Endoscopic Endonasal Optic Nerve Decompression with Durotomy: Pis Aller in the Mind of a Blind

Endoscopic Endonasal Optic Nerve Decompression in Idiopathic Intracranial Hypertension: When to Implement Optic Nerve Sheath Fenestration

BACKGROUND AND OBJECTIVE

Idiopathic intracranial hypertension (IIH) is a syndrome characterized with increased intracranial pressure and normal cerebrospinal fluid (CSF) composition. Treatment is mainly conservative, whereas CSF diversion surgery is the most frequently used surgical intervention. Endoscopic endonasal optic nerve decompression (EOND) is a newer surgical treatment of this patient group. This study presents a single clinic's case series with comparative results of unilateral an bilateral EOND with or without optic nerve fenestration.

METHODS

Sixteen patients with IIH syndrome who underwent 18 EOND procedures by a single neurosurgeon were evaluated with MRI and digitally subtracted angiography preoperatively. Both preoperative and postoperative visual acuity and perimetry and fundoscopy examinations were routinely performed. All patients underwent sphenoidotomy using the endoscopic binostril approach; however, unilateral or bilateral optic nerve decompression and accompanying optic sheath fenestration was determined on a case-by-case basis, after which all patients were also evaluated for the outcome of headaches.

RESULTS

Most of the patients were female, and the mean age was 30.28 ± 9.78 years. CSF pressure was increased in all patients (406.43 ± 112.91 mm of H 2 O), and the follow-up period was 61.72 ± 21.67 months. In patients with unilateral EOND, visual fields improved in 83%, visual acuity in 70%, headache in 75%, and papilledema in 27% of cases. In patients with bilateral EOND, perimetry improved in 86%, visual acuity in 43%, headache in 50%, and papilledema in 57% of cases.

CONCLUSION

EOND is an effective surgical option in the treatment of IIH. Bilateral decompression is preferable in patients with bilateral visual involvement, and optic nerve fenestration may prove to be helpful in patients with IIH whose primary complaint is headache.

Endoscopic endonasal optic nerve sheath decompression (EONSD) for idiopathic intracranial hypertension: Technical details and meta-analysis

BACKGROUND

The neurosurgical management of idiopathic intracranial hypertension (IIH) remains controversial. Although shunting and newer endovascular stenting techniques are part of the neurosurgical armamentarium to treat medically refractory IIH symptoms, optic nerve sheath fenestration has traditionally been performed by ophthalmologists.

OBJECTIVE

We present a detailed cadaveric dissection that simulates the endoscopic endonasal optic nerve sheath decompression (EONSD) technique along with the literature review.

METHODS

EONSD was performed in four freshly injected cadaveric specimens. Additionally, a systematic review from different electronic databases has been done.

RESULTS

Bilateral EONSD was performed in all specimens without significant technical difficulties. Based on our experience, there is no need to expose the periorbita or orbital apex. The primary anatomic landmarks were the optic canal, the lateral opticocarotid recess, the tuberculum, the limbus, and the clinoid segment of the internal carotid artery. Based on the systematic review, 68 patients (77.9% female) underwent EONSD, with a mean age of 33.4 ± 6.9 years in adult patients. Follow-up ranged from 3 to 58 months across different studies. The pooled meta-analysis showed headache, papilledema, and visual disturbance improvement in 78% [95%CI 0.65-0.90], 72% [95%CI 0.61-0.83], and 88% [95%CI 0.80-0.96] of cases who underwent EONSD, respectively. The subgroup analysis showed there was no statistically significant difference between unilateral and bilateral EONSD in terms of different measured outcomes.

CONCLUSION

EONSD is a feasible surgical procedure that may obviate the need for shunting in patients with IIH. Although clinical studies showed that EONSD is a safe and effective technique, further studies are required to establish the preferences of either unilateral or bilateral approaches.

Endoscopic endonasal optic nerve decompression: treatment of fibrous dysplasia in a pediatric population

OBJECTIVE

Patients with fibrous dysplasia (FD) of the anterior skull base can experience progressive visual loss and impairment. The authors reviewed their experience with endonasal decompression of the optic nerve (ON) in this patient population. Endoscopic ON decompression (EOND) is a feasible surgical approach for children with FD and visual deficit due to structural ON compression.

METHODS

Electronic medical records of children between 1 and 17 years of age with unilateral FD of the anterior skull base and concomitant ON compression, who required EOND between 2017 and 2022 (n = 4), were reviewed for demographic data, both pre- and postoperative imaging, and evaluations by an otolaryngologist, neurosurgeon, and ophthalmologist in a multidisciplinary fashion.

RESULTS

EOND was found to be a safe and effective surgery for children with FD. Visual acuity was stable in 80% of the eyes postoperatively. Visual fields improved in 40% of the eyes and remained stable in the rest.

CONCLUSIONS

EOND is beneficial for progressive optic neuropathy that is unresponsive to steroid therapy and can prevent permanent disability if performed prior to irreversible damage to the nerve. EOND can decompress the edematous ON with proper exposure of the optic canal and orbital apex, without any major complications.

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.

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.

Endoscopic Bilateral Optic Nerve Decompression for Treatment of Idiopathic Intracranial Hypertension

Objective: To evaluate the results of bilateral endoscopic optic nerve decompression (EOND) with the opening nerve sheath (ONS) technique in patients with idiopathic intracranial hypertension (IIH). Methods: Between the years of 2017 and 2019, we retrospectively evaluated nine IIH patients with progressive visual impairment despite medical treatment and who were treated with the EOND and ONS techniques. We also demonstrated our surgical technique recipe on postmortem human heads in a stepwise manner. Results: There were 9 patients (7 females and 2 males) between the ages of 21 and 72 included in this study, and the mean age was 40.8. All patients had an impairment in visual acuity and/or their visual field, with signs of papilledema and/or optic atrophy. The patients were followed up with for 9–48 months. Improvements in visual acuity were observed in 7 out of 9 patients (78%). Visual field defects improved in 5 out of 8 patients (62.5%). Papilledema was resolved in all patients (100%). Headaches improved in all symptomatic patients (100%). No intraoperative or postoperative complications were observed. Conclusions: EOND is a safe and effective surgical procedure in selected patients with IIH. Bilateral wide bony decompression and nerve fenestration can also be an additional benefit for headache relief. Further clinical series and long-term follow-up are needed for more precise results.