Intraoperative medialization of medial rectus muscle as a new endoscopic technique for approaching intraconal lesions

Intraconal tumors of the orbit are rare entities and surgical treatment is challenging. Endoscopic transnasal approaches to the orbit offer a new perspective for surgery, although only few reports exist in literature. This study displays the Graz experience with endoscopic approaches to intraorbital tumors between 2006 and 2010 introducing a novel endoscopic technique for temporary medialization of the medial rectus muscle facilitating access to the orbital cone.

A retrospective analysis of patients' charts was performed.

For approaches to intraconal lesions a special endoscopic temporary medialization technique of the medial rectus muscle through applying transseptal sutures was developed. Six patients (four male and two female patients) have been included in this study presenting with intraconal/intraorbital tumors. Three patients underwent endoscopic surgery for two hemangiomas and one Schwannoma, respectively, and three patients were successfully biopsied endoscopically revealing one malignant melanoma, one malignant lymphoma, and one optic glioma each. Both hemangiomas were completely resected without any deterioration of vision. The Schwannoma was partially resected with postoperative imaging showing no tumor progression within 3 months. No intraoperative complications occurred. Five cases were performed with computer assisted surgery using CT/MR fusion navigation.

Although technically challenging, the endoscopic approach to the orbit, even for intraconal lesions with medialization of the medial rectus muscle, can be safe and promising for well-selected cases. Good postoperative results and sufficient material acquisition for proper histological examination can be obtained. Advantages are good visualization of the surgical field and avoidance of external scars. Limitations to endoscopic techniques are tumors in the lateral superior and lateral inferior quadrant of the orbit.