Imaging Analysis of Onodi Cells on Cone-Beam Computed Tomography

Abstract Introduction Onodi cells are the most posterior ethmoid air cells, and extend superolaterally to the sphenoid sinus. The identification of Onodi cells is essential to because they can have some significant anatomic variations and relationships to vital adjacent structures, like the optic canal, the sphenoid sinus, and the internal carotid artery. Objective The present study aimed to assess the prevalence of Onodi cells and their position with respect to sphenoid sinus. To the authors' best knowledge, this is the first study that uses cone-beam computed tomography (CBCT) to assess the prevalence and position of Onodi cells. Methods We collected CBCT scan records from November 1st, 2016, to July 31st, 2017; the patients who fulfilled the eligibility criteria were included in the present study. The CBCT scans were reviewed by two independent observers. The descriptive statistics was performed using the Statistical Package for the Social Sciences (SPSS, SPSS, Inc., Chicago IL, US) software, version 17.0. A cross-tabulation of gender with the presence and position of Onodi cells was evaluated using the Chi-squared (χ2) test. The inter- and intraobserver agreements were evaluated using Kappa (κ) statistics. Results Onodi cells were identified in 86 (42.8%) out of 201 patients. A subgroup analysis revealed that Onodi cells were present in 45 (43.3%) female and 41 (42.3%) male patients. The position of the Onodi cells was superior with respect to the sphenoid sinus in 43 (50%) of the patients, superolateral in 36 (41.9%), and lateral to the sphenoid sinus in 7 (8.1%) of the patients. Conclusion The present study indicated a high prevalence of Onodi cells, with approximately equal distribution among males and females, and mostly superior in position in relation to the sphenoid sinus.

The role of Onodi cells in sphenoiditis: results of multiplanar reconstruction of computed tomography scanning / Papel das células de Onodi na esfenoidite: resultados da tomografia computadorizada com reconstrução multiplanar

Abstract Introduction Onodi cells are the most posterior ethmoid air cells and extend superolateral to the sphenoid sinus. These cells are also intimately related with the sphenoid sinus, optic nerve, and carotid artery. Radiologic evaluation is mandatory to assess for anatomic variations before any treatment modalities related to the sphenoid sinus. Objective To evaluate the effect of Onodi cells on the frequency of sphenoiditis. Methods A retrospective analysis was performed in 618 adult patients who underwent high-resolution computed tomography between January 2013 and January 2015. The prevalence of Onodi cells and sphenoiditis was evaluated. Whether the presence of Onodi cells leads to an increase in the prevalence of sphenoiditis was investigated. Results Onodi cell positivity was observed in 326 of 618 patients and its prevalence was found to be 52.7%. In the study group, 60.3% (n = 73) were ipsilaterally (n = 21) or bilaterally (n = 52) Onodi-positive, whereas 39.7% (n = 48) were Onodi-negative (n = 35) or only contralaterally Onodi-positive (n = 13). Of the control group, 48.3% (n = 240) were Onodi-positive and 51.7% (n = 257) were Onodi negative. The co-existence of Onodi cells ipsilaterally was observed to increase the identification of sphenoiditis 1.5-fold, and this finding was statistically significant (p < 0.05). Conclusion The prevalence of sphenoiditis appears to be higher in patients with Onodi cells. However, it is not possible to state that Onodi cells are the single factor that causes this disease. Further studies are needed to investigate contributing factors related to sphenoiditis.

Resumo Introdução As células de Onodi são as células etmoidais mais posteriores, que se prolongam superolateralmente ao seio esfenoidal. Essas células também se encontram em íntima relação com o seio esfenoidal, o nervo óptico e a artéria carótida. Para análise de variações anatômicas antes da implantação de qualquer modalidade terapêutica relacionada ao seio esfenoidal, a avaliação radiológica é obrigatória, Objetivo Nosso objetivo foi avaliar o papel das células de Onodi na frequência de esfenoidite. Método Em nosso estudo, foi feita uma análise retrospectiva em 618 pacientes adultos que se submeteram à tomografia computadorizada de alta resolução entre janeiro de 2013 e janeiro de 2015. Avaliamos a prevalência de células de Onodi e de esfenoidite. Investigamos se a presença de células de Onodi leva a um aumento na prevalência de esfenoidite. Resultados A positividade para células de Onodi foi observada em 326 de 618 pacientes e sua prevalência foi de 52,7%. No grupo de estudo, 60,3% (n = 73) eram CO-positivas: ipsilateral (n = 21) ou bilateralmente (n = 52); e 39,7% (n = 48) eram CO-negativas (n = 35) ou apenas contralateralmente CO-positivas (n = 13). No grupo de controle, 48,3% (n = 240) eram CO-positivas; e 51,7% (n = 257) eram CO-negativas. Observamos que a coexistência de CO ipsilateralmente aumentava em 1,5 vez a associação com esfenoidite e esse achado foi estatisticamente significante (p < 0,05). Conclusão A prevalência de esfenoidite parece ser maior em pacientes com células de Onodi, mas não é possível afirmar que elas são isoladamente o fator causador dessa doença. Novos estudos precisam ser feitos para uma investigação dos fatores contributivos relacionados à esfenoidite.

A Case of Optic Neuropathy Caused by Fungal Ball in an Onodi Cell

PURPOSE: To report a rare case of optic neuropathy caused by a fungal ball in an Onodi cell. CASE SUMMARY: A 63-year-old female was referred to our clinic with relapsed visual loss and ocular pain in the right eye. She had been diagnosed as optic neuritis 14 days before and given pulse steroid therapy. She recovered to normal but relapsed 7 days before. In medical referral there was no suspected multiple sclerosis but only a few inflammation in the paranasal sinuses. On our initial examination, best corrected visual acuity was counting finger at 10 cm in the right eye, and 1.0 in the left eye, along with relative afferent pupillary defect in the right eye. The fundoscopic examinations disclosed disc swelling; nearly total visual field defect was observed on visual field examination and visual evoked potential test revealed decreased amplitude at P100 wave in the right eye. Clinical impression was relapsed optic neuritis. After the administration of pulse steroid therapy, her disc swelling was decreased and visual acuity was recovered to 0.6, however, visual acuity was exacerbated to 0.4 in 2 weeks. We checked outside brain magnetic resonance imaging (MRI) and the result showed optic neuropathy caused by a fungal ball in an Onodi cell. The patient was referred to otorhinolaryngologist and fungal ball was removed by endoscopic sinus surgery. 3 weeks after surgery the patient's visual acuity was 0.9, no disc swelling was found and visual evoked potential was recovered to normal. CONCLUSIONS: An Onodi cell lesion should be considered in the differential diagnosis of optic neuritis, identified by imaging studies and promptly removed by surgery for visual recovery.

Acute Visual Loss Caused by Onodi Cell Mucopyocele

Acute visual loss caused by an infected mucocele in an Onodi cell is extremely rare. The Onodi cell is a pneumatized posterior ethmoid cell located laterally and superiorly to the sphenoid sinus and closely related to the optic nerve. Therefore, a mucocele affecting the Onodi cell that has encroached on the adjacent sphenoid bone forming the optic canal can rarely present with visual loss. We describe a rare case of retrobulbar optic neuritis caused by an infected mucocele in the Onodi cell. A 54-year-old male complained of headache and visual loss in his right eye. A computed tomography scan and magnetic resonance image demonstrated a mucocele occupying the Onodi cell on the right side. Surgical treatment with an endoscopic sinus approach was performed, resulting in improvement of visual acuity. A lesion in an Onodi cell may be associated with ocular symptoms even if the lesion is isolated or small. Imaging studies should be considered for the differential diagnosis because early diagnosis and prompt surgical treatment for mucocele are needed for recovery of visual function.

A Case of Fungal Infection in Onodi Cell with Visual Loss / 대한이비인후과학회지

The Onodi cell, which is a posterior ethmoid cell that gets pneumatized far laterally and to some degree superiorly to the sphenoid sinus, is intimately associated with the optic nerve. The problem with most cases of Onodi cells is that acute visual loss may occur in association with a compression to the optic nerve by a mucocele of an Onodi cell. We report, with a review of literature, a case of fungal infection in Onodi cells with acute visual loss in a 71 year-old female patient, who was treated by endoscopic sinus surgery with electrical drill and steroid therapy.

Incidence and Types of Sphenoethmoid Cell in Patients with Chronic Paranasal Sinusitis

The sphenoethmoid cell is the most posterior ethmoid cell, pneumatizing far laterally and to some degree superiorly to the sphenoid sinus. A accurate understanding of the sphenoethmoid cell is important for avoiding fatal injury to the orbit and safely approaching the sphenoid sinus. To investigate the incidence of sphenoethmoid cells, the authors analyzed the coronal CT scans of 50 patients who underwent endoscopic sinus surgery for sinusitis. Sphenoethmoid cells were identified in 39 out of 100 nasal cavities and divided into two types according to their relationship with the optic canal and the sphenoid sinus : type 1 cells, where the optic nerve bordered the sphenoethmoid cell and the sphenoid sinus, were observed in 14 cavities, and type 2 cells, where the optic nerve bordered only the sphenoethmoid cell, were observed in 25 cavities. We anticipate the existence of an optic canal in the posterior ethmoid sinus in one third of the cases, and the direction of the approach to the anterior wall of the sphenoid sinus should be modified according to the type of sphenoethmoid cell if one is present.