Complications following preresection shunting in patients with posterior fossa tumors.

Abstract

In their paper “Infratentorial complications following preresection CSF diversion in children with posterior fossa tumors,” Dr. El-Gaidi and colleagues provide us with a retrospective review of their experience utilizing preoperative shunting for CSF diversion in patients with posterior fossa tumors presenting with symptomatic hydrocephalus.3 Of 301 patients who underwent CSF diversion days prior to tumor resection, 5 patients had evidence of intratumoral hemorrhage (ITH) and 2 had upward transtentorial herniation (UTH) precipitating a decline in their neurological examination. These investigators conclude that infratentorial complications following CSF diversion before resection are rare, but that the prognosis for these patients is quite poor. While the authors state that there is no consensus on preoperative management of hydrocephalus in children with posterior fossa tumors, recent publications have advocated for early tumor removal without preresection CSF diversion, given the low requirement for permanent CSF shunt placement in these children.1,6,9 The rate of permanent CSF diversion in current studies ranges from 5% to 36%.1,2,5,6,9–11 Avoidance of shunts is advocated by most surgeons due to risk of failure, risk of infection, and the complications presented here in this paper. Thus, current state-of-the-art therapy is to avoid placing preresection shunts, reserving placement of an external ventricular drain for situations in which glucocorticosteroids are not effective in relieving symptoms or for emergency situations. In this article, the rationale used for immediate CSF diversion in those with hydrocephalus is the lack of operating room (OR) availability and resources, the concern for infection with external ventricular drains, and the positive effect of decreased pseudomeningoceles and CSF leaks postoperatively.3 Interestingly, almost half of the patients in this paper had shunts inserted in the OR on the day of presentation or the following day. One wonders if time could have been made for early resection, given that time for placement of a shunt was available. In regards to infection with the use of with external ventricular drains, the authors concerns here are warranted.13,14 Infection rates with external ventricular drains have been shown to increase after 5 days of drainage.8 It appears plausible that, if OR time is difficult to obtain, an external ventricular drain could be utilized for those children with moderate to severe hydrocephalus preoperatively while waiting for an open OR time slot. It is unclear if antibiotic-impregnated catheters are available at the authors’ institution, as these catheters have been shown to decrease infection rates significantly.14 While a decrease in pseudomeningoceles and CSF leaks may be true, the possible CSF leak repair appears far more manageable than the ITH or UTH they note here. Preoperative endoscopic third ventriculostomy (ETV) was also performed in 28.9% of the patients included in this study. The routine use of preoperative ETV has been debated for children with posterior fossa tumors. However, the conclusion is essentially the same as that for shunt placement: given the low need for permanent CSF diversion and the risks associated with ETV, the potential benefit does not justify routine preoperative ETV for these patients.4,6,9 Intratumoral hemorrhage and UTH are known com-