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

Optic nerve sheath decompression saves sight in severe papilloedema: results from 81 eyes in 56 patients with pseudotumor cerebri

PURPOSE

To report the outcome of optic nerve sheath decompression (ONSD) for papilloedema in a teaching hospital in western Turkey.

METHODS

The charts of 56 patients who had ONSD surgery between April 2007 and September 2019 were collated; and a total of 81 operated and 31 fellow eyes were included. Pre- and postoperative ophthalmologic examination including best-corrected visual acuity (BCVA), colour vision (CV), visual field (VF) analysis, fundoscopic examination and demographic and medical characteristics of the patients were noted and outcomes after surgery were investigated.

RESULTS

Of all study eyes, 49 (43.7%) eyes had BCVA 0.2 or less and 62 (55.3%) eyes had mean deviation (MD) below - 20.0 dB. 62 (55.3%) eyes had Frisen grade 4 or 5 papilloedema. Almost half of the eyes had severe vision loss. After ONSD, BCVA, CV and MD in both operated and fellow non-operated eyes improved significantly (p < 0.001, p = 0.009 and p < 0.001 for operated, p < 0.001, p = 0.007 and p < 0.001 for fellow eyes, respectively). Earlier surgery and higher cerebrospinal fluid opening pressure were related to better outcomes. None of the patients had major operative complications.

CONCLUSION

Optic nerve sheath decompression can safely improve vision not only of the operated but also of the non-operated eye, even in cases with severe vision loss from severe bilateral papilloedema. Regardless of initial VA and VF, patients may benefit from ONSD; the earlier it is done the more likely the better outcome.

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.

A 270-Degree Decompression of Optic Nerve in Refractory Idiopathic Intracranial Hypertension Using an Ultrasonic Aspirator - A Prospective Institutional Study

Background

Although the nonsurgical treatment for idiopathic intracranial hypertension (IIH) involves weight loss, diuretics, and steroids, surgical intervention is required if there is a worsening of symptoms or visual deterioration.

Objective

To determine the efficacy and complications of transcranial optic nerve sheath fenestration (ONSF) using an ultrasonic aspirator as an adjunct in the treatment of refractory IIH.

Material and Methods

This prospective study included all patients with medically refractory IIH with visual deterioration from November 2017 to June 2019. Pterional craniotomy was followed by extradural clinoidectomy and optic foramen bony decompression using an ultrasonic aspirator. All the cases were followed up for changes in visual acuity and field and surgical outcomes.

Results

A total of 21 consecutive patients who underwent ONSF in the study period were included for analysis. Improvement in visual acuity was noted in 19/21 (90.47%) patients. Improvement in visual fields was noted in 17/21 (80.95%). Headache improved in 66.67% of patients. Improvement in the fundus picture was noted in 90.47%. Symptoms < 6 months showed better results compared to > 6 months symptom, although statistically nonsignificant (P = 0.2556). A 270-degree optic canal decompression was achieved in all the cases.

Conclusion

Transcranial optic nerve sheath decompression with a bone ultrasonic aspirator is a safe and direct decompression of the optic nerve in malignant/refractory cases of IIH.

Approach to patient with unilateral optic disc edema and normal visual function

In patients with swollen optic nerve head and normal visual function, optic disc drusen (ODD) is the most common diagnosis. The best tests for detecting ODD are funds autofluorescence and enhanced-depth imaging ocular coherence tomography (EDIOCT). After ODD has been ruled out, asymmetric papilledema should be assumed to be the cause and MRI of the brain and orbits with contrast and venography should be performed in all patients. It allows one to look for indirect signs of increased inctracranial pressure (ICP), optic perineuritis, and other inflammatory or compressive processes affecting optic nerve or its sheath such as optic nerve sheath meningioma. If imaging signs of raised ICP are present, lumbar puncture should be performed with measurement of opening pressure and analysis of cerebrospinal fluid (CSF) contents in all patients with fever, meningismus or neurologic deficits as well as patients who are not in the typical demographic group for idiopathic intracranial hypertension (IIH). Optic nerve sheath enhancement on MRI should prompt work-up for causes of optic perineuritis. When the appropriate neuroimaging is normal, the differential diagnosis is limited and ophthalmological consultation is necessary to determine whether other subtle ocular abnormalities are present on biomicroscopic and dilated fundus examination.

Optic nerve sheath fenestration via a supero-medial eyelid skin crease approach for the treatment of idiopathic intracranial hypertension in a UK population

BACKGROUND/AIMS

Optic nerve sheath fenestration (ONSF) is a surgical intervention in the management of idiopathic intracranial hypertension (IIH) infrequently performed in the United Kingdom. Numerous surgical approaches have been described, including medial transconjunctival, lateral and endoscopic. We describe our outcomes and complications from ONSF via a supero-medial eyelid skin crease incision in patients with IIH.

METHODS

We performed a retrospective review of consecutive patients undergoing ONSF for IIH between January 2011 and December 2017 by a single surgeon.

RESULTS

Thirty patients were included in the analysis with a median follow-up of 14.5 months. Bilateral ONSFs were undertaken in 27 (90%). The data from one eye per patient were analysed. The mean kinetic perimetry score in mean radial degrees of the I4e isopter improved from 27.3° to 35.7°, p = 0.04. After removing cases with optic atrophy, the median modified Frisén grade of papilloedema improved from 2.5 to 1.0, p = 0.007. A total of 5/30 (17%) patients had complications: two (7%) had recurrence/late failure (one managed medically and one with cerebrospinal fluid [CSF] diversion surgery), one had transient cotton wool spots post-operatively, one had transient retinal haemorrhages and one patient had a transiently oval pupil. No patients had repeat ONSF, but CSF diversion surgery was subsequently carried out in 4/30 (13%) patients.

CONCLUSIONS

ONSF via a supero-medial eyelid skin crease approach is effective at improving visual function in patients with IIH. The complication rates are low when compared with CSF diversion surgery and other surgical approaches for ONSF.

A systematic review of surgical treatments of idiopathic intracranial hypertension (IIH)

Idiopathic intracranial hypertension denotes raised intracranial pressure in the absence of an identifiable cause and presents with symptoms relating to elevated ICP, namely headaches and visual deterioration. Treatment of IIH aims at reducing intracranial pressure, relieving headache and salvaging patients' vision. Surgical interventions are recommended for medically refractory IIH and include CSF diversion techniques, optic nerve sheath fenestration, bariatric surgery and venous sinus stenting. Prospective studies on the surgical options for IIH are scant and no evidence-based guidelines for the surgical management of medically refractory IIH have been established. A search in Cochrane Library, MEDLINE and EMBASE from 1 January 1985 to 19 April 2019 for controlled or observational studies on the surgical treatment of IIH (defined in accordance with the modified Dandy or the modified Friedman criteria) in adults yielded 109 admissible studies. VSS improved papilledema, visual fields and headaches in 87.1%, 72.7% and 72.1% of the patients respectively, with a 2.3% severe complication rate and 11.3% failure rate. CSF diversion techniques diminished papilledema, visual field deterioration and headaches in 78.9%, 66.8% and 69.8% of the cases and are associated with a 9.4 severe complication rate and a 43.4% failure rate. ONSF ameliorated papilledema, visual field defects and headaches in 90.5, 65.2% and 49.3% of patients. Severe complication rate was 2.2% and failure rate was 9.4%. This is currently the largest systematic review for the available operative modalities for IIH. VSS provided the best results in headache resolution and visual outcomes, with low failure rates and a very favourable complication profile. In light of this, VSS ought to be regarded as the first-line surgical modality for the treatment of medically refractory IIH.

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.

Efficacy, complications and cost of surgical interventions for idiopathic intracranial hypertension: a systematic review of the literature

BACKGROUND

To define the efficacy, complication profile and cost of surgical options for treating idiopathic intracranial hypertension (IIH) with respect to the following endpoints: vision and headache improvement, normal CSF pressure restoration, papilloedema resolution, relapse rate, operative complications, cost of intervention and quality of life.

METHODS

A systematic review of the surgical treatment of IIH was carried out. Cochrane Library, MEDLINE and EMBASE databases were systematically searched from 1985 to 2014 to identify all relevant manuscripts written in English. Additional studies were identified by searching the references of retrieved papers and relative narrative reviews.

RESULTS

Forty-one (41) studies were included (36 case series and 5 case reports), totalling 728 patients. Three hundred forty-one patients were treated with optic nerve sheath fenestration (ONSF), 128 patients with lumboperitoneal shunting (LPS), 72 patients with ventriculoperitoneal shunting (VPS), 155 patients with venous sinus stenting and 32 patients with bariatric surgery. ONSF showed considerable efficacy in vision improvement, while CSF shunting had a superior headache response. Venous sinus stenting demonstrated satisfactory results in both vision and headache improvement along with the best complication profile and low relapse rate, but longer follow-up periods are needed. The complication rate of bariatric surgery was high when compared to other interventions and visual outcomes have not been reported adequately. ONSF had the lowest cost.

CONCLUSIONS

No surgical modality proved to be clearly superior to any other in IIH management. However, in certain contexts, a given approach appears more justified. Therefore, a treatment algorithm has been formulated, based on the extracted evidence of this review. The traditional treatment paradigm may need to be re-examined with sinus stenting as a first-line treatment modality.

Meta-Analysis of CSF Diversion Procedures and Dural Venous Sinus Stenting in the Setting of Medically Refractory Idiopathic Intracranial Hypertension

BACKGROUND AND PURPOSE

In medically refractory idiopathic intracranial hypertension, optic nerve sheath fenestration or CSF shunting is considered the next line of management. Venous sinus stenosis has been increasingly recognized as a treatable cause of elevated intracranial pressure in a subset of patients. In this article, we present the results of the largest meta-analysis of optic nerve sheath fenestration, CSF shunting, and dural venous sinus stenting. This is the only article that compares these procedures, to our knowledge.

MATERIALS AND METHODS

We performed a PubMed search of all peer-reviewed articles from 1988 to 2014 for patients who underwent a procedure for medically refractory idiopathic intracranial hypertension.

RESULTS

Optic nerve sheath fenestration analysis included 712 patients. Postprocedure, there was improvement of vision in 59%, headache in 44%, and papilledema in 80%; 14.8% of patients required a repeat procedure with major and minor complication rates of 1.5% and 16.4%, respectively. The CSF diversion procedure analysis included 435 patients. Postprocedure, there was improvement of vision in 54%, headache in 80%, and papilledema in 70%; 43% of patients required at least 1 additional surgery. The major and minor complication rates were 7.6% and 32.9%, respectively. The dural venous sinus stenting analysis included 136 patients. After intervention, there was improvement of vision in 78%, headache in 83%, and papilledema in 97% of patients. The major and minor complication rates were 2.9% and 4.4%, respectively. Fourteen additional procedures were performed with a repeat procedure rate of 10.3%. Three patients had contralateral stent placement, while 8 had ipsilateral stent placement within or adjacent to the original stent. Only 3 patients required conversion to CSF diversion or 2.2% of patients with stents.

CONCLUSIONS

Patients with medically refractory idiopathic intracranial hypertension have traditionally undergone a CSF diversion procedure as the first intervention. This paradigm may need to be re-examined, given the high technical and clinical success and low complication rates with dural venous sinus stenting.

Visual Outcomes from Shunting for Idiopathic Intracranial Hypertension

A retrospective notes review was conducted for 50 consecutive patients who underwent shunt surgery for idiopathic intracranial hypertension (IIH). The decimal visual acuity and the mean radial degrees (MRD) of the I4e isopter of the Goldmann visual field were measured pre-operatively and after a mean follow-up period of 1123 days (range: 13-3551 days). A ventriculo-peritoneal shunt was the first procedure in 38 patients and a lumbo-peritoneal shunt in 12. The mean decimal visual acuity of the worse affected eye improved from 0.75 to 0.84, p = 0.011. The MRD score of the worse affected eye improved on average from 25.6° to 35.5°, p < 0.0001. In those with significant pre-operative visual impairment in their worse affected eye (defined as an MRD score ≤30°), the MRD score improved on average from 10.3° to 26.5°, p = 0.0008. The mean number of surgical procedures for each patient was 2.8 (range: 1-15). Taking all surgical procedures into account, post-operative complications were experienced by 30 patients. At last follow-up, 28 patients still complained of headache, 8 of whom had the intervention performed primarily for headache. Shunting can improve visual function in patients with IIH. There is significant post-operative morbidity and often the need for repeated procedures. Headache also commonly remains in these patients. There is a need for a randomised controlled trial of operative interventions in IIH. Sample size calculations for such a trial to treat significant vision loss are presented.