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Middle fossa approach: microsurgical anatomy and surgical technique from the neurosurgical perspective.
Surg Neurol 2009; 71(5):586-96; discussion 596SN

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.

Authors+Show Affiliations

Department of Neurosurgery, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey. nctan27@yahoo.comNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

18617228

Citation

Tanriover, Necmettin, et al. "Middle Fossa Approach: Microsurgical Anatomy and Surgical Technique From the Neurosurgical Perspective." Surgical Neurology, vol. 71, no. 5, 2009, pp. 586-96; discussion 596.
Tanriover N, Sanus GZ, Ulu MO, et al. Middle fossa approach: microsurgical anatomy and surgical technique from the neurosurgical perspective. Surg Neurol. 2009;71(5):586-96; discussion 596.
Tanriover, N., Sanus, G. Z., Ulu, M. O., Tanriverdi, T., Akar, Z., Rubino, P. A., & Rhoton, A. L. (2009). Middle fossa approach: microsurgical anatomy and surgical technique from the neurosurgical perspective. Surgical Neurology, 71(5), pp. 586-96; discussion 596. doi:10.1016/j.surneu.2008.04.009.
Tanriover N, et al. Middle Fossa Approach: Microsurgical Anatomy and Surgical Technique From the Neurosurgical Perspective. Surg Neurol. 2009;71(5):586-96; discussion 596. PubMed PMID: 18617228.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Middle fossa approach: microsurgical anatomy and surgical technique from the neurosurgical perspective. AU - Tanriover,Necmettin, AU - Sanus,Galip Zihni, AU - Ulu,Mustafa Onur, AU - Tanriverdi,Taner, AU - Akar,Ziya, AU - Rubino,Pablo A, AU - Rhoton,Albert L,Jr Y1 - 2008/07/09/ PY - 2007/11/18/received PY - 2008/04/15/accepted PY - 2008/7/12/pubmed PY - 2009/7/16/medline PY - 2008/7/12/entrez SP - 586-96; discussion 596 JF - Surgical neurology JO - Surg Neurol VL - 71 IS - 5 N2 - 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. SN - 0090-3019 UR - https://www.unboundmedicine.com/medline/citation/18617228/Middle_fossa_approach:_microsurgical_anatomy_and_surgical_technique_from_the_neurosurgical_perspective_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0090-3019(08)00408-4 DB - PRIME DP - Unbound Medicine ER -