**4.5 Complication avoidance**

As with other approaches to the skull base, cerebrospinal fluid leak is a common complication of posterior fossa surgery, especially because patients frequently have concomitant hydrocephalus. This is best avoided by multilayer water-tight closure and aggressive treatment of hydrocephalus either with an endoscopic third ventriculostomy, or temporary/permanent CSF diversion. Otorrhea or rhinorrhea after transpetrosal craniotomy can be treated again with CSF diversion, careful attention intraoperatively to packing of the middle ear, and external ear canal closure in persistent cases.

Sinus injury and sinus thrombosis are additional risks given their exposure in majority of posterior fossa approaches. It is advisable to use neuronavigation whenever possible to identify the location of the sinuses prior to performing the craniotomy and to study preoperative imaging to identify any aberrant anatomy such as persistent occipital sinuses or low-lying torcula, both of which may be present in children.
