Microsurgical Anatomy of Transcondylar, Supracondylar, and Paracondylar Extensions of The Far-Lateral Approach

Introduction The far lateral approach is an inferolateral extension of the lateral suboccipital approach. Over the years, it has become a workhorse for ventral foramen magnum (FM) meningiomas and other intradural lesions located anterior to the dentate ligament. Key technical aspects of the lateral approach and transcondylar, supracondylar, and paracondylar extensions are reviewed. Method Five dry skulls and 5 formalin-fixed adult heads were used. A transcondylar, supracondylar, and paracondylar far lateral approach was performed to examine the area primarily exposed by each variant. Result The far lateral approach is an infero-lateral extension of the lateral sub-occipital approach. It allows for a direct access to the area between the midline and the dentate ligament. Far lateral transcondylar variant is directed through the occipital condyle and offers an unobstructed view of the lower clivus and pre-medullary area. Far lateral transcondylar exposure provides a more direct and tangential access to the midline resulting of great advantage in the treatment of those meningiomas considered as anterior. Supracondylar [(transjugular tubercle (JT)] approach is directed through the (supra)condylar fossa and JT. It involves an extradural drilling of the JT but not the occipital or lateral condyle. It offers a direct and unobstructed access to the midline lower clivus and FM but a level slightly more cranial than the far lateral transcondylar variant. Paracondylar exposure is conducted through the posterior aspect of the jugular process of the occipital bone and offers a tailored access to the posterior aspect of the jugular foramen. Conclusion A perfect knowledge of the anatomy of the postero-lateral skull base and the FM is essential to safely perform the far-lateral approach and to take advantage of its transcondylar, supracondylar and paracondylar variations according to the different lesions to be treated.