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Ulm AJ, Russo A, Albanese E, Tanriover N, Martins C, Mericle RM, Pincus D, Rhoton AL. Limitations of the transcallosal transchoroidal approach to the third ventricle. J Neurosurg 2009; 111:600-9. [DOI: 10.3171/2008.7.jns08124] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The aim of this study was to determine the anatomical limitations of the transcallosal transchoroidal approach to the third ventricle.
Methods
Twenty-six formalin-fixed specimens were studied. Sagittal dissections were used to determine the anatomical relationships of the foramen of Monro, the angle of approach to landmarks, and placement of a callosotomy. Lateral ventricular dissections were performed to quantitate the forniceal anatomy.
Results
The foramen of Monro was found 1.07 ± 0.11 cm superior and slightly anterior to the mammillary bodies, 1.48 ± 0.16 cm posterosuperior to the optic recess, and 2.26 ± 0.16 cm anterosuperior to the aqueduct. Relative to the genu, a callosal incision 2.64 ± 0.53 cm long and angled 37 ± 4.3° anterior was needed to access the aqueduct, and an incision 4.92 ± 0.71 cm long and angled 49 ± 7.4° posterior was needed to access the optic recess. The fornix progressively widened within the lateral ventricle, from 1.25 ± 0.63 mm at the foramen of Monro to > 7 mm at 2 cm behind the foramen. Three zones of exposure were identified, requiring unique craniotomies, callosotomies, and angles of approach. The major limiting factors in the approach included the columns of the fornix anteriorly, the width of the fornix posteriorly, and the draining veins of the parietal cortex. The choroidal fissure opening was limited to 1.5 cm posterior to the foramen of Monro; this limited opening created an aperture effect that required an anterior-to-posterior angle, an anterior craniotomy, and an anteriorly placed callosotomy to access the posterior landmarks. In contrast, a posterior-to-anterior angle, posteriorly placed craniotomy, and posteriorly placed callosotomy were required to access anterior landmarks.
Conclusions
The transcallosal transchoroidal approach was ideally suited to access the foramen of Monro and the middle and posterior thirds of the third ventricle. Exposure of the anterior third ventricle was limited by the columns of the fornix and by the presence of parietal cortical draining veins.
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Affiliation(s)
- Arthur J. Ulm
- 1Georgia Neurosurgical Institute, Mercer University School of Medicine, Macon, Georgia
- 2Department of Neurosurgery, Vanderbilt University, Nashville, Tennessee
| | - Antonino Russo
- 1Georgia Neurosurgical Institute, Mercer University School of Medicine, Macon, Georgia
| | - Erminia Albanese
- 1Georgia Neurosurgical Institute, Mercer University School of Medicine, Macon, Georgia
| | - Necmettin Tanriover
- 3Department of Neurosurgery, University of Florida, Gainesville, Florida; and
| | - Carolina Martins
- 3Department of Neurosurgery, University of Florida, Gainesville, Florida; and
| | - Robert M. Mericle
- 2Department of Neurosurgery, Vanderbilt University, Nashville, Tennessee
| | - David Pincus
- 3Department of Neurosurgery, University of Florida, Gainesville, Florida; and
| | - Albert L. Rhoton
- 3Department of Neurosurgery, University of Florida, Gainesville, Florida; and
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Abstract
Object
In this paper the authors correlate the surgical aspects of deep median and paramedian supratentorial lesions with the connective fiber systems of the white matter of the brain.
Methods
The cerebral hemispheres of 10 cadaveric brains were dissected in a mediolateral direction by using the fiber dissection technique, corresponding to the surgical approach.
Conclusions
This study illuminates the delicacy of the intertwined and stratified fiber laminae of the white matter, and establishes that these structures can be preserved at surgical exploration in patients.
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Affiliation(s)
- M Gazi Yaşargil
- Department of Neurosurgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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