Objective To investigate the relationship between graded spinal cord ischemia/reperfusion injury and somatosensory evoked potentials(SEP),neurologic function score（NFS）and the histopathological changes of spinal cord. Methods Forty rabbits were randomized and equally divided into 4 groups: shamoperation group, ischemia for 30min, 45min and 60min groups. The spinal cord ischemiareperfusion injury model was created by occlusion of the abdominal aorta in rabbits. SEP was monitored before ischemia,5,10minutes after ischemia, 15, 30 minutes, 1,2, 24 and 48 hours after reperfusion. NFS was evaluated at 6,12,24 and 48 hours after reperfusion.The pathological changes of spinal cord were observed after reperfusion 48 hours. Results The pathological characters with mild,moderate and severe spinal cord ischemia/reperfusion injury could be simulated by declamping after 30， 45 and 60 minutes infrarenal aorta crossclamping. SEP amplitude returned to normal after reperfusion 15 minutes（Pgt;0.05）and SEP latency returned to normal after reperfusion 30 minutes（Pgt;0.05）during mild spinal cord ischemia/reperfusion injury.SEP amplitude returned to normal after reperfusion 30 minutes（Pgt;0.05）and SEP latency returned to normal after reperfusion 60 minutes（Pgt;0.05）during moderate spinal cord ischemia/reperfusion injury. SEP latency increased and SEP amplitude decreased during severe spinal cord ischemia/reperfusion injury,compared with other groups, there were significant differences in SEP latency and SEP amplitude by clamping the infrarenal aorta for 60min（Plt;0.01）. With graded spinal cord ischemia/reperfusion injury, compared with shamoperation group, spinal cord ischemiareperfusion groups had significant differences in NFS（Plt;0.01）. Conclusion SEP is much quicker in the recovery of amplitude than latency during spinal cord ischemia/reperfusion. SEP is a sensitive and accurate index for spinal cord function during ischemia/reperfusion injury. SEP monitoring spinal cord ischemia/reperfusion injury during operation provides experimental basis for clinical application.
OBJECTIVE: To investigate the characteristics and the pathologic classification of electrical-injury nerve using somatosensory evoked potential(SEP) technique. METHODS: SEP were detected and evaluated in 12 cases with electrical-injury nerve during operation, electrical stimulation was commenced from distal side of nerve where the structure of nerve looks normal under operating microscope, up to proximal side until evoking out a stable SEP predeterminate virtual value. Pathological examination and the following functional evaluation were compared with the values of SEP. RESULTS: At the site of nerve looking normal under operating microscope, perineurium appears normal or slightly thicken. But there are obvious fibrosis and fibrotic proliferation between fascicular and intrafascicular. Vessel plexus is not seen. At SEP stabilizely evoked site, nervous construction is normal, there are visible interfascicular vessel plexus and connective tissue appears loose. Comparing SEP values with pathological section, amplitude and latency of SEP is positively correlative with the quality of nerve. Eight cases repaired with SEP technique to select the anastomosis site for nerve transplantation were followed up, two-point discrimination reached grade III (America hand surgery association criterion) within 62.5% cases. CONCLUSION: SEP technique is valuable method for functional evaluation of electrical- injury nerve which has a complicated pathology. The pathology of electrical-injury nerve can be classified into 4 types, type A: fibrosis of nerve; type B: nerve looking normal under operation microscope, perineurium appears thicken, and there are obvious fibrosis and fibrotic proliferation between fascicular and intrafascicular, vessel plexus is rarely to see; type C: nerve looks normal, lymphocyte infiltration exists and it is obvious that there are many physalis-like, retrogressive construction in the section; type D: nervous construction is normal, there are visible interfascicular vessel plexus, and connective tissue appears loose, SEP always can be stably evoked.
ObjectiveTo investigate the influence and management of blood pressure on intraoperative cortex somatosensory evoked potential (CSEP) in the surgery of severe scoliosis. MethodsFrom June 2009 to March 2012, CSEP monitoring during surgery of severe scoliosis were performed on 43 patients, in whom 4 had abnormal CSEP while blood pressure decline. There were 2 males and 21 females. The average age was 16.1 years. The average preoperative Cobb angle was 96.1° (88.7-107.5°). Latency and amplitude of cortical potentials were observed with the value of the latency extension more than 10% and peak amplitude reduction more than 50% defined as abnormality. The arterial blood pressure (ABP) was used to evaluate the intraoperative blood pressure. ResultThe incidence rate of bilateral CSEP wave abnormalities after blood pressure decline was 9.3% in the surgery of severe scoliosis. One case of CSEP abnormality occurred during the installing of pedicle screws; two cases during the Smith-Petersen osteotomy, and one case during the bone graft after correction. With the ABP dropping to about 92/57 mm Hg (1 mm Hg=0.133 kPa), the amplitude decreased 80% in 24-33 minutes. After the ABP increased to 113/75 mm Hg by treatment, the index was backed up normally in 5-10 minutes. There was no neurological complication after surgery. ConclusionA high incidence rate and significantly decreased amplitude of CSEP abnormality after blood pressure decline in the surgery of severe scoliosis are found. Intraoperative stable blood pressure should be maintained for patients with severe scoliosis. When the amplitude of CSEP decreases followed with blood pressure decline, blood pressure should be actively corrected by treatment, so that the CSEP may get back to normal as soon as possible.
ObjectiveTo explore changes on Electroencephalograph (EEG) and Evoked Potential (EP) changes in autoimmune encephalitis.MethodsEight cases with autoimmune encephalitis from Sichuan people's hospital during July 18th 2014 to July 18th 2016 were recruited. The inclusion criteria included:① The blood and cerebral spinal fluid (CSF) of patients were sent to Neurology Lab of Peking Union Medical College Hospital for autoimmunerelated antibody analysis and confirmed as autoimmune encephalitis.2 Patient had done at least 2 or more times of routine EEG or video EEG (VEEG). 1 or more times of auditory brainstem response (ABR), Visual evoked potential (VEP) and Somatosensory evoked potential (SEP) for both upper and lower limbs. 3 Patients had classical clinical manifestation of autoimmune encephalitis as abnormal psychomotor behaviors, seizures, memory loss, fever, headache, and even disturbance of consciousness or decreased ventilate function.ResulstOf 8 patients in this study, 5 were anti NMDA-R encephalitis, 2 were anti GABABR encephalitis, and 1 was positive for both antibodies. The EEG profile of 5 anti NMDA-R encephalitis:2 of them had β wave in early stage (about 10th day) and δ wave with fast wave even appeared as δ brush in middle stage (about 20th day). They all had severe symptoms and long hospitalization but negative MRI. Another 2 of them could be seen sparsely distributed sharp wave and sharp-slow wave in their EEG. Their EEG gradually turned to normal when their symptoms gradually disappeared. The last one had normal EEG during the whole disease course. The EEG profile of anti GABAB-R encephalitis as following. 1 was dominant by slow wave and EEG went normal after effective treatment and the other showed generalized α wave especially α wave in frontal region. The latter patient withdraw treatment. For the only 1 both antibodies positive patient, EEG showed slow wave and it turned to normal when symptoms disappeared. EP showed some abnormalities with wave amplitude and latency changes in some patients.EP (SEP、VEP) turned to normal when symptoms disappeared.ConclusionThe EEG present differently in different types of autoimmune encephalitis and change with stages of disease. EEG may be used as an indicator for prognosis as well. When EEG shows fast wave with the history of patient points to encephalitis, blood and CSF antibodies for NMDA-R should be checked routinely. Generalized α wave on EEG should also be an indicator for checking GABAB-R. More researches should be done for EP changes in autoimmune encephalitis for our study was based on a small patient number.