Comparison Between Stable Sagittal Vertebra and First Lordotic Vertebra Instrumentation for Prevention of Distal Junctional Kyphosis in Scheuermann Disease: Systematic Review and Meta-analysis.

Study Design: This study was a systematic review and meta-analysis. Objectives: To compare stable sagittal vertebra (SSV) and first lordotic vertebra (FLV) instrumentation for prevention of distal junctional kyphosis (DJK) in Scheuermann disease. Summary of Background Data: The SSV has been increasingly chosen as the lowest instrumented vertebra to prevent DJK, and some studies have provided supportive results. However, other studies demonstrate that lowest instrumented vertebra located in the FLV has similar DJK incidence with the benefit of saving levels. Materials and Methods: Electronic searches of PubMed, Embase, the Cochrane Database, and Web of Science were performed. Radiographic parameters, incidence of DJK, and revision surgery rates were compared between SSV and FLV groups. The odds ratio (OR) was used to identify differences between the groups and PResults: Four studies with a total of 173 patients were included. There were no differences between the SSV and FLV groups in most radiographic parameters. The incidence of DJK among 173 patients was 20.8% (36/173). The SSV group demonstrated a significantly lower DJK rate than the FLV group (OR, 0.11; 95% confidence interval, 0.04-0.30; PI2=39%). In this study, 5.9% (5/85) of the SSV group and 43.6% (24/55) of the FLV group developed DJK; 27.8% (10/36) who developed DJK underwent revision surgery, including 25.0% (6/24) in the FLV group and 40.0% (2/5) in the SSV group. The revision surgery rate was lower in the FLV group than in the SSV group, with no statistical difference (OR, 3.27; 95% confidence interval, 0.26-41.73; P=0.36; I-2=0%). Conclusions: The overall DJK rate in Scheuermann disease was 20.8%, and 27.8% of DJK patients needed revision surgery. A distal fusion level including the SSV demonstrated a significantly lower DJK rate.