The Whole Lateral Type of the Sphenoethmoidal Cell and Its Relevance to Endoscopic Sinus Surgery.

BACKGROUND: The sphenoethmoidal cell and the sphenoid sinus (SS) show great similarity in endoscopy and imaging. Hence, it is important to accurately identify the sphenoethmoidal cell preoperatively to prevent injury of the nerve and artery during endoscopic surgery. The aim of the present study was to investigate a special type of sphenoethmoidal cell. METHODS: A total of 365 inpatients whose paranasal sinus computed tomography (CT) was collected and reviewed from May 2018 to September 2019 were included. The anatomical imaging characteristics of the sphenoethmoidal cell were observed. RESULTS: A special type of the sphenoethmoidal cell was found on 9 sides in 730 sides (1.3%), according to its extension to the SS. Unlike Onodi cell (49.6%) and Jinfeng cell (1.3%), this cell simultaneously extends toward the superolateral, lateral, and inferolateral regions of the SS and is simultaneously closely attached to the optic canal and the maxillary nerve. Presently, this cell is named as the whole lateral type of the sphenoethmoidal cell, and the SS is located at the medial or inferomedial of it. CONCLUSIONS: When evaluating the paranasal sinus CT preoperatively, attention must be paid to the possibility of the whole lateral type of sphenoethmoidal cell appearing, not just Onodi cell, extending into the SS.

High-resolution computed tomography analysis of the prevalence of Onodi cells.

OBJECTIVES/HYPOTHESIS: Onodi cells are the posterior-most ethmoid air cells that lie superior to the sphenoid sinus. Identification of these cells is essential prior to endoscopic sinus and skull base surgery due to their intricate relationship with the optic nerves and carotid arteries, which may lead to deleterious complications. In this study, high-resolution computed tomography (HRCT) scans from 170 adult-patients were analyzed by two independent observers for the presence of Onodi cells. STUDY DESIGN: Radiographic analysis at a tertiary care medical center. METHODS: A retrospective analysis was performed on patients undergoing HRCT between July 2008 and September 2010. Incidence of Onodi cells and demographic data were collected. RESULTS: The overall prevalence of Onodi cells in this cohort was 65.3%. Subgroup analysis based on ethnicity showed a rate of Onodi cells of 83.3% in Asians, 73.1% in whites, 57.0% in African Americans, and 62.7% in Hispanics. The prevalence of Onodi cells was not significantly different among the different ethnicities (P > .05). However, this was limited by a small sample size in some ethnic groups. Onodi cell prevalence was equivalent among males and females: 62.2% and 63.5% respectively (P > .05). Overall, our results show a greater prevalence of Onodi cells than previously reported. CONCLUSIONS: We found a higher prevalence of Onodi cells in our cohort than previously reported in the literature. Therefore, it is important for surgeons to anticipate the presence of these cells during endoscopic sinus and skull base procedures to prevent potential complications.

The Onodi cell: an obstacle to sellar lesions with a transsphenoidal approach.

OBJECTIVE: The Onodi cell is the posterior-most ethmoid air cell and an important anatomical variant because of the intimate spatial relationship with the optic nerve, internal carotid artery, and sellar floor during sphenoid sinus surgery. The authors evaluated the incidence of Onodi cells, their clinical importance, and the association between preoperative radiological findings and surgical findings. STUDY DESIGN: Case series with chart review. SETTING: Tertiary care medical center. METHODS: The authors retrospectively reviewed the medical records of 162 cases, including preoperative paranasal sinus computed tomography (PNS CT) findings and the findings with the endoscopic endonasal transsphenoidal approach (EETSA). They evaluated the prevalence of Onodi cells and the clinical manifestations in the patients with these cells. They also examined the clinical significance of these cells during EETSA. RESULTS: Onodi cells were identified in the preoperative PNS CT of 53 patients, whereas Onodi cells were observed in 54 (33.3%) of the 162 patients at EETSA. The Onodi cells were bilateral in 23 patients and unilateral in 31. In all cases, the Onodi cells limited the exposure of the sellar floor. Only after removing these cells was the entire sellar floor exposed so that the tumors could be removed completely. CONCLUSION: Onodi cells were observed more frequently than in previous studies, and 98.1% of them were identified on preoperative PNS CT. When reviewing PNS CT images preoperatively, one needs to identify the presence of Onodi cells. The Onodi cells must be removed to completely resect tumors located in the sellar region during EETSA.

Blood-brain barrier opened by stimulation of the parasympathetic sphenopalatine ganglion: a new method for macromolecule delivery to the brain.

OBJECT: Drug delivery across the blood-brain barrier remains a significant challenge. Based on earlier findings, the authors hypothesized that parasympathetic innervation of the brain vasculature could be used to augment drug delivery to the brain. METHODS: Using a craniotomy-cerebrospinal fluid superfusate paradigm in rats with an intravenous injection of tracer the authors demonstrated that stimulation of the postganglionic parasympathetic fibers of the sphenopalatine ganglion (SPG) increased the concentration of fluorescein isothiocyanate-dextran (4-250 kD) in the superfusate by two- to sixfold. A histological examination indicated the presence of dextran in the parenchyma. In another experiment the amount of Evans blue dye in the brain following SPG activation was similarly significantly elevated. The chemotherapeutic agents anti-HER2 monoclonal antibody and etoposide were also delivered to the brain and reached therapeutic concentrations. Brain homeostasis was not disturbed by this procedure; a measurement of nicotinamide adenine dinucleotide reduction did not show a decrease in the tissue metabolic state and brain water content did not increase significantly. CONCLUSIONS: Sphenopalatine ganglion activation demonstrates a promising potential for clinical use in the delivery of small and large molecules to the brain.

Isolated mucocele in an Onodi cell.

A rare case of retrobulbar optic neuropathy caused by an isolated mucocele in an Onodi cell is presented. A 63-year-old man suffering from left recurrent optic neuropathy had shown improved visual acuity with steroid treatment at the age of 48 and 56 years. Impaired visual acuity and blurred vision in the left eye appeared again, and a marked inferior decrease in the left visual field was noted. Although axial computed tomography (CT) showed no abnormal findings, magnetic resonance imaging (MRI) revealed a small squamous-shaped lesion (17 x 17 x 7.3 mm) in the left posterior ethmoidal air cell (Onodi cell) hanging over the left optic nerve. Endoscopic sinus surgery was performed. The optic canal was extruding into the Onodi cell cavity, and the superior bony wall of the canal was eroded by the mucocele. The isolated mucocele in the Onodi cell seemed to be compressing the optic nerve downward an causing retrobulbar optic neuropathy. An Onodi cell lesion, even if it was isolated and small, would cause optic neuropathy. MRI and coronal CT scanning should be performed for the diagnosis and preoperative planning in a case of retrobulbar optic neuropathy.

Epithelial cells in symptomatic Rathke's cleft cysts. A light- and electron-microscopic study.

Epithelial cells composing symptomatic Rathke's cleft cysts were examined electron microscopically in two cases, and the fine structures were compared with those of the mucosa in the normal sphenoid sinus, of the normal choroid plexuses, and of a craniopharyngioma with goblet and ciliated cells. The Rathke's cleft cysts were composed of a single or pseudostratified epithelial layer abutting on the connective tissue. The epithelial cells were of four different kinds of cells, such as goblet, ciliated, flat, and basal cells. The flat cells containing bundles of tonofilaments and desmosomes were the squamous cells. They were present in a single-epithelial layer in both cases. The basal cells were present as small, wedge-shaped cells, even if the number was very small. The epithelial cells in Rathke's cleft cysts were more similar to those of the mucosa in the sphenoid sinus and those of a craniopharyngioma with goblet and ciliated cells than those of the choroid plexus. This study indicates the close relationship between Rathke's cleft cysts and mucosa in the sphenoid sinus or craniopharyngioma with ciliated and goblet cells.

Quantitative histology of the normal sphenoidal sinus.

From 32 normal sphenoidal sinuses in 16 patients the mucosa was removal at autopsy, stained by the PAS-alcian blue whole mount method, and the density of goblet cells as well as of mucous glands was determined. The median density of goblet cells was 6200 cells per mm2, without statistically significant differences between the walls. The median density of glands was very low, 0.06 gland/mm2, highest in the anterior wall which has 0.1 gland/mm2 and lowest in the posterior wall which has 0.05 gland/mm2. The total gland count was less than 50 in 94% of the sinuses, 51--80 in 4%. The glands were small, tubulo-acinous. Hence, the production of mucus by the glands is entirely negligible in relation to that of the goblet cells.