Lateral basal approach for V3 exposure in the supine position

Background: Exposure of the third segment of the vertebral artery (V3) is occasionally required during posterior fossa surgery to obtain proximal vascular control. Most reported techniques were developed for the lateral or park-bench position and rely primarily on muscular dissection together with complex osseous landmarks. Although the lateral basal approach (LBA), an anatomy-based technique utilizing the deep cervical fascia, has previously been described for the posterolateral craniovertebral junction, its application for V3 exposure in the supine position has not been reported. Methods: We describe a practical application of the previously reported LBA for exposing the V3 segment during posterior fossa surgery performed in the supine position. Sequential development of the lateral basal space through the interlaminar fatty tissue provides a reproducible anatomical corridor to the superior oblique muscle and the C1 transverse process, beneath which the V3 segment is consistently identified. Results: The described anatomical sequence enabled reproducible identification of the V3 segment during posterior fossa surgery in the supine position without additional skin incision, extensive muscle dissection, or patient repositioning. Conclusion: This report illustrates a practical application of the previously described LBA rather than a novel approach to the vertebral artery. Recognition of the anatomical sequence from the interlaminar fatty tissue to the superior oblique muscle and C1 transverse process enables straightforward V3 exposure without altering the operative position and may facilitate proximal vertebral artery control when required during supine posterior fossa surgery.