1. Middle fossa approach: microsurgical anatomy and surgical technique from the neurosurgical perspective.
- Author
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Tanriover N, Sanus GZ, Ulu MO, Tanriverdi T, Akar Z, Rubino PA, and Rhoton AL Jr
- Subjects
- Adult, Brain anatomy & histology, Brain surgery, Cadaver, Cranial Fossa, Middle diagnostic imaging, Dissection methods, Dura Mater anatomy & histology, Dura Mater surgery, Ear, Inner anatomy & histology, Ear, Inner surgery, Facial Nerve anatomy & histology, Facial Nerve surgery, Geniculate Ganglion anatomy & histology, Geniculate Ganglion surgery, Hearing Loss prevention & control, Humans, Image Processing, Computer-Assisted, Microsurgery instrumentation, Neuroma, Acoustic pathology, Neuroma, Acoustic surgery, Neurosurgical Procedures instrumentation, Petrous Bone anatomy & histology, Petrous Bone diagnostic imaging, Petrous Bone surgery, Postoperative Complications etiology, Postoperative Complications physiopathology, Postoperative Complications prevention & control, Skull Base anatomy & histology, Skull Base diagnostic imaging, Skull Base surgery, Subarachnoid Space anatomy & histology, Subarachnoid Space surgery, Tomography, X-Ray Computed, Trigeminal Ganglion anatomy & histology, Trigeminal Ganglion surgery, Trigeminal Nerve anatomy & histology, Trigeminal Nerve surgery, Cranial Fossa, Middle anatomy & histology, Cranial Fossa, Middle surgery, Microsurgery methods, Neurosurgical Procedures methods, Vestibulocochlear Nerve anatomy & histology, Vestibulocochlear Nerve surgery
- Abstract
Background: The purpose of this study was to call attention to the subtemporal approach directed through the petrous apex to the IAM. We studied the microsurgical anatomy of the middle floor to delineate a reliable angle between the GSPN and the IAM to precisely localize and expose the IAM from above. A new technique for the elevation of middle fossa floor in an anterior-to-posterior direction has also been examined in cadaveric dissections and performed in surgery., Methods: The microsurgical anatomy of the middle fossa floor was studied in 10 adult cadaveric heads (20 sides) after meatal drilling on the middle fossa. Five latex-injected specimens were dissected in a stepwise manner to further define the microsurgical anatomy of the middle fossa approach. The middle fossa approach is illustrated in a patient for the decompression of the facial nerve to demonstrate the surgical technique and limitations of bone removal., Results: Elevation of middle fossa dura in an anterior-to-posterior direction leads to early identification of the GSPN, where the nerve passes under V3. The most reliable and easily appreciated angle to be used in localizing the IAM is between the IAM and the long axis of the GSPN, which is approximately 61 degrees . Beginning drilling the meatus medially at the petrous ridge is safer than beginning laterally, where the facial and vestibulocochlear nerves become more superficial. The cochlea anteromedially, vestibule posterolaterally, and superior semicircular canal posteriorly significantly limit the bone removal at the lateral part of the IAM., Conclusions: The surgical technique for the middle fossa approach which includes an anterior-to-posterior elevation of middle fossa dura starting from the foramen ovale and uses the angle between the IAM and the long axis of the GSPN to localize the meatus from above may be an alternative to previously proposed surgical methods.
- Published
- 2009
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