J Neurol Surg B Skull Base 2015; 76(04): 310-315
DOI: 10.1055/s-0035-1549000
Original Article
Georg Thieme Verlag KG Stuttgart · New York

Comparative Analysis of Transpetrosal Approaches to the Internal Acoustic Meatus Using Three-Dimensional Radio-Anatomical Models

Zsolt Zador
1   Department of Neurosurgery, Lancashire Teaching Hospitals NHS Trust, Preston, Lancashire, United Kingdom
2   Department of Neurosurgery, Manchester Skull Base Unit, Salford Royal Foundation Trust (SRFT), Manchester, United Kingdom
,
John de Carpentier
3   Department of Head and Neck Surgery, Royal Preston, Lancashire, United Kingdom
› Institutsangaben
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Publikationsverlauf

25. April 2014

08. Januar 2015

Publikationsdatum:
27. April 2015 (online)

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Abstract

Background The transcrusal approach that involves partial removal of the labyrinth was recently described to approach lesions of the cerebellopontine angle. It carries the benefit of hearing preservation and was suggested to have equivalent exposure of the petroclival surface compared with the transcochlear/transotic approaches. The current study was designed to assess if the transcrusal approach could achieve as good access to the internal auditory meatus (IAM) as the more destructive translabyrinthine exposure.

Methods Fifty disease-free high-resolution computed tomography scans of the temporal bone were reviewed. Surgical freedom, angle of attack, and angle of trajectory to the internal acoustic canal were measured in three-dimensional models.

Results Surgical freedom and angles of attack showed steady increments with the progression of petrous bone resection from the retrolabyrinthine-transcrusal-translabyrinthine approaches. The angle of access to the IAM axis was dramatically reduced in the translabyrinthine approach compared with the transcrusal and retrolabyrinthine approaches (37.51 ± 5.7, 24.56 ± 4.6, and 3.17 ± 2.85 degrees, respectively; n = 50; average plus or minus standard deviation, p < 0.001).

Conclusion Using this novel radio-anatomical system, we demonstrate the advantage of the translabyrinthine approach to the axis of the internal auditory canal. The transcrusal approach lags behind the translabyrinthine corridor and should be considered alongside the subtemporal and retrosigmoid approaches designed to spare hearing.