Artikel
Endoscopic retrosigmoid intradural suprameatal approach: anatomical considerations
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Veröffentlicht: | 30. Mai 2008 |
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Gliederung
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Objective: To evaluate the feasibility of endoscopic suprameatal tubercle drilling with a retrosigmoid approach. This study focuses on the anatomic structures identified with the endoscope after suprameatal tubercle drilling.
Methods: 50 dry temporal bones were studied in order to estimate the variability of the prominence of the suprameatal tubercle. Then, eight fresh cadaveric heads were prepared for a retrosigmoid approach to allow endoscopic suprameatal tubercle drilling. The increase in trigeminal nerve exposure and neurovascular structures visualization with 0° and 30° lenses was then evaluated.
Results: Three major prominences of the suprameatal tubercle were found: 1) a very large type; 2) a medium size, which we found in the majority of the cases; and 3) an almost absent suprameatal tubercle that almost made drilling unnecessary, in rare cases. Endoscopic suprameatal tubercle drilling with opening of the Meckel's cave was found to be technically feasible in all cases. We obtained an increase in trigeminal nerve exposition of 9 mm on average. Endoscopic exploration of the area with 0° and 30° optics allowed for the identification of the abducens, trochlear and oculomotor nerves, the internal carotid artery (ICA) with the anterior choroidal artery (AChA) and the posterior communicating artery (PComA) reaching the P1 segment of posterior cerebral artery (PCA).
Conclusions: Endoscopic suprameatal tubercle drilling is a feasible procedure that allows for the identification of all neurovascular structures in the cerebello-pontine angle (CPA) and petrous apex region. The opening of Meckel's cave makes this surgical procedure particularly useful for tumors located in the CPA that have a minor component extending anteriorly and laterally in the middle cranial fossa.