Search Results

You are looking at 1 - 10 of 204 items for :

  • "parahippocampal gyrus" x
  • All content x
Clear All
Restricted access

Howard L. Weiner and Patrick J. Kelly

T umors of the posterior parahippocampal gyrus represent a formidable technical challenge to neurosurgeons. The proximity of such lesions to vital structures surrounding the posterior mesial temporal lobe in the dominant hemisphere, including the brainstem, cranial nerves, posterior cerebral and anterior choroidal arteries, basal vein of Rosenthal, as well as the vein of Labbé and the language cortex, raises the possibility of potentially disastrous operative morbidity. Several surgical approaches to this region have been described for resecting epileptogenic

Full access

Naoki Tani, Haruhiko Kishima, Hui Ming Khoo, Takufumi Yanagisawa, Satoru Oshino, Tomoyuki Maruo, Koichi Hosomi, Masayuki Hirata, Hiroaki Kazui, Keiko Tokumasu Nomura, Mohamed M. Aly, Amami Kato, and Toshiki Yoshimine

(cathode), and between 5 (anode) and 4 (cathode). Amy = amygdala; ERC = entorhinal cortex; FuG = fusiform gyrus; HpH = hippocampal head. For the provocative test, electrical stimulation was performed in the left parahippocampal gyrus (PHG) during a verbal encoding task. The patient was first asked to memorize 3 target words, each presented for 5 seconds, while his or her left PHG was stimulated. For some patients, depending on the results of the preexamination, only 1 or 2 words were presented. The PHG was stimulated by a pair of adjacent electrodes under the

Restricted access

T. S. Park, Blaise F. D. Bourgeois, Daniel L. Silbergeld, and W. Edwin Dodson

described in this report: via the sylvian fissure, superior temporal sulcus, middle temporal gyrus, fusiform gyrus, and parahippocampal gyrus. Right: Illustration depicting the extent of excision in transparahippocampal amygdalahippocampectomy (A)/(B) and an initial cortical incision to expose the temporal horn. If the dominant temporal lobe is involved, language mapping before excision of epileptogenic areas is recommended. 20 In young children, however, precise language mapping is always challenging and often impossible because of poor cooperation. For

Restricted access

Aaron A. Cohen-Gadol and Dennis D. Spencer

strip implantation involves placement of two electrode strips perpendicular to the long axis of the temporal lobe. These two (anterior and posterior) temporobasal strips allow reasonable coverage of the basal medial temporal lobe cortex. The authors describe the use of an anteromedial strip as an alternative to provide more extensive and consistent coverage of the entorhinal cortex and parahippocampal gyrus. Surgical Indications and Technique The anteromedial strip may be used to evaluate the involvement of medial temporal lobe structures in epileptogenesis

Restricted access

David Satzer, James X. Tao, and Peter C. Warnke

parahippocampal gyrus (PHG). 7 Mesial temporal cortical areas, including the piriform, entorhinal, perirhinal, and parahippocampal cortices, are known to be involved in seizure generation and propagation in MTLE. 16–19 ATL and SelAH both entail resection of the PHG, 4 and piriform cortex resection has been associated with seizure freedom after ATL. 20 However, protocols for SLAH specify the amygdalohippocampal complex (AHC) as the primary target of ablation. 6 , 21 The study by Wu et al. highlighted the importance of mesial temporal regions outside the AHC; however, the

Restricted access

Peter Vajkoczy, Karsten Krakow, Stefan Stodieck, Bernd Pohlmann-Eden, and Peter Schmiedek

cerebellar arteries to its dural exit into the sinus ( Fig. 1E and F ). For the next step, the ambient cistern is opened in its full extent, thus revealing the proximal portion of the P 1 segment. By this maneuver, free access to the mobilized mesial temporal lobe is obtained. Up to this point of the dissection, the microscope has been directed anteroinferiorly. Now it is turned posteroinferiorly, providing an excellent overview of the mesial cortical landmarks, that is, the rhinal sulcus and parahippocampal gyrus ( Fig. 1G and H ). It should be noted, however, that these

Full access

Uğur Türe, Mehmet Volkan Harput, Ahmet Hilmi Kaya, Praveen Baimedi, Zeynep Firat, Hatice Türe, and Canan Aykut Bingöl

T he MTR is actually part of the limbic lobe and includes 2 main portions, the paralimbic areas (mesocortex) and the limbic areas (corticoid and allocortex). The paralimbic areas consist of the temporal pole and the parahippocampal gyrus, and the limbic areas consist of the amygdala, piriform cortex, and the retrocommissural part of the hippocampal formation. 23 , 24 The MTR is roughly limited medially by the lateral wall of the cavernous sinus and the carotid, crural, and ambient cisterns; anteriorly by the lesser wing of the sphenoid bone; and laterally

Full access

T. S. Park, Blaise F. D. Bourgeois, Daniel L. Silbergeld, and W. Edwin Dodson

Amygdalohippocampectomy (AH) is an accepted surgical option for treatment of medically refractory mesial temporal lobe epilepsy. Operative approaches to the amygdala and hippocampus that previously have been reported include: the sylvian fissure, the superior temporal sulcus, the middle temporal gyrus, and the fusiform gyrus. Regardless of the approach, AH permits not only extirpation of an epileptogenic focus in the amygdala and anterior hippocampus, but interruption of pathways of seizure spread via the entorhinal cortex and the parahippocampal gyrus. The authors report a modification of a surgical technique for AH via the parahippocampal gyrus, in which excision is limited to the anterior hippocampus, amygdala and parahippocampal gyrus while preserving the fusiform gyrus and the rest of the temporal lobe. Because transparahippocampal AH avoids injury to the fusiform gyrus and the lateral temporal lobe, it can be performed without intracarotid sodium amobarbital testing of language dominance and language mapping. Thus the operation would be particularly suitable for pediatric patients in whom intraoperative language mapping before resection is difficult.

Restricted access

Shuichi C. Umeoka, Hans O. Lüders, John P. Turnbull, Mohamad Z. Koubeissi, and Robert J. Maciunas

CA1 field (closer to the subiculum) and the subiculum itself was actually transected. However, the inferior temporal gyrus, parahippocampal gyrus, fusiform gyrus, and the entorhinal cortex were preserved. Before MHT and after each transection, 1.5–11.8 minutes (8.3 ± 3.1 minutes) of intraoperative electrocorticography recordings were made. Unless otherwise noted, values are expressed as the mean ± SD throughout. Electroencephalography Depth Recordings: Temporal and Amplitude Relationship Manual Evaluation Propagation of Epileptiform Discharges Within

Restricted access

Yasuhiro Yonekawa, Hans-Georg Imhof, Ethan Taub, Marijan Curcic, Yasuhiko Kaku, Peter Roth, Heinz Gregor Wieser, and Peter Groscurth

cavernous angioma in the left parahippocampal gyrus. In this communication we describe our experience in using the SCTT approach to structures such as the posterior hippocampal formation and the PCA (P 2 and P 3 segments), which does not place these highly important functional areas at risk. Clinical Material and Methods Case Selection The SCTT approach was used in 16 patients who underwent surgery at the Department of Neurosurgery of Zurich University Hospital between September 1997 and May 2000. The clinical data are listed in Table 1 . There were seven