| Chapter 2:Skeletal growth velocity of adolescent idiopathic scoliosis:abnormal in spine but normal in lower limbsObjective:We compared the peak height velocity（PHV）time point of the lower limbs between adolescent idiopathic scoliosis（AIS）and healthy adolescents and analyzed whether abnormal growth of the lower limbs exists in patients with AIS.Methods:Female AIS patients with a thoracic Cobb angle of 20°to 60°were enrolled in the current study.The major Cobb angle,length of the spine（LOS）,length of the lower limbs（LLL）,and height of the pelvis（HOP）were measured.In addition,Ratio SLwas defined as LOS/LLL;Ratio SPwas defined as LOS/HOP;and Ratio PLwas defined as HOP/LLL.All patients and healthy controls were classified into three groups according to skeleton maturity status:pre-PHV,defined as Risser 0,and open triradiate cartilage（TC）;during-PHV（Risser 0,and closed TC）;and post-PHV（Risser ranging from 1 to 5）.Results:Ratio SLand Ratio SPwere significantly higher in scoliosis patients at Risser≥4compared to healthy controls（all,P<0.05）.However,Ratio PLwas similar between patients with AIS and healthy controls in both the Risser 0 and Risser≥4 groups.The change in ratio from pre-PHV to post-PHV showed similar trends between patients with AIS and healthy controls;both Ratio SLand Ratio PLwere significantly lower in the during-PHV group（all,P<0.05）.Conclusions:The final length of the lower extremities was similar between groups,while the peak growth of the lower extremities was earlier than that of pelvis and spine in both patients with AIS and healthy adolescents,indicating that lower limb growth pattern was not altered in AIS patients.Chapter 3: An analysis of the interactions between the spine,pelvis,and lower limbs in asymptomatic adults with limited pelvic compensationObjective: We conducted this retrospective study to evaluate the offsets of different centers of gravity in asymptomatic populations and to investigate how the global sagittal alignment is supported.Methods: The following parameters were measured: cervical lordosis,thoracic kyphosis（TK）,lumbar lordosis（LL）,pelvic incidence（PI）,pelvic tilt（PT）,the ratio between PT and PI（PT/PI）,sacral slope,PI minus LL（PI-LL）,the sagittal vertical axis（SVA）,cranial SVA to ankle center（Cr-A）,Cr SVA to the femoral head center（Cr-FH）,C2 SVA to the femoral head center（C2-FH）,pelvic translation（P.Shift）,and knee angle（KA）.Participants were divided into subgroups based on the PT/PI ratio.Mean values were compared using the t-test,and correlations were assessed using Pearson’s coefficient.Results: A total of 82 asymptomatic adults were enrolled.The average PT/PI in subgroup1 was the smallest,showing that individuals in this group may have limited pelvic retroversion.No significant differences in Cr-FH,Cr-A,or C2-FH were found between subgroups（all P>0.1）,implying that global alignment was well supported in each group.Specifically,C2-FH showed minor changes between subgroups（P=0.998）,showing that C2-FH may be a target for sagittal compensation.There were positive correlations between PT/PI and both P.Shift and SVA（r=0.930 and r=0.606,respectively）.However,Cr-FH,Cr-A,and C2-FH were not significantly correlated with P.Shift or PT/PI（all P>0.05）.Weak correlations existed between Cr-A,Cr-FH,and age（all P>0.2）.Conclusions: This study revealed that the Cr-FH and C2-FH offsets are stable across the population and could be maintained by regulating only the sagittal spinal curvature when pelvic compensation is limited.Cr-FH is not affected by age in the asymptomatic population.Chapter 4: The compensatory pattern of sagittal profile in patients with degenerative scoliosisObjective: To investigate the effects of lower limb compensation on full-body sagittal alignment,and to explore the whole body compensatory pattern in degenerative scoliosis（DS）,by comparing the parameters of patients with and without lower limb compensation on standing EOS full body films.Methods: Forty-three DS patients in our hospital were included.All patients underwent full body EOS films preoperatively.The following sagittal parameters were recorded:thoracic kyphosis,lumbar lordosis,pelvic incidence,sacral slope,pelvic tilt and sagittal vertical axis.The horizontal offset between anatomical landmarks on the sagittal plane was measured,including the CCOM to the ankle center（Cr-A）,the C2 to the ankle center（C2-A）,the C7 to the ankle center（C7-A）and the C2 to the femoral head center（C2-F）.The knee angle（KA）was also measured.All patients were divided into patients with lower limb compensation group and patients without lower limb compensation group according to whether KA was greater than 3 degrees.The differences of sagittal parameters between patients with and without compensation were compared by the independent sample t test.Results: A total of 20 DS patients without lower limb compensation and 23 DS patients with lower limb compensation were included in this study.There was no significant difference of PI or PI-LL between the two groups.The PT of patients with lower extremity compensation was 24.8°±10.4°,which was significantly greater than that of patients without lower limb compensation.The TK of patients with lower extremity compensation was 21.9°±14.0°,which was significantly higher than that of patients without lower extremity compensation.The KA of patients with lower extremity compensation was5.7°±1.0°,which was significantly higher than that of patients without lower extremity compensation.The SVA of patients with lower limb compensation was significantly smaller than that of patients without lower limb compensation.The difference of C2-A between the two groups was also statistically significant.The horizontal offset of patients with lower extremity compensation was significantly smaller than that of patients without lower extremity compensation.Conclusions: DS patients can make the sagittal profile of the whole body in a more favourable balance state through lower limb compensation,while patients without lower limb substitution may need to reduce the overall imbalance trend of thoracic kyphosis compensation sagittal plane due to pelvic posterior rotation limitation. |
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