Comparison of three newer generation freely available intraocular lens power calculation formulae across all axial lengths

Purpose:The aim of this study is to evaluate the accuracy of three newer generation formulae (Barrett Universal II, EVO, Hill-RBF 2.0) for calculation of power of two standard IOLs—the Acrysof IQ and Tecnis ZCB00 across all axial lengths.Methods:In this retrospective series, 206 eyes of 206 patients, operated for cataract surgery with above two IOLs over the last 6 months, were included in the study. Preoperative biometry measurements were obtained from LenstarLS900. By using recommended lens constants, the mean error for each formula was calculated and compared. Then, the optimized IOL constants were calculated to reduce the mean error to zero. Mean and median absolute errors were calculated for all eyes and separately for short (AL<22.5 mm), medium (22.5–24.5 mm), and long eyes (>24.5 mm). Absolute errors and percentages of eyes within prediction errors of ±0.25 D, ±0.50 D, ±0.75 D, and ±1.00 D were compared.Results:Prediction error with using recommended lens constants was significantly lower in the Barrett Universal II formula as compared to the other two formulae. However, after optimizing lens constants, there were no significant differences in the absolute errors between the three formulae. The formulae ranked by mean absolute error were as follows: Barrett Universal II (0.304 D), EVO (0.317 D), and Hill-RBF (0.322) D. There were no significant differences between absolute errors in the three formulae in each of the short-, medium-, and long-eye subgroups.Conclusion:With proper lens constant optimization, the Barrett Universal II, EVO, and Hill-RBF 2.0 formulae were equally accurate in predicting IOL power across the entire range of axial lengths.     

Modular Femoral Sleeve and Stem Implant Provides Long-term Total Hip Survivorship

Background  

A femoral implant with a modular sleeve and stem has been designed to allow independent and complete metaphyseal-diaphyseal fit and fill as well as independent rotation to accommodate anteversion at the time of THA.     

Finite element analysis of customized implant in mandibular reconstruction after tumor resection with and without using customized surgical osteotomy guide

Objectives

The aim of this work was to compare different 12 cases (3 patients * 4 cases = 12 cases) with varying gaps between implant and bone by analyzing the effect of these gaps on implant and screws using FEM.

Methods

In each patient's case 1 using CSOG and in case 2, 3, and 4 without using CSOG tumor cutting was done. Hence in each patient zero gaps at case 1 and overcutting at case 2, 3, and 4 have obtained at different locations.

Results

FEM results reveal that in each patient's case 4 (maximum gap) was more susceptible to loosening of the screws due to higher strains (37%) and implant failure due to higher stress (28%) concentration under the same loading conditions when compared with case 1 (zero gap).

Conclusions

The study reveals that mandibular reconstruction with implant placement using CSOG can significantly enhance the stability and safety of the implant.     

Optic disc haemorrhages and vascular abnormalities in a glaucoma population

Purpose: To retrospectively examine the optic disc photographs of a glaucoma population for optic disc haemorrhages, vascular occlusions and vascular abnormalities. Methods: The optic disc photographs of 906 eyes of glaucoma and suspect glaucoma patients were examined. Optic disc photographs were taken annually, where possible, with the follow-up period varying between 1 and 14 years duration (mean, 2.89). Glaucoma patients are regularly reviewed every 4–6 months and glaucoma suspects every 1–2 years, depending on the ophthalmologist. Low-tension glaucoma patients were reviewed more frequently (mean, every 2.6 months). The results of the findings were compared to a control group of 39 subjects with a mean follow-up period of 7 years, using Fisher's exact test. Results: It was found that during the period under review, 7.4% (n= 67) of eyes had optic disc haemorrhages. The highest frequency of optic disc haemorrhages (37.5%) was found in the low tension glaucoma group (P= 0.0001) followed by 11.4% of primary open-angle glaucoma eyes (P= 0.03). In the normal group there were three eyes with optic disc haemorrhages and one with a disc collateral, which constitutes 5.1% vascular changes in this sub-group. Of the study eyes 2.8% had central retinal vein occlusions, 1.3% branch vein occlusion, 1.2% disc vessel abnormalities (loops) and 1.1% disc collaterals. Discrete nerve fibre layer haemorrhages and microaneurysms were found in 0.8% and 1.8% of eyes, respectively. Conclusions: A total of 16.8% of the eyes observed in this study had either disc haemorrhages or vascular changes. The underlying trend of vascular and haemorrhagic changes in glaucoma are demonstrated in this sample, which is in general agreement with previous studies. The high percentage of optic disc haemorrhages in low tension glaucoma is highlighted. The presence of microaneurysms and nerve fibre layer haemorrhages is interesting but of unknown significance.     

Seizures following cardiac surgery: the impact of tranexamic acid and other risk factors

Background

Seizures after cardiac surgery are a serious complication. The antifibrinolytic agent tranexamic acid (TA), which has known proconvulsant properties, may be associated with postoperative seizures. We sought to determine the association between TA and other risk factors for seizures after cardiac surgery.

Methods and results

We analyzed a database of consecutive cardiac surgery patients (April 2003 to December 2009) using multivariable logistic regression analysis to assess for seizure risk factors. Seizures occurred in 56 of 5,958 patients (0.94%). TA use was associated with an increased risk of seizures (odds ratio 7.4, 95% confidence interval 2.8?C19.3; P??20; preoperative cardiac arrest; preoperative neurological disease; open chamber surgery; cardiopulmonary bypass time?>?150?min; and previous cardiac surgery. Seizures occurred at a median of 5.3 hr (interquartile range 2.4?C15.1 hr) after the end of surgery. In all, 58.1% were grand mal, 14.5% were associated with a stroke, and 58.1% recurred in hospital. Altogether, 48.3% of the patients were able to discontinue anticonvulsant medications prior to discharge. Compared to the non-seizure group, seizure patients had an increased rate of postoperative neurological complications, defined as delirium and/or stroke (3.2% vs 19.6%, P?vs 4.7?days, P?<?0.001), and increased ICU mortality (1.4 % vs 9.7 %, P?=?0.001).

Conclusions

Our data suggest that multiple risk factors, including TA, are associated with seizures after cardiac surgery. Thus, the TA dose may be a readily modifiable risk factor for postoperative seizures.     

An application of a proposed framework for formulary listing in low-income countries

Background

The General Mutual Benefit Fund for Civil Servants and State Employees of Côte d’Ivoire (MUGEFCI; Mutuelle Générale des Fonctionnaires et Agents de l’État de Côte d’Ivoire) is a health mutual fund providing coverage (medical consultations, laboratory tests and treatment) for its enrolees (government officials and agents). This organization aims to improve its current drug reimbursement process because of budgetary constraints. One method of achieving this is to implement a formulary-listing framework specifically developed for low-income countries.

Objective

The aim of this study was to evaluate the feasibility of developing a new formulary for the MUGEFCI in Côte d’Ivoire, by implementing a formulary-listing framework specifically designed for under-researched settings.

Methods

The application of this formulary-listing framework (based on multi-criteria decision analysis [MCDA]) consisted of four steps. First, relevant formulary-listing criteria and their levels of variation were identified and weighted according to their importance in the decision making around drug reimbursement. Second, a set of priority treatments to be assessed was determined. Once the treatments eligible for reimbursement were determined, scores were assigned to these treatments according to their performance on the formulary-listing criteria levels. Finally, a composite league table (weighted matrix) was constructed to rank the set of treatments by priority order of reimbursement. A budget-impact analysis (BIA) was also conducted to appraise the economic implications of the new composite drugs league table. The extent to which the new priority list of reimbursable drugs was affordable for the MUGEFCI was then measured.

Results

Policy makers in Côte d’Ivoire considered severity of disease and cost effectiveness of treatment to be the most significant criteria for priority reimbursement of drugs. This translated into a general preference for antimalarials, treatments for asthma and antibacterials for urinary tract infection. Moreover, the results of the BIA suggest that the new priority list of reimbursable drugs would be affordable if the real economic impact of drugs per member is less than $US66. Over this threshold, the MUGEFCI would have to select reimbursable drugs according to their rank in the priority list and their respective budget impact per patient (cost per patient). This selection would start from the first treatment, going down the list until the $US66 per patient is exhausted.

Conclusion

It was possible to use MCDA to simultaneously consider different decision criteria for drug reimbursement in Côte d’Ivoire; therefore, it is feasible to use MCDA to establish a formulary for low-income countries. The application of this method is a step towards transparency in policy making.