| Background:With the rapid development of transportation,construction and mining industry,the number of patients withspinal cord injury in our country increases significantly inrecent years.Due to spinal cord injury,functions of body tendto waste obviously,the quality of life in patients decreasesand serious domestic social problems are produced with it.Theprevention and treatment of this disease has always been hotand difficult in medical community.With today’s extremelyrapid development of medicine,research on the treatment ofspinal cord injury have lasted for several centuries.But forthe diagnosis and treatment of spinal cord injury,there arestill many different views,such as the degree judgment ofspinal cord injury,treatment,and prognosis judgment of it.Inthe surgical treatment of spinal cord injury,academic pointsof view are not the same,in which the spinal cord decompressionafter injury is still the focus of debate.The main problemsinclude how to determine the specific degree of injury,theeffectiveness of different methods of decompression,how to select specific methods and how to determine time ofdecompression.At present,imaging diagnosis,neurologicalexamination and personal experience are applied in judgment.Evoked potentials(EPs) technology which belongs toneurophysiological examination can monitor the changes ofneurological function in real time.With a large number ofapplications and the development of the technology,it isexpected to provide an objective and specific support forsolving these problems.Subjective:This study aims at investigating the guidingsignificance of different surgical decompression methods afterspinal cord injury by observing the changes of somatosensoryevoked potentials in acute spinal cord injury rats whichrespectively applied laminectomy,durotomy and myelotomy.Methods:In animal experiments,Wistar rats were randomlydivided into A, B, C three large groups,12rats were includedin each large group.Every large group is divided into twosubgroups,one without spinal cord injury,another one withspinal cord injury.6rats were included in each subgroup.Onerat in each subgroup was made for pathological section of spinalcord specimens to observe changes of spinal cord afterinjury.Group A was called as laminectomy group;Group B durotomy group;Group C myelotomy group.1%pentobarbital byintraperitoneal injection (5ml/kg)was used for anesthesia.Ingroup A,rats were operated by T9,T10laminectomy afteranesthesia and then were grouped:①no damage group: notreatment;②injury group:Allen’s spinal cord injury modelapproach was applied.We use a self-made device and make a weightof5g freely fall from heights of20cm,causing trauma of5g×20cm=100g· cm potential strength.In group B,thecorresponding segments of the spinal cord were fully exposedand then were grouped:①no damage group:Using a sharp syringeneedle lightly pierced the spinal cord meninges layer;②injurygroup:Using a sharp syringe needle lightly pierced the spinalcord meninges layer in ten minutes after spinal cord hit.Ingroup C,the corresponding segments of the spinal cord werefully exposed and then were grouped:①no damage group:Cuttingthe spinal cord to the central tube position with a sharp knifealong the longitudinal direction along the dorsal local mediansulcus on surface of the spinal cord;②injury group:The samemethod was carried out in ten minutes after spinal cord hit.Finally,rat model of acute spinal cord injury of differentdegrees were made and three surgical decompression were appliedafter injury.In our experiment,first we observe latency and amplitude of CSEP at different stimulus intensity in group Awithout spinal cord injury to determine the optimal stimulationintensity.Second,we observe changes of CSEP latency andamplitude after anesthesia,after laminectomy to observe andexclude the possible elements which affect the experimentalresults during surgery.Last,latency and amplitude of CSEP weredetected and recorded in each group at the time ofanesthetized,spinal revealed,post operation,postoperative1day,3days,7days,15days.Evoked potentials were detected and recorded by DANTECKeypoint-portable-type2-channel evoked potential recordingdevices which is produced in Denmark and needle stimulation,recording electrode.How to record CSEP:insert the needlestimulation electrode negative in rat right hind leg lateralhead of the gastrocnemius muscle near the site peronealnerve,stimulating electrode positive is inserted from thenegative about0.8cm at the distal direction;recordingelectrode(black) is placed in the lower left quadrant of brainsensory cortex area intersection between the skull midline andthe ears root leading edge;reference electrode(red) is placedunder the hard palate mucosa of rat;ground electrode(green) isplaced subcutaneously on back of rat(between stimulating electrode and recording electrode).Stimulate the peronealnerve with continuous pulse and record CSEP on somatosensorycortex.Statistical analysis was applied for all the results.Results:Evoked potential were monitored in all rats afteranesthesia and ideal waveforms were received.CSEP normalwaveforms we detected in rat peroneal nerve were mostly “N”or similar “N” shape.For inability of nerveelectrophysiological data before anesthesia in rats,our studyrecord neurophysiological data after conventional sodiumpentobarbital anesthesia as the basic reference data.①Recordsof CSEP in each group after spinal anesthesia and spinal cordrevealed had no significant difference and the influence of theexperimental results can be eliminated in the surgicalprocedure.②In no injury groups,CSEP data were measured byrepeated measures analysis of variance.In group A(laminotomygroup),the variance of latency and amplitude had no significantdifference (P>0.05).In group B(meninges incision group),thevariance of latency and amplitude at each time had nosignificant difference(P>0.05).In group C(spinal incisiongroup),except post operation,the variance of latency andamplitude at each time had no significant difference(P>0.05).Variance of latency and amplitude after surgery compared with spinal cord revealed had significant difference(P<0.05).Threesurgical methods were compared by ANOVA test.Variance oflatency and amplitude after surgery between the three groupswere significantly different(P<0.05).There was no significantdifference on the other periods.It showed that latency extendedand amplitude decreased after spinal cord cut operation inmyelotomy group.③In injury group,CSEP data were measured byrepeated measures analysis.In each group of different surgicalmethods,the CSEP measured immediately after operation comparedto the spinal cord revealed had significant differences(P<0.05). And it showed no significant difference (P>0.05) atpostoperative15days compared to spinal cord revealed.One-wayANOVA test showed changes of latency of CSEP between three kindsof surgical methods had no significant difference(P>0.05).Thelatency in Group A compared with Group B, C had significantdifference(P<0.05).During the experiment,we found that CSEPdata were different in individual rats,but the consistency wasgood.Conclusion:1.Vice damage of spinal in Myelotomy operation would beeasily produced.However,restoration situation of the damagewas optimistic. 2.After spinal cord injury,applications of Laminectomy,Durotomy and Myelotomy treatments had no significantdifference. |
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