Telovelar Approach to Pediatric Fourth Ventricle Tumors: Feasibility and Outcome.

Abstract

To describe our institution’s experience with the telovelar approach as well as factors governing radicality and outcome for pediatric fourth ventricle tumors. During March 2015â€"January 2017, 44 children with fourth ventricular tumors were operated using the telovelar approach. Radicality, neurological outcome, complications, and survival rates were evaluated. Statistical analysis was performed to determine factors associated with radicality and neurological outcome. Gross tumor removal was achieved in 37 patients (84.1%). All patients required cerebrospinal fluid (CSF) diversion through a ventriculoperitoneal shunt. Six patients (13.6%) developed cerebellar mutism, 4 patients (9.1%) developed bulbar paralysis (lower cranial nerve palsy), and 13 patients (30.2%) had tumor recurrence. Medulloblastoma was associated with the highest risk of cerebellar mutism (p=0.040). A poor prognosis (according to overall and progression-free survival rates) was associated with subtotal resection (p=0.020), large cell/anaplastic medulloblastoma and anaplastic ependymoma (p=0.038), highrisk medulloblastoma (p=0.005), and CSF seeding (p < 0.001). The telovelar approach provides an adequate anatomical exposure of the fourth ventricle and allows early visualization and protection of its floor (brainstem). It facilitates adequate radicality and is associated with a lower incidence of cerebellar mutism and other approach-related complications. The working angle, particularly to the rostral part of the fourth ventricle, can be increased by removing the posterior arch of the atlas.