The Clinical And Experimental Study Of Correlation Between Pathogenesis Of Postoperative Neurologic Complication After Cervical Spondylotic Myelopathy Treated By Decompression And The System Of Peripheral Passageway In Cervical Cord

Objective To investigate the relationship between the etiology of postoperativeneurology complications for cervical compressive myelopathy by differentdecompression approach and certain pathways in cervical cord.Describe the pathwayand projection originated from motor or sensory propriospinal neurons composed ofcervical nerve roots.Discuss distribution and function of propriospinal neurons andpropriospinal tracts in central nervous system.Methods (1)clinical study(retrospective analysis):The study population comprised 297 patients with whounderwent decompression surgery.Anterior decompression,fusion and internalfixation was performed in 126 cases who entirely resulted from cervical disc hernia,laminectomy in 171 cases (67cases who resulted from cervical disc hernia,104 caseswho resulted from ossification of posterior longitudinal ligament) .Neurologiccharacteristics of patients with postoperative upper extremity palsy were investigated.Relationships between the palsy and clinical manifestation,radiographic examinationand pathogenesis location were evaluated with chi-square test analysis.Postoperativeupper extremity palsy occurred in 37 cases in anterior approach,36 cases in posteriorapproach (9 cases who resulted from cervical disc hernia,27 cases who resulted fromossification of posterior longitudinal ligament).(2)selective anterior root retrogradelabelling on C8 and T1 right spinal roots of rats:80 adult SD rats were selected,1%Fluoro-gold and pseudorabies virus(PRV)were injected into anterior root(posteriorroot transsection),other right spinal roots which joined cervical enlargement wereabscised except target nerve roots.After 4hrs since the tracers were introduced,animals were executed,we employed a double-tracing strategy to discriminate centralprojection of primary or multilevel motor propriospinal neurons,besides,we alsoapplied double immunohistochemistry or immunofluoresence technique of PRV forfrozen sections,acetylcholine esterase stain was used to exclude motor neuronswithin target anterior horn,some samples were reacted with DAB before microscopicobservation,the researchers recorded location and counts of positive nerve fibers andneurons.All data were processed with statistical treatment.(3)after cutting off targetanterior root and other right spinal roots which joined cervical enlargement of 40 adult SD rats,we employed the method of selective posterior root anterogradelabelling and Manganese-enhanced MRI to analyze central projections of sensorypropriospinal neurons in 10hrs after injection,simultaneously,utilizing e-filmsoftware to calculate area magnitude of positive nerve fibers and the distance fromperipheral rim to central canal.Results (1)After a follow-up period of3-Syears(average,4.2 years),all cases accompanied with postoperative neurologiccomplications were spontaneously rehabilitated within postoperative 2-6 months.Theincidence of distal palsy of upper extremity was fairly higher than that of proximalpalsy among anterior and posterior approach.There was not significant difference incomparison of constituent ratio of palsy patients and non-palsy patients betweenC2-C5 and C5-T1 segment regarding decompression range.A majority of sufferersaccompanied with postoperative expansion of high-signal intensity zone were moreliable to develop upper extremity palsy,however,abnormal signal on T 1-weightedimage did not occur on any case.Postoperative high-signal intensity zone for amajority of patients was found to significantly expand to adjacent segment orintervartebral levels along longitudinal axis.The difference in comparison of amountof increased cervical lordosis and cord shifting extent between palsy patients andnon-palsy patients did not reach statistic significance.(2)①selective retrograde oranterograde fasciculus tracing on C8 and T1 spinal nerve roots of 80 SDsprague-dawley rats:4 hrs after the tracers was injected,positively motorpropriospinal neurons could be observed in anterior horn (Ⅷ,Ⅸlayers) andintermediate zone of identical myelomere (C8 or Tlspinal cord) ,predominantlylocated in fundament of posterior horn and intermediate zone of C5 to C7myelomeres,chiefly situated in top,head,neck of posterior horn and intermediatezone of C3 to C4 myelomeres,primarily distributed in oppositely anterior horn fromC1 to C2 myelomeres.②motor propriospinal tracts could be observed inhomonymous anterior-lateral funiculus(close to anterior lateral sulcus) in samples ofC8 or T1 spinal cord,mostly concentrated on dorsal part of lateral funiculus andventral-lateral part of posterior funiculus from C5 to C7 segments,resided in ventralpart of bilateral lateral funiculus in C3～4 segments,chiefly distributed in oppositelyanterior funiculus in C1～2 sections;③Concerning the area size of motor propriospinalfasciculus,there was significant difference between bilateral sides inC1～2,C8 or T1 spinal cord,no significant differences could be observed amongC3～7(8) segments,however,as to the area dimension of fasciculus proprius,thedifference between bilateral sides only in C8 or T1 segment did reach statisticsignificance,the difference between bilateral sides in other segments did not reachstatistic significance;④The quantity of Non-primary motor propriospinal neurons inC3～4 myelomeres is largest,considerably larger in C1～2 myelomeres,fairly largerin C5～6 myelomeres,least in C7 spinal cord;⑤The amount of primarily motorpropriospinal neurons stained by fluorogold in C7 segment was much more than thatin other myelomeres,that in C8 or T1 less than that in C7,that in C5～6 less than thatin C8 or T1,that in C4 much less than that in C5～6;⑥motor propriospinal fasciculuswere extensively distributed in C3～4 myelomeres,those in C5～7 myelomeres lessthan those in C3～4,those in C8 or T1 less than those in C5～7,those in C1～2 lessthan those in C8 or T1;⑦sensory propriospinal tracts could be observed in thevicinity of homonymous posterior-lateral sulcus in C8 or T1 segments,mainlyconcentrated on ventral and intermedial part of bilateral lateral funiculus from C5 toC7 segments,localized in dorsal and middle part of bilaterally lateral funiculus inC3～4 segments,chiefly centralized in bilateral posterior-lateral funiculus in C1～2segments;⑧Partial overlapping could be observed in the region of ascending sensoryand locomotive fasciculus proprius which constituted of C8 and T1 spinal nerve roots,the distance between margin of sensory and locomotive fasciculus proprius and graymatter(central canal)of T1 nerve root was much farther than that of C8 spinal nerveroot in C1～7 segments.Conclusions (1)We should not generalize most discomfortafter surgery with the sequela of'palsy of Cervical 5or6 spinal root',the essence ofabove-mentioned symptoms may be the impairment of reversible and temporaryinflammation and reparation reaction on peripheral nerve passageway or pathwayrelated to lower motor neurons within cervical cord due to decompression process.Amoderate increase of cervical lordosis in anterior and posterior surgery and cordshifting in posterior approach should not induce the occurrence of postoperativecomplication;(2)The alteration tendency of high-signal intensity zone mayprognosticate occurrence of postoperative complications to comparatively large extent. The preliminary data of this study suggest a high incidence of upper extremity palsyin the patients with significant expansion of postoperative high-signal intensity zone;most narrowed intervertebral level or pathological segment generally presented byhigh-signal intensity zone as well as contiguous zone would be more easily involvedby harmfully operative procedure,The incidence and Severity extent of upperextremity palsy had no correlation with postoperative expansion and backwardshifting amplitude of cervical cord.(3)With the help of selective retrograde tractlabeling,we could distinguish and observe primary and non-primary associationneurons among propriospinal neurons;(4)To view distribution layout of sensory andlocomotive fasciculus proprius,these fibers which construct spinal nerve root ofsuperior position approach nearer to grey matter,vice versa,which is coincident withalignment of ascending fibers from different spinal segments in lateral corticospinaltract,Spinothalamic tract ,fasciculus gracilis,fasciculus cuneatus.(5)Spinal cordabove cervical 5 segment is the region in which propriospinal tracts affiliated toinferior nerve roots which construct cervical enlargement generally transit,integrateand group,decompression for the site above cervical enlargement may result inproximal or/and distal end of upper extremity palsy.(6) We employ nerve tracing todisclose that sequential facts:propriospinal neurons play a linkage role betweenmotor neurons located in anterior horn or sensory neurons located in posterior horn oftarget cervical segment and pathway system responsible to upper motor neurons,which make for information interchange,storage,integration and mediation amongspinal reflex.Fasciculus proprius which construct homonymous nerve root also gothrough opposite side of spinal cord,Motor fasciculus proprius accompanying longdescending tracts would terminate in lateral reticular nucleus and decussation ofpyramid,sensory fasciculus proprius accompanying long ascending tracts would endin ventral posterolateral nucleus of dorsal thalamus.