Department of Otolaryngology, Tokyo Metropolitan Police Hospital, Tokyo, Japan. k-akinori@mbg.ocn.ce.jp

We report the case of a 39-year-old woman with a left side meningioma, suffering from bilateral sensorineural hearing loss, who recovered audiometric hearing in both ears after surgery. A preoperative pure tone audiogram (PTA) revealed a bilateral sensorineural hearing loss. Several examinations for sensorineural hearing loss indicated cochlear and retrocochlear hearing loss in the left ear and cochlear hearing loss in the right ear. After the operation, bilateral hearing loss due to a left posterior fossa meningioma gradually improved. One year after surgery, with the exception of hearing at frequencies of 4 and 8 kHz in the left ear, the postoperative audiogram had improved to an almost normal level. We speculate that hearing loss in the left ear may have been induced by the indirect compression of the cochlear nerve caused by the tumor’s edema, whereas that in the right ear may have resulted from changes in CSF pressure caused by the mass effects of the tumor.

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Department for Neurology, University Hospital Dubrava, Zagreb, Croatia.

In order to determine possible differences in serum gangliosides content and composition before and after surgical removal of tumor, gangliosides isolated from preoperative and postoperative sera of patients with brain tumors were analyzed. Serum samples were collected from patients with glioblastoma, meningioma, acoustic neurinoma, haemangioma, oligodendroglioma and astrocytoma, one week before and one week after surgical removal of the tumor. Serum gangliosides were qualitatively and quantitatively analyzed by high performance thin layer chromatography and laser densitometry. Results showed changes of total gangliosides concentrations in analyzed postoperative sera comparing to preoperative sera. There was not a significant difference in ganglioside pattern of preoperative vs. preoperative sera. However, a postoperative decreased proportion of ganglioside GD3 was observed in sera derived from patients with complete tumor removal. The results of this study indicate that comparative quantitative and compositional analysis of both preoperative and postoperative serum gangliosides may provide useful information concerning tumor progression, surgical success and prognosis.

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Department of Neurosurgery, Hôpital Gui de Chauliac, CHU de Montpellier, 80 avenue Augustin Fliche, 34295 Montpellier Cedex 5, France. h-duffau@chu-montpellier.fr

Dominant temporal lobectomy is classically performed based on two criteria: a perfect knowledge of the temporo-mesial microsurgical anatomy and cortical landmarks laterally. However, the functional anatomy of the subcortical white matter tracts is taken into account less, despite the risk of inducing a permanent deficit (especially aphasia) if damaged. Even if Klinger’s technique allows dissection of fibres on cadaveric specimens, the exact three dimensional geometry of these fasciculi remains poorly described. Tractography, based on diffusion tensor imaging (DTI), is a powerful tool to build three dimensional images of several fasciculi, helping neurosurgeons to create a mental representation of their relationships. Moreover, intraoperative subcortical electrostimulation enables mapping of the function of these pathways. Here we review the recent findings on the white matter anatomo-functional connectivity of the dominant temporal lobe, based on combined anatomical data provided by DTI and functional information provided by intraoperative stimulation. We then discuss their implications for temporal lobectomy, by using white matter functional connectivity as an additional landmark.

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