Study of microsurgical anatomy and clinical application of the far-lateral transcondylar approach

Objective To study the microsurgical anatomy and clinical application of the far-lateral transcondylar approach and to protect the vital structure around foramen magnum. Methords Twenty formalin fixed adult cadveric heads were employed by microsurgical dissection. Ten patients with ventral and ventral-lateral foramen magnum neoplasms were operated through the far-lateral suboccipital approach between Sept. 1995 and March. 2003. Results suboccipital triangle was formed by three muscles, which was rectus capitis posterior major, superior oblique and inferior oblique. The structure in the triangle was the vertebral artery, muscular branches, vertebral venous plexus and C1 nerve. The distance of vertebral artery from lateral side of transverse foramen of atlas to its dural entry was 16.87± 2.08 ( 12.64～ 20.1) mm (L), 16.79± 1.90 ( 12.44～ 20.22) mm (R). Among the 10 patients for surgery, total removal of tumor was achieved in 4 cases, subtotal removal of tumor was achieved in 3 cases and vast partial removal of tumor was achieved in 1 case. No surgical mortality occurred in the series. Conclusion It is highly important that anatomic parameter was measured for the far-lateral transcondylar approach. The advantages of this approach include a short distance to the lesion, wide surgical exposure to the lesion, minimal retration of brain stem and main blood vessls or cranial nerves.