The effect of tranexamic acid on artificial joint materials: a biomechanical study (the bioTRANX study)

Background

Tranexamic acid (TXA) has been successfully used to reduce bleeding in joint replacement. Recently local TXA has been advocated to reduce blood loss in total knee or hip replacement; however, this raised concerns about potential adverse effects of TXA upon the artificial joint replacement.

Materials and methods

In this biomechanical study we compared the effects of TXA and saline upon the following biomechanical properties of artificial joint materials—(1) tensile properties (ultimate strength, stiffness and Young’s modulus), (2) the wear rate using a multi-directional pin-on-plate machine, and (3) the surface topography of pins and plates before and after wear rate testing.

Results

There were no significant differences in tensile strength, wear rates or surface topography of either ultra-high-molecular-weight polyethylene pins or cobalt chromium molybdenum metal plates between specimens soaked in TXA and specimens soaked in saline.

Conclusion

Biomechanical testing shows that there are no biomechanical adverse affects on the properties of common artificial joint materials from using topical TXA.

Level of evidence

V     

负载 rhBMP-2钙磷硅基活性骨修复材料的3D 打印构建及生物学性能研究

目的构建一种新型钙磷硅基活性骨修复材料,研究材料成分、孔道结构和是否负载生长因子对支架力学性能、细胞黏附性能和骨组织形成过程的影响。方法以磷酸钙骨水泥（C PC ）、介孔硅酸钙（MCS）为原料,采用3D打印技术构建不同孔道结构的MCS／CPC复合支架,在扫描电子显微镜下观察支架内部孔道结构,通过万能力学试验机测试各组支架的最大抗压力学性能,用四甲基偶氮唑盐法测试各组支架的细胞黏附性能。建立大鼠颅骨原位缺损修复模型,在支架上负载重组人骨形态发生蛋白（rhBMP）‐2制备得到钙磷硅基活性多孔支架（MCS／CPC／rhBMP‐2）,考察CPC、MCS／CPC和MCS／CPC／rhBMP‐2支架的组织相容性与成骨性能。结果采用3D打印技术能够实现对钙磷硅基骨修复支架内部孔道结构的可控制备。垂直孔设计大小为350μm 的MCS／CPC支架具有适宜的孔隙率和抗压力学强度（分别为56．6％和9．8 M Pa）;细胞相容性良好,有利于细胞黏附。负载rhBM P‐2可显著加快新生骨组织形成,植入MCS／CPC／rhBMP‐2复合支架初期纤维组织即可在连通孔道中自由生长,在植入12周后,MCS／CPC／rhBMP‐2支架新生骨面积明显高于CPC和MCS／CPC支架,且新生骨组织形成过程与颅骨膜内成骨过程相似,具有一定的仿生效应。结论采用3D打印法制备的 M CS／CPC／rhBM P‐2支架材料具有规则的连通孔道,力学性能良好,促进成骨效果优异,是理想的新型骨缺损修复材料。     

Does tunica anatomy matter in penile implant?

Background

Overall prosthesis survival is important in penile implant, which remains the final viable solution to many patients with refractory erectile dysfunction (ED). This paper is to retrospectively study the role of the anatomy of tunica albuginea (TA).

Methods

From March 1987 to March 1991 while the TA was regarded as a circumferential single layer, 21 organically ED men, aged from 27 to 77, received penile prosthesis implantation and were allocated to conventional group. From August 1992 to March 2013 while the tip of Hegar’s dilator was categorically directed medial-dorsally during corporal dilatation derived from newfound TA as a bi-layered structure with a 360° complete inner circular layer and a 300° incomplete outer longitudinal coat, 196 ED males, aged from 35 to 83, underwent penile implant and were categorized to advanced group. The model of prosthesis was recorded. Prosthesis loss rate and survival time were analyzed and the follow up period ranged from 22.4-26.4 (average 24.3) years and 0.4-20.6 (average 15.8) years to the conventional and advanced group respectively.

Results

To the conventional and advanced group, the number of inflatable and rigid type prosthesis used were 2, 19 and 15, 181 respectively, whereas the prosthesis loss was encountered in 50.0% (1/2), 15.8% (3/19) and 0.0% (0/15), 0.6% (1/181) respectively. And the prosthesis survival time were 5.1-6.3 (5.7) years, 1.3-26.4 (15.2) years and 6.1-16.2 (11.2) years, 0.4-20.6 (15.3) years to the conventional and advanced group respectively. Statistical significance was noted on prosthesis loss in groups (P=0.01) while the Mentor Acuform stood out in prosthesis survival.

Conclusions

Anatomy-based managing maneuver appears to deliver better surgery success in penile implant. Tunica anatomy is significant in performing implant surgery.     

Cation Exchange Resins and colonic perforation. What surgeons need to know

IntroductionSince 1961 the use of Cation Exchange Resins has been the mainstream treatment for chronic hyperkalemia. For the past 25 years different kind of complications derived from its clinical use have been recognized, being the colonic necrosis the most feared and lethal of all.Presentation of caseWe report a case of a 72-year-old patient with chronic kidney disease, treated with calcium polystyrene sulfonate for hyperkalemia treatment who presented in the emergency department with constipation treated with hypertonic cathartics. With clinical deterioration 48 h later progressed with colonic necrosis requiring urgent laparotomy, sigmoidectomy and open abdomen management with subsequent rectal stump perforation and dead. The histopathology finding: calcium polystyrene sulfonate embedded in the mucosa, consistent with the cause of perforation.DiscussionLillemoe reported the first case series of five uremic patients with colonic perforation associated with the use of SPS in sorbitol in 1987 and in 2009 the FDA removed from the market the SPS containing 70% of sorbitol.The pathophysiologic change of CER goes from mucosal edema, ulcers, pseudomembranes, and the most severe case transmural necrosis.Up to present day, some authors have questioned the use of CER in the setting of lowering serum potassium. Despite its worldwide use in hyperkalemia settings, multiple studies have not demonstrated a significant potassium excretion by CER.ConclusionDespite the low incidence of colonic complication and lethal colonic necrosis associated with the CER clinical use, the general surgeon needs a high index of suspicion when dealing with patients treated with CER and abdominal pain.     

射频辅助肝切除术与单纯性肝切除术治疗肝细胞性肝癌的前瞻性随机对照研究

目的 比较射频辅助肝切除术和单纯性肝切除术治疗肝细胞性肝癌的围手术期疗效.方法 术前采用随机数字表法将2012年12月至2014年10月在第三军医大学西南医院住院的92例肝癌患者随机性分配到两个治疗组中,其中射频辅助肝切除术组(RF+ LR) 46例,单纯性肝切除术组(LR)46例.观察的主要疗效指标是各组患者术中的出血量和肝门阻断时间;次要疗效指标是术后肝功能、并发症发生率、死亡率和住院时间.结果 平均失血量在射频辅助肝切除术组(RF+ LR)低于单纯性肝切除术组(LR,300 mL vs 400 mL,P=0.049);肝门阻断的时间在RF+ LR组明显降低(10 rain vs15 min,P=0.014).术后肝功能和总体的并发症发生率两组间无统计学差异(P＞0.05),住院时间RF+ LR组明显缩短(18.5 dvs 22.5 d,P=0.002).两组均无死亡的患者.结论 射频辅助肝切除术在肝细胞性肝癌的治疗中能够有效地减少术中出血量、肝门阻断时间和住院时间,但是对于肝硬化重的患者应慎用.     

Calcium Antagonists in Patients with Type 2 Diabetes and Hypertension

Hypertension is twice as common in patients with diabetes compared to those without diabetes. It accounts for up to 75% of cardiovascular disease risk leading to the substantial increase in morbidity and mortality. Control of blood pressure in people with diabetes has been shown in randomized controlled trials to decrease cardiovascular risk and improve outcome especially in preventing stroke. A target blood pressure goal of <130/80 mm Hg is currently recommended for patients with diabetes. However, less than 1/3 of these patients achieve such a goal. This is in part due to the inherent difficulty in controlling blood pressure in these patients where hypertension is usually associated with increased salt sensitivity, volume expansion and isolated systolic hypertension. Therefore, patients with diabetes usually require multiple medications for optimal blood pressure control. Calcium channel antagonists have been shown in large clinical trials to be both safe and effective in controlling blood pressure in diabetic patients and will continue to play a major role in the management of hypertension in this population, particularly in the combination therapy that these patients usually require.     

Defaulters from antiretroviral treatment in Jimma University Specialized Hospital, Southwest Ethiopia

Objective To determine the prevalence of and factors associated with defaulting from antiretroviral treatment (ART) in Jimma, Ethiopia. Methods Unmatched case control study: cases were individuals who had missed two or more clinical appointments (i.e. had not been seen for the last 2 months) between January 2005 and February 2007; controls were individuals who had been on ART at least for 1 year and were rated as excellent adherers by the providers. Data were collected from patient records, and by telephone call and home visit to identify the reason for defaulting. Results Of 1270 patients who started ART, 915 (72.0%) were active ART users and 355 (28.0%) had missed two or more clinical appointments. The latter comprised 173 (13.6%) defaulters, 101 (8.0%) who transferred out, 75 (5.9%) who died, and 6 (0.5%) who restarted ART. Reasons for defaulting were unclear in most cases. Reasons given were loss of hope in medication, lack of food, mental illness, holy water, no money for transport, and other illnesses. Tracing was not successful because of incorrect address on the register in 61.6% of the cases. Taking hard drugs (cocaine, cannabis and IV drugs), excessive alcohol consumption, being bedridden, living outside Jimma town and having an HIV negative or unknown HIV status partner were associated with defaulting ART. Conclusion A significant proportion of patients defaulted from ART treatment. ART clinics should ensure that patients’ addresses are correct and complete. Programmatic and counseling efforts to decrease ART defaulting should address illicit drug and excessive alcohol use, decentralise ART services, institute home‐based treatment options for seriously ill and bedridden patients, and address patients concerns.