Clinical Research On Scoliosis Associated With Syringomyelia

Clinically,neuromuscular scoliosis is not rare.The syringomyelia can be found in a considerable number of patients with scoliosis based on magnetic resonance imaging(MRI)examination.Chiari I malformation(CIM)and idiopathic syringomyelia(ISm)are more common in patients with scoliosis and syringomyelia.However,there are no relevant literatures on the differences in clinical and radiographic characteristics,and the clinical outcomes of one-stage posterior correction on scoliosis between the two conditions.This study intends to conduct a series of researches to explore the clinical manifestation,radiographic feature,and the clinical outcome of one-stage posterior correction on spine deformity in scoliosis patients associated with syringomyelia,who are represented by patients with CIM or ISm.The contents of this study include the following three parts:Part I.Clinical Manifestations and Radiological Characteristics in Patients with Idiopathic Syringomyelia and Scoliosis;Part ?.Comparison of Radiological Features and Clinical Characteristics in Scoliosis Patients with Chiari I Malformation and Idiopathic Syringomyelia;Part ?.Surgical Scoliosis Correction in Chiari I Malformation with Syringomyelia Versus Idiopathic Syringomyelia:A Matched Study.Part ?.Clinical Manifestations and Radiological Characteristics in Patients with Idiopathic Syringomyelia and ScoliosisObjective:The correlation among the scoliosis,syrinx and neurological deficit is still unclear in the scoliosis patients associated with idiopathic syringomyelia(ISm).Previous study thought that the deviation of syrinx might participate in the development of scoliosis or neurological deficit in scoliosis patients with syringomyelia.Therefore,this study aimed to clarify the clinical manifestations and radiological characteristics of scoliosis patients associated with ISm,and to investigate the relationship between scoliotic curve,syrinx and neurological deficit in scoliosis patients associated with ISm.Methods:Fifty-five patients with scoliosis and ISm were identified and reviewed retrospectively from our spine center.Radiographic features of syrinx,scoliosis and clinical manifestations of neurological deficits were collected.The maximum syrinx/cord(S/C)width ratio was defined as the largest anteroposterior diameter of syrinx divided by the diameter of spinal cord at the same level.Patients were classified into two groups,the thoracic group(T group,apex vertebra located from T2 to intervertebral disk of T11-T12)and the thoracolumbar/lumbar group(TL/L group,apex vertebra located from T12 to L5).Results:Among total fifty-five patients with scoliosis and ISm,there was no correlation between the radiological features of idiopathic syrinx and scoliotic curve parameters.The TL/L group had a lower level of most caudal extent(13.7± 4.6 vs.10.6±4.6,p=0.029)and lower level of maximum S/C width ratio(12.0±4.6 vs.8.7±4.1,p=0.016)than that in T group.The deviated side of syrinx was not coincident with major curve convexity(27.2%concordance rate,p=0.522)or dominant side of neurological deficit(16.3%concordance rate,p=0.212).Conclusions:In scoliosis patients with ISm,the distribution of syrinx tended to extend caudally in the spinal cord as the location of the major curve of scoliosis moved downward,suggesting a relationship between the distribution of syrinx and the location of the major curve of scoliosis.However,the deviated syrinx may not be the primary cause of scoliosis in patients with ISm.Part ?.Comparison of Radiological Features and Clinical Characteristics in Scoliosis Patients with Chiari I Malformation and Idiopathic SyringomyeliaObjective:Chiari I malformation(CIM)and idiopathic syringomyelia(ISm)are two common types in scoliosis patients associated with syringomyelia.However,the differences in syrinx characteristics,scoliotic parameters,and neurological deficits between scoliosis patients with CIM and scoliosis patients with ISm are still unclear.In previous studies,routine two-dimensional(2D)measures of syrinx in magnetic resonance imaging(MRI),such as the length and width,cannot objectively describe the three-dimensional(3D)characteristics and reveal the relationship between syrinx and spinal deformity in scoliosis patients associated with syringomyelia.This study aimed to compare syrinx characteristics,scoliotic parameters,and neurological deficits between CIM and ISm in the scoliotic population,and to evaluate the correlation between the 2D/3D features of syrinxes and the severity of spinal deformity and neurological deficits.Methods:Retrospective analysis was performed on two hundred and forty-five scoliosis patients associated with syringomyelia treated in our spine center.After screening based on the inclusion/exclusion criteria,clinical and imaging data of sixty-four patients with scoliosis combined with CIM and seventy-eight patients with scoliosis combined with ISm were systematically collected.And the differences in scoliosis,syrinx,and neurological signs/symptoms between these two groups were compared.From total one hundred and forty-two patients,thirty-six scoliosis patients with CIM and thirty-six scoliosis patients with ISm were selected.Patients in the two groups were matched based on gender,age,scoliosis curve and Cobb angle of the major curve,and the differences in clinical and radiological parameters between these two groups were further compared under the condition of similar demographic characteristic and coronal features of scoliosis.The 3D reconstruction of syrinx was conducted in sixty-nine scoliosis patients associated with syringomyelia based on the digital imaging and communications in medicine(DICOM)format files of spinal MRI by using Mimics 17.0 software.The 2D/3D syrinx features,including length,width,cross-sectional area,and volume,were measured.And the correlation among the syrinx size,scoliosis coronal/sagittal parameters and the neurological deficits were analyzed.Results:Among the sixty-four scoliosis patients with CIM and seventy-eight scoliosis patients with ISm,the CIM group had a longer syrinx(12.0±4.4 vs.8.6±4.6 vertebral levels,p<0.001),a larger maximum syrinx/cord(S/C)width ratio(62.6%±18.6%vs.52.1%±19.3%,p=0.002),a higher cranial extent(3.8±2.2 vs.5.6±3.2,p<0.001),and a lower caudal extent(14.9±3.4 vs.13.2±4.2,p=0.017).There were no significant differences in coronal/sagittal parameters of scoliosis and neurological symptoms/signs between the two groups.Compared with thirty-six ISm patients matched by gender,age,and scoliosis coronal parameters,the CIM group had a longer syrinx(12.9±4.0 vs.8.7±5.5 vertebral levels,p<0.001),a higher cranial extent(3.6±2.2 vs.5.2±3.5,p=0.027),and a lower caudal extent(15.6±2.9 vs.13.0±4.6,p=0.006).No differences in neurological deficits were identified between the CIM and ISm patients.In the sixty-nine scoliosis patients with syringomyelia who had 3D reconstruction of syringomyelia,the maximum S/C width ratio(c=0.315,p=0.008)and the S/C volume ratio(c=0.265,p=0.028)significantly correlated with coronal balance.In the CIM group,syrinxes were longer(12.0±4.3 vs.8.9±4.2 vertebral levels,p=0.003),and had larger maximum S/C width ratio(62.0%%±18.3%vs.51.8%±18.1%,p=0.023)and larger cross-sectional area ratio(38.0%±23.0%vs.27.3%±17.9%,p=0.034)than the ISm group.The 2D/3D features of syrinxes did not statistically correlate with other parameters of scoliosis,or the neurological deficits.Conclusions:Compared with scoliosis patients with ISm,scoliosis patients with CIM had longer and larger syrinxes.Differences in syrinx parameters between these two groups suggest different mechanisms of syringomyelia,which may be related to the obstruction at the foramen magnum level caused by Chiari malformation.The size of syrinx is related to the coronal balance of the spine,to some extent,supporting the theory that syringomyelia may be involved in the development of scoliosis by causing the imbalance of the paravertebral muscles.However,the size of the syrinx may not affect the severity of spinal deformity or the neurological deficits.Part III.Surgical Scoliosis Correction in Chiari I Malformation with Syringomyelia Versus Idiopathic Syringomyelia:A Matched StudyObjective:Previous studies have focused on the differences in clinical outcomes between patients with scoliosis associated with syringomyelia and patients with adolescent idiopathic scoliosis(AIS)following surgical correction of scoliosis.However,Chiari I malformation(CIM)and idiopathic syringomyelia(ISm),as two common types of scoliosis associated with syringomyelia,have not been reported on the clinical outcomes of scoliosis correction.Therefore,the aim of this present study was to compare radiographic features,clinical outcomes,and surgical complications after one-stage posterior correction on scoliosis between scoliosis patients with CIM and scoliosis patients with ISm.Methods:One hundred and twenty patients with scoliosis associated with syringomyelia were retrospectively analyzed.Twenty-one patients with scoliosis secondary to CIM were enrolled and matched by sex,age,and the Cobb angle of the scoliotic curve with twenty-one patients with scoliosis secondary to ISm.All patients underwent one-stage posterior scoliosis correction surgery,and they were evaluated by neurosurgeons before surgery without immediate neurosurgical intervention.Coronal and sagittal radiographic parameters were evaluated before surgery,immediately after surgery,and at the final follow-up(at least 2 years).We also collected data regarding syringeal features,neurological deficits,intraoperative neurophysiological monitoring(IOM),complications,and Scoliosis Research Society-22 questionnaire(SRS-22)scores.Results:Preoperatively,sex,age,coronal/sagittal scoliosis parameters,and neurological deficits were similar between the matched CIM and ISm groups.On average,the CIM group had a longer syrinx(12.3±3.6 vs.8.9±4.5 vertebral levels,p=0.010)than the ISm group.After the operation and at the last follow-up,the CIM and ISm groups showed similar correction rates for primary curves(70.9%±10.6%vs.69.5%±16.3%,p=0.739).There were no significant differences in coronal/sagittal parameters,IOM abnormalities,surgical complications,or SRS-22 questionnaire scores between the two groups.Conclusions:Despite scoliosis patients with CIM had longer syrinxes compared with scoliosis patients with ISm,one-stage posterior correction on scoliosis achieved comparable clinical and radiographic outcomes for both CIM-and ISm-associated scoliosis without neurological complications.These results suggested that the length of syrinx may not determine the risk of spinal cord injury in scoliosis associated with syringomyelia patients undergoing the scoliosis corrective surgery.For scoliosis associated with syringomyelia patients with normal neurological status or only mild neurological symptoms/signs,one-stage posterior corrective surgery for scoliosis may be safe without prophylactic neurosurgical intervention.