The extended transbasal approach: a quantitative anatomical and histological study

Area of Science:

• Neurosurgery
• Anatomy
• Surgical Techniques

Background:

• The transbasal approach, developed in 1972, has seen modifications for anterior fossa and sphenoethmoidal region access.
• The extended transbasal approach with olfactory preservation offers improved exposure and wider anatomical access.

Purpose of the Study:

• To anatomically demonstrate and quantify the exposure provided by the extended transbasal approach.
• To compare exposure levels with standard subfrontal and transbasal approaches.
• To histologically investigate olfactory nerve extension into the nasal mucosa.

Main Methods:

• Anatomical study using photographic demonstration and quantification of surgical exposure.
• Comparison of exposure areas using standard subfrontal, transbasal, and extended transbasal approaches with pituitary stalk as target.
• Histological examination of olfactory nerve penetration into the nasal mucosa.

Main Results:

• The extended transbasal approach more than quadrupled the 'external window of exposure' to the pituitary stalk.
• This approach significantly enhances visualization of the medial orbit, cavernous sinus, clivus, and vertebrobasilar complex.
• Olfactory nerves were found to extend only 10 mm below the cribriform plate.

Conclusions:

• The extended transbasal approach with olfactory preservation offers a substantial increase in surgical exposure compared to other methods.
• This technique provides access to a wider range of critical anatomical structures.
• The limited extension of olfactory nerves supports the safety of this approach for preserving olfaction.