Abstract
Background We evaluated a transrectus capitis posterior muscle triangle approach to the posterolateral
foramen magnum, occipital condyles, jugular tubercle, and the fourth ventricle. We
also assessed factors that affect the amount of bone removal required.
Objective To evaluate if the proposed approach is as effective as standard open approaches
to expose the lateral portion of the foramen magnum.
Methods The proposed minimally invasive fully endoscopic approach was performed in 15 cadaveric
specimens using 4-mm (0- and 45-degree) endoscopes.
Results Using a 5-cm straight paramedian incision, the rectus capitis posterior minor and
major muscles were partially removed unilaterally, providing a corridor through the
muscles to reach the foramen magnum region. After meticulous soft tissue dissection,
key anatomical landmarks can be identified such as the greater occipital nerve, the
vertebral artery that wraps around the atlanto-occipital joint, and the bony protuberance
that heralds the occipital condyle. A suboccipital craniotomy associated with the
transcondylar, supracondylar or paracondylar approach is performed depending on the
amount of bone removal desired to maximize the surgical view. By doing so, the jugular
foramen can be exposed laterally as well as the fourth ventricle medially.
Conclusion The proposed endoscopic approach can provide access through the transrectus capitis
posterior muscle triangle leading directly to the occipital condyle. A stepwise approach
is critical to gain a surgical corridor to the inferolateral petroclival region and
the fourth ventricle.
Keywords
posterolateral condyle - jugular tubercle - minimally invasive - transrectus capitis
posterior muscle triangle - fully endoscopic
