Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis Following Segmental Posterior Spinal Instrumentation and Fusion; Minimum 2 Years Follow-Up

Abstract

Background:To evaluate proximal junctional segment changes in Adolescent Idiopathic Scoliosis(AIS) the posterior spinal fusion and also instrumentation also and finding of probable risk factors, were all considered in this study.Methods: We retrospectively reviewed radiographs of 121 consecutive patients who underwent posterior spinal fusion for AIS from T3 or below, with a mean follow-   up of 32.8 months(range,24-83). All coronal and sagittal measurements including the proximal junctional kyphosis (PJK)angle recorded on standing anteroposterior and lateral radiographs preoperative, early postoperative and on follow-up radiographs.The data were analyzed using the Spss 10.0 software.Dependent(paired) samples student t-test was used for analysis between the groups Results: There was PJK angle above normal for the same junctional segment preoperatively in 13 patients (10.7%) and the incidence of the PJK postoperatively was   7.4% (9 patients, 7 female and 2 male), all detected until 2 years postoperation.The mean increase in the PJK angle from pre-operation until 6 weeks postoperation was 5.9° (range,0-13°)(P=0.02) and until 2 years post operation was 14.3° (range, 2- 16°)(p=0.000).The mean proximal junctional angle increased 1.6° until 2 years postoperation in non-PJK group(n=112).Conclusion: The prevalence of Proximal Junctional Kyphosis was low and a silent radiographic problem. In some cases is preventable with perfect pre-operative planning. There is no specific demographic or radiographic variables or instrumentation types associated with developing PJK