Article
Useful microanatomical landmarks for the transsylvian approach to the temporomesial region and their correlation to intraoperative findings
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Authors
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K. Daniel Martin
- Klinik und Poliklinik für Neurochirurgie, Carl Gustav Carus Universitätsklinik, Technische Universität Dresden, Deutschland
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Matthias Kirsch
- Klinik und Poliklinik für Neurochirurgie, Carl Gustav Carus Universitätsklinik, Technische Universität Dresden, Deutschland
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Aksels Ribenis
- Klinik und Poliklinik für Neurochirurgie, Paul Stradins-Universität von Riga, Lettland
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Gabriele Schackert
- Klinik und Poliklinik für Neurochirurgie, Carl Gustav Carus Universitätsklinik, Technische Universität Dresden, Deutschland
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Peter A. Winkler
- Klinik und Poliklinik für Neurochirurgie und Epilepsiechirurgie, Labor für Neurochirurgische Mikroanatomie, Schön Kliniken, Behandlungszentrum Vogtareuth, Deutschland
| Published: | September 16, 2010 |
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Outline
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Objective: Valuable landmarks in the depth of the insula and the temporomesial region are lacking so far. The transsylvian approach for the selective amygdalohippocampectomy and for removal of the hippocampal und parahippocampal gyrus was investigated. Even though the approach is used in many centers there is still a need for exact and reproducible microanatomical neurovascular landmarks.
Methods: In order to define new and valuable microanatomical landmarks 30 hemispheres of human brains were studied using MRI and subsequently microsurgically measured and dissected. The cortical structures were measured. The transsylvian approach for the selective amygdalohippocampectomy and for removal of the hippocampal und parahippocampal gyrus was chosen and documented under microscope. Different types of the Sylvian fissure were classified. The results obtained in the laboratory were compared with 19 intraoperative exposures.
Results: The left temporal lobe is larger than the right one [p=4.6%]. The superficial veins of the Sylvian fissure are classifiable according to the proposal of Yasargil into types A through C: Type A (46.7%): No overlapping of the Sylvian fissure by the frontal and/or temporal lobes, opening of the Sylvian fissure via separation of opercula achieved easily. Type B (36.7%): Indentation of operculum frontale under the superficial level of the Sylvian fissure in direction of the temporal lobe, opening difficult. Type C (16.6%): Indentation of the operculum temporale under the superficial level of the Sylvian fissure in direction of the temporal lobe, opening difficult. Furthermore an inferior insular vein draining the inferior insula at the level of the sulcus limitans laterally from the middle cerebral artery (MCA) in 23 of the 30 investigated hemispheres (76.6%) was found as a new landmark for entering via temporal stem into the temporal horn of the ventricle and for exposure of the ammons horn and the amygdalon. In 17 of 19 patients the vein was found in the groove of the limen insulae.
Conclusions: Just the superior temporal gyrus is constant and reproducible. The differentiation of the types A through C of Sylvian fissure is of crucial practical importance to estimate in advance the difficulties of opening of the Sylvian fissure. The inferior insular vein, always located laterally from the MCA and in the groove of the limen insulae proved to be a useful landmark for entering the temporal horn via temporal stem and for exposure of the temporomesial structures.
