Lateral Lamella Of Cribriform Plate Research Articles

Multidetector Computed Tomography Used in Evaluation of Olfactory Fossa Depth in a Tertiary Hospital in Eastern Region of Nepal: A Descriptive Cross-sectional Study.

Olfactory fossa (OF) is a depression in most infero-medial portion of anterior cranial fossa formed by cribriform plate, crista galli and lateral lamella of cribriform plate (LLCP). LLCP being thinnest and extremely variable parts, more prone for iatrogenic injury during sinus surgery in case of asymmetric and deep OF. Multidetector computed tomography (MDCT) is frequently used imaging modality in the evaluation of paranasal sinus. The objective of the study is to classify the OF depth according to the Keros classification. In this ethically approved prospective, cross-sectional descriptive study, CT scan was done in 530 consecutive patients from February 2022 to July 2023. Coronal CT images of paranasal sinuses and nose were used to measure the OF depth. The data collected was analyzed using SPSS. Out of 530 patients included in this study, 310 (58.49%) were male and 220 (41.51%) were female with mean age of 40.46±11.56 years. Total of 1060 olfactory fossa were analyzed with mean depth of 4.96±1.88 mm. In our study, 310 (29.24%) had type I, 730 (68.88%) had type II and 20 (1.88%) had type III according to Keros classification. Keros type II OF is more common. The dangerous type III OF having low prevalence, more commonly seen on right side and in males.

A Study of Skull Base According to Gera Classification in a Korean Population

Background and Objectives The leakage of cerebrospinal fluid due to damage to the ethmoid roof and cribriform plate (CP) is one of the most serious complications of endoscopic sinus surgery (ESS). For the risk of skull base injury during ESS, the Keros classification has been widely used, but recently the Gera classification has been introduced as a tool for risk assessment. This study evaluated the risk of skull base damage using the Gera classification in Koreans.Subjects and Method We analyzed 592 left and right sides of 296 paranasal sinus CTs, and measure the angle between the lateral lamella of CP and the lateral extension of the horizontal plane passing through CP, namely the Gera angle. The angles were classified into three categories: the type I (>80°, low risk), type II (45° to 80°, medium risk), and type III (<45°, high risk).Results The type III, which is vulnerable to skull base damage, accounted for 11.7% of the study subjects. The Gera angle in females (64.0°±12.3°) was greater than that in males (61.3°± 14.0°), showing a significant gender difference (p=0.015). Although there was no difference between the left and the right side of the Gera angle (p=0.155), there was a significant difference between the left and the right side in the Gera classification (p<0.001). Age and the Gera angle showed a negative correlation (r=-0.116, p=0.005).Conclusion The type III of the Gera classification was observed in 11.7% of the total study group. For the type III, extra care is required during ESS.

Assessment of Olfactory Fossa Depth based on Keros Classification using Computerised tomography (Ct) in Age Groups of Both Genders

Objective: Keros classification based assessment of olfactory fossa depth in different age groups of both genders using computerized tomography (CT)
 Methodology: Cross sectional study done at Ziauddin university, Clifton, Karachi. Sample size was 270 adults including 160 males & 110 females. The assessment of depth of Olfactory fossa was carried out by measuring the height of lateral lamella of cribriform plate on CT images.
 Result: Olfactory fossa of 270 patients from both sides of both genders were classified according to Keros classification. We found Type II to be the most frequent on both sides in both genders. No significant difference in olfactory fossa depth was found when compared in different age groups.
 Conclusion: The present study shows that vast majority of the population comes under Keros type II & type III thus emphasizing the need of pre-operative radiological assessment. Association of right & left olfactory fossa depth in different age groups was found to be insignificant.

Analysis of Olfactory Fossa Anatomy using Cone Beam Computed Tomography

Introduction: Olfactory fossa is an important structure in the anterior skull base. It is made of Lateral Lamella of Cribriform Plate (LLCP) and fovea ethmoidalis which are very delicate parts that can get damaged during surgical procedures causing numerous serious complications. To avoid such complications, the knowledge of anatomical variations of these parts is mandatory. As there are very few studies which have used Cone Beam Computed Tomography for evaluation of olfactory fossa, we have assessed the olfactory fossa with the help of Kero’s and Gera’s classification for lateral lamella of cribriform plate. Aim: To evaluate the anatomy of olfactory fossa using Cone beam computed tomography. Materials and Methods: A retrospective observational study was conducted in the Department of Oral Medicine and Radiology, from 1st January 2021 to September 2021. CBCT scans of 107 adults were analysed to evaluate the height of lateral lamella of cribriform plate according to Kero’s classification and the angle between the LLCP and the true horizontal plane according to Gera’s classification. Comparison of height of lateral lamella (mm) and Gera angle (degree) among right and left sides were done using Student’s Independent t-test. The comparison of Gera angle with Kero’s type was analysed by one way Analysis of Variance (ANOVA) test. Chi-square test was performed to assess categorical data on the right and left sides. Results: A total of 107 CBCT scans consisting of 59 males (55.14%) and 48 females (44.86%) were included in the study. The mean age of the study population was 31.60±11.17 years. Kero’s type II (69.6%) and Gera’s class II (92.1%) LLCP were found to be most commonly seen. The Gera angle on right side (60.26±9.84) was greater than on left side (56.38±10.16) which was statistically significant (p-value=0.005). On right side, Kero’s type II was more common in males (71.2%) and on left side, Kero’s type II was more common in females (77.1%). Conclusion: Kero’s type II Olfactory fossa (OF) was found as most common type, with no significant difference between gender and /or side. Similarly, class II Gera angle was most common and the values were higher on right side.

Sexual Dimorphism and Clinical Relevance of Thickness and Angulation of Lateral Lamella of Cribriform Plate-A Multidtector Computed Tomographic Study

Background: The aim of this study was to establish the morphometry and sexual dimorphism of laterallamella of cribriform plate in the North Karnataka region.Method: Six hundred and forty four (644) Multidetector computed tomographic scans were collectedfrom North Karnataka region and analyzed by using RadiAnt DICOM Viewer. The thickness andangulation of lateral lamella of cribriform plate of olfactory fossa were calculated on both the sides inboth genders. Statistical analysis was done by using Student unpaired‘t’ test.Conclusion: There was statistically significant difference in the angle of lateral lamella of cribriformplate when compared between right side (mean=106.25˚) and left side (mean=109.38˚) in males.There was no such difference among females. Statistically significant difference was observed in theangle of lateral lamella of cribriform plate in male patients (mean=106.25˚) when compared to femalepatients (mean=109.61˚). The thickness of lateral lamella of cribriform plate was not significant whencompared between two sides in males and females. Hence, these variations in the morphometry of thelateral lamella of cribriform plate of ethmoid bone will be of importance for the surgeons in Functionalendoscopic sinus surgeries and anterior skull base surgeries.

Anatomical Variations of Anterior Ethmoidal Foramen and Cribriform Plate: Relations With Sex.

Position of anterior ethmoidal artery and height of lateral lamella of cribriform plate (LLCP) represent critical variants in endoscopy.In 200 maxillofacial computed tomography scans of patients the position of anterior ethmoidal foramen (AEF) in relation to ethmoid roof was recorded. The height of LLCP was measured and classified according to Keros classification.Differences in AEF position and distribution of Keros types, and LLCP height according to sex were assessed through chi-square test (P < 0.05) and 1-way analysis of covariance (ANCOVA) test, respectively (P < 0.05). Differences in LLCP height according to different AEF position were assessed through Mann-Whitney test (P < 0.05).No differences were observed in prevalence of AEF exposure according to sex (P > 0.05); LLCP height was higher in males than in females, with a higher frequency of Keros type 3 (P < 0.05). Moreover, subjects with AEF exposure had a significantly higher LLCP height (P < 0.01).Results highlighted innovative data useful for improving the knowledge of these sensitive variants.

Lateral Lamella of Cribriform Plate (LLCP): A Computed Tomography Radiological Analysis.

Spectrum of disease involves nasal passage and paranasal sinuses termed as sinonasal disease. CT is superior to other imaging modalities in the assessment of the paranasal sinuses (PNS) pathology. Functional Endoscopic Sinus Surgery (FESS) is the common modality of treatment for diseases of nose and PNS. Coronal CT images closely correlates with the surgical approach. Therefore, CT is the preferred study before FESS. The lateral lamella of cribriform plate (LLCP) is the thinnest bone in the anterior skull base and most vulnerable parts of the skull base for iatrogenic complication during FESS. Therefore, preoperative evaluation of LLCP is importance in a successful FESS. The study focused on the vertical height of the LLCP and the angulation of LLCP with CP. This study was performed retrospectively on CT images of 600 adult subjects. Chi square test and pearson correlation were used for data analysis. Type II is most prevalent type of Kero's type. There is a significant correlation between Kero's classification and Gera's classification. A positive correlation found between the vertical height of LLCP with its angle formed by CP and the correlation was found to be significant. Assessment on LLCP in its 2 aspect both vertical height of LLCP and its sloping with CP certainly gives a map to the surgeon during FESS and to improve the safety profile of the procedure.

Radio anatomical analysis of positional relation between anterior ethmoid artery canal and ethmoid skull base in correlation with olfactory fossa

Skull base (SB) injuries happens mostly either in the thinnest or the least resistant part of skull base. The lateral lamella of cribriform plate is one of the common sites of injury during endoscopic anterior skull base surgeries. The anterior ethmoid artery (AEA) visualization is considered as a significant anatomical landmark in such surgeries. Studies correlating their positional relation with morphology of olfactory fossa remains limited. This study aims to look into the relation of AEA to that of SB in different types of olfactory fossa morphology.A retrospective radiological study was done on 100 coronal CT images from patients who were subjected to paranasal CT imaging. In bone window of coronal CT scans, the position of AEA in relation to SB was noted and the vertical distance between them was measured. Based on the distance of AEA from SB, 3 groups were subdivided as follows: Group A - &amp;#60; 2.5 mm, Group B – 2.5 to 5 mm and Group C - &amp;#62; 5 mm. The depth of the olfactory fossa was measured and categorized according to Keros classification.Out of 200 sides, AEA was found below SB in 167 out of 200 (83.5%) with majority belonging to Group A (101 out of 167). Keros type II was commonly observed among all the groups. The position of AEA below SB was seen at a greater frequency as the height of SB increased with the Keros classification and was statistically significant (P = .006)The knowledge of presence of anterior ethmoid artery outside the skull base with long lateral lamella preoperatively would help the surgeon to avoid intraoperative complications during endoscopic skull base or sinus surgeries.

Anterior Ethmoidal Artery: A Computed Tomography Analysis and New Classifications.

Objective to determine the anterior ethmoidal artery (AEA) anatomy and variations by computed tomography (CT) in adult and their relations to and presents new AEA classifications. Methods One hundred and fifty paranasal CT scans (300 sides) were included. Axial images were acquired with multiplanar reformates to obtain delicate details in coronal and sagittal planes. Results One hundred and forty-four AEAs canal (48%), 293 AEAs foramen (97.7%), and 229 AEAs sulcus could be detected (76.3%). The mean AEA intranasal length was 6.7 ± 1.27 mm (range: 4.24-10.6 mm). The mean angle between AEA and lamina papyracea was 105.49 ± 9.28 degrees (range: 76.41-129.76 degrees). Of them, 95.8% AEAs had an angle with lamina >90 degrees, while 4.2% had angle <90 degrees. The mean angle between AEA and lateral lamella of cribriform plate was 103.95 ± 13.08 degrees (range: 65.57-141.36 degrees). Of them, 87.5% AEAs had an angle >90 degrees and 12.5% had an angle <90 degrees. The mean distance between AEA and skull base was 1.37 ± 1.98 mm (range: 0-8.35 mm). The AEA types in relation to skull base was type 1 (0-2 mm from skull base; 64.6%), type 2 (2-4 mm; 22.2%), type 3 (4-6 mm; 11.1%), and type 4 (>6 mm; 2.1%). The mean distance between the AEA and frontal sinus ostium was 9.17 ± 4.72 mm (range: 0-25.36 mm). AEA classification according to distance from AEA to frontal sinus ostium was 17.4% type 1 (<5 mm), 41.7% type 2 (5-10 mm), 31.9% type 3 (10-15 mm), and 9% type 4 (>15 mm). Conclusion Provided AEA details improve surgeons' awareness of AEA variations in the endoscopic field and can help residents in training.

Radiological Analysis of Olfactory Fossa Depth: A Tertiary Care Hospital Based Study

Introduction: Computed tomogram (CT) of nose and paranasal sinuses provides the detailed knowledge of depth of olfactory fossa as per Keros' classification, which is important in endoscopic sinus surgery.&#x0D; Objective: To analyze the types and frequency of depth of olfactory fossa in Nepalese population.&#x0D; Methodology: This was a longitudinal study conducted from 1 May to 30 August 2018. Coronal CT scans of nose and paranasal sinuses were taken for analysis of olfactory fossa depth. The landmarks like infraorbital foramen, point of articulation of medial ethmoidal roof with lateral lamella of cribriform plate (MERP) and lowest point on the cribriform plate (CP) were taken. The lateral lamella of cribriform plate (LLCP) was calculated by subtracting CP height from MERP height (MERP-CP = LLCP).&#x0D; Results: There were total 101 patients included. The distribution of age was 33.72 ± 15.15 years. The keros' type I was the most common (86.1%). Regarding the olfactory fossa depth, right side was deeper in male whereas in females, the left side was deeper, but overall right side was deeper in 52(51.5%) patients.&#x0D; Conclusions: Type I Keros' was the most common whereas type III Keros' was the least common. A deep olfactory fossa is more common on right.

Anatomical variations of anterior ethmoidal artery and their significance in endoscopic sinus surgery: a systematic review.

Anterior ethmoidal artery (AEA) is at risk of injury in endoscopic sinus surgery due to its location. The aim of this review was to assess the anatomical variations of AEA and their significance. A literature search was performed on PUBMED, SCOPUS AND EMBASE. The following keywords were used: ethmoidal artery; anterior ethmoidal artery; anterior ethmoidal canal; ethmoid sinus; ethmoid roof; skull base. The search was conducted over a period of 6 months between October 2016 and April 2017. 105 articles were retrieved. 76 articles which were either case reports or unrelated topics were excluded. Out of the 29 full text articles retrieved, 16 articles were selected; 3 were cadaveric dissection, 5 combined cadaveric dissection and computed tomography (CT) and the rest were of CT studies. All studies were of level III evidence and a total of 1985 arteries were studied. Its position at the skull base was influenced by the presence of supraorbital ethmoid cell (SOEC) and length of the lateral lamella of cribriform plate (LLCP). Inter population morphological variations contribute to the anatomical variations. The average diameter of AEA was 0.80mm and the intranasal length was 5.82mm. 79.2% was found between the second and third lamellae, 12.0% in the third lamella, 6% posterior to third lamella and 1.2% in the second lamella. Extra precaution should be taken in the presence of a well-pneumatized SOEC and a long LLCP as AEA tends to run freely below skull base.

A computerized tomographic study of height of ethmoidal skull base

Background: During Endoscopic Sinus Surgeries (ESS), the most important anatomical structures that need preoperative visualisation and evaluation are the lateral lamella and ethmoidal skull base as many reports of complications due to injury of these structures exist. Ethmoidal Skull Base (ESB) extends from the superior attachment of lateral lamella of cribriform plate to the junction of the lamina papyracea. The aim is to study and evaluate ESB using coronal sinus CT images. Methods: Sixty coronal sinus CT scan images at the level of visualization of anterior ethmoidal artery canal were taken for studying the ESB on both sides. A horizontal line bisecting the orbit was taken as the base line reference for inferior extent. The height of the ESB was measured and classified into high, moderate and low ESB by taking 7 mm as upper limit and 4 mm as lower limit. Mean height of ESB in the study group was computed and its difference among gender and sides were noted and statistically analysed. Results: ESB varied between 3.7 mm to 15.4 mm with mean height of 10.05 mm. Low ESB was found only in females and there was no statistically significant side asymmetry of ESB height. Conclusions: Preoperative recognition of low ESB and alerting the surgeon of the potential for iatrogenic injury by measuring the height of ESB needs to become a standard practice in order to minimize the complications during ESS.

Cerebrospinal fluid rhinorrhea: etiology, site of leakage and endoscopic management.

To determine the etiology and site of leak of cerebrospinal fluid (CSF) rhinorrhea and the surgical efficacy of Functional Endoscopic Sinus Surgery (FESS), in closing the defect of CSF leak by different graft materials. Case series. Department of ENT-Head and Neck Surgery, Dow University of Health Sciences, Karachi, from September 2005 to December 2008. Clinical and pathological records of 23 patients who were diagnosed to have cerebrospinal fluid leak and managed by endoscopic approach were studied. Different graft materials alone or in combination were used endoscopically to seal the CSF leak. Results were obtained in terms of successful closure of the CSF leak, as evidenced by cessation of CSF rhinorrhea. Iatrogenic trauma, due to previous surgery, was the commonest cause in (n=9, 39%) patients. Lateral lamella of cribriform plate (fovea ethmoidalis) was the commonest site of leak (n=10, 43.5%). The leak was closed solely by fat in 15 (65.2%) cases, combination of fat and middle turbinate mucosa (two layered) in 7 (30.4%) patients and temporalis fascia only in one patient (4.3%). Successful closure of the CSF leak in the first attempt was achieved in 22 (95.6%) patients. Success rate achieved by endoscopic approach in this study was high. However, more data is required to prove the superiority of FESS over intracranial approach for management of CSF rhinorrhea.

Computed tomographic Assessment of Lateral Lamella of Cribiform Plate and Comparison of Depth of Olfactory Fossa

Endoscopic sinus surgery is an upcoming branch in rhinological practice but with some major risks since it has to play around the skull base area. Lateral lamella of cribriform plate is the thinnest area of the skull base. Thus this study is undertaken to evaluate the height of lateral lamella of cribriform plate and the depth of olfactory fossae by the help of computed tomographic images. Computed tomographic study of 50 patients was done in Advanced Imaging and Diagnostic center, Kathmandu Medical College. Coronal sections at the centre of infra-orbital foramina were taken as reference slide. The height of cribriform plate point was subtracted from the height of medial ethmoidal roof point to measure the length of lateral lamella of cribriform plates on both sides. The median height of LLCP in 100 slides was 2.8 mm. LLCP height was 0 to 3.9 mm in 86 slides, 4 to 7 mm in 12 slides and greater than 7mm in 2 slides. The LLCP length was greater in right side in 28 (56%) patients and was greater in left side in 19 (38%) patients. It was equal in both sides in only three patients (6%). As regards the length of LLCP; 0 to 3.9 mm length was most common. The olfactory fossa depth was more in the right side compared to the left side. Thus, right side is more vulnerable to injury during surgery. Thus adequate caution has to be exercised by the rhinological surgeon during endoscopic sinus surgery.