[Transcranial approach to the orbit: a microanatomical study].

OBJECTIVE: To provide detailed knowledge of microanatomy and parameters for transcranial approach to the orbit. METHOD: Three intraorbital approaches were studied by dissecting and measuring 20 adult cadaveric heads under x5 to 25 magnification. RESULTS: The medical approach was directed through the space between the superior oblique and the levator palpebrae superior muscles, which was selected for lesions located in the medial part of the orbital apex. The central approch was directed through the space between the levator palpebrae superior and the superior rectus muscles. There were two variants of the central approach, the choice of which depends on whether the frontal nerve was retracted medially or laterally. The approach was selected for lesions located in the midportion of the intraorbital segment of the optic nerve. The lateral approach was directed through the space between the superior and the lateral rectus muscle. There were two variants of the lateral approach, the choice of which was determined by whether the superior ophthalmic vein is retracted medially or laterally. This approach was selected for lesions located in the superior, inferior or lateral part of the orbital apex as well as the superior orbital fissure. CONCLUSION: This research provides a microanatomical foundation for avioding the important nerves and vessels damage in transcranial to orbital surgery.