Median Nerve Somatosensory Evoked Potentials in Patients with Chiari Malformation

Abnormal SEP reflects dysfunction of the medial lemniscus and posterior cervical cord. These structures are likely to be affected in Chiari malformation. Therefore, SEP abnormalities may provide valuable information in patients with CM. However, the consistency of SEP abnormality or normality with the damage is a matter of research. Knowing whether median nerve somatosensory evoked potential (SEP) is useful in revealing subclinical damage in patients with Chiari malformation is important in the treatment and follow-up plan of the disease. The aim of this study was to investigate the relationship between median nerve SEP values and the severity of cerebellar ectopia in patients with Chiari type 1 malformation. Median nerve SEP values were obtained from 30 healthy individuals and 146 individuals with Chiari malformation. The cerebellar ectopia degree and McRae line length were measured. SEP values were not significantly different between groups. The McRae line was found to be significantly shorter in the control group than in the Chiari malformation group (p = 0.031). There was no correlation between the degree of cerebellar ectopia and the length of the McRae line (r = 0.002, p = 0.979). Neither cerebellar ectopy degree nor McRae line length had a relationship with SEP values (r = -0.153, p = 0.066;r = -0.056, p = 0.500, respectively). There was no difference in cerebellar ectopy degree or SEP values between the groups with cerebellar ectopy with and without a syrinx (p = 0.899;p = 0.080, respectively). Likewise, McRae line length was not found to be related to the presence of a syrinx (p = 0.139). Median nerve SEP examination was not beneficial for diagnosing asymptomatic-oligosymptomatic Chiari malformation as a subclinical injury, whether accompanied by syringomyelia or not.

Prognosis in prolonged coma patients with diffuse axonal injury assessed by somatosensory evoked potential

A total of 43 prolonged coma patients with diffuse axonal injury received the somatosensory evoked potential examination one month after injury in the First Affiliated Hospital, School of Medicine, Zhejiang University in China. Somatosensory evoked potentials were graded as normal, abnormal or absent （grades I-III） according to N20 amplitude and central conduction time. The outcome in patients with grade III somatosensory evoked potential was in each case unfavorable. The prognostic accuracy of grade III somatosensory evoked potential for unfavorable and non-awakening outcome was 100% and 80%, respectively. The prognostic accuracy of grade I somatosensory evoked potential for favorable and wakening outcome was 86% and 100%, respectively. These results suggest that somatosensory evoked potential grade is closely correlated with coma severity and degree of recovery. Somatosensory evoked potential is a valuable diagnostic tool to assess prognosis in prolonged coma patients with diffuse axonal injury.

Monitoring somatosensory evoked potentials in spinal cord ischemia-reperfusion injury

It remains unclear whether spinal cord ischemia-reperfusion injury caused by ischemia and other non-mechanical factors can be monitored by somatosensory evoked potentials. Therefore, we monitored spinal cord ischemia-reperfusion injury in rabbits using somatosensory evoked potential detection technology. The results showed that the somatosensory evoked potential latency was significantly prolonged and the amplitude significantly reduced until it disappeared during the period of spinal cord ischemia. After reperfusion for 30-180 minutes, the amplitude and latency began to gradually recover; at 360 minutes of reperfusion, the latency showed no significant difference compared with the pre-ischemic value, while the somatosensory evoked potential amplitude in- creased, and severe hindlimb motor dysfunctions were detected. Experimental findings suggest that changes in somatosensory evoked potentia~ ~atency can reflect the degree of spinat cord ischemic injury, while the amplitude variations are indicators of the late spinal cord reperfusion injury, which provide evidence for the assessment of limb motor function and avoid iatrogenic spinal cord injury.

Evaluation of degree of nerve root injury by dermatomal somatosensory evoked potential following lumbar spinal stenosis

BACKGROUND： Computed Tomography （CT） and Magnetic Resonance Imaging （MRI） can display the site of lumbar spinal stenosis and predict nervous compression at the morphological level; however, pure morphological changes cannot reflect functional alterations in a compressed nerve root. Dermatomal somatosensory evoked potential （DSEP） provides a means to assess the functional state of a nerve root. OBJECTIVE： To evaluate the clinical significance of DSEP, assessing the degree of nerve root injury following lumbar spinal stenosis. DESIGN, TIME AND SETTING： A case-control study was performed in the Department of Orthopaedic Surgery, Hainan People＇s Hospital, China, between September 2004 and December 2007. PARTICIPANTS： Forty-seven patients diagnosed with lumbar spinal stenosis by CT or MRI were selected as the case group; fifty healthy subjects were collected as the control group. METHODS： A KEYPOINT myoelectric evoked potential apparatus （DANTEC Company, Denmark） was used to measure DSEP, and stimulative spots were determined in accordance with the skin key sensory spot standards established by The American Spinal Injury Association： L4 in the medial malleolus, L5 in the third metatarsophalangeal joint of the dorsum of foot and S1 in the lateral heel. The needle electrode used as the recording electrode was located at the Cz point of the cranium, and the reference electrode at the Fz point. MAIN OUTCOME MEASURES： Latency of the P40 peak of DSEP, P1-N1 amplitude, P40 waveform and differentiation and disappearance of various waves. RESULTS： The sensitivity and diagnostic concurrence with surgery of nerve root injury following lumbar spinal stenosis evaluated by DSEP was 95.7 %. P40 latencies at L4, L5 and S1 in the case group were significantly longer than in the control group （P 〈 0.05）, and the P1-N1 amplitude in the case group was significantly lower than the control group （P 〈 0.05-0.01）. Nerve root injury was categorized according to DSEP latency as follows： severe damage （disappearance of the P40 wave in 103 dermatomes）, moderate damage （prolongation of the P40 peak latency ≥ 3.0 times the standard deviation of the normal mean in 60 dermatomes） and mild damage （prolongation of the P40 peak latency ≥ 2.5 times the standard deviation of the normal mean in 31 dermatomes）. CONCLUSION： DSEP can be used to determine the severity of nerve root injury following lumbar spinal stenosis with high sensitivity and specificity.

Cortical evoked potential changes in a rat model of acute ischemic stroke Detection of somatosensory evoked potential and motor evoked potential

BACKGROUND： Studies have shown that latency changes of some elements in a somatosensory evoked potential （SEP） and motor evoked potential （MEP） can reflect electrical activity of cerebral cortical neurons and conduction of white matter nerve fibers. However, there is a paucity of information regarding the dynamic observation of SEP and MEP following cerebral ischemic injury. OBJECTIVE： To explore SEP and MEP changes following acute ischemic stroke, and investigate the role of evoked potentials in monitoring brain function in stroke. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Chongqing Key Laboratory of Neurology, Affiliated Hospital of Chongqing Medical University from September 2007 to August 2008. MATERIALS＂ Hydrogen blood flow detector was purchased from Soochow University Medical Instrument Co., China, and Power lab system was purchased from AD Instruments, Inc., USA. METHODS A total of 36 healthy, adult, male, Sprague Dawley rats were randomly assigned to four groups （n = 9）, including three ischemia groups （12, 24 and 72 hours of ischemia） and a sham-surgery group. The rat model of acute ischemic stroke was established by middle cerebral artery occlusion （MCAO） in the left hemisphere. MAIN OUTCOME MEASURES＂ SEP and MEP of the left limbs were detected, and cerebral blood flow was measured by the hydrogen cleaning method. RESULTS： The latency of positive wave 1 （P1）, negative wave 1 （N1） and positive wave 2 （P2） waves in SEP, and latency of negative wave 1,2 （N1, N2） waves in MEP were significantly prolonged with increasing ischemic duration following MCAO （P 〈 0.01）, but cerebral blood flow was significantly decreased （P 〈 0.05, or P 〈 0.01）. CONLUSION： Ischemic stroke prolongs the latency of SEP waves （P1, N1, P2） and MEP waves （N1, N2）, and cerebral cortical evoked potential may correlate with cerebral blood flow changes. This indicates that SEP and MEP can be used to evaluate brain function following acute ischemic stroke.

Effects of ligustrazine on somatosensory evoked potential in normal rabbits and rabbits with cerebral ischemia-reperfusion injury

BACKGROUND： Somatosensory evoked potential （SEP） has become a method with higher sensitivity and specificity than electroencephalogram in detecting the brain function and the region, range and degree of ischemia. However, the effects of ligustrazine on SEP is still not clear. OBJECTIVE ： To study the protective effects of ligustrazini injection on cerebral ischemia-reperfusion injury.DESIGN： Auto-control study, random grouping.SETTING： Qilu Hospital of Shandong University.MATERIALS： The experiment was completed in the Cerebral Functional Room of Qilu Hospital Affiliated to Shandong University from March 2002 to June 2004. A totally of 24 healthy Harbin rabbits were randomly divided into blank control group （n=8）, model control group （n=8） and ligustrazine treatment group （n=8）. Hydrochloric ligustrazine injection, 40 mg/2 mL each ampoule, was provided by the Third Pharmaceutical Factory of Beijing （certification： 93035236273）. The main component was hydrochloric ligustrazine and the chemical name was 2, 3, 5, 6-tetramethyl pyrazine hydrochloride. METHODS：① Modeling method： The bilateral common carotid artery ligation was adopted to make the model. ② Index of cerebral functional lesion evaluated with SEP during ischemia-reperfusion： DISA 2000C neuromyoeletrometer provided by Dantec Electronics Ltd, Denmark was used to detect SEP. ③ Interventional process： Blank control group： The latencies and amplitudes of SEP were measured before injection with 1.5 mg/kg ligustrazine and at the points of 15 minutes, 20 minutes, 30 minutes, 60 minutes, 90 minutes and 120 minutes after injection. Ligustrazine treatment group： Rabbits were injected with 1.5 mg/kg ligustrazine, and those of model control group were injected the same volume of saline. Thirty minutes later, the bilateral common carotid artery of the rabbits all had been ligated for 30 minutes, and then reperfused for 120 minutes. The latencies and amplitudes of SEP were measured before injection, before ligation, at the points of 1 minute, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes and 30 minutes after ligation, and at the points of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 60 minutes, 90 minutes and 120 minutes after reperfusion.④ Evaluating criteria： Normal values of P-wave latencies and amplitudes were （19.34±3.18） ms and （4.55±1.43）μV. Average value before injection in blank control group and average values before injection, after injection and before ligation in ischemiareperfusion group were regarded as control criteria to evaluate changes of P-wave latencies and amplitudes after experiment. MAIN OUTCOME MEASURES： P-wave latencies and amplitudes of SEP in the three groups.RESULTS ： A total of 24 rabbits were involved in the final analysis without any loss.① Blank control group： The P-wave latencies delayed markedly at each time point after injection. Compared with that before injection, there was a significant difference （P 〈 0.05-0.01）. The P-wave amplitudes did not fluctuate noticeably all the time after injection, but significantly decreased when compared with those before injection （P 〈 0.05-0.01）. ② Ischemia-reperfusion group： The P-wave latencies delayed and amplitudes decreased in the rabbits with cerebral ischemia-reperfusion at all points of time during cerebral ischemia-reperfusion, and there was significant difference when compared with the levels before ischemia （P 〈 0.05）. When ligustrazine was injected, the latencies and amplitudes changed less, and as compared with the levels before ischemia, the difference was not significant （P〉 0.05）.CONCLUSION：① Ligustrazine can inhibit P-wave latencies and amplitudes of SEP of normal rabbits.②Ligustrazine can improve P-wave latencies and amplitudes of SEP of rabbits with cerebral ischemia-reperfusion injury.

A translational study of somatosensory evoked potential time–frequency components in rats,goats,and humans

Somatosensory evoked potentials(SEPs)have been widely used to assess neurological function in clinical practice.A good understanding of the association between SEP signals and neurological function is helpful for precise diagnosis of impairment location.Previous studies on SEPs have been reported in animal models.However,few studies have reported the relationships between SEP waveforms in animals and those in humans.In this study,we collected normal SEP waveforms and decomposed them into specific time–frequency components(TFCs).Our results showed three stable TFC distribution regions in intact goats and rats and in humans.After we induced spinal cord injury in the animal models,a greater number of small TFC distribution regions were observed in the injured goat and rat groups than in the normal group.Moreover,there were significant correlations(P<0.05)and linear relationships between the main SEP TFCs of the human group and those of the goat and rat groups.A stable TFC distribution of SEP components was observed in the human,goat and rat groups,and the TFC distribution modes were similar between the three groups.Results in various animal models in this study could be translated to future clinical studies based on SEP TFC analysis.Human studies were approved by the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster(approval No.UM 05-312 T/975)on December 5,2005.Rat experiments were approved by the Committee on the Use of Live Animals in Teaching and Research of Li Ka Shing Faculty of Medicine of the University of Hong Kong(approval No.CULART 2912-12)on January 28,2013.Goat experiments were approved by the Animal Ethics Committee of Affiliated Hospital of Guangdong Medical University(approval No.GDY2002132)on March 5,2018.

Changes in somatosensory evoked potentials elicited by stimulation of upper-limb and lower-limb nerves in amyotrophic lateral sclerosis patients

This study observed the changes in somatosensory evoked potentials between patients with amyotrophic lateral sclerosis （ALS） and healthy controls to evaluate the function of the central deep somatosensory pathway. In patients with ALS, 28 patients （54%） showed an abnormality in somatosensory evoked potentials. All had abnormal lower limb somatosensory evoked potentials. Compared with healthy controls, the abnormality in somatosensory evoked potential was characterized by prolonged N20, P2, N2 latency and central conduction time, with or without a decrease in wave amplitude or disappearance of waveform. Results showed marked alterations in the somatosensory evoked potential in cortical components of the upper and lower limb in 54% of patients with ALS, and confirmed that patients with ALS may also have a defective deep somatosensory pathway, particularly an abnormal central deep somatosensory pathway.

Determination of Median Nerve Somatosensory Evoked Potentials in 27 Patients with Hemiplegia

Summary: Twenty-seven in-patients with hemiplegia following brain injury were studied by using upper extremity median nerve somatosensory evoked patentials (SVEP), Brunnstrom assessment in hemiplegic hand and assessment of the patients' activities of daily lioing (ADL) (Barthel index). The upper extremity median nerve SEP on the affected and normal sides was determined. By using Kovindha standard, upper extremity median nerve SEP was graded in accordance with N20. The correlation between the differences of SEP N20 amplitude and the latencies on the both sides and the Barthel index scores was analyzed. A Spearman correlation analysis was made between the median nerve SEP N20 grades and Brunnstrom stages in hand or ADL on the affected side. The results showed that upper extremity median nerve SEP grades were positively correlated with those of the Brunnstrom stages in hand (r 1=0.6925, P 1<0.01). The correlation coefficient between SEP N20 grades and patients' ADL grades was r 2=0.5015, P 2<0 01. It was concluded that upper extremity median nerve SEP could be used as a sensitive electrophysiological predictor to clinically assess hemiplegic hand function. SEP N20 might play a role in predicting the ADL of the patients with hemiplegia to some extent, but could not be used as a sensitive predictor to directly observe and predict the ADL of the patients.

Dermatomal Somatosensory Evoked Potentials: An Indicator of Improvement of Breast Sensibility after Reduction Mammaplasty

Introduction: Many women think about reduction mammaplasty for different reasons. The effect of surgery on the beast sensibility is one of the greatest concerns after reconstructive reductive breast surgery through its affect on patient’s social life and psychological health. The dermatomal somatosensory evoked potential (D-SEP) is a new method to quantitatively evaluate breast sensibility. Patients and Methods: Twenty-five women enrolled in this study presenting with breast enlargement, underwent mammary reduction by using the inferior pyramidal breast reduction technique using the same operative technique described by Robbins with some modifications. All D-SEP amplitudes and latencies were calculated preoperatively and then were reassessed six and twelve months post-surgery in each breast. Result: The results revealed that there is a significant difference in the D-SEP latency pre- and post-operatively. The statistically significant decrease in latency and the breast size demonstrated indicates that the sensibility improved after breast reduction surgery both at six and twelve months. There is also a significant increase in the D-SEP amplitude pre- and post-operatively. The negative and statistically significant increase in amplitude with the decrease in breast size demonstrated indicates that the sensibility improved after breast reduction surgery both at six and twelve months. Conclusion: This study concluded that breast sensibility will improve after breast reduction as indicated by significant reduction of D-SEP latencies and increase of its amplitudes. Our results confirm an inverse relationship between breast size and sensibility, with improvement in sensibility after breast reduction.

Identification of injury type using somatosensory and motor evoked potentials in a rat spinal cord injury model

The spinal cord is at risk of injury during spinal surgery.If intraoperative spinal co rd injury is identified early,irreve rsible impairment or loss of neurological function can be prevented.Different types of spinal cord injury result in damage to diffe rent spinal cord regions,which may cause diffe rent somatosensory and motor evoked potential signal res ponses.In this study,we examined electrophysiological and histopathological changes between contusion,distra ction,and dislocation spinal cord injuries in a rat model.We found that contusion led to the most severe dorsal white matter injury and caused considerable attenuation of both somatosensory and motor evoked potentials.Dislocation resulted in loss of myelinated axons in the lateral region of the injured spinal cord along the rostrocaudal axis.The amplitude of attenuation in motor evoked potential responses caused by dislocation was greater than that caused by contusion.After distraction injury,extracellular spaces were slightly but not significantly enlarged;somatosensory evoked potential res ponses slightly decreased and motor evoked potential responses were lost.Correlation analysis showed that histological and electrophysiological findings we re significantly correlated and related to injury type.Intraope rative monitoring of both somatosensory and motor evoked potentials has the potential to identify iatrogenic spinal cord injury type during surgery.

Value of somatosensory evoked potentials in diagnosis, surgical monitoring and prognosis of cervical spondylotic myelopathy

Background The value of somatosensory evoked potentials （SEPs） in the diagnosis and prognosis of cervical spondylotic myelopathy, as well as the usefulness of monitoring intraoperative potentials in terms of safety and predictive factors were investigated. Methods Each of the 76 myelopathic patients underwent surgical intervention. According to the wave configurations of the SEPs, the cases were categorised into four groups： Type Ⅰ, Ⅱ, Ⅲ and Ⅳ. The clinical myelopathy disability was classified and the severity of neurological deficits was scored. Clinical function after surgery was evaluated. Preoperative potentials and intraoperative monitoring were categorized. The correlations between .evoked potentials detection, monitoring, myelopathy disability and surgical outcome in the different groups were discussed. Results According to the configurations of the SEPs, there were 27 patients （36%） of Type Ⅰ, 30 patients （39%） of Type Ⅱ, 8 patients （11%） of Type Ⅲ, and 11 patients （14%） of Type Ⅳ. The categorised evoked potentials were shown to be significantly associated with the clinical representation of myelopathy （P 〈0.01） and the recovery rate from identifiable SEPs waves （groups A, B and C） was significantly higher than unidentifiable waves （group D, P〈0.01）. A deterioration of SEPs was detected in 23 cases （30%）, whereas there was no change in 40 cases （53%） and improvements in 13 cases （17%）. A significant difference in recovery rates could be observed in various monitoring groups within the short-term follow-up period, while there were no obvious differences in the long-term follow-up groups. Conclusions SEP technique is a valuable and practical tool for the diagnosis, monitoring and prognosis of myelopathy. Classified evoked potentials are well correlated with cervical spondylotic myelopathy disability, and unidentifiable SEPs waves in patients are indicative of a relatively poor outcome. In addition, intraoperative monitoring of SEPs plays an important role in protecting neural structures during cervical spine surgery.

Effect of renewed SS-cream on spinal somatosensory evokedpotential in rabbits

Aim: The effect of a renewed SS-cream (RSSC) on the treatment of premature ejaculation (PE) was evaluated and compared with the original SS-cream (OSSC). Methods: Sixty male white New Zealand rabbits, weighing 2.5kg-3.0 kg, were divided at random into 3 groups: the RSSC, OSSC and placebo groups. The spinal somatosensory evoked potential (SSEP) elicited by electric stimulation of the glans penis with disk electrode was investigated with an electrophysiograph (Poseidomn, Shanghai, China) before and 10, 30 and 60 min after drug or placebo application on the glans. The Onset and the N1 latencies and the amplitude of SSEP were recorded and analyzed. Results: There was no significant difference (P>0.05) in the mean Onset and Nl latency of SSEP among the 3 groups before drug application. Compared with the pre-application value, the mean Onset and Nl latencies in the RSSC and OSSC groups were significantly prolonged at 10, 30 and 60 min after treatment (P<0.05), while they were not significantly changed (P>0.05) in the placebo group. The mean Onset latency of RSSC at 10 and 30 min and that of OSSC at 30 min were significantly delayed (P<0.05) compared with the placebo group. The mean Nl latency of RSSC at 30 and 60 min and that of OSSC group at 30 min were also significantly delayed (P<0.05). Conclusion: RSSC delays the latencies of SSEP, suggesting a local desensitizing effect on the sensory receptor of the glans penis dorsal nerve, which provides the potential for PE treatment. The desensitizing effect of RSSC is higher than that of OSSC.

Reliability of dermatomal somatosensory-evoked potential in the evaluation of lumbosacral nerve root injury A concurrent case-control study

BACKGROUND： It has been reported that dermatomal somatosensory evoked potential （DSEP） can be used for diagnosing nerve root injury in patients with lumbar disc herniation （LDH）, and that 83% 95% of patients suffer from the disease. Body height correction is not performed prior to determinations of latency and latency difference between the healthy and affected sides. However, latency noticeably correlates to body height. OBJECTIVE： This study aims to determine the lumbosacral nerve root injury in patients with LDH by DSEP, and to evaluate the sensitivity of the DSEP difference between the healthy and affected sides using a diagnostic index following body height correction. DESIGN： A case-control observation. SETTING： Department of Orthopedic Surgery, Hainan Provincial People＇s Hospital. PARTICIPANTS： Ninety-six patients, comprised of 67 males and 29 females, with an average age of 43 years and a mean body height of 1.65 m （range 1.48-1.81 m）, were recruited for this study. These patients suffered from unilateral lower limb radiation pain and received treatment at the Department of Orthopedic Surgery, Hainan Provincial People＇s Hospital between January 2004 and December 2006. All patients were confirmed to suffer from LDH at the L3-4, L-5, and/or Ls-SI by CT and/or MRI examinations. Central nervous system diseases were excluded. In order to obtain a normal reference value, DSEP was determined for a group of 50 subjects, who concurrently received health examinations in the same department. The subjects had no previous history of back leg pain or nervous system disease. The group of healthy controls included 26 males and 24 females, with an average age of 37 years and a mean body height of 1.63 m （range 1.50-1.80 m）. Written informed consent was obtained from all subjects for laboratory samples. The protocol was approved by the Hospital＇s Ethics Committees. DSEP was determined with myoelectricity-evoked potential equipment （Keypoint, Batch No. 9020A0042591, Dantec Company, Denmark）. METHODS： DSEP of patients with LDH was determined. Constant-voltage square pulse stimulation was used to determine DSEP, with the following parameters： a pulse wave width of 0.2 milliseconds; a saddle-like stimulating electrode; a stimulation intensity 3 times greater than the sensation threshold; a stimulation frequency of 1.5 Hz; mean superposition greater than 100 times; and inter-electrode impedance 〈 5 k Q. The stimulation point was a skin key sensation point confirmed by the American Spinal Injury Association, i.e. L4 at medial malleolus, L5 at the third metatarsophalangeal joint on the dorsum of the foot, and SI at the lateral heel. The recording electrode was a needle electrode, the recording point was Cz, and the reference electrode was Fz. DSEP latency of P40, and latency differences of P40, between the healthy side and the affected side, were determined. DSEP at L4, L5, and S1 nerve roots of the lower limbs of 50 healthy controls were bilaterally determined. The normal values of P40 latency and P40 N50 amplitude were statistically obtained. MAIN OUTCOME MEASURES： Determination of DSEP values. RESULTS： Ninety-six patients with LDH and fifty healthy controls participated in the final analysis. In the healthy controls, the amplitude of DSEP varied greatly, with a mean amplitude co-efficient of variation of 58% for L4, L5, and SI dermatomes. P40 latency was stable, with a mean latency coefficient of variation of 4.7%. In patients with LDH, the P40 wave disappeared. P40 latency was 2.5 times prolonged compared to normal mean value. P40 latency difference between the healthy and the affected side was 2.5 times higher than the normal mean value of the healthy side. CONCLUSION： DSEP can reflect the functional status of lumbosacral nerve root. P40 latency difference between the healthy side and the affected side is the most sensitive diagnosis index for patients with LDH suffering from unilateral lower limb radiation pain.

APPLICATION OF PRE－AND POSTOPERATIVE SOMATOSENSORY EVOKED POTENTIALS OF DIASTEMATOMYELIA

Conical somatosensory evoked potential(CSEP) examination of posterior tibial nerve was performed Pre-and postoperatively smong 20 patients with diastematomyelia and 20 normal people as control group at the same time.The results indicated CSEP changes were statistically significant between patients and normal people(P< 0.05);postoperative P40, Peak latencies and amplitudes changed significantly and CSEPs had apparent difference in bilateral lower extremities among preoperative patients.This shows that CSEP is an objective,sensitive and reliable diagnostic tool that may be used to judge the severity of neural damage and evaluate the surgical results.

THE SIGNIFICANCE OF DERMATOMAL SOMATOSENSORY EVOKED POTENTIALS IN THE DIAGNOSIS OF LUMBOSACRAL NERVE ROOT COMPRESSION

in this study, conical somatosensory evoked potentials (SEPs)following electrical stimulation of the skin of LS and SI dermatomes were recorded cephalically and observed in 19 patients with clinically proved unilateral L5 or S1 nerve root compression, and the results were compared with those of the control group or 20 healthy volunteers and showed that dermatomal SEPs were abnormal in 12 with the rate of 63%,most or which showed abnomalities or the lateral latency difference. It is concluded that dermatomal SEP is a useful addition to the diagnosis or lumbosacral nerve root compression. When the unilateral nerve root is compressed the lateral latency dirference is a most sensitive criterion for indicating abnomality.

Acute spinal subdural haematoma complicating a posterior spinal instrumented fusion for congenital scoliosis:A case report

BACKGROUND Acute spinal subdural haematoma(ASSH)is a rare and potentially devastating condition with a variable prognosis.Previously described subdural haematomas were thought to have occurred spontaneously or be related to major or minor iatrogenic or traumatic injuries caused by surgery,spinal puncture or epidural anaesthesia.Other contributing pathologies have been described,such as intradural tumours or spinal arteriovenous malformations.ASSH has also been associated with anticoagulation therapy,haemostatic abnormalities and risk factors such as pregnancy.To the best of our knowledge,this case study described the first reported occurrence of an ASSH during spinal surgery in a paediatric patient.The patient was not known to have any coagulopathies,and no obvious vascular lesions were documented.The surgical procedure did not directly involve the dura mater,and no evident intraoperative dural tears were found.CASE SUMMARY We reported and discussed a case of ASSH complicating a posterior spinal instrumented fusion during surgery for paediatric congenital scoliosis.This condition has not been previously described.We made recommendations for facing such an occurrence,explored its aetiology in the context of malformation and discussed the benefits of neuromonitoring during scoliosis correction and the management protocol.We conducted a PubMed literature review for cases of paediatric ASSH and other closely related disorders.We reviewed recommendations regarding neuromonitoring and treatment management in such cases.CONCLUSION ASSH is a rare complication of posterior spinal instrumented fusion.Published cases are more often associated with anticoagulation therapy or coagulopathy.Neuromonitoring is strongly recommended to detect and assess neurological status,thus enabling rapid diagnosis and treatment and facilitating early spinal decompression and a return to a normal neurological status.

Human umbilical cord blood stem cell transplantation for the treatment of chronic spinal cord injury Electrophysiological changes and long-term efficacy

Stem cell transplantation can promote functional restoration following acute spinal cord injury （injury time 〈 3 months）, but the safety and long-term efficacy of this treatment need further exploration. In this study, 25 patients with traumatic spinal cord injury （injury time 〉 6 months） were treated with human umbilical cord blood stem cells via intravenous and intrathecal injection. The follow-up period was 12 months after transplantation. Results found that autonomic nerve functions were restored and the latent period of somatosensory evoked potentials was reduced. There were no severe adverse reactions in patients following stem cell transplantation. These experimental findings suggest that the transplantation of human umbilical cord blood stem cells is a safe and effective treatment for patients with traumatic spinal cord injury

Combined monitoring of evoked potentials during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms

Background Neurophysiologic monitoring during surgery is to prevent permanent neurological injury resulting from surgical manipulation. To improve the accuracy and sensitivity of intraoperative neuromonitoring, combined monitoring of transcranial electrical stimulation motor evoked potentials （TES-MEPs）, somatosensory evoked potentials （SSEPs） and brainstem auditory evoked potentials （BAEPs） was attempted in microsurgery for lesions adjacent to the brainstem and intracranial aneurysms. Methods Monitoring of combined TES-MEPs with SSEPs was attempted in 68 consecutive patients with lesions adjacent to the brainstem as well as intracranial aneurysms. Among them, 31 patients （31 operations, 28 of posterior cranial fossa tumors, 3 of posterior circulation aneurysms） were also subjected to monitoring of BAEPs. The correlation of monitoring results and clinical outcome was studied prospectively. Results Combined monitoring of evoked potentials （EPs） was done in 64 （94.1%） of the 68 patients. MEPs monitoring was impossible for 4 patients （5.9%）. No complication was observed during the combined monitoring in all the patients. In 45 （66.2%） of the 68 patients, EPs were stable, and they were neurologically intact. Motor dysfunction was detected by MEPs in 8 patients, SSEPs in 5, and BAEPs in 4, respectively. Conclusions A close relationship exists between postoperative motor function and the results of TES-MEPs monitoring TES-MEPs are superior to SSEPs and BAEPs in detecting motor dysfunction, but combined EPs serve as a safe, effective and invasive method for intraoperative monitoring of the function of the motor nervous system. Monitoring of combined EPs during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms may detect potentially hazardous maneuvers and improve the safety of subsequent procedures.

Effect of electrical stimulation on neural regeneration via the p38-RhoA and ERK1/2-Bcl-2 pathways in spinal cord-injured rats

Although electrical stimulation is therapeutically applied for neural regeneration in patients, it remains unclear how electrical stimulation exerts its effects at the molecular level on spinal cord injury （SCI）. To identify the signaling pathway involved in electrical stimulation improving the function of injured spinal cord, 21 female Sprague-Dawley rats were randomly assigned to three groups： control （no surgical intervention, n = 6）, SCI （SCI only, n = 5）, and electrical simulation （ES; SCI induction followed by ES treatment, n = 10）. A complete spinal cord transection was performed at the 10^th thoracic level. Electrical stimulation of the injured spinal cord region was applied for 4 hours per day for 7 days. On days 2 and 7 post SCI, the Touch-Test Sensory Evaluators and the Basso-Beattie-Bresnahan locomotor scale were used to evaluate rat sensory and motor function. Somatosensory-evoked potentials of the tibial nerve of a hind paw of the rat were measured to evaluate the electrophysiological function of injured spinal cord. Western blot analysis was performed to measure p38-RhoA and ERK1/2-Bcl-2 pathways related protein levels in the injured spinal cord. Rat sensory and motor functions were similar between SCI and ES groups. Com- pared with the SCI group, in the ES group, the latencies of the somatosensory-evoked potential of the tibial nerve of rats were significantly shortened, the amplitudes were significantly increased, RhoA protein level was significantly decreased, protein gene product 9.5 expression, ERK1/2, p38, and Bcl-2 protein levels in the spinal cord were significantly increased. These data suggest that ES can promote the recovery of electrophysiological function of the injured spinal cord through regulating p38-RhoA and ERK1/2-Bcl-2 pathway-related protein levels in the injured spinal cord.