In large/compressive, trigeminal nerve deficit has to be sought to avoid corneal complications in particular. Trigeminal hypoesthesia occurs preoperatively in about half of the cases. It remains relatively stable after tumor removal, but there appears to be an increased rate of absentcorneal reflex and neurotrophic keratitis postoperatively. Karkas et al. were able to correlate pre/postoperative trigeminal hypoesthesia with pre/postoperative MRI findings 2).
Patients receiving > 13 Gy were significantly more likely to develop trigeminal nerve neuropathy than those receiving < 13 Gy (p < 0.001) 5).