优化供者临床管理策略，推动供者管理的科学研究

供者管理是器官捐献与移植流程的核心环节,提高潜在供者的临床管理质量、降低潜在供者流失率、提高捐献器官利用率是缓解移植器官短缺的有效措施。为促进供者临床管理的发展,在保障供、受者健康权益的前提下不断提高捐献器官的利用率,本文就脑死亡器官捐献者管理的临床特征和管理要点、供者维护临床研究的现状及未来发展作一综述。     

Cementless total knee arthroplasty: Patient selection and surgical techniques to optimize outcomes

Cementless fixation is a reliable, durable fixation option for patients undergoing primary TKA and is especially attractive for younger and more active patients. Advances in fixation materials such as modern highly porous metals provide an additional adjunct in promoting osseointegration and longer-term success. Proper patient selection, adequate exposure, meticulous surgical technique, and modern implant designs are significant factors for enacting a successful outcome. This article outlines the essential elements and details the surgical techniques that should be considered to facilitate optimal results when utilizing cementless fixation in TKA.     

Management to optimize organ procurement in brain dead donors

The demand for donor organs continues to exceed the number of organs available for transplantation. Many reasons may account for this discrepancy, such as the lack of consent, the absence of an experienced coordinator team able to solve logistical problems, the use of strict donor criteria, and suboptimal, unstandardized critical care management of potential organ donors. This has resulted in efforts to improve the medical care delivered to potential organ donors, so as to reduce organ shortages, improve organ procurement, and promote graft survival. The physiological changes that follow brain death entail a high incidence of complications jeopardizing potentially transplantable organs. Adverse events include cardiovascular changes, endocrine and metabolic disturbances, and disruption of internal homeostasis. Brain death also upregulates the release of pro-inflammatory molecules. Recent findings support the hypothesis that a preclinical lung injury characterized by an enhanced inflammatory response is present in potential donors and may predispose recipients to an adverse clinical prognosis following lung transplantation. In clinical practice, hypotension, diabetes insipidus, relative hypothermia, and natremia are more common than disseminated intravascular coagulation, cardiac arrhythmias, pulmonary oedema, acute lung injury, and metabolic acidosis. Strategies for the management of organ donors exist and consist of the normalization of donor physiology. Management has been complicated by the recent use of 'marginal' donors and donors of advanced age or with 'extended' criteria. Current guidelines suggest that the priority of critical care management for potential organ donors should be shifted from a 'cerebral protective' strategy to a multimodal strategy aimed to preserve peripheral organ function.     

Demystifying sample-size calculation for clinical trials and comparative effectiveness research: the impact of low-event frequency in surgical clinical research

Background

Type II error, or not meeting sample-size requirement, has been identified as an issue in the surgical literature. The root of this problem is the low frequency of events in the majority of surgical clinical research. This exponentially increases the sample size needed to achieve statistical significance.

Methods

The methodology and mechanics of sample-size calculations are presented to demonstrate how sample-size requirements change based on baseline event rate and relative reduction in event rate. These concepts are then illustrated using real-life clinical scenarios.

Results

If a hypothetical baseline event rate is 1 % and the event rate in the experimental group is 0.5 % (therefore representing a 50 % reduction), then the total number of study patients required is 10,130. If the baseline event rate is 1 %, and the event rate in the experimental group is 0.9 % (a 10 % reduction), then the total number of study patients required is 299,410.

Conclusions

Sample-size calculations are affected by the frequency of the event or events of interest. Given advances in clinical medicine, many clinical outcomes of interest occur at very low frequencies. These low frequencies exponentially increase the sample size required to find statistically significant differences, making randomized clinical trials difficult to conduct properly. Surgical clinical researchers should advocate for the establishment of robust, prospective, large, multi-institutional clinical databases along with the establishment of proper outcomes research methodology as a way to augment randomized trials.     

Procedures for the use of neonatal rats in surgical research

The investigator using neonatal rodents in surgical research often encounters a variety of technical challenges such as the inhibition of maternal cannibalism, the coding of individual littermates, choice of anesthetics and meeting anesthetic overdose emergencies, the selection of injection and phlebotomy sites, and postoperative growth retardation. This communication describes procedures in use for overcoming these difficulties and emphasizes, wherever possible, nonpharmacological approaches to the surgical manipulation of very young animals and to their postoperative support.     

Study management strategies to optimize student- and trainee-led collaborative research

The collaborative research model is a powerful approach to answering surgical research questions that empowers and inspires medical students and trainees. The Opioid PrEscRiptions and usage After Surgery (OPERAS) study is a student- and trainee-led international multi-centre prospective cohort study developed in Australia and Aotearoa New Zealand. In this article, we will discuss (i) how the OPERAS study was conceptualized and structured; (ii) the channels through which information and education were communicated to collaborators; (iii) how data was stored in a secure and user-friendly fashion and (iv) the lessons learned and expected goals for the future. We aim to describe how collaborative research studies can be designed to support early career researchers to make valuable contributions to the literature.     

Posterior surgical approaches to the elbow: a comparative anatomic study

Triceps splitting, triceps reflecting, and olecranon osteotomy are the most common posterior surgical approaches to the adult elbow, but no comparative data exist as to the exposure provided by each approach. The aim of this study was to determine which of these approaches provides the greatest exposure of the distal humeral articular surface. Each approach was performed on 4 adult cadaveric elbows. After the completion of each approach, the visible articular surface was painted with methylene blue. The elbow was then disarticulated, and the percentage of articular surface visible was measured. The median exposed articular surface for the triceps splitting, triceps reflecting, and olecranon osteotomy approaches was 35%, 46%, and 57%, respectively. Olecranon osteotomy exposed more articular surface than the triceps splitting approach (Mann-Whitney test, P =.03) but was not significantly greater than the triceps reflecting approach. However, even the olecranon osteotomy approach failed to provide visualization of more than 40% of the distal humeral articular surface.     

Comparison of the effects of surgical and autologous fascial suture materials on testicular histology in rats subjected to orchiopexy

In this study orchiopexy was performed in 30 Sprague-Dawley rats in order to compare traumatic effects of surgical and autologous fascial suture materials on testicular histology. Abscess formation was observed in 72.7% of the chromic, in 36.3% of the nylon, and in 18.1% of the vicryl fixed groups. There were no abscess formations in the dartos and autologous fascial fixed group. Examination of the testes revealed complete absence of spermatogenesis in the chromic fixed group. Spermatogenesis was normal, 72% in the vicryl, 18.1% in the nylon, 90.9% in the datos and autologous fascial suture fixed groups. Antisperm antibody was not observed in any rat sera. We consider that it is preferred to use dartos pouch fixation. If necessary, it is advisable to use autologous fascial suture materials.     

Re-orientation of clinical research in traumatic brain injury: report of an international workshop on comparative effectiveness research

During the National Neurotrauma Symposium 2010, the DG Research of the European Commission and the National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS) organized a workshop on comparative effectiveness research (CER) in traumatic brain injury (TBI). This workshop reviewed existing approaches to improve outcomes of TBI patients. It had two main outcomes: First, it initiated a process of re-orientation of clinical research in TBI. Second, it provided ideas for a potential collaboration between the European Commission and the NIH/NINDS to stimulate research in TBI. Advances in provision of care for TBI patients have resulted from observational studies, guideline development, and meta-analyses of individual patient data. In contrast, randomized controlled trials have not led to any identifiable major advances. Rigorous protocols and tightly selected populations constrain generalizability. The workshop addressed additional research approaches, summarized the greatest unmet needs, and highlighted priorities for future research. The collection of high-quality clinical databases, associated with systems biology and CER, offers substantial opportunities. Systems biology aims to identify multiple factors contributing to a disease and addresses complex interactions. Effectiveness research aims to measure benefits and risks of systems of care and interventions in ordinary settings and broader populations. These approaches have great potential for TBI research. Although not new, they still need to be introduced to and accepted by TBI researchers as instruments for clinical research. As with therapeutic targets in individual patient management, so it is with research tools: one size does not fit all.     

Efficacy of intraoperative mapping to optimize the surgical ablation of atrial fibrillation in cardiac surgery

BACKGROUND: Observation during open heart surgery in patients with chronic atrial fibrillation (AF) showed that the activation sequence of the left atrium was regular and that of the right atrium chaotic in most patients. We speculate that the left atrium plays a role as an important electrical driving chamber for AF and by mapping pre-operatively, optimal sites for the cryoablation can be determined to minimize the extensiveness of the cryolesions. METHODS: Forty patients who underwent cardiac surgery and cryoablation guided by epicardial mapping data to eliminate AF originating from the left atrium were included in this study. RESULTS: Sustained reentrant movement or repetitive firing from foci located in the right atrium was never observed. Foci or reentry circuits located in the left atrium were clearly identified in 11 cases. Nine of the 11 cases resumed sinus rhythm by placing cryolesions at these sites. Two cases needed a pacemaker implantation. The exact site had not been identified in the 29 remaining cases. In these 29 cases a left atrial posterior longitudinal linear cryoablation was placed. Sinus rhythm resumed in 22 cases. Six cases still remained in AF and a pacemaker was implanted in 1 case. Ultimately, in this series of operations sinus rhythm was resumed in 31 of 40 cases; AF remained in 6 of them and pacemaker implantation was required in 3 cases. CONCLUSIONS: Mapping was useful to distinguish the two etiologies of the AF to facilitate optimal placement of the cryolesions. Sustained reentrant movement or repetitive firing from foci located in the right atrium was never observed and the left atrium played an important role as the electrical driving chamber for AF.     

Embolus of surgical adhesive to the extremities causing acute ischemia: report of two cases

We present 2 cases in which a surgical adhesive embolized to the extremities. In the first case an adhesive was successfully used in the repair of a DeBakey type I aortic dissection. The patient was seen 2 months postoperatively with acute lower extremity ischemia, and a large piece of adhesive was extracted from the iliac and femoral arteries at embolectomy. In the second case the adhesive was used to seal a pericardial patch during repair of a ventricular septal defect. This patient was seen 1 day postoperatively with acute arm ischemia, and the adhesive particle was extracted from the brachial artery during embolectomy.     

Nutritional supply to the cauda equina in lumbar adhesive arachnoiditis in rats

Laminectomy-induced cauda equina adhesion has been proved by rat experiments and postoperative serial MRI in humans. A degenerative change of the cauda equina has been proved when cauda equina adhesion has been prolonged. Since it has not been reported how the nutritional supply is changed in such a condition, we evaluated the glucose supply to the adhered cauda equina in rats. Wistar rats were divided into the following three groups: the control group which received no operation, the laminectomy group which underwent L5-L6 laminectomy only, and the koalin group which received 5 mg of kaolin on the dorsal extradural space following L5-L6 laminectomy. Based on ³H-methyl-glucose uptake study, we analyzed (1) glucose transport from the intraneural vessels to the nerve tissue, and (2) glucose transport from the cerebrospinal fluid to the nerve tissue. We evaluated the relation between the severity of cauda equina adhesion and ³H uptake into the cauda equina. Cauda equina adhesion was observed in 2 of 12 rats in the control group, in 3 of 12 rats in the laminectomy group, and in 18 of 20 rats in the kaolin group. In the ³H-methyl-glucose uptake study, at 12 weeks the glucose transport to the cauda equina from the vessels increased by 44%, and that from the cerebrospinal fluid decreased by 64% in the kaolin group compared with thecontrol group. In the condition of complete cauda equina adhesion, the glucose transport to the cauda equina from the vessels increased by 53% and that from the cerebrospinal fluid remarkably decreased by 72% compared with the normal cauda equina. Considering the greater nutritional importance of the cerebrospinal fluid in the cauda equina, it is most likely that the impairment of nutritional supply to adhered cauda equina may lead to eventual neural degeneration. Received: 8 September 1998 Revised: 28 December 1998 Accepted: 10 February 1999