The progression of ossification of the posterior longitudinal ligament of the cervical spine: A follow-up study by CT imaging after laminoplasty / 中华骨科杂志

ABSTRACT

Objective To evaluate the CT imaging after laminoplasty for the patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.Methods From June 2011 to June 2016,Retrospectively analyzed the data of OPLL patients who underwent posterior cervical open-door laminoplasty.There were 21 patients finally enrolled in this study,which consisted of 11 male and 10 female aging from 55-69,mean(61.48±4.29).The preoperative patients all had severe symptoms of spinal compression.Collected the Japanese Orthopaedic Association Scores(JOA) Scores of all patients for gender,age,preoperative and postoperative follow-up.The length,width and thickness of OPLL were measured by CT scan and two-dimensional reconstruction of cervical spine during preoperative and follow-up,and the average progress rate was calculated.The relationship between OPLL size before surgery and OPLL progress rate after surgery was analyzed.Results A total of 21 patients were included in this study,with an average age of 61.48±4.29 years-old.The mean follow-up time was 3.36± 1.92 years.The JOA score of cervical spine was 11.81 ± 1.75 before operationand 14.43± 1.69 at the last follow-up time (t=3.8,P＜0.01).The progression rate of OPLL length,width and thickness was 3.54± 2.89 mm/year,0.49± 0.52 mm/year and 0.34± 0.21 mm/year,respectively.Compared with the width and thickness,the average progress speed of the length was statistically significant (t=3.6,P=0.003;t=3.8,P=0.002).The progression rate of the rostraland caudal of OPLL was 1.54 ±1.19 mm/year and 1.60±1.33 mm/year (t=0.1,P=0.559).Linear regression showed that OPLL length progression speed (mm) =0.05×preoperative length + 1.23,R2=0.26 and P=0.02.Theprogression rate of width and thickness of OPLL had no correlation with preoperative OPLL width and thickness.The progression rates of local,segmental,continuous,and mixed OPLL were 3.02±0.26 mm,2.97±0.65 mm,3.65± 1.14 mm,and 3.82± 1.27 mm per year.Conclusion The JOA score of the posterior open-door laminoplasty of the cervical OPLL patients was significantly improved during a short-term follow up.CT imaging follow-up showed there was progression of OPLL in length,width and thickness,and the progression rate of length was faster than width and thickness.However,there was no significant difference between the progression of rostral and caudal of OPLL.In addition,short-term follow-up showed a positive correlation between the progression rate of OPLL length and the length of OPLL preoperation.The progress rate of mixed and continuous OPLL may be greater than that of segmental and limited OPLL.