Study Of Relationship Between Morphology Of The Syringomyelia And Abnormal Somatosensory Evoked Potentials In Syringomyelia With Scoliosis

Part I Relationship between morphology of thesyringomyelia and abnormal somatosensory evokedpotentials in patients with syringomyelia and scoliosisObjectives To investigate the relationship between morphology of thesyringomyelia and abnormal somatosensory evoked potentials (SEP) in patients withsyringomyelia and scoliosis, and to explore its clinical significance.Methods36scoliosis patients with syringomyelia were enrolled in this study, andposterior tibial nerve SEP were performed. The SEP obtained from45age-matchedhealthy control individual were considered as the standard values. The following werenoted from the T1-weighted mid-sagittal MRI scan: configuration è length of syrinx èthe maximal ratio of syrinx to cord (S/C ratio).Absence of SEP waveforms,prolongation of peek latency or asymmetrical peek latency were defined aspathological change. The incidence of pathological SEP was determined in all patients. The correlation among them were investigated.Results The incidence of abnormal SEP in36scoliosis patients with syringomyeliawas38.88%(14/36).Both the Cobb angle and syrinx patterns (length è S C ratio) hadno correlation with SEP changesConclusion Abnormal conditions of somatosensory pathway does exist in asubgroup of scoliosis patients with syringomyelia. However, Cobb angle and syrinxpatterns (length,S C ratio) may not seem to play a role in the advance of abnormalSEP changes. Part II The bleeding pattern in ankylosing spondylitispatients with thoracolumbar kyphosis treated with pediclesubtraction osteotomyObjective: To investigate the bleeding pattern in ankylosing spondylitis (AS) patientswith thoracolumbar kyphosis undergoing pedicle subtraction osteotomy (PSO).Methods: Twenty-one AS patients performed with one-level PSO were included inthis study. There were19males and2females, with the mean age of35.7±12.7years (range,18to65years).The following parameters were recorded, includingglobal kyphosis (GK), the number of fixation segments and PSO level. The surgicalprocedures were divided into the following six phases exposure, pedicle screwsplacement, PSO, closure of the osteotomy site, correction rod placement and closureof the incision. The operation time and the blood loss in each stage were recorded.Results: The total blood loss was1893.8±378.5ml.The blood loss in the phases ofexposure, pedicle screws placement, PSO, closure of the osteotomy site, correctionrod placement and closure of the incision were116.6±52.5ml,236.4±91.1ml,832.1±223.5ml,210.9±61.8ml,244.7±42.0ml and228.5±46.1ml, respectively. Thepercentage of each stage was6.16%,12.48%,43.93%,11.13%,12.92%and13.38%,respectively.Conclusion: The largest amount of blood loss in the PSO phase was significantlymore than the others. Therefore, enough blood perfusion must be guaranteed toreduce the risk of spinal cord ischemia in this phase. Part III The bleeding pattern in adolescent idiopathicscoliosis patients treated with posterior pedicle screwinstrumentationObjective To demonstrate the bleeding pattern in the adolescent idiopathic scoliosis(AIS) patients underwent posterior pedicle screw fixation.Methods: Ninety-nine AIS patients undergoing posterior pedicle screw fixation wereincluded in this study. There were16males and83females, with the mean age of15.2±1.9years range,12to18years.The following parameters were recorded:global Cobb angle, fixation segments and the amount of pedicle screws. The surgicalprocedures were divided into four phases: exposure, pedicle screws placement,correction rod placement and closure. The time and the blood loss amount in eachstage were recorded.Results: The average operative time was172.7±24.9min. The total peri-operativeblood loss was897.6±414.2ml. Blood loss at the stages of exposure, pedicle screwsplacement, correction rod placement and closure were165.0±103.9ml è328.2±161.8ml è218.9±125.5ml and185.0±89.9ml, respectively. The percentage of bloodloss at each stage was18.4%36.6%24.3%and20.7%, respectively. The result ofPearson correlation analysis showed that Cobb angle, the amount of pedicle screws,fixation segments and the time of surgery were associated with total peri-operativeblood loss.Conclusion: The major blood loss stage was the pedicle screws placement andcorrection rod placement. The pre-operative Cobb angle, the amount of pediclescrews, fixation segments and the time of surgery were correlated to the patients’blood loss.