External Ethmoidectomy

Introduction

In many countries, external ethmoidectomy is rarely performed due to the widespread adoption of endoscopic techniques. However, in some clinics where endoscopic equipment is not available, the external ethmoidectomy approach is still an important technique used in the management of ethmoid disease. It also still has value for the management of sinonasal tumors, epistaxis, orbital infection, and trauma in special circumstances. It may be used in combination with other approaches (transnasal and transcranial) to provide additional exposure. An open approach may be preferred for some highly vascular tumors.

Key Operative Learning Points

• The incision should be placed at the junction of aesthetic units, midway between the nasal dorsum and medial canthus.

• The frontoethmoidal suture line defines the level of the skull base (roof of the ethmoid sinus).

• The anterior and posterior ethmoidal arteries are at the level of the frontoethmoidal suture line. Injury to these arteries can result in a retrobulbar hematoma.

• The posterior lacrimal crest is the anterior limit of the ethmoid sinus and defines the lacrimal fossa. Avoidance of trauma to the nasolacrimal duct will avoid postoperative epiphora.

• The cribriform plate is medial to the middle turbinate and may be at a lower level than the frontoethmoidal suture line. Violation of the lateral lamella can result in a cerebrospinal fluid (CSF) leak.

• The optic nerve is in close proximity to the posterior ethmoidal artery.

Preoperative Period