Surgeries involving the head and brain (cranial surgeries) are the second most commonly monitored using IONM.

Multiple types of surgeries benefit from monitoring for reduced blood flow or oxygen delivery, mechanical injury and functional status of both the brain structures and cranial nerves (nerves that are directly connected to the brain). Locating or 'mapping' specific areas on the surface of the brain that provide specific types of function adds to and improves upon x-rays or imaging alone, especially where imaging cannot identify specific areas because of tumors or other abnormalities.

Select References
Tharin, S. & Golby, A. (2007), 'Functional brain mapping and its applications to neurosurgery.', Neurosurgery 60(4 Suppl 2), 185--201; discussion 201-2.

Learn more about cranial surgeries:
http://www.brainsurgery.com/pubs/24_64_546.cfm