Failure of total hip arthroplasties. Numerical modeling of debris formation through plastic strains

The life span of a total hip prosthesis is one of the main points on which the long-term success of arthroplasties depends. It is, by now, widely recognized that hip arthroplasty failure is mainly due to the aseptic loosening resulting from the presence of wear debris forming at the contact interface between the femoral head and the cup of the acetabulum. The size of these particles varies from a few micrometers to some tens of micrometers or more. The main aim of this study was therefore to investigate the formation of debris in the microscopic size range. For this purpose, a numerical study was carried out on various mechanisms leading to plastic deformations, which can lead to damage and wear in material. Numerical analyses were performed with a laboratory software program LMGC90, on the evolution of the plastic strains involved in various wear mechanisms on the microscopic scale.     

Down-regulation of zeta chain and zeta-associated protein 70 (Zap 70) expression in circulating T lymphocytes in laryngeal squamous cell carcinoma

OBJECTIVE: To evaluate zeta chain and Zap 70 expression in T lymphocytes of patients with laryngeal cancer in relation to surgical treatment. STUDY DESIGN: This study investigated, by dual-color flow cytometry, zeta chain and Zap 70 expression in the circulating T lymphocytes of 13 patients with laryngeal cancer patients before and after surgical treatment. RESULTS: Patients exhibited a significant lower expression of both zeta chain and Zap 70 compared to healthy normal controls; no statistical differences were observed after surgical treatment. CONCLUSION: The results of this investigation seem to indicate that both the zeta chain and the Zap 70 expression in circulating T lymphocytes are down-regulated in patients with laryngeal cancer and that these changes do not immediately return to normal after surgery. Flow cytometry analysis may represent an easy-to-use procedure for monitoring the immune status of patients with laryngeal cancer.     

Failure of Total Hip Arthroplasties. Numerical Modeling of Debris Formation through Plastic Strains

The life span of a total hip prosthesis is one of the main points on which the long-term success of arthroplasties depends. It is, by now, widely recognized that hip arthroplasty failure is mainly due to the aseptic loosening resulting from the presence of wear debris forming at the contact interface between the femoral head and the cup of the acetabulum. The size of these particles varies from a few micrometers to some tens of micrometers or more. The main aim of this study was therefore to investigate the formation of debris in the microscopic size range. For this purpose, a numerical study was carried out on various mechanisms leading to plastic deformations, which can lead to damage and wear in material. Numerical analyses were performed with a laboratory software program LMGC90, on the evolution of the plastic strains involved in various wear mechanisms on the microscopic scale.     

Decomposition of variation of mixed variables by a latent mixed Gaussian copula model

Many biomedical studies collect data of mixed types of variables from multiple groups of subjects. Some of these studies aim to find the group-specific and the common variation among all these variables. Even though similar problems have been studied by some previous works, their methods mainly rely on the Pearson correlation, which cannot handle mixed data. To address this issue, we propose a latent mixed Gaussian copula (LMGC) model that can quantify the correlations among binary, ordinal, continuous, and truncated variables in a unified framework. We also provide a tool to decompose the variation into the group-specific and the common variation over multiple groups via solving a regularized M-estimation problem. We conduct extensive simulation studies to show the advantage of our proposed method over the Pearson correlation-based methods. We also demonstrate that by jointly solving the M-estimation problem over multiple groups, our method is better than decomposing the variation group by group. We also apply our method to a Chlamydia trachomatis genital tract infection study to demonstrate how it can be used to discover informative biomarkers that differentiate patients.     

Diagnosis and reconstruction of the human temporomandibular joint after trauma or internal derangement

This study reviewed the standardized records of 1100 patients with the symptoms of temporomandibular joint syndrome. Of these patients, only 4.5 percent required surgical intervention. The remaining patients were found to have masticatory muscle spasm and were treated by conservative dental methods. Over half the surgical patients had significant macrotrauma to the jaws in their past history. In addition, electromyographic measurement of the masseteric silent period duration in these patients did not reveal muscle spasm. These factors further serve to differentiate the surgical patient from the patient with myofascial pain dysfunction. The patients selected for surgery demonstrated moderate to severe joint disease and required arthroplasty with partial meniscectomy. A surgical technique is presented demonstrating the reconstruction of the meniscus with silicone implant. This same surgical technique is studied in 10 monkeys, and their joints are examined histologically. The results of surgery reveal that 87 percent of the patients reported improvement 1 year after surgery. In all patients complaining of temporomandibular joint clicking or crepitus, surgery produced complete alleviation of these symptoms. The results of surgery were also associated with a 62 percent increase of jaw opening. Histologic evaluation of the human meniscal resections revealed that in addition to an anatomic displacement of the meniscus, there are also significant cellular changes. These changes consisted of calcification, a decrease in cellularity, hyperemia, and a decrease in elastin content.     

Injuries from antipersonnel mines: the experience of the International Committee of the Red Cross.

OBJECTIVE--To describe and quantify patterns of injury from antipersonnel mines in terms of distribution of injury, drain on surgical resources, and residual disability. DESIGN--Retrospective analysis. SETTING--Two hospitals for patients injured in war. SUBJECTS--757 patients with injuries from antipersonnel mines. MAIN OUTCOME MEASURES--Distribution and number of injuries; number of blood transfusions; number of operations; disability. RESULTS--Pattern 1 injury results from standing on a buried mine. These patients usually sustain traumatic amputation of the foot or leg; they use most surgical time and blood and invariably require surgical amputation of one or both lower limbs. Pattern 2 injury is a more random collection of penetrating injuries caused by multiple fragments from a mine triggered near the victim. The lower limb is injured but there is less chance of traumatic amputation or subsequent surgical amputation. Injuries to the head, neck, chest, or abdomen are common. Pattern 3 injury results from handling a mine: the victim sustains severe upper limb injuries with associated face injuries. Eye injuries are common in all groups. CONCLUSIONS--Patients who survive standing on a buried mine have greatest disability. Non-combatants are at risk from these weapons; in developing countries their social and economic prospects after recovery from amputation are poor.     

MRI and computerized tomography in the evaluation of lumbar spine after herniated disk surgery]

The authors analyze the results of comprehensive radio-diagnosis in 44 patients previously operated on for lumbar hernias. All the findings of magnetic resonance tomography and computer-aided tomography were divided into 3 groups: (1) natural consequences of a surgical intervention without clinical manifestations; (2) complications after a surgical intervention; (3) recurrent hernias or hernias on an adjacent level. The most intricate problem was the differential diagnosis between a recurrent hernia and a postoperative epidural cicatrix. Criteria to distinguish between these two conditions are suggested. The authors emphasize that the optimal variant for examination of the patients operated on is a combination of magnetic resonance tomography and computer-aided tomography.     

Revision surgical hair restoration: repair of undesirable results

Surgical hair restoration has been performed as a treatment for male pattern hair loss for more than 40 years. Although techniques have changed dramatically over the past several years, making it possible to achieve natural-appearing results, there are still many patients with unacceptable outcomes. These patients may have had procedures performed in the past with antiquated techniques or performed recently with substandard techniques. The causes of unfavorable results can be classified into one of three categories: technical errors, poor planning, or complications. The results in these patients can be dramatically improved through a number of different reparative surgical techniques. The majority of these techniques can be performed in an office outpatient setting. More than 40 patients unsatisfied with previous surgical hair restoration have been treated with the different techniques reviewed in this article. All patients had successful outcomes with significant improvement in appearance. Despite the increased challenges when performing reparative surgery, outcomes were favorable in all patients, with small to significant improvements in appearance achieved. Some of these challenges include the limited supply of donor hairs, reduced scalp laxity, and theoretically reduced vascularity due to scarring and transected blood vessels, and patient skepticism. Furthermore, the few complications that occurred were minor and correctable, including one case each of poor hair growth associated with extensive small graft (consisting of one to four hairs) transplanting, and of scalp scarring associated with the removal and primary closure of a large number of "plug" grafts (typically grafts 3 to 4 mm in size consisting of seven or more hairs) in a single procedure.     

Hybrid repair of a very late, post-aortic coarctation surgery thoracic aneurysm: a case report

ABSTRACT: INTRODUCTION: Local aneurysms after surgical repair of coarctation of the aorta occur mainly in patients surgically treated by Dacron patch plasty during adulthood. The management of these patients is always problematic, with frequent complications and increased mortality rates. Percutaneous stent-graft implantation avoids the need for surgical reintervention. CASE PRESENTATION: We report a case involving the hybrid treatment by stent-graft implantation and transposition of the left subclavian artery to the left common carotid artery of an aneurysmal dilatation of the thoracic aorta that occurred in a 64-year-old Caucasian man, operated on almost 40 years earlier with a Dacron patch plasty for aortic coarctation. Our patient presented to our facility for evaluation with back pain and shortness of breath after minimal physical effort. A physical examination revealed stony dullness to percussion of the left posterior thorax, with no other abnormalities. The results of chest radiography, followed by contrast-enhanced computed tomography and aortography, led to a diagnosis of giant aortic thoracic aneurysm. Successful treatment of the aneurysm was achieved by percutaneous stent-graft implantation combined with transposition of the left subclavian artery to the left common carotid artery. His post-procedural recovery was uneventful. Three months after the procedure, computed tomography showed complete thrombosis of the excluded aneurysm, without any clinical signs of left lower limb ischemia or new onset neurological abnormalities. CONCLUSIONS: Our patient's case illustrates the clinical outcomes of surgical interventions for aortic coarctation. However, the very late appearance of a local aneurysm is rather unusual. Management of such cases is always difficult. The decision-making should be multidisciplinary. A hybrid approach was considered the best solution for our patient.     

Orthognathic surgery in cleft patients

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Identify the skeletal changes in the cleft patient that necessitate surgery. 2. Describe the orthodontic principles that precede surgical treatment. 3. Demonstrate the surgical principles involved in cleft orthognathic surgery and how to avoid common pitfalls particular to cleft orthognathic surgery. 4. Anticipate when dentoalveolar distraction can help in the treatment of problems not easily treated with conventional orthognathic techniques. SUMMARY: This CME article covers the basic multidisciplinary approach to the treatment of patients requiring a combined orthodontic orthognathic approach to their skeletally based malocclusion. The dentoskeletal abnormalities are described for these patients, as are the fundamental orthodontic principles in the presurgical treatment of these patients. The basic surgical principles are discussed in general, and the reader is provided with advice on avoiding common pitfalls. Specific attention is given to the more recent advances in dentoalveolar distraction in cases of large defects that would have been difficult to treat using conventional orthognathic surgery. Videos are provided to illustrate the general principles in treating the cleft orthognathic patient and to illustrate the treatment of large defects using dentoalveolar distraction.     

腰椎间盘突出合并脊柱滑脱患者的手术治疗观察

目的:研究手术治疗腰椎间盘突出合并脊柱滑脱的临床疗效。方法:将腰椎间盘突出合并脊柱滑脱的120例患者随机分为两组,其中对照组54例采取保守(非手术)治疗;观察组66例采取手术治疗,对所有接受治疗的患者进行6至9个月不等(平均8个月)的随访,采用视觉模拟评分(VAS)以及腰椎功能障碍指数评分(ODI)两组结果,比较保守和手术治疗的效果。结果:根据VAS和ODI评价结果,手术治疗组疗效明显优于保守治疗组,两治疗组的比较差异具有统计学意义(P0.05)。结论:手术治疗腰椎间盘突出合并脊柱滑脱效果优于保守治疗,是一种安全、有效的方法,能显著改善临床症状,疗效显著。     

Recurrent mammary hyperplasia: current concepts

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the factors leading to undesirable long-term reduction mammaplasty results. 2. Delineate the differential diagnosis of recurrent hypermastia. 3. Understand the significance of preoperative counseling, particularly with regard to expected postoperative outcome. 4. Understand short-term and long-term expected and undesirable postoperative results. 5. Understand safe and effective surgical planning for revision reduction mammaplasty. A large majority of patients who undergo reduction mammaplasty are satisfied with their aesthetic outcome and resolution of preoperative symptoms. Occasionally, patients present with postoperative concerns; these are usually aesthetic in nature and caused by breast scarring, breast asymmetry, and/or breast shape. Inadequate excision and recurrent hypermastia are more complex concerns, which require careful evaluation and treatment. Analysis of both the presenting deformity and the original surgical approach is critical in determining an operative plan. This article discusses the safe approach to revision reduction mammaplasty. Current concepts are discussed and presented. An algorithm for decision-making is presented and discussed.     

CO2激光、LD激光联合治疗牙龈瘤46例疗效观察

目的：研究CO2激光、LD激光联合治疗牙龈瘤及保存牙体组织的临床疗效。方法：对46例口腔牙龈瘤患者发病的年龄,性别,好发部位进行分析,采用CO2激光、LD激光联合治疗机,先用CO2激光束切割肿瘤,而后CO2激光气化肿瘤波及牙齿的牙周膜,术后第二天用LD激光,每日一次,每次15分钟,连续5天照射手术创面。结果：46列牙龈瘤患者,42例一次治疗痊愈,4例复发,二次手术后无复发,手术疗效、治愈率100％。结论：CO2激光、LD激光联合切除牙龈瘤与传统的手术方法,治疗疗效机理进行了对照,其特点是保存了肿瘤波及的牙齿,不造成组织缺损,还具有手术时间短,出血少,愈合快等优点。     

Use of fast-setting hydroxyapatite cement for secondary craniofacial contouring

Patients who have previously had surgical correction of major craniofacial deformities will often have residual contour deformities they wish to have improved at a later date. The development of hydroxyapatite cement has simplified these procedures. The setting time is reduced to 5 to 8 minutes by mixing the cement with a phosphate-based solution, increasing the tensile strength, and maintaining the same biocompatibility and osseoconductivity. This study includes 48 patients who presented with a variety of residual contour irregularities secondary to a craniofacial congenital anomaly or a posttraumatic defect. All but one of the patients with congenital craniofacial conditions had their initial surgical correction performed by the senior author (Magee) and had regular follow-up visits. Variable amounts of hydroxyapatite cement were used according to the size of the defect to be corrected. Five patients had a postoperative complication: two infections, one seroma, one persistent swelling, and one drain retention. Patients were followed from 6 months to 3 years (mean, 1 year 5 months). Good results were achieved in 38 patients, acceptable results with minor asymmetries were seen in seven patients, and three other patients required a second intervention to obtain a better contour. Cranioplasty with fast-setting hydroxyapatite cement is a simple and reliable procedure, with a low complication rate. Attention to simple technical and operative principles can provide excellent results.     

Lipoaspiration and its complications: a safe operation

Although lipoaspiration has been considered a safe surgical procedure for the last 30 years, reports indicate that this procedure has a high index of complications. This study was performed to analyze experience with patients in a clinical practice for the past 8 years who underwent lipoaspiration, either alone or in combination with another surgical procedure, and to compare the results with previous reports in the literature. The patients were divided into four groups: lipoaspiration alone of less than 5 liters, lipoaspiration alone of more than 5 liters, lipoaspiration combined with abdominoplasty, and lipoaspiration combined with another surgical procedure. Complications were divided into minor or major, depending on previous reports, and statistical analysis was used to determine any significant difference among the four groups. From January of 1994 to December of 2001, 1047 patients underwent lipoaspiration, either alone or in combination with another surgical procedure. A 21.7 percent incidence of minor complications was noted, as well as a 0.38 percent incidence of major complications. Minor complications included palpable and visible irregularities, seromas, cutaneous hyperpigmentation, overcorrection, cutaneous slough, and local infection. Major complications included fat embolism syndrome, cutaneous necrosis, and extended infection. No statistical difference was noted among the groups studied. The incidence of complications was similar to that in clinical reports in the world literature, being of a low percentage rate when compared with the reports of other types of surgical procedures. On the basis of these results, lipoaspiration continues to be a safe surgical procedure, but to maximally avoid complications, one should be mindful of all the factors that could predispose to them.     

巨大痛风石手术切除一例及文献复习

目的:探讨晚期巨大痛风石结节的临床表现及手术治疗效果.方法:回顾性分析一例典型病例患者的临床资料、手术方法的选择以及病理学表现.结果:该患者为晚期通风症患者,发展为痛风石.表现为痛风石结节增生,破坏肌腱以及骨组织.各项辅助检查以及手术后病理结果均支持痛风病的诊断.通过手术切除第一跖趾关节旁巨大痛风石,疗效满意.结论:痛风是一种因嘌呤代谢紊乱所致的疾病,本例患者经过各种保守对症治疗均无效.接收此患者后,通过文献复习分析以及临床检查确诊,本病例痛风病变已发展至晚期巨大痛风石结节.只有通过手术治疗才能彻底治愈.手术后证明对晚期巨大痛风石结节同时伴有骨关节破损的痛风石患者行手术治疗是完全可行,且疗效显著.     

乳腺癌患者术后生命质量及影响因素的调查研究

目的:乳腺癌是我国女性最常见的恶性肿瘤。生命质量作为一种新的医学综合评价技术,包括了对患者身体状况、心理、社会功能以及与疾病或治疗有关的症状等情况的全面评估,其在癌症患者疗效评估中的应用日益增多。乳腺癌患者生命质量调查量表QLICP-BR具有中国文化特色、适合中国国情,具有较好的效度、信度和一定的反应度,适用于中国乳腺癌患者的生命质量测定。本研究旨在观察乳腺癌患者术后生命质量情况并评估各因素对其生命质量的影响,为进一步提高乳腺癌患者术后生命质量提供指导。方法:采用乳腺癌患者生命质量调查量表QLICP-BR收集资料,调查245名住院治疗的乳腺癌患者术后一般情况及生命质量,并分析其影响因素。结果:乳腺癌患者术后生存质量总分为88.44±12.32,其主要影响因素有患病年龄、居住环境、文化程度、家庭经济收入、工作状况、婚姻状况、治疗情况、术后时间及目前治疗情况等(P0.05)。其中年龄较长、居住城镇、文化水平较高、收入较高、在职、已婚、手术治疗联合化疗、术后时间较长以及当前正予以放疗的患者的生存质量评分较高。结论:乳腺癌患者术后生命质量为一般水平,多项因素对其有显著影响。临床上应针对主要影响因素制定综合有效的干预措施,提高乳腺癌患者术后的生命质量。     

Selective myectomy for postparetic facial synkinesis

Synkinetic movements are secondary to facial palsy because they appear like a late sequela to spontaneously healing facial nerve injury. They are produced by an involuntary contraction of a muscle group simultaneous with contraction of other homologous muscle groups. The disorderly regeneration of severed axons is responsible for these movements. According to the Lippschitz theory, the regenerating nerve fibers sprout into the wrong peripheral branches. Between 1975 and 1986, 71 patients with facial paralysis were evaluated. Spontaneous recovery from the facial paralysis occurred in 28 of these patients; 14 (50 percent) developed synkinetic movements, and surgical treatment was sought by only 6 patients. In all patients, the lesion of the facial nerve was in the trunk, proximal to the principal ramification. The most frequent clinical finding was simultaneous activation between the orbicularis oculi and the elevators of the corner of the mouth (12 patients) or the elevators of the upper lip (2 patients). In 8 patients, in whom the slight synkinesis was not noticed by the patients, surgical correction was not necessary, but in the other 6 patients with severe aesthetic disturbances, surgical treatment for "disconnection" of the wrong impulses was realized. I obtained this "disconnection" through resection of the involved perioral muscle groups instead of paralysis of the orbicularis oculi. Follow-up of the 6 patients operated with the surgical treatment proposed herein for between 4 and 8 years has shown good aesthetic results without functional or aesthetic sequelae.     

Temporal trends in the surgical outcomes of patients with breast cancer

ABSTRACT: BACKGROUND: The incidence of breast cancer has been increasing in Japan over the past three decades, and it is the currently the most common malignancy in Japan. This study investigated the temporal trends of the surgical outcomes in patients with breast cancer. METHODS: We evaluated 543 consecutive patients who underwent breast-cancer resection between 1980 and 2009. The temporal trends in the surgical outcome and clinicopathological features were evaluated separately for the periods covering 1980 to 1989, 1990 to 1999, and 2000 to 2009. RESULTS: The number of patients who underwent resection during these three respective periods were 133, 176, and 234, respectively. All patients were women. The percentage of patients at stages 0 or 1 was 63.2%, 58.5%, and 43.6%, respectively, during the three periods. The mean diameter of tumors in each period was 38, 29, and 30 mm, respectively. The percentage of tumors with positive ER expression was 62.5%, 64.3%, and 69.7%, respectively. In terms of surgical procedures, the use of Halsted's radical mastectomy decreased during each period: from 40.6% of cases to 8.5% and then to 0.4%, while the proportion of breast-conserving therapies increased, from 0% to 12.5%, and finally to 35.9%. The postoperative 10-year survival rates during the three periods were 75.9%, 83.5%, and 84.9%, respectively. The 10-year survival rates of patients with stage II disease during the three periods were 66.2%, 75.7%, and 90.7%, respectively. The prognosis of stage III disease in the three periods also showed a tendency toward improvement, increasing from 37.8% to 64.2%, and finally to 84.5%. CONCLUSION: The survival of patients with stage II and III disease has improved during the past 30 years. Along with the recent advances in drug therapy, the surgical treatment has become less invasive, often because of drug therapy-related modifications.     

The surgical management of fibrous dysplasia of bone

The surgical management of Polyostotic Fibrous Dysplasia (FD) of bone is technically demanding. The most effective methods to manage the associated bone deformity remain unclear. The marked variation in the degree and pattern of bone involvement has made it difficult to acquire data to guide the surgeon's approach to these patients. In light of the paucity of data, but need for guidance, recognized experts in the management of these patients came together at the National Institutes of Health in Bethesda, Maryland as part of an International meeting to address issues related to fibrous dysplasia of bone to discuss and refine their recommendations regarding the surgical indications and preferred methods for the management of these challenging patients. The specific challenges, recommended approaches, and "lessons learned" are presented in hopes that surgeons faced with typical deformities can be guided in the surgical reconstruction of both children and adults with FD.