Hydrocephalus in Pediatric Patients with Posterior Fossa Tumors

Predictor

Score

Age <2 years

Presence of papilledema (later replaced with transependymal edema)

Moderate/severe hydrocephalus

Cerebral metastases

Preop estimated tumor diagnosis

Medulloblastoma

Ependymoma

Dorsally exophytic brainstem glioma

Total possible

Table 12.2

The CPPRH’s predicted probabilities of postresection hydrocephalus at 6 months

CPPRH score	Probability of hydrocephalus at 6 months after resection
0	0.071
1	0.118
2	0.191
3	0.293
4	0.422
5	0.562
6	0.693
7	0.799
8	0.875
9	0.925
10	0.956

The efficacy and safety of ETV as a preoperative treatment of posterior fossa tumor-associated hydrocephalus is supported by literature and clinical practice; its use as a postresection treatment for persistent hydrocephalus is also mentioned in the literature. Even the combined use of perioperative ETV with ICP monitoring and postresection EVD in cases with persistent ventricular dilatation and persistently abnormal high ICP values and even VP shunt implementation in failed ETV cases are studied. The only factor associated with a higher rate of persistence of postoperative hydrocephalus was found to be the severity of the ventricular dilation at diagnosis, and 93.3 % of children with persisting hydrocephalus had severe preoperative ventricular dilatation (Figs. 12.1, 12.2, 12.3, and 12.4). In 90 % of those cases ETV was successful [25]. In selected cases it makes biopsy possible too (Table 12.3).

Fig. 12.1

The brainstem is pushed anteriorly toward the clivus (a) and also upward by a nodular-type medulloblastoma (b). The posterior part of the third ventricle is elevated. A preoperative ETV was performed

Fig. 12.2

A vermian tumor (pilocytic astrocytoma) (a) is presented with ventricular dilatation (b) and periventricular edema (c). Early postoperative study (d–f) demonstrates opening of the IV ventricle and resolving periventricular edema

Fig. 12.3

A huge pilocytic astrocytoma case was admitted to the hospital in a precomatous condition at night (a, b). An EVD was inserted immediately and the patient was operated the next morning. Three months after the surgery, the ventricles are still dilated without high pressure (c, d). There is no need for CSF diversion surgery

Fig. 12.4

An ependymoma case of posterior fossa with three different lesions (left PCA angle (a–b), prepontine cistern and tenurial incisor (c)). The IV ventricle is open (a). All three lesions were removed in the same session, but hydrocephalus did not resolve. Because of multiple septations and adhesions at the interpeduncular and prepontine cistern, a VP shunt was inserted

Table 12.3

ETV procedures performed after removal of a posterior fossa tumor: review of the literature

Series reported in literature	Period of study (years)	Total no. of patients operated on for a posterior cranial fossa tumor with associated hydrocephalus	Total no. of patients with persisting hydrocephalus	No. of patients treated by postoperative ETV	Success rate of postoperative ETV (%)
Sainte-Rose et al. [22]	4	159	26	9	100
Ruggiero et al. [21]	3	46	6	4	50
Fritsch et al. [27]	4	52	6	2	100
Morelli et al. [8]	15	114	17	8	100
Due-Tonnessen and Helseth [38]	13	69	34	2	100
Tamburrini et al. [25]	6	104	30	30	90

12.3 Conclusion

Previously, before the standardization and advancement of endoscopic interventions, hydrocephalus was a big challenge; but contemporarily endoscopic interventions can be performed safely, efficiently, and in many medical centers. Due to the short-term and long-term effects of hydrocephalus on morbidity and mortality in this patient group, hydrocephalus needs to be handled usually primarily and prior to the tumor itself. Usually the drawbacks for ETV are doing an unnecessary surgery and possible failure, but when compared to the risks of hydrocephalus, doing an ETV is much more safer and should be considered whenever early surgery for the tumor cannot be done. ETV should be considered in persistent postoperative hydrocephalus cases too and, even if preoperative ETV fails, can be tried again. In the group that ETV is not possible or working efficiently, a shunting procedure can be done.

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