Optic neuropathy related to Onodi cell mucocele: a systematic review and meta-analysis of randomized controlled trials

Background Onodi cells (OC) are important for rhinologists because they contain the optic canal, and are close to the optic nerve and internal carotid artery. Therefore, any pathologic processes within OCs, including infectious or inflammatory sinusitis, fungus ball, inverted papilloma, mucocele, or sino-nasal malignancy can cause devastating ophthalmologic complications. We aimed to define the different optic neuropathy conditions related to isolated OC mucoceles, determine the different symptoms of each condition and its risk factors, and explore the efficacy of the relevant diagnostic tools and treatment strategies. Methodology A comprehensive electronic search with time and language restrictions was conducted. Several known databases were included: PubMed, The Cochrane Library, and Web of Science from 1990 to 2020. We combined the search terms and limited the study to the English language. We removed duplicates, and the articles were screened based on title, abstract, and full text according to the PRISMA checklist. Results The electronic search strategy conducted in this review resulted in 409 hits. After removing duplicate studies and studies with inadequate information, 20 case studies were finally included in this analysis, 65% of which presented men (n = 13), and seven presented women (35%). The mean age reported in these studies was 54.75 with a standard deviation of 14.62 years. We found that visual disturbances that can lead to visual loss were present in most cases (75% of cases). Other symptoms included headache (35%) and eye pain (30%). The risk factors for developing optic neuropathy conditions related to OC mucoceles include being Asian and elderly with a history of either nasal or eye conditions. Our findings showed that the mean time between the onset of symptoms and intervention was 16.8 ± 21.8 days. Most patients underwent endoscopic sinus surgery to remove the OC mucocele (18/20; 90%) with a success rate of 77%. Pharmacologic intervention as a solo treatment (IV corticosteroids or /and antibiotic) was used in only six patients, with a success rate of only 33%. Computed tomography (CT) and magnetic resonance imaging (MRI) is the most commonly used diagnostic tools, with diagnostic success rates of 40% and 82.3%, respectively. Conclusion Optic neuropathy conditions related to OC mucoceles are very rare. However, a higher incidence of these conditions was observed in elderly Asian patients with a history of nasal or optic conditions. Visual disturbances are the most common symptoms accompanying any type of eye condition. Endoscopic sinus surgery is considered an effective and safe intervention for these patients, and the period between the onset of symptoms and surgery does not affect the outcomes of the surgery. Furthermore, treatment with corticosteroids and/or antibiotics cannot replace surgery and it can also worsen the condition. Moreover, MRI is superior to CT scans for demonstrating this abnormality, and both are superior to other diagnostic tools. Finally, further investigations should be conducted to study the causes of the low incidence of these conditions in the eastern region.