Background:Recent studies have suggested an association between elevated pelvic incidence (PI) and the development of lumbar spondylolysis.However,there is still lack of investigation for Han Chinese people conceming the normal range of spinopelvic parameters and relationship between abnormal sagittal parameters and lumbar diseases.The objective of the study was to investigate sagittal lumbosacral parameters of adult lumbar spondylolysis patients in Han Chinese population.Methods:A total of 52 adult patients with symptomatic lumbar spondylolysis treated in the General Hospital of Armed Police Force (Beijing,China) were identified as the spondylolysis group.All the 52 patients were divided into two subgroups,Subgroup A:36 patients with simple lumbar spondylolysis,and Subgroup B:16 patients with lumbar spondylolysis accompanying with mild lumbar spondylolisthesis (slip percentage ＜30％).Altogether 207 healthy adults were chosen as the control group.All patients and the control group took lumbosacral lateral radiographs.Seven sagittal lumbosacral parameters,including PI,pelvic tilt (PT),sacral slope (SS),lumbar lordosis (LL),L5 incidence,L5 slope,and sacral table angle (STA),were measured in the lateral radiographs.All the parameters aforementioned were compared between the two subgroups and between the spondylolysis group and the control group with independent-sample t-test.Results:There were no statistically significant differences of all seven sagittal lumbosacral parameters between Subgroup A and Subgroup B.PI,PT,SS,and LL were higher (P ＜ 0.05) in the spondylolysis group than those in the control group,but STA was lower (P ＜ 0.001) in the spondylolysis group.Conclusions:Current study results suggest that increased PI and decreased STA may play important roles in the pathology of lumbar spondylolysis in Han Chinese population.