Anteriorly Tilted Coronal CT of Paranasal Sinuses for Endoscopic Sinus Surgery

Anteriorly Tilted Coronal CT of Paranasal Sinuses for Endoscopic Sinus Surgery

Kazuhiro Nomura,¹ Tomotaka Hemmi,¹ Mitsuru Sugawara¹ and Ryoukichi Ikeda²

¹Department of Otolaryngology, Tohoku Kosai Hospital, Sendai, Miyagi, Japan
²Department of Otolaryngology-Head and Neck Surgery, Iwate Medical University School of Medicine, Shiwa-gun, Iwate, Japan

Conventional coronal CT scans of paranasal sinuses, aligned perpendicularly to the nasal floor, often deviate significantly from the endoscopic view during sinus surgery. This discrepancy complicates the interpretation of anatomical structures. In response, we propose the utilization of anteriorly tilted coronal CT slices to enhance anatomical understanding. These slices align more closely with the endoscopic view, fostering an intuitive grasp of paranasal sinus anatomy. This study aims to quantify the tilt of the endoscope to the nasal floor during endoscopic sinus surgery. To figure out the tilt of the endoscopically true coronal slices, we calculated the tilt of the endoscope to the nasal floor in the operative setting by taking pictures of the operation and measuring the image and sagittal CT. Fourteen patients (25 sides of paranasal sinuses) were analyzed. Endoscope tilts to the nasal floor were measured at different anatomical landmarks: 16.2 ± 9.7 degrees (lower edge of ground lamella), 29.8 ± 7.9 degrees (central ground lamella), 62.3 ± 10.1 degrees (most superior part), and 25.6 ± 7.0 degrees (optic canal). In conclusion, we showed the actual tilt of the endoscope to the nasal floor during endoscopic sinus surgery. A 30-degree anteriorly tilted coronal scan for frontal recess and sphenoid sinus is more intuitive than a traditional coronal scan, which helps surgeons understand the complex sinus anatomy.

Key words —— endoscopic sinus surgery; frontal recess; frontal sinus; sphenoid sinus; surgery

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Tohoku J. Exp. Med., 2024 June, 263(2), 115-121.

Correspondence: Kazuhiro Nomura, M.D., Ph.D., Department of Otolaryngology, Tohoku Kosai Hospital, 2-3-11 Kokubun-cho, Aoba-ku, Sendai, Miyagi 980-0803, Japan.

E-mail: nomura@orl.med.tohoku.ac.jp