gms | German Medical Science

Objective: External ventricular drainage (EVD) placement is an established emergency surgical procedure for the treatment of obstructive hydrocephalus and is oftentimes performed in resection of posterior fossa tumors prophylactically to avoid the risk of an acute hydrocephalus. In this prospective observational study we sought to identify factors associated with the necessity of an EVD placement in these patients.

Methods: A prospective observational study was performed at our department between 2012 and 2017. In total 197 patients who underwent resection of a posterior fossa tumor were eligible for analysis and underwent either EVD placement, burrhole trepanation only for a possible rapid insertion of an EVD upon the detection of hydrocephalus or neither of the above-mentioned procedures. EVD placement or burr-hole trepanation was at the discretion of the surgeon. We then assessed the amount of CSF drainage (if applicable), the necessity to place an EVD at a later time point and screened for factors associated with CSF drainage. We noted complications associated with EVD placement and determined shunt dependency within 6 months.

Results: Of the 197 patients assessed, 139 patients (70.6%) received an EVD. Of the patients with EVD placement, temporary CSF drainage was necessary in 58 patients (29.4%). Of the patients with prophylactic burr-hole, one patient (3.2%) required EVD placement to treat acute hydrocephalus. None of the patients without EVD or burr-hole developed hydrocephalus. According to uni- and multivariate analyses independent predictors for the occurrence of hydrocephalus requiring CSF drainage were petroclival tumor location (OR 7.5), midline tumor (OR 2.3), peritumoral edema (OR 3.5) and prone position for surgery (OR 3.6). The overall complication rate of an EVD was 4.3% including meningitis, intracranial hemorrhage and wound healing disturbances impairment. At six months follow-up, 14 patients (10.1%) were shunt-dependent.

Conclusion: We identified risk factors for the development of postoperative hydrocephalus in patients undergoing posterior fossa tumor resection. Patients with petroclival or midline located tumors, peritumoral edema and patients who undergo surgery in a prone-position have a greater risk of hydrocephalus. EVD placement may be waived in low-risk patients.