Intraoperative computed tomography registration and electromagnetic neuronavigation for transsphenoidal pituitary surgery: accuracy and time effectiveness

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The authors assessed the feasibility, anatomical accuracy, and cost effectiveness of frameless electromagnetic (EM) neuronavigation in conjunction with portable intraoperative CT (iCT) registration for transsphenoidal adenomectomy (TSA).


A prospective database was established for data obtained in 208 consecutive patients who underwent TSA in which the iCT/EM navigation technique was used. Data were compared with those acquired in a retrospective cohort of 65 consecutive patients in whom fluoroscope-assisted TSA had been performed by the same surgeon. All patients in both groups underwent transnasal removal of pituitary adenomas or neuroepithelial cysts, using identical surgical techniques with an operating microscope. In the iCT/EM technique–treated cases, a portable iCT scan was obtained immediately prior to surgery for registration to the EM navigation system, which did not require rigid head fixation. Preexisting (nonnavigation protocol) MR imaging studies were fused with the iCT scans to enable 3D navigation based on MR imaging data. The accuracy of the navigation system was determined in the first 50 iCT/EM cases by visual concordance of the navigation probe location to 5 preselected bony landmarks. For all patients in both cohorts, total operating room time, incision-to-closure time, and relative costs of imaging and surgical procedures were determined from hospital records.


In every case, iCT registration was successful and preoperative MR images were fused to iCT scans without affecting navigation accuracy. There was 100% concordance between probe tip location and predetermined bony loci in the first 50 cases involving the iCT/EM technique. Total operating room time was significantly less in the iCT/EM cases (mean 108.9 ± 24.3 minutes [208 patients]) compared with the fluoroscopy group (mean 121.1 ± 30.7 minutes [65 patients]; p < 0.001). Similarly, incision-to-closure time was significantly less for the iCT/EM cases (mean 61.3 ± 18.2 minutes) than for the fluoroscopy cases (mean 71.75 ± 19.0 minutes; p < 0.001). Relative overall costs for iCT/EM technique and intraoperative C-arm fluoroscopy were comparable; increased costs for navigation equipment were offset by savings in operating room costs for shorter procedures.


The use of iCT/MR imaging–guided neuronavigation for transsphenoidal surgery is a time-effective, cost-efficient, safe, and technically beneficial technique.

Abbreviations used in this paper: iCT = intraoperative CT; EM = electromagnetic; TSA = transsphenoidal adenomectomy.

Article Information

Address correspondence to: Marc R. Mayberg, M.D., Swedish Neuroscience Institute, 500 17th Avenue, Suite #500, Seattle, Washington 98122. email:

Please include this information when citing this paper: published online June 18, 2010; DOI: 10.3171/2010.5.JNS091821.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    Setup for EM neuronavigation. An EM localizer is attached to the forehead and an EM generator placed adjacent to the head. Note that the head and generator are not rigidly fixed and can be repositioned after the registration is completed.

  • View in gallery

    Electromagnetic navigation probes. Note that the probe can be bent behind the EM transmitters (red) to provide nonlinear navigation.

  • View in gallery

    Intraoperative verification of accuracy. The navigation probe tip is touching the apex of the sphenoid rostrum, which is delineated in axial (C), coronal (A), and sagittal (B) views on the navigation display derived from CT data set. The 3D rendering (D) is used for surface fiducial tracing.



Ahn JYJung JYKim JLee KSKim SH: How to overcome the limitations to determine the resection margin of pituitary tumours with low-field intra-operative MRI during transsphenoidal surgery: usefulness of Gadolinium-soaked cotton pledgets. Acta Neurochir (Wien) 150:7637712008


Cappabianca PCavallo LMde Divitiis E: Endoscopic endonasal transsphenoidal surgery. Neurosurgery 55:9339412004


Cunningham EMayberg MRTranssphenoidal hypophysectomy. Barnett GHMaciunas RJRoberts DW: Computer-Assisted Neurosurgery New YorkTaylor & Francis Group2006. 209220


Elias WJChadduck JBAlden TDLaws ER Jr: Frameless stereotaxy for transsphenoidal surgery. Neurosurgery 45:2712771999


Fatemi NDusick JRde Paiva Neto MAKelly DF: The endonasal microscopic approach for pituitary adenomas and other parasellar tumors: a 10-year experience. Neurosurgery 63:4 Suppl 22442562008


Gerlach Rdu Mesnil de Rochemont RGasser TMarquardt GReusch JImoehl L: Feasibility of Polestar N20, an ultra-low-field intraoperative magnetic resonance imaging system in resection control of pituitary macroadenomas: lessons learned from the first 40 cases. Neurosurgery 63:2722852008


Hardy J: Neuronavigation in pituitary surgery. Surg Neurol 52:6486491999


Hardy JWigser SM: Trans-sphenoidal surgery of pituitary fossa tumors with televised radiofluoroscopic control. J Neurosurg 23:6126191965


Hayhurst CByrne PEldridge PRMallucci CL: Application of electromagnetic technology to neuronavigation: a revolution in image-guided neurosurgery. Technical note. J Neurosurg 111:117911842009


Heilman CBShucart WARebeiz EE: Endoscopic sphenoidotomy approach to the sella. Neurosurgery 41:6026071997


Jagannathan JPrevedello DMAyer VSDumont ASJane JALaws ER: Computer assisted frameless stereotaxy in transsphenoidal surgery at a single institution: review of 176 cases. Neurosurg Focus 20:2E92006


Jane JA JrThapar KAlden TDLaws ER Jr: Fluoroscopic frameless stereotaxy for transsphenoidal surgery. Neurosurgery 48:130213082001


Kawamata TIseki HShibasaki THori T: Endoscopic augmented reality navigation system for endonasal transsphenoidal surgery to treat pituitary tumors: technical note. Neurosurgery 50:139313972002


Mayberg MRLaPresto ECunningham EJ: Image-guided endoscopy: description of technique and potential applications. Neurosurg Focus 19:1E102005


McCutcheon IEKitagawa RSDemasi PFLaw BKFriend KE: Frameless stereotactic navigation in transsphenoidal surgery: comparison with fluoroscopy. Stereotact Funct Neurosurg 82:43482004


Nimsky CGanslandt OFahlbusch R: Comparing 0.2 tesla with 1.5 tesla intraoperative magnetic resonance imaging analysis of setup, workflow, and efficiency. Acad Radiol 12:106510792005


Nimsky CGanslandt OVon Keller BRomstöck JFahlbusch R: Intraoperative high-field-strength MR imaging: implementation and experience in 200 patients. Radiology 233:67782004


Ohhashi GKamio MAbe TOtori NHaruna S: Endoscopic transnasal approach to the pituitary lesions using a navigation system (InstaTrak system): technical note. Minim Invasive Neurosurg 45:1201232002


Onizuka MTokunaga YShibayama AMiyazaki H: Computer-assisted neurosurgical navigational system for transsphenoidal surgery—technical note. Neurol Med Chir (Tokyo) 41:5655692001


Rosenow JMSootsman WK: Application accuracy of an electromagnetic field-based image-guided navigation system. Stereotact Funct Neurosurg 85:75812007


Rothman SLKier ELAllen WE III: The radiology of transsphenoidal hypophysectomy: a review of 100 cases. AJR Am J Roentgenol 127:6016061976


Schulder MSernas TJCarmel PW: Cranial surgery and navigation with a compact intraoperative MRI system. Acta Neurochir Suppl (Wien) 85:79862003


Shamir RRFreiman MJoskowicz LSpektor SShoshan Y: Surface-based facial scan registration in neuronavigation procedures: a clinical study. Clinical article. J Neurosurg 111:120112062009


Spencer WRDas KNwagu CWenk ESchaefer SDMoscatello A: Approaches to the sellar and parasellar region: anatomic comparison of the microscope versus endoscope. Laryngoscope 109:7917941999


Suess OPicht TKuehn BMularski SBrock MKombos T: Neuronavigation without rigid pin fixation of the head in left frontotemporal tumor surgery with intraoperative speech mapping. Neurosurgery 60:4 Suppl 23303382007


Thomale UWStover JFUnterberg AW: The use of neuronavigation in transnasal transsphenoidal pituitary surgery. Zentralbl Neurochir 66:1261322005


Thoranaghatte RGarcia JCaversaccio MWidmer DGonzalez Ballester MANolte LP: Landmark-based augmented reality system for paranasal and transnasal endoscopic surgeries. Int J Med Robot 5:4154222009


Vrionis FDSaatman DSorenson JBrem S: Microscopic paraseptal sphenoidotomy approach for pituitary tumors. Cancer Contr 9:2232312002


Walker DGOhaegbulam CBlack PM: Frameless stereotaxy as an alternative to fluoroscopy for transsphenoidal surgery: use of the InstaTrak-3000 and a novel headset. J Clin Neurosci 9:2942972002


Wolfsberger SNeubauer ABühler KWegenkittl RCzech TGentzsch S: Advanced virtual endoscopy for endoscopic transsphenoidal pituitary surgery. Neurosurgery 59:100110102006


Wu JSShou XFYao CJWang YFZhuang DXMao Y: Transsphenoidal pituitary macroadenomas resection guided by PoleStar N20 low-field intraoperative magnetic resonance imaging: comparison with early postoperative high-field magnetic resonance imaging. Neurosurgery 65:63712009


Zada GKelly DFCohan PWang CSwerdloff R: Endonasal transsphenoidal approach for pituitary adenomas and other sellar lesions: an assessment of efficacy, safety, and patient impressions. J Neurosurg 98:3503582003




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