Reconstruction of Lateral Skull Base Defects with Radial Forearm Free Flaps: The Double-Layer Technique

Introduction The radial forearm flap has fallen out of favor in lateral skull base reconstruction in recent literature. However, especially when used in a double layer, a radial forearm may be able to provide the thickness of a large flap while taking advantage of the pliability for which the flap is renowned. Objective To report the results of the double-layer technique of radial forearm free flap reconstruction of lateral temporal bone defects. Design A retrospective chart review. Setting A tertiary care institution. Participants All consecutive patients who underwent lateral temporal bone resections and were reconstructed with free flaps from 2006 to 2012. Major Outcome Measures Flap success rate, complications, and rate of revision surgery. Results A total of 17 patients were identified with free flap reconstruction of the lateral skull base. Seven received reconstruction with a double-layer radial forearm flap. Reconstruction-related complications in this group included one case of facial cellulitis. The flap success rate was 100%. These results were comparable with patients who had other flaps. Conclusions The radial forearm free flap may be an effective reconstruction option for lateral temporal bone defects especially when used in the double-layer technique.     

Saccade direction encoding in the primate entorhinal cortex during visual exploration

We recently demonstrated that position in visual space is represented by grid cells in the primate entorhinal cortex (EC), suggesting that visual exploration of complex scenes in primates may employ signaling mechanisms similar to those used during exploration of physical space via movement in rodents. Here, we describe a group of saccade direction (SD) cells that encode eye movement information in the monkey EC during free-viewing of complex images. Significant saccade direction encoding was found in 20% of the cells recorded in the posterior EC. SD cells were generally broadly tuned and two largely separate populations of SD cells encoded future and previous saccade direction. Some properties of these cells resemble those of head-direction cells in rodent EC, suggesting that the same neural circuitry may be capable of performing homologous spatial computations under different exploratory contexts.In visual exploration, the direction of saccadic eye movements carries important information about past and future gaze location. This information might be useful for optimal exploration of visual scenes and for memory processes that use information about spatial relationships. Encoding through ensembles of grid cells that represent gaze location (1) and saccade direction (SD) cells that represent gaze movement could provide the spatial information necessary to associate visual content with relative locations in visual space. Grid cells may provide location information, whereas SD cells may provide information about the relative ordering in space of viewed parts of the scene.In rodents, head-direction cells have been defined as cells with an allocentric heading preference when the animal is within a particular environment (2). Identified first in the postsubiculum (3) and then in the thalamus (4, 5) and the entorhinal cortex (EC) (6), head-direction cells are considered an essential component of the rodent spatial navigation system. In primates, we are aware of one report of four head-direction cells identified in the macaque presubiculum (7) and two reports of activity in the human EC related to the direction of virtual movement (8, 9). Many studies have examined neuronal responses related to eye movement direction signals in head-fixed monkeys, most often with saccades to a limited number of locations (10, 11), and recently in more natural contexts (12). However, directional encoding has remained largely unexamined in primate medial temporal lobe structures, and the relationship between neuronal activity and saccade direction in the EC has not previously been examined in a free-viewing exploratory context. Because we recently identified spatial signals in the primate EC during visual exploration (i.e., visual border cells and grid cells), we reasoned that saccadic eye movement trajectories in primates might also be represented in the EC.     

Melatonin protects testes against lithium‐pilocarpine‐induced temporal lobe epilepsy in rats: a time course study

Male dysfunction is common in patients with temporal lobe epilepsy (TLE). We evaluated whether melatonin, as a supplement, can play a positive role in reducing the epileptogenesis imposing abnormalities of spermatozoa and testes in epileptic rats. Status epilepticus was induced based on the TLE lithium‐pilocarpine model. Two patterns of melatonin were administered to the epileptic animals along the mean durations of latent (14 days) and chronic (60 days) phases. Sperm parameters, different antioxidant enzyme levels, germ cell apoptosis, body and relative sex organ weights were evaluated in all groups 60 days following SE induction. Chronic TLE caused a significant reduction in sperm parameters. In the testis, the reduced level of antioxidant enzymes was accompanied by a significant increase in malondialdehyde concentration. The presence of oxidant condition in the testes of epileptic animals caused expanded apoptosis in the germ cell layer. Moreover, the amount of weight gain in epileptic animals was more prominent. Melatonin administration was able to improve sperm motility by increasing the total antioxidant level. There was also a significant reduction in the spermatogenic cell line apoptosis and the extra weight gain of melatonin‐treated animals. Melatonin supplementation might be considered as an acceptable cotreatment in epileptic patients.     

Surgical management of persistent post-traumatic trans-tentorial brain hernia

IntroductionTemporal engagement may persist after etiologic surgical treatment of acute subdural hematoma (ASH) without clinical improvement despite normalized intracranial pressure (ICP). The aim of this study was to assess the feasibility of secondary direct temporal lobe disengagement (DTLD) after surgery for supratentorial ASH and to evaluate clinical outcome.Materials and methodsThis was a retrospective analysis of 4 patients undergoing secondary DTLD. Patient data were recorded at admission, pre- and postoperatively and at 6 months’ follow-up (FU): age, gender, Rotterdam score, Glasgow Coma Scale (GCS), neurological deficits, oculomotor nerve palsy (ONP), ICP, midline shift, complications and Extended Glasgow Outcome Scale (GOS-E).ResultsAt postoperative evaluation 48 h after DTLD, we observed a significant improvement in GCS score (initial 6 ± 3, preoperative 7 ± 3, postoperative 14 ± 1; P = 0.02), midline shift (initial 16 ± 3 mm, preoperative 13 ± 5 mm, postoperative 9 ± 2 mm; P = 0.049) and ONP (P = 0.01). In all cases, early postoperative imaging documented visualization of a patent ipsilateral peri-mesencephalic cistern. At 6-month FU, GOS-E showed 75% good recovery and 25% disability. Complete ONP recovery was observed in 75% of patients (P = 0.01). Neurological deficits were present at FU in 25% of patients. No surgery-related complications or mortality were recorded.ConclusionsIn traumatic brain injury, secondary DTLD may allow simple, effective and safe management of trans-tentorial uncal herniation, avoiding more challenging procedures. Clinical results are promising, as this technique seems to favorably influence neurological outcome in this selected subgroup of patients with persistent clinical and radiological signs of temporal engagement after etiological treatment with normal ICP values.     

基于MRI自动化定量海马体积诊断颞叶癫痫患者海马硬化

目的 评估基于MRI自动化定量海马体积诊断颞叶癫痫患者海马硬化（HS）的效能。方法 回顾性分析经术后病理检查证实的64例存在HS的颞叶癫痫患者,采用AccuBrain软件对头部3D T1WI进行自动化定量分析,检测海马体积指数（HVI）;以病理结果为诊断金标准,统计2名医师目测诊断HS结果。采用受试者工作特征（ROC）曲线获得HVI诊断HS的截断值及曲线下面积（AUC）,计算HVI诊断HS的敏感度、特异度和准确率,评价2种诊断方式所获结果的一致性。结果 64例中,38例左侧HS、26例右侧HS。医师目测诊断HS的敏感度、特异度、准确率分别为90.63%（58/64）、100%（64/64）及95.31%（122/128）。ROC曲线结果显示,HVI诊断HS的最佳截断值为0.185,AUC为0.936。HVI诊断HS的敏感度、特异度、准确率分别为87.50%（56/64）、93.75%（60/64）及90.63%（116/128）。医师目测与HVI诊断HS的准确率一致性较强（Kappa=0.684,P<0.05）。结论 MRI自动化定量海马体积可用于诊断颞叶癫痫患者HS,其诊断效能较高。