TRANSNASAL ENDOSCOPIC APPROACH TO EXPOSE THE MEDIAL RECTUS FROM THE ANNULUS OF ZINN TO THE PENETRATION OF TENONS CAPSULE

Conventional strabismus surgery employs a conjunctival incision to gai n access to Tenon's space where a wide variety of procedures are routi nely performed on the tendon and anterior aspect of the extraocular mu scles. Recently, transnasal endoscopic surgical techniques have gained acceptance as effective means of decompressing the medial wall and fl oor of the orbit in patients with thyroid-related orbitopathy. The orb ital surface of the medial rectus and inferior rectus are exposed from the annulus of Zinn to a position close to where the muscles penetrat e Tenon's capsule. In theory, this technique also provides the exposur e necessary to locate and retrieve a ''lost'' medial rectus when the u sual subTenon's approach fails to recover the muscle. Cadaver studies demonstrate the feasibility of exposure and suture placement in the st ump of a lost medial rectus with passage of the suture through Tenon's capsule to transmit the force of the muscle to the globe, provided th at the lost muscle is retrieved before severe contracture develops.