Microsurgical management of fourth ventricle astrocytoma via the median suboccipital keyhole approach: A review of 12 cases.

OBJECTIVE: To investigate the clinical effect and surgical techniques of fourth ventricle astrocytoma resection through the median suboccipital keyhole approach.

METHODS: Twelve patients received tumor resection through the median suboccipital keyhole approach in our department. A 4-cm median suboccipital excision starting 1 cm under the foramen magnum region and directed vertically upward was applied. The fourth ventricle was exposed through a cerebellomedullary fissure approach within a bone hole approximately 2.5 cm in diameter. All clinical data (including pre-/post-operative symptoms, magnetic resonance imaging scan, intra-operative findings, tumor resection rate, and surgical complications) were collected and analyzed.

RESULTS: In our treatment group, the mean maximum tumor diameter was 3.48±1.3 cm, and the mean tumor volume was 34.79±20.70 cm3 . The complete resection rate was 92%. The average operative blood loss was 127.0±24.6 mL; the mean craniotomy time was 26.4±6.0 minutes; the mean tumor resection time was 190.3±31.2 minutes; the mean cranial closure time was 42.3±6.1 minutes; and the average hospitalization time was 13.6 ±2.4 days. The mean Glasgow Outcome Scale (GOS) score before discharge was 4.92.

CONCLUSIONS: If appropriate micro-neurosurgical techniques are used via the median suboccipital keyhole approach, the fourth ventricle astrocytoma may be accessed and resected safely with shorter surgery time, reduced hemorrhage during operation, low incidence of postoperative complications, good recovery, and shorter hospitalization time.