title: The transventricular preforniceal approach for exophytic chiasmatic/hypothalamic astrocytomas extending into the anterior third ventricle.
abstract: BACKGROUND
  Surgical treatment of large exophytic chiasmatic/hypothalamic astrocytomas extending into the anterior third ventricle remains a challenging task for neurosurgeons. In particular, when the tumor extends from the chiasmatic region upward to the foramen of Monro, damage to the fornix and other neurovascular structures is a major concern.
  
  
  OBJECTIVE
  To describe the technique used in the transventricular preforniceal surgical approach to remove the superior and superoposterior part of the tumor in the third ventricle for treatment of exophytic chiasmatic/hypothalamic astrocytoma.
  
  
  METHODS
  The transventricular preforniceal approach was used in two cases of exophytic chiasmatic/hypothalamic astrocytoma. The approach is summarized in 4 procedures: 1) exposure of the anterior horn of the lateral ventricle by the transcallosal approach, 2) identification of the foramen of Monro and the fornix, 3) incision of the septum pellucidum or the wall of the lateral ventricle, in front of the columns of the fornix, and 4) removal of the tumor through the space between the anterior commissure and the columns of the fornix.
  
  
  RESULTS
  Because the tumor compressed the foramen of Monro posteriorly and stretched the space between the anterior commissure and the columns of the fornix, the posterosuperior part of the tumor in the third ventricle was successfully removed through the surgical corridor in front of the columns of the fornix. In both cases, tumors were successfully removed using this approach without damaging the fornix and the anterior commissure. Residual tumor was removed using an anterior interhemispheric translamina terminalis approach in a two-stage surgery.
  
  
  CONCLUSIONS
  The transventricular preforniceal approach can be applied for removing the superior part of exophytic chiasmatic/hypothalamic astrocytomas, because the space between the anterior commissure and the fornix is stretched by the tumor, providing an appropriate surgical corridor.
authors: Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. kyoshimo@ns.med.kyushu-u.ac.jp
authors: Koji
authors: K
authors: Yoshimoto
authors: Tadahisa
authors: T
authors: Shono
authors: Koichiro
authors: K
authors: Matsukado
authors: Tomio
authors: T
authors: Sasaki
mesh_terms: D001254:Astrocytoma / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D002551:Cerebral Ventricle Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007031:Hypothalamus / Q000473:pathology* / Q000601:surgery; D007223:Infant; D008297:Male; D020542:Third Ventricle / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome