around the optic nerve head. Patients were classified into a medical group, treated by weight reduction and acetazolamide, and a surgical group, treated by optic nerve sheath fenestration. Peripapillary microperimetric examinations were done at presentation and after one-month of treatment. Findings were compared to values obtained from an age-matched healthy control group.

RESULTS

The study included 78 eyes of 39 patients diagnosed with IIH and 32 eyes of 16 healthy control subjects. The average of the sum of the 12 peripapillary microperimetric thresholds for both eyes of IIH cases before treatment was 53.4±59.9 dB, while for controls it was 171±14.0 dB (p<0.001). After 1 month of treatment, it improved to 86.7±56.1 dB (p<0.001) in IIH cases. Analyzed separately, the medical group improved from 68.9±43.4 dB to 105.2±76.5 dB (p<0.001), while the surgical group improved from 13.5±21.9 dB to 54.9±35.5 dB (p<0.001). Several potential roles for peripapillary microperimetry use in IIH management were identified including confirming papilledema diagnosis, follow up of treatment, and selection of cases for surgery.

CONCLUSION

Microperimetry can accurately and quantitatively monitor changes in peripapillary retinal sensitivity in patients undergoing treatment for papilledema due to IIH.

Transient vision loss after optic nerve sheath fenestration

Optic nerve sheath fenestration (ONSF) is a well-known, relatively safe, and effective surgical treatment for visual loss related to papilledema. Visual loss following ONSF is uncommon but can occur from direct surgical trauma, ischemic optic neuropathy, orbital or intrasheath hemorrhage, or arterial occlusion. Transient severe (e.g., light perception (LP) or no light perception (NLP) visual loss) after ONSF is uncommon but has been reported. We describe a case of LP vision following uncomplicated ONSF with orbital imaging demonstrating significant postoperative inflammation and slow recovery after intravenous steroid treatment. We discuss the various mechanisms for this phenomenon after ONSF. To our knowledge, this is the first clinico-radiologic description with follow up and recovery of this postoperative complication of ONSF to be reported in the English language ophthalmic literature.

Understanding the complex pathophysiology of idiopathic intracranial hypertension and the evolving role of venous sinus stenting: a comprehensive review of the literature

Idiopathic intracranial hypertension (IIH) is a disease defined by elevated intracranial pressure without established etiology. Although there is now consensus on the definition of the disorder, its complex pathophysiology remains elusive. The most common clinical symptoms of IIH include headache and visual complaints. Many current theories regarding the etiology of IIH focus on increased secretion or decreased absorption of cerebrospinal fluid (CSF) and on cerebral venous outflow obstruction due to venous sinus stenosis. In addition, it has been postulated that obesity plays a role, given its prevalence in this population of patients. Several treatments, including optic nerve sheath fenestration, CSF diversion with ventriculoperitoneal or lumboperitoneal shunts, and more recently venous sinus stenting, have been described for medically refractory IIH. Despite the availability of these treatments, no guidelines or standard management algorithms exist for the treatment of this disorder. In this paper, the authors provide a review of the literature on IIH, its clinical presentation, pathophysiology, and evidence supporting treatment strategies, with a specific focus on the role of venous sinus stenting.

Contemporary management of the pseudotumor cerebri syndrome

Introduction: Diagnosis and appropriate management of patients with the pseudotumor cerebri syndrome are imperative to prevent or minimize permanent visual loss and headache-related disability. Areas covered: Steps in management, including making the correct diagnosis, techniques to assess the patient's visual status, medical treatment of intracranial hypertension and the associated headaches, weight management strategies, surgical treatments and stenting are reviewed incorporating the most recent medical evidence. Expert opinion: As the pathogenesis of the pseudotumor cerebri syndrome is still unknown, many of the currently employed management strategies incorporate a 'plumbing approach' to decrease cerebrospinal fluid (CSF) pressure. The Idiopathic Intracranial Hypertension Trial (IIHTT) taught us that the disorder markedly affects visual and overall quality of life, and that reducing pressure alone is not enough to make patients well, even those considered to have 'mild' vision loss. Other than the IIHTT, the evidence supporting the use of various treatments is meager. The course of the disorder can be unpredictable, and the clinician(s) managing these patients are often uncertain about which treatments to employ. Moreover, the desired modalities and specialists are not universally available in all locations. An individualized and detailed approach to the various manifestations and nuances of the disorder is essential.

Optic nerve sheath fenestration: a revised lateral approach for nerve access

Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, describes a disease of poorly understood pathophysiology with a specific set of signs and symptoms including potentially irreversible and blinding visual loss. Optic nerve sheath fenestration (ONSF) is a well-described surgical treatment for patients with IIH and progressive visual loss despite maximally tolerated medical therapy. A number of optic nerve access procedures have been described including medial transconjunctival, superomedial lid crease, and lateral orbitotomy with and without bone takedown. The purpose of this report is to describe a revised lateral approach for temporal optic nerve access that obviates the need to traverse through the intraconal fat of the central surgical space in the previously described lateral approach techniques.

A 15-year review of secondary and tertiary optic nerve sheath fenestration for idiopathic intracranial hypertension

PURPOSE

Optic nerve sheath fenestration (ONSF) is a common surgical option for patients with idiopathic intracranial hypertension (IIH) with vision loss refractory to medical management. Little is known about the visual benefit of repeated ONSF. The authors aimed to assess the efficacy of secondary and tertiary ONSF in patients with IIH.

METHODS

A retrospective chart review was performed on all patients with repeat ONSF for IIH at Emory University from 1999 to 2016. Primary outcome measures included visual acuity, optic nerve head findings, and visual field results.

RESULTS

A total of nine eyes in seven patients (five females and two males) with repeat ONSF were identified. Two of the seven patients had repeat ONSF in both eyes, while the remaining five patients had only one eye repeated. Five of seven patients (five eyes) improved or remained stable after the secondary ONSF. Two patients (three eyes) continued to worsen despite the secondary fenestration surgery and underwent tertiary ONSF at an average of 13.2 months (SD 5.5 months) after the failed secondary ONSF. Both patients that underwent the tertiary fenestration showed improvement. Six of the patients had either improvement or stability in their clinical findings at their last documented follow-up, but one continued to worsen despite intervention.

CONCLUSIONS

This study suggests that secondary and tertiary nerve sheath fenestration is a viable management option for patients with progressive vision loss from IIH. Repeat ONSFs do not appear to have increased complication or failure rates compared to prior documented studies regarding primary fenestrations.

Visual Function Improvement After Optic Nerve Sheath Fenestration in Osteopetrosis Patients with Optic Canal Stenosis: A Report of Two Cases

The outcome of two patients with visual loss from osteopetrosis who underwent an optic nerve sheath fenestration (ONSF) is reported. A 20-year-old male and 26-year-old female with osteopetrosis had optic nerve edema. Computed tomography and magnetic resonance imaging demonstrated optic canals stenosis. Both patients underwent unilateral ONSF. After ONSF, the patients experienced improvement in visual acuity and optic nerve appearance. Therefore, when papilledema is recognized in osteopetrosis patients, it may be reasonable to start with an ONSF even if the optic canal seems to be stenotic because of the lower morbidity that is associated with this procedure compared with other surgical options.

Optociliary Shunt Vessels: Role in Diagnosis and Treatment of Atypical Pseudotumor Cerebri

A 46-year-old man presented with severe visual loss and optic atrophy associated with optociliary shunt vessels. The diagnostic work-up revealed intracranial hypertension and cerebral venous sinus stenosis, with no evidence of previous thrombosis. In view of the severe visual dysfunction, both eyes were submitted to optic nerve sheath fenestration. After surgery, a regression of collateral vessels was observed in both eyes.

Visual outcomes following optic nerve sheath fenestration via the medial transconjunctival approach

This article determines the safety of optic nerve sheath fenestration (ONSF) for the treatment of patients with intracranial hypertension in the immediate 6-month post-operative period and its efficacy in reducing optic disk edema. Retrospective, non-comparative interventional case series. 207 eyes in 104 patients undergoing ONSF between the years 2005 and 2014. Papilledema grade based on modified Frisen scale and mean deviation of Humphrey visual field. 207 eyes of 104 patients (102 IIH, 2 IH due to dural sinus thrombosis) were included in the study. The patients were 96.1% female (N = 100) and 3.9% male (N = 4). The average patient age was 28.8 years (SD ± 9.5 years) and had a mean opening pressure of 39.85 cmH2O (SD ± 8.4 cmH2O). Mean follow-up period was 6.0 months (SD ± 5.9 months). Papilledema resolved in 76.1% of eyes at 1 week (N = 102 eyes), 75% of eyes at 1 month (N = 90 eyes), and 71% of eyes at 6 months (N = 94 eyes). Visual field comparison had a mean of the paired differences in MD at 1 week, 1 month, and 6 months of 1.59dB (P = 0.006), 2.53dB (P < 0.001), and 1.30dB (P = 0.016), respectively. ONSF is effective in reducing optic disk edema and does not cause vision loss in the 6-month post-operative period regardless of severity of IIH (as judged by elevation of opening pressure measured at pre-operative assessment).

Effect of optic nerve sheath fenestration for idiopathic intracranial hypertension on retinal nerve fiber layer thickness

The objective of the study was to evaluate whether optic nerve sheath fenestration in patients with idiopathic intracranial hypertension was associated with improvement in visual field pattern deviation and optical coherence tomography retinal nerve fiber layer thickness.The records of 13 eyes of 11 patients who underwent optic nerve sheath fenestration were reviewed. The subjects were patients of a clinical practice in Dallas, Texas. Charts were reviewed for pre- and postoperative visual field pattern deviation (PD) and retinal nerve fiber layer thickness (RNFL).PD and RNFL significantly improved after surgery. Average PD preoperatively was 8.51 DB and postoperatively was 4.80 DB (p = 0.0002). Average RNFL preoperatively was 113.63 and postoperatively was 102.70 (p = 0.01). The preoperative PD and RNFL did not correlate strongly.Our results demonstrate that PD and RNFL are improved after optic nerve sheath fenestration. The pre- and postoperative RNFL values were compared to the average RNFL value of healthy optic nerves obtained from the literature. Post-ONSF RNFL values were significantly closer to the normal value than preoperative. RNFL is an objective parameter for monitoring the optic nerve after optic nerve sheath fenestration. This study adds to the evidence that OCT RNFL may be an effective monitoring tool for patients with IIH and that it continues to be a useful parameter after ONSF.

Idiopathic intracranial hypertension: ongoing clinical challenges and future prospects

Idiopathic intracranial hypertension (IIH) is an uncommon disorder characterized by increased intracranial pressure without radiological or laboratory evidence of intracranial pathology except empty sella turcica, optic nerve sheath with filled out cerebrospinal fluid spaces, and smooth-walled nonflow-related venous sinus stenosis or collapse. This condition typically affects obese women. The incidence of IIH is increasing with the rising prevalence of obesity. Persistent headache is the most common symptom. Visual impairment is a serious complication that may not be recognized by the patients. This paper reviews clinical manifestations, diagnostic challenges, and current treatments of IIH in adults. Various imaging modalities have been studied on their validity for detection of IIH and papilledema. This review also includes new studies on medical, surgical, and interventional management of this condition. Acetazolamide and topiramate are the only two medications that have been studied in randomized controlled trials about their efficacy in treatment of IIH. In patients who have severe visual impairment or progressive visual deterioration despite medical management, surgical or interventional treatment may be considered. The efficacy and complications of cerebrospinal fluid diversion, optic nerve sheath fenestration, and endovascular venous stenting reported in the last 3 decades have been summarized in this review. Finally, the prospective aspects of biomarkers and treatments are proposed for future research.

Papilledema: epidemiology, etiology, and clinical management

Papilledema is optic disc swelling due to high intracranial pressure. Possible conditions causing high intracranial pressure and papilledema include intracerebral mass lesions, cerebral hemorrhage, head trauma, meningitis, hydrocephalus, spinal cord lesions, impairment of cerebral sinus drainage, anomalies of the cranium, and idiopathic intracranial hypertension (IIH). Irrespective of the cause, visual loss is the feared morbidity of papilledema, and the main mechanism of optic nerve damage is intraneuronal ischemia secondary to axoplasmic flow stasis. Treatment is directed at correcting the underlying cause. In cases where there is no other identifiable cause for intracranial hypertension (ie, IIH) the available options include both medical and surgical modalities. Weight loss and diuretics remain the mainstays for treatment of IIH, and surgery is typically reserved for patients who fail, are intolerant to, or non-compliant with maximum medical therapy.

Long-Term Results of Optic Nerve Sheath Fenestration for Idiopathic Intracranial Hypertension: Earlier Intervention Favours Improved Outcomes

The role of optic nerve sheath fenestration (ONSF) in the management of idiopathic intracranial hypertension remains controversial, with indications, risks, and benefits compared to cerebro-spinal fluid diversion procedures not fully elucidated. We report a retrospective record review of 37 patients (50 eyes) which had undergone ONSF by a single surgeon. Visual acuity (VA) improved in 22% of operated eyes and 17% of fellow eyes; stabilized in 54% of operated and 74% of fellow eyes; and deteriorated in 24% of operated and 9% of fellow eyes. Better pre-operative VA (p = 0.01), colour vision (p = 0.002), and earlier intervention (p = 0.04) were associated with stabilization. We conclude that ONSF often stabilizes vision and visual fields. Our results were best in patients with better pre-operative vision and in those with earlier intervention.

An update on idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology often encountered in neurologic practice. It produces nonlocalizing symptoms and signs of raised intracranial pressure and, when left untreated, can result in severe irreversible visual loss. It most commonly occurs in obese women of childbearing age, but it can also occur in children, men, nonobese adults, and older adults. Although it is frequently associated with obesity, it can be associated with other conditions, such as obstructive sleep apnea and transverse cerebral venous sinus stenoses. Recent identification of subgroups at high risk for irreversible visual loss, including black patients, men, and patients with fulminant forms of IIH, help guide the optimal management and follow-up. Ongoing studies of venous anatomy and physiology in IIH patients, as well as a recently begun randomized clinical treatment trial, should provide further insight into this common yet poorly understood syndrome.