| Cervical disc degeneration is the basic pathology of degenerativecervical spondylosis. Cervical disc degeneration is always followed bydegeneration of uncovertebral joint and zygapophyseal joint, which oftenaffect vertebal artery. Thus it's necessary to study anatomical property fortransverse foramen and strctures closed to it.Anterior cervical decompression and fusion(ACDF) has become agolden standard management for cervical degenerative disease. HoweverACDF is regarded correlated to the changes of adjacent kinetics andstress distribution of intrvertebral disc and zygapophyseal joint,adjacent cervical segment degeneration happens thereafter. As analternative management to degenerated cervical disc, cervical artificialdisc replacement preserves motion at the instrumented levels andpotentially decrease degeneration rate of adjacent segment. Two-levelcervical artifical disc repacement (ADR) has been used primarily inclinic, However there is few report about biomechanics of two levelcervical artificial disc replacement, nor is experimental or clinical studyof comparisons of the effects of two level ADR, Anterior cervicaldiscectomy(ACD) and ACDF to inferior adjacent zygapophyseal joint,which is important in biomechanics and usually used to evaluate adjacentsegment degeneration degree post-operatively.The current study was undertaken to investigate in the followingthree parts: (1)measuring cervical transverse foramen and its relation toadjacent sturctures.(2)exploring the effect to stress ditribution of C5/6, C6/7zygapophyseal joint in cadaveric cervical specimens under variousloadings following ACD, ACDF and ADR at C4/5, C5/6 level. (3)observingthe clinical effects of ADR and ACDF at C4/5, C5/6 level and the relatedeffects at the adjacent zygapophyseal joint.CHAPTER ONE: Anatomical Measurement of Transverse ForamenObjectives: To measure transverse diameter and saggital diameterof transverse foramen and its relation to adjacent structures so as to provide reference of anatomy and morphology for the basis of clinicdiagonosis, surgical management for cervical spondylosis.Methods: 11 fresh cervical specimens of adult cadavers were usedthrough the CT scan and practical measurement to measure transversediameter and saggital diameter of the transverse foramen; positive andrelative distance between transverse foramen and uncovertebral joint;positive and relative distance between transverse foramen andzygapophyseal joint. One-Way ANOVA and Paired-Samples T Testwere used to detect significant changes of the difference in eachsegment.(α=0.05)Results: (1) there was no significant difference of the transversediameter and sagittal diameter between left and right transverse foramenfrom C1 to C7(P＞0.05). The diameter of C7 transverse foramen issmallest(P＜0.05). (2)there is no significant difference of positive distancebetween transverse foramen and uncovertebral joint from C3 to C7(P＞0.05), the relative distance between transverse foramen anduncovertebral joint of C3, C7 is larger than that of C4 to C6(P＜0.05);(3)there is no significant difference of positive distance betweentransverse foramen and zygapophyseal joint from C3 to C7(P＞0.05), therelative distance between transverse foramen and zygapophyseal joint ofC5, C6 is larger than that of C3, C4, C7(P＜0.05). There was no significantdifference between the values of measurement through CT scan andpractical measurement(P＞0.05).Conclusions: (1) there was no difference of the transverse diameterand sagittal diameter between left and right transverse foramen from C1to C7. the diameter of C7 transverse foramen is smallest. (2) the relativedistance between transverse foramen and uncovertebral joint of C4 to C6is small, transverse foramens from C4 to C6 are close to vertebral artery.(3)the relative distance between transverse foramen and zygapophyseal jointof C5 and C6 is large. transverse foramen from C4 to C6 are relatively farfrom zygapophyseal joint. Chapter two: The Biomechanical Study of the Effect of C4/5 and C5/6two Level Artificial Disc Replacement to Stress Distribution inZygapophyseal Joint of C5/6 and C6/7Objectives: To study the impact caused by two level ACD, ADR andACDF on cervical adjacent zygapophyseal joint stress distribution, thusto provide reference for clinical application of two level ADR.Methods: Eleven healthy adult fresh-frozen multi-segmentalcervical spine segments were utilized in this study and biomechanicallyevaluated under the following C4/5, C5/6 cervical disc conditions: (1)intactspine(intact group); (2)discectomy(ACD group); (3)the Bryan Discprosthesis implantation(ACDR group); (4)the intervertebral fusion(ACDFgroup). The testing was performed by using INSTRON computedmechanics test system (made in England). The load(25N～150N) of axial,flexion, extension, and lateral bending were applied on each group. Thestress changes of the caudad (C5/6, C6/7) zygapophyseal joint was tested bymodified cyclo-shaped miniature transducer. The data was analyzed bySPSS for windows 13.0, the statistic significance was set atα=0.05.Results: (1)Under axial, flexion, extension and lateral bendingloading, stress of the caudad (C5/6, C6/7) zygapophyseal joint increase asthe load increase. (2) Under axial, flexion, extension and lateral bendingloading, the stress of the caudad (C5/6, C6/7) zygapophyseal joint showedno difference between the intact group and ACDR group(P＞0.05). (3)Under axial, extension and lateral bending loading, two level disectomyindicated a significant increase in the stress of the caudad (C5/6, C6/7)zygapophyseal joint compared to intact group and ACDRgroup(P＜0.05), whereas under flexion loading there was a decrease ofStress (P＜0.05). (4) Under axial, flexion, extension and lateral bendingloading, the ACDF group resulted in significant increase of the stress ofthe caudad (C5/6, C6/7) zygapophyseal joint compared to intact group andACDR group(P＜0.05).Conclusions: 1.Two level artificial cervical disc replacement canmaintain stress in the caudad (C5/6, C6/7) zygapophyseal joint, thusreconstruct biomecanical property of cervical spine. 2. Two level cervicaldiscectomy can bring a certain degree of change in stress of the caudad (C5/6, C6/7) zygapophyseal joint. 3. Two level cervical discectorny andfusion can increase stress in the caudad (C5/6, C6/7) zygapophyseal joint,which may be one of the causes for adjacent cervical spondylosispostoperatively.Chapter there: The Clinical Observation of The ClinicalOutcomes After Two Level Artificial Disc Replacement andAnterior Cervical Discectomy and FusionObjectives:To observe the clinical outcome of the patients whoaccepted two level Bryan artificial disc replacement and patients withcervical discectomy and fusion, and analysis the effect on the caudadzygapophyseal joint.Methods: 35 patients with cervical C5/6 and C5/6 two level cervicaldisc degenerative spondylosis treated with two different operations werefollowed. They were divided into three groups according to the means ofoperation and time as followed: the group of artificial discreplacement(ACDR group), 5 cases were treated with two level artificialdisc replacement with a follow-up study of 12-22months; the group ofshort term of anterior cervical discectomy and fusion(ACDF group1), 15cases received operation with a follow-up study of 12-30 months; thegroup of medium and long term of anterior cervical discectomy andfusion(ACDF group2), 15 cases received operation with a follow-upstudy of 5-8 years. The score of JOA, the scale of Odom, the range ofmotion(ROM) shown by X-ray film of adjacent segment and the, degreeof degeneration revealed by X-ray and CT scan of adjacent caudadzygapophyseal joint in 6, 12 months and 2-year, 5-year were analyzedpre-operatively and post-operatively. The data was analyzed by SPSS forwindows 13.0, Paired-samples T Test was used to detect the differenceamong the different groups, the statistic significance was set atα=0.05.Results: (1) The score of JOA and the rank of Odom:There aresignificant difference between pre-operation and different period of post- operation(P＜0.05). There are no difference in score of JOA, rank ofOdom, between the group of artificial disc replacement and the ACDFgroup1 of intervertebral fusion in 6 months and 1 year follo-uppostoperatively (P＞0.05). the score of JOA and rank of Odom in theACDF group2 decreased in 5 years compaered with 1 and 2 yearpost-operatively (P＜0.05); (2) The range of motion of adjacent caudadsegment: There are not difference in between the group of artificial discreplacement and the ACDF group1 of intervertebral fusion in 6 monthsand 1 year follo-up postoperatively (P＞0.05); The range of motion ofadjacent caudad segment in the ACDF group2 increased in 5 yearscompaered with 1 and 2 year post-operatively (P＜0.05); (3) The degree ofdegeneration of adjacent caudad zygapophyseal joint: There are notdifference in between the group of artificial disc replacement and theACDF group1 of intervertebral fusion in 6 months and 1 year follow-uppostoperatively (P＞0.05); The degree of degeneration of adjacent caudadzygapophyseal joint in the ACDF group2 increased in 5 years compaeredwith 1 and 2 year post-operatively (P＜0.05).Conclusions: (1)The short term outcomes of two level artificial discreplacement or anterior cervial discectomy and fusion are satifactory, noobvious degenerative effects showed in adjacent caudad zygapophysealjoint. (2)The midium and long term outcomes of two level cervialdiscectomy and fusion decrease and degeneration occurs in adjacentcaudad zygapophyseal joint. (3)Further observation still needed to studythe medium and long term clinical outcomes of two level artificial discreplacement. |
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