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     

Indicators of a Reduced Intercarotid Artery Distance in Patients Undergoing Endoscopic Transsphenoidal Surgery

Objective To identify clinicopathologic factors associated with a reduced intercarotid distance (ICD) and subgroups at risk for internal carotid artery injury during transsphenoidal surgery. Design A retrospective case-control study. Setting This study was conducted at the McGill University Health Centre, a university-affiliated tertiary care center. Participants Patients with a sellar or parasellar tumor and nontumor controls were included in the study. Main Outcome Measures The smallest distance between the internal carotid arteries at the clival, cavernous, and paraclinoid segments on coronal magnetic resonance imaging was measured. Demographic profiles, cephalometric measurements, tumor dimensions, and sphenoid configuration were assessed as potential determinants of the ICD. Results A total of 212 cases and 34 controls were analyzed. Widening of the ICD at the three segments of the internal carotid arteries was found in patients with pituitary macroadenomas (p < 0.01). Patients with a growth hormone–secreting adenoma had a markedly reduced ICD at the clivus compared with controls (1.59 cm versus 1.77 cm; p = 0.02; 95% confidence interval [CI], 0.03–0.32). The paraclinoid ICD was reduced in patients with an anterior fossa meningioma (1.24 cm versus 1.33 cm; p = 0.04; 95% CI, 0.01–0.45). Conclusion Identifying clinicopathologic factors affecting the ICD can help surgeons recognize constraints to endoscopic access of the skull base and avoid inadvertent arterial injury.     

A Rare Case of Carcinoma Cuniculatum Involving the Larynx in Association with a Saccular Cyst

Carcinoma cuniculatum (CC), a rare, well-differentiated variant of squamous cell carcinoma, is uncommon in head and neck sites but when it does occur is most common in the oral cavity. Here we report a rare case of CC involving the larynx. A 49-year-old man presented with 10 months of worsening hoarseness and, despite multiple biopsies, no diagnosis of malignancy could be established. Eventual partial excision of the lesion and histologic review of prior specimens confirmed the diagnosis of CC. Focally, a transition to respiratory epithelium indicated the presence of an associated saccular cyst. Total laryngectomy was performed and 6 months later the patient is free of disease. Only two prior cases of CC have been reported in the larynx. Diagnosis of CC is challenging given the low grade histologic features and awareness of this entity for both treating physicians and the pathologist is important to reach a diagnosis of malignancy. This case highlights the challenges in diagnosis of CC, especially in unusual locations and when associated with other lesions such as a saccular cyst. Awareness of this rare tumor type combined with close communication between treating clinicians, radiologists and pathologists should allow earlier diagnosis and treatment.     

Pulmonary function indices in children with sickle cell anemia in Enugu,south-east Nigeria

Objectives:

To determine the pulmonary function indices of children with sickle cell anemia (SCA) attending the pediatric sickle cell clinic at the University of Nigeria Teaching Hospital, Enugu, south-east Nigeria and to compare these indices with the results obtained from other regions.

Methods:

A case control study of lung function in children with SCA aged 6-20 years. The study was carried out in the University of Nigeria/University of Nigeria Teaching Hospital, Enugu State, Nigeria between October 2014 and January 2015. Measurements of the peak expiratory flow rate, forced vital capacity (FVC), and forced expiratory volume in one second (FEV1) were evaluated.

Results:

A total of 80 subjects were recruited into the study, comprising 40 homozygous HbSS (hemoglobin SS) patients and an equal number of controls. Children with SCA had statistically lower values of FEV1 (1.6±0.52), FVC (1.76±0.95), and peak expiratory flow rate (PEFR) (309.00±82.64) when compared with normal hemoglobin genotype FEV1 (12.01±0.53), FVC (2.12±0.54), and PEFR (364.10±87.85). The mean FVC, FEV1/FVC, and PEFR were also higher in the male control group compared with the HbSS male group, but these differences were not statistically significant. Female controls had significantly larger FEV1, FVC, and PEFR values compared with the HbSS females.

Conclusion:

The lung function indices were significantly lower in children and adolescents with SCA compared with the matched controls with a hemoglobin genotype AA.Sickle cell anemia (SCA) is a genetic hematological disorder characterized by red blood cells that assume an abnormal, rigid, sickle shape.1 This hereditary disorder contributes the equivalent of 3.4% mortality in children aged <5 years worldwide or 6.4% in Africa.2 The prevalence of SCA in Nigeria ranges from 0.4-3%.3 Approximately 85% of sickle cell disorders and >70% of all affected births occur in Africa.4 It is worth noting that at least 5.2% of the world population carry a significant trait. The clinical consequence of SCA results from obstruction of the microvasculature by the sickle cells and red blood cell hemolysis, which causes multi-systemic manifestation. The lungs are affected in a variety of ways by these pulmonary insults, and recurrence overtime may leave the lungs with chronic interstitial, parenchymal, or vascular damage that compromises pulmonary function.5,6 It has been documented that the prevalence of hypoxemia among SCA children was 13%.4 This prevalence was attributable to the chronic anemic state, micro vascular occlusion of the circulation by sickle hemoglobin, and constant pertubation of the endothelial membrane, and consequent elaboration of endothelial molecules, which are commonly seen among SCA children, especially those with various types of vaso-occlusive episodes.7 This is defined as bone and joint pain or multiple sites of pain needing analgesics or hospitalization.8 Acute and chronic pulmonary complications occur frequently in patients with SCA, and contribute to morbidity and mortality later in life. Although the pathogenesis of chronic pulmonary disease in sickle cell disease (SCD) has not been clearly defined, recurrent microvascular obstruction resulting in the development of pulmonary hypertension, endothelial dysfunction, and parenchymal fibrosis are probably the primary mechanisms.6 There is increasing evidence that repeated episodes of acute chest syndrome (ACS) may cause permanent damage to the pulmonary parenchyma and vasculature. Repeated attacks of ACS are a major risk factor for the development of sickle cell chronic lung disease. Studies of lung function in SCD have also demonstrated a restrictive defect,8,9 while a reduction in the total lung capacity (TLC) of 50% has been reported in advanced forms. Acute chest syndrome refers to a spectrum of pulmonary pathology having in common, chest pain, fever, dyspnea with abnormal clinical, and radiologic chest signs as well as leucocytosis.10,11 It is the most common cause of death in children with sickle cell anemia over 10 years of age.12 The etiology of ACS is not clear, lung and bone infarction, infection, and acute pulmonary sequestration, among other possible causes have been proposed.10 In children with sickle anemia in steady state, the major abnormality in pulmonary function is a restrictive pathology, characterized by a slight decrease in total lung capacity, with attendant ventilation perfusion mismatch.10 This can cause a defect in diffusion capacity for carbon monoxide.10 These abnormalities worsen with age and are associated with increases in pulmonary-artery pressures.11 Whereas some studies have documented impaired lung function in SCA (hemoglobin SS) patients,8-10 previous studies8-10 reported what appears to be contrasting findings when the lung function in children with SCA and those of healthy controls with normal hemoglobin genotype were compared. It is therefore necessary that ventilatory function studies be undertaken in this parts of the world to see if there is any difference with known values in other part of the world. In this study, we determine the impact of SCA on the pulmonary function indices in patients attending the pediatric sickle cell clinic at the University of Nigeria Teaching Hospital (UNTH) Enugu, south-east Nigeria and compare it with matched controls and other studies. Many studies have described and assessed the pattern of pulmonary function in SCD from childhood to adulthood, but much is not known on this topic in South Eastern Nigeria. Most of the original studies are from western Nigeria.13,14 This study could therefore corroborate or refute regional or ethnic differences in lung function in children with SCD. The study hypothesis seeks to answer the following questions? Do children with SCA attending UNTH Enugu present with any alteration in lung function? If they do, is there any gender and age difference? Are these lung volume findings similar to that obtained from other region?