Medial and Superior Orbital Decompression: Improving Access for Endonasal Endoscopic Frontal Sinus Surgery
Abstract
Objective: Visualization by Draf I-III endoscopic access to the frontal sinus via drainage pathways is sometimes inadequate. We compare lateral frontal sinus exposures by Draf approaches versus our modification of removing the medial-superior wall of the orbit while preserving the periorbita.
Methods: Twenty cadaveric heads dissected using Draf IIB, III, and modified Draf III with medial and superior orbital decompression (MSOD) underwent thin-cut computed tomography (CT) scanning. Under image guidance, measurements extended from the midline crista gali to the most lateral point of the frontal sinus.
A case report shows the modified Draf III improved frontal sinus access. Results: Comparing Draf IIB and III with Draf III with MSOD, respectively, distances between midline and most lateral point averaged 19.1 mm, 23.7 mm, and 30.4 mm (left) and 18.7 mm, 25.1 mm, and 32.2 mm (right).
Differences between Draf III with/without MSOD were 6.65 mm (left) and 7.09 mm (right); 12 heads were excluded because of under-pneumatization of the sinuses. Conclusions: Draf III with MSOD extended surgical access to lateral regions of the frontal sinus.
This extension achieved better visualization and instrumentation with minimal removal of the frontal bone's orbital segment anterior and superior to the anterior ethmoidal artery while preserving the periorbita.