**2.5 Complication avoidance**

Carotid artery injury is the most formidable complication of the EEA. Avoidance of carotid artery injury comes from meticulous planning, the use of stereotaxy, and adjunct tools including ultrasonography and fluorescence. Control of carotid artery injury can be achieved by an experienced two-surgeon team, and with coordination with anesthesiology and case support staff. We utilize a carotid artery injury "time out" to rehearse such a scenario in cases where the carotid artery may be encountered. This includes the possibility of endovascular sacrifice of the blood vessel, which is the safest immediate option in brisk bleeds. Endovascular sacrifice should only be attempted after hemorrhage is controlled.

#### **Figure 3.**

*A 7 year old male presented with vision changes and was diagnosed with craniopharyngioma on MRI with contrast (A) sagittal (B) coronal, (C) axial. This was resected by endonasal transsphenoidal approach. Post operative MRI (D-F) after gross total resection. A high flow CSF leak was identified intraoperatively, which was closed with a nasal septal flap and abdominal fat graft.*

#### *Pediatric Skull Base Tumors DOI: http://dx.doi.org/10.5772/intechopen.95605*

High flow venous bleeding should also be avoided, especially during exposure of the anterior intercavernous sinus. Bleeding from a robust intercavernous sinus can be brisk and is best avoided by isolating and dividing the sinus with cuts in the sellar and planum dura before moving forward in the exposure. Hemostatic agents and warm irrigation can aid in hemostasis from venous bleeding. Finally, while rare, carotid-cavernous fistula should be suspected in patients with mid-face or skull base trauma, and if present, treated before tumor resection is attempted.

CSF leaks are best avoided by respecting the arachnoid planes of dissection surrounding the tumor and sella. Entry into a subarachnoid cistern or ventricle can predict a CSF leak with confidence. We do not routinely use lumbar drainage for peri-operative care, unless such a leak is expected or encountered by misadventure. High flow CSF leaks can be addressed by raising a nasoseptal or turbinate flap for closure, though as described above, development of the septum and turbinates may lag behind development of the skull base and limit coverage of the flap (**Figure 3**).

Persistent leak can predispose a patient to developing tension pneumocephalus. Multi-layered closure can help prevent this rare complication, which is thought to arise from a ball-valve effect of air entry into the resection bed and intracranial compartment. CSF leaks can also confer a risk for meningitis and ventriculitis, and positive pressure ventilation (CPAP) is strictly avoided peri-operatively.
