Endoscopic endonasal skull base surgery: analysis of complications in the authors' initial 800 patients

A review

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The development of endoscopic endonasal approaches, albeit in the early stages, represents part of the continuous evolution of skull base surgery. During this early period, it is important to determine the safety of these approaches by analyzing surgical complications to identify and eliminate their causes.


The authors reviewed all perioperative complications associated with endoscopic endonasal skull base surgeries performed between July 1998 and June 2007 at the University of Pittsburgh Medical Center.


This study includes the data for the authors' first 800 patients, comprising 399 male (49.9%) and 401 female (50.1%) patients with a mean age of 49.21 years (range 3–96 years). Pituitary adenomas (39.1%) and meningiomas (11.8%) were the 2 most common pathologies. A postoperative CSF leak represented the most common complication, occurring in 15.9% of the patients. All patients with a postoperative CSF leak were successfully treated with a lumbar drain and/or another endoscopic approach, except for 1 patient who required a transcranial repair. The incidence of postoperative CSF leaks decreased significantly with the adoption of vascularized tissue for reconstruction of the skull base (< 6%). Transient neurological deficits occurred in 20 patients (2.5%) and permanent neurological deficits in 14 patients (1.8%). Intracranial infection and systemic complications were encountered and successfully treated in 13 (1.6%) and 17 (2.1%) patients, respectively. Seven patients died during the 30-day perioperative period, 6 of systemic illness and 1 of infection (overall mortality 0.9%).


Endoscopic endonasal skull base surgery provides a viable median corridor based on anatomical landmarks and is customized according to the specific pathological process. This corridor should be considered as the sole access or may be combined with traditional approaches. With the incremental acquisition of skills and experience, endoscopic endonasal approaches have an acceptable safety profile in select patients presenting with various skull base pathologies.

Abbreviations used in this paper: AVM = arteriovenous malformation; BA = basilar artery; CA = carotid artery; CN = cranial nerve; EEA = endoscopic endonasal approach; ICA = internal CA; MPW = medial pterygoid wedge; VA = vertebral artery.

Article Information

Current affiliation for Dr. Kassam: University of Ottawa, Ontario, Canada.

Current affiliation for Dr. Prevedello: The Ohio State University, Columbus, Ohio.

Current affiliation for Dr. Carrau: Institute at Saint John's Hospital, Santa Monica, California.

Current affiliation for Dr. Thomas: Beth Israel Deaconness Medical Center, Boston, Massachusetts.

Current institution for Dr. Zanation: University of North Carolina, Chapel Hill, North Carolina.

Address correspondence to: Daniel M. Prevedello, M.D., Department of Neurological Surgery, The Ohio State University, N-1011 Doan Hall, 410 West 10th Avenue, Columbus, Ohio, 43210. email: daniel.prevedello@osumc.edu.

Please include this information when citing this paper: published online December 17, 2010; DOI: 10.3171/2010.10.JNS09406.

© AANS, except where prohibited by US copyright law.



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    Illustration showing the skull base in an inferior view. Each colored area represents a module of expanded endonasal approach at the skull base. CP-AF = coronal plane anterior fossa; CP-MF = coronal plane middle fossa; CP-PF = coronal plane posterior fossa; TC = transclival (pink area); TC = transcribriform (white area); TO = transodontoid; TP/T = transplanum/transtuberculum; TS = transsellar.

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    Transsellar approach. A and B: Coronal (A) and sagittal (B) contrast-enhanced MR images showing preoperative images of a hemorrhagic macroadenoma with suprasellar extension. C and D: Postoperative coronal (C) and sagittal (D) MR images demonstrating complete resection of the lesion and preservation of the pituitary gland at the right side of the sella. E: Intraoperative photograph obtained after resection of the lesion through an endoscopic endonasal transsellar approach. Note the diaphragmatic herniation toward the sphenoid sinus passing the level of the sellar dura.

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    Transplanum approach. A and B: Preoperative, contrast-enhanced T1-weighted coronal (A) and sagittal (B) MR images of a tuberculum sellae meningioma. C and D: Corresponding postoperative coronal (C) and sagittal (D) MR images demonstrating complete resection of the lesion. The arrow in D indicates the reconstruction of the skull base with a vascularized enhanced nasoseptal flap. E: Intraoperative endoscopic view of the suprasellar region after complete extirpation of a tuberculum sellae meningioma, showing the optic chiasm, the pituitary stalk, the ICA on the right side, and the anterior communicating artery (Acom). The pituitary gland is shown in the sella protected by intact dura. The superior hypophysial arteries (SHa) were preserved and are seen bilaterally.

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    Transcribriform approach. A and B: Preoperative axial (A) and coronal (B) T1-weighted, contrast-enhanced MR images of an olfactory groove meningioma. C and D: Postoperative axial (C) and coronal (D) T1-weighted, contrast-enhanced MR images demonstrating complete resection of the lesion. The arrow in D indicates the skull base reconstruction using a vascularized nasoseptal flap. E: Intraoperative photograph of a transcribriform view during sharp dissection of the tumor (meningioma). The interface between the meningioma and the left frontal lobe is visible. The frontopolar artery (art.) is shown over the left gyrus rectus.

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    Transclival approach. A and B: Preoperative axial (A) and sagittal (B) contrast-enhanced, T1-weighted MR images showing a neurenteric cyst. Note the arrows indicating the neurenteric cyst delineated by the yellow dotted lines. C and D: Postoperative axial (C) and sagittal (D) contrast-enhanced, T1-weighted MR images demonstrating complete resection of the lesion. E: Intraoperative oblique, 45° endoscopic view of the prepontine cistern showing the brainstem at the level of the pons, CN V (V), CN VI (VI), and the complex of CNs VII and VIII (VII and VIII).

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    Transodontoid approach. A and B: Preoperative axial (A) and sagittal (B) CT angiograms showing a foramen magnum meningioma. C and D: Postoperative axial (C) and sagittal (D) CT angiograms demonstrating resection of the bone and lesion. E: Intraoperative view of the cervicomedullary junction during resection of a foramen magnum meningioma (Tu). The anterior spinal artery (ASa) is seen ventral to the spinal cord. The inferior rootlet of the hypoglossal nerve is seen on the left side (XII). Note the C-1 ventral root (C1) and the dentate ligament (DL). Bilateral VAs are identified (RVa and LVa).

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    Coronal plane, anterior fossa approach (transorbital). A and B: Preoperative axial non–contrast-enhanced (A) and coronal contrast-enhanced (B) T1-weighted MR images showing an expansive intraconal lesion in the right orbit (arrows) that proved to be a hemangioma. C and D: Postoperative axial non–contrast-enhanced (C) and coronal contrast-enhanced (D) T1-weighted MR images demonstrating total resection of the lesion. (The decompressed right optic nerve can be seen in C.) The yellow arrow indicates the enhancing nasoseptal flap that was used for reconstruction. E: Intraoperative view of the right orbit (RO) from a 45° endoscope, in which the sphenoid sinus (SS) is seen posteriorly. The window used for dissection was between the middle rectus muscle (MRM) and the inferior rectus muscle (IRM). The hemangioma (Tu) is visualized during resection.

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    Coronal plane, middle fossa approach. A and B: Preoperative axial (A) and coronal (B) contrast-enhanced T1-weighted MR images showing an expansive, homogeneously enhancing lesion in the right mesial temporal fossa, which proved to be a trigeminal schwannoma. C and D: Postoperative axial (C) and coronal (D) contrast-enhanced MR images demonstrating complete resection of the lesion through an endonasal route. The yellow arrow indicates the nasoseptal flap that was used for reconstruction. E: Intraoperative view of the Meckel cave (MC) after the trigeminal schwannoma was removed using a 0° endoscope. Note the preserved V1 branch of the trigeminal nerve preserved superiorly in the field at the level of the superior orbital fissure (SOF). The sella is seen posteriorly as well as the clival recess (CR). The right ICA was skeletonized and kept covered by the periosteum of the carotid canal.

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    Coronal plane, posterior fossa approach. A and B: Preoperative axial (A) and coronal (B) T1-weighted contrastenhanced MR images showing a right jugular foramen enhancing lesion, which proved to be a chondrosarcoma. Note the ICA is pushed laterally by the tumor, creating an endonasal corridor for resection (A). C and D: Postoperative axial (C) and coronal (D) contrast-enhanced MR images demonstrating complete resection of the lesion through an endonasal route. The yellow arrow indicates the nasoseptal flap that was used for reconstruction. E: Intraoperative endoscopic view after resection of a posterior fossa lesion using an EEA. Note the right internal auditory canal (IAC) with CNs VII and VIII. Inferiorly, the area of the jugular foramen (JF) is seen with CNs IX and X.

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    Contrast-enhanced MR images of a giant pituitary adenoma. A and B: Preoperative coronal (A) and sagittal (B) images. C and D: Postoperative coronal (C) and sagittal (D) images demonstrating an extensive resection of the tumor with preservation of the pituitary gland.

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    Graph showing the distribution of expanded endoscopic endonasal skull base surgeries during the 1st 9 years of development at University of Pittsburgh Medical Center, divided into levels of complexity (II–V). Cases from 2007 were not included in this graph to avoid confusion since it is represented by a half year in this series. Note that we did not systematically pursue Level IV (intradural) and Level V (paramedian) approaches until the 4th and 5th years of our endoscopic experience, respectively.


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