Three-dimensional and 2-dimensional endoscopic exposure of midline cranial base targets using expanded endonasal and transcranial approaches.
OBJECTIVE
Endoscopic endonasal approaches provide an access method to the midline cranial base. To integrate these approaches into neurosurgical practice, the extent of their anatomic exposure must be compared with that provided by more traditional transcranial approaches.


METHODS
Ten fresh cadaver heads were studied. Both endonasal and transcranial approaches to the midline cranial base were performed. The midline cranial base was divided into several areas, and the relative exposure provided by each approach was described and presented in both 2-dimensional and 3-dimensional images. Limitations and advantages of each approach are discussed.


RESULTS
The endonasal approaches achieved a direct and wide exposure of the midline extracranial and intracranial cranial base anatomy. The main lateral limitations of the endonasal approaches were the optic nerves, lateral cavernous sinus, vidian nerve, internal carotid artery, abducens nerve in Dorello's canal, jugular tubercle, and hypoglossal canals. Limitations of the transcranial approaches were the neurovascular structures which lie in the operative corridor and create narrow working spaces.


CONCLUSIONS
The endonasal approaches achieve a direct and wide exposure of the midline cranial base bilaterally. Lateral exposure, beyond the cranial nerves and carotid artery, are challenging. Transcranial approaches are limited by the narrow corridors provided by the cranial nerves, and they do not visualize the contralateral paramedian cranial base very well. Three-dimensional endoscopes augment the spatial orientation and may improve patient safety and the learning curve for endoscopic approaches to the midline cranial base.
Roth
Jonathan
J
Department of Neurological Surgery, Weill Medical College of Cornell University, New York Presbyterian Hospital, New York, New York 10021, USA.
Singh
Ameet
A
Nyquist
Gurston
G
Fraser
Justin F
JF
Bernardo
Antonio
A
Anand
Vijay K
VK
Schwartz
Theodore H
TH
D002102:Cadaver; D004724:Endoscopy / Q000379:methods*; D006801:Humans; D009296:Nasal Cavity / Q000033:anatomy & histology / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000379:methods*; D019291:Skull Base / Q000033:anatomy & histology / Q000601:surgery*