Effect of tranexamic acid on platelet ADP during extracorporeal circulation

Seventeen adults received the antifibrinolytic drug tranexamic acid during cardiac surgery utilizing extracorporeal circulation (ECC). In 8 patients, drug administration began prior to skin incision (pre-ECC); infusions commenced after ECC and protamine administration in another 9 patients (post-ECC). Compared with the post-ECC group, the pre-ECC group exhibited less bleeding via mediastinal drains (420 vs. 655 mL/12 h median, P = 0.024), decreased frequency of the presence (greater than or equal to 10 micrograms/mL) of fibrin split products (P less than 0.05), and greater platelet dense granule content of adenosine diphosphate after surgery (15.47 vs. 4.05 nmoles/mg protein median, P = 0.021). Follow-up in vitro study of tranexamic acid inhibition of plasmin-induced platelet activation utilizing normal human platelet rich plasma and porcine plasmin revealed a 13-fold lower concentration of tranexamic acid for 50% inhibition when plasmin was preincubated with the drug (1.2 micrograms/mL, 95% CI = 1.13-1.60 micrograms/mL) compared to when platelet rich plasma was preincubated with the drug (16 micrograms/mL, 95% CI = 7.3-99. micrograms/mL). Plasmin inactivated with tranexamic acid retained its ability to inhibit thrombin-induced platelet activation, thus suggesting that tranexamic acid inhibits plasmin's catalytic activity and not its binding to platelets. Both clot lysis and platelet dysfunction may contribute to bleeding after ECC. Tranexamic acid blocks plasmin-induced partial platelet activation during ECC, thus preserving platelet function and promoting hemostasis after ECC.     

Effects of nerve compression on fast axonal transport in streptozotocin-induced diabetes mellitus

Summary The hypothesis that nerves in diabetes mellitus exhibit an increased susceptibility to compression was experimentally tested. Inhibition of fast axonal transport was induced by local compression in sciatic nerves of rats with streptozotocin-induced diabetes mellitus. Fast anterograde axonal transport was measured after application of³H-leucine to the motor neurone cell bodies in the spinal cord. The sciatic nerve as subjected to local, graded compression in vivo by a small compression chamber. The amount of accumulation of proteins was quantified by calculation of a transport block ratio. Compression at 30 mm Hg for 3 h induced a significantly greater (p<0.05) accumulation of axonally transported proteins at the site of compression in nerves of diabetic animals (transport block ratio: 1.01±0.35; n=7) than in nerves of controls (0.67±0.16;n=7). Accumulation was significantly higher in ligature experiments of both control (1.34±0.44;n=8;p< 0.01) and diabetic animals (1.45±0.30;n=8 ;p< 0.05), indicating that the block of transport in compressed nerves was incomplete. Neither sham compressed diabetic (0.50±0.09;n=6) nor control (0.49±0.11;n=6) nerves showed any block of axonal transport. The possible causes of the increased inhibition of fast axonal transport in diabetic rats are discussed. The results indicate that diabetes may lead to an increased susceptibility of peripheral nerves to compression.     

Best Practices for the Prevention of Radial Artery Occlusion After Transradial Diagnostic Angiography and Intervention: An International Consensus Paper

Transradial access (TRA) is increasingly used worldwide for percutaneous interventional procedures and associated with lower bleeding and vascular complications than transfemoral artery access. Radial artery occlusion (RAO) is the most frequent post-procedural complication of TRA, restricting the use of the same radial artery for future procedures and as a conduit for coronary artery bypass graft. The authors review recent advances in the prevention of RAO following percutaneous TRA diagnostic or interventional procedures. Based on the available data, the authors provide easily applicable and effective recommendations to prevent periprocedural RAO and maximize the chances of access in case of repeat catheterization or coronary artery bypass grafting surgery.     

Cathepsins B and L Increased during Response of Periodontal Ligament Cells to Mechanical Stress In Vitro

Cathepsin is a typical and well-characterized lysosomal cysteine protease that, under pathological conditions, is involved in tissue destruction. A recent immunocytochemical study demonstrated that cathepsins B (CAB) and L (CAL) were localized in the periodontal ligament (PDL) of the rat molar, and they were expressed in compressed sites during experimental tooth movement. Further, we demonstrated previously that the levels of CAB and CAL in gingival crevicular fluid increased during orthodontic tooth movement. Therefore, CAB and CAL may play important roles in the process of collagen degradation during orthodontic tooth movement, and our in vitro study examined the secretion of CAB and CAL in PDL cells following mechanical stress. PDL cells were subjected to 0.5, 1.0, 2.0, or 3.0 g/cm² of compression force or an increase in surface area by tension force of 0.28%, 0.95%, 1.72%, or 2.50% for 24 hr. For detection of CAB and CAL in conditioned medium, commercially available ELISA kits were used. We found compression and tension significantly increased the secretions of both CAB and CAL in PDL cells, which were exhibited in a time- and force magnitude-dependent manner. The compression-stimulated secretion of CAB was increased approximately 3-fold and that of CAL 4-fold, as compared with the control. Further, tension-stimulated secretion of CAB was increased by 1.5-fold and that of CAL 2-fold compared with the control. When analyzed using a semiquantitative polymerase chain reaction assay, CAB and CAL mRNA were increased in response to both compression and tension forces. These findings demonstrated that mechanical stress (compression and tension forces) causes an increase in secretion of CAB and CAL in PDL cells in vitro.     

Endoscopically assisted proximal radial nerve decompression: Surgical technique

State of the artThe proximal radial nerve compression syndrome includes supinator syndrome and proximal radial nerve constrictions. This article presents a new endoscopic assisted radial nerve decompression surgical technique described for the first time by Leclère et al. in 2013.Surgical techniqueEndoscopic scissor decompression of the proximal radial nerve is always performed under plexus anaesthesia. It includes 8 key steps documented in this article. We review the indications and limitations of the surgical technique.ConclusionEarly clinical results after endoscopic assisted decompression of the radial nerve appear excellent. However, they still need to be compared with conventional techniques. Clinical studies are likely to widely develop because of the mini-invasive nature of this new surgical technique.     

Bone Cement Dislodgement: One of Complications Following Bone Cement Augmentation Procedures for Osteoporotic Spinal Fracture

Bone cement augmentation procedures have been getting more position as a minimally invasive surgical option for osteoporotic spinal fractures. However, complications related to these procedures have been increasingly reported. We describe a case of bone cement dislodgement following cement augmentation procedure for osteoporotic spinal fracture by reviewing the patient''s medical records, imaging results and related literatures. A 73-year-old woman suffering back and buttock pain following a fall from level ground was diagnosed as an osteoporotic fracture of the 11th thoracic spine. Percutaneous kyphoplasty was performed for this lesion. Six weeks later, the patient complained of a recurrence of back and buttock pain. Radiologic images revealed superior dislodgement of bone cement through the 11th thoracic superior endplate with destruction of the lower part of the 10th thoracic spine. Staged anterior and posterior fusion was performed. Two years postoperatively, the patient carries on with her daily living without any significant disability. Delayed bone cement dislodgement can occur as one of complications following bone cement augmentation procedure for osteoporotic spinal fracture. It might be related to the presence of intravertebral cleft, lack of interdigitation of bone cement with the surrounding trabeculae, and possible damage of endplate during ballooning procedure.     

Compression screw fixation without bone grafting for scaphoid fibrous nonunion

Purpose

Bone graft is often recommended as an adjuvant for treatment of scaphoid nonunions. However, recent literature has suggested that fibrous nonunion may be suited to treatment with rigid fixation without bone grafting. This work reported on outcomes of compression screw fixation for established scaphoid fibrous nonunions without bone graft.

Methods

Fourteen patients underwent surgical compression screw fixation without bone grafting of scaphoid fibrous nonunion between January 1, 2000, and December 31, 2012, with minimum follow-up until the time of clinical and radiographic healing. Fibrous nonunion of the scaphoid was defined as a scaphoid fracture with all of the following features: (1) persistent tenderness, (2) incomplete trabecular bridging on three X-ray views, (3) injury that had occurred at a minimum of 6 months prior to surgery, and (4) identification of fibrous union at the time of surgery. Outcomes were assessed with range of motion assessment, Disability of the Arm, Shoulder and Hand (DASH) scores, and plain radiographs.

Results

Twelve of the 14 patients healed successfully, while two patients required secondary vascularized bone grafting. Both unhealed patients sustained proximal pole fractures and had a duration of ≥1 year from injury to surgery. Average time to healing was 4.4 ± 2.0 months. Average flexion was 73 ± 22° and average extension was 66 ± 22° postoperatively. Average grip strength was 90 ± 25 lbs on the operative side. Mean postoperative pain score was 1.4 (range, 0 to 7). Mean postoperative DASH score was 10.2 (range, 0 to 52). Increasing age and an interval from injury to surgery of >1 year correlated with worse DASH and pain scores.

Conclusions

Patients with fibrous scaphoid nonunion demonstrated good results with rigid fixation without bone grafting. Increasing age and >1-year interval between injury and surgery resulted in lower self-assessed outcomes.

Level of Evidence

Therapeutic Level IV, retrospective case series     

P物质、降钙素基因相关肽、白介素6与椎体骨折并发远隔部位疼痛的相关性研究

目的探讨胸腰段椎体压缩骨折出现远隔部位疼痛的病因。方法选取Denis分类屈曲型骨折的手术病例62例,腰痛伴远隔部位疼痛11例为实验组,腰痛不伴远隔部位疼痛51例为对照组。术中取多裂肌标本,制作冰冻切片,P物质(SP)、降钙素基因相关肽(CGRP)、白介素6(IL-6)抗体免疫组化染色;计算椎体前缘高度和后缘高度的比值来衡量伤椎的压缩程度;手术前及手术后2周分别行VAS、JOA、ODI评分。结果实验组:术前椎体压缩程度(68.73±11.91)%、VAS(8.09±1.51)分、ODI(40.45±3.48)%、JOA(14.00±3.80)分,术后椎体压缩程度(84.00±6.08)%、VAS(5.00±1.34)分、ODI(21.73±3.80)%、JOA(15.36±3.56)分;对照组:术前椎体压缩程度(75.27±14.14)%、VAS(7.65±1.43)分、ODI(39.24±4.64)%、JOA(11.90±3.59)分,术后椎体压缩程度(83.75±8.89)%、VAS(2.76±1.18)分、ODI(15.82±3.65)%、JOA(20.84±3.71)分。实验组与对照组术前椎体压缩程度比较,差异无统计学意义(P0.05),术后椎体压缩程度比较,差异无统计学意义(P0.05)。实验组与对照组术前VAS、ODI、JOA评分差异无统计学意义(P0.05),术后VAS、ODI、JOA评分对照组优于实验组(P0.05)。免疫组化:实验组11例标本SP、CGRP、IL-6染色结果均为阳性。对照组51例标本SP、CGRP、IL-6染色结果阴性。结论屈曲暴力造成脊柱后方组织损伤,SP、CGRP、IL-6介导的炎症反应刺激脊神经后支,是产生远隔部位疼痛的重要原因。     

Gelatamp胶质银明胶海绵在前牙区Ⅱ型种植位点的临床应用研究

目的:观察Gelatamp胶质银明胶海绵在前牙区Ⅱ型种植位点的临床应用效果。方法:选择40例前牙区拔牙拟作Ⅱ型种植的病人,随机分层分为Gelatamp胶质银明胶海绵填塞止血组(试验组)及棉球压迫止血组(对照组)。拔牙后,试验组在牙槽窝置入Gelatamp胶质银明胶海绵,对照组常规紧咬棉球30分钟后取出,观察比较两组的止血效果和4周后行Ⅱ型种植手术前拔牙位点软组织愈合的情况。结果:试验组拔牙创出血很快停止,出血平均时间为0.67分,试验组、对照组止血效果有效率分别为100%,80%,差异有统计学意义(P<0.05)。在4周后Ⅱ型种植手术前试验组、对照组的软组织愈合良好率分别为70%和40%,差异有统计学意义(P<0.05)。结论:Gelatamp胶质银明胶海绵,能显著缩短出血时间,有效增强止血效果,具有止血和持久杀菌的双重效果,有利于形成良好的软组织,有利于早期种植体植入后封闭创面,具有一定的临床应用价值。