The agger nasi approach to the uncinate process: From top to bottom

Abstract

Objective: To describe a novel endoscopic approach to the Uncinate Process (UP) via the agger nasi region and evaluate its anatomical basis and clinical outcomes.

Methods: This study comprised two components. In the imaging study, 51 paranasal sinus CT scans were analyzed to measure the distance between the UP and the medial orbital wall at the agger nasi and ethmoid infundibulum regions, using standardized coronal and axial planes. In the clinical study, 53 patients with chronic rhinosinusitis underwent uncinectomy through the agger nasi approach. Pre- and postoperative SNOT-22 scores were compared after 6-months of follow-up, and complications were recorded.

Results: The distance from the UP to the orbit was significantly greater at the agger nasi region compared to the ethmoid infundibulum on both sides (p < 0.001). Clinically, the agger nasi approach allowed consistent identification of the maxillary sinus ostium and preservation of key anatomical structures. There was a significant improvement in SNOT-22 scores postoperatively (p < 0.001), with no major complications observed.

Conclusion: The agger nasi approach to the UP is a safe, reproducible, and effective technique. The greater distance from the UP to the orbit in this region may reduce the risk of orbital injury and facilitate complete identification of the natural drainage pathway of the maxillary sinus.

Keywords: Agger nasi; Endoscopic sinus surgery; Uncinate process; Uncinectomy.

Fig. 1

Computed tomography of the paranasal sinuses (bone window). Horizontal yellow lines measure the greatest distance from the uncinate process to the medial wall of the orbit at the level of the agger nasi and ethmoid infundibulum. A: coronal slice.

Fig. 2

Demonstration of uncinectomy using the agger nasi technique. Endonasal dissection of the right nasal fossa (45-degree scope view). A: middle turbinate medialization and exposure of the middle meatus. B: horizontal incision of the uncinate process.

Fig. 3

Uncinectomy using the agger nasi technique in a patient with chronic rhinosinusitis. A: computed tomography of paranasal sinuses (bone window, coronal slice). Uncinate process visible on the left side. B-F: endonasal approach to the left nasal fossa (45-degree scope view). B: exposure of the middle meatus. C: horizontal incision with shaver. C: identification of the 3 layers of the uncinate process (medial mucosa, bone, lateral mucosa). D: detachment of the uncinate process from the lacrimal bone anteriorly and inferiorly. E: identification of the natural drainage ostium of the maxillary sinus. F: final appearance of maxillary antrostomy after complete resection of the uncinate process.

Fig. 4

Distribution of measurements of distance between the uncinate process and the medial wall of the orbit at the agger nasi and ethmoid infundibulum.

Fig. 5

Distribution of pre- and 6-month postoperative SNOT-22 scores.