Perioperative management of hydrocephalus in children with posterior fossa tumors (PFTs) remains challenging. The modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) has been previously described as a useful tool in predicting which children are at higher risk for permanent hydrocephalus following PFT resection and can be used in guiding treatment. The aim of this study was to externally validate this predictive model.
A retrospective review of the children treated in a single unit was conducted, recording all of the mCPPRH parameters (age, preoperative radiological diagnosis, presence of moderate/severe hydrocephalus, transependymal edema, and metastatic disease at the time of diagnosis), the need for a CSF diversion procedure at 6 months, time to surgery, and management of hydrocephalus. A receiver operating characteristic (ROC) curve was plotted using the mCPPRH, age, Evans index (EI), and frontooccipital horn ratio (FOHR), and an area under the curve (AUC) was calculated. A point-biserial correlation was run to determine the relationship between time to surgery, the insertion of an external ventricular drain (EVD), or initial EVD clamping and the development of postoperative persistent hydrocephalus.
From a total of 75 patients (mean age 6.99 years, 62.7% male) who were included in the study, 8 (10.7%) required permanent CSF diversion following PFT resection. The AUC of the ROC curve was 0.618 for the mCPPRH (p = 0.18, SE 0.088, 95% CI 0.446–0.791), 0.633 for age (p = 0.26, SE 0.119, 95% CI 0.4–0.867), 0.604 for the EI (p = 0.34, SE 0.11, 95% CI 0.389–0.818), and 0.663 for the FOHR (p = 0.17, SE 0.121, 95% CI 0.427–0.9). A significant positive correlation between EVD insertion (r = 0.239, p = 0.03) and insertion of a ventriculoperitoneal shunt was found. A negative correlation between the postoperative clamping of the EVD (r = −0.158, p = 0.4) and the time to PFT surgery (r = −0.06, p = 0.6) did not reach statistical significance.
The implementation of the mCPPRH score failed to reliably predict which children would require permanent CSF diversion following PFT resection when applied to this cohort. Clinical judgment remains the mainstay of choosing the perioperative treatment of hydrocephalus.