Objective To assess the application value of disposable syringe of low resistance (SLR) in epidural puncture.Methods One hundred and thirty-two patients scheduled to undergoing selective operation under epidural or combined epidural-spinal anesthesia were divided into glass syringe (GS) group and SLR group with 66 cases each by random digits table method.GS was applied in local anesthesia and epidural puncture with loss of resistance in GS group.While SLR was used in SLR group.The defect of the syringes' appearance was evaluated.The fastness between each sub-unit during the procedure was observed.The rupture,dropping,leakage,air leakage and blockage were also estimated.The heart rate,blood pressure,oxygen saturation and other adverse events were also observed.Results In SLR group,syringe excepted 1 case of slight resistance but did not affect the use,the rest of the components connected firmly,surface without defects,clear scale uniform color,not observed rupture,air leakage,leakage and blockage phenomenon,pump liquid and air resistance was small.In GS group,syringe surface without defects,clear scale uniform color,3 cases had loose connection,1 case with rupture when using,5 cases with air leakage and leakage,3 cases of pumping liquid or dry air resistance to 0.9％ sodium chloride and moist after use.There was significant difference in appearance and usage between two groups (x2 =10.324 5,P =0.001 3).There was no significant difference in a puncture success,first three puncture success and inject air negative pressure sensitivity between two groups (P ＞ 0.05).Conclusion SLR is worth to be applied in epidural puncture.

Objective To investigate the radiographic characteristics of posterosuperior fracture fragment of the injured vertebral body and its effects on the results of surgical treatment in thoracolumbar burst fractures.Methods A total of 45 patients with acute thoracolumbar burst treated by either anterior or posterior surgery from January 2014 to December 2015 were analyzed by retrospective casecontrol study.There were 24 males and 21 females with a mean age of 33.6 years (range,23-52 years).Fractured segments included T12 in six cases,L1 in 15,L2 in 14,L3 in 5,and L4 in 5.Based on AO classification,there were ten cases of A3 fractures and 35 cases of Ag fractures,among which four cases of A4 were combined with B2 injuries.Eleven patients underwent anterior surgery and 34 patients posterior surgery.The operation time and intraoperative blood loss were recorded.The following parameters were also measured pre-and post-operatively,namely the displacement and inversion angle of posterosuperior fracture fragment,Cobb angle,anteroposterior diameter (APD) of spinal canal,and American spinal injury association (ASIA) neurological scale.Results All patients were followed up for 11-24 months (mean,17 months).There were no complications except for one case of implant loosening at three months after anterior surgery.The average operation time was 138.3 minutes and intraoperative blood loss was 293.7 ml in anterior surgery while the average operation time was 77.5 minutes and intraoperative blood loss was 54.7 ml in posterior surgery (P ＜ 0.05).Compared with postoperative situation,the canal APD was increased by 55.5％ in anterior surgery and the corresponding increase was 14.9％ in posterior surgery (P ＜ 0.01).There was no significant difference between two groups in Cobb angle correction.Compared with situation before surgery,the postoperative ASIA grading was improved in 73％ of the patients in anterior surgery and while it was enhanced in 24％ of the patients in posterior surgery (P ＜ 0.05).On the aspect of spinal canal decompression,anterior surgery had obvious decompression effects.The canal APD of anterior surgery was 94.4％,which was larger than 88.5％ in posterior surgery,although the difference was not significant.Notably,when the fragment displacement was ≤ 8 mm,posterior surgery could achieve 97.4％ APD which was comparable with that of anterior surgery.In contrast,when the fragment displacement was ＞ 8 mm,the APD was much smaller in posterior surgery with only 78.5％ (P ＜ 0.05).Similarly,when the fragment inversion was ≤25° or ＞ 25°,the APD was significantly different in anterior surgery and posterior surgery (95.4％ vs.80.8％) (P ＜ 0.05).Conclusions Although posterior surgery for thoracolumbar burst fractures is easy to perform and has short operation time and little intraoperative blood loss,it cannot always guarantee adequate decompression of spinal canal.When the posterosuperior fragment displacement is ＞ 8 mm or when its inversion is ＞ 25°,stand-alone posterior indirect reduction technique is likely to lead to inadequacy of canal restoration.In this case,anterior surgery should be considered in order to achieve more complete canal decompression.Therefore,this radiographic characteristic of the posterosuperior fragment could serve as an approach reference for thoracolumbar burst fractures.