EEG power spectral density under Propofol and its association with burst suppression,a marker of cerebral fragility

ObjectiveUnder General Anesthesia (GA), age and Burst Suppression (BS) are associated with cognitive postoperative complications, yet how these parameters are related to per-operative EEG and hypnotic doses is unclear. In this prospective study, we address this question comparing age and BS occurrences with a new score (BP_TIVA) based on Propofol doses, EEG and alpha-band power spectral densities, evaluated for SEF₉₅ = 8–13 Hz.Methods59 patients (55 [34–67] yr, 67% female) undergoing neuroradiology or orthopedic surgery were included. Total IntraVenous Anesthesia was used for Propofol and analgesics infusion. Cerebral activity was monitored from a frontal electrodes montage EEG.ResultsBP_TIVA was inversely correlated with age (Pearson r = −0.78, p < 0.001), and was significantly lower (p < 0.001) when BS occurred during the GA first minutes (induction). Additionally, the age-free BP_TIVA score was better associated with BS at induction than age (AUC = 0.94 versus 0.82, p < 0.05).ConclusionWe designed BP_TIVA score based on hypnotics and EEG. It was correlated with age yet was better associated to BS occurring during GA induction, the latter being a cerebral fragility sign.SignificanceThis advocate for an approach based on evaluating the cerebral physiological age (« brain age ») to predict postoperative cognitive evolution.     

Nonoperatively treated burst fractures of the thoracic and lumbar spine in adults: a 23- to 41-year follow-up

BACKGROUND CONTEXT: Several studies report a favorable short-term outcome after nonoperatively treated two-column thoracic or lumbar burst fractures in patients without neurological deficits. Few reports have described the long-term clinical and radiological outcome after these fractures, and none have, to our knowledge, specifically evaluated the long-term outcome of the discs adjacent to the fractured vertebra, often damaged at injury and possibly at an increased risk of height reduction and degeneration with subsequent chronic back pain. PURPOSE: To evaluate the long-term clinical and radiological outcome after nonoperatively treated thoracic or lumbar burst fractures in adults, with special attention to posttraumatic radiological disc height reduction. STUDY DESIGN: Case series. PATIENT SAMPLE: Sixteen men with a mean age of 31 years (range, 19-44) and 11 women with a mean age of 40 years (range, 23-61) had sustained a thoracic or lumbar burst fracture during the years 1965 to 1973. Four had sustained a burst fracture Denis type A, 18 a Denis type B, 1 a Denis type C, and 4 a Denis type E. Seven of these patients had neurological deficits at injury, all retrospectively classified as Frankel D. OUTCOME MEASURES: The clinical outcome was evaluated subjectively with Oswestry score and questions regarding work capacity and objectively with the Frankel scale. The radiological outcome was evaluated with measurements of local kyphosis over the fractured segment, ratios of anterior and posterior vertebral body heights, adjacent disc heights, pedicle widths, sagittal width of the spinal canal, and lateral and anteroposterior displacement. METHODS: From the radiographical archives of an emergency hospital, all patients with a nonoperatively treated thoracic or lumbar burst fracture during the years 1965 to 1973 were registered. The fracture type, localization, primary treatment, and outcome were evaluated from the old radiographs, referrals, and reports. Twenty-seven individuals were clinically and radiologically evaluated a mean of 27 years (range, 23-41) after the injury. RESULTS: At follow-up, 21 former patients reported no or minimal back pain or disability (Oswestry Score mean 4; range, 0-16), whereas 6 former patients (of whom 3 were classified as Frankel D at baseline) reported moderate or severe disability (Oswestry Score mean 39; range, 26-54). Six former patients were classified as Frankel D, and the rest as Frankel E. Local kyphosis had increased by a mean of 3 degrees (p<.05), whereas the discs adjacent to the fractured vertebrae remained unchanged in height during the follow-up. CONCLUSIONS: Nonoperatively treated burst fractures of the thoracic or lumbar spine in adults with or without minor neurological deficits have a predominantly favorable long-term outcome, and there seems to be no increased risk for subsequent disc height reduction in the adjacent discs.     

椎弓根固定结合椎体成形术治疗胸腰椎爆裂骨折

目的探讨椎弓根固定结合经椎弓根椎体内植骨行椎体成形术治疗胸腰椎爆裂骨折的疗效。方法采用椎管环形减压、短节段椎弓根螺钉系统固定结合经椎弓根椎体内植骨治疗胸腰椎爆裂骨折116例,其中93例获得随访。术前及术后随访行X线和CT检查,测量伤椎椎体中央高度值,比较植骨后椎体高度的恢复程度,同时观察植骨融合情况。采用配对t检验方法进行统计学分析。结果93例患者术后平均随访24.2个月,90%以上患者伤椎椎体高度恢复并维持良好,无塌陷。伤椎椎体中央高度值犤T12(3.14±0.41)cm,L1(3.33±0.34)cm犦与正常值犤(T12(3.26±0.38)cm,L1(3.47±0.61)cm)犦比较,差异无显著性意义(P>0.05)。未出现植骨操作引起的神经血管并发症。CT显示椎体内植骨块边缘模糊,融合良好,植骨块无吸收现象。结论后路椎管环形减压及内固定时,经伤椎椎弓根进行椎体内植骨行椎体成形术可恢复伤椎椎体高度,重建前、中柱的稳定性,预防术后椎体塌陷的发生。     

Vertebroplasty and Kyphoplasty in Spinal Trauma

Abstract Kyphoplasty and vertebroplasty have become recognized procedures for the treatment of vertebral fractures, especially in patients with osteoporosis. In most cases of osteoporotic spinal vertebral fracture in elderly patients, polymethylmethacrylate (PMMA) cement is used to fill the defect and stabilize the vertebral body. The techniques of vertebroplasty and kyphoplasty differ in the possibility of realignment and reconstruction of the vertebral body and spinal column. Long-term results in terms of integration of the cement and bioreactivity of the vertebral body are still lacking; so, these procedures are still no options in the treatment of younger patients. Vertebroplasty and kyphoplasty show different success in the management of fresh traumatic spine fractures. The acute traumatic vertebral fracture has to be classified sensitively, to find the right indication for cement augmentation. Mild acute compression fractures can be treated by vertebroplasty or kyphoplasty, severe compression and burst fractures by combination of internal fixation and kyphoplasty. The indications for use of biological or osteoinductive cement in spinal fracture management must still be regarded as restricted owing to the lack of basic biomechanical research data. Such cement should not be used except in clinical studies.     

胸腰椎爆裂骨折椎管内骨片侵入倾向与对策

根据98例中获得随访的39例的X线、CT和MRI(24例)影像学资料,分析胸腰椎爆裂骨折椎管内骨片侵入倾向及对策。将爆裂骨折侵入椎管分为四类八型,宜采用Harrington器械钢丝或椎弓根螺钉钢板轴向撑开系统,使骨折复位,椎管容积恢复,毋需行后路椎管减压。本组取得良好效果。仅对骨片游离型需要切开椎管直接摘除骨片。     

Pathomechanismen der Epilepsie

Zusammenfassung Die Epilepsieforschung ist kein neues wissenschaftliches Feld—klinische und experimentelle Untersuchungen werden seit Jahrzehnten betrieben. Trotz dieser fortw?hrenden Bemühungen sind die Pathomechanismen der Epilepsie letztlich nicht vollst?ndig gekl?rt—allerdings gelangen in den letzten Jahren auch beachtliche Fortschritte. Vor allem durch die Kombination genetischer, molekularer und funktioneller Analysen konnten wichtige Teilaspekte der Entstehungsprozesse der Epilepsie aufgekl?rt werden. Der vorliegende übersichtsartikel soll nach einer kurzen Er?rterung der grunds?tzlichen Faktoren der Erregbarkeit einzelner Zellen und des neuronalen Zellverbandes in fünf kurzen Kapiteln einen überblick über den aktuellen Forschungsstand liefern. Innerhalb der ersten drei Abschnitte werden Ver?nderungen spannungsabh?ngiger Str?me, der synaptischen Transmission und deren Modulation sowie der Expression von Gap junctions beleuchtet. Darüber hinaus widmet sich ein Abschnitt morphologischen Ver?nderungen. Der letzte Teil behandelt Aspekte spezifischer genetischer Syndrome. Dieser Beitrag ist bereits in verkürzter Form in der Zeitschrift „Klinische Neurophysiologie“, Bd. 37 (2006), S. 1–9, unter dem Titel „Pathophysiologie der Epilepsie“ erschienen.     

S-F内固定器治疗胸腰椎爆裂型骨折

目的　探讨使用S -F脊柱内固定器治疗胸腰椎爆裂型骨折的效果。方法　回顾分析从 2 0 0 0年 1月～ 2 0 0 2年 4月使用S-F脊柱内固定器治疗的胸腰椎爆裂型骨折 4 4例 ,比较手术前后的椎体前后缘高度 ,椎管狭窄程度 ,Cobb角及症状恢复情况。结果　经平均 2年左右的随访 ,术后椎体前缘平均高度达正常的 93 8%± 6 2 7% ,较术前增加了 4 2 5 3%。椎体后缘平均高度达到正常的 97 5 9%± 0 0 3% ,较术前增加了 1 6 5 2 %。脊柱后凸Cobb为 4 98°± 3 32°。较术前矫正了 1 4 6 8°。CT片显示椎体后突骨块占椎管前后径的比例为 9 5 9%± 7 2 1 % ,较术前减少 2 7 71 %。统计学分析差异有显著性 (P <0 0 5 )。有神经功能损伤者 ,术后平均改进一级以上。在术后二周与术后一年以上的X线片相比较其椎体前缘的高度平均仅丢失 1 0 % ,椎体后缘的高度平均丢失 0 8% ,Cobb角平均丢失 0 1°。结论　使用S -F脊柱内固定器治疗胸腰椎爆裂型骨折具有操作简单、复位完美、固定牢靠、疗效优良的优点。术中注意不宜过度撑开及双侧不对称 ,对椎板减压者宜作“H”型椎板后路植骨 ,横突间、关节突间植骨融合将提高疗效、减少并发症     

双凤尾钢板植骨内固定治疗胸腰椎爆裂骨折的生物力学测试

目的 对双凤尾钢板治疗胸腰椎爆裂骨折进行生物力学评价和临床应用观察。方法 取成年男性尸体脊柱标本(T12-L2),制成8具L1椎体爆裂骨折模型。按实际手术方法放置双凤尾钢板。对试件分别进行轴向和弯曲扭转加载测试。临床观察应用双凤尾钢板治疗胸腰椎爆裂骨折的效果。结果 压缩实验和弯曲扭转实验中,各点应变值与载荷均呈线性关系。当轴向载荷达到600N或扭矩达到600N·cm时,这种线性关系未改变。弯扭矩与模型两端之间相对扭转角的增加呈线性关系。弯扭矩达到600N·cm时,扭转角只有6.26°。临床观察表明双凤尾钢板固定可靠。结论 双凤尾钢板固定具有良好的稳定性,表现出高弹性,符合生物学固定的原则。值得临床推广应用。     

MEG Characterization of Spontaneous Alpha Rhythm in the Human Brain

The present piece of research studied the spontaneous alpha rhythm of the human brain by combining the use of a whole-cortex neuromagnetometer and Magnetic Resonance Imaging. Single trials of spontaneous brain activity were recorded from ten human subjects asked to rest, with their eyes either closed or open, in relaxed wakefulness. MEG measurements were conducted over a period of one and a half years. The replicability of the results was confirmed for eight subjects out of ten. For three subjects, the alpha rhythm did not show any reductions due to the opening of the eyes. Both field map pattern and location of the estimated source were persistently stationary during each of the bursts of oscillations of the alpha rhythm. Dipoles were concentrated in clusters, indicating the existence of several spatially distributed sources. The calcarine fissure, the parieto-occipital sulcus and the surrounding occipital and parieto-occipital areas were identified as cortical sites of the brain where the alpha rhythm may originate. For four subjects, the majority of the sources were located near or in the calcarine fissure, while for five subjects, they were located near or in the parieto-occipital sulcus and for the remaining subject they were equally divided between the two generation sites.     

Phasic stimulation of the locus coeruleus: Effects on activity in the lateral geniculate nucleus

Neurons in the locus coeruleus (LC) encode information related to behavioral state in a tonic pattern of firing and information related to the occurrence of a sensory stimulus in a phasic pattern of firing. The effects of phasic stimulation of the LC (6 pulses at 30 Hz), designed to approximate its physiological activation by sensory stimuli, were studied in the lateral geniculate nucleus (LGN) of anesthetized rats. Phasic stimulation of the LC significantly increased neuronal firing in the LGN with a mean latency 320 ms from onset of stimulation. Receiver operating characteristic analyses on a trial-by-trial basis showed that phasic LC stimulation can result in a highly discriminable signal in the LGN. This increased neuronal firing rate in the LGN was specific for the site of stimulation and was reduced by the norepinephrine synthesis inhibitor αmethyl-p-tyrosine and by intravenous WB-4101 (α₁-receptor antagonist). Neurons in the LGN have a singlespike firing mode when sensory information is faithfully relayed from retina to cortex and a burst-firing mode when the transfer of this information is degraded. Phasic LC stimulation reduced burst firing (2–5 ms interspike intervals, ISIs) at low frequencies ( ≤4 Hz) in the LGN, and for some neurons there was an absolute decrease in burst-like ISIs after LC stimulation, despite an increase in mean firing rate.