术中皮质体感诱发电位与电刺激术定位脑功能区

目的探讨脑功能区手术中利用脑皮质体感诱发电位(SEP)及直接皮质电刺激定位脑功能区的方法及意义。方法对10例脑功能区病变病人在唤醒麻醉下进行手术，利用皮质SEP及皮质直接电刺激定位感觉区、运动区及语占区，住保护脑功能区的前提下，手术切除病变。结果7例病人利用SEP及皮质电刺激确定出运动感觉区，其中4例利用SEP位相倒置确定出中央沟，3例病变位于左侧额颞叶的病人通过皮质直接电刺激确定出语言区?术后功能均较术前明显好转。结论术中SEP及直接皮质电刺激可准确、实时确定脑功能区，最大程度地保护功能，切除病变。     

大脑语言运动区手术中的神经电生理监测(附52例分析)

目的研究大脑语言运动区病变手术中神经电生理监测的方法。方法对52例病变位于语言运动区的病人采用术中唤醒全麻，联合监测皮质体感诱发电位、直接皮质电刺激、肌电图及脑电图，同时行显微手术切除病变。结果全切除42例，次全切除10例。术中记录到典型的皮质体感诱发电位38例，其中波形倒置23例，最大波幅者20例。皮质电刺激与体感诱发电位所判定的中央前回位置完全相符者33例．皮质体感诱发电位不典型者电刺激阳性5例。肌电图变化与肌肉运动相符者20例，肌电图出现反应波而未见肌肉运动者10例。脑电图示癫痫波20例，广泛性慢波40例。术后症状改善或消失47例。结论语言运动区病变采用术中唤醒全麻，联合监测皮质体感诱发电位、直接皮质电刺激、肌电图与脑电图等神经电生理指标，有助于在最大限度保留脑功能的前提下全切除病变．保证手术安全．明显减少术后功能障碍的发生。     

术中体感诱发电位监测联合直接皮层电刺激技术在脑功能区手术中的应用

目的:探讨皮层体感诱发电位(SEP)波形位相倒置、术中直接电刺激(DCES)联合监测定位脑功能区的方法及意义.方法:在对37例运动感觉功能区占位患者术中采用SEP波形翻转、DCES定位感觉区和运动区的前提下,手术切除病变.结果:34例病人成功引出SEP,其中25例记录到明确的SEP的位相倒置,藉此定位中央沟,其中23例患者成功引出运动诱发电位(MEP),定位出感觉、运动皮层.有3例既未引出SEP也未引出MEP.术后患者脑功能大部分好转,未出现永久性功能障碍.结论:颅内占位患者术中联合采用SEP波形位相倒置与DCES监测技术定位,能在最大限度切除肿瘤的同时有效保护运动功能.     

中央沟区病变继发癫痫的显微手术治疗

目的 探讨中央沟区病变继发癫痫的显微手术治疗.方法 总结35例首发症状为癫痫的中央沟区病变,应用长程脑电图、偶极子、皮层电极定位致病灶;MRI结合术中皮质体感诱发电位、皮质刺激术定位脑功能区,显微镜下脑沟人路,保护脑功能区,病变切除后功能区残余癫痫波应用脑皮层热灼.结果 术后随访1-3年,疗效达到Engel I级31例、Ⅱ级4例、没有Ⅲ、Ⅳ级患者.术后3个月肢体功能障碍较术前改善23例,不变7例,加重5例,无手术死亡.结论 准确定位致痫灶和功能区,脑沟入路皮质下切除病变,配合功能区残余癫痫波皮层热灼,能保护肢体功能、控制癫痫的发作.     

超高场磁共振功能成像辅助切除躯体感觉区胶质瘤(附5例报告)

目的应用超高场磁共振功能成像技术进行手术前后研究脑躯体感觉功能区肿瘤与功能区的定位,辅助切除躯体感觉功能区胶质瘤。方法5例邻近或累及躯体感觉功能区的胶质瘤患者,术前行双手持物对接刺激策略,在3.0T磁共振采用血氧水平依赖(BOLD)原理进行图像采集,经工作站(Leonardo syngo 2003A,Siemens)提供的BOLD功能图像分析软件包进行分析获得脑运动功能区的激活图像,参与神经外科手术方案的制定。所有患者均在唤醒麻醉下进行显微外科手术,在术前脑功能磁共振图像指导下利用皮质直接电刺激定位感觉区与运动区。在保护脑功能区功能不受损的前提下,最大程度地切除胶质瘤。术前、术后均行KPS评分,判断患者的状态。结果(1)5例躯体感觉功能区胶质瘤,通过此项技术获得了较好的BOLD功能磁共振成像感觉功能区激活图像,定位躯体感觉功能区。(2)患者在唤醒麻醉下,在术前脑功能磁共振图像指导下利用直接皮质电刺激快捷、准确进行中央后回定位,两者具有良好的一致性。结论应用3.0T MRI可以于术前更好地利用BOLD技术显示躯体感觉功能区与脑胶质瘤的解剖关系,以指导唤醒麻醉下直接皮质电刺激定位躯体感觉功能区的手术,实现最大程度保护患者重要的功能并最大程度地切除肿瘤。     

电生理监测在中央回及其相邻区域胶质瘤手术中的临床应用

目的探讨应用皮质体感诱发电位、皮质运动诱发电位和皮质脑电图定位功能区,提高毗邻脑功能区胶质瘤切除手术的有效性和安全性。方法通过影像学检查筛选18例中央回及其毗邻部位的胶质瘤患者,经功能磁共振成像和脑磁图初步定位功能区;术中以皮质体感诱发电位和运动诱发电位进一步确定脑功能区、脑电图明确致癎灶位置,避开功能区切除肿瘤和（或）致癎灶;术后于瘤腔内植入放射性同位素¹²⁵Ⅰ和缓释型化疗药物5-氟尿嘧啶。结果 18例患者中1例肿瘤全切除、13例次全切除、4例部分切除。手术后第6、12和24个月疗效评价,无进展生存期平均为11个月;客观有效率分别为13/1 8、9/18和6/18;疾病控制率15/18、13,18和10/18。手术前和术后第6、12、24个月时的Karnofskv生活质量评分分别为（84.13±12.88）、（78.20±15.13）、（62.35±13.21）和（46.57±16.93）,各观察时间点之间比较差异有统计学意义（P<0.01）。术后并发症发生率为6,18例（肌力下降2例、感觉减退3例、肌力与感觉同时减退1例）。结论采用术中神经电生理学监测方法定位功能区及致癎灶,可在保留功能的情况下指导切除中央回及其毗邻部位胶质瘤。术后瘤腔内行间质放化疗对延长患者生存期、减少肿瘤复发有一定临床意义。     

电生理监测在中央回及其相邻区域胶质瘤手术中的临床应用

目的探讨应用皮质体感诱发电位、皮质运动诱发电位和皮质脑电图定位功能区,提高毗邻脑功能区胶质瘤切除手术的有效性和安全性。方法通过影像学检查筛选18例中央回及其毗邻部位的胶质瘤患者,经功能磁共振成像和脑磁图初步定位功能区;术中以皮质体感诱发电位和运动诱发电位进一步确定脑功能区、脑电图明确致痼灶位置,避开功能区切除肿瘤和（或）致痼灶;术后于瘤腔内植入放射性同位素125I和缓释型化疗药物5．氟尿嘧啶。结果18例患者中1例肿瘤全切除、13例次全切除、4例部分切除。手术后第6、12和24个月疗效评价,无进展生存期平均为11个月;客观有效率分别为13／18、9／18和6／18;疾病控制率15／18、13／18和10／18。手术前和术后第6、12、24个月时的Karnofsky生活质量评分分别为（84．13±12．88）、（78．20±15．13）、（62．35±13．21）和（46．57±16．93）,各观察时间点之间比较差异有统计学意义（P〈0．01）。术后并发症发生率为6／18例（肌力下降2例、感觉减退3例、肌力与感觉同时减退1例）。结论采用术中神经电生理学监测方法定位功能区及致痼灶,可在保留功能的情况下指导切除中央回及其毗邻部位胶质瘤。术后瘤腔内行间质放化疗对延长患者生存期、减少肿瘤复发有一定临床意义。     

脊髓运动诱发电位监测在手术中的应用

目的 评价脊髓运动诱发电位监测在脊柱脊髓手术中的作用.方法 通过连续短脉冲头皮电刺激,应用硬膜外电极于脊髓记录18例脊柱脊髓疾病患者手术过程中的运动诱发电位.根据日本整形外科协会(JOA)评分标准对患者手术前后神经功能进行评价.结果 以手术中首次记录到的脊髓运动诱发电位D1波波幅和潜伏期作为参照值,8例脊柱侧弯患者施行脊柱矫形手术过程中记录到的脊髓运动诱发电位D1波波幅和潜伏期均无异常变化;10例行椎管内及脊髓手术患者,手术中脊髓运动诱发电位D1波波形改变、波幅降低,改变手术方向或经短暂休息后恢复正常.根据JOA评分,手术后所有患者感觉和运动功能均较手术前明显改善,差异有统计学意义(Z=-2.646,P=0.008;Z=-2.828,P=0.005).结论 手术中脊髓运动诱发电位监测可及时、客观地反映神经功能,有效避免手术中神经损伤及手术后神经功能障碍.在监测过程中,头皮电刺激记录到的脊髓运动诱发电位D1波波形清晰、稳定,且不受外界因素的影响.     

T2灰阶反转图像在神经外科手术中的应用

目的 总结评价T2灰阶反转图像在神经外科手术中的作用.方法 将常规磁共振T2图像融合在神经导航中,并进行灰阶反转处理.对36例神经外科手术患者,采朋T2厌阶反转图像进行脑沟、脑回等结构定位,并在13例功能区肿瘤手术中.对体感诱发电位、皮质直接电刺激对中央沟、中央前回手区的定位结果与T2灰阶反转图像定位结果进行比较.结果 T2灰阶反转图像在显示脑沟、脑回、脑表面浅静脉等结构,以及脑水肿范围上比其他序列网像清晰.应用T2灰阶反转网像导航定位中央沟及中央前回手运动区在此组病例中与体感诱发电位、皮质直接电刺激结果完全符合.结论 T2灰阶反转图像对脑沟、脑回等脑结构的显示、定位可靠,可以替代神经电生理对中央沟的空间定位,并为图像引导的神经外科手术提供了更丰富的网像信息.     

应用术中直接电刺激最大安全切除功能区胶质瘤

目的 探讨直接电刺激在功能区胶质瘤手术中应用的意义.方法 回顾性分析157例大脑功能区胶质瘤术中直接电刺激的临床资料.结果 皮质电刺激4例阴性刺激,139例刺激出运动区皮质,21例感觉区,91例出现语言相关区皮质.数数中断的阳性区主要位于左中央前回下方、左额下回盖部、左额下回三角部、左额中回后部和额上回后部.术后MRI示胶质瘤全切92例(58.6％),次全切55例,部分切除10例.术后53例出现短暂肢体运动障碍;39例出现短暂语言功能障碍,4例(2.5％)出现永久性神经功能障碍.结论 术中直接电刺激是一种可靠元创的脑功能区定位方法,在胶质瘤手术中应用此技术可达到最大安全切除肿瘤,同时为国人功能区脑皮质定位提供帮助.     

Location of primary somatosensory area in cerebral arteriovenous malformation involving sensorimotor area]

The purpose of this study was to investigate the cortical reorganization associated with congenital brain lesion such as intracerebral arteriovenous malformation (AVM). Dipole source localization of somatosensory evoked potential (SEP) was performed in five patients with AVM encompassing sensorimotor cortex. Dipole tracing method combined with the scalp-skull-brain head model (Homma et al., 1994) was used to locate dipole source of an early cortical component of SEP elicited by median nerve electrical stimulation. The location of dipole source of SEP, which could be considered as the hand area of primary somatosensory area, was shown in the realistic section of the head and could be easily superimposed on the magnetic resonance imaging. SEP was recorded three times in each patients and the results were reproducible. In 2 patients whose postcentral gyrus was not involved in AVM, the dipole source of SEP was localized in the intact postcentral gyrus. The locations of dipole sources of SEP in the both hemisphere were symmetrical. In 3 patients whose postcentral gyrus was encompassed by AVM, the dipole source of SEP was localized in the surrounding intact gyrus which was distant from the usual region of postcentral gyrus. Somatotopy was different from the normal pattern. The hand area was located more medially than usual observed in normal postcentral gyrus. Despite the paucity of the number of patients and data obtained by dipole source localization, our findings support the existence of reorganization in the cerebral cortex with congenital lesion such as AVM. These findings of aberrant mapping of cortical function may be explained by the plasticity of brain function. The developing brain can inherit function that would normally have been performed by the region of brain involved in the lesion. We demonstrated that dipole tracing of SEP was a noninvasive method used to localize areas of eloquent cortex in patients harboring AVM. This method is of value in treatment planning.     

Localisation of the sensorimotor cortex during surgery for brain tumours: feasibility and waveform patterns of somatosensory evoked potentials

OBJECTIVE: Intraoperative localisation of the sensorimotor cortex using the phase reversal of somatosensory evoked potentials (SEPs) is an essential tool for surgery in and around the perirolandic gyri, but unsuccessful and perplexing results have been reported. This study examines the effect of tumour masses on the waveform characteristics and feasibility of SEP compared with functional neuronavigation and electrical motor cortex mapping. METHODS: In 230 patients with tumours of the sensorimotor region the SEP phase reversal of N20-P20 was recorded from the exposed cortex using a subdural grid or strip electrode. In one subgroup of 80 patients functional neuronavigation was performed with motor and sensory magnetic source imaging and in one subgroup of 40 patients the motor cortex hand area was localised by electrical stimulation mapping. RESULTS: The intraoperative SEP method was successful in 92% of all patients, it could be shown that the success rate rather depended on the location of the lesion than on preoperative neurological deficits. In 13% of the patients with postcentral tumours no N20-P20 phase reversal was recorded but characteristic polyphasic and high amplitude waves at 25 ms and later made the identification of the postcentral gyrus possible nevertheless. Electrical mapping of the motor cortex took up to 30 minutes until a clear result was obtained. It was successful in 37 patients, but failed in three patients with precentral and central lesions. Functional neuronavigation indicating the tumour margins and the motor and sensory evoked fields was possible in all patients. CONCLUSION: The SEP phase reversal of N20-P20 is a simple and reliable technique, but the success rate is much lower in large central and postcentral tumours. With the use of polyphasic late waveforms the sensorimotor cortex may be localised. By contrast with motor electrical mapping it is less time consuming. Functional neuronavigation is a desirable tool for both preoperative surgical planning and intraoperative use during surgery on perirolandic tumours, but compensation for brain shift, accuracy, and cost effectiveness are still a matter for discussion.     

Abnormal gating of somatosensory inputs in essential tremor.

OBJECTIVE: To study whether sensorimotor cortical areas are involved in Essential Tremor (ET) generation.BACKGROUND: It has been suggested that sensorimotor cortical areas can play a role in ET generation. Therefore, we studied median nerve somatosensory evoked potentials (SEPs) in 10 patients with definite ET.METHODS: To distinguish SEP changes due to hand movements from those specifically related to central mechanisms of tremor, SEPs were recorded at rest, during postural tremor and during active and passive movement of the hand. Moreover, we recorded SEPs from 5 volunteers who mimicked hand tremor. The traces were further submitted to dipolar source analysis.RESULTS: Mimicked tremor in controls as well as active and passive hand movements in ET patients caused a marked attenuation of all scalp SEP components. These SEP changes can be explained by the interference between movement and somatosensory input ('gating' phenomenon). By contrast, SEPs during postural tremor in ET patients showed a reduction of N20, P22, N24 and P24 cortical SEP components, whereas the fronto-central N30 wave remained unaffected.CONCLUSIONS: Our findings suggest that in ET patients the physiological interference between movement and somatosensory input to the cortex is not effective on the N30 response. This finding thus indicates that a dysfunction of the cortical generator of the N30 response may play a role in the pathogenesis of ET.     

Topography and intracranial sources of somatosensory evoked potentials in the monkey. II. Cortical components

Averaged somatosensory evoked potentials (SEPs) and associated multiple unit activity (MUA) were recorded from a series of epidural and intracortical locations following stimulation of the contralateral median nerve in the monkey. Cortical components were differentiated from the earlier subcortical activity and the intracerebral distribution and sources of each cortical potential were determined. Under barbiturate anesthesia the SEP wave form is simplified and can be wholly attributed to two sources. The earliest cortical activity consists of a biphasic P10-N20 wave which is generated in the posterior bank of the central sulcus. A second wave form, P12-N25, originates in the crown of the postcentral gyrus. No other cortical areas are active. In the alert state the morphology of the surface SEP is complex and reflects the interaction of volume conducted activity from several adjacent cortical sources. The wave form overlying the hand area of the postcentral gyrus consists of P12, P20, P40, N45 and P110. Precentral recordings exhibit P10, P13, N13, N20, P24, N45 and P110. Six anatomical sources have been identified. P10 and N20 originate in the posterior bank of the central sulcus including areas 3a and 3b and are volume conducted in an anteroposterior direction. P12 originates in area 1 as well as the anterior portion of area 2. P20 is generated in the medial portion of the postcentral gyrus including area 5. The source of P40 lies within the lateral portion of the parietal lobe including area 7b. Two components were generated in precentral cortex: P13/N13 originates principally in area 4 within the anterior bank of the central sulcus and P24 reflects activity in the anteromedial portion of the precentral gyrus including area 6. The long latency SEP components, N45 and P110, are generated widely within the somesthetic areas of postcentral cortex. The early cortical SEP components recorded in the monkey closely resemble in configuration and topography those recorded from man although the latter are longer in latency, reflecting interspecies differences in the length of conduction pathways as well as in cortical processing time.     

Thin-film epidural microelectrode arrays for somatosensory and motor cortex mapping in rat

Assessments of somatosensory and motor cortical somatotopy in vivo can provide important information on sensorimotor physiology. Here, novel polyimide-based thin-film microelectrode arrays (72 contacts) implanted epidurally, were used for recording of somatosensory evoked potentials (SEPs) and somatosensory cortex somatotopic maps of the rat. The objective was to evaluate this method with respect to precision and reliability. SEPs and somatosensory maps were measured twice within one session and again after 8 days of rest. Additionally, motor cortex maps were acquired once to assess the spatial relationship between somatosensory and motor representations of fore- and hindlimb within one individual. Somatosensory maps were well reproduced within and between sessions. SEP amplitudes and latencies were highly reliable within one recording session (combined intraclass correlation 90.5%), but less so between sessions (21.0%). Somatosensory map geometry was stable within and between sessions. For the forelimb the somatosensory representation had a 30% overlap with the corresponding motor area. No significant overlap was found for the hindlimb. No evidence for cortical injury was found on histology (Nissl). Thin-film epidural electrode array technology enables a detailed assessment of sensorimotor cortex physiology in vivo and can be used in longitudinal designs enabling studies of learning and plasticity processes.     

脑功能区胶质瘤的手术策略

目的探讨唤醒麻醉状态下切除脑功能区胶质瘤的手术方法及意义。方法13例脑功能区胶质瘤经神经导航病灶定位术中唤醒麻醉,皮层诱发电位及皮层电刺激定位脑功能区,在清醒状态下切除脑功能区病变。结果全部病例均在术中获得安全可靠的麻醉唤醒,清醒状态下脑功能区的定位和最大限度地肿瘤切除,其中6例获得皮层体感诱发电位检测确定中央沟;9例经皮质刺激术明确运动区;4例通过皮质刺激术基本确定语言运动中枢。肿瘤全切11例,次全切除2例。术后出现暂时性神经功能障碍或功能障碍加重有11例,神经功能完全恢复正常10例。1例术中出现癫痫发作,1例在唤醒过程中出现一过性脑肿胀;全部患者术后无痛苦回忆。结论对脑功能区胶质瘤运用唤醒麻醉,神经导航病灶定位,皮层电刺激和皮层诱发电位定位脑功能区技术能较为可靠地明确脑功能区与肿瘤切除范围的关系,在清醒状态下切除肿瘤实时监测脑功能状态,能够最大限度地切除脑功能区病变和最大程度地保护脑功能。     

Functional changes of the cortical motor system in hereditary spastic paraparesis

Background – Hereditary spastic paraparesis (HSP) is a heterogeneous group of disorders characterized by progressive bilateral lower limb spasticity. Functional imaging studies in patients with corticospinal tract involvement have shown reorganization of motor circuitry. Our study investigates functional changes in sensorimotor brain areas in patients with HSP. Methods – Twelve subjects with HSP and 12 healthy subjects were studied. Functional magnetic resonance imaging (fMRI) was used to measure brain activation during right‐hand finger tapping. Image analysis was performed using general linear model and regions of interest (ROI)‐based approach. Weighted laterality indices (wLI) and anterior/posterior indicies (wAI and wPI) were calculated for predefined ROIs. Results and discussion – Comparing patients and controls at the same finger‐tapping rate (1.8 Hz), there was increased fMRI activation in patients’ bilateral posterior parietal cortex and left primary sensorimotor cortex. No differences were found when comparing patients and controls at 80% of their individual maximum tapping rates. wLI of the primary sensorimotor cortex was significantly lower in patients. Subjects with HSP also showed a relative increase in the activation of the posterior parietal and premotor areas compared with that of the primary sensorimotor cortex. Our findings demonstrate an altered pattern of cortical activation in subjects with HSP during motor task. The increased activation probably reflects reorganization of the cortical motor system.     

Mapping of early and late human somatosensory evoked brain potentials to phasic galvanic painful stimulation

In the present study, we modeled the spatiotemporal evolution of human somatosensory evoked cortical potentials (SEPs) to brief median-nerve galvanic painful stimulation. SEPs were recorded (-50 to +250 ms) from 12 healthy subjects following nonpainful (reference), slight painful, and moderate painful stimulations (subjective scale). Laplacian transformation of scalp SEPs reduced head volume conduction effects and annulled electric reference influence. Typical SEP components to the galvanic nonpainful stimulation were contralateral frontal P20-N30-N60-N120-P170, central P22-P40, and parietal N20-P30-P60-P120 (N = negativity, P = positivity, number = latency in ms). These components were observed also with the painful stimulations, the N60, N120, P170 having a longer latency with the painful than nonpainful stimulations. Additional SEP components elicited by the painful stimulations were parietomedian P80 as well as central N125, P170 (cP170), and P200. These additional SEP components included the typical vertex negative-positive complex following transient painful stimulations. Latency of the SEP components exclusively elicited by painful stimulation is highly compatible with the involvement of A delta myelinated fibers/spinothalamic pathway. The topography of these components is in line with the response of both nociceptive medial and lateral systems including bilateral primary sensorimotor and anterior cingulate cortical areas. The role of attentive, affective, and motor aspects in the modulation of the reported SEP components merits investigation in future experiments.     

Somatosensory evoked potentials following stimulation of the tibial, peroneal and sural nerves using four different montages

Cortical and lumbar somatosensory evoked potentials (SEPs) were recorded following unilateral stimulation of the tibial, peroneal and sural nerves in 20 normal adults. The active cortical electrode (Cz) was referred to either a cephalic (mid-forehead, contralateral central scalp, linked ears) or a non-cephalic (contralateral shoulder) site. The configuration of the short-latency cortical SEP waveforms was nearly identical irrespective of the nerve stimulated or the location of the reference. Central conduction times (CCTs) were also calculated by subtracting the peak latency of the lumbar SEP from that of the primary cortical response following stimulation of the tibial and peroneal nerves. A stronger relationship was consistently observed between the absolute cortical latency and height than between CCT and height. The potential clinical applications of the results are discussed.     

Use of cortical somatosensory evoked potentials in surgical treatment of AVMs in and around the central sulcus

Electric potentials named N1, P2 are recorded from electrodes on the primary sensory cortex when the contralateral median nerve is electrically stimulated transcutaneously at the wrist. N1 is negative wave about 20 msec in peak latency, derived from cortex area 3b, and P2 is positive wave about 24 msec in peak latency, elicited from area 1 and 2. These components will show phase reversals between two responses recorded from precentral and postcentral electrodes pairs. In this report, we attempted to recognize central fissure in 4 cases of arteriovenous malformation in sensorimotor cortex with the benefit of the intraoperative cortical SEPs. We obtained successful recording of phase reversal and identified central fissure in all cases, to whom several anesthetic agents which were said to affect SEP in latency and amplitude were administered continuously during operation. Electrophysiologically recognized central fissures did not coincide with central sulcus arteries those identified by angiographic measurements of two patients. Avoiding injury to the motor cortex, 3 AVMs were completely resected without causing additional neurological deficits. One case whose nidus was hidden into the motor cortex was given up for its resection. In this case the clipping of feeding vessels was chosen for the treatment. Direct monitoring of SEP gives us many additional informations to radiological landmarks concerning the place of sensorimotor cortex and the selection of the surgical approach to the paracentral lesion.