| Objective To analyze the incidence and risk factors of proximal junctional kyphosis(PJK)following posterior long instrumented spinal fusion in Adult Degenerative Scoliosis patients.Methods From July 2011 to July 2016,in the spine surgery of the first Affiliated Hospital of Fujian Medical University,21 patients diagnosed with degenerative scoliosis treated with posterior long instrumented spinal fusion were retrospectively analyzed.The patients were included in group PJK at the last follow-up,the rest of the patients were included in the non PJK group.Comparing the differences of patient data,surgical data and radiographic parameters between the two groups which recorded before operation,3 months after operation and the last follow up time,investigating the incidence and risk factors of the PJK.The individual data included age,sex and body mass index(BMI).The surgical data included upper instrumented vertebra(UIV)level,lowest instrumented vertebra(LIV)level,the number of instrumented and fused vertebrae,interbody fusion.The radiographic parameters include the proximal junctional kyphosis angle(PJKA),the lumbar lordosis(LL),the thoracic kyphosis(TK),pelvic incidence(PI),pelvic tilt(PT),sacral slope(SS),global sagittal alignment(GSA),sagittal vertical axis(SVA).Results:All of the 21 ADS patients followed up 14.95±9.43 months(6-50 months),including 3 males and 18 females,aged(44-70)years,mean age(61.10 + 7.37)years,the mean number of instrumented levels was 7.38±1.56(5-11).PJK was developed in 4 of 21 patients(19.1%)until final follow-up,who were enrolled as the PJK group,and 17 patients without PJK at final follow-up were enrolled as the non PJK group.There was a statistically significant differences in PJKA between PJK group and non PJK group(17.93°±3.58°and 6.01°±2.39°,P<0.05).There was no statisticallysignificant difference between the two groups in individual data(age,sex,BMI)and surgical data(UIV and LIV position,fixed segment number,interbody fusion),P>0.05.There was a statistically significant difference between the two groups in preoperative TK,preoperative PI,postoperative PI-LL,preoperative and postoperative GSA,P < 0.05.There were statistically significant differences between the two groups in number of cases with preoperative TK > 30°,preoperative PI > 55°,preoperative and postoperative GSA > 45°,P < 0.05.Conclusion:the incidence of proximal junctional kyphosis(PJK)following posterior long instrumented spinal fusion in Adult Degenerative Scoliosis patients is 19.1%.The preoperative TK > 30°,preoperative PI > 55°,preoperative and postoperative GSA > 45°,preoperative PI-LL mismatch were risk factors of PJK.In order to reduce the incidence of PJK,the state of the sagittal plane should be fully evaluated before surgery,and the rational reconstruction of the balance of the pelvis sagittal surface should be paid attention during the operation. |
