Endoscope-assisted contralateral transmaxillary approach to the clivus and the hypoglossal canal: technical case report

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Clival lesions are still considered surgically complex due to their anatomical location. Critical structures, such as the internal carotid arteries (ICAs), cavernous sinuses, cranial nerves, and brainstem, may be encased within the lesion. Although advances in endoscopic endonasal approaches have provided new routes to these lesions, exposure and resection of clival tumors through the endonasal route remain a technical challenge. Here, the authors report a left-sided endoscopic transmaxillary approach to access the right aspect of the clivus and the hypoglossal canal.

A 35-year-old woman presented with progressive right 6th cranial nerve palsy. MRI revealed a contrast-enhancing right petroclival chondrosarcoma that involved Meckel’s cave and extended into the right hypoglossal canal. An endoscopic-contralateral-transmaxillary approach through a left sublabial incision was used to access the right petroclival region and right hypoglossal canal. A left maxillary osteoplastic flap was elevated to expose the left maxillary sinus. This was followed by a left medial maxillectomy, gaining access to the left posterior nasal cavity. The posterior third of the left inferior turbinate and nasal septum were removed to access the right side of the petroclival region. Near-total resection was achieved without any vascular or neurological complications. A thin shell of residual tumor was left behind due to involvement of vital structures, such as the ICA, and further treated with proton-beam radiotherapy.

The endoscopic-contralateral-transmaxillary approach provides a direct surgical corridor and good lateral visualization of the skull base vasculature. This approach allows wide maneuverability around the ICA and hypoglossal canal, which, in this case, allowed maximal tumor resection with full preservation of neurological function.

ABBREVIATIONS CN = cranial nerve; ICA = internal carotid artery.

Article Information

Correspondence Alfredo Quiñones-Hinojosa: Mayo Clinic, Jacksonville, FL. quinones-hinojosa.alfredo@mayo.edu.

INCLUDE WHEN CITING Published online June 22, 2018; DOI: 10.3171/2018.1.JNS171972.

E.P.P. and D.M. contributed equally to this work.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

© AANS, except where prohibited by US copyright law.



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    Preoperative sagittal (A), coronal (B), and axial (C) T1-weighted images with gadolinium showing a contrast-enhancing lesion at the right petroclival region posterior to the right ICA, consistent with chondrosarcoma. Postoperative sagittal (D), coronal (E), and axial (F) T1-weighted images with gadolinium showing a postresection cavity with optimal decompression.

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    A: Cerebral angiogram (oblique view, right common carotid artery injection). The red square shows anteromedial displacement and flattening of the petrous segment of the right ICA. B: CT angiogram showing distortion of the anatomical location of the petrous segment of the ICA (red square) by the tumor (yellow). C: Occlusion of the right internal jugular vein (blue) right above the jugular foramen. Figure is available in color online only.

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    A: Head CT angiograms showing the proposed contralateral trajectory to approach the right aspect of the clivus and right hypoglossal canal through a left sublabial incision. B: Axial CT angiogram comparing the trajectories and angles from the endoscopic endonasal approach (EEA) (orange) and endoscope-assisted contralateral transmaxillary approach (ECTA; blue). The EEA (orange) provides a good angle of visualization to the medial aspect of the clivus but is limited laterally by the anteriorly displaced carotid artery (red circle). ECTA (blue) provides a proper angle of approach to the medial and lateral regions of the clivus, maintaining the carotid artery at the periphery of the surgical corridor. Figure is available in color online only.

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    A: After a sublabial incision, the anterior maxillary wall is exposed, and an anterior maxillectomy is performed using the ultrasonic drill. B: Once the anterior maxillectomy is completed, the maxillary sinus can be accessed using the endoscope. Figure is available in color online only.

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    ECTA to the clivus. A: Initial inspection inside the left maxillary sinus after the anterior maxillectomy. B: The middle wall of the maxillary sinus has been opened to access the posterior nasal fossa and pharyngeal space. C: Nasopharyngeal mucosa covering the clivus. D: Clivus exposure after removal of the nasopharyngeal mucosa. E: The middle and inferior clivus are drilled for tumor removal. F: The tumor was removed, and the final pathology was confirmed to be a chondrosarcoma. Figure is available in color online only.

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    A: Anterior maxillary bone replacement with titanium plate fixation. B: Closure of sublabial mucosa with absorbable suture. Figure is available in color online only.





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