“Round the Clock” Surgical Access to the Orbit

Introduction: Surgical approaches to orbital lesions represent challenging procedures that often require the combined effort of different specialists. To minimize the risk of injuring important neural and vascular structures in this area, surgical approaches must be available to provide 360 degrees of access to the orbit. Endoscopic endonasal approaches complement the traditional microsurgical approaches for biopsy or resection and offer the potential to reduce morbidity.

Methods: A review of 12 selected patients operated on at our institution over the last 3 years was performed, recording clinical presentation, pathology, and location in relation to the extraocular muscles. In addition, preoperative coronal MRI and/or CT views were compared using a “clock model” of the orbit with its center at the optic nerve. The rationale for choosing an external, endoscopic, or combined approach is discussed for each case.

Results: Five patients underwent an endoscopic endonasal transorbital approach, with two of them also requiring a medial transconjunctival approach; five patients were treated through an external approach; and two patients required a combined endoscopic and external approach. The pathologies treated included two cavernous hemangiomas, two foreign bodies, two melanomas, one angioleiomyoma, one orbital osteoma, one metastasis, one pleomorphic adenoma of the lacrimal gland, one inflammatory lesion, and one neuroendocrine tumor. Using the right orbit for demonstration of the clock model, the medial transconjunctival approach provides access to the anterior orbit from 1 to 6 o'clock; endoscopic endonasal approaches provide access to the mid- and posterior orbit and orbital apex from 1 to 7 o'clock. The lateral micro-orbitotomy gives access to the orbit from 8 to 10 o'clock. The frontotemporal craniotomy with orbital osteotomy accesses the orbit from 9 to 1 o'clock; addition of a zygomatic osteotomy to this extends access from 6 to 8 o'clock.

Conclusions: Combined, the above approaches provide 360 degrees of access to the entire orbit with the choice of the optimal approach guided primarily by the avoidance of crossing the plane of the optic nerve.