Anatomo-topographic landmarks on the lateral wall of nasal cavity used in endonasal surgery.

INTRODUCTION: A dissection of the lateral wall of nasal cavity that imitates a true endonasal operation was the design of the present study. The object of the study was by measuring the distance between a pivot landmark and important anatomical structures revealed successively during an endonasal operation to create additional highlights that will minimise the hazard of injuring vital structures. METHODS: Twenty anatomical preparations of sagittally sectioned heads from cadavers (elderly males of Bulgarian origin) were dissected to study the topographic relationships between the great paranasal cavities (maxillary, frontal, and sphenoidal sinus) and the ethmoidal labyrinth. Using punctum subnasale as a pivot landmark, the distances to crucial microendoscopic landmarks (i.e., nasolacrimal duct, uncinate process, ethmoidal bulla, base of the skull, anterior wall of the sphenoid sinus, orifice of the maxillary sinus) were measured at different angles to the horizontal plane. RESULTS: The mean distances from punctum subnasale to the natural ostium of the maxillary sinus and anterior wall of the sphenoidal sinus, measured at an angle of 30 degrees to the floor of the nasal cavity, were 48.25 +/- 0.75 and 67.105 +/- 0.794 mm, respectively. At an angle of 45 degrees, the mean distance to the nasolacrimal duct was 38.056 +/- 0.591 mm; to the uncinate process 45.25 +/- 0.57 mm; to the ethmoidal bulla 50.25 +/- 0.57 mm; and to the base of the skull 66.053 +/- 0.818 mm. Mean distance of 43.158 +/- 0.568 mm to the lacrimal sac and 60.25 +/- 0.68 mm to the base of the skull were measured at an angle of 60 degrees. CONCLUSION: The analysis of the results imply that the selected distances will contribute to a more precise application of this contemporary surgical method.