The Agger Nasi cell and uncinate process, the keys to proper access to the nasolacrimal drainage system.

BACKGROUND

Profound knowledge of the surgical anatomy is required to perform any dacryo-cysto-rhinostomy (DCR) procedure. In endoscopic endonasal DCR surgery, the uncinate process (UP) and/or agger nasi (AN) cell are frequently found to obstruct access to the lacrimal fossa. The aim of this study was to analyse the radiological anatomy of the UP and the AN cell in relation to the lacrimal sac.

METHODS

Preoperative computed tomography (CT) scans of patients undergoing DCR and other endoscopic sinus surgeries were analysed regarding their anatomical variations concerning the UP and the AN cell at the level of the common canaliculus. The covering of the lacrimal fossa by the UP was graded and a surgically relevant AN cell was sought after.

RESULTS

CT datasets of 60 sides were included. Analysis showed an AN cell overlying the upper parts of the lacrimal sac in 55% of patients. An anteriorly attaching UP covering at least 50% of the lacrimal fossa was found in 63% of individuals.

CONCLUSION

In this study more than 80% of all patients presented with either a very anteriorly attached UP or an AN cell that would have to be removed to perform effective endoscopic DCR. The AN cell and the UP need to be included in the endonasal surgical concept.