| PART ?The correlation between implant density and clinical outcomes in patients with dystrophic scoliosis secondary to neurofibromatosis type I(NF1)Object:To investigate how implant density affects radiographic results and clinical outcomes in patients with dystrophic scoliosis secondary to neurofibromatosis type I(NF1).Methods:A total of 41 patients with dystrophic scoliosis secondary to NF-1 undergoing one stage posterior correction between June 2011 and December 2013 were included.Patients meeting the following criteria were selected for further analyses:(1)with a thoracic curve between 50 and 100 degrees;(2)treated with one-stage posterior spinal fusion and a minimum of 80%of the implants used were pedicle screws;(3)having a minimum two-year clinical and radiographic follow-up.Patients who had received prior surgery or 3-column osteotomy were excluded.General information of patients was recorded,as well as the preoperative and postoperative SRS-22 questionnaires.Pearson correlation analysis was used to analyze the association between implant density,coronal Cobb angle correction rate and correction loss at last follow-up,change of sagittal curve and apical vertebral translation(AVT).Patients were then divided into two groups:the low density(LD)group and high density(HD)group.Independent sample t tests were used to compare demographic data,radiographic and clinical outcomes before surgery and at last follow-up between the two groups.Results:Significant correlations were found between the implant density and the coronal correction rate of the main curve(r=0.505,p<0.01),coronal correction loss at final follow-up(r=-0.379,p=0.015).There was no significant correlation between implant density and change of sagittal profile(p=0.662)or AVT(p=0.062).The SRS-22 scores improved in the appearance domain,activity domain and the mental health domain within both groups,but there was no difference in any of the SRS-22 domains at final follow-up between the two groups(p>0.05 for all).Conclusions:The SRS-22 score was improved within both groups at final follow-up,no significant difference between HD and LD groups was found in any of the SRS-22 domains at last follow-up.However,the present study demonstrated that higher implant density was correlated with superior coronal correction and less postoperative correction loss in patients with dystrophic NF1-associated scoliosis.There seemed to be better radiographic outcomes with the higher implant density constructs in spite of higher hospital charges,but it still needs to be observed at a long-time follow-up.PART IIClinical application of three-dimentional O-arm navigation system in treating patients with dystrophic scoliosis secondary to neurofibromatosis type I Objective:To investigate the clinical outcomes and the accuracy of O-arm-navigation system assisted pedicle screw insertion in dystrophic scoliosis secondary to neurofibromatosis type I(NF-1).Methods:A retrospective study was conducted in 41 patients with dystrophic NF-1-associated thoracic scoliosis who were surgically treated at our spine center between June 2012 and October 2014 with more than 18 months follow-up.The patient were then divided into two groups:18 patients were under the assistance of O-arm-navigation-based pedicle screw insertion(O-arm group)and the remaining 23 patients'pedicle screws insertion were by free-hand(free-hand group).The X-ray and CT were analyzed to investigate the correction rate and safety of pedicle insertion.T-test was used to analyze measurement data and x2 test was used to analyze accuracy of screw insertion between the two groups.Results:The mean coronal Cobb angle was 63.2°±8.7° in the O-arm group and 66.9°±7.4° in the free-hand group(P>0.05),which was then corrected into 23.1°±6.8°and 30.2°±7.6°(t=2.231,P=0.031)after surgery respectively.The operation time was(265.0±70.3)min and estimated blood loss was(1 024±465)ml in the O-arm group.The operation time and estimated blood loss was(243.0±49.6)min and(1 228±521)ml respectively in the free-hand group,which had no significant difference between the two groups.However,the implant density was higher in the O-arm group than the free-hand group((64.1±10.8)%vs.(44.3±15.3)%)(t=4.652,P=0.000).The O-arm group comprised 122 screws,of which 72.9%was excellent,22.1%was good and 4.9%was bad.The free-hand group comprised 136 screws and 48.5%of them was excellent,33.8%was good and 17.6%was bad.The accuracy of pedicle screw insertion was higher in the O-arm group than the free-hand group(?2=10.140,P<0.05).By June 2016,the average follow-up period was(20.9±3.4)months(ranging from18 to 26 months),including(20.3±3.1)months in the O-arm group and(21.4 ± 5.5)months in the free-hand group.At last follow-up point,the coronal correction loss was significantly higher in the free-hand group than the O-arm group(6.3°±2.6° vs.4.4°±1.6°)(t=2.719,P=0.009).Conclusions:Compared with free-hand technique,O-arm-navigation technique could enhance the accuracy of pedicle insertion and the implant density of dystrophic region in dystrophic NF-1-associated scoliosis patients,which result in a better correction rate and less correction loss.Besides,the advantage of O-arm-navigation did not increase operative time and estimate blood loss. |
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