Endoscopic verification of the sphenoid sinus

Area of Science:

• Otolaryngology
• Surgical Anatomy
• Medical Imaging

Background:

• Differentiating posterior ethmoid and sphenoid sinuses during endoscopic sinus surgery is often difficult.
• Accurate anatomical identification is crucial for surgical success, regardless of image guidance.
• The study investigates the utility of visualizing the sphenoid floor with a 0-degree endoscope as an anatomical landmark.

Purpose of the Study:

• To verify the reliability of the inability to see the sphenoid floor with a 0-degree nasal endoscope as an anatomical landmark in endoscopic sinus surgery.
• To assess the angles formed by the endoscope and sphenoid floor in relation to endoscope angles of view.

Main Methods:

• Radiological measurements of the angle between a 0-degree endoscope at the sphenoid ostium and the sphenoid floor mucosa were taken in 93 sinuses.
• Angles of view for three common nasal endoscopes were directly measured.
• Radiological measurements were compared to the measured endoscope angles of view.

Main Results:

• The average angle to the most inferior aerated portion of the sphenoid sinus was 113.6 degrees (range: 77–145 degrees).
• The angles of view for the tested endoscopes were 38.1, 46.7, and 44.4 degrees.
• None of the tested endoscopes could visualize the most inferior aerated portion of 100% of the assessed sinuses.

Conclusions:

• The inability to visualize the sphenoid floor mucosa with a 0-degree nasal endoscope is a dependable surgical finding.
• Preoperative imaging should identify variations like hypoplasia or severe mucosal edema that could affect this landmark.
• In the absence of such variations, this inability serves as a reliable clue for sphenoid sinus positioning during surgery.