Multiportal Endoscopic Approaches to the Central Skull Base: A Cadaveric Study Jeremy N. Ciporen 1 , Kris S. Moe 2 , Dinesh Ramanathan 1 , Sebastian Lopez 1 , Ernesto Ledesma 1 , Robert Rostomily 1 , Laligam N. Sekhar 1 INTRODUCTION Common among the newer techniques in skull base surgery is an effort to avoid a “craniofacial” resection with its scars and the morbidity caused by frontal lobe retrac- tion. Although a certain amount of retrac- tion is required at the site of the target pa- thology for manipulation, there needs not be a significant amount of “collateral dam- age” caused by development of the surgical pathway to the target. Hence there is a nota- ble interest toward the reduction in the size of craniotomy opening, and where possi- ble, the use of endoscopy for access to and manipulation of the surgical targets, to avoid standard craniotomies. Endoscopic transnasal approaches are now in common use for access to the central anterior cranial fossa. These routes to the sella, suprasellar, and clivus regions have been described in both clinical articles and  BACKGROUND: There has been marked evolution in techniques in skull base surgery including the development of minimally invasive endoscopic supraorbital, transnasal, and more recently, transorbital approaches. These have been typically described as isolated, rather than concerted approaches. It is possible that rather than using these approaches alone, they could be combined with transnasal approaches to provide improved manipulation angles, shorter working distances, and optimal visual- ization of the pathology. The primary objective of this study is therefore to determine whether these pathways can be combined in “multiportal” approaches to further improve the surgeon’s ability to access and manipulate pathology in the central anterior cranial fossa.  METHODS: A study was performed on five cadaver heads. Each cadaver underwent an expanded endoscopic binasal approach with clivectomy, bilateral precaruncular transorbital approaches, and bilateral supraorbital craniotomies through an eyebrow incision. A total of 25 procedures were performed. Five endonasal, 10 transorbital, and 10 supraorbital procedures were performed using 0- and 45-degree 4-mm rigid endoscopes. Measurements were obtained from the nasal spine and anterior lacrimal crest to the pituitary gland (PG), optic chiasm (OC), and ipsilateral cavernous carotid artery (IpsiCavCa). Measurements from the anterior border of the orbital roof through the supraorbital approach to the PG and OC were also performed. Photographs were taken to demonstrate these approaches and angles of visualization.  RESULTS: The precaruncular transorbital approach provided a uniformly shorter distance to the PG, OC, and IpsiCavCa compared with the endoscopic transnasal approach. The difference in the mean distances between these two approaches in the left and right sides were 2.38 cm ( P.000) and 2.56 cm ( P.000), respectively. The supraorbital approach to the PG and OC was shorter than the transnasal by a mean difference of 1.92 cm ( P.000) and 1.99 cm ( P.000) on the right and left side, respectively. There was no significant difference in the mean distances to the PG and the OC between the transorbital and supraorbital approaches. Use of these approaches in tandem provided an extra working port by which structures above and below the target organ were better visualized and more easily dissected with two-handed microsurgical techniques than through a single approach.  CONCLUSIONS: The precaruncular transorbital approach provided rapid, direct, coplanar access to the clivus, sella, and suprasellar/parasellar regions. The supraorbital minicraniotomy augmented access to the planum sphenoidale, sella, tuberculum sella, and suprasellar regions. These approaches provided shorter working distances, im- proved visualization, and working angles that offer more direct access to the pituitary gland, suprasellar region, clivus, medial and lateral cavernous sinus than the endoscopic transnasal approach alone. The combination of endoscopic approaches to the central anterior skull base significantly improved instrument access, particularly to lateral targets, as well as better visualization of the vital structures in these regions. These ports provide the surgeon with a more expansive surgical field and improved the ability to perform two-handed microsurgical dissections. Key words  Central skull base approaches  Endoscopic approaches  Endoscopic transnasal approach  Minimally invasive surgery  Supraorbital approach  Transorbital approach Abbreviations and Acronyms ACA: Anterior cerebral arteries AComm: Anterior communicating artery ICA: Internal cerebral artery IpsiCavCa: Ipsilateral cavernous carotid artery MC: Medial canthus NC: Nasal crest OC: Optic chiasm PG: Pituitary gland From the Departments of 1 Neurological Surgery and 2 Head and Neck Surgery, The University of Washington School of Medicine, Seattle, Washington, USA To whom correspondence should be addressed: Laligam N. Sekhar, M.D. [E-mail: lsekhar@u.washington.edu] Citation: World Neurosurg. (2010) 73, 6:705-712. DOI: 10.1016/j.wneu.2010.03.033 Supplementary digital content online Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter Published by Elsevier Inc. PEER-REVIEW REPORTS WORLD NEUROSURGERY 73 [6]: 705-712, JUNE 2010 www.WORLDNEUROSURGERY.org 705