The Clinical Significance Of The Imageological Score In Choosing Appropriate Operative Approach For Multilevel Cervical Spondylotic Myelopathy

Objective: Multilevel cervical spondylotic myelopathy (MCSM) is the pathological change of over two cervical segments,which is characterized by extensive compression of spinal cords and seriously damaged nerves.The major expression is pyramidal tract symptom.It often affects the routine work and the lives of the patients seriously.The rapid development of imageological technology,esp,the availability of MRI has played an important role in the diagnosis and cure of multilevel cervical spondylotic myelopathy,which has been treated widely with surgical operations,including anterior app- roach,posterior approach and anterior-posterior united approach. However,it is difficult to choose the appropriate approach despite the fact of widespread operative treatments.Reasonable choice of surgical method is the key to therapeutic efficacy.The imageology was always provided reliabilitical evidence for the diagnosis of cervical syndrome before.The aim of this research is to help surgeons to make appropriate choices between the three approaches based on imageological scores.Thereby,it will make the choices of operative approach for multilevel cervical spondylotic myelopathy to quantizing and to standardize. Method: 291 cases with MCSM were collected, including retrospective cases and prospective cases.226 patients with MCSM operated from January in 1998 to June in 2005 were retrospectively analyzed,81 cases treated with anterior approach, 92 with anterior-posterior united approach,53 with posterior approach.All of the retrospective patients were checked by X-ray,CT and MRI before operation.The retrospective imageo- logy of 226 cases were maded to unscrambling. Retrospective study analyzed 226 cases with 6 imageological indexes asso- ciated with the choice of appropriate MCSM operative appr- oach,which are:(1)the stability of cervical vertebra(which incl- udes the posterior process of cervical vertebra in the lateral projection,angular displacement of over 10 degrees,the horizon- tal displacement of over 3 mm in the bending projection);(2)the existence of local ossification(ossification≤2segments,including local OPLL,segmental OPLL,and local intervertebral disk hern- ia and calcification,osteophyma of posterior border of vertebral body…);(3)the degree of spinal cord compression;(4)the plum- pness of ligamenta flava(>5mm);(5)the existence of inborn cer- vical spinal stenosis(Pavlov<0.75);(6)the existence of continual ossification(ossification>2segments,including continual OPLL, segmental OPLL,intervertebral disk hernia and calcification, osteophyma of posterior border of vertebral body…).The max- imum likelihood method of discriminatory analysis was adopted to analyze the 6 imageological indexes and calculate corres- ponding imageological score.The imageological scores of ant- erior approach,anterior-posterior united approach and posterior approach for every case were calculated respecttively before operation,which were then compared and the one with the highest score was selected. Then,the operations of 65 cases were guided by the scores from August in 2005 to February in 2006,and studied by prospective analysis,21 cases treated with anterior approach,24 with anterior-posterior united approach,20 with posterior approach.All of the prospective patients were checked by X-ray,CT and MRI before operation.The maximum likelihood method was adopted to analyze the effect of discri- mination for the imageological scores and calculate the rate of coincidence.All the cases involving each approach were scored in terms of JOA standard(Japanese Orthopaedic Association), the JOA before and after operation of retrospective and pros- pective cases were compared.The RIS (rate of improved JOA score) were also compared.RIS=100%×(postoperative score- preoperative score)/(17preoperative score).To follow up all the postoperative cases,the patients were rechecked a week,4 weeks, and every three months after the operation,to record clinical symptoms,physical signs,neural function,conventional X-ray of orthophoria and lateral position,orthotopic-lateral X-ray for postoperative cervical vertebra(postoperative CT or MRI in some cases);to observe the position of internal fixation,bone graft fusion condition,the height of intervertebral space, physio- curvature maintenance;and to examine if there was pseudoarticulation formation,and if there was any sign of failure with of internal fixation device,such as loosening, movement or breakage.Result: The imageological score of three operative appro- aches were determined.The maximum likelihood method was adopted to analyze the effect of discrimination for the imageological scores.The coincidence rate of retrospective discrimination was 84.07%,in which 87.65% for anterior appr- oach,80.43% for anterior-posterior united approach,84.91% for posterior approach,respectively;the coincidence rate of prosp- ective discrimination was 80.00%,in which 80.95% for anterior approach,79.16% for anterior-posterior united approach;80.00% for posterior approach, respectively.T-test was used to compare pre- and post-operative JOA scores of each group.The statistical results were significant(P<0.001,α=0.05),but the improvement rate was 59.61±8.06% for the retrospective,60.26±6.40% for prospective cases.The improvement rates compared have not significant difference(p>0.05,α=0.05).Complications in retros- pective cases include 3 cases: wound infection(1case),cerebr- ospinal fluid leakage(1case),Swan-neck deformity(1case).Com- plications in retrospective cases include 3 cases:incision hem- atoma(1case),cerebrospinal fluid leakage(1case).In all cases, there were no complications either due to loosening,movement or breakage of steel plate or bolt,or internal fixation,and there were no other severe complications.Conclusion: Imageological diagnosis is able to direct the choice between anterior,anterior-posterior united and posterior surgical treatment in MCSM(3-4segments).Thereby,it will make the choices of operative approach for multilevel cervical spond- ylotic myelopathy to quantizing and to standardize.