Microsurgical anatomy of the transcallosal anterior interforniceal approach to the third ventricle.
OBJECTIVE
We explored relevant regional microanatomy as it relates to the challenging anterior interforniceal (AIF) approach for removing hypothalamic hamartomas.


METHODS
Five silicone-injected cadaveric heads were dissected by use of frameless stereotactic navigation to reveal microanatomy and extent of exposure through the transcallosal AIF approach. Distances between trajectories to the coronal suture and the genu of the corpus callosum (CC) and between the posterior border of the anterior commissure to the lower end of the rostrum of the CC and posterior border of the foramen of Monro were measured.


RESULTS
The AIF approach provided adequate access to the anterior third ventricle and related structures (i.e., hypothalamus, infundibular recess, and mamillary bodies) through the corridor bounded by the anterior commissure anteriorly and the choroid plexus at the foramen of Monro posteriorly. The mean distances from the posterior trajectory to the coronal suture and the genu of the CC were 44.8 mm (range, 43.8-46.2 mm) and 14.88 mm (14.1-15.7 mm), respectively. The mean distance from the anterior trajectory posterior to the coronal suture was 4.66 mm (0-8.9 mm), and 32.6 mm (30.5-33.9 mm) to the genu of the CC. The mean length of callosotomy was 17.52 mm (16.2-19.1 mm). The mean distance between the posterior border of the anterior commissure and the lower end of the rostrum of the CC was 5.22 mm (4.6-5.6 mm), and 10.52 mm (9.7-11.5 mm) to the posterior border of the foramen of Monro.


CONCLUSIONS
The technically safe AIF approach permitted limited interforniceal splitting, no major deep vein manipulation, and adequate visualization of the hypothalamus, infundibular recess, and mamillary bodies.
Siwanuwatn
Rungsak
R
Division of Neurological Surgery, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Deshmukh
Pushpa
P
Feiz-Erfan
Iman
I
Rekate
Harold L
HL
Zabramski
Joseph M
JM
Spetzler
Robert F
RF
Rosenfeld
Jeffrey V
JV
D002102:Cadaver; D003337:Corpus Callosum / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000601:surgery; D004210:Dissection; D020712:Fornix, Brain / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008866:Microsurgery; D038361:Neuronavigation; D019635:Neurosurgical Procedures; D013238:Stereotaxic Techniques; D020542:Third Ventricle / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed