The use of
endoscopes for surgery of the
cerebellopontine angle tumors is steadily obtaining widespread acceptance. The objective of the present study was a laboratory and clinical evaluation of the safety of the
endoscope-controlled microneurosurgical removal of the intrameatal
vestibular schwannomas through a retrosigmoid approach. The anatomical investigation was done on
formalin-fixed cadaver heads and dry temporal bones. Clinical series included 33 consecutive patients (23 women and 10 men; mean age 50 +/- 15 years). A bayonet-style rigid
endoscope with 70 degrees angle of view and 4 mm outer diameter was found to be optimal for observation of the internal auditory canal. Its insertion in the cerebellopontine cistern should be preferably done under control through an operating microscope.
Endoscope-controlled manipulations necessitate the use of a special holder system, which provides a stable position of the device and allows bimanual manipulations by the surgeon. A thermographic evaluation did not reveal a significant increase of the local temperature due to use of the
endoscope. Use of the
endoscope permitted removal of the
neoplasm from the most lateral part of the internal auditory canal and identification of the nerve of
tumor origin. In total, 28
tumors underwent total removal, and anatomical preservation of the facial nerve was attained in 31 cases. Damage of the facial nerve by the
endoscope was met once. In 8 out of 16 patients, who showed serviceable hearing before surgery, this was preserved after
tumor removal. In conclusion,
endoscope-controlled removal of the intrameatal
vestibular schwannomas seems to be a technically feasible, effective and safe procedure. Nevertheless, good equipment and special training are absolutely necessary for attainment of optimal results.