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ABSTRACT: Imaging of the anterior skull base and paranasal sinuses is essential before surgery of the nose and paranasal sinuses. It is important to know individual anatomical variations to define a "dangerous ethmoid" to prevent complications such as considerable bleeding or injury to the brain. This study aimed to analyze the relevant parameters with special regard to age-dependent differences.
This was a retrospective, single center study of 865 patients. Data from cone beam computed tomography (CBCT) of 116 patients less than 18 years of age and 749 adult patients were analyzed. Keros type, the course of the anterior ethmoid artery, the course of the uncinate process and the angle between the lateral lamella and the cribriform of the olfactory fossa were evaluated.
Different frequencies of the course of the uncinate process between young and adult persons could be shown: onset at the lamina papyracea 67% vs. 64%; onset at the skull base, 22% vs. 26%; and onset at the middle turbinate, 11% vs. 10%. Differences in the course of the anterior ethmoid artery could be evaluated in the same way: course at the skull base, 49% vs. 44%; free course with a distance to the skull base of less than 3mm, 11% vs. 19%; and free course with a distance to the skull base more than 3mm, 40% vs. 37%. Significant differences could be found in the frequencies of the height of the olfactory fossa: Keros type I, 28% vs. 16%; Keros type II, 51% vs. 60%; and Keros type III, 21% vs. 24%. The angle between the lateral lamella and the cribriform plate showed significant differences dependent on the course of the anterior ethmoid artery (skull base=123° vs. distance<3mm=117° vs. distance>3mm=110°) and dependent on the height of the olfactory fossa (Keros type I=135° vs. Keros type II=117° vs. Keros type III=104°). Analysis of the angle as a factor of age and Keros type showed a significant difference in Keros type I (125° vs. 132°) and Keros type II (105° vs. 110°).
Cone beam computed tomography (CBCT) of the anterior skull base allows the assessment of individual anatomical-radiological risk profiles and the identification of a "dangerous ethmoid". Significant age-dependent differences in the frequencies of anatomic landmarks and the angles of the ethmoid roof could be evaluated and led to significantly different risk profiles between children and adults.
International journal of pediatric otorhinolaryngology 03/2012; 76(6):822-8. · 0.85 Impact Factor
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ABSTRACT: The sphenoid sinus is a frequent target of paranasal sinus surgery. Because of the high risk of injuring the surrounding structures (e.g. internal carotid artery, optical nerve) a preoperative imaging is absolutely necessary.
To analyze the possibilities of cone-beam computed tomography (CBCT), which is especially quite a new technique in ENT, in the evaluation of the sphenoid sinus, its surrounding structures, and the corresponding anatomical variations.
This was a retrospective, single-centre study of 580 patients (1160 sides = cases). The Accu-I-Tomo-F17 was used. Pneumatization of sphenoid sinus, course of internal artery, course of optical nerve, and dehiscence of the bony canals were evaluated.
In the case of pneumatization a type I (completely missing or minimal sphenoid sinus) was found in two patients (0.3%), type II (posterior wall of sphenoid sinus is in front of the anterior wall of the sella) in 38 patients (6.6%), type III (posterior wall is between anterior and posterior wall of sella) in 332 patients (57,2%), type IVa (posterior wall is behind the posterior wall of sella without air dorsal the sella) in 104 patients (17.9%), and type IVb (similar to type IVa but with air dorsal the sella) in 104 patients (17.9%). In 1025 cases (89.5%) a smooth course of the internal carotid artery was found whereas a free course could be detected in 120 cases (10.5%). Defects of the bony canal of the optical nerve were found in 16.7% and of the internal carotid artery in 2.7% of the cases. The optical nerve showed a free course through the sphenoid in 151 cases (13.7%) and a smooth course in 1007 cases (87.0%).
CBCT could evaluate all relevant anatomic structures and answer the questions of different anatomical variants. A modified classification of the pneumatization of the sphenoid sinus could be described. Frequencies of anatomical variations are in accordance with the current literature of CT research.
Acta Radiologica 03/2012; 53(2):214-9. · 1.37 Impact Factor
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ABSTRACT: A cone beam tomography (CBT) examination of the olfactory area with its different variants allows development of an individual anatomical-radiological risk profile of the ethmoid and the identification of so-called 'dangerous ethmoids.'
Preoperative imaging performed with high-resolution CBT is imperative for analysis of the risk of injuring the olfactory fossa during sinus surgery. This study aimed to analyze the relevant parameters.
This was a retrospective, single-center study of 141 patients. The Accu-I-Tomo F17 was used. Keros type, the point of the anterior ethmoid artery, and the angle between the lateral lamella and the cribriform plate (α(lc)) were evaluated.
The Keros types were distributed as follows: type I, 13% (α(lc): 131°); type II, 64% (α(lc): 116°); type III, 23% (α(lc): 108°) (p < 0.001). The angle of the olfactory fossa and the position of the anterior ethmoid artery (free course: α(lc)=112° vs integrated into the skull base: α(lc)= 120°) was significantly different.
Surgical procedures in Keros type III where the height of the lateral lamella is much longer than in type II or type I, with an angle of nearly 107° between the lateral lamella and the cribriform plate, are expected to be safer in comparison with Keros type II with 116° and Keros type I with 131°.
Acta oto-laryngologica 01/2011; 131(1):72-8. · 0.98 Impact Factor
