CT Findings in Revision Endoscopic Sinus Surgery / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: When performing a revision endoscopic sinus surgery, operators should pay close attention due to the altered sinonasal anatomy or defects of anatomical landmarks. Careful preoperative evaluation of altered anatomy is important, however, little has been reported on its structural changes. We investigated status of anatomical structures and mucosal pathology by reviewing OMU CT in revision sinus surgeries. MATERIALS AND METHODS: A total of 117 operated sides (right: 59, left: 58) from 62 patients who received revision endoscopic sinus surgeries were evaluated. They had history of previous sinus surgeries such as Caldwell-Luc operation, polypectomy, or endoscopic sinus surgery. We investigated the following 5 parameters by reviewing preoperative OMU CT; Sinus mucosal pathology, bony thickening, absence of superior or middle turbinate, structural changes of superior or middle turbinate, and defects of anatomical landmarks. RESULTS: Sinus mucosal pathology was most commonly found in the maxillary sinuses, and was followed by the anterior ethmoid, the posterior ethmoid, the frontal, and the sphenoid sinuses. Out of 117 sides, 47 showed bony thickening and 7 showed absence of superior or middle turbinate. Eleven revealed structural changes in the superior or middle turbinate, and three showed defects in the lamina papyracea. However, there was no complete absence of the middle or superior turbinates, all of which were partially preserved. CONCLUSION: Significant bony thickening, defects or changes of anatomical structures and associated mucosal pathology were frequently found in revision endoscopic sinus surgeries. Preoperative review of OMU CT, identification of structural changes, and close attention during surgery would be necessary.

The Clinical Usefulness of Axial OMU CT in ESS for Chronic Sinusitis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: OMU CT scans are taken on a direct coronal plane for chronic sinusitis and thus allows evaluation only from the coronal plane. However, axial OMU CT provides view of the surrounding vital structures, variation of air cells, and the anterior to posterior relations of structures associated with chronic sinusitis. We investigated the clinical usefulness of axial OMU CT in chronic sinusitis. MATERIALS AND METHODS: A prospective study was performed in 100 sinuses of 50 patients with chronic sinusitis who underwent endoscopic sinus surgery from May through July of 1998. RESULTS: We observed that axial OMU CT has the advantage of evaluating the outline of the lateral lamella of lamina cribrosa, anterior and posterior ethmoid canal, optic nerve in sphenoid sinus, internal carotid artery in sphenoid sinus, Onodi cell, and anterior to posterior relations of these structures. CONCLUSION: We found that, in chronic sinusitis, axial OMU CT is effective in evaluating the important vital structures, normal variation, and the relations between the structures and that it can help prevent complication during ESS. We therefore recommend axial OMU CT to be included in the routine radiological evaluation for ESS in chronic sinusitis.

The Evaluation and Measurement of Anterior Ethmoidal Canal in Axial OMU CT / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The anterior ethmoid canal is the important surgical landmark in endoscopic sinus surgery, intranasal ethmoidectomy, and frontal sinus surgery. However it is not enough to evaluate the anterior ethmoid canal by coronal OMU CT, especially relating anterior to posterior relationship of the anterior ethmoid canal. The pulpose of this study is to evaluate the anterior ethmoid canal in 1 mm axial OMU CT and measure the five parameters relating the anterior ethmoid canal. MATERIALS AND METHODS: A prospective study was performed in 100 sinuses of 50 patients with chronic sinusitis who underwent endoscopic sinus surgery from May through July of 1998. RESULTS: The anterior ethmoid canal is well demonstrated by 1 mm axial OMU CT. The average of five parameters are 6.2+/-1.5 mm, 6.4+/-4.3 mm, 18.5+/-3.9 mm, 26.5+/-5.6 mm, 24.6+/-14.6degrees. However, there is no difference between the right and left side statistically. We observed that the anterior ethmoid canal is located just posterior to the frontal recess without anterior ethmoid air cell in front of the antirior ethmoid canal in 23%. CONCLUSION: The anterior ethmoid canal is well remarked by the 1 mm axial OMU CT. The length and directional angle of the anterior ethmoid canal is individually variable and there is no anterior ethmoid air cell in front of the anterior ethmoid canal in 23%. In these cases, the anterior ethmoid canal is more likely to be injured. So axial OMU CT may be useful in the radiologic evaluation for endoscopic sinus surgery in chronic sinusitis.

Computerized Tomographic Evaluation of the Incidence of Bony Defects of Lateral Lamella of the Cribriform Plate in the Patients with Chronic Paranasal Sinusitis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Performing ESS, in order to gain a better understanding ofthe topographical anatomy of the paranasal sinus, paticularly the lateral lamella of cribriform plate (LLCP), is of paramount importance for avoiding inadvertent injury of intracranial compartment. The purpose of this study was to evaluate the incidence of bony defects and radiologic characteristics in the LLCP detectable using coronal CT scan. MATERIALS AND METHOD: The coronal CT scans of 205 subjects with ages ranging from 8 to 65 years were retrospectively reviewed. The overall incidence of bony defects particularly in terms of subjects' age and depth of cribriform plate were analyzed. RESULTS: The bony defects of lateral lamella were found in 72% of the subjects studied, among them 35% had unilateral type, whereas 65% had bilateral types. The incidence of bony defects significantly increased as increasing depth of the cribriform plate. CONCLUSION: The high incidence of radiologically detectable bony defects in LLCP, as indicated in the study, may emphasize the importance of full attention by endoscopic surgeons operating on this critical area.

Radiological Measurements of the Paranasal Sinuses Using Ostiomeatal Unit CT in Children / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: As the endoscopic sinus surgery continues to gain popularity, the application of endoscopic sinus surgery has extended to children. The knowledge about the variation of the paranasal sinuses in children is essential to perform sinus operations without complication. To identify the difference of the paranasal sinuses between children and adults, we have measured the cribriform plate, the ethmoid roof (lateral lamella of the lamina cribrosa), the width of the anterior ethmoid sinus and the position of the sphenoid sinus. MATERIAL AND METHODS: Ostiomeatal unit CT scans of the paranasal sinuses obtained in consecutively imaged cases were analysed. The subjects were 58 children who were divided into two groups. One group had 22 children from ages 4 to 10 and the second group had children from ages 11 to 16. RESULTS: The length of the lateral lamella was 4.5+/-1.6 mm (group 1) and 5.4+/-2.9 mm (group 2). The depth of the lateral lamella was 4.1+/-1.4 mm (group 1) and 5.3+/-2.2 mm (group 2). The width of the cribriform plate was 2.5+/-0.9 mm for Group 1 and 2.8+/-0.9 mm for Group 2. The width of upper portion in the anterior ethmoid sinus was 7.9+/-2.1 mm for Group 1 and 9.2+/-2.9 mm for Group 2. The width of lower portion in the anterior ethmoid sinus was 9.7+/-2.2 mm for Group 1 and 13.5+/-3.1 mm for Group 2. The front of the sphenoid sinus was 45.9+/-6.6 mm from the anterior nasal spine for Group 1 and 50.9+/-7.1 mm for Group 2. CONCLUSION: Since the length and depth of the lateral lamella in children were greater than the reported lengths in the adults, it is suggested that the lateral lamella in children is more prone to danger than in adults. The distance between the anterior nasal spine and anterior face of the sphenoid sinus in children was 5 to 10 mm shorter than in the adults.