Does pre-resection endoscopic third ventriculostomy prevent the need for post-resection CSF diversion after pediatric posterior fossa tumor excision? A historical cohort study and review of the literature

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Children with posterior fossa tumors (PFTs) may present with hydrocephalus. Persistent (or new) hydrocephalus is common after PFT resection. Endoscopic third ventriculostomy (ETV) is sometimes performed prior to resection to 1) temporize hydrocephalus prior to resection and 2) prophylactically treat post-resection hydrocephalus. The objective of this study was to establish, in a historical cohort study of pediatric patients who underwent primary craniotomy for PFT resection, whether or not pre-resection ETV prevents the need for post-resection CSF diversion to manage hydrocephalus.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>The authors interrogated their prospectively maintained surgical neuro-oncology database to find all primary PFT resections from a single tertiary pediatric neurosurgery unit. These data were reviewed and supplemented with data from case notes and radiological review. The modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) score was retrospectively calculated for all patients. The primary outcome was the need for any form of postoperative CSF diversion within 6 months of PFT resection (including ventriculoperitoneal shunting, ETV, external ventricular drainage [EVD], and lumbar drainage [LD]). This was considered an ETV failure in the ETV group. The secondary outcomes were time to CSF diversion, shunt dependence at 6 months, and complications of ETV. Statistical analysis was done in RStudio, with significance defined as p &lt; 0.05.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>A total of 95 patients were included in the study. There were 28 patients in the ETV group and 67 in the non-ETV group. Patients in the ETV group were younger (median age 5 vs 7 years, p = 0.04) and had more severe preoperative hydrocephalus (mean frontal-occipital horn ratio 0.45 vs 0.41 in the non-ETV group, p = 0.003) and higher mCPPRH scores (mean 4.42 vs 2.66, p &lt; 0.001). The groups were similar in terms of sex and tumor histology. The overall rate of post-resection CSF diversion of any kind (shunt, repeat ETV, LD, or EVD) in the entire cohort was 25.26%. Post-resection CSF diversion was needed in 32% of patients in the ETV group and in 22% of the patients in the non-ETV group (p &gt; 0.05). Shunt dependence at 6 months was seen in 21% of the ETV group and 16% of the non-ETV group (p &gt; 0.05). The median time to ETV failure was 9 days. ETV failure correlated with patients with ependymoma (p = 0.02). Children who had ETV failure had higher mCPPRH scores than the ETV success group (5.67 vs 3.84, p = 0.04).</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>Pre-resection ETV did not reliably prevent the need for post-resection CSF diversion. ETV was more likely to fail in children with ependymoma and those with higher mCPPRH scores. Based on the findings of this study, the authors will change the practice at their institution; pre-resection ETV will now be performed based on a newly defined protocol.</jats:p></jats:sec>

Fourth ventricle tumors in children: complications and influence of surgical approach

“…The proportion of patients receiving shunts was higher compared with those who had not had a prior ETV (24/144, 16.7%; difference in proportions 21.4%, 95% CI 2.7%-43.1%, p = 0.0429), although this did not reach a level of statistical significance after multiple comparison correction. These findings are similar to those previously reported 17 and indicate the need for careful patient selection for preresection ETV.…”

Posterior fossa ependymomas in children: still a challenge for pediatric neurosurgeons and oncologists.

“…In our series, an ETV was realized in 43.75% of patients before surgery to avoids high ICP during tumor resection and post-operative complications. ETV in infants with EpFCP [28] provides a reduction of shunts in our series. However, a shunt may be necessary despite ETV and surgical removal of the tumor.…”

The role of external ventricular drainage for the management of posterior cranial fossa tumours: a systematic review

“…EVD or VPS placement before tumour removal is a diffuse practice in paediatric population that cannot be considered an unnecessary surgical procedure such as in adults, because of the higher percentage of persistent hydrocephalus in children [6,17,19,57,63]. Preoperative ETV failure in posterior fossa tumour surgery has been largely described [38,57,58,61,66], and prone position may contribute to determining stoma occlusion for blood clot deposition (snow glob effect) [61]. A recent study by Srinivasan et al [58] analysed the utility of preoperative ETV, observing that it does not prevent the need for post-resection CSF shunt and that ETV failure is higher in case of posterior fossa ependymoma surgery.…”

“…Preoperative ETV failure in posterior fossa tumour surgery has been largely described [38,57,58,61,66], and prone position may contribute to determining stoma occlusion for blood clot deposition (snow glob effect) [61]. A recent study by Srinivasan et al [58] analysed the utility of preoperative ETV, observing that it does not prevent the need for post-resection CSF shunt and that ETV failure is higher in case of posterior fossa ependymoma surgery.…”

“…Summarising, ETV represents a good option for the treatment of postoperative persistent hydrocephalus (as an alternative to VPS), being successful in 90% of cases, although it should not be suggested as first option before posterior fossa tumour removal [17,57,58,62].…”