Is the Keros classification alone enough to identify patients with the ‘dangerous ethmoid’? An anatomical study

Skorek, Andrzej; Tretiakow, Dmitry; Szmuda, Tomasz; Przewoźny, Tomasz

doi:10.1080/00016489.2016.1225316

Cited by 24 publications

(32 citation statements)

References 18 publications

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“…Similar findings to Keros's study have been reported in in various countries such as South Korea [15], Turkey [18], Turkey [19], Turkey [20], Turkey [21], Turkey [22] , Thailand [23], Brazil [10], Germany [24], Egypt [25], Pakistan [26], Poland [27], Saudi Arabia [28], India [29], India [30] , and Iran [31]. Unlike to Keros study [9], and similar studies [10,15,[18][19][20][21][22][23][24][25][26][27][28][29][30][31] our findings showed that Type I is the most common type (71.0%), followed by Type II (27.4%) and the Type III (1.6%) of the cases, respectively. However, our findings inline to results reported in studies from Philippine [16], USA [32], UK [33], Nepal [34], Malaysia [35], and Egypt [36] which confirms that the Keros type I is the most common.…”

Section: Discussionsupporting

confidence: 90%

“…Likewise to several studies conducted in Turkey [19, [22], Poland [27], and Iran [31], our study found no statistically significant difference between males and females in all Keros types on both sides. In contrast, other studies from Philippine [16], Malaysia [35] and India [30] found a statistically significant difference in Keros types II between males and females and some other studies from Egypt [25], Saudi Arabia [28], and Pakistan [26] found a statistically significant difference between males and females in Keros type I.…”

Section: Discussionsupporting

confidence: 81%

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Computed tomography assessment of the ethmoid roof based on Keros classification in Iraqi patients undergoing functional endoscopic sinus surgery

2021

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Background: Among the most popular methods employed to classify the depth of the olfactory fossa is Keros classification. This study aims to assess Keros classification of the ethmoid roof, any possible association between Keros types and gender, and the incidence of asymmetry between right and left sides among Iraqi patients. Methods: A retrospective cross-sectional study was conducted at Al-Shaheed Gazi Al-Hariri Teaching Hospital, Medical City, Baghdad, Iraq. The archived reports and the CT scans images (nose and paranasal sinuses) of 126 patients who have undergone functional endoscopic sinus surgery between January 2019 and January 2020 were reviewed. Univariate and bivariate statistical analysis was performed using SPSS version 24. The statistically significant was considered at less than 0.05. Results: More than half of patients were females (54.0%) with a mean age of 31.52 ± 11.38 (SD) years (range: 10-57 years). Among the total patients, the mean depth of olfactory fossa (OF) was 3.58 ± 0.02 mm. Results showed that Keros type I was the most common type (71.0%), followed by type II (27.4%) and type III (1.6%) respectively. The difference in the olfactory fossa depth between the right and left sides was ≥ 1 mm in 16 (12.7%) patients and < 1 mm in 110 (87.3%) patients. Moreover, there was no significant relation between symmetry/asymmetry and gender ( p-value > 0.05). Conclusion: Keros type I was the most common type, which carries the lowest risk of inadvertent intracranial injury during endoscopic sinus surgery; besides the relatively low percentage of asymmetry in the depth of the two olfactory fossae among patients, surgeons should always be cautious during surgery to avoid iatrogenic injury concerning the thin lateral lamella of the cribriform plate.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionsupporting

confidence: 81%

Computed tomography assessment of the ethmoid roof based on Keros classification in Iraqi patients undergoing functional endoscopic sinus surgery

2021

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“…www.nature.com/scientificreports www.nature.com/scientificreports/ and left side contributes to the asymmetry in the ER configuration. In a radiological study by Skorek et al 12 , they found that Keros classification alone is not enough to identify the high-risk area at the skull base and the "dangerous ethmoids' . They recommended a classification that is based on the distance of olfactory fossa to both medial wall of orbit and the medial wall of middle turbinate as most ESS dissection occurs lateral to the middle turbinate.…”

Section: Discussionmentioning

confidence: 99%

A new radiological classification for the risk assessment of anterior skull base injury in endoscopic sinus surgery

Abdullah

Chew

Aziz

et al. 2020

Sci Rep

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Keros and Gera classifications are widely used to assess the risk of skull base injury during endoscopic sinus surgery. Although, both classifications are useful preoperatively to stratify risk of patients going for surgery, it is not practical to measure the respective lengths during surgery. In this study, we aimed to propose a new radiological classification (Thailand-Malaysia-Singapore (TMS)) to assess the anatomical risk of anterior skull base injury using the orbital floor (OF) as a reference. A total of 150 computed tomography images of paranasal sinuses (300 sides) were reviewed. The TMS classification was categorized into 3 types by measuring OF to cribriform plate and OF to ethmoid roof. Most patients were classified as TMS type 1, Keros type 2 and Gera class II, followed by patients classified as TMS type 3, Keros type 1 and Gera class 1. TMS has significant correlation with Keros classification (p < 0.05). There was no significant correlation between Keros and Gera classifications (p = 0.33) and between TMS and Gera classifications (p = 0.80). The TMS classification has potential to be used for risk assessment of skull base injury among patients undergoing ESS. It serves as an additional assessment besides the Keros and Gera classifications.

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“…Several authors suggested that the risk of iatrogenic LLCP injury increases with the olfactory cleft depth (6)(7) . For this reason, the classification proposed in 1962 by Keros (8) is still the most commonly used today to estimate the risk of iatrogenic CSF-L.…”

Section: Introductionmentioning

confidence: 99%

“…Patients with Keros type 3 are supposed to have a greater risk of intracranial entry since the more pronounced depth of the cribriform cleft and the thinness of its bony wall make this area more susceptible to iatrogenic injuries (2,7) . Even though widely used, several authors highlighted the limitations of this classification system in fully describing the shape of the skull base and predicting the intracranial entry risk (6,(9)(10)(11)(12)(13) . Recently, our group proposed a new classification system of the anterior skull base anatomy based on the angle formed between the LLCP and the lateral extension of an horizontal plane passing through the cribriform plate (Gera classification).…”

Section: Introductionmentioning

confidence: 99%

Horizontal lateral lamella as a risk factor for iatrogenic cerebrospinal fluid leak. Clinical retrospective evaluation of 24 cases

Preti¹,

Mozzanica²,

Gera³

et al. 2018

Rhin

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Background: Several authors highlighted the limitations of the Keros classification system in predicting intracranial entry risk. Recently, our group proposed a new classification system based on the angle formed between the lateral lamella of the cribriform plate (LLCP) and the continuation of an horizontal plane passing through the cribriform plate (Gera classification). The aim of this study was to analyze whether the risk of iatrogenic cerebrospinal fluid leak (CSF-L) was better predicted by Keros or Gera classification. Methodology: The pre-operative CT scans of 24 patients (CSF-L group) who suffered from iatrogenic CSF-L during endoscopic sinus surgery (ESS) were compared to those obtained from a group of 100 patients who underwent uneventful ESS (control group). The skull base measurements as well as the distribution of Keros and Gera classes in the 2 groups were analyzed. Results: No difference in the distribution of Keros classes or in the depth of the cribriform plate between CSF-L and control group were demonstrated. On the contrary, significant differences in the distribution of Gera classes and in the degree of the angle formed by the LLCP and the continuation of the horizontal plane passing through the cribriform plate were found. In particular, according to Gera classification system, 19 out of 24 patients in the CSF-L group were considered at risk for iatrogenic CSF-L. Conclusions: Gera classification system might be more sensitive to anatomical variations associated with CSF-L than the Keros' one, further suggesting the application of the former during the preoperative CT scan evaluation.

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Is the Keros classification alone enough to identify patients with the ‘dangerous ethmoid’? An anatomical study

Abstract: Keros type I, II, and III was noted in 9.2%, 75.8%, and 15.0% of cases, respectively. Despite some statistically significant correlations, it was not possible to identify the patient age, sex, and side of body clearly correlating with the critical measurements.

Cited by 24 publications

References 18 publications

Computed tomography assessment of the ethmoid roof based on Keros classification in Iraqi patients undergoing functional endoscopic sinus surgery

Computed tomography assessment of the ethmoid roof based on Keros classification in Iraqi patients undergoing functional endoscopic sinus surgery

A new radiological classification for the risk assessment of anterior skull base injury in endoscopic sinus surgery

Horizontal lateral lamella as a risk factor for iatrogenic cerebrospinal fluid leak. Clinical retrospective evaluation of 24 cases

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