Changes of cervical sagittal alignment after posterior correction surgery in Lenke 5 adolescent idiopathic scoliosis

English Keywords:Adolescent idiopathic scoliosis  Lenke 5  Correction surgery  Cervical sagittal alignment

English Abstract:

  【Abstract】 Objectives: To analyze the changes of cervical sagittal alignment(CSA) in Lenke 5 adolescent idiopathic scoliosis(AIS) after posterior correction surgery. Methods: A total of 43 Lenke 5 adolescent AIS in Spine Department of PLA General Hospital from July 2011 to July 2017 was retrospectively analyzed. Cervical lordosis(CL), thoracic kyphosis(TK), thoracolumbar kyphosis(TLK), lumbar lordosis(LL), lordosis in fusion(LIF) and C7 sagittal vertical axis(SVA) were measured on lateral X-ray at preoperation, postoperation and last follow-up. The general data included gender, age, Risser score, the follow-up time, the number of vertebras in fusion segment(NVF) and TL/L curve(TL/L C). According to the cervical sagittal alignment at preoperation, patients were divided into the lordotic group(L group, pre- CL＜0°) and kyphotic group(K group, pre- CL≥0°). According to the change of cervical sagittal alignment at last follow-up vs preoperation, patients were divided into the lordosis increased group(I group) and the lordosis decreased group(D group). T-test was used to analyze the differences of parameters between L group and K group, I group and D group. LSD-t test was used to analyze the differences of parameters at preoperation, postoperation and last follow-up. Pearson correlation test was used to analyze the correlation between CL and corresponding parameters in I and D group. α=0.05 was difined in the two-sided test. Results: All the 43 patients, 10 males and 33 females, with age of 15.90±4.98 years and follow-up of 22.84±14.10 months, were divided into L group(n=15) & K group(n=17) preoperatively, and into I group(n=26) & D group(n=17) at last follow-up. No statistically significant difference of the general parameters was found between L group and K group, I group and D group. In all patients, the final TK increased when compared to preoperative TK(P=0.000); the postoperative TLK was significantly different from preoperative TLK(P=0.000), and no statistically significant difference was found among preoperative， postoperative and final CL. Subgroup comparisons between L group and K group showed significant differences(P<0.05) of preoperative CL(P=0.000), LIF(P=0.029) and SVA(P=0.003). Intra-group comparisons in group K showed increased CL(P=0.025) and TK(P=0.000) at last follow-up, and smaller postoperative TLK(P=0.002) which continued to last follow-up(P=0.002). Subgroup comparisons between group I and group D showed significant differences(P<0.05) of preoperative LL(P=0.043) and CL(P=0.000). Final CL significantly increased when compared to preoperative CL(P=0.008), and TK significantly increased compared to preoperative(P=0.000) and postoperative TK(P=0.001) in group I. TLK showed smaller at postoperation than at preoperation(P=0.005), which was kept at last follow-up(P=0.006) in I group. LL showed lager at postoperation than at preoperation(P=0.011), which was kept at last follow-up(P=0.001) in D group. There were correlations between CL and TK, CL and SVA preoperatively in group I. CL was also correlated with LL and SVA preoperatively, with TLK and SVA postperatively and with TLK at last follow-up in D group. Conclusions: Patients with kyphotic CSA preoperatively have their CL improved more significantly at last follow-up than that with lordotic CSA preoperatively. Increased TK during follow-up and appropriate TLK postperatively might result in improved CSA finally. Increased LL postperatively without the change of TK or TLK might not result in improved CSA finally.