No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Approaches to temporal lobe lesions: A proposal for classification
Abstract
Tumor surgery in the temporal region is challenging due to anatomical complexity and the versatility of surgical approaches. The aim was to categorize temporal lobe tumors based on anatomical, functional, and vascular considerations and to devise a systematic field manual of surgical approaches.
Tumors were classified into four main types with assigned approaches: Type I-lateral: transcortical; type II-polar: pterional/transcortical; type III-central: transsylvian/trans-opercular; type IV-mesial: transsylvian/trans-cisternal if more anterior (=Type IV A), and supratentorial/infraoccipital if more posterior (=type IV B). 105 patients have been operated on prospectively using the advocated guidelines. Outcomes were evaluated.
Systematic application of the proposed classification facilitated a tailored approach, with gross total tumor resection of 88 %. Neurological and surgical morbidity were less than 10 %. The proposed classification may prove a valuable tool for surgical planning.
... Based on the results of their randomised trial, Lutz et al. [20] concluded that the trans-MTG approach provides better phonemic outcomes than the transsylvian approach, while cognitive outcomes and freedom from seizures were comparable between the two approaches. Based on their laboratory investigation, Bozkurt et al. [25] concluded that the trans-MTG approach may allow better visualisation of MTL structures than the transsylvian approach. Uda et al. [23] concluded that visual field deficits (83% vs. 60% respectively) and memory function were comparable between the trans-MTG approach and the transsylvian approach, with a shorter time of surgery for the trans-MTG approach. ...
... Uda et al. [23] concluded that visual field deficits (83% vs. 60% respectively) and memory function were comparable between the trans-MTG approach and the transsylvian approach, with a shorter time of surgery for the trans-MTG approach. The typical trans-MTG approach, apart from damaging the lateral temporal neocortex, puts at risk some crucial white matter tracts (WMTs), such as inferior frontooccipital fasciculus (IFOF) and Meyer's loop [24,25]. ...
... On the other hand, it has been suggested that the transsylvian approach may be more selective, allowing for less interruption of WMTs (especially optic radiation fibres) and preservation of the lateral temporal neocortex [25]. It is worth remembering that it has been found that the transsylvian Neurologia i Neurochirurgia Polska 2024 www.journals.viamedica.pl/neurologia_neurochirurgia_polska ...
... 11 Due to the unique morphology of the temporal lobe, which includes a long anterior to posterior distance, the temporal lobe can be divided into anterior and posterior parts using the widest point of the brainstem. 12,13 The temporal lobe can be further subdivided into lateral and medial parts, which affect the strategy and difficulty of glioma surgery. 12 As long as gliomas are located in the lateral temporal lobe, the anterior or posterior part does not matter for the approach to the superficial tumor. ...
... 12,13 The temporal lobe can be further subdivided into lateral and medial parts, which affect the strategy and difficulty of glioma surgery. 12 As long as gliomas are located in the lateral temporal lobe, the anterior or posterior part does not matter for the approach to the superficial tumor. In regard to gliomas located in the medial temporal lobe, known to be challenging tumors for surgery, 13,14 location in the anterior or posterior parts does matter. ...
... "Anterior" medial temporal tumors can be removed by the transsylvian approach, anterior two-thirds lobectomy, or temporal pole resection. 13 On the other hand, "posterior" medial temporal tumors have large variations in surgical approaches, such as the suboccipital approach, 12,15 subtemporal approach, 13 occipital interhemispheric approach, 3 supracerebellar transtentorial approach, 15,16 and transcortical approach. 13,17 The posterior medial temporal lobe comprises the posterior part of the parahippocampal gyrus. ...
Objective:
The parietooccipital fissure is an anatomical landmark that divides the temporal, occipital, and parietal lobes. More than 40% of gliomas are located in these three lobes, and the temporal lobe is the most common location. The parietooccipital fissure is located just posterior to the medial temporal lobe, but little is known about the clinical significance of this fissure in gliomas. The authors investigated the anatomical correlations between the parietooccipital fissure and posterior medial temporal gliomas to reveal the radiological features and unique invasion patterns of these gliomas.
Methods:
The authors retrospectively reviewed records of all posterior medial temporal glioma patients treated at their institutions and examined the parietooccipital fissure. To clarify how the surrounding structures were invaded in each case, the authors categorized tumor invasion as being toward the parietal lobe, occipital lobe, isthmus of the cingulate gyrus, insula/basal ganglia, or splenium of the corpus callosum. DSI Studio was used to visualize the fiber tractography running through the posterior medial temporal lobe.
Results:
Twenty-four patients with posterior medial temporal gliomas were identified. All patients presented with a parietooccipital fissure as an uninterrupted straight sulcus and as the posterior border of the tumor. Invasion direction was toward the parietal lobe in 13 patients, the occipital lobe in 4 patients, the isthmus of the cingulate gyrus in 19 patients, the insula/basal ganglia in 3 patients, and the splenium of the corpus callosum in 8 patients. Although the isthmus of the cingulate gyrus and the occipital lobe are located just posterior to the posterior medial temporal lobe, there was a significantly greater preponderance of invasion toward the isthmus of the cingulate gyrus than toward the occipital lobe (p = 0.00030, McNemar test). Based on Schramm's classification for the medial temporal tumors, 4 patients had type A and 20 patients had type D tumors. The parietooccipital fissure determined the posterior border of the tumors, resulting in a unique and identical radiological feature. Diffusion spectrum imaging (DSI) tractography indicated that the fibers running through the posterior medial temporal lobe toward the occipital lobe had to detour laterally around the bottom of the parietooccipital fissure.
Conclusions:
Posterior medial temporal gliomas present identical invasion patterns, resulting in unique radiological features that are strongly affected by the parietooccipital fissure. The parietooccipital fissure is a key anatomical landmark for understanding the complex infiltrating architecture of posterior medial temporal gliomas.
... Previously, we proposed and applied the division of temporal lobe tumors into 4 basic topographic types. 7 The division was based on the graded assembly of the temporal lobe from outer over intermediate to inner layers on axial sections, and thus reflected the ascending ontogenetic ages of the lobe from outer to inner layers. In that earlier study, we also demonstrated that a strict allocation of anatomical tumor location with a surgical approach-that is, lateral and polar tumor location with transcortical approaches and limbic and central/intrinsic tumor locations with transsylvian approaches-resulted in minimal neurological morbidity other than VFDs, including hemiparesis and aphasia, as well as minimal vascular complication and good gross-total resection. ...
... Our previous classification of approaches 7 was rather intuitive. We found that the applied approaches resulted in a maximum reduction of visual field deficits. ...
OBJECT
Visual field defects (VFDs) due to optic radiation (OR) injury are a common complication of temporal lobe surgery. The authors analyzed whether preoperative visualization of the optic tract would reduce this complication by influencing the surgeon’s decisions about surgical approaches. The authors also determined whether white matter shifts caused by temporal lobe tumors would follow predetermined patterns based on the tumor’s topography.
METHODS
One hundred thirteen patients with intraaxial tumors of the temporal lobe underwent preoperative diffusion tensor imaging (DTI) fiber tracking. In 54 of those patients, both pre- and postoperative VFDs were documented using computerized perimetry. Brainlab’s iPlan 2.5 navigation software was used for tumor reconstruction and fiber visualization after the fusion of DTI studies with their respective magnetization-prepared rapid gradient-echo (MP-RAGE) images. The tracking algorithm was as follows: minimum fiber length 100 mm, fractional anisotropy threshold 0.1. The lateral geniculate body and the calcarine cortex were employed as tract seeding points. Shifts of the OR caused by tumor were visualized in comparison with the fiber tracking of the patient’s healthy hemisphere.
RESULTS
Temporal tumors produced a dislocation of the OR but no apparent fiber destruction. The shift of white matter tracts followed fixed patterns dependent on tumor location: Temporolateral tumors resulted in a medial fiber shift, and thus a lateral transcortical approach is recommended. Temporopolar tumors led to a posterior shift, always including Meyer’s loop; therefore, a pterional transcortical approach is recommended. Temporomesial tumors produced a lateral and superior shift; thus, a transsylvian-transcisternal approach will result in maximum sparing of the fibers. Temporocentric tumors also induced a lateral fiber shift. For those tumors, a transsylvian-transopercular approach is recommended. Tumors of the fusiform gyrus generated a superior (and lateral) shift; consequently, a subtemporal approach is recommended to avoid white matter injury. In applying the approaches recommended above, new or worsened VFDs occurred in 4% of the patient cohort. Total neurological and surgical morbidity were less than 10%. In 90% of patients, gross-total resection was accomplished.
CONCLUSIONS
Preoperative visualization of the OR may help in avoiding postoperative VFDs.
... Critical assessment returned a low risk of bias for all included studies, rendering this review a low overall risk of bias [Supplementary File 1]. Table 1 [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][21][22][23][24][25][26][27][28][29][30][32][33][34][35][37][38][39][40][41][42][43][44][45][46][47][48][50][51][52][53][54][55][56][57] summarizes the demographics, pathology, and surgical anatomy of all 2604 pooled patients. Age ranged from 5 to 80 years, with a male prevalence of 57.78% [ Table 2]. ...
Background
Transcortical approaches, encompassing various surgical corridors, have been employed to treat an array of intraparenchymal or intraventricular brain pathologies, including tumors, vascular malformations, infections, intracerebral hematomas, and epileptic surgery. Designing cortical incisions relies on the lesion location and characteristics, knowledge of eloquent functional anatomy, and advanced imaging such as tractography. Despite their widespread use in neurosurgery, there is a noticeable lack of systematic studies examining their common lobe access points, associated complications, and prevalent pathologies. This scoping review assesses current evidence to guide the selection of transcortical approaches for treating a variety of intracranial pathologies.
Methods
A scoping review was conducted using the PRISMA-ScR guidelines, searching PubMed, EMBASE, Scopus, and Web of Science. Studies were included if ≥5 patients operated on using transcortical approaches, with reported data on clinical features, treatments, and outcomes. Data analysis and synthesis were performed.
Results
A total of 50 articles encompassing 2604 patients were included in the study. The most common primary pathology was brain tumors (60.6%), particularly gliomas (87.4%). The transcortical-transtemporal approach was the most frequently identified cortical approach (70.48%), and the temporal lobe was the most accessed brain lobe (55.68%). The postoperative course outcomes were reported as good (55.52%), poor (28.38%), and death (14.62%).
Conclusion
Transcortical approaches are crucial techniques for managing a wide range of intracranial lesions, with the transcortical-transtemporal approach being the most common. According to the current literature, the selective choice of cortical incision and surgical corridor based on the lesion’s pathology and anatomic-functional location correlates with acceptable functional outcomes.
PURPOSE
The limbic system is a collection of brain structures responsible for affective processing, spatial coding, and certain types of memory. A comprehensive investigation of numerous limbic system components is necessary to thoroughly understand anatomical and pathological differences in individuals with related disorders (e.g., Alzheimer’s, depression, etc.). This study examines anatomical variations of limbic system structures including the hippocampus, dentate gyrus, amygdala, and cingulate gyrus.
METHODS
This cadaveric study includes the dissection of 47 formalin-fixed brain hemispheres and measurements of pertinent structures. The dentate gyrus, hippocampus, and amygdala were given categorical results: ill-defined, moderately defined, and well-defined; additionally, quantitative measurements were taken for all structures.
RESULTS
Our results indicate variations in the classification of the dentate gyrus (36% well-defined, 51% moderately defined, and 13% ill-defined) and amygdala (58% well-defined, 40% moderately defined, and 2% ill-defined). All hippocampus samples were well-defined (100%).
CONCLUSION
The knowledge of typical anatomy and morphology furthers our understanding of the limbic system and could be used to better understand clinical presentations. Future studies may be able to link anatomical variations and any potential relationships reported in this study to observed behavior. In summary, a thorough understanding of these variations will be useful for diagnostic purposes and future research.
OBJECTIVE
The objective of this paper was to assess applications of the supratentorial-infraoccipital (STIO) approach for cerebrovascular neurosurgery.
METHODS
The authors conducted a cohort study of all consecutive cases in which the STIO approach was used during the study period, December 1995 to January 2021, as well as a systematic review of the literature.
RESULTS
Twenty-five cerebrovascular cases were identified in which the STIO approach was used. Diagnoses included arteriovenous malformation (n = 15), cerebral cavernous malformation (n = 5), arteriovenous fistula (n = 4), and aneurysm (n = 1). The arteriovenous malformations consisted of Spetzler-Martin grade II (n = 3), grade III (n = 8), and grade IV (n = 4) lesions. Lesion locations included the occipital lobe (n = 15), followed by the tentorial dural (n = 4), temporal-occipital (n = 3), temporal (n = 1), thalamic (n = 1), and quadrigeminal cistern (n = 1) regions. Many patients (75%) experienced transient visual deficits attributable to retraction of the occipital lobe, all of which resolved. As of last follow-up (n = 12), modified Rankin Scale scores had improved for 6 patients and were unchanged for 6 patients compared with the preoperative baseline.
CONCLUSIONS
The STIO approach is a safe and effective skull base approach that provides a specialized access corridor for appropriately selected cerebrovascular lesions.
Surgical treatment of lesions involving the postero-medial occipito-temporal region is challenging because of high risk of morbidity due to damage or excessive retraction of critical neuro-vascular structures, especially within the dominant hemisphere.1-3
Here, we describe the case of a 17-yr-old patient who underwent resection of an epileptogenic low-grade tumor located within the left-dominant lingual gyrus. Seizures were characterized, as a first symptom, by right-sided simple visual hallucination that pointed to the left pericalcarine region, corresponding to the lesion location. No signs of primary involvement of anterior temporo-mesial structures (hippocampus/amygdala) were found. As the anatomo-electroclinical correlation was concordant, direct tumor removal was indicated through an infra-occipital supratentorial approach.
This route allowed direct access to the target through a safe extra-axial corridor, which limits intraparenchymal dissection until the tumor margin is identified and avoids critical vascular structures, such as the vein of Labbé.4,5 An external cerebrospinal fluid (CSF) drainage was used to facilitate brain relaxation, minimizing brain and venous retraction and, consequently, reducing the risk of postoperative neurological complications, especially for vision. Postoperative magnetic resonance imaging (MRI) demonstrated no surgical complications. Pathological examination revealed a ganglioglioma. At 9-mo follow-up, the neurological examination was normal, antiepileptic therapy was stopped, and the patient was seizure-free.
The video describes the main surgical steps, using both intraoperative videos and advanced 3-dimensional modeling of neuroimaging pictures.
Informed consent was obtained for surgery and video recording.
Objective:
Maximal safe resection prolongs the survival of patients with glioblastoma (GB). However, whether total resection of the enhanced lesion is pursued or abandoned depends on preoperative judgments based on the findings of magnetic resonance imaging (MRI). Anatomically, medial temporal tumor tends to invade toward the temporal stem, insula, and basal ganglia, representing tumor with high surgical risk. In the present study, we describe the key radiologic features of medial temporal GB to achieve extent of resection.
Methods:
We reviewed all GB cases located in the temporal lobe (tGB) treated between April 2013 and March 2018 at Kitasato University Hospital. On the basis of MRI, tGB was simply classified into 3 groups: medial tGB and nonmedial tGB, and medial tGB was further subdivided into invading type and mimicking type. We focused on the resectability of medial tGB.
Results:
Twenty-seven patients with tGB were identified. Twenty were included in the nonmedial tGB, and 7 were in the medial tGB. All medial tGB seemed to invade into the basal ganglia and/or the lenticulostriate arteries, but detailed examination revealed 2 types of tumor, invading type (3 cases) and mimicking type (4 cases). The invading type had true involvement of the basal ganglia and/or lenticulostriate arteries, whereas the mimicking type had no involvement of these structures. This new classification is highly effective, as the former is unresectable, but the latter is totally resectable.
Conclusions:
Medial tGB is a challenging tumor for maximal safe resection, so our classification will help to identify cases of removable medial tGB.
Temporomesiale Tumore sind limbischen Ursprungs und damit zunächst beschränkt auf das limbische System mit Hippokampus und Parahippokampus, Areale mit allo- oder mesokortikaler Architektur sowie die Amygdala. Häufige Symptome sind epileptische Anfälle, bei niedriggradigen Tumoren oder Fehlbildungstumoren auch langjährige medikamentös therapierefraktäre Epilepsien. Neuropsychologische Beeinträchtigungen sind häufiger als sonstige fokale Defizite, postoperativ sind Gesichtsfelddefekte typisch. Noch bis in die 2000er Jahre galt die temporomediale Tumorlokalisation häufig als inoperabel. Die operative Therapie ist anspruchsvoll, moderne operative Zugänge hängen von der temporomedialen Lage und Ausdehnung des Tumors ab. Ziel einer Operation ist, wenn bei vertretbarem Risiko möglich, die vollständige, aber funktionserhaltende Resektion.
The use of the supratentorial-infraoccipital approach is reported in seven patients with posteromedial temporal lobe lesions. No patient had permanent morbidity. Gross total resection of three low-grade gliomas and two gangliogliomas was achieved in five patients; one patient had subtotal resection of a low-grade glioma with adjacent gliosis, and one was initially thought to have a glioma but proved to have encephalomalacia on final pathological analysis. The patients ranged in age from 5 to 34 years. All seven patients presented with seizures, and four had uncontrolled seizures preoperatively. Six have been seizure-free since surgery (mean follow-up period 15 months), and one is well controlled on anticonvulsant medication. An anatomical study was performed to delineate the microsurgical anatomy relevant to operating on the medial temporal lobe through this posterior approach. A viewing wand intraoperative navigational system was utilized with this approach and proved helpful in gaining access as far anterior as the uncus through this occipital craniotomy. This approach is favorable in selected patients with posterior, medial, temporal lobe tumors because resection of otherwise difficult lesions may be accomplished without sacrificing lateral temporal lobe cortex or transecting the optic radiations.
The authors evaluated operative, neuropathological, and neuropsychological results after selective subtemporal amygdalohippocampectomy for refractory temporal lobe epilepsy in patients who were observed for at least 2 years after surgery.
Twenty-six consecutive patients underwent selective subtemporal amygdalohippocampectomy for nonlesional, medically refractory temporal lobe epilepsy. Neuropsychological evaluation using the Wechsler Adult Intelligence Scale was done before surgery in all patients, 2 months after surgery in 24 patients, and at 2-year follow up in 19 patients. A verbal paired associates learning test was administered before surgery and 2 months after surgery in 19 patients. The data were compared between the 13 patients in whom the language-dominant hemisphere was surgically treated and the six patients in whom the language-nondominant hemisphere was treated. After surgery, 84% of the patients attained either Engel Class I or II seizure outcome. There were no permanent subjective complications except postoperative memory impairment in one patient. Neuropathological examination confirmed hippocampal sclerosis in 19 patients. No significant differences in IQ and verbal memory test scores were observed between the patients in whom the language-dominant hemisphere was treated and those in whom the language-nondominant hemisphere was treated. Significant postoperative increases in verbal IQ, performance IQ, and full-scale IQ were observed over time. No significant differences were found between pre- and postoperative verbal memory test scores, and no subjective visual field loss was marked in any patient.
Subtemporal selective amygdalohippocampectomy provides favorable surgical and neuropsychological outcomes and does not cause significant postoperative decline of verbal memory if performed on the language-dominant side.
In this retrospective review, the authors examine the clinical characteristics, diagnosis, and outcome of surgery in 25 consecutive patients with mesial basal temporal lobe (MBTL) tumors. A limited access approach to the inferior temporal gyrus (ITG) was used.
Patients with MBTL tumors were identified from the epilepsy and tumor surgery database at the authors' institution. Intraaxial tumors localized to the mesial basal structures, and without involvement of the cortical surface of the temporal lobe, temporal stem, and basal ganglia were included. Preoperative and postoperative MR images were obtained in all patients. The mean follow-up period was 24 months (range 9-36 months). Preoperative symptoms, neurological deficits, outcomes, surgical complications, and a technical description of the approach are discussed.
Intraaxial MBTL tumors in 25 patients (mean age 44 years, range 8-76 years) were resected using a limited access approach via the ITG. The largest groups of tumors were high-grade gliomas and dysembryoblastic neuroepithelial tumors (8 in each group), followed by oligodendrogliomas, cerebral metastases, and gangliogliomas. Seizures, headaches, and disorientation were the most common preoperative symptoms. Postoperative MR images demonstrated gross-total resection in all cases. There were 2 surgical complications (a superficial wound infection and a transient frontalis branch palsy). There were no permanent neurological complications or significant new hemianoptic defects.
A limited access ITG approach performed with intraoperative image guidance offers an alternative corridor for resection of MBTL tumors (Schramm Type A). This approach may be technically less demanding than the transsylvian or subtemporal approach. Gross-total resection is feasible utilizing this approach and compares favorably with other, more classical approaches.
The most common surgical procedure for the mesial temporal lobe is the standard anterior temporal resection or what is commonly called the anterior temporal lobectomy. There are, however, a number of other more selective procedures for removal of the mesial temporal lobe structures (amygdala, hippocampus, and parahippocampal gyrus) that spare much of the lateral temporal neocortex. Included in these procedures collectively referred to as selective amygdalohippocampectomy are the transsylvian, subtemporal, and transcortical (trans-middle temporal gyrus) selective amygdalohippocampectomy. In this manuscript the author reviews some of the surgical details of the trans-middle temporal gyrus approach to the mesial temporal structures.
Development of a classification for temporal mediobasal tumors based on anatomical and neuroradiological aspects to help evaluate surgical accessibility and risk.
Preoperative magnetic resonance imaging, surgical approaches and outcomes of 235 patients with a temporal mediobasal tumor were analyzed retrospectively. Surgical landmarks were defined in accordance with operative anatomy. Previous classifications of these tumors were reviewed and a new classification system was developed.
The new classification system recognises four types of temporal mediobasal tumor based on anatomical landmarks, location, and size. Type A comprises lesions confined to the uncus, hippocampus, parahippocampus, and/or amygdala. Type B comprises lesions in the area immediately lateral to the structures where type A tumors are located but sparing lateral gyri. Type C tumors are larger lesions, which occupy the area of type A and type B simultaneously. Type D tumors originate from the temporal mediobasal region and invade into the adjacent structures of the temporal stem, insular cortex, claustrum, putamen, or pallidum. The area occupied by a tumor in the axial plane was divided into anterior (a) and posterior (p) subregions. Progressive grading from A to D and from "a" to "p" was based on the view that larger and more posteriorly growing tumors were more difficult to remove. Lesions located in the anterior subregion (n = 173) were easier to remove by the transsylvian route (39%) or after partial anterior lobectomy (32%). For the posterior lesions (n = 62), a subtemporal approach was more appropriate (75%).
Based on a series of 235 temporal mediobasal tumors, a classification system was designed to aid in decision making about operability, surgical risk, and approach.
An attempt was made to transect the white matter that connects the anterior temporal lobe with dorsal and medial brain areas.
Eight monkeys were trained preoperatively on a visual discrimination and tested postoperatively for retention and relearning
of the task. They were also tested for Kluver-Bucy symptoms. The two animals that had complete lesions were unable to relearn
the visual discrimination. It is suggested that human medial temporal lesions may produce their effects on learning and retention
by damage to temporal white matter rather than by destruction of hippocampus.
The development in Zurich of selective amygdalo-hippocampectomy as a means of treating certain forms of epilepsy which were not necessarily related to gross structural lesions came about as a result of two main influences.
We report indications and techniques as well as preliminary results of a new microsurgical method of treatment for patients with drug-resistant psychomotor epilepsy in whom mesiobasal temporal lobe epilepsy has been diagnosed. The most important reason for surgical intervention in our series of 27 patients was their epilepsy. In 12 patients a tumor of the amygdala and/or hippocampal formation was suspected or had been proved. In 13 patients the amygdala and/or hippocampus had been delineated as the epileptogenic area by long-term monitored stereo-electroencephalography. In the remaining 2 patients, clear-cut ictal findings on surface electroencephalography allowed operation. Preliminary results of this selective surgical procedure are very promising. They indicate that this type of psychomotor epilepsy can be treated more successfully in ths new way than by the classic removal of the temporal lobe or by stereotactic methods. After 6 to 73 months of follow-up (mean = 21), 22 patients were free of seizures. The postoperative neuropsychological follow-up studies showed better results than those for patients who underwent large temporal lobe resections. In more than half of the patients a clear-cut general improvement in tests of intellectual performance was found. Learning and memory impairments were also much less pronounced or even undetectable.
The authors propose a novel surgical approach for amygdalohippocampectomy (AH) in patients with temporal lobe epilepsy. Via a transsylvian-transcisternal route, the parahippocampal gyrus is directly exposed from its medial aspect, thus allowing a standardized en bloc resection of the temporomesial epileptogenic structures--the amygdala, anterior hippocampus, parahippocampal gyrus, and subiculum. Additional anatomical studies have been performed for standardization of this approach.
From 1990 to 1996, 32 patients presenting with medically intractable mesial temporal lobe epilepsy underwent AH via the transsylvian-transcisternal approach. Preoperative computerized tomography and magnetic resonance imaging revealed temporomesial lesions in 16 patients. Histopathological examination revealed cavernous malformations in seven patients, low-grade astrocytomas in four, hamartomas in three, and gangliogliomas in two patients. Specimens obtained in patients with no lesions were diagnosed as hippocampal sclerosis in all cases. No patient experienced permanent morbidity. Nine percent of the patients developed a temporary partial oculomotor nerve palsy. Only one patient developed a postoperative visual field deficit with a contralateral quadrantanopsia. With respect to seizure outcome, all patients benefited from surgery. At follow-up evaluation (mean 26.4 months), 80% of the patients were free from seizures (Engel Class I). Eight patients in this group were no longer receiving medication. Seventeen percent had experienced only one to several seizures since surgery (Engel Class II) and 3% reported a worthwhile improvement (Engel Class III).
In contrast to previously described standard techniques for AH, the transsylvian-transcisternal approach presented in this study offers improved anatomical orientation and intraoperative control over the mesial temporal lobe and preserves the lateral as well as the laterobasal temporal lobe.
Numerous studies of the electrophysiology and neuropathology of temporal lobe epilepsy have demonstrated the mesial temporal structures to be the site of seizure origin in the majority of cases. This is the rationale for a transcortical selective approach, first introduced by Niemeyer, for removal of the hippocampus and amygdala. Series from a number of centers have demonstrated the efficacy of selective amygdalohippocampectomy compared to a more traditional resection. The technique described here and used at the Montreal Neurological Institute (MNI) utilizes a strictly endopial resection of the hippocampal formation and amygdala in addition to computer image guidance to perform the procedure. Ninety-five percent of patients at the MNI who underwent selective amygdalohippocampectomy realized a cessation of seizures, or greater than 90% reduction, with minimal risk of complications.
An intraventricular glioma occupying all four ventricles of the brain in children is very uncommon. The authors report a unique case of a tetraventricular Grade II astrocytoma with evidence of extension into the basal cisterns in a 5-year-old boy who had a 1-month history of headache. There was no neurological deficit except bilateral papilledema.
Selective amygdalohippocampectomy as surgical treatment of mesiobasal limbic epilepsy
- Wieser Hg
- Mg
Wieser HG, Yaşargil MG (1982) Selective amygdalohippocampectomy as surgical treatment of mesiobasal limbic epilepsy. Surg Neurol 17:445– 457
Augustenburger Platz 1, 13353 Berlin, Germany e-mail: peter.vajkoczy@charite.de P. Schmiedek Department of Neurosurgery
- K Faust
K. Faust : P. Vajkoczy (*) Department of Neurosurgery, Charité University Hospital, Augustenburger Platz 1, 13353 Berlin, Germany e-mail: peter.vajkoczy@charite.de P. Schmiedek Department of Neurosurgery, University Hospital, Medical Faculty of University Heidelberg, Mannheim, Germany Acta Neurochir (2014) 156:409–413 DOI 10.1007/s00701-013-1917-4 References