Microanatomy and clinical application of far lateral suboccipital transcondylar approach

Objective To supply the microsurgical anatomy for far lateral suboccipital transcondylar approach.Methods Sixteen adult cadaver heads and fifteen dry skulls were used for microsurgical dissection and observation.Results Mastoid processs tip,transverse processs of atlas,ventral ramus of C2,occipital condyle,and inferior occipital triangle all were important signs.Abundant venous plexuss around the third segments of vertebral artery was the important bleeding source during operation.Resection of one third of posterior middle occipital condyle could extend the angle of surgery by(15±1)°;resection of one second could extend the angle of surgery by(18±1)°.The result was applied clinically in 5 patients with tumors of ventral portion of magnum foramen.The postoperative effect was good.Conclusion Despite of the complex anatomy,the far lateral suboccipital transcondylar approach can provide sufficient exposure of the anterior and lateral aspects of the foramen magnum region without retracting the brainstem.Only one second of the posterior middle occipital condyle needs to be removed.