股骨远端骨折锁定钢板断裂原因分析及处理

目的探讨股骨远端骨折锁定钢板内固定失效的原因及防治措施。方法对2007年5月~2012年6月共14例应用锁定钢板固定失败的股骨远端骨折患者的临床资料进行分析,其中男9例,女5例,年龄27~68岁,平均39.2岁,骨折内固定术后1~8月(平均5.6个月)锁定钢板断裂。钢板断裂者均采用钢板螺钉取出术,5例予交锁髓内钉内固定,9例再次锁定钢板固定,均同时取自体髂骨移植植骨治疗。结果二次术后14例均获得随访,术后随访9~24月,平均14月,13例获得骨性愈合,1例二次锁定钢板固定患者于二次术后8月再次发生钢板断裂,予行钢板螺丝钉取出、交锁髓内钉固定治疗,再次手术后6月获骨性愈合。膝关节功能按Kolment评分标准:优4例,良9例,差1例。断裂原因具有多样性,5例钢板选择过短,9例存在螺钉置入密度过大,8例内侧皮质粉碎、缺失,4例因过早负重,2例因锻炼时摔伤而导致内固定失败。结论锁定钢板内固定失效的原因通常与对锁定钢板的适应证掌握不全,骨折端过度剥离、复位不良或内侧皮质存在缺损及术后功能锻炼不当有关。因此,选择合适的内固定物,注重植骨,加强术后康复指导、避免过早负重可有效预防及治疗股骨远端骨折钢板内固定失败。     

A case of premature ovarian insufficiency in Nijmegen breakage syndrome patient and review of literature. From gene mutation to clinical management

Abstract

Background: Nijmegen breakage syndrome (NBS) is an autosomal recessive disorder leading to chromosomal instability and an array of symptoms, including characteristic facial features (bird-like face), predisposition to malignancies, as well as hypergonadotropic hypogonadism. This case report discusses the diagnostic process and management of a 23-year-old Polish female patient who was admitted to hospital with symptoms of secondary amenorrhea and clinical features corresponding to NBS.

Methods: Clinical examination, per-rectal ultrasound, laboratory diagnostics (including serum concentrations of FSH, LH, estradiol, testosterone, and TSH), as well as SSCP analysis and classic karyotyping were performed.

Results: During hormonal evaluation elevated serum concentration of FSH and LH and decreased serum concentration of estradiol were measured. The genetic testing revealed translocation 7;14 (t(7;14)) and inversion 7 in 22% of examined cells which confirmed the initial hypothesis of NBS. The diagnosis was finally verified by identifying a Slavic founder mutation, c.657_661del5, on both allels of the NBN gene. Furthermore, hormonal serum evaluation conducted after four weeks allowed the patient to be diagnosed with premature ovarian insufficiency (POI) suspected earlier on the grounds of preliminary examinations (ultrasound imaging and laboratory tests).

Conclusions: Chromosomal instability resulting from a mutation present in Nijmegen breakage syndrome patients might be a causative factor of premature ovarian insufficiency. Therefore, females diagnosed with NBS should undergo additional diagnostic procedures in order to determine further management and treatment.     

Video versus lecture: effective alternatives for orthodontic auxiliary training.

Abstract

Many studies have compared the relative effectiveness of visually-aided lectures and videotapes, but methodological flaws have prevented definitive comparison of the techniques. This study assessed the relative effectiveness of the two approaches for orthodontic auxiliary training. This study was a prospective, randomised trial, conducted at the Eastman Dental Hospital and Institute. Two groups of 16 dental auxiliaries, selected at random, studied identification and positioning of orthodontic brackets: one group attended a lecture accompanied by slides and the other viewed a video. Subjects bonded brackets onto acrylic teeth and the results were assessed by computerised image analysis. The subjects completed a questionnaire on their attitudes to the respective teaching methods. Results were assessed for accuracy of bracket placement and variations in type of auxiliary. There was no significant difference between the teaching methods except for bracket positioning where video was slightly better (P < 0.05). There was no significant difference between the types of auxiliary. Generally, video teaching and lecturing were equally effective, with video achieving slightly better results. Both methods were effective at teaching bracket placement, and dental nurses and student hygienists proved equally adept at bracket positioning.     

阻钉技术对交锁髓内钉断钉的影响

目的探讨阻钉技术对交锁髓内钉断钉的预防作用。方法2003年1月~2005年8月,采用交锁髓内钉固定长骨干骨折56例,男32例,女24例。年龄21~65岁,平均34岁。其中股骨骨折26例,胫骨骨折30例,均为新鲜、闭合性骨折。骨折类型:中部横断骨折10例,中部短斜形骨折11例,中部长斜形或螺旋形骨折20例,远、近1/3骨干骨折15例。前期32例患者采用常规的交锁髓内钉固定骨折(组),后期24例中部长斜形或螺旋形骨折及远、近1/3骨折患者采用交锁髓内钉配合阻钉固定骨折(组)。结果获随访12~21个月,平均16个月。组3例患者骨折未愈合,其中1例股骨中部长斜形骨折主钉在骨折线附近断裂,另2例胫骨远1/3骨折主钉在靠近骨折端的第1个锁钉孔处断裂;其余患者术后6~12个月获骨性愈合,但骨折处出现较多骨痂。组患者于术后3~8个月获骨性愈合,骨折对位、对线良好,无断钉发生。结论阻钉技术配合交锁髓内钉应用可明显增强骨折断端稳定性,减少断钉发生。     

Male condoms that break in use do so mostly by a "blunt puncture" mechanism

BACKGROUND: Published condom breakage studies typically report the percentage of failures but rarely provide any evidence on the mechanism of failure. METHODS: Over a period of 7 years, broken condoms returned to a supplier (SSL, Durex) via consumer complaints were examined to determine the cause of failure. Also, some consumers who reported breakage but did not return condoms were sent a questionnaire on the causes of breakage. Finally, theories proposed for the mechanism of breakage were investigated on a laboratory coital model. RESULTS: Nearly 1000 (n=972) returned condoms made from natural rubber and polyurethane were examined. Visible features on those that were broken, were classified. Evidence combined from examining returns, questionnaire responses and the coital model strongly suggests a single predominant mechanism of failure we named "blunt puncture," where the tip of the thrusting male penis progressively stretches one part of the intact condom wall until it ultimately breaks. CONCLUSIONS: Blunt puncture appears to be the mechanism of breakage responsible for more than 90% of condom breakage not attributable to misuse. Knowledge of the main mechanism of breakage should help develop better user instructions, better test methods and, ultimately, better condoms.     

胸腰椎骨折内固定术后椎弓根螺钉断裂的原因分析及对策

目的：探讨胸腰椎骨折内固定术后椎弓根螺钉断裂的原因以及预防措施。方法：对2000年6月至2006年9月应用椎弓根螺钉内固定系统治疗的273例资料完整的胸腰椎骨折病例进行回顾性分析,按照骨折类型、植骨融合方式、是否使用横杆以及内固定取出时间对椎弓根螺钉断裂者进行统计学分析。结果：发生椎弓根螺钉断裂22例，椎弓根螺钉断裂平均发生时间为术后19．9个月，大多（19／22）在取内固定物前复查X线片时发现。断钉发生率：爆裂型骨折患者（13／76）显著高于压缩型骨折（6／132）和骨折脱位型患者（3／65）（P〈0．01）；椎间植骨组（1／25）和后外侧植骨组（7／110）显著低于未植骨组（7／70）（P〈O．05）；未使用横杆组（8／49）显著高于使用横杆组（14／224）（P〈O．05）；术后12个月以上取出内固定组（9／97）高于6～12个月取出内固定组（6／169）（P〈O．05）。结论：椎弓根螺钉断裂可能与手术方式选择不当、植骨融合不当、未正确使用横连杆、内置物取出过迟有关。严格掌握手术适应证和手术时机、有效植骨融合、合理使用横杆以及及时取出内固定可有效防止椎弓根螺钉断裂发生。     

Characterization of the grinding behaviour in a single particle impact device: Studies on pharmaceutical powders

The grinding behaviour of different materials can be described by the two material parameters f_Mat and W_m,min [Vogel, L., Peukert, W., 2003. Breakage behaviour of different materials—construction of a mastercurve for the breakage probability. Powder Technol. 129, 101–110]. f_Mat describes the resistance of particulate material against fracture in impact comminution, W_m,min characterizes the specific energy which a particle can take up without comminution. The material parameters are determined experimentally by single particle impact tests. This concept is also applicable to pharmaceutical powders, as will be shown in this work. A device is presented for the characterization of particles with sizes down to a few 10 μm. Particles are dispersed and accelerated in an air stream which is flowing against an impact plate. The impact velocity is controlled by the air flow. An LDA system enables the measurement of particle velocities. The results obtained with this jet mill are in accordance to those obtained from another single particle impact device used by Vogel and Peukert, in which the influence of fluid flow is completely avoided. Since the new device is especially designed for finer powders, it will allow a more detailed analysis of the material parameters at smaller particle sizes. Additionally, a new analysis method has been developed in order to determine the breakage probability not from sieve analysis but from laser light diffraction (LLD) data by using a population balance.