Optic nerve sheath fenestration for vision preservation in idiopathic intracranial hypertension

Cranial decompression and expansion surgery for the treatment of refractory idiopathic intracranial hypertension: case report and systematic review

OBJECTIVE

The purpose of this study is to systematically review the literature on the clinical outcomes following different surgical techniques in patients with refractory idiopathic intracranial hypertension (IIH).

BACKGROUND

IIH is a condition characterised by increased cranial pressure (ICP) in the absence of an intracranial lesion that does not adequately respond to different medical and surgical therapies. Cranial decompression or expansion surgeries are a last resort therapy for patients with refractory IIH.

METHODS

A systematic literature search of the databases of PubMed, Embase and Medline from inception to 2019 was performed. Searches were limited to the English language and to clinical studies. Studies were included if clinical outcomes following different cranial decompression or expansion techniques were reported. We also add one case of our own experience with performing a bilateral frontoparietal expansion craniotomy and subtemporal craniectomy.

RESULTS

Five manuscripts, describing 38 procedures, met the inclusion criteria. Thirty-one patients were female (82%). The mean age was 26.2 years. The techniques studied included subtemporal craniectomy (27/38, 71%), internal cranial expansion (10/38, 26%), and cranial morcellation decompression (1/38, 3%). Thirty-five patients presented with headaches of which 17 noted postoperative improvement or resolution (49%). Visual deficits were documented in 30 patients and 25 reported postoperative improvement (83%). Papilledema disappeared in 23 of 32 patients with this sign at presentation (72%). In our patient, symptoms completely resolved postoperatively and a 6% increase in intracranial volume was measured.

CONCLUSIONS

Cranial vault decompression or expansion surgeries may be an effective last resort therapy for patients with refractory IIH. These surgeries expand the intracranial volume, and thus may normalise ICP, leading to clinical improvement.

Role of Optic Nerve Sheath Fenestration in Inflammatory Pachymeningitis Causing Visual Impairment

Eye disease due to pachymeningitis caused by immunoglobulin G4-related disease (IgG4-RD) is a rare occurrence. Here, the authors report a unique case of a patient presenting with visual loss from raised intracerebral pressure from pachymeningitis most likely related to IgG4-RD. The patient was treated with acetazolamide and steroids, and an optic nerve sheath fenestration was performed to successfully save the patients vision.

Superonasal Transconjunctival Optic Nerve Sheath Decompression: A Simplified Technique for Safe and Efficient Decompression

BACKGROUND

Severe, permanent vision loss is a feared sequela of untreated or refractory idiopathic intracranial hypertension (IIH). For patients with progressive vision loss despite maximally tolerated medical treatment, optic nerve sheath decompression (ONSD) remains a viable and effective option to protect vision. Our objective is to introduce a modified transconjunctival technique for ONSD and determine its safety, efficacy, and efficiency in patients with IIH.

METHODS

We performed analyses for a retrospective case series of consecutive patients with IIH by modified dandy criteria who underwent isolated superonasal transconjunctival optic nerve sheath decompression (stOND) at single eye institute in a large academic center from January 2013 to February 2017. Sixty-six patients were identified who met these criteria with at least 6 weeks of follow-up data. Primary outcome measures were visual field mean deviation, grading of papilledema by the modified Frisen scale, and best-corrected visual acuity. Secondary outcome measures were presence of postoperative diplopia and operative time.

RESULTS

One hundred thirty-two eyes of 66 patients were identified; 58 were female (88%), and 8 were male (12%). The mean age was 30 years (range 13-55) with an average lumbar puncture opening pressure of 38 cm H2O. Participants mean body mass index was 36 (range 20-59) with Grade 3 papilledema on average by the modified Frisen scale. No patients experienced operative complications, postoperative diplopia, or worse visual acuity at 1 week after surgery. Average operative time was 50 minutes (range: 25-89). The median decrease in papilledema grading was 3 grades on the Frisen scale (95% confidence interval [CI], 2-3, P < 0.0001). Snellen visual acuity changes did not meet statistical significance. The average Humphrey Visual Field mean deviation change was +1.91 (95% CI, 0.58-3.24, P = 0.0052). Despite successful bilateral decompressions, 4 patients (6.1%) progressed in their visual loss.

CONCLUSIONS

The superonasal transconjunctival approach to ONSD is a safe, efficient and effective surgical treatment for patients with deteriorating visual function due to IIH. Although additional study is required to further clarify the best timing and indications for ONSD among other treatment options for refractory IIH, providers should be aware of the reduced complication rates and efficacy of the stOND technique.

“Benign intracranial hypertension” is a misleading name for a more serious disease: analysis of the visual outcome in cases with idiopathic intracranial hypertension

Objective

Assessment of visual field outcomes following the medical or surgical management of increased intracranial pressure in patients with idiopathic intracranial hypertension.

Patient and methods

Thirty-two patients diagnosed with idiopathic intracranial hypertension who met all the modified Dandy criteria were included in this study. Magnetic resonance brain imaging with contrast and magnetic resonance venography were performed to exclude the presence of secondary causes of intracranial hypertension. Following normal neuroimaging, a lumbar puncture was performed for all patients with papilledema to measure the cerebrospinal fluid opening pressure. The assessment of visual function, including visual acuity, fundus examination (dilated fundus examination to confirm the presence and the grade of papilledema and to exclude the other ocular causes of optic disc swelling), and formal visual field assessment by perimetry when visual acuity was more than 1/60 were performed by the ophthalmologist before and after medical or surgical treatment.

Results

Thirty-two patients were included, the majority of whom were females of childbearing age (29/32; 90.6%). All patients complained of headache. Visual assessment revealed the presence of blurry vision in all patients. Papilledema with different grades was observed in 31/32 (96.9%) patients, while the other patient (3.1%) showed optic atrophy; 30/32 (93.8%) patients had visual acuity ˃ 1/60. The average visual field was − 18 dB ± 9.97 SD in the right eye and − 19.47 dB ± 5.43 SD in the left eye. Twenty-nine patients received medical treatment in the form of acetazolamide, which succeeded in controlling idiopathic intracranial hypertension in 24/29 (82.7%) patients, while a theco-peritoneal shunt was inserted in 8/32 (25%) patients. After management, statistically significant improvements in cerebrospinal fluid opening pressure, presenting manifestation, visual acuity, and field were noticed.

Conclusions

Permanent visual loss is the most feared complication of idiopathic intracranial hypertension; therefore, early diagnosis and multidisciplinary treatment are necessary to improve visual acuity and visual field.

Update on the application of optic nerve sheath fenestration

BACKGROUND

With the ongoing development of surgical procedures and instruments, the safety of optic nerve sheath fenestration (ONSF) has been improved.

OBJECTIVE

Through the past three decades, progress has been made in preventing visual loss from chronic optic nerve swelling in idiopathic intracranial hypertension (IIH), secondary intracranial hypertension and local optic nerve diseases. We now review the updated application of ONSF in those diseases.

METHODS

The application of ONSF in papilledema due to IIH, secondary intracranial hypertension to cerebral venous sinus occlusion, Cryptococcal meningitis, and intracranial mass or tumors is reviewed. Additionally, the potential benefits of ONSF in local optic neuropathy from optic nerve sheath meningioma, optic nerve drusen, traumatic optic neuropathy and optic nerve/sheath biopsy are also described.

RESULTS

Although ONSF has little or no effect on intracranial pressure, it is a safe, relative easy and effective surgical procedure to prevent or reverse visual loss in IIH. When other treatment modalities fail to timely protect vision, ONSF can be useful in protecting visual function or delay visual loss in secondary intracranial hypertension.

CONCLUSION

We recommend that ONSF should be considered as a meaningful alternative or an adjunct therapy to reduce or delay the visual morbidity of these diseases, although the use of ONSF for some of them remains controversial.

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.

Resolution of idiopathic intracranial hypertension after sustained lowering of cerebrospinal fluid pressure

Idiopathic intracranial hypertension (IIH) is a syndrome of headache due to raised intracranial pressure (ICP) where the cerebrospinal fluid (CSF) is normal and there is no alternative pathology on imaging. The aetiology is unknown. This review questions many of the prevailing views regarding aetiology and treatment of IIH. It explores the concept that there is a vicious cycle of fluctuating raised ICP leading to secondary compression of the transverse sinuses and further elevation of ICP. It also raises the question as to whether this vicious cycle could be relieved by prolonged drainage of CSF as seen in Lumbar puncture induced low-pressure headache or alternatively a lumbar drain.

Internal cranial expansion surgery for the treatment of refractory idiopathic intracranial hypertension

OBJECT

Idiopathic intracranial hypertension (IIH) may be refractory to available medical and surgical therapies. Patients with this condition may suffer from intractable headaches, experience visual deterioration, or have other symptoms related to elevated intracranial pressure. Internal cranial expansion (ICE) is a novel surgical procedure that the authors have developed for the treatment of patients with this condition. Here, they describe ICE and present their initial experience in using this surgical procedure for the treatment of patients with refractory IIH.

METHODS

The authors conducted a retrospective review of 10 consecutive patients who underwent ICE for the treatment of IIH during a 5-year period. Preoperative and postoperative clinical parameters including patient symptoms, presence of papilledema, and available ICP or CSF opening pressures were compared. Procedural details and complications were noted. Intracranial volume increases were calculated using available pre- and postoperative CT scans.

RESULTS

Follow-up for the 10 patients in this series ranged from 1 to 39.6 months (mean 15.5 months). Technically successful ICE was performed in all patients within the cohort. Surgical complications included a single postoperative seizure in one patient and a sagittal sinus tear with no clinical sequelae in another patient. At the time of last follow-up, 7 (70%) of 10 patients were either symptomatically improved or asymptomatic. Six (67%) of 9 patients with preoperative headaches had reduction or resolution of this symptom, and all patients (4 of 4) with preoperative papilledema had a reduction in or complete resolution of this sign. Postoperative ICP or CSF opening pressures were normal in all patients (4 of 4) tested. Postoperative intracranial volume expansion ranged between 3.8% and 12%.

CONCLUSIONS

Internal cranial expansion is a safe and effective surgery for the treatment of patients with refractory IIH. This surgery expands the intracranial volume and thus promotes ICP normalization, which may lead to the reduction or complete resolution of the signs and symptoms of IIH. Internal cranial expansion may be used as part of a multidisciplinary management approach in the treatment of refractory IIH.

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.

Treatments for neuro-ophthalmologic conditions

Neuro-ophthalmology covers disorders that fall between the cracks of Neurology and Ophthalmology. Neurologists see patients with neuro-ophthalmic disorders. Recognition of the diagnosis is difficult enough, but treatment can be challenging. This article reviews several common neuro-ophthalmic disorders, outlining their features and treatments, from retinal vascular disorders to eye movements and blepharospasm.

Bariatric surgery for the treatment of idiopathic intracranial hypertension

Object

The purpose of this study was to review the literature on the effectiveness of bariatric surgery for obese patients with idiopathic intracranial hypertension (IIH) with regard to both symptom resolution and resolution of visual deficits.

Methods

The published literature was reviewed using manual and electronic search techniques. Data from each relevant manuscript were gathered, analyzed, and compared. These included demographic data, pre- and postoperative symptoms, pre- and postoperative visual field deficits, bariatric procedure type, absolute weight loss, changes in body mass index, and changes in CSF opening pressure.

Results

Eleven relevant publications (including 6 individual case reports) were found, reporting on a total of 62 patients. The Roux-en-Y gastric bypass was the most common bariatric procedure performed. Fifty-six (92%) of 61 patients with recorded postoperative clinical history had resolution of their presenting IIH symptoms following bariatric surgery. Thirty-four (97%) of 35 patients who had undergone pre- and postoperative funduscopy were found to have resolution of papilledema postoperatively. Eleven (92%) of 12 patients who had undergone pre- and postoperative formal visual field testing had complete or nearly complete resolution of visual field deficits, and the remaining patient had stabilization of previously progressive vision loss. In 13 patients both pre- and postoperative CSF pressures were recorded, with an average postoperative pressure decrease of 254 mm H2O. Changes in weight loss and body mass index varied depending on the reported postoperative follow-up interval.

Conclusions

The published Class IV evidence suggests that bariatric surgery may be an effective treatment for IIH in obese patients, both in terms of symptom resolution and visual outcome. Prospective, controlled studies are necessary for better elucidation of its role.

Headache attributed to non-vascular intracranial disorder

This chapter deals with non-vascular intracranial disorders resulting in headache. Headache attributed to high or low cerebrospinal fluid pressure is separated into headache attributed to idiopathic intracranial hypertension (IIH), headache attributed to intracranial hypertension secondary to metabolic, toxic, or hormonal causes, headache attributed to intracranial hypertension secondary to hydrocephalus, post-dural puncture headache, cerebrospinal fluid (CSF) fistula headache, headache attributed to spontaneous (or idiopathic) low CSF pressure. Headache attributed to non-infectious inflammatory disease can be caused by neurosarcoidosis, aseptic (non-infectious) meningitis or lymphocytic hypophysitis. Headache attributed to intracranial neoplasm can be caused by increased intracranial pressure or hydrocephalus caused by neoplasm or attributed directly to neoplasm or carcinomatous meningitis. Other causes of headache include hypothalamic or pituitary hyper- or hyposecretion and intrathecal injection. Headache attributed to epileptic seizure is separated into hemicrania epileptica and post-seizure headache. Finally headache attributed to Chiari malformation type I (CM1) and the syndrome of transient headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL) are described.

[Indications and technique of optic nerve sheath fenestration]

An optic nerve sheath fenestration is indicated when papilloedema leads to progressive visual loss despite previous, conservative measures and when no cause of increased intracranial pressure can be indentified and eliminated. This rather rare constellation usually occurs in idiopathic intracranial hypertension. The procedure is performed via a medial transconjunctival orbitotomy. If headaches and neurologic symptoms other than visual deterioration prevail, the placement of a ventricular shunt is preferred. This review covers the symptoms of idiopathic intracranial hypertension and optic nerve sheath fenestration with its technical aspects and results.

Advances in evaluation and management of pediatric idiopathic intracranial hypertension

PURPOSE OF REVIEW

Although the demographics of pediatric idiopathic intracranial hypertension have been well described, the best approaches to its management are less well defined. Recent advances in evaluation of optic nerve status make it easier to determine when and if more aggressive intervention is required. Medical and surgical approaches are discussed.

RECENT FINDINGS

Modern neuroimaging techniques are used to look for secondary causes of intracranial hypertension such as cerebral venous sinus thrombosis. Automated perimetry is now quicker to perform and is accepted as the gold standard in evaluating optic nerve defects, even in the pediatric population. Other newer techniques for assessing optic nerve injury include optical coherence tomography, laser scanning tomography, and spectral Doppler blood flow analysis of the optic nerve head. Medical management remains the first-line treatment, but increasingly, surgical interventions such as optic nerve sheath fenestration and cerebrospinal fluid shunting are used in the pediatric population.

SUMMARY

Pediatric intracranial hypertension patients may be followed with a greater degree of precision than in the past. Management tends to be similar to that used in adults, now including surgical intervention when indicated. The newer technologies allow us to gather data that may help to determine the optimal time for surgical intervention for those patients who require it.