J Neurol Surg B Skull Base 2017; 78(S 01): S1-S156
DOI: 10.1055/s-0037-1600764
Poster Abstracts
Georg Thieme Verlag KG Stuttgart · New York

Endoscopic Endonasal Maximal Petrosectomy: Anatomical Investigation and Surgical Relevance

Hamid Borghei-Razavi
1   UPMC Center for Cranial Base Surgery, Pittsburgh, Pennsylvania, United States
,
Huy Q. Truong
1   UPMC Center for Cranial Base Surgery, Pittsburgh, Pennsylvania, United States
,
David Fernandez-Cabral
1   UPMC Center for Cranial Base Surgery, Pittsburgh, Pennsylvania, United States
,
Emrah Celtikci
1   UPMC Center for Cranial Base Surgery, Pittsburgh, Pennsylvania, United States
,
Xi Cai Sun
2   Department of Otolaryngology-Head and Neck Surgery, Fudan University, Eye, Ear, Nose and Throat Hospital, Shanghai Medical College, Shanghai, China
,
Eric W. Wang
1   UPMC Center for Cranial Base Surgery, Pittsburgh, Pennsylvania, United States
,
Carl Snyderman
1   UPMC Center for Cranial Base Surgery, Pittsburgh, Pennsylvania, United States
,
Paul Gardner
1   UPMC Center for Cranial Base Surgery, Pittsburgh, Pennsylvania, United States
,
Juan C. Fernandez-Miranda
1   UPMC Center for Cranial Base Surgery, Pittsburgh, Pennsylvania, United States
› Author Affiliations
Further Information

Publication History

Publication Date:
02 March 2017 (online)

 

Background: The endoscopic endonasal approach was recently added to the neurosurgical armamentarium as an alternative approach to the petrous apex region. However, the maximal extension, anatomical correlations, limitations, and indications of this surgical procedure remain to be established. The aim of this study is to describe the relevant surgical anatomy to perform an endoscopic endonasal maximal anterior petrosectomy, to determine its limitations, and to discuss the surgical relevance of this procedure for different petroclival lesions.

Method: Five injected anatomical specimens were employed to perform an endoscopic endonasal approach to the petrous apex (PA). After exposing the petrous apex, maximal drilling with neurovascular preservation was completed bilaterally in all heads to show the limitations and anatomical correlations. The maximum extension and limitation of the bony resection was evaluated using neuronavigation. The extent of petrous apex bony resection was then evaluated comparing pre-dissection and post-dissection thin-slice CT scans.

Results: In all specimens, the endoscopic endonasal approach was performed with maximal bone removal in the medial and inferior parts of the PA. The extent of PA drilling was evaluated with image guidance and post-dissection CT scan. The main limitation to further extend drilling in the medial aspect of the PA was the paraclival ICA anteriorly, the lacerum ICA inferiorly, and the abducens nerve at petrous apex superiorly. Full skeletonization of the paraclival ICA, including exposure of the middle cranial fossa dura laterally and lingual process removal, allowed for further access and drilling to the medial aspect of the petrous apex. The main limitation to further extend drilling in the inferior aspect of the PA was the lacerum segment of the ICA and the lacerum foramen fibrous tissue. The transection of the pterygo-sphenoidal fissure at the foramen lacerum and its disconnection from the Eustachian tube cartilage is the key step to perform a sublacerum approach, which greatly enhances access to the inferior aspect of the PA. Once the sublacerum approach is completed, the petrous apex can be drilled until the horizontal petrous ICA is encountered superiorly and laterally. The sublacerum approach also greatly enhances access to the medial aspect of the PA by allowing further mobilization of the paraclival ICA. Other than anatomical limitations, we describe instrumentation aspects than need to be improved, and we propose the design of high-speed drills and ultrasonic bone curettes with distal curvature to facilitate access behind the paraclival ICA and below the lacerum ICA. Based on the surgical anatomy and technical nuances described here, we present several case illustrations to discuss selection criteria and indications.

Conclusion: The endoscopic endonasal approach provides access to the medial and inferior aspects of the PA. Several technical maneuvers, including paraclival and lacerum ICA skeletonization, sublacerum approach, and lingual process removal, are key to maximize PA drilling. Further development in instrumentation is needed to continue improving the endonasal approach to extradural and intradural petroclival lesions.