The Middle Fossa Approach:
This approach is most commonly used for removal of smaller tumors when hearing is still intact. It is particularly suitable for tumors under 1.5 cm and located deep in the internal auditory canal, close to the inner ear. For a complete history of the development of this approach please see this article by Dr. Monfared (http://www.ncbi.nlm.nih.gov/pubmed/19816222). This approach is also used for removal of acoustic neuromas and other disorders, such as superior semicircular canal dehiscence, encephaloceles and facial nerve decompression.
Advantages of the Middle Fossa Approach:
• Very versatile approach for many disorders including small acoustic neuromas.
• Optimal for hearing preservation
Disadvantages of the Middle Fossa Approach:
• Only useful for tumors smaller than 1.5 cm
• Facial nerve is in a disadvantageous position
• Need for retraction of the dura and the temporal lobe
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| In this approach an incision is made in the hairline above the ear extending down to the top of the ear. The location and length of incision may vary base on the disorder being addressed. | Then a small window is created in the bone which is placed back into its native position at the end of the procedure. The bone plate is secured back with mini-titanium plates and screws. | The bone plate is separated carefully from the sac around the brain known as dura. |
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| Then the dura is lifted off the bone of the floor of the middle fossa (known as the tegmen) to the opening of the internal auditory canal. | Using anatomical landmarks surgeon identifies the important structures beneath the bone seen here. These include the middle ear structures, the cochlea, semicircular canals, and the contents of the internal auditory canal. | Then the roof of the internal auditory canal is drilled away and the tumor removed. |
Images used with permission from Robert K Jackler