A neuroendoscopic approach to the aqueduct via the fourth ventricle combined with suboccipital craniectomy

Objectives: We have tried to approach the aqueduct less invasively with the endoscope in combination with a small suboccipital craniectomy, especially for lesions of the aqueduct close to the fourth ventricle. Methods: The patient is placed in the prone position and a small suboccipital craniectomy is performed. After elevating the bilateral tonsils with retractors, the sheath of the endoscope is inserted from a small skin incision made on the posterior midline of the neck, far from the craniectomy site. The skin incision for endoscopic insertion is planned on the linear extension connecting the aqueduct and the foramen of Magendi on the craniocervical MRI. A rigid endoscope is inserted through the fourth ventricle to the aqueduct for exploration and surgical manipulation. Results: Two cases with hydrocephalus due to aqueductal stenosis, with gait disturbance were operated. After exploration of the aqueduct via the fourth ventricle, endoscopic aqueductal plasty was performed. The postoperative courses were uneventful. The patients' symptoms disappeared. Conclusions: This approach can be applied for less invasive endoscopic exploration and surgery around the aqueduct close to the fourth ventricle with a rigid endoscope, without overflexion of the neck, or a large craniectomy, or overretraction of the tonsils, or incision of the inferior vermis.