Endoscopic endonasal anatomy of superior orbital fissure and orbital apex regions: critical considerations for clinical applications

Abstract

The superior orbital fissure is a critical three-dimensional space connecting the middle cranial fossa and the orbit. From an endoscopic viewpoint, only the medial aspect has a clinical significance. It presents a critical relationship with the lateral sellar compartment, the pterygopalatine fossa and the middle cranial fossa. The connective tissue layers and neural and vascular structures of this region are described. The role of Muller's muscle is confirmed, and the utility of the maxillary and optic strut is outlined. Muller's muscle extends for the whole length of the inferior orbital fissure, passes over the maxillary strut and enters the superior orbital fissure, representing a critical surgical landmark. Dividing the tendon between the medial and inferior rectus muscle allows the identification of the main trunk of the oculomotor nerve, and a little laterally, it is usually possible to visualize the first part of the ophthalmic artery. Based on a better knowledge of anatomy, we trust that this area could be readily addressed in clinical situations requiring an extended approach in proximity of the orbital apex.

Endoscopic endonasal study of the cavernous sinus and quadrangular space: Anatomic relationships

“…The anteromedial triangle is bordered superiorly by V1, inferiorly by V2, and anteriorly by an imaginary line connecting the superior orbital fissure and foramen Rotundum representing the maxillary strut. [20][21][22][23][24] The anterolateral triangle is bordered superiorly by V2, inferiorly by V3, and anteriorly by an imaginary line connecting the foramina rotundum and ovale. Parkinson's triangle is bordered superiorly by the trochlear nerve, inferiorly by the V1, and posteriorly by a line on the tentorial edge.…”

Multiportal Combined Transorbital Transnasal Endoscopic Approach for the Management of Selected Skull Base Lesions: Preliminary Experience

“…Endoscopic endonasal dissections of the sino-orbitocranial interface (11,12) and of the pterygopalatine and infratemporal fossa via a transpterygoid approach were performed as previously described (6). Extended exposure of the middle cranial fossa floor also was achieved through an endoscopic transnasal route, reaching the same areas previously exposed through the transorbital approach.…”

Endonasal identification of the orbital apex

“…Dallan et al cite Müller's muscle as an important anatomic landmark for approaches to the orbital apex. However, they conclude that further studies and practical applications are required to assess the real potential of this landmark for endonasal surgery . In 2014, Wang et al reported transmaxillary transMüller's muscle decompression of the SOF in 10 cadaveric heads and described the clinical application of this approach in a patient with posttraumatic SOF syndrome .…”

“…The optic strut separates the SOF from the OC, whereas the maxillary strut separates the SOF from the foramen rotundum. These structures, when identifiable, may act as important intraoperative landmarks . We used the choanal arch and ethmoidal crest as anatomic references because they are constant and readily accessible structures.…”

“…The optimal surgical access route is that which provides the best possible exposure, anatomical identification, and safety. The type and location of disease influences the choice of surgical approach …”