Radiological Observation of Ethmoid Roof on Basis of Keros Classification and Its Application in Endonasal Surgery

Gupta, Pratibha; Ramesh, P.

doi:10.16965/ijar.2017.284

Cited by 9 publications

(6 citation statements)

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“…About the distribution of Keros types, type 2 was the most frequently viewed in this survey, which was similar to the majority of previous reports [ 1 , 3 , 4 , 7 , 8 , 10 , 11 , 13 , 14 , 16 – 19 , 22 – 24 , 26 – 28 , 30 – 32 ]. The most similar one to this study is the costa et al's study, which was done on Brazilian population using CBCT.…”

Section: Discussionsupporting

confidence: 90%

CBCT Assessment of Ethmoid Roof Variations through Keros, Gera, and TMS Classifications

Mahdian

Kheir

2022

International Journal of Otolaryngology

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Background. This study is designed to assess the variations of the ethmoid roof through the Keros, Gera, and Thailand-Malaysia-Singapore (TMS) classifications by means of Cone-Beam Computed Tomography (CBCT). Materials and Methods. 372 CBCT scans were reviewed. The depth of the olfactory fossa (OF) was defined by the height of the lateral lamella (LL). The degree of the angle formed by the LL and the continuation of the horizontal plane passing through the cribriform plate was calculated. The risk of injury to the skull base was assessed by TMS classification. Results. The distribution of Keros types 1, 2, and 3 was 20.43%, 66.26%, and 13.31%, respectively. No significant difference was seen in the Keros classification among males and females, and asymmetry in the depth of the cribriform plate was seen in 33.3% of patients. 29.57% of the cases had type I, 61.42% had type II, and 9.01% had type III of Gera classification. 33.9% of the patients had asymmetry in the Gera classification. There was not significant difference in the Gera classification among males and females. 95.43%, 4.17%, and 0.40% of patients were of types 1, 2, and 3 of TMS classification, respectively. Conclusion. The most prevalent variations of the ethmoid roof were Keros type II, Gera type II, and TMS type 1. Although the prevalence of the dangerous types (Keros type 3, Gera type III, and TMS type 3) was low, preoperative assessment is essential in reducing surgical complications. CBCT is beneficial in evaluating these variations due to its low radiation dose.

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Section: Discussionsupporting

confidence: 90%

CBCT Assessment of Ethmoid Roof Variations through Keros, Gera, and TMS Classifications

Mahdian

Kheir

2022

International Journal of Otolaryngology

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“…Regarding the depth of olfactory fossa, the most frequent type in this study was Keros Type II in agreement with Keros 22 and Yadav et al 38 According to Keros classification, the depth of the olfactory fossa is 1-3 mm in Type I, 4-7 mm in Type II, and 8-16 mm in Type III based on the height of the lateral lamella, the greater the height of the lateral lamella, the higher the risk of its penetration into the anterior cranial fossa. 22 Asymmetry in the anterior of the skull base and especially in the ethmoid roof is important for ESS. Intracranial complications appear more frequently on the side in which the ethmoid roof is low.…”

Section: Discussionsupporting

confidence: 84%

“…The depth of olfactory fossa was classified according to the grading system proposed by Keros into three types. 22 The asymmetry of ethmoidal roof and incidence of aerated crista galli was also investigated. The summation of the unilateral and bilateral abnormalities has been reported as the prevalence of variants without considering the "half-head" as a separate entity.…”

Section: Methodsmentioning

confidence: 99%

Normal anatomic variants of paranasal sinus region studied by computed tomography

Dawood

2020

Zanco J. Med. Sci.

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Background and objective: Variation in paranasal sinus anatomy, as shown on computed tomographic scans, is of potential significance as it may pose risks during surgery or predispose to certain pathologic conditions. This study aimed to investigate the frequency of anatomic variants of the nasal cavity and paranasal sinuses in our population and determine their relationship with gender and find out the association of these variants with mucosal abnormalities. Methods: This was a cross-sectional study conducted at the College of Medicine, Hawler Medical University from October 2017 to January 2019. A review of computed tomography scans of the paranasal sinuses of 300 patients was done; special attention was directed toward identifying bony anatomic variants and mucosal abnormalities. Results: Frequent variants were: Agger nasi cells (72%), nasal septal deviation (71.7%), Haller cells (70.7%), concha bullosa (61%), elongation of uncinate process (69.7%) and different variants of the sphenoidal sinus (78.8%). The frequency of variants did not differ significantly with respect to gender, except for sphenoidal variants along with Keros types and asymmetry of the ethmoidal roof. A significant association was found between middle concha variants and inferior turbinate enlargement (P <0.001). Conclusion: Anatomic variants of the paranasal sinus region were common in our population; the most frequent ones were those involving the nasal septum, ethmoid air cells, sphenoid sinuses, and middle turbinates. The study of these variants is important for the management of paranasal sinus region disease.

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“…There is paucity of in-depth studies regarding OF analysis in the Indian scenario, barring a few which are mentioned below. Previously, Salroo et al [13] (200 subjects), Pawar et al [14] (200 subjects), Satish Nair[15] (180 subjects), Ali et al [16] (75 subjects), Gupta et al [17] (100 subjects), and Jacob et al [3] (32 cadaveric skulls) had done OF analysis among Indian population from various states, but the sample sizes were limited and asymmetry analysis was incomplete in most. In our study, we have tried to focus on the distribution of Keros types and various asymmetry parameters in detail and is more comprehensive than the previous Indian studies.…”

Section: Discussionmentioning

confidence: 99%

Olfactory fossa depth: CT analysis of 1200 patients

Babu

Nair

Kuriakose

2018

Indian Journal of Radiology and Imaging

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Background:Olfactory fossa (OF) is a depression in anterior cranial cavity whose floor is formed by cribriform plate of ethmoid. Lateral lamella, which forms its lateral boundary, is a thin plate of bone and is at risk of injury during functional endoscopic sinus surgery, especially when fossa is deep/asymmetric.Aims:To measure the variations in the depth of OF and categorize Kerala population as per Keros classification using computed tomography (CT).Settings and Design:This study was conducted in our institution from January 2016 to August 2017. Patients >16 years of age undergoing CT scan of paranasal sinuses (PNS) were included.Materials and Methods:Coronal PNS CT scan studies of 1200 patients were reviewed. The depth of OF was measured from vertical height of lateral lamella.Statistical Methods:Results were analyzed according to gender and laterality using independent sample t-test and Chi-square test.Results:The mean depth of OF was 5.26 ± 1.69 mm. Statistically significant difference was seen in the mean depth of OF between males and females but not between right and left sides. Keros type I was found on 420 sides (17.5%), type II in 1790 (74.6%), and type III on 190 sides (7.9%). Type III Keros was more on the right (9%) than left (6.8%) side, more in males (9.5%) than females (5.9%), and more among males on the right side (11.4%). Asymmetry in OF depth between two sides was seen in 75% of subjects.Conclusion:Prevalence of the dangerous type III OF, even though low, is significant especially among males and on the right side. Therefore, preoperative assessment of OF depth must be done to reduce iatrogenic complications.

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Radiological Observation of Ethmoid Roof on Basis of Keros Classification and Its Application in Endonasal Surgery

Cited by 9 publications

References 10 publications

CBCT Assessment of Ethmoid Roof Variations through Keros, Gera, and TMS Classifications

CBCT Assessment of Ethmoid Roof Variations through Keros, Gera, and TMS Classifications

Normal anatomic variants of paranasal sinus region studied by computed tomography

Olfactory fossa depth: CT analysis of 1200 patients

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