| Objective:There is still no consensus on the optimal management approach in scoliosis with Chiari I malformation(CMI)and syringomyelia(SM)has been reached.Although surgeons experienced in treating idiopathic scoliosis(IS)have been attempts to one-stage direct spinal surgical correction without previous neurosurgical decompression to treat scoliosis with CMI and SM,there is still lack of evidence to demonstrate its long-term outcomes and potential influences to associated SM and the study is limited to directly compared of radiological features and surgical correction outcomes between patients with scoliosis with CMI and SM and those with IS.This study retrospectively analyzed the more than 5 years’ follow-up outcomes of scoliosis with CMI and SM treated by one-stage spinal correction to explore potential factors which could influence the prognosis of SM in these patients;in addition,this study directly compared of radiological features and surgical correction outcomes between patients with scoliosis with CMI and SM and those with IS.Methods:1.The follow-up outcomes of more than 5 years after one-stage posterior correction of scoliosis with Chiari I malformation and syringomyelia:a retrospective study was performed on 23 patients with CMI and SM associated scoliosis treated from January 2007 to June 2015.The patients had complete clinical data and were followed up for more than 5 years after one-stage spinal correction.There were 19 males and 4 females with an average age of 16.0±5.9(range,10-39)years old.The one-stage spinal correction was performed on all the patients,including 10 patients with posterior vertebral column resection(PVCR),13 patients with simple spinal correction without shortening osteotomy.The spinal radiographs were obtained from all patients preoperatively,postoperatively and at final follow-up.Syringomyelia size and change were measured based on the results of MRI.According to full-spine standing radiographs,the spine sagittal and coronal correction rate were evaluated.According to the results of MRI,the average cervical syrinx tension ratio(CSTR)was used as an indicator of syrinx size and change,and a≥20%decline was set as a boundary of syrinx improvement at the final follow-up.According to the degree of CSTR decline,all the cases were divided into two groups:with or without cervical SM improvement.And the cases were also divided into with or without PVCR based on whether the spinal shortening osteotomy was performed intraoperatively.Then gender,age at surgery,apical level,main scoliosis,kyphosis,deformity angular ratio(DAR),length of syrinx,average CSTR,preop traction,No.of fusion segments,coronal correction rate,sagittal correction rate,syrinx improvement,and period of the follow-up were compared separately.2.Comparison of radiological features and surgical correction outcomes between scoliosis with Chiari I malformation and syringomyelia and idiopathic scoliosis:twenty-two patients with scoliosis with CMI and SM were enrolled retrospectively and matched with 22 IS patients for sex,age,scoliosis classification,and Cobb angle.All patients underwent one-stage posterior spinal correction fusion surgery.Coronal and sagittal radiographic parameters were evaluated before surgery,postoperative,and at the final follow-up(at least 5 years).Results:1.The average follow-up period of all patients was 6.2±1.1 years(range,5-9 years).The average scoliosis angle reduced from 77.1°±28.0° before surgery to 27.80°±18.4° after surgery and 29.5°±21.2° at the final follow-up,with a correction rate of scoliosis of(65.7± 13.0)%.The average kyphosis angle reduced from 57.2°±31.9° to 29.3°±15.2° after surgery and 32.4°±16.5° at final follow-up,with a correction rate of kyphosis of(48.4±22.6)%.At final follow-up,the spinal correction and fusion were satisfied,and no patient experienced deterioration of neurological function.In all patients,the improvement rate of CSTR was 47.8%.There were 11 patients in the syrinx improvement group and 12 patients in the without syrinx improvement group.Of patients with syrinx improvement,the mean age at surgery was bigger(18.6±7.5 years vs.13.7±2.4 years,P=0.040),the frequency of undergoing PVCR was more(81.8%vs.16.7%,P=0.012),and the number of fusion segments was bigger(14.2±0.9 vs.12.3±2.9,P=0.044)than those in the group without syrinx improvement.However,there was no significant difference in gender,apical level,main scoliosis,kyphosis,DAR,length of syrinx,average CSTR,preop traction,coronal correction rate,sagittal correction rate,and the follow-up period(P>0.05).The patients who underwent PVCR had severer scoliosis(98.8°±13.8° vs.60.5°± 24.5°,P=0.000)and kyphosis(74.8°±37.5° vs 43.6°±18.6°,P=0.032),as well as greater coronal DAR(15.6°± 4.2°per level vs.10.2°±4.2°per level,P=0.006),sagittal DAR(12.0°±7.6° per level vs.6.7°±3.9° per level,P=0.040)and total DAR(26.8°±11.4° per level vs.15.3°±6.5° per level,P=0.006)than those without PVCR.There were more frequent uses of preoperative traction(70.0%vs.23.1%,P=0.024),longer fusion segments(14.2±1.2 levels vs.12.4±2.7 levels,P=0.045),and higher syrinx improvement rate(80.0%vs.23.1%,P=0.007)in the patients with PVCR.However,there was no significant difference in gender,age at surgery,apical level,length of syrinx,averaging CSTR,coronal correction rate,sagittal correction rate,and the follow-up period(P>0.05).2.The case matches were relatively ideal except one pair with the main curve in the opposite direction.There was no significant difference in sex,age,operation time,estimated blood loss,fusion length,screw density,final follow-up periods between the two groups(P>0.05).No significant differences were found between the two groups in the main curve parameters,main curve flexibility,apical level,main curve constitutes vertebral level,deformity angular ratio(DAR).There was no significant difference in coronal Cobb angle,sagittal kyphosis,thoracic kyphosis(TK),lumbar lordosis(LL),coronal balance,sagittal vertical alignment(SVA),correction rate,Correction loss rate before surgery,after the operation or at the final follow-up(P>0.05).Conclusion(s):1.One-stage spinal correction can be another good choice in selected patients without preoperative clinically detectable neurologic deficit of CMI and SM associated scoliosis,which not only achieves safe spinal correction without neurological intervention,but also steadily improves and stabilizes SM in most patients.2.Despite the differences in preoperative status,with demographic and scoliotic coronal parameters matched,scoliosis with CMI and SM and IS had comparable sagittal radiographic parameters and main curve flexibility,furthermore,pedicle-scre-based one-stage posterior spinal correction fusion achieved comparable surgical correction outcomes between the two groups. |
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