ABSTRACT
Objective To evaluate the clinical outcomes of K-line(-) ossification of posterior longitudinal ligament (OPLL) between single open-door posterior decompression with instrumented in situ fusion(PDF) and laminoplasty (LMP).Methods From February 2008 to February 2015,38 cases including 30 males and 8 females underwent posterior decompression due to K-line(-) OPLL in our institution.The age ranged from 48 to 76 years,mean 56.3±9.7 years.The OPLL canal occupation ratio ranged from 38.6％ to 72.5％,mean 58.1％± 13.6％.According to surgical procedures,26 cases were in PDF group and 12 cases were in LMP group.The data collected from both groups included complications,C2-C7 Cobb angle and neurologic symptoms evaluated based on the Japanese Orthopedic Association (JOA) score and JOA score recovery rate,and were analyzed with statistics in and between groups.Results All the patients were completed follow up with a mean of 3.6±2.1 years (range,2.5 to 7.0 months).At the final follow-up,the postoperative JOA score was 11.8± 1.9 points on average,improved from preoperative 7.7± 1.6 points (t=3.757,P＜0.05),the mean JOA score recovery rate was 44.2±6.7％in PDF group;and the postoperative JOA score was 9.1 ±2.1 points,improved from preoperative 7.9± 1.5 points (t=1.327,P＜0.05),the mean JOA score recovery rate was 29.5±5.0％ in LMP group.No significant difference was found in preoperative JOA score between the two groups (t=0.365,P＞0.05),however,there were significant differences in the postoperative JOA score (t=3.941,P＜0.05) and JOA score recovery rate (t=6.741,P＜0.05) at the final follow-up.In PDF group,the C2-C7 Cobb angle was 4.1±2.0°,similar with preoperative 3.8±1.6° (t=0.587,P＞0.05).On the contrary,the C2-C7 Cobb angle was-2.1°±1.8°,lower than preoperative 3.9°±1.2° (t=6.824,P＜0.05) in LMP group.Ten cases occurred C5 palsy (PDF:7;LMP:3),and 3 cases occurred wound infection (PDF:2;LMP:1).The complication rate was 34.6％ and 33.3％ (x2=0.003,P＞0.05),respectively.Conclusion Compared with LMP,PDF without correcting cervical alignment for patients with K-line(-) OPLL showed better neurological recovery and clinical efficacy.