Simultaneous Endoscopic Endonasal Decompression of the Optic Canal, Superior Orbital Fissure, and Proper Orbital Apex for Traumatic Orbital Apex Syndrome: Surgical Anatomy and Technical Note

Abstract

ObjectivesTraumatic orbital apex syndrome (TOAS) is an uncommon but severe ocular complication of craniomaxillofacial fracture. The optimal surgical strategy for TOAS has not been determined. To investigate the endoscopic anatomy of the orbital apex region, propose a protocol for simultaneous endoscopic endonasal decompression of the optic canal, superior orbital fissure, and proper orbital apex (EEDCFA) for TOAS and report its use in two patients.MethodsAn endoscopic endonasal approach was utilized to dissect the orbital apex region in two silicon-injected adult cadaveric heads. The details of the procedure used for decompression of the orbital apex were determined. The effects of this procedure were determined in two patients with TOAS who underwent simultaneous decompression of the optic canal, superior orbital fissure, and proper orbital apex.ResultsThe orbital apex consisted of three portions, the contents of the optic canal superomedially; the contents of the superior orbital fissure inferolaterally; and the converging portion, or proper orbital apex, anteriorly. From an endoscopic endonasal approach, the optic nerve, superior orbital fissure, and orbital apex convergence prominences were found to form a π-shaped configuration. This π-shaped configuration was indicative of the orbital apex and was an important landmark for decompression of the orbital apex. Endonasal decompression of the orbital apex in the two patients resulted in the satisfactory recovery of extraocular mobility, with no surgical complications.ConclusionsEEDCFA is feasible, effective, and safe for patients with TOAS caused by direct compression of displaced fracture segments. The π-shaped configuration is a valuable landmark for EEDCFA.

Traumatic oculomotor nerve palsy treated with transnasal endoscopic decompression through the optic strut

“…Muller's muscle is considered a marker for identifying the optic strut, the maxillary strut and the superior orbital fissure, but it is rarely used clinically (24,25). Liu et al described a "π" structure for the identification of the optic canal, the superior orbital fissure and the orbital apex (10). Alfieri et al explained in detail the composition of the "optic strut triangle" under the transnasal endoscope, which is essential in clinical work and this study.…”

“…It is, therefore, plausible to suggest that optic strut drilling is necessary to achieve a satisfactory decompression of the oculomotor nerve fissure segment. At present, decompression surgeries of the superior orbital fissure, orbital apex and optic canal are also performed in some cases of traumatic oculomotor nerve palsy, achieving good results (10,29), but none of them involve optic strut drilling. It was found that 270°decompression could be achieved after the optic strut was ground (Figure 1A), and the medial margin of the oculomotor nerve fissure segment could be sufficiently decompressed after the orbital apex and superior orbital fissure were ground in turn.…”

“…Furthermore, 4 patients with internal ophthalmoplegia also recovered at the same time. Liu et al applied a combined decompression of the optic canal, superior orbital fissure and orbital apex with a transnasal endoscope in patients with superior orbital fissure syndrome (SOFS) with success (10). Up to now, transnasal endoscopic decompression in patients with traumatic oculomotor nerve palsy has been rarely reported.…”