Objective: To explore the surgical outcome and skills of keyhole approaches to posterior cranial fossa tumors.
Methods: A retrospective analysis of the clinical data of 43 consecutive patients with posterior cranial fossa tumors, including acoustic neurinoma, petroclival meningioma, pons tumor, fourth ventricular tumor, etc. was conducted. Subtemporal, retromastoid, or middle suboccipital keyhole approach was chosen respectively according to the anatomic positions of those different tumors. The length of the incision was about 4 cm, and the diameter of bone window was 2.0 - 2.5 cm. Normally dura was sutured tightly and no catheter was placed in the surgical fields.
Results: The tumors were totally removed in 37 of the 43 patients (86.0%), subtotally removed in 5 (11.6%) and mostly removed in 1 (2.3%). There were no complications obviously related to the limited exposure resulting from keyhole approaches. All of the 18 acoustic neurinomas (100%) were totally removed and the facial nerves of 15 patients (83.3%) were preserved anatomically, however, one patient died of brain stem edema on the 2nd postoperative day. Out of the 8 petroclival meningiomas, 5 (62.5%) were resected totally, 2 (25%) subtotally, and 1 (12.5%) grossly. Postoperatively, 2 patients still remained slight hemiparesis, and 1 presented with mild facial paralysis. Among the 6 pons tumors 3 were removed totally and 3 subtotally. There were no postoperative neurological deficits. All the other tumors were resected completely without neurological dysfunction observed, however, one patient with a cholesteatoma failed to demonstrate apparent improvement in his diplopia.
Conclusion: Microsurgical treatment of posterior cranial fossa tumors via keyhole approaches, with safe, succinct and minimally invasive property, is one of the promising directions in modern neurosurgery.