Analytical evaluation of complex anterior approaches to the cranial base: an anatomic study

OBJECTIVE: The purpose of the present study was to evaluate the anatomic areas of the cranial base exposed by different complex anterior approaches. METHODS: Using 20 embalmed cadaveric heads, we executed five different anterior approaches, i.e., Le Fort 1 approach with splitting or down-fracturing of the hard palate, extended maxillectomy, median mandibulotomy with glossotomy, and mandibular swing transcervical approach. Each approach was performed a minimum of three times. The areas of the intra- and extracranial cranial base exposed by each approach were analytically examined by using a numerical grading system to assess the exposure of major anatomic and neurovascular structures. RESULTS: Good exposure of the midline compartment of the cranial base was provided by the median mandibulotomy with glossotomy and by the Le Fort 1 approach with splitting of the hard palate, whereas the mandibular swing transcervical and extended maxillectomy approaches provided good exposure of the lateral compartment of the cranial base. CONCLUSION: Use of the numerical grading system allowed quantification of the exposure afforded by each approach, with respect to the different compartments (midline and lateral) of the intra- and extracranial cranial base, highlighting the differences among the approaches examined.     

En bloc resection of the temporal bone for middle ear carcinoma extending to the cranial base

En bloc resection of the temporal bone for squamous cell carcinoma of the middle ear was performed by the postauricular transtemporal and retromastoid approaches. The patient was a 70-year-old woman whose tumor extended to the middle and posterior cranial fossae. Temporal and retromastoid craniotomies were carried out, then the temporal dura and the cerebellar dura, and the transverse and sigmoid sinuses were exposed. The temporal dura and the cerebellar dura were opened, and the transverse sinus was ligated at the junction with the sigmoid sinus. After that, the tentorial dura was incised, the incision extending anteriorly to the middle cranial fossa and transecting the superior petrosal sinus. Consequently, a wide view into the middle and the posterior cranial fossae was obtained. In the posterior fossa, cranial nerves VII and VIII were divided. On the other hand, nerves IX, X and XI were preserved at the dural incision on the posterior surface of the temporal bone. Subsequently, in the area of the carotid canal, the temporal bone was drilled toward the medial side of the internal auditory canal and also posteriorly down to the jugular bulb. At this stage, the temporal bone and the soft tissue attachments, such as the middle and posterior cranial fossa dura, and the sigmoid sinus, were separated from the pyramidal apex and the clivus. The dural defect was repaired with a free pericranial graft. A rectus abdominis muscle flap was transferred to reconstruct the defect of the skull base resulting from the temporal bone resection. Postoperative complications like CSF leakage, meningitis and lower cranial nerve damage, were not seen after the treatment. The patient has shown no evidence of recurrence for the 28 months since the surgical treatment, and has not complained of any problems with swallowing or conducting conversations in daily life. With the contribution of recent developments in skull base and reconstruction surgery, more aggressive en bloc resection of the temporal bone can be carried out on patients with advanced middle ear carcinoma. These developments will also make it possible for patients whose prognosis was previously thought to be poor to have a chance for a cure.     

Relationship between anatomic lesions of the temporal lobe and temporal lobe epilepsy

A structural lesion of the brain is a frequent finding in intractable partial epileptic patients. We analyse anatomo-electro-clinical characteristics of 58 patients in which MR showed a lesion inside the temporal lobe. They are 29 males and 29 females with a mean age at surgery of 23.5 +/- 10.7 years (2.6-45.9). The mean epilepsy duration is of 13.4 +/- 8 years (1.3-35.5), with a mean seizure frequency of 28.7 +/- 43.6 per month, with a great inter-individual variability (from 3 per month to 15 a day). The minimum follow-up is 3.5 years. A video-EEG monitoring was performed in 21 cases, while a stereo-EEG investigation was judged mandatory in 26. On the basis of anatomo-electro-clinical correlations and of the results of presurgical investigations, the epileptogenic area was proved to be temporal in 49 cases, temporal but controlateral to the lesion in 1, and at least bilobar in 8 patients.     

Surgical anatomy of the temporal lobe

The complex functional and anatomic relationships between the structures in and around the temporal lobe are central to the problem of intractable partial complex seizures. Resecting those areas that are responsible for seizures and protecting those that are essential for the normal functioning of the patient are the fundamental tasks of the epilepsy surgeon. A thorough understanding of the structural and functional anatomy of this region is essential to achieve these goals.     

Memory and imagery in the temporal lobe

Experimental and clinical studies in primates indicate that visual information is stored and retrieved by interactions between the temporal association area and the medial temporal lobe structures. Recent findings from single-neuron recordings have provided new evidence that perceptual aspects of the temporal neocortex are closely related to its memory function based on association. They further suggest that imagery is also implemented by the same neural mechanism that subserves memory retrieval.     

Reconstruction of upper cranial and cranial base defects utilizing the scalping flap

Reconstruction of midfacial defects by means of a scalping flap has been widely practiced and described in the literature. The advantages of the flap are familiar to surgeons who perform extirpations and reconstruction of the head and neck and include contiguous availability, simplicity of application, and a robust and redundant blood supply. Despite these merits, the flap has not been widely used for reconstructions of large anterior cranial defects or defects of the cranial base. A retrospective review of 11 patients who underwent reconstructions between 1990 and 1995 was performed. In each case, a reconstruction of a large anterior cranial or cranial base defect was carried out. The resulting soft-tissue defect was restored via the scalping flap. In six cases, this was carried out in a single procedure. In five cases, flap division and insetting were carried out in a subsequent procedure, following a 1- to 2-week delay. In all cases, the extirpation and reconstruction were well tolerated, and the average time of hospitalization was 5.9 days and ranged from 3 to 11 days. No major surgical complications occurred. One of 11 patients had a minor complication not requiring surgical intervention. There was one recurrence of a cranial base tumor approximately 2 years following the initial resection and reconstruction. In all cases, the final aesthetic and functional results were acceptable to excellent. Follow-up ranged from 11 months to 5 years. In conclusion, the scalping flap can be effectively utilized for soft-tissue coverage in the reconstruction of anterior cranial and cranial base defects. Use of this simple and versatile flap in craniofacial reconstruction is well tolerated and is associated with a low morbidity, a good aesthetic result, and a short hospital stay.     

Effects of annular cranial vault modification on the cranial base and face

Artificial modification of the cranial vault was practiced by a number of prehistoric and protohistoric populations, frequently during an infant's first year of life. We test the hypothesis that, in addition to its direct effects on the cranial vault, annular cranial vault modification has a significant indirect effect on cranial base and facial morphology. Two skeletal series from the Pacific Northwest Coast, which include both nonmodified and modified crania, were used: the Kwakiutl (62 nonmodified, 45 modified) and Nootka (28 nonmodified, 20 modified). Three-dimensional coordinates of 53 landmarks were obtained using a diagraph, and 36 landmarks were used to define nine finite elements in the cranial vault, cranial base, and face. Finite element scaling was used to compare average nonmodified and average modified crania, and the significance of the results were evaluated using a bootstrap test. Annular modification of the cranial vault produces significant effects on the morphology of the cranial base and face. Annular modification in the Kwakiutl resulted in restrictions of the cranial vault in the medial-lateral and superior-inferior dimensions and an increase in anterior-posterior growth. Similar dimensional changes are observed in the cranial base. The Kwakiutl face is increased anterior-posteriorly and reduced anterior-laterally to posterior-medially. Similar effects of modification are observed in the Nootka cranial vault and cranial base, though not in the face. These results demonstrate the developmental interdependence of the cranial vault, cranial base, and face.     

Dynamics of the paroxysmal syndrome in temporal lobe epilepsy

Results of studying the time course of the paroxysmal syndrome based on long-term follow-up of 151 patients with temporal epilepsy are presented. Some regularities of the syndrome course are determined, a rather high degree of the variability of its manifestations over the period of the disease is established, a relative constancy of the aura, transformations of which were noted only in half of the observations, is shown. It is noted that the paroxysmal syndrome is the most developed within a period of 5 to 15 years after the disease onset. Results of conservative therapy are evaluated.     

Does naming contribute to memory self-report in temporal lobe epilepsy?

The present study evaluated the hypothesis (Mayeux et al., 1980) that visual confrontation naming deficits may underlie the memory complaint in patients with temporal lobe epilepsy (TLE). Thirty-nine patients with medically refractory left (n = 23) and right (n = 16) TLE were compared with an epilepsy control group with idiopathic primary generalized epilepsy (n = 38). All subjects completed selected subtests of the Multilingual Aphasia Examination and Wechsler Memory Scale (Form 1) together with a measure specifically designed for quantification of the memory complaint in TLE. Objective verbal memory test performance, confrontation naming, repetition, and comprehension were unrelated to memory self-report. Controlled Oral Word Association was the only measure to exert an influence on memory self-ratings, and this relationship was specific to the TLE group. The hypothesis of Mayeux et al. (1980) was not specifically supported, but the present findings do suggest that cognitive processes reflected in orthographically based and internally generated word retrieval play a role in memory self-report.     

Medial temporal lobe atrophy in stroke patients: relation to pre-existing dementia

BACKGROUND: To investigate the role and impact of multiplane transesophageal echocardiography during thrombectomy in the inferior vena cava or the right atrium. EXPERIMENTAL DESIGN: Retrospective. SETTING: A university hospital. PARTICIPANTS: Four patients who underwent removal of tumor thrombus in the inferior vena cava (IVC) or the right atrium. INTERVENTIONS: The medical records of 4 patients and videotapes of these intraoperative transesophageal echocardiography examinations were reviewed. RESULTS: Before thrombectomy, multiplane transesophageal echocardiography (MTEE) provided excellent IVC long axis view, which offered precise recognition of the cephalic extent of tumor, extent of caval occlusion, characterization of the tumor head. During surgery, MTEE could provide continuous monitoring of cardiac function, cardiac volume, and pulmonary embolism. Moreover, MTEE could provide the useful images of a cannula or the caval occlusion balloon catheter, which facilitated removal of neoplasm extending into the IVC. CONCLUSIONS: We presented four surgical cases, in which the removal of the tumor extended into the inferior vena cava or the right atrium using MTEE. MTEE could provide valuable information such as excellent images of the tumor, cardiac function, the position of a cannula or the caval occlusion balloon catheter. These findings could improve the anesthetic management of the patients, as well as the surgical approach and technical maneuvers, and facilitate removal of neoplasm into the IVC.     

Content-specific source encoding in the human medial temporal lobe.

Although the medial temporal lobe (MTL) is known to be essential for episodic encoding, the contributions of individual MTL subregions remain unclear. Data from recognition memory studies have provided evidence that the hippocampus supports relational encoding important for later episodic recollection, whereas the perirhinal cortex has been linked with encoding that supports later item familiarity. However, extant data also strongly implicate the perirhinal cortex in object processing and encoding, suggesting that perirhinal processes may contribute to later episodic recollection of object source details. To investigate this possibility, encoding activation in MTL subregions was analyzed on the basis of subsequent memory outcome while participants processed novel scenes paired with 1 of 6 repeating objects. Specifically, encoding activation correlating with later successful scene recognition memory was evaluated against that of source recollection for the object paired with the scene during encoding. In contrast to studies reporting a link between perirhinal cortex and item familiarity, it was found that encoding activation in the right perirhinal cortex correlates with successful recollection of the paired object. Furthermore, other MTL subregions also exhibited content-specific source encoding patterns of activation, suggesting that MTL subsequent memory effects are sensitive to stimulus category. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alumina gel injections into the temporal lobe of rhesus monkeys cause complex partial seizures and morphological changes found in human temporal lobe epilepsy

The goal of the present study was to determine whether alumina gel injections into temporal lobe structures cause complex partial seizures (CPS) and pathological changes observed in human temporal lobe epilepsy. Rhesus monkeys with alumina gel injections in the amygdala, perirhinal and entorhinal cortices, or Ammon's horn and dentate gyrus all initially displayed focal pathological electroencephalographic (EEG) slowing limited to the site of injection. After clinical seizures developed, they also displayed widespread pathological EEG slowing over both hemispheres, interictal and ictal epileptiform EEG abnormalities limited to the mesial-inferior temporal lobe on the side of injection, and different degrees of spread to other ipsilateral and contralateral structures. Noninjected control and nonepileptic monkeys with injections into the middle and inferior temporal gyri displayed no hippocampal neuronal loss or mossy fiber sprouting. When alumina gel was injected into the amygdala, CPS began within 3-6 weeks and degeneration of neurons and gliosis occurred in the perirhinal cortex or the hippocampus, with consequent sprouting of mossy fibers in the dentate gyrus. Dispersion of the granule cell layer was also observed. Other monkeys with alumina gel in the perirhinal and entorhinal cortices developed CPS within 2-3 weeks after the injections and displayed mossy fiber sprouting only after 4 weeks after the injections. Alumina gel in Ammon's horn and the dentate gyrus also induced CPS, but mossy fiber sprouting was limited to sites immediately adjacent to the injection, probably because none survived more than 4 weeks after the injections. This nonhuman primate model of CPS displayed similar anatomical, behavioral, and EEG features as observed in human temporal lobe epilepsy and provides opportunities to analyze the chronological sequence of epileptogenesis and to test potential therapies.     

Transverse glabellar flap for obliteration/isolation of the nasofrontal duct from the anterior cranial base

Management of fractures involving the nasofrontal duct region of the frontal sinus has focused on preserving function when possible or obliterating the sinus and duct when fracture patterns potentiate ductal obstruction and possible transcranial seeding of bacteria. When frontal sinus preservation is in doubt, controversy surrounds the use of cranialization versus obliteration, and the method of obliteration. Perioperative and late postoperative infections are uncommon, but their occurrence jeopardizes an often complex reconstruction and can be life threatening. This paper describes the design and indications for a pedicled transverse glabellar muscle flap for obliteration of the nasofrontal duct, thereby isolating the anterior cranial base from the aerodigestive system. This vascularized muscle flap utilizes the corrugator supercilii and procerus muscles, which are introduced into the sinus via a small, surgically created window in the superomedial orbital wall without disturbing the central facial aesthetic contours. Six patients with comminuted fractures at the nasofrontal duct level associated with displaced posterior frontal sinus fractures have been treated with the transverse glabellar flap. Follow-up ranges from 8 to 30 months. There have been no early or late postoperative complications. The transverse glabellar flap is a reliable and versatile method of partitioning the upper aerodigestive tract from the anterior cranial base with vascularized tissue, thus minimizing the risk of infectious complications. The resulting donor site deformity is more acceptable than that seen with the traditional pedicled galeal frontalis flap.     

Functional MRI lateralization of memory in temporal lobe epilepsy

OBJECTIVE: To determine the feasibility of using functional magnetic resonance imaging (fMRI) to detect asymmetries in the lateralization of memory activation in patients with temporal lobe epilepsy (TLE). BACKGROUND: Assessment of mesial temporal lobe function is a critical aspect of the preoperative evaluation for epilepsy surgery, both for predicting postoperative memory deficits and for seizure lateralization. fMRI offers several potential advantages over the current gold standard, intracarotid amobarbital testing (IAT). fMRI has already been successfully applied to language lateralization in TLE. METHODS: fMRI was carried out in eight normal subjects and 10 consecutively recruited patients with TLE undergoing preoperative evaluation for epilepsy surgery. A complex visual scene encoding task known to activate mesial temporal structures was used during fMRI. Asymmetry ratios for mesial temporal activation were calculated, using regions of interest defined in normals. Patient findings were compared with the results of IAT performed as part of routine clinical evaluation. RESULTS: Task activation was nearly symmetric in normal subjects, whereas in patients with TLE, significant asymmetries were observed. In all nine patients in whom the IAT result was interpretable, memory asymmetry by fMRI concurred with the findings of IAT including two patients with paradoxical IAT memory lateralization ipsilateral to seizure focus. CONCLUSIONS: fMRI can be used to detect asymmetries in memory activation in patients with TLE. Because fMRI studies are noninvasive and provide excellent spatial resolution for functional activation, these preliminary results suggest a promising role for fMRI in improving the preoperative evaluation for epilepsy surgery.     

Quantitative analysis of interictal behavior in temporal lobe epilepsy

Patients with unilateral temporal epileptic foci were contrasted with normal subjects and patients with neuromuscular disorders in the evaluation of specific psychosocial aspects of behavior. Eighteen traits were assessed in equivalent questionnaires completed by both subjects and observers. The epileptic patients self-reported a distinctive profile of humorless sobriety, dependence, and obsessionalism; raters discriminated temporal lobe epileptics on the basis of circumstantiality, philosophical interests, and anger. The right temporal epileptic displayed emotional tendencies in contrast to ideational traits of left temporal epileptic. Right temporal epileptics exhibited "denial," while left temporal epileptics demonstrated a "catastrophic" overemphasis of dissocial behavior. The results support the hypotheses that sensory-affective associations are established within the temporal lobes, and that, in man, there exists a hemispheric asymmetry in the expression of affect.     

Impaired perception of facial emotions following bilateral damage to the anterior temporal lobe.

Two patients (E.P. and G.T.) were previously described with damage to amygdala and anterior temporal cortex (S.B. Hamann et al., 1996). Both rated emotions in facial expressions normally (the rating task) when the data analysis followed a method that had revealed an impairment in the well-studied patient S.M. The present study reports findings for a 3rd patient (G.P.) with the rating task and reexamines the data for E.P. and G.T. All 3 patients were also given a labeling task in which they selected, from a list of 6 words, which word they thought best described the emotion expressed by a face. All 3 patients were unmistakably impaired on both tasks. However, the impairment exhibited by these patients is different from S.M.'s impairment. The difference may depend on the etiology (congenital vs. adult-onset lesion) or the site of the damage (relatively selective amygdala damage vs. damage to amygdala as well as anterior temporal cortex). (PsycINFO Database Record (c) 2010 APA, all rights reserved)