Comparison Of Changes Of Sagittal Position Parameters And Clinical Effect On The Two Kinds Of Surgical Approach For The Treatment Of Multilevel Cervical Ossification Of The Posterior Longitudinal Ligament

Objective: To compare the changes of sagittal position parameters and curative effect between posterior cervical expansive open-door laminoplasty(EOLP)and posterior cervical laminectomy and lateral mass screw fixation(LMSF)in the treatment of multilevel cervical ossification of the posterior longitudinal ligament(OPLL).Methods: A retrospective analysis of the basic data of 65 patients with multilevel cervical OPLL who were admitted to our hospital and received surgical treatment from February 2017 to November 2019.They were divided into two groups according to the surgical approach,Thirty patients underwent posterior cervical laminectomy and lateral mass screw fixation in group A,which consisted of 21 male and 9 female patients.Thirty-five patients received posterior expansive open-door laminoplasty in group B,which consisted of 25 male and 10 female patients.All patients received preoperative and postoperative cervical X-ray examination.Collected the clinical data of the two groups before surgery and at the last follow-up,including C2-7 Cobb angle,C2-7 sagittal vertical distance(C2-7SVA),T1 slope(T1S),thoracic inlet angle(TIA),neck tilt(NT),Operation time,intraoperative blood loss,Japanese Orthopaedic Association(JOA),Visual Analogue Score(VAS),JOA improvement rate and Axial Symptoms,and then performed statistics and analysis.Results:The operation time and intraoperative blood loss in group A were significantly higher than those in group B(P<0.05).There was no significant difference in postoperative hospital stay between the two groups(P>0.05).There was no significant difference in preoperative C2-7Cobb,C2-7SVA,T1 S,TIA,NT,JOA score and VAS score between the two groups(P>0.05).There was no statistically significant difference in T1 S,TIA,NT,JOA score and VAS score between the two groups at the last follow-up(P>0.05),but there were significant differences in C2-7Cobb and C2-7SVA(P< 0.05).Before and after operation,the comparison of JOA score and VAS score in group A was statistically significant(P<0.05),but there was no significant difference in C2-7Cobb and C2-7SVA(P>0.05).Comparison of C2-7Cobb,C2-7SVA,JOA score and VAS score before and after surgery in group B showed statistically significant differences(P<0.05).The improvement rate of JOA was(62.48±10.21)% for group A,and(60.99±9.83)% for group B.There was no significant difference in the improvement rate of JOA between the two groups(P>0.05).There was no statistical difference between the improvement rate of JOA score and the change of sagittal parameters.The incidence of postoperative axial symptoms was 16.7% in group A and 31.4% in group B,and the difference was statistically significant(P < 0.05).The correlation between postoperative axial symptom and changes in sagittal parameters was statistically different(P<0.05).Postoperative C2-7Cobb angle decreased,C2-7SVA increased,and the incidence of axial symptoms increased.Conclusion: For patients with multilevel cervical OPLL,no matter whether EOLP or LMSF is chosen,good neurological improvement can be achieved.LMSF is superior to EOLP in maintaining the postoperative sagittal balance of cervical spine,but it is inferior to EOLP in terms of operation time and intraoperative blood loss.There was no significant correlation between postoperative cervical sagittal parameter changes and the improvement of the patient’s JOA scores after two kinds of surgical approach.LMSF is a reliable method to maintain the cervical alignment,and it also has a preventive effect on the development of postoperative axial symptoms.The higher occurrence rate of axial symptoms after EOLP may be related to the significant decrease of C2-7Cobb and the significant increase of C2-7SVA.