Findings of magnetic resonance imaging after optic nerve sheath decompression in patients with idiopathic intracranial hypertension

Optic nerve sheath fenestration: A second lease at sight

Purpose

To study the safety and efficacy of optic nerve sheath fenestration surgery in patients with optic disc edema due to different etiologies.

Methods

Records of 18 eyes of 15 patients who underwent optic nerve sheath fenestration for vision threatening optic disc edema were reviewed retrospectively, and results were analyzed. Improvement of visual acuity was the main measure of outcome. Improved visual fields, resolution of optic disc edema, diplopia, and headache were other benefits that were observed.

Results

Fifteen patients between 13 and 54 years of age were included in the study. Three patients underwent successive bilateral surgery. Idiopathic intracranial hypertension was the most common cause for optic disc edema and was found in 80% of the patients. Mean preoperative logMAR acuity was -1.9789 ± 1.46270, which improved to -0.9022 ± 1.23181 (p < 0.005) in the operated eye, and mean logMAR acuity of contralateral eye improved from -1.3378 ± 1.50107 to -1.0667 ± 1.33813 (p < 0.05).

Conclusion

Early optic nerve sheath fenestration is an effective modality for treating optic disc edema due to a wide myriad of causes and helps resolve the associated symptoms.

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.

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.

Advances in magnetic resonance imaging of orbital disease

Magnetic resonance imaging (MRI) is increasingly used by the orbital surgeon to aid in the diagnosis, surgical planning, and monitoring of orbital disease. MRI provides superior soft tissue detail compared with computed tomography or ultrasound, and advancing techniques enhance its ability to highlight abnormal orbital pathology. Diffusion-weighted imaging is a specialized technique that uses water molecule diffusion patterns in tissue to generate contrast signals and can help distinguish malignant from benign lesions. Steady-state free precession sequences such as Constructive Interference in Steady-State (CISS) and Fast Imaging Employing Steady-state Acquisition (FIESTA) generate highly detailed, 3-dimensional reconstructed images and are particularly useful in distinguishing structures adjacent to cerebral spinal fluid. Magnetic resonance angiography can be used to characterize vascular lesions within the orbit. New developments in magnetic field strength as well as the use of orbital surface coils achieve increasingly improved imaging resolution.

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.

Pseudotumor cerebri-Case report

An 46-year-old Caucasian woman was diagnosed with idiopathic intracranial hypertension (IIH) after presenting with papilledema and bilateral visual blurring. Lumbar puncture revealed an opening pressure of more than 550 mmH2O. Cerebral magnetic resonance imaging (MRI) showed bilateral flattening of the posterior sclera, enhancement of the prelaminar optic nerve, distension of the perioptic subarachnoid space, intraocular protrusion of the prelaminar optic nerve and empty sella. The main purpose of the treatment was to release the symptoms and preserve the vision. It was initiated the general treatment with Mannitol 20%, 250 ml/day, Acetazolamide 2x500 mg/day and B-vitamins. After discharge the patient followed a treatment with acetazolamide 2x250 mg/ daily doses and oral potassium supplements 30 mg bid/day. Key words: pseudotumor cerebri, idiopatic intracranial hypertension, papilledema,

Clinical and Magnetic Resonance Imaging Characteristics of Postfenestration Optic Nerve Sheath Pseudomeningoceles

PURPOSE

The clinical significance of postoperative pseudomeningocele formation following optic nerve sheath fenestration (ONSF) has not been fully characterized. A literature review identifies 9 previously published cases the authors believe demonstrate pseudomeningocele formation and approximately 19 other similar findings that were either transient or less defined blebs. This study was undertaken to more clearly define the clinical, radiographic, and histopathologic features associated with this entity.

METHODS

Sixteen-year, single-center, retrospective chart review of all ONSF cases performed by 2 surgeons. Clinical data, intracranial pressure, radiographic imaging, and histopathology of clinically detected pseudomeningoceles after ONSF were reviewed.

RESULTS

Eighty-six eyes in 57 patients underwent ONSF (28 unilateral, 12 bilateral sequential, 17 bilateral simultaneous). Forty-nine of 57 patients had elevated intracranial pressure preoperatively (41 idiopathic intracranial hypertension, 4 venous thrombosis, 2 meningitis, 1 arteriovenous malformation, and 1 sarcoid). In 32 patients undergoing postoperative imaging, 4 eyes (4.7%) in 4 patients developed well-defined pseudomeningoceles, of which 3 were symptomatic and 2 required surgical revision. Each pseudomeningocele developed in the setting of elevated preoperative intracranial pressure (350, 360, 430, 500 mm H20). Magnetic resonance imaging and/or computed tomography revealed sharply demarcated fluid-filled sacs adjacent to the optic nerve. The contents of these sacs were hypointense on T1-weighted imaging, hyperintense on T2-weighting, variably enhanced with contrast, and hypointense on fluid attenuated inversion recovery, and were thus consistent with cerebrospinal fluid. Histopathologic analysis of one of these outpouchings demonstrated an acellular, fibrocollagenized lining consistent with pseudomeningocele. Three eyes in 3 additional patients had less well-defined findings on imaging interpreted as bleb-like or cyst-like change.

CONCLUSIONS

Pseudomeningoceles following ONSF may be asymptomatic or may cause symptomatic orbital mass effect and rarely visual loss, amendable to surgical excision. Post-ONSF pseudomeningoceles are identified on computed tomography or magnetic resonance imaging to occur at the locations of fenestration sites and contain cerebrospinal fluid communicating with the subdural space that may act as a "filtration" bleb in some cases. Imaging findings may represent a spectrum spanning intraorbital cerebrospinal fluid leakage, partial walling off of bleb, or fully developed cysts. Resection of optic nerve pseudomeningoceles is considered in symptomatic cysts or eyes with papilledema that fails to improve.

Update on Idiopathic Intracranial Hypertension

PURPOSE OF REVIEW

This review presents a critical appraisal of current therapeutic strategies for patients with idiopathic intracranial hypertension (IIH). We present the reader with the most recent evidence to support medical and surgical interventions in patients with IIH and provide recommendations about treatment initiation and escalation. We also indicate areas where knowledge gaps exist regarding therapeutic efficacy and superiority of one intervention over another.

RECENT FINDINGS

A double-masked, randomized prospective study of medical management of patients with mild IIH (Idiopathic Intracranial Hypertension Treatment Trial-IIHTT) has established that acetazolamide therapy has additional efficacy when compared to weight loss alone. Furthermore, management of IIH-related headache, even in patients with papilledema, may require treatment other than ICP lowering for patients to experience symptomatic relief. Finally, a number of uncontrolled interventional studies have shown transverse sinus stenting to be a potentially effective treatment for medically refractory IIH. Medical therapy with acetazolamide should be considered in addition to structured weight loss in patients with mild IIH. Surgical treatment for patients with vision-threatening disease IIH can be performed by either optic nerve sheath fenestration or cerebrospinal fluid diversion, with venous sinus stenting emerging as an alternate therapy. Headache relief from ICP lowering therapy is variable and often not sustained.

Efficacy and safety of optic nerve sheath fenestration in patients with raised intracranial pressure

Objective:

To evaluate the efficacy and safety of Optic Nerve Sheath Fenestration (ONSF) in patients with raised intracranial pressure (ICP).

Methods:

This Quasi Experimental Study was conducted at Armed Forces Institute of Ophthalmology, Rawalpindi from July 2013 to July 2015. Thirty one eyes of 18 patients who underwent ONSF for raised ICP were followed up for one year to ascertain efficacy and safety of ONSF procedure.

Results:

Thirteen (72.22%) patients underwent ONSF bilaterally, while five (27.78%) underwent unilateral ONSF. Best corrected visual acuity (BCVA) improved in 24 (77.4%), remained stable in four (12.9%) and deteriorated in three (9.7%) patients. Papilledema improved in 27 (87.1%) while remained stable in four (12.9%) according to Frisénscale of Papilledema. Change in BCVA and papilledema from pre-operative values was statistically significant (p<0.001). There was significant negative correlation (r= -0.434, p=.017) between duration of symptoms before presentation and improvement in BCVA. Common complications were a tonic pupil, subconjunctival haemorrhage, chemosis, weakness of recti and diplopia.

Conclusion:

ONSF is an effective procedure with statistically significant improvement in BCVA and reduction in severity of papilledema.

Outcomes of endoscopic optic nerve decompression in patients with idiopathic intracranial hypertension

BACKGROUND

The conventional treatment for idiopathic intracranial hypertension involves weight loss, steroids, diuretics, and/or serial lumbar punctures; however, if the symptoms persist or worsen, surgical intervention is recommended. Surgical options include cerebrospinal fluid diversion procedures, such as ventriculoperitoneal and lumboperitoneal shunts, and optic nerve decompression with nerve sheath fenestration. The latter can be carried out using an endoscopic approach, but the outcomes of this technique have not been firmly established.

METHODS

This systematic review examined the outcomes of performing endoscopic optic nerve decompression (EOND) in patients with idiopathic intracranial hypertension (IIH). Six studies were included for a total of 34 patients.

RESULTS

The patients presented with visual field disturbances (32 of 32 [100%]), visual acuity disruptions (33 of 34 [97.1%]), papilledema (26 of 34 [76.5%]), and persistent headache (30 of 33 [90.1%]). The mean duration of symptoms ranged from 7 to 32 months. Overall, the patients showed post-EOND improvement in signs and symptoms associated with IIH, specifically visual field deficits (93.8%), visual acuity (85.3%), papilledema (81.4%), and headaches (81.8%). Interestingly, 11 cases showed postoperative improvement in their symptoms with bony decompression of the optic canal alone, without nerve sheath fenestration. There were no major adverse events or complications reported with this approach.

CONCLUSION

EOND appears to be a promising and safe surgical alternative for patients with IIH who fail to respond to medical treatment. Further studies are needed before we can attest to the clinical validity of this procedure.

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).

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.

Idiopathic intracranial hypertension (pseudotumor cerebri): recognition, treatment, and ongoing management

OPINION STATEMENT

Idiopathic intracranial hypertension (IIH, pseudotumor cerebri) is a syndrome of elevated intracranial pressure of unknown cause that occurs predominantly in obese women of childbearing age. It is a diagnosis of exclusion and, therefore, other causes of increased intracranial pressure must be sought with history, imaging, and cerebrospinal fluid examination before the diagnosis can be made. IIH produces symptoms and signs of increased intracranial pressure, including papilledema. If untreated, papilledema can cause progressive irreversible visual loss and optic atrophy. The treatment approach depends on the severity and time course of symptoms and visual loss, as determined by formal visual field testing. The main goals of treatment are alleviation of symptoms, including headache, and preservation of vision. All overweight IIH patients should be encouraged to enter a weight-management program with a goal of 5-10 % weight loss, along with a low-salt diet. When there is mild visual loss, medical treatment with acetazolamide should be initiated. Other medical treatments can be added or substituted when acetazolamide is insufficient as monotherapy or poorly tolerated. When visual loss is more severe or rapidly progressive, surgical interventions, such as optic nerve sheath fenestration or cerebrospinal fluid shunting, may be required to prevent further irreversible visual loss. The choice of intervention depends on the relative severity of symptoms and visual loss, as well as local expertise. At present, the role of transverse venous sinus stenting remains unclear. Although there are no evidence-based data to guide therapy, there is an ongoing randomized double-blind placebo-controlled treatment trial, investigating diet and acetazolamide therapy for IIH.

Pseudotumor cerebri: brief review of clinical syndrome and imaging findings

PTC is a clinical entity of uncertain etiology characterized by intracranial hypertension. The syndrome classically manifests with headaches and visual changes in women with obesity. Traditionally, imaging ruled out secondary causes of elevated CSF pressure but now may reveal findings frequently seen in patients with PTC, including the following: flattening of the globe, an empty sella, an enlarged ONS, protrusion and enhancement of the optic nerve head, and increased tortuosity of the optic nerve. Novel imaging methods, including MR venography, have additionally identified sinovenous stenosis as a potential indicator of PTC.

Effect of optic nerve sheath fenestration on papilledema of the operated and the contralateral nonoperated eyes in idiopathic intracranial hypertension

PURPOSE

To evaluate the effect of optic nerve sheath fenestration (ONSF) on papilledema grade in the operated eyes and the contralateral nonoperated fellow eyes in patients with idiopathic intracranial hypertension (IIH).

DESIGN

Retrospective review.

PARTICIPANTS

A total of 78 patients underwent ONSF, and 20 patients served as controls.

METHODS

Charts of patients with IIH who had ONSF at the University of Iowa Hospital and Clinics were reviewed for age, gender, body mass index, and clinical findings. Optic disc photographs were graded by a masked observer using the Frisén papilledema grading scale at preoperative baseline and postoperatively at 2 weeks, 3 months, 6 months, and 12 months follow-up. Wilcoxon signed-rank test was used to examine the change in papilledema grade in both operated and nonoperated eyes at each time point.

MAIN OUTCOME MEASURES

Grade of papilledema.

RESULTS

Sixty-two patients (52 women and 10 men) with a mean age of 32 years (range, 13-57 years) underwent unilateral ONSF. The median grade of papilledema for operated and nonoperated eyes was 3 and 2, respectively, at preoperative baseline. Postoperatively the grade was 2 in each eye at 2 weeks (P<0.0001 and <0.0002 for operated and nonoperated eyes, respectively), 1 in each eye at 3 months (P<0.0001 for both operated and nonoperated eyes), 1 in each eye at 6 months (P<0.0001 for both operated and nonoperated eyes), and 0.5 and 1 for operated and nonoperated eyes, respectively, at 12 months follow-up (P<0.0001 for both operated and nonoperated eyes). There was no significant difference in grade of disc edema or reduction of disc edema on the basis of age, gender, or body mass index.

CONCLUSIONS

Unilateral ONSF significantly decreases the grade of papilledema in both ipsilateral (operated) and contralateral (unoperated) eyes. The reduction of the papilledema and the stability of visual field in the contralateral (nonoperated) eyes suggest that bilateral ONSF may not always be necessary in patients with bilateral visual loss and papilledema due to IIH.

Localized Cystic Enlargement of the Distal Optic Nerve Sheath after Decompression Surgery

Cystic formation of the optic meninges may occur after optic nerve sheath decompression surgery for the management of pseudotumor cerebri. A case with a cyst-like structure of the distal optic nerve sheath at the operation site in the late surgical period after nerve sheath decompression surgery is reported.

Progressive optic neuropathy in idiopathic intracranial hypertension after optic nerve sheath fenestration

A 16-year-old woman complaining of headache and declining vision in both eyes had papilledema, normal brain imaging, and a lumbar puncture showing a moderately high opening pressure (35 cm H2O) and normal cerebrospinal fluid constituents. For a diagnosis of idiopathic intracranial hypertension (IIH), she was treated with acetazolamide and methylprednisolone, but vision worsened, so she underwent bilateral optic sheath fenestration (ONSF). Within the 1st postoperative week, vision had improved and papilledema was less prominent. However, by the 14th postoperative day, vision had worsened and headache persisted. Lumbar puncture showed a very high opening pressure (65 cm H2O), so she underwent ventriculoperitoneal shunting. Although there was a slight initial improvement in vision, it eventually declined further. This case emphasizes that ONSF may yield initial improvement in vision and reduction in papilledema yet not prevent eventual visual loss in IIH. Whether the visual loss in this patient resulted from persistently elevated intracranial pressure after ONSF or was prefigured before ONSF occurred is unresolved. It is a reminder that patients with IIH must be monitored carefully after ONSF. If there is a suggestion of further visual loss, shunting should be considered if intracranial pressure is high.

Clinical review: the surgical treatment of idiopathic pseudotumour cerebri (idiopathic intracranial hypertension)

To review the literature on the surgical treatment of idiopathic pseudotumour cerebri (PTC) [idiopathic intracranial hypertension (IIH)]. When medical therapy fails or when visual dysfunction deteriorates, surgical therapies for PTC should be considered. The main procedures performed include lumboperitoneal shunt (LPS), ventriculoperitoneal shunt (VPS) and optic nerve sheath fenestration (ONSF). Recently, venous sinus stenting procedures have been performed on selected patients with PTC, especially those with venous sinus occlusive disease. The literature is summarized and appraised in the form of a narrative review. It is evident that ONSF, LPS, VPS and, in selected cases, venous sinus stenting may improve vision and prevent deterioration of vision in patients with PTC. All of the procedures have their advantages and disadvantages and may fail with time no matter what procedure is used. Various authorities have vehemently advocated one or the other of these procedures. Until a prospective, randomized study comparing ONSF with LPS or VPS for PTC is performed, and until the role of venous sinus obstruction as the aetiology of PTC is better defined, the question of which surgical procedure is best for the treatment of PTC remains unanswered.