Comparing Endoscopic Measurements of the Anterior and Posterior Ethmoidal Arteries with CT Measurements: A Cadaveric Study.

OBJECTIVE: To reveal the reliability of radiological measurements of the ethmoid arteries. METHOD: Five fresh frozen cadaveric heads underwent computed tomography and endoscopic sinus surgery. The lateromedial length of the anterior ethmoidal artery (AEA) and its distance to the axilla of the middle turbinate (MTA), the sphenoethmoidal recess (SR) and the posterior ethmoidal artery were measured. The posterior ethmoidal artery (PEA) was referenced to the SR. These anatomical parameters were measured both radiologically and endoscopically, and the compatibility of the two was examined. RESULTS: Ten nasal cavities were dissected. We found that the distance of MTA to the AEA was 16±8 mm in dissection, 21±4 mm radiologically in the sagittal section, the distance of SR to the AEA was 14±3 mm in dissection, 19±4 mm radiologically in the sagittal section, and the distance of the AEA to the PEA was 10±3 mm in dissection, 12±3 mm radiologically in the axial section. The distance of the PEA to SR was 6±3 mm in dissection, 8±2 mm radiologically in the sagittal section. CONCLUSIONS: The distance of the AEA to the MTA, the distance of the AEA to the PEA and the distance of the PEA to the SR were compatible with each other in the dissection and in the radiologically evaluation, whereas the distance of the AEA to the SR was not compatible.

Endoscopic Anatomy of the Lacrimal Sac: A Cadaveric Study.

OBJECTIVE: To describe the anatomy of the lacrimal sac in relation to the lateral nasal wall by cadaver dissection, and to measure the distances of surgically important landmarks from relevant structures for safer and more efficient surgery. METHOD: A total of 12 endoscopic dacryocystorhinostomy (DCR) were performed on both sides (right and left) of 6 fresh-frozen cadavers. The distances of the lacrimal sac to the posterior edge of the uncinate process, the frontal process of the maxilla, the maxillary ostium, the nasal vestibule, the middle turbinate attachment and the inferior turbinate were measured. In addition, the width and length of the lacrimal sac were measured. RESULTS: The mean width and length of the lacrimal sac were 5.6 mm and 11.1 mm, respectively. The lacrimal sac was located at 15.2 mm from the posterior edge of the uncinate process, at 35.5 mm from the nasal vestibule, at 13.5 mm from the maxillary ostium, at 12.2 mm from the frontal process of the maxilla, at 8.7 mm from the middle turbinate attachment, and at 7.3 mm from the inferior turbinate. CONCLUSION: This study provides additional measurements regarding the lacrimal sac and its relationships with nearby landmarks for use in endoscopic dacryocystorhinostomy. The distances of the lacrimal sac to the nasal vestibule, the uncinate process and the frontal process of the maxilla are not as reliable as the middle turbinate attachment for predicting the anatomic localization of the lacrimal sac during DCR.