Anatomical study of extreme lateral suboccipical approach

Objective: To provide microsurgical anatomy for the extereme lateral suboccipital approach. Methods: Ten adult cadaveric heads were used for microsurgical dissection and observation. Results: The suboccipital triangle was an important landmark in this approach. After dissection and mobilization of vertebral artery, partial resection of posterior one third of occipital condyle was completed and hypoglossal cannal was identified. Drilling of occipital condyle could significantly increase the exposure of anterior foramen magunum region, and further drilling of jugular tubercle played an important role in exposure of middle and inferior portion of clivus. Attention should be paid to the complex relationship between vertebral artery, its branches and the posterior cranial nerves. Conclusion: Despite the complex anatomy, the extreme lateral suboccipital approach can provide sufficient exposure of the anterior and lateral aspects of the cervicomedullary junction without the need to retract the brain stem. Only the posterior one third of the occipital condyle need to be removed to achieve the appropriate exposure.