Objective To investigate the effectiveness of the micro-dynamic pedicle screw for the prevention of loosening between the screw and bone surface in lumbar spinal fusion.For this evaluation,the peek pull-out force(PPF)...Objective To investigate the effectiveness of the micro-dynamic pedicle screw for the prevention of loosening between the screw and bone surface in lumbar spinal fusion.For this evaluation,the peek pull-out force(PPF)after fatigue resistance testing at different cycles and semidiameter of screw insertion area of micro-CT image was compared between the micro-dynamic and traditional pedicle screws.Methods Forty lumbar vertebrae received a traditional pedicle screw on one side and a micro-dynamic pedicle screw on the other side as follows:15 vertebrae underwent instant pull-out testing(group A,traditional vs.group B,micro-dynamic);15 vertebrae underwent pull-out test after 5000-cyclic fatigue loading(group C,traditional vs.group D,micro-dynamic);and 10 vertebrae underwent pull-out test after 10000-cyclic fatigue loading(group E,traditional vs.group F,micro-dynamic).All vertebrae that after fatigue loading were scanned by using micro-ct to check the semidiameter of screw insertion area.The PPF,normalized PPF(PPFn),bone mineral density(BMD)and diameter of screw insertion area were compared between all groups.Results The BMD showed a weak significant correlation with PPF(r=0.252,P=0.024).The PPF in groups A and B(P=0.485),and groups C and D(P=0.184)did not show significant difference.However,the PPF in group F was significantly greater than that measured in group E(P=0.005).The PPFn of groups A,C,and E significantly decreased as the number of cycles increased(P=0.015).Meanwhile,the PPFn of groups B,D,and F remained consistent regardless of the number of cycles(P=0.367). The semidiameter of traditional pedicle screw insertion area was significantly larger than that of micro-dynamic pedicle screw insertion area(P<0.001).Conclusions This study compared the performance of a micro-dynamic pedicle screw versus that of a traditional pedicle screw using pull-out testing and micro-CT.The results showed that the micro-dynamic pedicle screw provides similar resistance in lowcycle fatigue testing and favorable resistance in high-cycle fatigue testing versus the traditional pedicle screw.The micro-dynamic pedicle screw provides stronger fixation stability versus the traditional pedicle screw,especially in high-cyclic fatigue loading condition versus the traditional pedicle screws.展开更多
Objective: It is important and helpful for surgeons to understand the correlation between spinal anatomy and screw trajectory before surgery. We aimed to assess a simple technique using 3D imaging software available o...Objective: It is important and helpful for surgeons to understand the correlation between spinal anatomy and screw trajectory before surgery. We aimed to assess a simple technique using 3D imaging software available on the hospital intranet for visual and quantitative feedback to prepare surgeons for an appropriate entry point and safe trajectory when placing cervical screws. Methods: A total of 59 cervical screws were inserted from C1 to T1 in 12 consecutive patients using this technique. First, a single CT optimal slice was selected from 3D CT images of the cervical spine to determine the intervals of bilateral entry points and lateral angle. Next, this 3D image was rotated to the lateral angle. Finally, bone was cut out on the entry point using subtractive manipulation, which removed the core of the pedicle or lateral mass. Screw trajectory was indicated, and surgeons could assess the correlation between surface landmarks, spinal anatomy, and screw trajectory. Posterior cervical fusion was performed using fluoroscopy. Postoperative outcomes and incidence of complications were retrospectively assessed. Results: One perforation (1.4%) was identified on postoperative CT images. No vascular injuries occurred. Differences in the intended entry point location and lateral angle of the screw from actual postoperative values were 1.49 ± 1.23 mm and 5.46。 ± 4.46。, respectively. Conclusions: A novel 3D CT imaging assessment underwent in cervical screw fixation. This technique is easily accessible on the hospital intranet and provides training in cervical screw placement for fellows. Surgeons can simulate screw placement and share surgical strategy.展开更多
Objective To explore the differences between anatomic and CT measurements for anterior transoral axial pedicle screw placement. Methods C2 vertebrae of 60 adult spines were measured anatomically,while 20 adult spine v...Objective To explore the differences between anatomic and CT measurements for anterior transoral axial pedicle screw placement. Methods C2 vertebrae of 60 adult spines were measured anatomically,while 20 adult spine vertebrae were展开更多
To explore the value of helical CT volume rendering technique (VRT) in post-operative evaluation of screw fixation of axis fractures.Methods There were 21 cases of screw fixation of axis fractures between February 200...To explore the value of helical CT volume rendering technique (VRT) in post-operative evaluation of screw fixation of axis fractures.Methods There were 21 cases of screw fixation of axis fractures between February 2002 and May 2004 in the study including six cases with fractures on axis body,five on odontoid process and 10 on axis body and odontoid process.All cases received X-ray plain film,helical CT scanning,multi-planar reformatting(MPR) and VRT.Results Screw fixation through axis body and massa lateralis atlantis was performed in 10 cases and that through axis body and odontoid process in 11.VRT could clearly display full aperture of screw orbit,location of screw and angle of fixation and hence was superior to X-ray plain film and MPR.Multi-angle VRT displayed asymmetrical space of odontoid process and massa lateralis atlantis in four cases and medial deviation of 2～5 mm of half screw in screw fixation through axis body and massa lateralis atlantis in six.Conclusion VRT can eliminate false shadow of fixation screw,clearly display full aperture of screw orbit and hence supply improtant imaging evidence for post-operative evaluation of screw fixation of axis fractures.7 refs,1 fig,1 tab.展开更多
目的:探讨椎体CT值与腰椎短节段内固定术后螺钉松动的关系,选取用于预测螺钉松动的CT临界值。方法:回顾性分析2006年7月~2015年6月在我院行腰椎短节段(≤2个椎间隙)内固定术且术前1个月内行腰椎三维重建CT检查,随访≥24个月的患者资料。...目的:探讨椎体CT值与腰椎短节段内固定术后螺钉松动的关系,选取用于预测螺钉松动的CT临界值。方法:回顾性分析2006年7月~2015年6月在我院行腰椎短节段(≤2个椎间隙)内固定术且术前1个月内行腰椎三维重建CT检查,随访≥24个月的患者资料。共297例,男104例,女193例,年龄54.3±12.5岁(21~80岁),随访36.1±16.5个月(24~110个月)。以末次随访X线评估螺钉松动和融合情况,根据螺钉是否松动及螺钉松动的位置,分为上端椎螺钉松动组、上端椎螺钉对照组和下端椎螺钉松动组、下端椎螺钉对照组,另将下端椎螺钉按是否固定到S1分为两个亚组,并分别分析各亚组内松动组和非松动组的差异。测量L1、上端固定椎、下端固定椎和S1椎体的CT值,收集年龄、性别、体重指数(body mass index,BMI)、糖尿病史、手术节段数、两端融合方式、是否固定到S1等资料。以组内相关系数评估CT值测量的一致性,以Logistic回归分析判断CT值与螺钉松动的关系,以受试者工作特征(receiver operating characteristic,ROC)曲线分析评估CT值对螺钉松动的预测价值,由于松动组例数较少,组内CT值非正态分布,因此以中位数而非均值作为松动高危者预测的界值。结果:共53例患者出现螺钉松动,松动率17.8%(53/297)。上端椎螺钉松动组21例,对照组276例;下端椎螺钉松动48例,对照组249例。共有24例患者出现不融合,总体融合率91.9%(273/297),其中上端节段融合率93.6%(278/297),下端节段融合率93.3%(277/297)。椎体CT值测量具有可靠的测量者内一致性和测量者间一致性(ICC>0.8,P<0.001)。与上端椎对照组相比,上端椎松动组的上端椎体CT值更低(87.3±41.9HU vs 140.5±55.9HU,P<0.05);当下端固定至腰椎时,下端椎松动组的下端椎体CT值低于对照组(121.9±39.9HU vs 152.2±54.5HU,P<0.05);当下端固定至S1时,下端椎松动组的S1椎体CT值低于对照组(216.4±61.1HU vs 254.8±81.7HU,P<0.05)。上端椎、下端腰椎和S1的松动组椎体CT值中位数分别为75HU、110HU、220HU。椎体CT值是端椎螺钉松动的独立影响因素(上端椎:OR,0.979;95%CI,0.967-0.992下端椎:OR,0.990;95%CI,0.983~0.998)。端椎CT值可用于松动预测(AUC>0.6,P<0.05)。结论:椎体CT值是腰椎短节段内固定术后端椎螺钉松动的独立影响因素,CT值越低,发生螺钉松动风险越高。展开更多
基金supported by the National Natural Science Foundation of China ( 31670957)
文摘Objective To investigate the effectiveness of the micro-dynamic pedicle screw for the prevention of loosening between the screw and bone surface in lumbar spinal fusion.For this evaluation,the peek pull-out force(PPF)after fatigue resistance testing at different cycles and semidiameter of screw insertion area of micro-CT image was compared between the micro-dynamic and traditional pedicle screws.Methods Forty lumbar vertebrae received a traditional pedicle screw on one side and a micro-dynamic pedicle screw on the other side as follows:15 vertebrae underwent instant pull-out testing(group A,traditional vs.group B,micro-dynamic);15 vertebrae underwent pull-out test after 5000-cyclic fatigue loading(group C,traditional vs.group D,micro-dynamic);and 10 vertebrae underwent pull-out test after 10000-cyclic fatigue loading(group E,traditional vs.group F,micro-dynamic).All vertebrae that after fatigue loading were scanned by using micro-ct to check the semidiameter of screw insertion area.The PPF,normalized PPF(PPFn),bone mineral density(BMD)and diameter of screw insertion area were compared between all groups.Results The BMD showed a weak significant correlation with PPF(r=0.252,P=0.024).The PPF in groups A and B(P=0.485),and groups C and D(P=0.184)did not show significant difference.However,the PPF in group F was significantly greater than that measured in group E(P=0.005).The PPFn of groups A,C,and E significantly decreased as the number of cycles increased(P=0.015).Meanwhile,the PPFn of groups B,D,and F remained consistent regardless of the number of cycles(P=0.367). The semidiameter of traditional pedicle screw insertion area was significantly larger than that of micro-dynamic pedicle screw insertion area(P<0.001).Conclusions This study compared the performance of a micro-dynamic pedicle screw versus that of a traditional pedicle screw using pull-out testing and micro-CT.The results showed that the micro-dynamic pedicle screw provides similar resistance in lowcycle fatigue testing and favorable resistance in high-cycle fatigue testing versus the traditional pedicle screw.The micro-dynamic pedicle screw provides stronger fixation stability versus the traditional pedicle screw,especially in high-cyclic fatigue loading condition versus the traditional pedicle screws.
文摘Objective: It is important and helpful for surgeons to understand the correlation between spinal anatomy and screw trajectory before surgery. We aimed to assess a simple technique using 3D imaging software available on the hospital intranet for visual and quantitative feedback to prepare surgeons for an appropriate entry point and safe trajectory when placing cervical screws. Methods: A total of 59 cervical screws were inserted from C1 to T1 in 12 consecutive patients using this technique. First, a single CT optimal slice was selected from 3D CT images of the cervical spine to determine the intervals of bilateral entry points and lateral angle. Next, this 3D image was rotated to the lateral angle. Finally, bone was cut out on the entry point using subtractive manipulation, which removed the core of the pedicle or lateral mass. Screw trajectory was indicated, and surgeons could assess the correlation between surface landmarks, spinal anatomy, and screw trajectory. Posterior cervical fusion was performed using fluoroscopy. Postoperative outcomes and incidence of complications were retrospectively assessed. Results: One perforation (1.4%) was identified on postoperative CT images. No vascular injuries occurred. Differences in the intended entry point location and lateral angle of the screw from actual postoperative values were 1.49 ± 1.23 mm and 5.46。 ± 4.46。, respectively. Conclusions: A novel 3D CT imaging assessment underwent in cervical screw fixation. This technique is easily accessible on the hospital intranet and provides training in cervical screw placement for fellows. Surgeons can simulate screw placement and share surgical strategy.
文摘Objective To explore the differences between anatomic and CT measurements for anterior transoral axial pedicle screw placement. Methods C2 vertebrae of 60 adult spines were measured anatomically,while 20 adult spine vertebrae were
文摘To explore the value of helical CT volume rendering technique (VRT) in post-operative evaluation of screw fixation of axis fractures.Methods There were 21 cases of screw fixation of axis fractures between February 2002 and May 2004 in the study including six cases with fractures on axis body,five on odontoid process and 10 on axis body and odontoid process.All cases received X-ray plain film,helical CT scanning,multi-planar reformatting(MPR) and VRT.Results Screw fixation through axis body and massa lateralis atlantis was performed in 10 cases and that through axis body and odontoid process in 11.VRT could clearly display full aperture of screw orbit,location of screw and angle of fixation and hence was superior to X-ray plain film and MPR.Multi-angle VRT displayed asymmetrical space of odontoid process and massa lateralis atlantis in four cases and medial deviation of 2～5 mm of half screw in screw fixation through axis body and massa lateralis atlantis in six.Conclusion VRT can eliminate false shadow of fixation screw,clearly display full aperture of screw orbit and hence supply improtant imaging evidence for post-operative evaluation of screw fixation of axis fractures.7 refs,1 fig,1 tab.
文摘目的:探讨椎体CT值与腰椎短节段内固定术后螺钉松动的关系,选取用于预测螺钉松动的CT临界值。方法:回顾性分析2006年7月~2015年6月在我院行腰椎短节段(≤2个椎间隙)内固定术且术前1个月内行腰椎三维重建CT检查,随访≥24个月的患者资料。共297例,男104例,女193例,年龄54.3±12.5岁(21~80岁),随访36.1±16.5个月(24~110个月)。以末次随访X线评估螺钉松动和融合情况,根据螺钉是否松动及螺钉松动的位置,分为上端椎螺钉松动组、上端椎螺钉对照组和下端椎螺钉松动组、下端椎螺钉对照组,另将下端椎螺钉按是否固定到S1分为两个亚组,并分别分析各亚组内松动组和非松动组的差异。测量L1、上端固定椎、下端固定椎和S1椎体的CT值,收集年龄、性别、体重指数(body mass index,BMI)、糖尿病史、手术节段数、两端融合方式、是否固定到S1等资料。以组内相关系数评估CT值测量的一致性,以Logistic回归分析判断CT值与螺钉松动的关系,以受试者工作特征(receiver operating characteristic,ROC)曲线分析评估CT值对螺钉松动的预测价值,由于松动组例数较少,组内CT值非正态分布,因此以中位数而非均值作为松动高危者预测的界值。结果:共53例患者出现螺钉松动,松动率17.8%(53/297)。上端椎螺钉松动组21例,对照组276例;下端椎螺钉松动48例,对照组249例。共有24例患者出现不融合,总体融合率91.9%(273/297),其中上端节段融合率93.6%(278/297),下端节段融合率93.3%(277/297)。椎体CT值测量具有可靠的测量者内一致性和测量者间一致性(ICC>0.8,P<0.001)。与上端椎对照组相比,上端椎松动组的上端椎体CT值更低(87.3±41.9HU vs 140.5±55.9HU,P<0.05);当下端固定至腰椎时,下端椎松动组的下端椎体CT值低于对照组(121.9±39.9HU vs 152.2±54.5HU,P<0.05);当下端固定至S1时,下端椎松动组的S1椎体CT值低于对照组(216.4±61.1HU vs 254.8±81.7HU,P<0.05)。上端椎、下端腰椎和S1的松动组椎体CT值中位数分别为75HU、110HU、220HU。椎体CT值是端椎螺钉松动的独立影响因素(上端椎:OR,0.979;95%CI,0.967-0.992下端椎:OR,0.990;95%CI,0.983~0.998)。端椎CT值可用于松动预测(AUC>0.6,P<0.05)。结论:椎体CT值是腰椎短节段内固定术后端椎螺钉松动的独立影响因素,CT值越低,发生螺钉松动风险越高。
